Long Term Resource Monitoring Program

Program Report

2002-P002

Limnological Monitoring on the

Upper Mississippi River System, 1993–1996:

 Long Term Resource Monitoring Program

 Pool 26 Field Station

October 2002
The Upper Midwest Environmental Sciences Center issues LTRMP Program Reports

to provide Long Term Resource Monitoring Program partners

with programmatic documentation, procedures manuals, and annual status reports.

Cover graphic by Mi Ae Lipe-Butterbrodt

Mention of trade names or commercial products does not constitute endorsement

or recommendation for use by the U.S. Department of the Interior, U.S. Geological Survey.
Limnological Monitoring on the

Upper Mississippi River System, 1993–1996:

Long Term Resource Monitoring Program

Pool 26 Field Station 

by

David M. Soballe, Eric Ratcliff, Brad Kerans, and Tim Mihuc

October 2002

U.S. Geological Survey

Upper Midwest Environmental Sciences Center

2630 Fanta Reed Road

La Crosse, Wisconsin 54603
Suggested citation:

Soballe, D. M., E. Ratcliff, B. Kerans, and T. Mihuc. 2002 Limnological monitoring on the Upper Mississippi River System,

1993–1996: Long Term Resource Monitoring Program Pool 26 Field Station. U.S. Geological Survey, Upper Midwest

Environmental Sciences Center, La Crosse, Wisconsin, October 2002. LTRMP 2002-P002. 18 pp. + Appendixes A–F

Additional copies of this report may be obtained from the National Technical Information Service, 5285 Port Royal Road,

Springfield, VA 22161 (1-800-553-6847 or 703-487-4650). Also available to registered users from the Defense Technical

Information Center, Attn: Help Desk, 8725 Kingman Road, Suite 0944, Fort Belvoir, VA 22060-6218 (1-800-225-3842 or

703-767-9050).
iii

Contents

Page

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v

Abstract: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Introduction ........................................................................ 1

The Upper Mississippi River System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Methods .......................................................................... 6

Study Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Monitoring Network and Sampling Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Sample Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Laboratory Analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Quality Assurance and Quality Control Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

River Discharge Regime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Fixed-site Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Sample Collection and Field Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Fixed-site Sampling Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Stratified Random Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Sample Collection and Field Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Stratified Random Sampling Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Summary and Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Appendix A. Fixed-site Sampling Sites: January 1993–December 1996 . . . . . . . . . . . . . . . . . . . . . . . A-1

Appendix B. Stratified Random Sampling Sites: January 1993–December 1996 . . . . . . . . . . . . . . . . . B-1

Appendix C. Limnological Parameters Measured in the Long Term Resource Monitoring Program . C-1

Appendix D. Water Quality Sample Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D-1

Appendix E. Fixed-site Sampling Data: January 1993–December 1996 . . . . . . . . . . . . . . . . . . . . . . E-1

Appendix F. Stratified Random Sampling Data: 1993–1996 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F-1
iv

Tables

Table 1a. Dams on the Upper Mississippi River . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Table 1b. Dams on the Illinois River ..................................................... 6

Table 2. Period of operation for each of the Long Term Resource Monitoring Program field stations . . 7

Figures

Figure 1. The Long Term Resource Monitoring Program (LTRMP) study area . . . . . . . . . . . . . . . . . . . . 3

Figure 2. Water surface elevation (meters above mean sea level) of the Mississippi River from the head

of navigation near St. Paul, Minnesota, to the confluence of the Ohio River near Cairo, Illinois . . . 4

Figure 3a. Water elevation (meters above mean sea level) at Winfield, Illinois, from 1993 through 1996

(solid line) and the 1940–1996 average annual hydrograph (dashed line) . . . . . . . . . . . . . . . . . . . . 12

Figure 3b. Water elevation (meters above mean sea level) at Grafton, Illinois, from 1993 through 1996

(solid line) and the 1940–1996 average annual hydrograph (dashed line) . . . . . . . . . . . . . . . . . . . . 12

Figure 3c. Water elevation (meters above mean sea level) at Alton, Illinois, from 1993 through 1996

(solid line) and the 1940–1996 average annual hydrograph (dashed line) . . . . . . . . . . . . . . . . . . . . 13
v

Preface

The Long Term Resource Monitoring Program (LTRMP) was authorized under the Water Resources

Development Act of 1986 (Public Law 99-662) as an element of the U.S. Army Corps of Engineers’

Environmental Management Program. The LTRMP is being implemented by the Upper Midwest

Environmental Sciences Center, a U.S. Geological Survey science center, in cooperation with the five Upper

Mississippi River System (UMRS) States of Illinois, Iowa, Minnesota, Missouri, and Wisconsin. The

U.S. Army Corps of Engineers provides guidance and has overall Program responsibility. The mode of

operation and respective roles of the agencies are outlined in a 1988 Memorandum of Agreement.

The UMRS encompasses the commercially navigable reaches of the Upper Mississippi River, as well as

the Illinois River and navigable portions of the Kaskaskia, Black, St. Croix, and Minnesota Rivers. Congress

has declared the UMRS to be both a nationally significant ecosystem and a nationally significant commercial

navigation system. The mission of the LTRMP is to provide decision makers with information for

maintaining the UMRS as a sustainable large river ecosystem given its multiple-use character. The long-term

goals of the Program are to understand the system, determine resource trends and effects, develop

management alternatives, manage information, and develop useful products.

In this report, limnological monitoring conducted by the Pool 26 Field Station from 1993 through 1996

is summarized. Reports of this type provide a synopsis of the collected data and collection methods, as well

as a preliminary report of remarkable or unusual conditions in the system. They are intended to be produced

annually.

This report was prepared under Task 2.2.3.6, Evaluate and Summarize Current Monitoring Results of the

Operating Plan (U.S. Fish and Wildlife Service 1993). This report was developed with funding provided by

the Long Term Resource Monitoring Program.
Limnological Monitoring on the

Upper Mississippi River System, 1993–1996:

Long Term Resource Monitoring Program

Pool 26 Field Station

by 

David M. Soballe

U.S. Geological Survey

Upper Midwest Environmental Sciences Center

2630 Fanta Reed Road

La Crosse, Wisconsin 54603

 Eric Ratcliff, Brad Kerans, and Tim Mihuc

Illinois Natural History Survey

8450 Monclair

Brighton, Illinois 62012

Abstract: Since 1988, the Long Term Resource Monitoring Program (LTRMP) staff have performed basic

limnological field measurements in the Upper Mississippi River System. The period of this report (1993–96)

includes a major revision of the LTRMP sampling design in 1993 that added randomization, broader spatial

coverage, and increased monitoring of tributaries and locations that allow monitoring of material transport. The

1993–96 water quality data for the Pool 26 area show long-term declines in the concentrations of total nitrogen,

nitrate–nitrite nitrogen, and soluble reactive phosphorus after the large flood in 1993. The data also indicate that

contiguous backwaters have unique water quality among the sampling strata, characterized by higher turbidity,

volatile suspended solids, and fluorometric chlorophyll a, and lower total nitrogen and nitrate–nitrite nitrogen.

The Missouri and Illinois Rivers significantly alter the Mississippi River main stem in the Pool 26 study area.

The Missouri River contributes high turbidity, silicate silica, and total suspended solids, whereas the Illinois

River contributes elevated concentrations of total nitrogen, nitrate, total phosphorus, and soluble reactive

phosphorus. Dissolved oxygen concentrations (>5 mg/L) were good in the Mississippi River main stem but were

somewhat lower in the Missouri and Illinois Rivers. In the Illinois River, concentrations fell to or below the

Illinois general use water quality standard of 5 mg/L every summer during 1993–96.

Key words: Annual report, limnology, LTRMP, Mississippi River, water quality

Introduction

The Upper Mississippi River is a major resource of multiple uses that include navigation, water supply,

hydroelectric generation, fish and wildlife habitat, and recreation. Effective management of this resource

requires scientific understanding of the ecosystem and of its long-term trends and conditions. To meet this

need, Congress authorized a Long Term Resource Monitoring Program (LTRMP) for the Upper Mississippi

River System (UMRS). The LTRMP, begun in 1988, is intended to provide scientifically sound and useful

information by using consistent and reliable methods to monitor and evaluate long-term changes in selected

physical, chemical, and biological characteristics. 

The LTRMP water quality staff collects basic information on selected physical and chemical features of

the UMRS to aid in the interpretation or prediction of long- and short-term patterns. The data focus on a

subset of limnological variables (i.e., physicochemical features, suspended sediment, and major plant

nutrients) known to be significant to aquatic habitat in this system. The LTRMP is designed to complement,

not replace or duplicate, the monitoring programs of other state and Federal agencies. It therefore includes

some limnological characteristics not routinely monitored in water quality programs and it excludes others
2

that are of concern primarily for human consumption or regulatory purposes (e.g., chemical oxygen demand,

biochemical oxygen demand, total coliform bacteria, fecal coliform bacteria, fecal streptococcus, heavy

metals, pesticides, and polychlorinated biphenyls). 

The present report is one in a series summarizing limnological monitoring at each of the LTRMP field

stations. This report is intended to (1) document those aspects of sample collection (e.g., sampling times,

period of record, sample locations, and allocations among strata) needed for valid interpretation of the data,

and (2) report limnological conditions. Detailed analyses and interpretation of the limnological data are

reported separately. This report, the first of this specific series, covers multiple years.

To improve readability and increase the usefulness of this document as a reference, the numerous graphic

and tabular summaries are included as appendixes. These appendixes are referenced extensively in the main

body of the report, and each appendix contains explanatory information that allows it to be used as a nearly

independent document.

The data presented here represent a concerted effort by personnel of the Illinois Department of Natural

Resources and the U.S. Geological Survey who collected, compiled, verified, and organized the data. The

specific data used in this report have been archived at the Upper Midwest Environmental Sciences Center

(UMESC), La Crosse, Wisconsin (formerly the Environmental Management Technical Center, Onalaska,

Wisconsin), and are available on request. This archival step isolates these data from the dynamics (additions

and corrections) of the main LTRMP database and thus facilitates the reexamination, reconstruction, or

expansion of the results presented here.

The Upper Mississippi River System

The basin of the UMRS (about 490,000 km2) extends from north-central Minnesota to the Ohio River

confluence near Cairo, Illinois. The enabling authorization for the LTRMP, however, restricts monitoring

to the geological floodplain (about 2% of the total drainage). The LTRMP study areas include selected

sections of the Mississippi River (Navigation Pools 4, 8, 13, and 26), La Grange Pool of the Illinois River,

and the open river reach (Middle Mississippi River) between the Missouri River and Ohio River confluences

(Figure 1). 

Field teams of the LTRMP monitor more than 2,000 km of large river; across this expanse there exist

distinct differences in climate, geomorphology, surficial geology, and land use. Patterns that arise from the

north–south orientation of the system are overlain by upstream to downstream changes related to river size

(Vannote et al. 1980). Consequently, the areas monitored by individual field stations differ markedly in the

distribution and characteristics of aquatic habitat and aquatic biota. The LTRMP monitoring design must

contend with these differences by being flexible enough to accommodate local conditions but appropriately

uniform across all study areas to permit comparison and synthesis.

Dam construction on the Upper Mississippi and Illinois Rivers has profoundly altered these rivers,

creating a series of rapidly flushed impoundments connected by short stretches of flowing river that are

influenced by dam operations (Figure 2).
3

Figure 1. The Long Term Resource Monitoring Program (LTRMP) study area. Although the Missouri River is shown for

reference, only the mouth of this tributary is sampled for water quality under the LTRMP.
4

 

Figure 2. Water surface elevation (meters above mean sea level) of the Mississippi River from the head of navigation

near St. Paul, Minnesota, to the confluence of the Ohio River near Cairo, Illinois. 

The dams on the main stem of the Upper Mississippi River are numbered from upstream to downstream

(starting near St. Paul, Minnesota), and the river reach above each dam is called a pool (Table 1a). The pool

has the same numeric designation as the downstream dam. For example, Pool 14, near Clinton, Iowa,

includes the entire reach of river upstream of Lock and Dam 14 and downstream of Lock and Dam 13. A

similar system is used on the Illinois River, but the individual dams are named rather than numbered

(Table 1b). Although the navigation dams have created significant zones of permanent inundation in

Pools 1–13 of the Upper Mississippi River, these zones are usually less than half the total water surface

within the pool (LTRMP aquatic areas database) and are semifluvial (average hydraulic residence times

<2 days). Between Pools 13 and 26 in the Mississippi River and in most of the Illinois River, the navigation

dams have deepened the river and widened it slightly, but have permanently inundated little terrestrial area

compared with major river impoundments and have created minimal lake-like habitat. The term pool is

therefore misleading inasmuch as it suggests that the UMRS is a stair-step series of lake-like impoundments.

Nonetheless, the term is widely used and recognized by those familiar with the UMRS and it is used freely

in this report.

The first major dam on the Upper Mississippi River was constructed in 1913 near Keokuk, Iowa, and was

followed by 27 additional dams on the main stem to create a 2.7-m (9-foot) navigational waterway from

Alton, Illinois, to St. Anthony Falls near St. Paul, Minnesota. Twenty-two dams were built between 1935 and

1940; the last dam was completed in 1958 at Lower St. Anthony Falls near Minneapolis (Table 1a). The
5

navigation system was altered significantly in 1993 when Lock and Dam 26 at Alton was replaced by a new

structure (Melvin Price Locks and Dam) with increased lock capacity about 3.2 km (2 miles) farther

downstream. The previous Lock and Dam 26 was removed after the new structure was completed.

The history of impoundment on the Illinois River is similar to that of the Upper Mississippi River, and

the Illinois River is now divided into six navigational pools (Table 1b). The first dams were completed on

the upper portions of the Illinois River (Starved Rock, Marseilles, and Dresden Island) in 1933; additional

dams at Peoria and La Grange were completed in 1938. The Melvin Price Locks and Dam on the Mississippi

River near Alton, Illinois, also impounds the lowermost portion of the Illinois River.

Table 1a. Dams on the Upper Mississippi River.

Name of dam

Date placed

 in service City

River

mile

Drainage

area

 (km2)

Dam

height

 (m)

Pool

elevation

(feet)

Lower St. Anthony

Falls 11/13/1958 Minneapolis, Minnesota 853.2 51,000 7.3 750.0

1 07/03/1917 St. Paul, Minnesota 847.6 51,000 11.3 725.1

2 07/01/1931 Hastings, Minnesota 815.2 96,000 3.7 687.2

3 07/21/1938 Red Wing, Minnesota 796.9 117,000 3.7 675.0

4 05/25/1935 Alma, Wisconsin 752.8 148,000 2.4 667.0

5 05/29/1935 Minneiska, Minnesota 738.1 152,000 2.1 660.0

5a 07/06/1936 Winona, Minnesota 728.5 153,000 2.7 651.0

6 06/30/1936 Trempealeau, Wisconsin 714.3 155,000 1.7 645.0

7 04/19/1937 Dresbach, Minnesota 702.5 161,000 2.0 639.0

8 04/26/1937 Genoa, Wisconsin 679.2 168,000 2.4 631.0

9 07/08/1937 Lynxville, Wisconsin 647.9 172,000 3.4 620.0

10 11/26/1937 Guttenberg, Iowa 615.1 206,000 2.7 611.0

11 09/14/1937 Dubuque, Iowa 583.0 211,000 2.4 603.0

12 05/14/1939 Bellevue, Iowa 556.7 213,000 3.4 592.0

13 05/13/1939 Clinton, Iowa 522.5 221,000 2.7 583.0

14 06/14/1939 Le Claire, Iowa 493.3 229,000 3.3 571.9

15 03/07/1934 Rock Island, Illinois 482.9 229,000 4.9 561.0

16 07/10/1937 Muscatine, Iowa 457.2 257,000 2.7 545.0

17 05/14/1939 New Boston, Illinois 437.1 258,000 2.4 536.0

18 09/08/1937 Burlington, Iowa 410.5 294,000 3.0 528.0

19 06/12/1913 Keokuk, Iowa 364.2 308,000 11.6 518.2

20 06/09/1936 Canton, Missouri 343.2 348,000 3.0 480.4

21 07/21/1938 Quincy, Illinois 324.9 348,000 3.2 470.0

22 07/22/1938 Saverton, Missouri 301.2 356,000 3.1 459.5

23a — — — — — —

24 1940 Clarksville, Missouri 273.4 365,000 4.6 449.2

25 05/18/1939 Cap Au Gris, Missouri 241.4 368,000 4.6 434.9

26b 05/01/1938 Alton, Illinois 202.9 443,000 6.7 419.0

Melvin Price 1990–1994 Alton, Illinois 200.8 444,000 7.3 419.0

a

Lock and Dam 23 was never built.

b

Lock and Dam 26 was removed after the Melvin Price Locks and Dam was placed in service.
6

Table 1b. Dams on the Illinois River.

Name of dam

Date placed in

service

River

mile

Drainage

area

 (km2

)

Dam

height

 (m)

Pool

elevation

(feet)

Thomas J. O'Briena 1960 326.5 0 1.2 583.5

Lockport 1933 291.1 1,900 12.3 579.5

Brandon Road 1933 286.0 3,900 10.4 539.0

Dresden Island 1933 271.5 18,800 6.7 505.0

Marseilles 1933 247.0 21,400 7.3 483.0

Starved Rock 1933 231.0 28,600 5.8 459.0

Peoria 1938 157.7 37,700 3.4 440.0

La Grange 1939 80.2 66,400 2.9 429.0

a

This structure controls diversion discharge into the Illinois waterway from outside the drainage basin (Lake Michigan)

Methods 

Study Area

 The study area of the LTRMP includes the Mississippi River from Cairo, Illinois, to the head of

navigation near St. Paul, Minnesota; the Illinois River; and navigable portions of the Kaskaskia, Black, and

St. Croix Rivers. In recognition of the highly variable and widely differing river characteristics within this

large study area, the Comprehensive Master Plan (Jackson et al. 1981) recommended 17 pools or reaches for

detailed monitoring. Available resources, however, have limited the LTRMP to six selected areas, and the

five states bordering the Upper Mississippi River now operate six LTRMP monitoring stations that focus on

these specific reaches. These areas (Figure 1) are concentrated in the uppermost segments of the Mississippi

River. The river sections presently monitored under LTRMP for water quality include Pools 4, 8, 9, 12, 13,

14, and 26 in the impounded portion of the Upper Mississippi River; 130 km (80 miles) of the open river

above the Ohio River confluence at Cairo, Illinois; and La Grange Pool of the Illinois River. All of the major

tributaries of the Mississippi and Illinois Rivers in these river segments are monitored under the LTRMP.

The long (400 km) reach of the Upper Mississippi River between Pools 14 and 26 is not monitored under

the LTRMP, but other state and Federal programs collect water quality information in this reach and

adjoining tributaries (i.e., Iowa-Cedar, Rock, and Des Moines Rivers). 

Personnel from the Illinois Natural History Survey conduct LTRMP monitoring in the vicinity of Pool 26,

defined by Lock and Dam 26 at Mississippi River mile 200.8 and Lock and Dam 25 at Mississippi River mile

241.4. The replacement of Lock and Dam 26 with the present structure (Melvin Price Locks and Dam)

catalyzed the development and authorization of the Environmental Management Program, of which the

LTRMP is a part. Sampling by the LTRMP water quality team extends beyond the limits of Pool 26 and

includes portions of the Mississippi River below Lock and Dam 26, the Missouri River, the Illinois River,

and other tributaries (Figure A-1). Under the LTRMP, water quality has been monitored in the Pool 26 area

since July 1988 (Appendixes A and B).

The Pool 26 study area is a major junction in the Mississippi River drainage basin and includes the

confluences of the Illinois River (near Grafton, Illinois) and the Missouri River (at St. Louis, Missouri).

These major tributaries strongly influence limnological conditions in this study reach, and the Missouri River

input dramatically changes the size and character of the Mississippi River.
7

Six to eight other notable tributaries enter this reach of the Mississippi River. Although their discharge

is minor in relation to that of the Illinois and Missouri Rivers, after locally heavy rainfall their inputs can

dramatically alter the limnological conditions of the Mississippi River; primarily because most of these

streams drain agricultural areas, and some drain highly urbanized areas.

The total water surface area of the pool (between Lock and Dam 26 and Lock and Dam 25) is about

9,300 ha. Most (4,900 ha) is main channel and side channel: a relatively small portion (400 ha) is contiguous

backwater. In recent years, many of the contiguous backwaters have been leveed off from the Mississippi

and Illinois Rivers, and control structures are now used to regulate their connection to the river. Some levees

have been built by private hunting clubs that manage the backwaters for waterfowl hunting. Others have been

constructed by government agencies as part of Habitat Rehabilitation and Enhancement Projects (HREP)

with the intent of reducing sedimentation rates in the backwaters while managing the areas to enhance fish

and wildlife habitat. The largest example of an HREP in the Pool 26 area is at Swan Lake, which alone is

the “lake” sample stratum for the LTRMP in this area.

Monitoring Network and Sampling Design

The LTRMP was begun in 1988; field stations were added to the network from 1988 to 1991 (Table 2).

This staggered start is significant when making comparisons among study areas or assessing overall trends

across the system. Limnological monitoring during the first years (1988–91) was limited to fixed sites and

to in situ physical and chemical measurements. The present LTRMP sampling design (implemented in June

1993) includes both fixed-site (Appendix A) and stratified random sampling (SRS; Appendix B) and

combines in situ field measurements with laboratory analyses of chemical constituents (Appendix C).

Table 2. Period of operation for each of the Long Term Resource Monitoring Program field stations.

Field station 1988 1989 1990 1991 1992–1996

Lake City Jan $$$ $$$$$$ $$$$$$

Onalaska Jul $$$$ $$$$$$ $$$$$$ $$$$$$ $$$$$$

Bellevue Aug $$$ $$$$$$ $$$$$$ $$$$$$ $$$$$$

Pool 26 Jul $$$$ $$$$$$ $$$$$$ $$$$$$ $$$$$$

Open River Mar $$ $$$$$$

Havana Sept $$$ $$$$$$ $$$$$$ $$$$$$

 Fixed-site sampling in the present design monitors inflows (tributaries and dam releases) and outflows

from each of the LTRMP study areas. Secondarily, fixed sites are used to monitor locations of special

significance, either because of their long data record or some other feature that makes them notable or

especially interesting. Each LTRMP field station monitors about 15–30 fixed sites biweekly with no attempt

to capture or avoid high or low flows (Appendix A).

From 1988 to 1993, the LTRMP used 24 aquatic habitat classes (Appendix A) to describe the permanently

fixed monitoring sites. Some of these classes included a seasonally varying attribute (aquatic vegetation) as

part of their definition, and the classes were not mutually exclusive. For example, a site in midchannel

downstream of a dam might be classified as “Main Channel” (MC), “Channel Trough” (CTR), “Open
8

Tailwater” (TWR-O), or “Tailwater” (TW). This classification scheme was revised in 1993 when vegetation

status was dropped from the habitat designators and those categories that were viewed as redundant or not

distinguishable by routine water quality measurements were eliminated. The revised system has seven habitat

classes (Table A-4), and all previous habitat classifications for fixed sites were converted to this system. The

original designations for all fixed sites are permanently on file at UMESC and at the individual field stations.

As with the six field stations, the period of record differs among individual fixed sites. When the emphasis

of fixed-site sampling shifted to tributaries and other transport monitoring points in 1993, sites were added

and eliminated from the sampling network in each study reach. At the same time, sampling frequency at fixed

sites was reduced from weekly to biweekly (Figure A-2) to keep the overall level of monitoring constant

despite the addition of SRS.

The habitat class associated with each fixed site provides useful ancillary information about the site and

a convenient way to retrieve data from the LTRMP database. However, LTRMP fixed-site data cannot be

used generally to make inferences about these habitat classes because fixed sites were chosen subjectively

and without randomization and represent only specific locations. Although the sampling sites can be grouped

by their habitat categories, the resultant groupings are not unbiased samples of these categories. To overcome

this limitation, the monitoring design was modified in 1993 to include SRS and thus provide unbiased

information about broad spatial areas.

The LTRMP design for fixed-site sampling and SRS, established in September 1993, requires that each

day's sampling effort be centered on noon (1200 h), central standard time, and that the order of site visits

within each sampling day be randomized to the extent feasible within operational constraints. 

The SRS complements the fixed-site design and provides a seasonal assessment of known precision and

confidence on limnological conditions in broad sampling strata in the LTRMP study areas. Limnological data

from SRS are intended to be linked to patterns in fish, vegetation, and invertebrates at the spatial scale of a

whole navigational pool or river reach and at temporal scales ranging from seasons to decades. The SRS data

can be interpreted confidently at these scales of space and time. Higher resolution questions (e.g., short-term

movements or locations of fish, growth dynamics within individual aquatic plant beds) are outside the realm

of routine monitoring as defined by the LTRMP and are not addressed by SRS or fixed-site sampling in the

LTRMP monitoring design. 

The SRS is performed in four quarterly episodes each year (Appendix B). Each SRS episode has 100–150

sites selected from six sampling strata and sampling is completed usually within 14 days (Appendix B). The

sampling strata are condensed from the geomorphic “aquatic areas” of Wilcox (1993) and are objectively

defined in a geographic information system (Owens and Ruhser 1996). Specific sampling points for each

sampling episode are selected by overlaying a square grid with 200-m spacing on a map of the sampling

strata. Grid intersections are randomly selected for each sampling episode. Beginning in spring 1995, a 50-m

grid was used for side channel and backwater strata. A smaller grid spacing was deemed appropriate to the

spatially diverse conditions within these strata (i.e., points 50 m apart are likely to be different); this increases

the number of potential sites available for site selection. Although the number of sites selected was not

altered by this change in grid spacing, the number of locations resampled in subsequent episodes was greatly

reduced. The allocation of samples among strata emphasizes off-channel areas and is not proportional to the

surface area of the strata (Appendix B). Data from the strata must be weighted to obtain accurate poolwide

or reachwide estimates, and this weighting must account for the areas of the strata, the differing grid intervals

among the strata, changes to the grid in 1995, and the allocation of sampling effort (Appendix B).
9

The sampling strata used by the LTRMP are primarily a statistical tool that allows the spatial allocation

of sampling effort to match differences in desired precision and variability among the strata. An exact

correspondence between sampling strata and the aquatic areas of Wilcox (1993) is not attainable and is not

required by the LTRMP statistical design. The data from a sampling stratum, therefore, should not be

regarded as precisely representing a specific aquatic area type. 

Because the river is dynamic, the borders of the aquatic areas change over time, but the sampling strata

boundaries have been (with minor exceptions) static since their original designation in 1993. Thus the aquatic

areas are expected to gradually diverge from the sampling strata because of long-term changes in river

morphology. In addition, short-term fluctuations in water level can make sites unusable or atypical of their

parent stratum. The field teams use data comments to report sites that cannot be sampled or seem to be

outside their designated sampling stratum. These comments are extremely valuable for data interpretation

and also give a rough indication of the rate or extent of divergence between the sampling strata and the

aquatic areas. However, field comments lack the spatial intensity and consistency required for tracking or

mapping changes in stratum boundaries, and the LTRMP staff intends to track changes in aquatic areas by

systemwide remapping and reclassification of areas at regular (e.g., 10-year) intervals. If future remapping

results in new sampling strata, all sampling locations will have both pre- and postrevision stratum codes

assigned. This will allow analysis for the full period of monitoring to be based on either mapping scheme.

The capacity of the LTRMP analytical laboratory has restricted the number of chemical measurements

performed on SRS samples. Consequently, from 1993 to 1996 SRS has included major plant nutrients,

suspended solids, and phytopigments, but has excluded major cations (sodium, magnesium, calcium,

potassium) and major anions (chloride and sulfate). In situ measurements are made at all SRS sites; to reduce

the laboratory sample load, samples are collected for a full complement of laboratory analyses only in a

randomly selected subset (about half) of sites.

Sample Collection

 The LTRMP limnological monitoring includes measurements at multiple depths (Soballe and Fischer

2003). About 80% of LTRMP measurements from 1993 to 1996 were taken near the water surface (0.0 to

0.20 m); laboratory analyses during this period were performed only on near-surface and near-bottom

samples. The LTRMP sampling for water quality is generally restricted to waters 0.2 m deep or deeper.

However, samples are occasionally collected in shallower waters, particularly under ice cover, when they

can be taken without disturbing the substrate. Discrete, rather than integrated, samples are collected and

analyzed. Grabs for chemical analyses are taken with either a bucket (near surface) or a Van Dorn sampler

(at depth). 

When the sampling design was revised in 1993, grab-sampling techniques remained unchanged; however,

individual instruments used to monitor pH, conductivity, temperature, and dissolved oxygen were replaced

by a multiparameter monitoring device used for in situ measurement and recording. The LTRMP Procedures

Manual (Soballe and Fischer 2003) provides additional details.

Ice cover can vary widely in extent and thickness across the study area, complicating sample collection

and the recording of sample information. It is not meaningful, for example, to report limnological conditions

at 0.2 m below the water surface when the ice extends below this depth, nor to report maximum water depth

when ice extends into the substrate. Consequently, when ice is present, LTRMP crews collect near-surface

samples at 0.2 m below the bottom of the ice (where possible). The reported sampling depth in this situation

(0.2 m) must be adjusted for the vertical extent of ice below the water surface (also recorded) to determine
10

the actual vertical location of the sample in reference to the free water surface. Here we summarize the data

by depth sampling category rather than precise vertical location; sampling depths have not been adjusted for

the vertical extent of ice below the water surface. In addition, sites that were frozen to the substrate have been

excluded from the summaries of water depth. 

Laboratory Analyses

The LTRMP added a limited suite of laboratory analyses to the limnological monitoring in 1991 and

expanded the list of chemical constituents in 1993 (Appendix C). From 1991 to 1993, samples for chemical

analyses were collected biweekly during the ice-free period; this frequency was reduced to monthly in winter.

Also during this period, chemical analyses were performed at the Waterways Experiment Station (WES)

laboratories at Vicksburg, Mississippi, and the U.S. Army Corps of Engineers Eau Galle laboratory near

Spring Valley, Wisconsin. In 1993, analysis of LTRMP limnological samples was gradually shifted to the

UMESC (Table C-2).

In late summer and fall 1996, the UMESC analytical laboratory experienced contamination of the

equipment used for total phosphorus analyses. The source of the problem was eventually identified and

eliminated in December 1996; those analytical results affected by this contamination have been excluded

from this report and are identified in the LTRMP database. The laboratory also experienced ammonia

contamination of the equipment in May 1996, which invalidated many of the ammonium samples collected

in spring 1996 SRS episode. Those data have also been excluded from this report. Detailed descriptions of

the methods used by the UMESC and WES laboratories are available on request from the UMESC in La

Crosse, Wisconsin.

Quality Assurance and Quality Control Procedures

The value of LTRMP data depends on their quality and reliability. The use of standard methods to assure

and control the quality of the data are thus extremely important. The original LTRMP procedures (Lubinski

and Rasmussen 1988) gave guidance on instrument calibration, record keeping, data management, and

organizational relations. Revisions to the procedures (Soballe and Fischer 2003) provided details on

assessing the accuracy and precision of field measurements and also addressed issues (i.e., daily and seasonal

sampling windows, randomization of sampling sites and times) related to the conduct of field work.

Guidelines for the time of sampling and randomization of sampling order were implemented in 1993, and

compliance with these guidelines is reported here (Appendix D). 

The LTRMP field teams began collecting additional Quality Assurance and Quality Control (QA/QC)

measurements and samples near the end of April 1995 to assess the accuracy and precision of both laboratory

and field measurements. The QA/QC sampling data are readily available

(http://www.umesc.usgs.gov/data_library/water_quality/water_quality_page.html), but not summarized here.

Following the recommendations of APHA (1992), at least 5% of each type of chemical or physical

measurement collected by an LTRMP water quality team is accompanied by a series of QA/QC

measurements, and each sampling crew is required to perform at least one QA/QC series during each day

of field work. The daily crew requirement results in about 15% of all samples being accompanied by QA/QC

measurements, exceeding the APHA recommendation and LTRMP minimum requirement. Because of

logistic constraints, the LTRMP did not use field spikes (additions of known concentrations of chemical

constituents)in 1993–96, but did collect four types of QA/QC samples:
11

Routine: The regular or routine sample or measurement taken at the site.

Field Split: A field sample that is as similar as possible to the routine sample at the point of collection. It is

used to evaluate laboratory precision and variability introduced by field handling or processing.

Field splits are performed for all the constituents listed in Table C-2 that are presently analyzed.

Blank: A sample used to check for contamination of the analytical water supply or sample containers,

or contamination and losses during handling and storage. It is also used to evaluate precision at

concentrations near the detection limit.

Replicate: A second, separate sample taken at the same location and in the same way as the routine, but

separated by an interval of 5–10 minutes. This provides information on natural, random

background variability in ambient conditions.

Results

River Discharge Regime

River discharge (flow) is a major factor in the ecological and limnological structure and functioning of

the UMRS. Flow strongly influences limnological conditions and, thus, the interpretation of the monitoring

data must consider the hydrologic setting (flow regime) under which the data were collected. Because river

discharge is so important, staff of the LTRMP have assembled the Mississippi and Illinois Rivers discharge

and surface elevation data collected by the U.S. Geological Survey and the U.S. Army Corps of Engineers

into a database at the UMESC (Wlosinski et al. 1995). The discharge and water elevation data used in this

report were obtained from that database.

Water levels in Pool 26 are influenced by discharge from the Mississippi, Illinois, and Missouri Rivers.

The pool is regulated at a midpool control point by the U.S. Army Corps of Engineers. These factors combine

to give Pool 26 a highly fluctuating hydrologic regime, and three sets of hydrographs are needed to accurately

represent the fluctuations in differing portions of this reach (Figure 2). Gages are located at the upper end

of the pool at Lock and Dam 25 tailwater (Winfield Gage; Figure 3a), at midpool (Grafton Gage; Figure 3b),

and at the downstream end near Lock and Dam 26 (Alton Gage; Figure 3c). Flood stages at Winfield,

Grafton, and Alton Gages are 131.98 m (433.0 feet), 128.56 m (421.79 feet), and 128.3 m (421.0 feet) above

mean sea level, respectively. The U.S. Army Corps of Engineers discharge data were obtained from the

UMESC (Wlosinski et al. 1995).

The water elevations at these three gages reflected the midpool regulation scheme used in this reach of

the river. High discharges entering upstream are managed by downstream drawdowns that keep water levels

relatively constant at midpool. The highly regulated nature of the hydrograph is clearly evident at the Grafton

and Alton gaging sites.

Extreme discharges during the flooding of 1993 are evident at each of the gaging sites. This flood was

remarkable not only for the extremely high elevation of the floodwaters, but also for its duration (the entire

spring and summer). The stage data also show that the spring floods (except for 1994) have been above flood

stage and above the 56-year average, and discharge between floods has also been slightly above average.
12

Figure 3a. Water elevation (meters above mean sea level) at Winfield, Illinois, from 1993 through 1996 (solid line) and

the 1940–1996 average annual hydrograph (dashed line). Vertical lines above the horizontal axis indicate dates of

stratified random sampling. Water elevation for flood stage is indicated by the horizontal line.

Figure 3b. Water elevation (meters above mean sea level) at Grafton, Illinois, from 1993 through 1996 (solid line) and

the 1940–1996 average annual hydrograph (dashed line). Vertical lines above the horizontal axis indicate dates of

stratified random sampling. Water elevation for flood stage is indicated by the horizontal line.
13

Figure 3c. Water elevation (meters above mean sea level) at Alton, Illinois, from 1993 through 1996 (solid line) and the

1940–1996 average annual hydrograph (dashed line). Vertical lines above the horizontal axis indicate dates of stratified

random sampling.

Fixed-site Sampling

Sample Collection and Field Measurements

The volume of field work completed by each field station is important to document for planning and

budgetary purposes. The schedule of sample collection is also important to document because many of the

limnological characteristics monitored by the LTRMP exhibit regular daily (diel) patterns. The time of

measurement can thus strongly influence the value that is observed and, because the LTRMP strives to

monitor patterns over time across the UMRS, it is important that sampling times remain consistent and

unbiased with regard to location over the duration of the program, among sampling locations, and among

field stations.

In 1993–96, the Pool 26 water quality team made about 1,700 site visits to fixed sampling locations.

During these visits, about 1,400 grab samples were collected for chemical processing (Appendix E). The

number of site visits during a week of sampling was about 16–20 (Figure D-1 and Table D-1); the redesign

in 1993 had little effect on the weekly number of site visits (Figure D-1). Deviations from the normal fixedsite sampling schedule were sometimes required because of unsafe field conditions or equipment failures

(Table D-1).

The distribution of sampling across the hours of the day (Figures D-2–D-4) also shows little effect of the

September 1993 change in the fixed-site sampling protocol. From 1993 to 1996, sampling was conducted

primarily in the morning hours and shows a broad distribution centered on about 1100 h. This pattern

continued after the sampling window was formally defined and confounds comparison of Pool 26 data to that

obtained by the LTRMP in other reaches. The distribution of median sampling times for sites (Figure D-4)
14

shows a differing pattern each year (Figure D-1) that does not center on 1200 h. The tendency to sample

before noon is pronounced, and there is also a minor, but significant (P < 0.001), linear increase in sampling

time at the fixed sites from 1993 to 1996 (about 3 minutes per year), which probably reflects the continuing

effort of the water quality crew to move the average sampling time as close as possible to 1200 h.

The distribution of fixed-site sampling times across the period of record (Figure D-3) gives some

indication of a seasonal pattern, with earlier sampling in summer and later sampling in winter. The earlier

sampling in summer is due in part to the field team operating on local clock time (daylight savings time),

rather than remaining on central standard time year-round. Sampling in winter was later in the day because

of delays inherent in winter sampling, such as increased travel time through ice and snow and timeconsuming winter safety precautions. Although the forces that cause earlier sampling in summer and later

sampling in winter will continue, the water quality crew is attempting to minimize their effect through better

time management.

Fixed-site Sampling Data

Fixed-site sampling by the Pool 26 Field Station staff from 1993 to 1996 has generated a large volume

of data (Appendix E). These data allow comparisons of tributary and main-stem inflows and outflows within

this study area and thus provide information on sources of material such as nutrients and suspended sediment

and the functioning of the study reach as a processor of those materials.

The fixed-site data document a number of notable patterns and reveal important functional aspects of

Pool 26 and this reach of the Mississippi River, including the differing characteristics of the Mississippi

River main stem, the Illinois River, and the Missouri River. Perhaps the most notable difference in water

quality between the Mississippi and the Missouri Rivers is the consistently higher turbidity in the Missouri

River (Figure E-1b). Not surprisingly, the related parameters, silicate and total suspended solids, are also

higher in the Missouri River (Figure E-2b). The Mississippi River main stem is higher in dissolved oxygen

and chlorophyll a than either the Illinois or Missouri Rivers (Figures E-1 and E-2, Tables E-1 and E-2).

The increase in nitrate from upstream to downstream in Pool 26 (Figure E-2a) suggests that this reach and

its tributaries are a significant source of this material. For example, the Illinois River has concentrations of

total nitrogen, nitrate, total phosphorus, and soluble reactive phosphorus that are usually higher than in the

Mississippi River main stem (Table E-2). In contrast, the Missouri River has total nitrogen and nitrate

concentrations that are usually lower than in the Mississippi River main stem. Total phosphorus is usually

higher in the Missouri River, whereas soluble reactive phosphorus concentrations are roughly similar

between the two rivers but are more variable in the Mississippi River main stem (Appendix E).

The fixed-site data for Pool 26 show a long-term decline in the concentrations of total and nitrate–nitrite

nitrogen and soluble reactive phosphorus after the large flood in 1993 (Figure E-2a). Long-term trends for

other parameters are not as apparent. The fixed-site data show only weak seasonality for the chemical

measurements and for most physical measurements. Exceptions are suspended solids and turbidity, which

are closely tied to the flow regime; suspended solid concentrations and turbidity peaked in each annual spring

flood (Figures E-1 and E-2). 

Dissolved oxygen solubility is a function of water temperature and thus dissolved oxygen shows strong

seasonality at all sites (Figure E-1). Monthly means do not reveal extremes in dissolved oxygen, and the

LTRMP sampling schedule (centered on noon) is not designed to give a good representation of extremely

low (expected near sunrise) or high (expected in mid- or late afternoon) oxygen concentrations. The fixed-
15

site dissolved oxygen data show that during this reporting period, dissolved oxygen levels were good

(>5 mg/L) in the Mississippi River main stem and were somewhat lower in the Missouri and Illinois Rivers.

In the Illinois River, where summertime dissolved oxygen concentrations reached especially low levels,

concentrations reached 5 mg/L or less every summer during 1993–96 (Appendix E). A 5 mg/L minimum is

the Illinois State water quality standard for general use.

Stratified Random Sampling

Sample Collection and Field Measurements

As in fixed-site sampling, the number and frequency of samples collected and the scheduling of sample

collection in SRS is important for planning and data interpretation. Sample collection in SRS must be

consistent and unbiased over time within each sampling episode, across sampling strata, and among LTRMP

field stations. The partitioning of effort among strata within each SRS episode (Table B-1) reflects an

emphasis on off-channel areas and a recognition that these areas are probably more spatially variable than

the main channel.

During 1993–96, Pool 26 Field Station personnel participated in 13 SRS episodes. In these 13 episodes,

the field team visited about 1,450 sites (Appendix B) and collected about 1,400 grab samples for chemical

analyses. All of these were analyzed for chlorophyll a and suspended solids, but in accord with the design

for SRS, about half of the samples were also analyzed for nitrogen and phosphorus species.

The total number of sites sampled in each episode and stratum is relatively uniform across the period of

record (Table B-2). The flood of 1993 prevented the Pool 26 Field Station from conducting SRS in spring

of that year, and winter 1994 showed significantly lower sample numbers because of hazardous weather and

unsafe ice conditions that prohibited safe field operations for much of this episode. 

Although SRS by the Pool 26 field team has conformed to the general LTRMP design, some minor

adjustments are needed. The distribution of SRS times across the period of record (Figure D-5) shows no

obvious seasonal pattern and, for most strata, no significant linear trend in sampling times over the years

(P > 0.05). However, sampling times in Swan Lake and the impounded area exhibit a slow increase over time

(4–6 minutes per episode). The increase in Swan Lake (about 6 minutes per episode) is statistically

significant (P = 0.01), whereas that in the impounded area (about 4 minutes per episode) is marginal

(P = 0.07). As with fixed-site sampling, SRS has been consistently skewed, with the bulk of samples

collected before noon. A tendency to sample the main channel and impounded strata later in the day than

other strata is also evident. The sampling protocol is being reviewed to determine whether the distribution

of sampling times and strata over the course of a day can be improved.

Stratified Random Sampling Data

The SRS provides an unbiased estimate of conditions within each sampling stratum during each of four

quarterly episodes per year. Seasonality, interannual variations, and long-term trends within each stratum can

be assessed with summaries of these data (Appendix F); however, some of the most valuable applications

for these data require analyses that are beyond the scope of this report. For example, the SRS provides

statistically valid estimates of the extent or frequency of limnological conditions in combination (e.g., to meet

the temperature, dissolved oxygen, and velocity requirements of overwintering fish); this information is being

used to address changing relations among limnological variables over time, differences among the sampling
16

strata, and habitat availability and suitability in the Upper Mississippi River ecosystem (Fischer et al. 1997;

Soballe et al. 1997).

The data collected by the Pool 26 field team in SRS capture long-term patterns in this reach of the river

and document significant differences among the sampling strata (aquatic areas). The contiguous backwater

stratum has higher turbidity, volatile suspended solids, and fluorometric chlorophyll a than the main and side

channels. Mean ammonium nitrogen, temperature, and dissolved oxygen levels are not strikingly different

in the contiguous backwaters, but are much more variable than in the main or side channel strata. This

variability may be due in part to the shallowness and general lack of current in the backwaters, which makes

them more easily heated and cooled. Total nitrogen and nitrate–nitrite nitrogen tend to be lower in the

backwaters than in the main and side channels, suggesting that the backwater areas may be either sinks for

nitrogen or diluted sources of nitrogen (Figure F-1a). 

The SRS data for Swan Lake show a slight decline in dissolved oxygen and slight rises in turbidity,

suspended solids, and volatile suspended solids (not plotted) in the lake (Figures F-2, F-3, F-6, and F-7).

Monitoring will be required to determine if these trends will continue after completion of the Swan Lake

Habitat project now under construction. This HREP includes a levee designed to isolate Swan Lake from the

Illinois River and a series of artificial islands designed to reduce wind-fetch and sediment resuspension.

The large flood of 1993 prevented the Pool 26 field team from conducting SRS in spring and summer of

that year. Consequently, these data (Appendix F) do not indicate the decline in nitrogen concentrations from

1993 to 1996 as clearly as the fixed-site data. However, they do demonstrate a spring–summer peak in total

nitrogen, nitrate–nitrite nitrogen, turbidity, total suspended solids, fluorometric chlorophyll a, and volatile

suspended solids (not plotted) in the main channel that is typical of most years (Figures F-6, F-7, F-8, F-9,

and F-13). 

The pronounced seasonality in chlorophyll a parallels that of volatile suspended solids, suggesting that

algae may contribute significantly to the total organic particulate material in this reach, even though the

majority of suspended material is inorganic (Figure F-7). Although lower concentrations of chlorophyll a

and volatile suspended solids are typical in winter, these levels are still significant (mean fluorometric

chlorophyll a = 5–7 :g/L; mean volatile suspend solids = 3–6 mg/L), suggesting that the Mississippi River

produces or transports significant quantities of algae during winter (Table F-1).

The strong seasonality of dissolved oxygen concentration is driven primarily by water temperature, and

the effect of phytoplankton production on dissolved oxygen is not readily apparent without further analysis.

Dissolved oxygen concentration and fluorometric chlorophyll a are more variable in contiguous backwaters

than in other strata, consistent with a relation between them.

Summary and Recommendations

In this report, we document 4 years of LTRMP monitoring (1993–96) by the Pool 26 Field Station at

Brighton, Illinois, and provide basic graphic and tabular summaries of the collected data. The field team

completed about 1,700 visits to fixed sampling sites and 1,450 visits to stratified random sites from 1993

through 1996. This period was marked by several important events, including the redesign of the monitoring

network and the updating of field equipment in 1993, record flooding in spring and summer 1993, severe

weather in winter 1994 that limited sampling, and the initiation of a QA/QC program in 1995.
17

The monitoring data show that this reach of the Upper Mississippi River is turbid, has near-saturated

dissolved oxygen concentrations at most locations throughout most of the year (near midday), and has high

concentrations of plant nutrients (particularly nitrogen). The data show decreases in total nitrogen

concentrations and nitrate–nitrite nitrogen following the large flood of 1993. The Swan Lake sampling

stratum had a slight decline in dissolved oxygen concentration and slight increases in turbidity, suspended

solids, and volatile suspended solids over this period.

The data show that the Illinois River is a significant source of nutrients and sediment to this reach. The

data also document the character of the Missouri River, which tends to have elevated phosphorus, but

relatively low nitrogen concentrations. In addition, the Missouri River has higher turbidity, suspended solids,

and silicate concentrations than the Mississippi River.

Contiguous backwaters are unique among the sampling strata, with higher turbidity, volatile suspended

solids, and fluorometric chlorophyll a, and lower total nitrogen and nitrate–nitrite nitrogen than in the main

and side channels. Ammonium nitrogen, temperature, and dissolved oxygen were more variable in contiguous

backwaters than in other sampling strata.

Seasonal patterns were exhibited by total nitrogen, nitrate–nitrite nitrogen, turbidity, total suspended

solids, fluorometric chlorophyll a, and volatile suspended solids, which peaked in the main channel in

spring–summer. Dissolved oxygen concentration also showed pronounced seasonality that paralleled

temperature.

The data indicate that continued monitoring will be required to detect long-term trends or assess the

spatial distribution of habitat over time and to adequately measure the long-term factors that control water

quality in the Mississippi River and its major tributaries in the Pool 26 vicinity.

References

American Public Health Association, American Water Works Association, and Water Environment

Federation (APHA). 1992. Standard methods for the examination of water and wastewater. 18th edition,

American Public Health Association, Washington, D.C. 981 pp. + 6 plates.

Fischer, J. R., D. M. Soballe, and J. T. Rogala. 1997. Factors affecting fish habitat during periods of ice

cover on the Upper Mississippi River. Fifty-ninth Annual Midwest Fish and Wildlife Conference,

Milwaukee, Wisconsin, December 6–10, 1997.

Jackson, G. A., C. E. Korschgen, P. A. Thiel, J. M. Besser, D. W. Steffeck, and M. H. Bockenhauer. 1981.

A long-term resource monitoring plan for the Upper Mississippi River System. Volume 1. Upper

Mississippi River Basin Commission, Bloomington, Minnesota. 384 pp. 

Lubinski, K. S., and J. L. Rasmussen. 1988. Procedures Manual of the Long Term Resource Monitoring

Program for the Upper Mississippi River System. U.S. Fish and Wildlife Service, Environmental

Management Technical Center, Onalaska, Wisconsin. EMTC 88-03. 216 pp. (NTIS # PB94-145885)

Owens, T., and J. J. Ruhser. 1996. Long Term Resource Monitoring Program standard operating procedures:

Aquatic areas database production. National Biological Service, Environmental Management Technical

Center, Onalaska, Wisconsin, March 1996. LTRMP 95-P008-6. 4 pp. + Appendix (NTIS #PB96-172267)
18

Soballe, D. M., and J. Fischer. 2003. Long Term Resource Monitoring Program procedures: Water quality

monitoring. U.S. Geological Survey, Upper Midwest Environmental Sciences Center, Onalaska,

Wisconsin. In press.

Soballe, D. M., J. T. Rogala, and J. R. Fischer. 1997. Finding suitable winter habitat for fish in shallow

impoundments of the Upper Mississippi River. Seventeenth Annual Symposium of the North American

Lake Management Society, Houston, Texas, December 2–6, 1997.

U.S. Fish and Wildlife Service. 1993. Operating plan for the Upper Mississippi River System Long Term

Resource Monitoring Program. Environmental Management Technical Center, Onalaska, Wisconsin,

Revised September 1993. EMTC 91-P002R. 179 pp. (NTIS #PB94-160199)

Vannote, R. L., G. W. Minshall, K. W. Cummins, J. R. Sedell, and C. E. Cushing. 1980. The river continuum

concept. Canadian Journal of Fisheries and Aquatic Sciences 37:130–137.

Wilcox, D. B. 1993. An aquatic habitat classification system for the Upper Mississippi River System.

U.S. Fish and Wildlife Service, Environmental Management Technical Center, Onalaska, Wisconsin,

May 1993. EMTC 93-T003. 9 pp. + Appendix A (NTIS #PB93-208981)

Wlosinski, J. H., D. E. Hansen, and S. R. Hagedorn. 1995. Long Term Resource Monitoring Program

procedures: Water surface elevation and discharge. National Biological Service, Environmental

Management Technical Center, Onalaska, Wisconsin, August 1995. LTRMP 95-P002-4.

9 pp. + Appendixes A–O.
A-1

Appendix A. Fixed-site Sampling Sites: January 1993–December 1996

In Appendix A, we provide information on the sample collection sites used from January 1993 through

December 1996. In some instances, sites not used during this period have been included for reference. The

site description tables provide additional information on the locations and are keyed to the site map. The site

lists are provided in three formats to allow easy cross referencing: (1) by map identifier (north–south, then

east–west), (2) in alphabetical order, and (3) by habitat class. The period of record for each site is also

portrayed graphically (Figure A-5) so that the duration of and interruptions in the record can be easily

visualized.

Location codes (seven characters) used for routine fixed-site sampling are based on the distance upstream

from the river mouth or major confluence (river miles and tenths) and on the relative left-to-right (facing

upstream) location of the site between the horizontal limits of the geological–historical floodplain. Sites on

the Mississippi and Illinois River main stems use a single-letter prefix (M or I, respectively), whereas

tributaries and Missouri River sites use a two-letter prefix (Table A-5). The left-to-right location of a site is

indicated by a suffix between A and Z. When tributary sites are sampled in midstream, they are assigned the

suffix M without regard to position in the floodplain. Locations near the left or right bank (facing upstream)

are indicated with an A or Z, respectively.

Habitat classes (Table A-4) are assigned to all Long Term Resource Monitoring Program sampling

locations used in fixed-site monitoring. Although these classes convey significant information about the site,

the fixed sites are subjectively chosen and cannot be assumed to represent the associated habitat classes (see

stratified random sampling, Appendix B).
A-2

Table A-1. Long Term Resource Monitoring Program fixed-site water quality sampling locations keyed to map codes with

associated period of record from 1993 through 1996, habitat class, Universal Transverse Mercator (UTM) Coordinates

(zone 15, meters), and the number of sampling visits to the site.

Location

code

Map

identification Period of record

Habitat

classa

UTM

Site visits

Easting Northing 1993–1996

M241.4K 1 10/05/90–12/13/96 MC 700637 4319647 92

I007.0W 2 08/05/88–12/12/96 MC 712523 4315756 94

M219.4U 3 10/18/90–04/28/93 MC 720533 4315208 16

BC04.6M 4 05/03/93–04/11/94 TRIB 695569 4315141 16

M237.4T 5 07/29/88–04/28/93 MC 701569 4313786 16

I005.8K 6 08/04/88–04/28/93 BWC 714649 4313556 16

I005.7M 7 08/04/88–12/12/96 BWC 714703 4313347 61

PI00.2M 8 05/04/93–12/30/96 TRIB 735030 4313310 80

M212.4X 9 08/03/88–04/27/93 MC 731177 4313146 16

M237.2G 10 07/29/88–12/13/96 BWC 701683 4312554 85

M211.2P 11 07/19/88–04/27/93 MC 731978 4311972 16

M235.6J 12 07/29/88–04/28/93 MC 702973 4310861 16

CU11.6M 13 05/03/93–11/15/96 TRIB 695163 4310565 63

M235.5D 14 03/22/90–09/20/96 BWI 702472 4310285 70

M206.1T 15 08/04/88–12/31/96 BWI 739967 4309408 52

M206.0S 16 07/19/88–12/09/96 BWC 739884 4309158 88

M205.8K 17 07/27/88–04/05/93 BWI 739745 4308992 4

M224.2S 18 07/29/88–04/28/93 SC 716523 4308859 16

M203.5R 19 07/19/88–12/30/96 IMP 742896 4307339 76

M202.6T 20 05/30/95–12/30/96 MC 744053 4307283 40

M203.5Q 21 07/28/88–04/27/93 IMP 742887 4307244 16

M202.9Q 22 09/12/91–04/05/93 BWI 743661 4306774 4

M202.9N 23 09/12/91–04/05/93 BWI 743418 4306696 4

M202.2V 24 07/19/88–04/27/93 IMP 744990 4306563 16

PE01.8M 25 05/06/93–12/11/96 TRIB 703159 4306271 76

M202.2R 26 02/14/90–04/27/93 IMP-L 744769 4306204 16

M202.2N 27 02/14/90–12/30/96 IMP-L 743830 4306157 93

M201.7Q 28 06/03/93–12/30/96 IMP-L 744970 4305854 77

WD00.2M 29 05/05/93–12/10/96 TRIB 749105 4305319 50

DC01.0M 30 05/03/93–12/11/96 TRIB 712694 4303092 79

M196.9Q 31 05/05/93–12/31/96 MC 750631 4302053 83

MO02.0X 32 05/05/93–12/31/96 TRIB 748277 4301655 82

CA00.4M 33 05/05/93–12/31/96 TRIB 751328 4298975 78

M193.2F 34 05/05/93–12/31/96 MC 748748 4297372 82

a

See Table A-4 for habitat class descriptions.
A-3

Table A-2. Long Term Resource Monitoring Program fixed-site water quality sampling sites sorted by location code with

associated period of record from 1993 through 1996, habitat class, Universal Transverse Mercator (UTM) Coordinates

(zone 15, meters), and number of sampling visits to the site.

Location

code

Map

identification Period of record

Habitat

classa

UTM

Site visits

Easting Northing 1993–1996

BC04.6M 4 05/03/93–04/11/94 TRIB 695569 4315141 16

CA00.4M 33 05/05/93–12/31/96 TRIB 751328 4298975 78

CU11.6M 13 05/03/93–11/15/96 TRIB 695163 4310565 63

DC01.0M 30 05/03/93–12/11/96 TRIB 712694 4303092 79

I005.7M 7 08/04/88–12/12/96 BWC 714703 4313347 61

I005.8K 6 08/04/88–04/28/93 BWC 714649 4313556 16

I007.0W 2 08/05/88–12/12/96 MC 712523 4315756 94

M193.2F 34 05/05/93–12/31/96 MC 748748 4297372 82

M196.9Q 31 05/05/93–12/31/96 MC 750631 4302053 83

M201.7Q 28 06/03/93–12/30/96 IMP–L 744970 4305854 77

M202.2N 27 02/14/90–12/30/96 IMP–L 743830 4306157 93

M202.2R 26 02/14/90–04/27/93 IMP–L 744769 4306204 16

M202.2V 24 07/19/88–04/27/93 IMP 744990 4306563 16

M202.6T 20 05/30/95–12/30/96 MC 744053 4307283 40

M202.9N 23 09/12/91–04/05/93 BWI 743418 4306696 4

M202.9Q 22 09/12/91–04/05/93 BWI 743661 4306774 4

M203.5Q 21 07/28/88–04/27/93 IMP 742887 4307244 16

M203.5R 19 07/19/88–12/30/96 IMP 742896 4307339 76

M205.8K 17 07/27/88–04/05/93 BWI 739745 4308992 4

M206.0S 16 07/19/88–12/09/96 BWC 739884 4309158 88

M206.1T 15 08/04/88–12/31/96 BWI 739967 4309408 52

M211.2P 11 07/19/88–04/27/93 MC 731978 4311972 16

M212.4X 9 08/03/88–04/27/93 MC 731177 4313146 16

M219.4U 3 10/18/90–04/28/93 MC 720533 4315208 16

M224.2S 18 07/29/88–04/28/93 SC 716523 4308859 16

M235.5D 14 03/22/90–09/20/96 BWI 702472 4310285 70

M235.6J 12 07/29/88–04/28/93 MC 702973 4310861 16

M237.2G 10 07/29/88–12/13/96 BWC 701683 4312554 85

M237.4T 5 07/29/88–04/28/93 MC 701569 4313786 16

M241.4K 1 10/05/90–12/13/96 MC 700637 4319647 92

MO02.0X 32 05/05/93–12/31/96 TRIB 748277 4301655 82

PE01.8M 25 05/06/93–12/11/96 TRIB 703159 4306271 76

PI00.2M 8 05/04/93–12/30/96 TRIB 735030 4313310 80

WD00.2M 29 05/05/93–12/10/96 TRIB 749105 4305319 50

a

See Table A-4 for habitat class descriptions.
A-4

Table A-3. Long Term Resource Monitoring Program fixed-site water quality sampling locations sorted by habitat class

with associated period of record from 1993 through 1996, habitat class, Universal Transverse Mercator (UTM)

Coordinates (zone 15, meters), and number of sampling visits to the site.

Location

code

Map

identification Period of record

Habitat

classa

UTM

Site visits

Easting Northing 1993–1996

I005.7M 7 08/04/88–12/12/96 BWC 714703 4313347 61

I005.8K 6 08/04/88–04/28/93 BWC 714649 4313556 16

M206.0S 16 07/19/88–12/09/96 BWC 739884 4309158 88

M237.2G 10 07/29/88–12/13/96 BWC 701683 4312554 85

M202.9N 23 09/12/91–04/05/93 BWI 743418 4306696 4

M202.9Q 22 09/12/91–04/05/93 BWI 743661 4306774 4

M205.8K 17 07/27/88–04/05/93 BWI 739745 4308992 4

M206.1T 15 08/04/88–12/31/96 BWI 739967 4309408 52

M235.5D 14 03/22/90–09/20/96 BWI 702472 4310285 70

M202.2V 24 07/19/88–04/27/93 IMP 744990 4306563 16

M203.5Q 21 07/28/88–04/27/93 IMP 742887 4307244 16

M203.5R 19 07/19/88–12/30/96 IMP 742896 4307339 76

M201.7Q 28 06/03/93–12/30/96 IMP–L 744970 4305854 77

M202.2N 27 02/14/90–12/30/96 IMP–L 743830 4306157 93

M202.2R 26 02/14/90–04/27/93 IMP–L 744769 4306204 16

I007.0W 2 08/05/88–12/12/96 MC 712523 4315756 94

M193.2F 34 05/05/93–12/31/96 MC 748748 4297372 82

M196.9Q 31 05/05/93–12/31/96 MC 750631 4302053 83

M202.6T 20 05/30/95–12/30/96 MC 744053 4307283 40

M211.2P 11 07/19/88–04/27/93 MC 731978 4311972 16

M212.4X 9 08/03/88–04/27/93 MC 731177 4313146 16

M219.4U 3 10/18/90–04/28/93 MC 720533 4315208 16

M235.6J 12 07/29/88–04/28/93 MC 702973 4310861 16

M237.4T 5 07/29/88–04/28/93 MC 701569 4313786 16

M241.4K 1 10/05/90–12/13/96 MC 700637 4319647 92

M224.2S 18 07/29/88–04/28/93 SC 716523 4308859 16

BC04.6M 4 05/03/93–04/11/94 TRIB 695569 4315141 16

CA00.4M 33 05/05/93–12/31/96 TRIB 751328 4298975 78

CU11.6M 13 05/03/93–11/15/96 TRIB 695163 4310565 63

DC01.0M 30 05/03/93–12/11/96 TRIB 712694 4303092 79

MO02.0X 32 05/05/93–12/31/96 TRIB 748277 4301655 82

PE01.8M 25 05/06/93–12/11/96 TRIB 703159 4306271 76

PI00.2M 8 05/04/93–12/30/96 TRIB 735030 4313310 80

WD00.2M 29 05/05/93–12/10/96 TRIB 749105 4305319 50

a

See Table A-4 for habitat class descriptions.
A-5

Table A-4. Habitat classes used in fixed-site water quality sampling. Previous habitat classes refer to categories used

from 1988 through 1993 and are now combined within each of the present habitat classes.

Present

habitat class

designator Previous habitat designators included in present class Habitat class description

BWC BWC, BWC-O, BWC-V Contiguous backwaters

BWI BWI, BWI-O, BWI-V Isolated backwaters

SC SC, SCB, SCT, SCU Side channels

IMP IMP-O, IMP-V Impounded areas

IMP-L IMP-L Lakes—Swan or Pepin

MC MC, CTR, CBU, CBW, TW, TWB, TWBU, TWR-O, TWW Main channel

TRIB TRIB, TRM Tributary

Table A-5. Abbreviations used to designate fixed-site sampling locations in the Long Term Resource Monitoring Program

(LTRMP). Not all streams in this list have been sampled by the LTRMP. The Mackinaw, Spoon, and Sangamon Rivers

are all tributaries to the Illinois River. Each site identifier includes the distance (in miles) above the tributary mouth (xx.x)

and the relative location (A–Z) of the sampling site between the left and right (facing upstream) limits of the floodplain.

Site identifier Tributary name

APxx.xM Apple River, Missouri

ALxx.xM Apple River, Illinois

BCxx.xM Bob's Creek, Missouri

BFxx.xM Buffalo River, Wisconsin

BKxx.xM Black River, Wisconsin

BMxx.xM Big Muddy River, Illinois 

BXxx.xM Bad Axe River, Wisconsin

CAxx.xM Cahokia Creek, Illinois

CCxx.xM Coon Creek, Wisconsin

CFxx.xM Catfish Creek, Iowa

CHxx.xM Chippewa River, Wisconsin

CNxx.xM Cannon River, Minnesota

CRxx.xM Cache River, Illinois

CUxx.xM Cuivre River, Missouri

DCxx.xM Dardenne Creek, Missouri

DMxx.xM Des Moines River, Iowa

ERxx.xM Elk River, Iowa

HDxx.xM Headwaters Diversion, Missouri (formerly Little River, LRxx.xM)

Ixxx.xZ Illinois River, Illinois

IWxx.xM Iowa River, Iowa

LMxx.xM LaMoines River, Illinois

LRxx.xM Little River, Missouri (now Headwaters Diversion, HDxx.xM)
Table A-5. Continued.

Site identifier Tributary name

A-6

LXxx.xM La Crosse River, Wisconsin

Mxxx.xZ Mississippi River (main stem) 

MCxx.xM Mill Creek, Iowa

MKxx.xM Mackinaw River, Illinois

MOxx.xM Missouri River, Missouri

MQxx.xM Maquoketa River, Iowa

PExx.xM Peruque Creek, Missouri 

PIxx.xM Piasa Creek, Illinois

PRxx.xM Plum River, Illinois

QVxx.xM Quiver Creek, Illinois

Rxxx.xM Root River, Minnesota

RCxx.xM Rush Creek, Illinois

Sxxx.xM Spoon River, Illinois

SGxx.xM Sangamon River, Illinois

SKxx.xM Skunk River, Iowa 

SXxx.xM St. Croix River, Minnesota/Wisconsin

UIxx.xM Upper Iowa River, Iowa

VMxx.xM Vermillion River, Minnesota

WDxx.xM Wood River, Illinois

WPxx.xM Wapsipinicon River, Iowa

WSxx.xM Wisconsin River, Wisconsin

WWxx.xM Whitewater River, Minnesota

YLxx.xM Yellow River, Iowa

ZMxx.xM Zumbro River, Minnesota
A-7

Figure A-1. Fixed-site sampling locations in the Pool 26 study area.
A-8

Figure A-2. Sampling dates from January 1993 through December 1996 at each of the fixed sites monitored by the

Pool 26 Field Station.
B-1

Appendix B. Stratified Random Sampling Sites: January 1993–December 1996

Randomly selected sites are used in stratified random sampling (SRS) to provide an unbiased

representation of sampling strata (and entire study areas) within each Long Term Resource Monitoring

Program study reach. Individual sites are generally not resampled in subsequent SRS episodes. Information

from an individual site is not intended to be interpreted in isolation, as it is only a single random

measurement from all the locations within a stratum during a specific episode. When pooled together,

multiple measurements (sites) from each stratum provide a statistically reliable sample of the episode and

the study reach.

Unlike the fixed-site location maps (Appendix A), the maps provided for SRS do not show the individual

sampling locations, but rather the sampling strata within the reach. This approach allows a legible portrayal

and de-emphasizes the individual identities of SRS locations.

The tables in Appendix B show the allocation of sampling effort across the sampling strata and across the

14 SRS episodes within the 1993–96 period.

Table B-1. Sampling strata and design allocation of sampling effort for water quality stratified random sampling in the

vicinity of the Pool 26 Field Station. Total area of the study reach is greater than the total area included within the

sampling strata because of inaccessible areas that are excluded from sampling.

Sampling

stratum

Area within

the stratum

(ha)

Fraction of

study area

within the

stratum

 (%)

Number of

potential

sampling sites

in the stratuma

Number of

sites

assigned

Fraction of

stratum

sampled

(%)

Fraction

of total

effort

(%)

Main channel 4,860 52 1,215 20 1.6 17

Side channel 1,496 16 5,983 42 0.7 35

Backwater 415 4 1,658 29 1.7 24

Lake 948 237 15 6.3 12

Impounded 176 2 44 15 34.1 12

Isolated 580 6 145 0 0.0 0

Totalb 9,346 81 9,282 121 1.3 100

a

Total potential sites reflects a 200-m grid in most strata but a 50-m grid in side channels and backwaters.

b

Total area refers to the entire pool or study reach and is greater than the sum of areas within the sampling strata.
B-2

Table B-2. Sampling dates and sampling activity of the Pool 26 Field Station in each stratified random sampling episode

from 1993 through 1996.

Sampling period Number of samples collected/sites visited

Episode

Start

date

End

date Total

Main

channel

Side

channel

Contiguous

backwater Lake Impoundment Isolated

Fall 93 10/19/93 10/29/93 168/111 21/20 69/41 34/20 18/15 26/15 —

Winter 94 01/26/94 02/18/94 87/71 18/18 36/29 13/11 5/5 15/8 —

Spring 94 04/25/94 05/08/94 187/120 20/20 69/42 43/28 28/15 27/15 —

Summer 94 07/26/94 08/08/94 157/106 22/20 71/42 35/29 NA 29/15 —

Fall 94 10/12/94 10/24/94 153/121 21/20 58/42 33/29 15/15 26/15 —

Winter 95 01/30/95 02/10/95 118/99 20/20 45/41 27/23 NA 26/15 —

Spring 95 04/24/95 05/05/95 166/121 20/20 45/42 45/29 30/15 26/15 —

Summer 95 07/24/95 08/04/95 165/120 20/20 65/41 36/29 16/15 28/15 —

Fall 95 10/10/95 10/20/95 158/121 20/20 63/42 30/29 16/15 29/15 —

Winter 96 01/29/96 02/16/96 139/106 21/20 58/37 36/34 NA 24/15 —

Spring 96 04/22/96 05/03/96 165/121 20/20 57/42 38/29 25/15 25/15 —

Summer 96 07/23/96 08/01/96 149/121 20/20 62/42 31/29 15/15 21/15 —

Fall 96 10/07/96 10/11/96 162/106 20/20 80/42 34/29 NA 28/15 —
B-3

Figure B-1. Long Term Resource Monitoring Program sampling strata used in water quality stratified random sampling

in the vicinity of the Pool 26 Field Station.
C-1

Appendix C. Limnological Parameters Measured in the

Long Term Resource Monitoring Program

Table C-1. Period of record for limnological measurements (laboratory and in situ) performed by Long Term Resource

Monitoring Program field teams from 1988 through 1996.

Parameter 1988 1989 1990 1991 1992 1993–1996

Water temperature $$$$$$ $$$$$$ $$$$$$ $$$$$$ $$$$$$ $$$$$$

Dissolved oxygen $$$$$$ $$$$$$ $$$$$$ $$$$$$ $$$$$$ $$$$$$

Conductivity $$$$$$ $$$$$$ $$$$$$ $$$$$$ $$$$$$ $$$$$$

pH June $$ $$$$$$ $$$$$$

Turbidity $$$$$$ $$$$$$ $$$$$$ $$$$$$ $$$$$$ $$$$$$

Secchi depth $$$$$$ $$$$$$ $$$$$$ $$$$$$ $$$$$$ $$$$$$

Total suspended solids $$$$$$ $$$$$$ $$$$$$

Volatile suspended solids $$$$$$ $$$$$$ $$$$$$

Chlorophyll a June $$ $$$$$$ $$$$$$

Total phosphorus June $$ $$$$$$ $$$$$$

Soluble reactive phosphorus June $$ $$$$$$ $$$$$$

Total soluble phosphorus June $$ $$$$$$ $$$ Apr 93

Total nitrogen June $$ $$$$$$ $$$$$$

Total soluble nitrogen June $$ $$$$$$ $$$ Apr 93

NOx (nitrate–nitrite) June $$ $$$$$$ $$$$$$

NHx (ammonium) June $$ $$$$$$ $$$$$$

Si (silicate) June $$ $$$$$$ $$$$$$

Cl (chloride) June $$ $$$$$$ $$$$$$

Ca (calcium) June $$ $$$$$$ $$$$$$

Mg (magnesium) June $$ $$$$$$ $$$$$$

Na (sodium) June $$ $$$$$$ $$$$$$

K (potassium) June $$ $$$$$$ $$$$$$

Fe (iron) June $$ $$$$$$ $$$ Feb 93

Mn (manganese) June $$ $$$$$$ $$$ Feb 93

Ice and snow $$$$$$ $$$$$$ $$$$$$ $$$$$$ $$$$$$ $$$$$$

Water depth $$$$$$ $$$$$$ $$$$$$ $$$$$$ $$$$$$ $$$$$$

Water velocity $$$$$$ $$$$$$ $$$$$$ $$$$$$ $$$$$$ $$$$$$
C-2

Table C-2. Laboratory measurements performed on limnological samples from 1988 through 1996. Each laboratory

processed samples or parameters between the dates listed. The precision of result reporting is shown in parentheses.

Analytical techniques are described in the procedures manuals for the Waterways Experiment Station (WES)

Environmental Laboratories and by the American Public Health Association et al. (1992).

Parameter and method

Laboratory

WES–Vicksburg WES–Eau Galle UMESCa

Total suspended solids:

Gravimetric/105° C

— June 91–June 93

(1 :g/L)

June 93–Present

(1 :g/L)

Volatile suspended solids:

Gravimetric/550° C

— June 91–June 93

(1 :g/L)

June 93–Present

(1 :g/L)

Chlorophyll a: FluorometricDMSO-acetone extraction

— — June 93–Present

(1 :g/L)

Chlorophyll a:

Spectrophotometric 90% acetone

extraction

— June 91–June 93

(1 :g/L)

June 93–Present

(1 :g/L)

Total phosphorus: Automated/

persulfate/ascorbic acid

— June 91–Jan. 94

(1 :g/L)

Jan. 94–Present

(1 :g/L)

Soluble reactive phosphorus

(H): Automated/H2SO4

preservation, ascorbic acid

June 91–Dec. 93

(1 :g/L)

— —

Soluble reactive phosphorus:

Automated/frozen/ascorbic acid

Jan. 94–Feb. 94

(1 :g/L)

— Feb. 94–Present

(1 :g/L)

Total soluble phosphorus

Automated/persulfate/ascorbic

acid

— June 91–Apr. 93

(1 :g/L)

—

Total nitrogen:

Automated/Devarda's alloy

— June 91–Jan. 94

(0.01 mg/L)

Jan. 94–Present

(0.01 mg/L)

Total soluble nitrogen:

Automated/Devarda's alloy

— June 91–Apr. 93

(0.01 mg/L)

—

Nitrate plus nitrite nitrogen:

Automated Cd reduction, Ion

chromatography 

June 91–Apr. 94

Automated Cd

Reduction

(0.01 mg/L)

— Apr.–June 94

Cd Reduction

June 94–Present

Ion C

(0.01 mg/L)

NHx: Automated salicylate June 91–Feb. 94

(1 :g/L)

— Feb. 94–Present

(1 :g/L)

Dissolved silicate silica:

Automated/molybdate

June 91–Feb. 94

(0.01 mg/L)

— Mar. 94–Present

(0.01 mg/L)

SO4: Ion chromatography — — Jan. 94–Present

(0.1 mg/L)

Dissolved chloride: Automated

Ferro-cyanide, Ion

chromatography

June 91–June 94

Automated FeCN

 (0.1 mg/L)

— June 94–Present

IC

(0.1 mg/L)

Dissolved calcium: Ion

chromatography

— — Jan. 94–Present

(0.1 mg/L)

Dissolved calcium: Atomic

absorption

June 91–Oct. 93

(0.1 mg/L)

— Oct. 93–1 Jan. 94

(0.1 mg/L)
Table C-2. Continued.

Parameter and method

Laboratory

WES–Vicksburg WES–Eau Galle UMESCa

C-3

Dissolved magnesium: Ion

chromatography

Jan. 94–Present

(0.1 mg/L)

Dissolved sodium: Ion

chromatography

Jan. 94–Present

(0.1 mg/L)

Dissolved potassium: Atomic

absorption

June 91–Oct. 93

(0.1 mg/L)

— Oct. 93–Present

(0.1 mg/L)

Dissolved iron: Atomic

absorption

June 91–Apr. 93

(0.01 mg/L)

— —

Dissolved manganese: Atomic

absorption

June 91–Apr. 93

(0.01 mg/L)

— —

a

Upper Midwest Environmental Sciences Center
D-1

Appendix D. Water Quality Sample Collection

Details of sample collection are important to ensure that field activities comply with the monitoring design

and are producing unbiased results. The figures in Appendix D focus on site visits and sample collection

times. Consistent differences in sampling times among sites, over time, or among field stations can introduce

serious bias into measurements influenced by daily cycles (e.g., temperature and dissolved oxygen). Gaps

in the data record can also have important ramifications for data interpretation and are therefore documented

here.

Table D-1. Fixed-site sampling visit exceptions from 1993 through 1996 at the Pool 26 Field Station. Table entries are

keyed to numbered points on Figure D-1.

Figure

code

Begin

date

Site

visits Comment

1 07/12/93 0 1993 flood–no traffic allowed on River 

2 10/25/93 0 Sampling crew misunderstood revised sampling protocol 

3 01/03/94 8 Extreme cold–unsafe to sample

4 01/17/94 6 Extreme cold–unsafe to sample

5 01/31/94 0 Sampling crew misunderstood revised sampling protocol

6 04/25/94 0 Sampling crew misunderstood revised sampling protocol

7 05/16/94 2 Sampling for training only

8 08/01/94 0 Sampling crew misunderstood revised sampling protocol 

9 10/17/94 1 Site sampled late (Sunday)

10 11/21/94 0 Lack of personnel to sample 

11 02/06/95 9 Unsafe ice conditions

12 05/29/95 1 Could not access most sites because of flooding

13 06/05/95 1 Could not access most sites because of flooding

14 02/05/96 9 Unsafe ice conditions

15 12/23/96 0 Lack of personnel to sample

16 12/30/96 10 Unsafe ice conditions
D-2

Figure D-1. Number of weekly fixed-site visits from January 1993 through December 1996 by the Pool 26 Field Station.

Numbered points are weeks that differ by more than one standard deviation from the mean site visits per week and are

described in Table D-1.
D-3

Figure D-2. Distribution of sample collection times at fixed sites from 1993 through 1996. Each bar is labeled with the

number of site visits within each hourly interval.
D-4

Figure D-3. Trend in fixed-site sample collection times by quarter, from 1993 through 1996. The midpoint (median) for

each quarter is joined by a solid line. The box extending above and below the median denotes the 90th and 10th

percentiles, respectively. The vertical line extends above and below the box to the maximum and minimum values for

the quarter.
D-5

Figure D-4. Distribution of fixed sites by median sampling time at each site from 1993 through 1996.
D-6

Figure D-5. Water quality sample collection times in each sampling stratum during each episode of stratified random

sampling from 1993 through 1996. The midpoints (median) of the episodes are joined by a solid line. The box extending

above and below the median denotes the 90th and 10th percentiles, respectively. The vertical line extends above and

below each box to the maximum and minimum values for the episode. 
E-1

Appendix E. Fixed-site Sampling Data: January 1993–December 1996

In Appendix E, we summarize the fixed-site monitoring data in both tabular and graphic forms. The

tables contain annual statistics for each fixed site divided into two parameter groups: (1) physical and

biological measurements (Table E-1), and (2) chemical data (major anions, cations, and plant nutrients;

Table E-2). Within each parameter group, the data are divided by sampling depth into three groups (surface,

middepth, and bottom). Chemical measurements are typically collected only at the surface and near the

bottom. The majority of all measurement are in the near-surface category. Refer to Appendix A for

descriptions and locations of the individual sampling sites. Sites with less than five visits during the 1993–96

period are excluded from these summaries.

The figures (E-1 and E-2) of the fixed-site data are in two formats. For sampling on the Mississippi

(or Illinois) River main stems, the figures generally include separate plots of monthly means from main

channel and impounded sites near the upstream and downstream ends of the reach or pool (where available).

For tributary sampling, only a single plot is provided. Unlike the summary tables, these figures combine data

from all sampling depths.

Data that have been flagged as questionable in the Long Term Resource Monitoring Program

database are excluded from this summary. Values that are below detection are indicated by the detection limit

preceded by a negative sign. Below-detection values are included in the determination of minima, maxima,

and medians, but in the calculation of means and standard deviations, values below detection have been

replaced by a value equal to half the detection limit. The Secchi transparency data in this report do not

include observations where Secchi transparency exceeded the water column depth. High transparency

conditions are thus under represented.
E-2

Table E-1. Annual summaries (1993–1996) of physical measurements at fixed sites grouped into four categories: near-surface (less than or eqmiddepth, near bottom (less than or equal to 0.2 m above the substrate), and miscellaneous depths.

Samplinglocation Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Total

suspend

solids

(mg/L)

1993 Near-surface measurements: 

BC04.6M Mean 0.2 1.32 — — — — — 13.3 8.84 83 458 7.8 — 14 13.4  Median 0.2 1.4 — — — — — 13.1 8.5 84 454 7.8 — 14 12.6  Minimum 0.2 0.3 — — — — — 5.3 7 72 254 7.2 — 10 5.7  Maximum 0.2 2.5 — — — — — 24 11.4 93 655 8.2 — 19 27.4  Std. dev. 0 0.87 — — — — — 6.76 1.56 5.55 109 0.29 — 2.83 6.51 

N obs. 11 11 0 0 0 0 0 11 11 11 11 10 0 11 9 

CA00.4M Mean 0.2 4.92 0 — — — — 15.2 9.1 88 512 8 43.8 29 28.6  Median 0.2 5.35 0 — — — — 17.6 8.35 87 493 8.1 36 25 27.6  Minimum 0.2 1.5 0 — — — — 2 6.2 69 186 7.6 21 15 5.7  Maximum 0.2 8.5 0 — — — — 26.5 12.7 121 762 8.5 100 77 60.4  Std. dev. 0 2.63 0 — — — — 8.08 2.36 14.2 154 0.22 21.6 16.7 17.2 

N obs. 12 12 2 0 0 0 0 12 12 12 12 12 12 12 10 

CU11.6M Mean 0.2 6.3 0 — — — — 14.7 8.03 77 283 7.5 40 61 65.1  Median 0.2 6.3 0 — — — — 15.1 8.05 75 243 7.5 40 54 53.9  Minimum 0.2 6.3 0 — — — — 6 3.7 46 115 7.2 40 10 10.7  Maximum 0.2 6.3 0 — — — — 25.8 11.2 106 582 8.2 40 111 190  Std. dev. 0 — — — — — — 7.41 2.09 15.8 134 0.28 — 36.4 57 

N obs. 12 1 1 0 0 0 0 12 12 12 12 10 1 12 10 

DC01.0M Mean 0.2 2.57 — — — — — 13.1 7.36 67 341 7.7 — 56 71.7  Median 0.2 2 — — — — — 9.3 8 72 319 7.7 — 46 50.8  Minimum 0.2 1.3 — — — — — 6.8 3.4 41 210 7 — 26 18.7  Maximum 0.2 4.9 — — — — — 24 10.4 85 544 8.4 — 88 185  Std. dev. 0 1.37 — — — — — 7.1 2.43 16 107 0.48 — 24.7 62.9 

N obs. 7 7 0 0 0 0 0 7 7 7 7 6 0 7 6 

I005.7M Mean 0.2 2.07 0.08 70.8 7 16 0 11 10.1 89 584 8.1 36.3 40 49.8  Median 0.2 1.4 0.08 90 7 0 0 10 9.8 88 592 8.1 36 36 28.1  Minimum 0.2 0.51 0 5 3 0 0 0.3 5.5 68 301 7.7 8 18 11.6  Maximum 0.2 4.6 0.31 98 12 65 0 26.9 15 133 796 8.7 60 128 211  Std. dev. 0 1.27 0.1 44.2 4.21 32.5 .15 8.64 2.83 14.1 107 0.3 12.2 24.2 60.2 

N obs. 21 21 19 4 4 4 4 21 20 20 21 21 21 21 10 

I005.8K Mean 0.2 1.76 0.07 85 3 0 0 5.83 12.4 99 595 8.2 35.9 45 —  Median 0.2 1.3 0 85 3 0 0 3.8 12 90 595 8.1 38 30 —  Minimum 0.2 0.55 0 75 3 0 0 0.1 8.6 82 454 7.7 11 13 —  Maximum 0.2 4.7 0.24 95 5 0 0 15.2 17.2 148 784 8.7 57 151 —  Std. dev. 0 1.27 0.1 10 1.44 0 0 4.94 2.54 21.1 90.1 0.33 13.9 42.1 — 

N obs. 13 12 10 3 3 3 3 12 11 11 12 12 12 12 0 
E-3

Table E-1. Continued.

Samplinglocation Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Total

suspend

solids

(mg/L)

1993 Near-surface measurements: 

I007.0W Mean 0.2 2.34 0.4 40.3 2 0 0 9.01 10.3 85 619 8.1 26.9 73 68.5  Median 0.2 1.85 0.47 45 1 0 0 5.95 11 88 609 8.1 26.5 49 64.3  Minimum 0.2 0.6 0.1 1 1 0 0 0.2 4.4 55 379 7.3 6 24 16.2  Maximum 0.2 6.71 0.7 75 3 0 0 26.3 14.2 103 1059 9.4 59 320 232  Std. dev. 0 1.52 0.16 37.2 0.87 0 0 8.24 2.98 12.7 144 0.43 12.1 65.8 54.7 

N obs. 28 28 21 3 3 3 3 28 28 28 28 27 28 28 13 

M193.2F Mean 0.2 12.1 — — — — — 15.8 8.49 83 442 8 14.1 226 214  Median 0.2 11.6 — — — — — 17.4 7.65 80 460 8 10 201 139  Minimum 0.2 9.2 — — — — — 4.4 6 69 273 7.2 3 33 36.4  Maximum 0.2 15 — — — — — 25.5 12.2 98 541 8.2 33 600 641  Std. dev. 0 1.99 — — — — — 7.28 2.42 11 87.6 0.26 10.5 185 195 

N obs. 12 11 0 0 0 0 0 12 12 12 12 12 12 12 10 

M196.9Q Mean 0.2 7.87 — — — — — 14.6 9.63 90 404 8.2 29.2 72 75.8  Median 0.2 7.6 — — — — — 16.3 8.15 84 410 8.2 28 52 74.4  Minimum 0.2 4.5 — — — — — 2.5 6.2 74 293 7.2 7 12 16  Maximum 0.2 12.2 — — — — — 25.5 15.9 131 527 8.6 67 210 179  Std. dev. 0 2.65 — — — — — 7.67 3.44 17.2 74.1 0.35 17.2 62.4 49.7 

N obs. 12 11 0 0 0 0 0 12 12 12 12 12 12 12 10 

M201.7Q Mean 0.2 4.86 0.1 — — — — 14.8 9.78 93 371 8 35.6 43 38.6  Median 0.2 4.35 0.06 — — — — 16.4 8.6 88 405 8.2 33 37 25.9  Minimum 0.2 3.7 0 — — — — 4 6.8 81 258 7.2 17 12 19.9  Maximum 0.2 7.4 0.24 — — — — 26.8 14.5 115 492 8.6 65 160 121  Std. dev. 0 1.15 0.12 — — — — 8.53 3.01 12.5 82.8 0.48 13.9 42.5 31.6 

N obs. 10 10 3 0 0 0 0 10 10 10 10 10 10 10 9 

M202.2N Mean 0.2 2.26 0.03 25 3 0 0 10.4 11.3 97 414 8.1 35.9 40 38.5  Median 0.2 1.92 0 25 3 0 0 7.3 10.7 96 424 8.1 39 30 28.7  Minimum 0.2 0.95 0 15 2 0 0 1.7 6.3 76 282 7.1 12 15 20.5  Maximum 0.2 5.8 0.12 35 4 0 0 26.8 17.4 133 544 8.9 75 193 103  Std. dev. 0 1.13 0.04 14.1 1.41 0 0 7.8 3.43 17 78.5 0.39 14 34.8 24.8 

N obs. 25 25 16 2 2 2 2 25 25 25 25 25 25 25 10 

M202.2R Mean 0.2 1.75 0.02 83.3 3 0 0 4.96 13.1 102 433 8.2 37.9 37 23.5  Median 0.2 1.47 0 85 3 0 0 3 13.2 98 404 8 32 36 22.2  Minimum 0.2 0.3 0 75 2 0 0 1.2 9.2 80 333 7.6 22 12 17.8  Maximum 0.2 4.6 0.09 90 3 0 0 12.8 17.6 134 534 9 79 65 30.4  Std. dev. 0 1.19 0.04 7.64 0.58 0 0 3.91 2.38 14.8 83.7 0.39 17.3 19.3 6.39 

N obs. 13 13 12 3 3 3 3 13 13 13 13 13 12 13 3 
E-4

Table E-1. Continued.

Samplinglocation Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Total

suspend

solids

(mg/L)

1993 Near-surface measurements: 

M202.2V Mean 0.2 6.9 0.71 38.5 8 38 1 3.34 12.6 93 448 7.9 25.8 104 68  Median 0.2 6.55 0.6 38.5 8 38 1 1.95 12.7 95 465 7.9 20.5 78 48.6  Minimum 0.2 4 0.3 2 5 0 0 0 8.9 83 309 7.7 4 19 9.6  Maximum 0.2 10.8 1.7 75 12 75 1 12.3 14.9 105 580 8.4 74 337 146  Std. dev. 0 1.68 0.35 51.6 5.3 53 .71 3.62 1.81 6.64 98.2 0.2 18 96.8 70.2 

N obs. 16 16 15 2 2 2 2 16 16 16 16 16 16 16 3 

M203.5Q Mean 0.2 1.14 0.09 70 2 0 0 6.96 10.6 85 370 8.1 19.6 101 104  Median 0.2 1.09 0.08 70 2 0 0 8.1 10 82 328 8 19 76 104  Minimum 0.2 0 0 70 2 0 0 0.2 8.5 79 310 7.8 13 40 104  Maximum 0.2 2.7 0.22 70 2 0 0 13 14.6 100 554 8.6 25 167 104  Std. dev. 0 0.96 0.1 — — — — 5.21 2.46 8.72 103 0.29 4.67 54.8 — 

N obs. 6 6 5 1 1 1 1 5 5 5 5 5 5 5 1 

M203.5R Mean 0.2 1.55 0.19 40 1 0 0 14.3 8.28 78 399 8 24 85 72.8  Median 0.2 1.8 0.23 40 1 0 0 14.8 7.9 81 402 8 19.5 77 61.4  Minimum 0.2 0 0 40 1 0 0 1.8 0.2 2 295 7.8 12 15 24  Maximum 0.2 3.3 0.4 40 1 0 0 26 17 122 574 8.4 42 210 115  Std. dev. 0 0.98 0.12 — — — — 7.54 3.86 26.8 79 0.21 10.5 54.9 40.7 

N obs. 12 13 12 1 1 1 1 12 12 12 12 12 12 12 5 

M206.0S Mean 0.2 1.97 0.13 40 5 0 0 11.5 10.8 99 397 8.3 31.1 52 47.7  Median 0.2 1.2 0 45 5 0 0 11 9.55 92 388 8.3 31 34 40.4  Minimum 0.2 0.4 0 5 5 0 0 2 5.8 74 298 7.8 12 20 12  Maximum 0.2 9.7 0.83 70 6 0 0 27 18.4 146 638 9.4 56 187 112  Std. dev. 0 2.19 0.25 32.8 0.5 0 0 8.17 3.54 23.6 79.5 0.45 12.2 39.6 34.2 

N obs. 19 19 19 3 3 3 3 19 16 16 19 19 19 19 6 

M206.1T Mean 0.2 1.88 0.12 — — — — 16.5 9.59 96 367 8 38.9 49 46.3  Median 0.2 1.8 0 — — — — 17.1 8.7 88 390 8 36 32 35.4  Minimum 0.2 0.5 0 — — — — 7 6.4 73 304 7.5 12 10 18.4  Maximum 0.2 3.3 0.54 — — — — 27.1 15.2 133 422 8.8 64 173 117  Std. dev. 0 0.84 0.2 — — — — 7.3 2.98 21.6 52 0.34 18.1 49.8 35.4 

N obs. 9 9 9 0 0 0 0 9 9 9 9 9 9 9 6 

M211.2P Mean 0.2 2.52 0.26 51.7 11 0 0 3.8 12.3 92 426 8 25.3 86 —  Median 0.2 1.7 0.21 60 7 0 0 2 12.2 92 410 7.9 20 64 —  Minimum 0.2 1.03 0.09 30 6 0 0 0.2 8.4 80 309 7.5 3 22 —  Maximum 0.2 8.04 0.64 65 21 0 0 13 15 105 577 8.8 63 250 —  Std. dev. 0 2.05 0.14 18.9 8.39 0 0 3.81 1.8 7.27 94.6 0.38 16.5 61.7 — 

N obs. 16 15 13 3 3 3 3 15 15 15 15 14 15 15 0 
E-5

Table E-1. Continued.

Samplinglocation Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Total

suspend

solids

(mg/L)

1993 Near-surface measurements: 

M212.4X Mean 0.2 4.98 1.17 33.3 7 0 0 4.15 11.5 88 624 7.9 20.3 85 150  Median 0.2 4.6 1.23 40 4 0 0 2.75 11.9 89 613 8 19 79 42.6  Minimum 0.2 3.3 0.56 5 3 0 0 0.2 8 73 466 7.5 6 34 30.7  Maximum 0.2 9.1 1.58 55 15 0 0 13.8 14.6 103 804 8.4 36 191 378  Std. dev. 0 1.41 0.28 25.7 6.79 0 0 4.27 1.58 7.34 89.8 0.28 8.65 42.4 197 

N obs. 16 15 16 3 3 3 3 16 16 16 16 15 16 16 3 

M219.4U Mean 0.2 5.09 0.77 41.4 3 3 0 2.89 13.2 97 474 7.9 31.1 85 —  Median 0.2 3.91 0.41 60 3 0 0 1.2 13.7 97 543 7.9 27 50 —  Minimum 0.2 2.18 0.19 2 2 0 0 0.1 9.7 85 326 7.5 6 14 —  Maximum 0.2 13.2 1.7 80 7 15 0 13 16 112 617 8.4 64 280 —  Std. dev. 0 3.13 0.58 35.6 1.89 6.71 .13 3.75 1.79 7.51 108 0.27 16.2 76.1 — 

N obs. 16 14 16 5 5 5 5 16 16 16 16 16 16 16 0 

M224.2S Mean 0.2 2.73 0.25 47.5 5 6 0 2.99 12.8 94 463 7.9 28.6 93 —  Median 0.2 2.99 0.24 50 5 0 0 1.35 12.9 95 506 7.9 24.5 67 —  Minimum 0.2 0.62 0.05 10 2 0 0 0.2 9.7 82 311 7.4 8 19 —  Maximum 0.2 8.23 0.49 80 10 20 1 13 14.9 104 607 8.3 60 333 —  Std. dev. 0 2 0.14 30.3 3.46 9.17 0.2 3.71 1.62 7.06 108 0.23 17.3 83 — 

N obs. 16 15 16 6 6 6 6 16 16 16 16 16 16 16 0 

M235.5D Mean 0.2 2.98 0.12 100 1 0 0 12.9 8.92 82 345 8 31 55 52.4  Median 0.2 3.4 0.16 100 1 0 0 10 8.4 79 379 8 28 42 42.8  Minimum 0.2 1 0 100 1 0 0 3.9 6 65 223 7.2 9 23 17.8  Maximum 0.2 4.9 0.26 100 1 0 0 24.6 12.1 107 445 9 52 200 145  Std. dev. 0 1.36 0.11 — — — — 7.6 1.99 10.9 86.9 0.55 10.7 45.3 40.4 

N obs. 13 13 11 1 1 1 1 13 13 13 13 11 13 13 8 

M235.6J Mean 0.2 3.73 0.64 4.75 3 0 0 3.06 13.3 98 478 8 34.8 85 —  Median 0.2 3.07 0.57 5 3 0 0 1.45 13.5 98 543 8 32 50 —  Minimum 0.2 1.7 0.26 3 1 0 0 0.2 9.9 90 326 7.3 7 11 —  Maximum 0.2 7.93 1.33 6 7 0 0 12.9 15.7 110 613 8.5 72 333 —  Std. dev. 0 1.89 0.3 1.26 2.56 0 0 3.7 1.61 5.71 108 0.3 20.1 89 — 

N obs. 16 16 16 4 4 4 4 16 16 16 16 15 16 16 0 

M237.2G Mean 0.2 3.87 0.6 — — — — 9.97 10.8 92 396 8.2 28 161 76.5  Median 0.2 4 0.71 — — — — 7.7 11.9 92 392 8 22 65 78.9  Minimum 0.2 1.5 0 — — — — 0.9 6.6 77 194 7.5 2 11 11.4  Maximum 0.2 6.4 1.03 — — — — 24.8 15 121 607 10 80 1985 183  Std. dev. 0 1.59 0.37 — — — — 7.91 2.61 10.3 92.8 0.64 18.1 412 54.7 

N obs. 23 23 22 0 0 0 0 23 23 23 23 21 23 22 12 
E-6

Table E-1. Continued.

Samplinglocation Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Total

suspend

solids

(mg/L)

1993 Near-surface measurements: 

M237.4T Mean 0.2 3.69 0.65 21.6 4 16 0 3.09 12.7 94 460 7.9 29.9 84 —  Median 0.2 3.07 0.54 10 3 0 0 1.65 13.2 95 486 7.9 24.5 62 —  Minimum 0.2 1.6 0.07 3 1 0 0 0.2 9.6 83 316 7.5 6 15 —  Maximum 0.2 6.1 1.39 80 9 80 1 13 14.7 106 603 8.4 63 241 —  Std. dev. 0 1.53 0.42 32.8 3.42 35.8 .45 3.72 1.42 6.06 95.2 0.26 17.3 72.7 — 

N obs. 16 15 16 5 5 5 5 16 16 16 16 15 16 15 0 

M241.4K Mean 0.2 7.79 0.19 29.5 3 0 0 8.05 12 97 456 8.1 32.9 59 74.3  Median 0.2 7.8 0.15 10.5 2 0 0 3.5 12.3 98 449 8.1 25 53 64.7  Minimum 0.2 1.5 0.05 2 1 0 0 0.3 6.6 81 294 7.6 9 9 14  Maximum 0.2 14.6 0.44 95 7 0 0 25.1 15.8 120 612 9.3 67 210 208  Std. dev. 0 3.27 0.13 44 2.84 0 0 8.41 2.98 9.74 99.2 0.4 18.7 48.3 57.8 

N obs. 27 27 15 4 4 4 4 27 27 27 27 25 27 26 13 

MO02.0X Mean 0.2 9.65 1.77 — — — — 15.6 8.44 82 435 7.9 13.3 245 207  Median 0.2 8.8 1.77 — — — — 17.2 8.1 84 461 8 10 217 146  Minimum 0.2 6.1 1.39 — — — — 4 5.9 69 274 7.1 4 37 32.9  Maximum 0.2 14.3 2.15 — — — — 25.1 12 95 543 8.2 29 530 555  Std. dev. 0 2.95 0.54 — — — — 7.28 2.28 9.19 98.7 0.28 9.61 188 179 

N obs. 12 11 2 0 0 0 0 12 12 12 12 12 12 12 10 

PE01.8M Mean 0.2 2.49 — — — — — 12 8.21 74 298 7.6 56 46 41.8  Median 0.2 2.2 — — — — — 9.2 8.4 74 329 7.7 56 38 34.6  Minimum 0.2 1.4 — — — — — 6 4.4 48 152 7.2 56 17 11.9  Maximum 0.2 4.6 — — — — — 19.9 11.2 90 395 7.9 56 77 113  Std. dev. 0 1.14 — — — — — 5.8 2.39 15.4 85.2 0.27 — 21.9 37.2 

N obs. 7 7 0 0 0 0 0 7 7 7 7 6 1 7 6 

PI00.2M Mean 0.2 4.52 0.05 — — — — 15.7 7.4 72 514 8 51.5 29 27.9  Median 0.2 4.9 0 — — — — 17.1 6.8 74 496 8 42 27 34.6  Minimum 0.2 2.4 0 — — — — 5.9 3.9 44 293 7.6 17 7 6.1  Maximum 0.2 6.4 0.14 — — — — 27 11.7 96 804 8.7 125 78 55.9  Std. dev. 0 1.44 0.08 — — — — 7.34 2.21 12.4 133 0.27 33.1 19.6 17.1 

N obs. 12 11 3 0 0 0 0 12 12 12 12 11 11 12 9 

WD00.2M Mean 0.2 4.79 0.02 — — — — 15.1 8.07 78 554 8 48.8 50 32.3  Median 0.2 4.92 0.02 — — — — 16.3 8 81 522 8 42 26 33.2  Minimum 0.2 1.3 0 — — — — 2.1 2.6 26 248 7.3 9 6 13.5  Maximum 0.2 8.5 0.04 — — — — 26 12.6 113 909 8.4 160 290 61  Std. dev. 0 2.59 0.03 — — — — 7.54 2.91 22 204 0.29 39.5 77.9 14.1 

N obs. 12 12 2 0 0 0 0 12 12 12 12 12 12 12 10 
E-7

Table E-1. Continued.

Samplinglocation Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Total

suspend

solids

(mg/L)

1993 Near-bottom measurements: 

M202.2N Mean 2.36 2.57 0 — — — — 8.27 12.4 102 458 8.4 — 33 —  Median 1.9 2.1 0 — — — — 6 12.7 98 492 8.1 — 27 —  Minimum 1.1 1.3 0 — — — — 2.8 7.6 77 381 8 — 21 —  Maximum 5.6 5.8 0 — — — — 17.2 17.3 128 500 9.1 — 50 —  Std. dev. 1.54 1.53 0 — — — — 5.64 4.04 22.2 66.5 0.62 — 15.3 — 

N obs. 7 7 2 — — — — 7 7 7 3 3 — 3 0 

M235.5D Mean 2.01 2.22 0 — — — — 8.23 9.91 84 284 — — 53 —  Median 1.9 2.17 0 — — — — 8 10.4 83 298 — — 53 —  Minimum 0.8 1 0 — — — — 3.8 7.6 60 225 — — 53 —  Maximum 3.4 3.6 0 — — — — 17.1 12 106 330 — — 53 —  Std. dev. 1.08 1.08 0 — — — — 4.41 1.72 14.5 53.8 — — — — 

N obs. 7 7 2 — — — — 7 7 7 3 0 — 1 0 

M237.2G Mean 2.3 2.5 0.4 — — — — 7.39 11.9 97 348 7.7 — 1035 —  Median 1.95 2.15 0.4 — — — — 6.25 12.6 96 307 7.7 — 1035 —  Minimum 1.3 1.5 0.09 — — — — 1.4 7.9 81 207 7.6 — 24 —  Maximum 4.6 4.8 0.71 — — — — 17.6 14.8 119 529 7.9 — 2045 —  Std. dev. 1.09 1.09 0.44 — — — — 5.78 2.51 12.4 165 0.25 — 1429 — 

N obs. 8 8 2 — — — — 8 8 8 3 2 — 2 0 

M241.4K Mean 4.98 5.21 0.13 — — — — 2.73 13.8 101 472 8 — 56 —  Median 5.55 5.79 0.03 — — — — 1.8 13.7 99 545 7.9 — 55 —  Minimum 1.3 1.5 0.01 — — — — 0.6 11.3 96 317 7.7 — 19 —  Maximum 7.6 7.8 0.34 — — — — 8.1 15.7 109 599 8.3 — 95 —  Std. dev. 2.54 2.53 0.19 — — — — 2.82 1.49 6.14 131 0.3 — 31.4 — 

N obs. 6 6 3 — — — — 6 6 6 5 3 — 4 0 

PI00.2M Mean 3.82 4.02 — — — — — 11.6 7.42 65 657 7.9 — 53 64.5  Median 3.05 3.25 — — — — — 11 8 71 657 7.9 — 53 64.5  Minimum 2.2 2.4 — — — — — 5.7 2.2 24 657 7.9 — 53 64.5  Maximum 6.2 6.4 — — — — — 19 11.2 92 657 7.9 — 53 64.5  Std. dev. 1.76 1.76 — — — — — 5.51 3.23 23.5 — — — — — 

N obs. 6 6 0 — — — — 6 6 6 1 1 — 1 1 
E-8

Table E-1. Continued.

Samplinglocation Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Total

suspend

solids

(mg/L)

1994 Near-surface measurements: 

CA00.4M Mean 0.2 2.3 — 5 4 0 0 15.9 9.93 97 565 8.1 30.4 64 77.5  Median 0.2 2 — 5 4 0 0 15.3 9.55 93 617 8.1 25 38 46.8  Minimum 0.2 0.9 — 5 4 0 0 1 4.8 63 233 7.7 6 9 7.1  Maximum 0.2 6 — 5 4 0 0 29 14.8 177 750 8.6 80 410 608  Std. dev. 0 1.33 — — — — — 9.67 3 25.5 135 0.26 20.4 88.3 128 

N obs. 20 20 0 1 1 1 1 20 20 20 20 18 19 20 20 

CU11.6M Mean 0.2 — — — — — — 17.3 9.56 97 367 8.1 — 107 115  Median 0.2 — — — — — — 17.9 10.1 92 403 8.3 — 22 22.1  Minimum 0.2 — — — — — — 1.3 3.6 41 186 7.3 — 11 17.7  Maximum 0.2 — — — — — — 30 16.8 146 472 8.6 — 980 1488  Std. dev. 0 — — — — — — 9.47 3.13 27.5 96.9 0.4 — 236 354 

N obs. 17 0 0 0 0 0 0 17 17 17 16 8 0 17 17 

DC01.0M Mean 0.2 1.88 — — — — — 16.1 8.21 78 482 7.9 — 96 80  Median 0.2 1.9 — — — — — 16.2 6.9 80 462 7.8 — 39 39  Minimum 0.2 1.2 — — — — — 2 1.8 21 230 7.4 — 12 11.9  Maximum 0.2 3.3 — — — — — 29 18.1 131 807 8.6 — 510 644  Std. dev. 0 0.42 — — — — — 9.19 4 28.1 170 0.31 — 133 138 

N obs. 20 19 0 0 0 0 0 20 20 20 19 12 0 20 20 

I005.7M Mean 0.2 0.65 0 20 3 0 0 14 10.6 101 620 8.2 22.4 72 52.2  Median 0.2 0.45 0 20 3 0 0 12.7 10.9 93 646 8 21.5 56 52.4  Minimum 0.2 0.35 0 20 3 0 0 3.1 6.2 75 448 7.8 14 11 14.9  Maximum 0.2 2 0 20 3 0 0 26 16.2 185 714 9.1 37 240 90.1  Std. dev. 0 0.52 0 — — — — 8.91 3.23 33.4 90 0.44 7.23 67.2 24.9 

N obs. 9 9 9 1 1 1 1 9 9 9 9 8 8 9 9 

I007.0W Mean 0.2 1.21 0.17 — — — — 17.5 7.47 73 627 8 27.1 67 68.1  Median 0.2 1.1 0.12 — — — — 20.5 7.3 77 645 8 29 40 46.6  Minimum 0.2 0.6 0 — — — — 2.5 3 39 385 7.5 14 22 21  Maximum 0.2 2.1 0.58 — — — — 31.2 13.6 105 753 8.2 44 460 352  Std. dev. 0 0.45 0.17 — — — — 9.28 3.22 17.6 97.5 0.17 7.24 97.1 74.4 

N obs. 19 19 14 0 0 0 0 19 19 19 19 16 19 19 19 

M193.2F Mean 0.2 7.5 — 3 7 0 0 16 9.56 93 543 8.2 22.1 120 190  Median 0.2 6.8 — 3 7 0 0 17.2 9.65 93 562 8.2 21 64 95.4  Minimum 0.2 4.6 — 3 7 0 0 0.6 5.6 73 256 7.9 5 20 17.3  Maximum 0.2 11.7 — 3 7 0 0 28.5 15.3 119 690 8.7 48 470 1145  Std. dev. 0 1.98 — — — — — 9.7 2.44 11.5 126 0.24 11.7 132 262 

N obs. 20 20 0 1 1 1 1 20 20 20 20 17 20 19 20 
E-9

Table E-1. Continued.

Samplinglocation Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Total

suspend

solids

(mg/L)

1994 Near-surface measurements: 

M196.9Q Mean 0.2 4.51 0.54 42.5 7 0 0 15.3 10.8 104 414 8.3 31.8 61 92.9  Median 0.2 4.3 0.54 42.5 7 0 0 16.3 10.5 99 443 8.3 30.5 33 49.1  Minimum 0.2 2.4 0.54 5 7 0 0 0.1 6.2 80 198 8 8 17 23.2  Maximum 0.2 8.2 0.54 80 7 0 0 28 17.5 176 505 8.9 60 430 827  Std. dev. 0 1.44 — 53 0 0 0 10.3 2.89 22.6 87.6 0.24 12.5 89.7 175 

N obs. 20 20 1 2 2 2 2 20 20 20 20 18 20 20 20 

M201.7Q Mean 0.2 4.19 0 100 23 100 5 16.1 11.5 115 387 8.5 36.8 41 41.2  Median 0.2 4.4 0 100 23 100 5 15.9 10.6 102 415 8.4 34 30 31.6  Minimum 0.2 1.9 0 100 23 100 5 0.9 6.2 74 143 7.9 8 8 9.2  Maximum 0.2 5.5 0 100 23 100 5 31 17.2 217 472 9.2 80 250 240  Std. dev. 0 0.87 0 — — — — 10.2 3.27 34.1 84.4 0.36 16.5 51.1 49.3 

N obs. 20 20 17 1 1 1 1 20 20 20 19 16 19 20 20 

M202.2N Mean 0.2 1.97 0 100 16 99 20 16.4 11.2 113 395 8.5 37.7 42 43.7  Median 0.2 2.1 0 100 16 99 20 16.5 10.7 101 410 8.5 35 30 35  Minimum 0.2 0.4 0 100 16 99 20 1 5 57 143 8 9 9 9  Maximum 0.2 2.6 0 100 16 99 20 31.1 17.1 204 474 9.1 68 240 222  Std. dev. 0 0.58 0 — — — — 10.1 3.54 40.6 74 0.33 16.2 49.2 46.2 

N obs. 20 20 18 1 1 1 1 20 20 20 19 17 20 20 20 

M203.5R Mean 0.2 0.9 0.02 80 12 50 2 17.1 11 113 412 8.5 29.6 51 64  Median 0.2 0.65 0 80 12 50 2 17.9 10.4 104 429 8.4 30 35 41.7  Minimum 0.2 0.41 0 60 3 0 0 0 6.7 78 201 8 9 9 9.3  Maximum 0.2 5 0.07 100 20 100 3 32.6 15.6 183 632 9.3 56 250 245  Std. dev. 0 1.1 0.03 28.3 12 70.7 2.1 10.2 2.75 29.3 88.2 0.37 11.6 56.1 60.5 

N obs. 16 16 15 2 2 2 2 16 16 16 16 14 15 16 16 

M206.0S Mean 0.2 1.14 0 95 12 50 3 18.5 11.8 124 389 8.7 27.1 59 59.8  Median 0.2 1.05 0 95 12 50 3 19.5 11.4 120 405 8.7 25.5 38 43.2  Minimum 0.2 0.67 0 90 4 0 0 1.5 6 70 140 8.2 10 16 8.8  Maximum 0.2 2.5 0 100 19 100 5 33.5 20.7 179 464 9.5 61 310 237  Std. dev. 0 0.4 0 7.07 10.6 70.7 3.5 10.3 3.74 34.4 73.5 0.31 12.1 68.6 53.5 

N obs. 17 17 16 2 2 2 2 17 17 17 16 15 16 17 17 

M206.1T Mean 0.2 0.75 0 100 21 100 5 21.8 7.3 84 425 8.1 16.6 84 84.7  Median 0.2 0.68 0 100 21 100 5 23.1 8 76 445 8.2 16 67 72  Minimum 0.2 0.45 0 100 21 100 5 0.9 3.8 48 141 7.4 10 16 13.4  Maximum 0.2 2 0 100 21 100 5 34.2 9.2 132 519 8.5 24 250 202  Std. dev. 0 0.43 0 — — — — 9.47 1.68 25.3 109 0.35 4.9 61.6 48.6 

N obs. 11 11 8 1 1 1 1 11 11 11 10 8 10 11 11 
E-10

Table E-1. Continued.

Samplinglocation Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Total

suspend

solids

(mg/L)

1994 Near-surface measurements: 

M235.5D Mean 0.2 0.9 0.01 — — — — 18.6 9.23 93 313 8.1 25.2 72 64.5  Median 0.2 0.67 0 — — — — 19 9.5 92 314 8.1 20.5 52 57.8  Minimum 0.2 0.32 0 — — — — 5.5 2.4 32 204 7.3 10 13 15.4  Maximum 0.2 2.3 0.09 — — — — 31 20 196 400 9 55 175 159  Std. dev. 0 0.56 0.02 — — — — 8.96 5.15 45.7 47.4 0.45 13.8 48.3 40.2 

N obs. 17 17 16 0 0 0 0 17 17 17 17 13 16 15 17 

M237.2G Mean 0.2 2.09 0.18 90 4 0 0 16.5 10.5 104 408 8.4 30.6 57 67.1  Median 0.2 2 0.11 90 4 0 0 15.6 10.1 97 434 8.3 27 36 46.7  Minimum 0.2 0.84 0 90 4 0 0 1.9 6.8 83 131 7.9 10 15 18.6  Maximum 0.2 4.4 0.68 90 4 0 0 29.5 16.2 173 494 9.5 65 360 298  Std. dev. 0 0.93 0.2 — — — — 10.1 2.97 21.2 90.8 0.39 12.8 75.5 63.1 

N obs. 19 19 19 1 1 1 1 19 19 19 19 16 19 19 19 

M241.4K Mean 0.2 9.55 — — — — — 15.9 10.9 106 413 8.3 29.9 46 71.9  Median 0.2 9.6 — — — — — 15.7 10.4 99 431 8.2 30 34 50.2  Minimum 0.2 6.3 — — — — — 1.5 6.6 80 206 8 15 16 18.1  Maximum 0.2 12.2 — — — — — 29.3 17.2 160 492 9.2 60 150 344  Std. dev. 0 1.77 — — — — — 9.72 2.99 20 76.6 0.32 11.8 31.7 72.2 

N obs. 19 19 0 0 0 0 0 19 19 19 19 16 19 19 19 

MO02.0X Mean 0.2 5.76 — — — — — 16.1 9.69 96 546 8.2 21.7 113 179  Median 0.2 6.1 — — — — — 17.1 9.7 95 561 8.2 19 64 84.7  Minimum 0.2 4 — — — — — 0.6 6.3 82 248 7.9 3 22 15.7  Maximum 0.2 7.9 — — — — — 28.5 14.4 127 709 8.7 55 410 1231  Std. dev. 0 1.09 — — — — — 9.58 2.1 11.1 147 0.23 13.5 125 267 

N obs. 20 19 0 0 0 0 0 20 20 20 20 18 20 19 20 

PE01.8M Mean 0.2 1.58 — 10 2 0 0 15.6 7.41 69 399 7.8 — 55 39.8  Median 0.2 1.6 — 10 2 0 0 15.2 5.9 62 405 7.8 — 32 37.9  Minimum 0.2 0.9 — 10 2 0 0 2 2.8 31 239 7.4 — 12 9.9  Maximum 0.2 2.6 — 10 2 0 0 28.1 18.2 132 544 8.2 — 234 124  Std. dev. 0 0.43 — — — — — 9.09 3.99 24.8 86.2 0.25 — 57 25.9 

N obs. 19 19 0 1 1 1 1 19 19 19 18 11 0 19 19 

PI00.2M Mean 0.2 3.14 — 100 15 100 5 16.2 9.25 92 528 8 42.5 76 123  Median 0.2 3.2 — 100 15 100 5 15.7 9.25 85 517 7.9 42.5 24 25.3  Minimum 0.2 2 — 100 15 100 5 0.3 4.1 49 149 7.6 3 7 6.6  Maximum 0.2 4.4 — 100 15 100 5 31.2 16.3 145 825 8.4 88 1000 1989  Std. dev. 0 0.55 — — — — — 9.79 2.88 27.6 135 0.26 20.9 218 439 

N obs. 20 20 0 1 1 1 1 20 20 20 20 17 20 20 20 
E-11

Table E-1. Continued.

Samplinglocation Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Total

suspend

solids

(mg/L)

1994 Near-surface measurements: 

WD00.2M Mean 0.2 4.47 — — — — — 11.4 10.5 94 648 8 58.5 43 39.6  Median 0.2 4.05 — — — — — 10.7 9.65 91 649 7.9 51 15 16.3  Minimum 0.2 1 — — — — — 2.9 7.8 84 379 7.6 14 8 7  Maximum 0.2 8.2 — — — — — 24.9 14.2 118 873 8.6 112 180 151  Std. dev. 0 2.97 — — — — — 7.39 2.36 12.1 215 0.43 36.5 67.7 55.5 

N obs. 6 6 0 0 0 0 0 6 6 6 6 4 6 6 6 

1994 Near-bottom measurements: 

M201.7Q Mean 3.98 4.18 — — — — — 11.5 10.8 93 — — — — 98.3  Median 4.35 4.55 — — — — — 10.2 10.3 95 — — — — 98.3  Minimum 1.7 1.9 — — — — — 0.9 1.3 17 — — — — 98.3  Maximum 5.3 5.5 — — — — — 27.3 16.9 137 — — — — 98.3  Std. dev. 1.02 1.02 — — — — — 8.57 4.22 27.8 — — — — — 

N obs. 14 14 0 — — — — 14 14 14 0 0 — 0 1 

M202.2N Mean 1.92 2.12 0 — — — — 14.2 9.75 90 142 — — — 185  Median 1.9 2.1 0 — — — — 13.3 9.5 91 142 — — — 185  Minimum 1.1 1.3 0 — — — — 2 3.2 42 142 — — — 185  Maximum 2.4 2.6 0 — — — — 28.2 17 130 142 — — — 185  Std. dev. 0.37 0.37 — — — — — 9.04 3.61 23.3 — — — — — 

N obs. 13 13 1 — — — — 13 13 13 1 0 — 0 1 

M237.2G Mean 1.73 1.94 — — — — — 13.2 12.1 115 — — — — —  Median 1.5 1.7 — — — — — 14.2 12.6 98 — — — — —  Minimum 1 1.2 — — — — — 1.9 9.7 93 — — — — —  Maximum 2.5 2.7 — — — — — 26.5 16 170 — — — — —  Std. dev. 0.68 0.67 — — — — — 9.46 2.35 28.8 — — — — — 

N obs. 7 7 0 — — — — 7 7 7 0 0 — 0 0 

1995 Near-surface measurements: 

CA00.4M Mean 0.2 3.51 1.3 85 4 25 1 15 10.2 99 577 7.8 29.9 143 175  Median 0.2 2.7 1.3 85 4 25 1 14.7 9.9 94 600 7.7 28.5 35 34.8  Minimum 0.2 1.1 1.3 70 1 0 0 0 5.2 58 232 7.3 3 19 13.8  Maximum 0.2 9.5 1.3 100 7 50 1 30.8 14.5 167 761 8.3 57 1900 2316  Std. dev. 0 2.37 — 21.2 4.24 35.4 .71 10.2 2.69 25 138 0.29 13.6 392 486 

N obs. 24 23 1 2 2 2 2 24 24 24 24 24 24 24 24 
E-12

Table E-1. Continued.

Samplinglocation Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Total

suspend

solids

(mg/L)

1995 Near-surface measurements: 

CU11.6M Mean 0.2 7.15 0 60 6 0 0 16.7 10.2 104 351 7.7 19.5 138 179  Median 0.2 7.15 0 60 6 0 0 15.9 7.9 85 369 7.7 19.5 22 23.3  Minimum 0.2 5.8 0 60 6 0 0 0.9 5.4 68 155 7 7 11 9.6  Maximum 0.2 8.5 0 60 6 0 0 31.5 25 347 547 8.5 32 1550 2337  Std. dev. 0 1.91 — — — — — 9.92 4.89 61.7 122 0.47 17.7 356 534 

N obs. 19 2 1 1 1 1 1 19 19 19 19 16 2 19 19 

DC01.0M Mean 0.2 2.42 — 90 1 0 0 15.1 7.78 73 521 7.6 — 133 136  Median 0.2 2.1 — 90 1 0 0 16.1 7.3 77 517 7.5 — 37 42.1  Minimum 0.2 1.3 — 90 1 0 0 1.2 2.8 33 136 6.7 — 9 6.6  Maximum 0.2 4.67 — 90 1 0 0 32.5 18.1 131 1098 10.3 — 1550 1745  Std. dev. 0 0.98 — — — — — 9.65 3.89 27.5 231 0.71 — 326 352 

N obs. 24 22 0 1 1 1 1 24 24 24 24 22 0 24 24 

I005.7M Mean 0.2 1.07 0.04 — — — — 14.3 10.9 102 635 8.1 22.1 72 73.7  Median 0.2 0.46 0 — — — — 14.7 12.4 105 627 8.1 24 43 57.3  Minimum 0.2 0.34 0 — — — — 4 5.4 69 490 7.6 10 24 21.1  Maximum 0.2 4.3 0.3 — — — — 31 14.8 146 803 8.7 35 270 245  Std. dev. 0 1.18 0.09 — — — — 8.58 3.38 23.6 92.8 0.34 8.04 66.5 60 

N obs. 13 13 13 0 0 0 0 13 13 13 13 13 13 13 13 

I007.0W Mean 0.2 1.49 0.15 55 3 3 1 14.9 10 93 684 7.9 26 65 75.7  Median 0.2 0.98 0.12 55 3 3 1 13.3 10.5 97 701 7.9 25.5 52 51  Minimum 0.2 0.5 0 40 2 0 0 0 5 65 477 7.4 11 21 26.2  Maximum 0.2 5.5 0.55 70 4 5 2 33.1 16.4 116 862 8.8 62 260 370  Std. dev. 0 1.38 0.16 21.2 1.41 3.54 1.4 10.6 3.43 14.1 93 0.29 10.8 49.8 70.7 

N obs. 24 24 19 2 2 2 2 24 24 24 24 23 24 24 24 

M193.2F Mean 0.2 7.7 1.15 5 3 0 0 13.5 10.2 92 582 7.9 21.1 130 212  Median 0.2 7 1.15 5 3 0 0 12 10.5 97 556 8 21 66 103  Minimum 0.2 4.8 1.15 5 3 0 0 1 5.5 67 404 7.4 4 22 28.7  Maximum 0.2 13.7 1.15 5 3 0 0 29.4 15.2 112 809 8.2 43 580 981  Std. dev. 0 2.29 — — — — — 10.2 3.2 11.3 119 0.25 11.8 135 227 

N obs. 25 25 1 1 1 1 1 25 25 25 25 25 25 25 25 

M196.9Q Mean 0.2 4.32 — 5 5 0 0 13.1 10.7 96 459 7.9 31.8 56 75.1  Median 0.2 4 — 5 5 0 0 11.3 10.5 97 458 7.9 29 43 53.9  Minimum 0.2 0.95 — 5 4 0 0 0.1 5.8 71 358 7.4 13 10 13.4  Maximum 0.2 10.5 — 5 5 0 0 29.8 16.2 117 568 8.6 70 190 275  Std. dev. 0 2.26 — 0 0.71 0 0 10.8 3.4 12.3 54.8 0.28 15.4 46.8 65 

N obs. 25 25 0 2 2 2 2 25 25 25 25 25 25 25 25 
E-13

Table E-1. Continued.

Samplinglocation Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Total

suspend

solids

(mg/L)

1995 Near-surface measurements: 

M201.7Q Mean 0.2 4.76 0.01 90 4 0 0 15.6 10.5 100 438 8.2 38.7 31 31.2  Median 0.2 4.6 0 90 4 0 0 15.9 10.4 100 431 8.2 35 31 27.8  Minimum 0.2 3.4 0 90 4 0 0 0.5 4.7 58 370 7.6 19 10 8.1  Maximum 0.2 7.6 0.2 90 4 0 0 29.2 17.2 123 511 8.8 83 67 60.6  Std. dev. 0 1.02 0.04 — — — — 9.71 3.56 17.4 39.5 0.32 16.5 14.1 14.1 

N obs. 22 22 21 1 1 1 1 22 22 22 22 21 22 22 22 

M202.2N Mean 0.2 2.27 0 — — — — 16.7 10.4 103 432 8.2 36.3 31 34.5  Median 0.2 2.1 0 — — — — 16.8 10.7 98 417 8.1 31 32 37.3  Minimum 0.2 1.2 0 — — — — 1.9 5.8 70 383 7.7 19 10 8.6  Maximum 0.2 6.1 0.09 — — — — 30.3 15.6 199 492 8.8 82 54 54.7  Std. dev. 0 1.21 0.02 — — — — 9.26 3.33 27.4 34.5 0.3 17.1 14.7 14.9 

N obs. 21 21 19 0 0 0 0 21 21 21 21 20 21 21 21 

M202.6T Mean 0.2 11.5 0.4 — — — — 17.9 9.23 92 434 7.9 41.7 42 54.4  Median 0.2 11 0.4 — — — — 20.6 7.8 95 406 7.9 41.5 27 35  Minimum 0.2 8.9 0.4 — — — — 0.5 5.9 72 354 7.5 15 11 11.5  Maximum 0.2 16.2 0.4 — — — — 29.4 16 111 539 8.3 60 120 153  Std. dev. 0 2.59 — — — — — 10.4 3.21 11.7 61.3 0.23 13.9 34.5 43.8 

N obs. 16 13 1 0 0 0 0 16 16 16 16 15 14 16 16 

M203.5R Mean 0.2 0.95 0.12 — — — — 15.3 11 104 439 8.1 30.6 51 58.2  Median 0.2 0.65 0.05 — — — — 15.6 10.4 101 416 8.1 28.5 38 47.8  Minimum 0.2 0.38 0 — — — — 2.1 6.6 73 355 7.5 17 10 1.1  Maximum 0.2 3.7 0.6 — — — — 30 18 131 531 8.5 57 251 170  Std. dev. 0 0.92 0.2 — — — — 10.1 3.72 17.4 56.3 0.27 11.3 55.8 45.5 

N obs. 17 17 15 0 0 0 0 17 17 17 17 16 16 17 17 

M206.0S Mean 0.2 1.1 0.01 97 6 51 2 15.7 13.5 133 413 8.4 33 42 48.4  Median 0.2 1.02 0 96.5 6 65 2 14.7 12.5 129 408 8.4 23 43 46.7  Minimum 0.2 0.35 0 95 3 0 0 1.1 6 72 362 7.5 16 8 10.7  Maximum 0.2 3.3 0.14 100 9 75 3 32.6 25 355 469 9.1 75 81 125  Std. dev. 0 0.68 0.04 2.45 2.75 34.7 1.3 10.5 5.22 55.5 27.1 0.42 19.1 21 27 

N obs. 24 24 23 4 4 4 4 24 24 24 24 22 23 24 24 

M206.1T Mean 0.2 1 0.01 100 6 8 1 13.8 9.81 92 452 7.9 27.6 42 45.7  Median 0.2 0.7 0 100 6 8 1 14 9.6 89 441 7.9 22 45 46.2  Minimum 0.2 0.5 0 100 5 0 0 3.8 5.3 59 356 7.1 17 10 11.5  Maximum 0.2 2.7 0.06 100 6 15 1 28.3 15.1 125 610 8.2 48 64 81.6  Std. dev. 0 0.8 0.02 0 0.71 10.6 .71 7.71 2.73 19.6 69.1 0.32 10.5 19.3 24.7 

N obs. 12 12 11 2 2 2 2 12 12 12 12 11 11 12 12 
E-14

Table E-1. Continued.

Samplinglocation Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Total

suspend

solids

(mg/L)

1995 Near-surface measurements: 

M235.5D Mean 0.2 1.23 0.01 91.7 4 9 0 15.6 10 91 375 7.9 23.7 76 75.4  Median 0.2 0.66 0 100 4 0 0 15.2 9.3 90 390 7.9 22 60 50.1  Minimum 0.2 0.33 0 70 1 0 0 2.1 1.9 25 155 7.3 5 16 13.6  Maximum 0.2 5.5 0.21 100 7 40 1 29.6 25 181 499 9.1 53 340 259  Std. dev. 0 1.26 0.04 13.3 2.42 16.3 .52 9.85 6.28 42.9 76.9 0.49 12.7 73.2 71.8 

N obs. 24 24 22 6 6 6 6 24 24 24 24 23 21 24 24 

M237.2G Mean 0.2 2.22 0.37 67.5 2 0 0 16.3 10 97 424 7.9 28 71 91.9  Median 0.2 1.8 0.35 67.5 2 0 0 16.7 9.85 100 433 7.9 24.5 52 90.2  Minimum 0.2 0.81 0 60 1 0 0 2.2 5.2 68 212 7.3 8 11 -0.1  Maximum 0.2 6.1 1.09 75 2 0 0 30.1 17 128 507 8.4 64 270 187  Std. dev. 0 1.41 0.33 10.6 0.71 0 0 9.71 3.11 15.5 71.6 0.3 14.1 63.4 57 

N obs. 20 20 17 2 2 2 2 20 20 20 20 20 20 20 20 

M241.4K Mean 0.2 11.2 — — — — — 12.8 11.6 103 464 8.1 39.5 46 72  Median 0.2 11 — — — — — 10.8 10.6 101 463 8 30 45 64.1  Minimum 0.2 8 — — — — — 0.1 6.3 57 364 7.7 17 6 -0.1  Maximum 0.2 17.7 — — — — — 29.5 20 137 586 8.6 80 96 195  Std. dev. 0 2.35 — — — — — 10.9 4.07 16.3 54.8 0.28 23.4 29.7 58 

N obs. 23 23 0 0 0 0 0 23 23 23 23 22 23 23 23 

MO02.0X Mean 0.2 6.9 — — — — — 13.9 9.72 89 626 7.8 20 156 264  Median 0.2 6.1 — — — — — 12.6 9.4 94 631 7.9 16 78 113  Minimum 0.2 4.5 — — — — — 1.4 5.5 67 402 7.3 4 22 31.7  Maximum 0.2 11 — — — — — 29.5 13.7 100 824 8.1 46 590 1107  Std. dev. 0 1.88 — — — — — 9.83 2.82 9.73 140 0.23 12.8 155 284 

N obs. 25 25 0 0 0 0 0 25 25 25 25 25 25 25 25 

PE01.8M Mean 0.2 2.22 — 54.5 4 3 1 14.5 7.94 74 429 7.6 41 103 116  Median 0.2 1.9 — 56.5 4 0 0 14.7 7.5 75 402 7.6 41 43 41.3  Minimum 0.2 1.2 — 5 1 0 0 0.1 3.2 38 169 7 28 6 3.4  Maximum 0.2 5.3 — 100 6 10 3 30.2 17.4 119 652 10.2 54 1400 1751  Std. dev. 0 0.98 — 51.6 2.38 5 1.5 9.74 3.31 20.5 134 0.64 18.4 284 350 

N obs. 24 24 0 4 4 4 4 24 24 24 24 22 2 23 24 

PI00.2M Mean 0.2 3.39 — 97.5 6 30 1 16 9.31 89 565 7.8 42.5 55 77  Median 0.2 3.4 — 97.5 6 30 1 15.9 8.7 89 564 7.8 36 27 27.7  Minimum 0.2 1.4 — 95 4 0 0 0.2 2.6 34 251 7.3 3 10 7.3  Maximum 0.2 5.2 — 100 8 60 1 30 16.6 129 748 8.4 115 600 1141  Std. dev. 0 0.89 — 3.54 2.83 42.4 .71 9.73 3.76 24.4 120 0.25 26.1 124 238 

N obs. 22 20 0 2 2 2 2 22 22 22 22 22 20 22 22 
E-15

Table E-1. Continued.

Samplinglocation Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Total

suspend

solids

(mg/L)

1995 Near-surface measurements: 

WD00.2M Mean 0.2 3.15 — — — — — 17.8 7.63 78 745 7.6 50.1 43 46.7  Median 0.2 2.4 — — — — — 17.2 7 74 785 7.6 37.5 29 26.4  Minimum 0.2 1.05 — — — — — 1.5 4.5 50 399 7.1 6 6 7.5  Maximum 0.2 7.5 — — — — — 31 13.8 114 968 8 130 260 336  Std. dev. 0 1.75 — — — — — 8.67 2.47 16 199 0.25 35.4 58.8 76.4 

N obs. 18 18 0 0 0 0 0 18 18 18 18 18 18 18 18 

1995 Near-bottom measurements: 

I007.0W Mean 2.21 2.43 — — — — — 13.3 9.64 90 706 8 — — —  Median 1.4 1.63 — — — — — 13.2 10.3 96 735 8.1 — — —  Minimum 0.9 1.16 — — — — — 1.9 5.9 64 477 7.7 — — —  Maximum 5.3 5.5 — — — — — 22.1 13.2 104 815 8.2 — — —  Std. dev. 1.61 1.6 — — — — — 6.09 2.5 15.2 110 0.18 — — — 

N obs. 8 8 0 — — — — 8 8 8 7 6 — 0 0 

M201.7Q Mean 4.56 4.76 — — — — — 15.1 9.5 88 444 8 — — —  Median 4.4 4.6 — — — — — 14.4 8.8 84 429 7.9 — — —  Minimum 3.2 3.4 — — — — — 0.6 3.8 49 380 7.4 — — —  Maximum 7.4 7.6 — — — — — 28.5 17.1 120 510 8.8 — — —  Std. dev. 1.02 1.02 — — — — — 9.49 4.01 21 40.6 0.35 — — — 

N obs. 22 22 0 — — — — 22 22 22 21 21 — 0 0 

M202.2N Mean 2.07 2.27 — — — — — 16.6 10 99 432 8.1 — — —  Median 1.9 2.1 — — — — — 16.2 10.4 95 420 8 — — —  Minimum 1 1.2 — — — — — 1.9 5.5 63 383 7.7 — — —  Maximum 5.9 6.1 — — — — — 30.2 15.4 181 494 8.8 — — —  Std. dev. 1.21 1.21 — — — — — 9.23 3.32 25.5 33.3 0.3 — — — 

N obs. 21 21 0 — — — — 21 21 21 21 20 — 0 0 

M206.0S Mean 1.25 1.48 — — — — — 17.7 10.7 104 413 8.2 — 44 —  Median 0.9 1.15 — — — — — 21.5 9 100 413 8.1 — 44 —  Minimum 0.8 1.03 — — — — — 1.6 5.4 63 362 7.6 — 44 —  Maximum 3.1 3.3 — — — — — 30.4 22.4 160 469 9.1 — 44 —  Std. dev. 0.84 0.83 — — — — — 9.63 5.41 31.5 27.9 0.4 — — — 

N obs. 11 11 0 — — — — 11 11 11 11 11 — 1 0 
E-16

Table E-1. Continued.

Samplinglocation Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Total

suspend

solids

(mg/L)

1995 Near-bottom measurements: 

M235.5D Mean 2.36 2.57 — — — — — 21.5 4.05 43 399 7.4 — 50 19.1  Median 2.15 2.35 — — — — — 22.7 3.35 42 438 7.4 — 50 19.1  Minimum 0.9 1.16 — — — — — 9.8 1 13 160 7.1 — 50 19.1  Maximum 5.3 5.5 — — — — — 29.5 8.1 74 500 7.6 — 50 19.1  Std. dev. 1.44 1.43 — — — — — 7.76 2.45 20.5 106 0.16 — — — 

N obs. 8 8 0 — — — — 8 8 8 8 7 — 1 1 

M237.2G Mean 1.75 1.95 — — — — — 19.6 9.09 95 434 7.9 — — —  Median 1.6 1.8 — — — — — 25.6 7.8 98 464 7.9 — — —  Minimum 1.2 1.4 — — — — — 3.4 5.2 68 315 7.3 — — —  Maximum 2.8 3 — — — — — 30 13.3 118 507 8.4 — — —  Std. dev. 0.54 0.54 — — — — — 10 2.87 13.6 61.4 0.3 — — — 

N obs. 11 11 0 — — — — 11 11 11 11 11 — 0 0 

1996 Near-surface measurements: 

CA00.4M Mean 0.2 2.56 0.85 72.5 2 0 0 13.7 11.2 106 560 7.7 30 122 118  Median 0.2 2.2 0.85 72.5 2 0 0 13 10.1 92 587 7.7 25 33 40.7  Minimum 0.2 0.3 0.85 50 2 0 0 0.2 6 65 172 7.1 4 10 7.6  Maximum 0.2 6.7 0.85 95 2 0 0 30.3 25 329 880 8.5 80 940 711  Std. dev. 0 1.75 — 31.8 0 0 0 10.4 4.6 52.8 179 0.38 20.5 228 203 

N obs. 22 22 1 2 2 2 2 22 22 22 22 22 21 22 22 

CU11.6M Mean 0.2 5.43 0 — — — — 16 10.2 101 332 7.7 35.3 152 170  Median 0.2 6.1 0 — — — — 15.5 11.2 97 339 7.6 35 51 51.8  Minimum 0.2 3.8 0 — — — — 2.6 5.8 73 142 7.2 24 9 11  Maximum 0.2 6.4 0 — — — — 30.6 17 186 468 8.4 47 790 778  Std. dev. 0 1.42 — — — — — 9.3 3.1 29.5 93.8 0.42 11.5 220 263 

N obs. 15 3 1 0 0 0 0 15 15 15 15 14 3 15 15 

DC01.0M Mean 0.2 2.02 — 66.7 8 10 0 14.5 7.17 64 690 7.3 77 71 79.3  Median 0.2 1.95 — 95 5 0 0 16.5 7.2 69 602 7.3 77 46 47.3  Minimum 0.2 0.7 — 5 2 0 0 0.4 1.6 20 232 7 75 5 10.1  Maximum 0.2 5.3 — 100 16 30 1 28.6 13.5 101 2262 7.7 79 320 394  Std. dev. 0 0.93 — 53.5 7.37 17.3 .58 9.71 4.01 25.7 454 0.2 2.83 74.7 96.6 

N obs. 23 21 0 3 3 3 3 23 23 23 23 21 2 23 23 
E-17

Table E-1. Continued.

Samplinglocation Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Total

suspend

solids

(mg/L)

1996 Near-surface measurements: 

I005.7M Mean 0.19 1.05 0.03 96 6 20 1 15.3 11.6 118 640 8.1 17.7 84 108  Median 0.2 0.49 0 96 6 20 1 13.5 10.9 97 560 8.1 17 74 76.7  Minimum 0 0.36 0 95 3 0 0 0.5 6.9 78 377 7.6 9 18 26.3  Maximum 0.2 3.4 0.19 97 8 40 1 33.2 25 359 918 8.9 34 200 267  Std. dev. 0.05 1.04 0.06 1.41 3.54 28.3 .71 10.5 4.5 69 179 0.4 6.82 53.3 76.1 

N obs. 15 15 15 2 2 2 2 15 15 15 15 13 15 15 15 

I007.0W Mean 0.2 1.56 0.15 80 5 0 0 15.5 9.25 89 687 7.9 22.9 77 79.3  Median 0.2 1.2 0.1 80 5 0 0 16 9.3 88 718 7.9 22 49 59.3  Minimum 0.2 0.52 0 80 5 0 0 0 4.5 54 373 7.3 8 23 27.2  Maximum 0.2 5.4 0.5 80 5 0 0 29.1 14.6 121 951 8.5 45 370 181  Std. dev. 0 1.25 0.15 — — — — 9.46 2.95 17.1 158 0.29 8.6 76.3 48.8 

N obs. 23 23 20 1 1 1 1 23 23 23 23 21 23 23 23 

M193.2F Mean 0.2 7.72 — 7.5 8 0 0 14 9.86 91 554 7.8 19.6 207 318  Median 0.2 7 — 7.5 8 0 0 13.5 9.2 92 568 7.8 15 80 131  Minimum 0.2 4.3 — 5 5 0 0 0.1 5.4 59 360 7.3 4 15 17.9  Maximum 0.2 18.3 — 10 10 0 0 28 15.2 117 740 8.2 65 1100 1795  Std. dev. 0 2.78 — 3.54 3.54 0 0 9.75 2.8 12.2 106 0.22 14 284 417 

N obs. 25 25 0 2 2 2 2 25 25 25 25 25 25 25 25 

M196.9Q Mean 0.2 3.89 0 16.7 7 0 0 13 10.7 97 445 7.9 34.1 66 93.5  Median 0.2 3.35 0 10 7 0 0 13.2 9.9 98 444 7.9 34 26 39  Minimum 0.2 1.14 0 5 5 0 0 0.2 6.8 70 264 7.3 8 5 7.4  Maximum 0.2 7.5 0 35 10 0 0 28.3 17.2 129 576 8.3 90 350 501  Std. dev. 0 1.89 — 16.1 2.52 0 0 10.3 2.95 12.9 74.5 0.24 19.4 87.8 120 

N obs. 26 26 1 3 3 3 3 26 26 26 26 26 25 26 26 

M201.7Q Mean 0.2 4.49 0.01 80 8 2 0 14.1 10.8 102 428 8 39.8 36 35.5  Median 0.2 4.6 0 90 3 0 0 13.1 11.2 99 433 8.1 38 22 27.6  Minimum 0.2 3 0 50 1 0 0 0.3 6.8 70 264 7.4 9 4 4.4  Maximum 0.2 6.4 0.14 100 20 5 1 28.6 14.8 150 564 8.5 110 220 188  Std. dev. 0 0.83 0.03 26.5 10.4 2.89 .58 10.3 2.5 18.6 63.4 0.25 22.6 44.1 36.8 

N obs. 25 25 22 3 3 3 3 25 25 25 25 25 24 25 25 

M202.2N Mean 0.2 2.3 0 95 12 0 0 14.8 10.6 101 427 8.1 41.5 37 35.8  Median 0.2 2.3 0 95 12 0 0 15 10.5 97 437 8.1 35 25 27.9  Minimum 0.2 0.8 0 90 1 0 0 1.1 6.4 70 263 7.3 9 5 5.2  Maximum 0.2 5.2 0 100 23 0 0 28.7 15.5 144 565 8.6 108 190 134  Std. dev. 0 0.85 0 7.07 15.6 0 0 9.81 2.76 16.9 62.1 0.27 26.5 40.1 29.4 

N obs. 24 24 23 2 2 2 2 24 24 24 24 24 24 24 24 
E-18

Table E-1. Continued.

Samplinglocation Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Total

suspend

solids

(mg/L)

1996 Near-surface measurements: 

M202.6T Mean 0.2 12.2 — 5 3 0 0 14 10.4 97 421 7.9 35.4 70 94.2  Median 0.2 11 — 5 3 0 0 14.5 10 98 428 8 35 31 36.5  Minimum 0.2 5.1 — 5 3 0 0 0.1 6.7 68 263 7.3 7 8 8.9  Maximum 0.2 19 — 5 3 0 0 27.6 15.1 127 519 8.4 86 370 534  Std. dev. 0 3.92 — 0 0 0 0 9.97 2.68 13.1 65.6 0.27 18.8 92 121 

N obs. 24 23 0 2 2 2 2 24 24 24 24 24 23 24 24 

M203.5R Mean 0.2 0.91 0.09 100 14 30 1 12.1 11.7 105 423 8 29.1 67 84.5  Median 0.2 0.7 0 100 14 30 1 9.7 12.2 105 421 8.1 29 32 45  Minimum 0.2 0.5 0 100 11 0 0 0.3 6.9 72 261 7.3 9 5 3.8  Maximum 0.2 3 0.6 100 16 60 1 29.1 16.5 132 543 8.5 55 350 505  Std. dev. 0 0.68 0.19 0 3.54 42.4 .71 10.3 2.66 17.3 68.8 0.32 13.4 96 121 

N obs. 20 20 19 2 2 2 2 20 20 20 20 19 17 20 20 

M206.0S Mean 0.2 1.16 0.01 93.3 7 17 1 14.9 13.7 131 389 8.5 32 60 61.5  Median 0.2 1.08 0 100 6 0 0 16.9 13.9 140 404 8.6 26 32 43.5  Minimum 0.2 0.55 0 80 1 0 0 1 5.2 55 264 7.1 9 7 5.8  Maximum 0.2 2.7 0.23 100 15 50 2 29.6 25 185 517 9.1 85 210 196  Std. dev. 0 0.49 0.05 11.5 7.09 28.9 1.2 9.98 4.67 36.4 61.9 0.56 20.6 62.9 56 

N obs. 23 23 23 3 3 3 3 23 23 23 23 22 23 23 23 

M206.1T Mean 0.2 1.01 0.01 90 10 30 1 16.2 8.49 83 470 7.7 32.9 50 49.5  Median 0.2 0.73 0 100 10 0 0 18.7 7.1 79 494 7.6 25 39 45.4  Minimum 0.2 0.55 0 70 4 0 0 3 3 32 262 7.2 9 9 10.7  Maximum 0.2 2.5 0.09 100 16 90 3 31.4 17.2 183 599 8.3 60 210 158  Std. dev. 0 0.68 0.02 17.3 6 52 1.7 8.58 4.62 43 98 0.33 17.6 54.3 37.1 

N obs. 17 17 17 3 3 3 3 17 17 17 17 17 17 17 17 

M235.5D Mean 0.2 1.6 0.04 100 1 0 0 18.6 7.71 79 379 7.6 21.7 129 137  Median 0.2 1.18 0 100 1 0 0 18.8 7.85 78 402 7.6 17.5 79 91.8  Minimum 0.2 0.37 0 100 1 0 0 3.4 2.8 36 167 7.1 5 12 16.8  Maximum 0.2 4.5 0.26 100 1 0 0 28.2 13 138 486 8.2 60 420 366  Std. dev. 0 1.36 0.09 — — — — 7.99 3.12 27.5 97.1 0.29 15.9 128 120 

N obs. 14 14 14 1 1 1 1 14 14 14 14 14 14 14 14 

M237.2G Mean 0.2 2.66 0.44 37.5 4 0 0 13.3 10.5 97 397 7.8 27.2 119 155  Median 0.2 2.25 0.43 37.5 4 0 0 11.6 9.9 95 423 7.9 27 51 72.9  Minimum 0.2 0.9 0 5 4 0 0 0.4 6.4 76 150 7 6 11 13.4  Maximum 0.2 6 1.18 70 4 0 0 28.2 15.2 129 478 8.3 64 650 841  Std. dev. 0 1.62 0.42 46 0 0 0 10.1 2.8 14.9 90.2 0.34 15.5 172 212 

N obs. 18 18 17 2 2 2 2 18 18 18 18 18 18 18 18 
E-19

Table E-1. Continued.

Samplinglocation Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Total

suspend

solids

(mg/L)

1996 Near-surface measurements: 

M241.4K Mean 0.2 10.3 — — — — — 14.7 10.6 101 411 8 29.4 69 96.5  Median 0.2 9.85 — — — — — 15.4 10.2 103 420 8 29 36 53.6  Minimum 0.2 6.2 — — — — — 0.3 6.8 78 272 7.5 6 12 15.3  Maximum 0.2 14.6 — — — — — 27.6 15.1 122 485 8.4 63 320 392  Std. dev. 0 2.17 — — — — — 9.79 2.62 13.1 56 0.28 14 82.4 99.2 

N obs. 22 22 0 0 0 0 0 22 22 22 22 22 22 22 22 

MO02.0X Mean 0.2 6.8 — 5 5 0 0 14.3 9.51 89 615 7.8 17 264 476  Median 0.2 6 — 5 5 0 0 13.4 9.1 91 620 7.8 13 120 192  Minimum 0.2 3.4 — 5 5 0 0 0.2 5 54 370 7.4 2 19 25.4  Maximum 0.2 12 — 5 5 0 0 28.2 15.1 116 770 8.2 60 1600 2909  Std. dev. 0 2.45 — — — — — 9.67 2.79 12.2 105 0.2 13.5 367 687 

N obs. 25 25 0 1 1 1 1 25 25 25 25 25 25 25 25 

PE01.8M Mean 0.2 1.42 — 65 10 30 0 13.2 9.15 82 447 7.5 — 47 55.5  Median 0.2 1.38 — 90 10 0 0 13.7 9.3 81 474 7.4 — 31 37.2  Minimum 0.2 0.8 — 5 2 0 0 0.2 3.9 48 273 7.2 — 3 4.5  Maximum 0.2 2.2 — 100 17 90 1 30.1 14.4 135 597 8.3 — 130 244  Std. dev. 0 0.43 — 52.2 7.51 52 .58 10.2 3.51 23.3 99.3 0.29 — 40.4 57.1 

N obs. 21 20 0 3 3 3 3 21 21 21 21 19 0 21 21 

PI00.2M Mean 0.2 3.06 — 79 8 17 1 13.7 8.58 82 530 7.7 44.3 91 112  Median 0.2 3.03 — 90 4 0 0 14.8 7.8 78 535 7.7 35.5 24 26.8  Minimum 0.2 2.1 — 30 1 0 0 0.1 4.9 49 143 7.2 5 5 4.2  Maximum 0.2 3.9 — 100 21 80 4 28.7 13.5 161 701 8.2 143 950 1609  Std. dev. 0 0.55 — 29.2 7.97 35.3 1.7 9.99 2.37 23.9 144 0.27 39.6 196 321 

N obs. 25 14 0 5 5 5 5 25 25 25 25 24 14 25 25 

WD00.2M Mean 0.2 3.22 0.7 20 1 0 0 14.4 9.34 88 660 7.6 37.9 119 169  Median 0.2 2.6 0.7 20 1 0 0 11.2 9.05 91 682 7.6 34 32 34.1  Minimum 0.2 0.64 0.7 20 1 0 0 0.7 5.2 65 202 7.4 5 6 8.9  Maximum 0.2 9.2 0.7 20 1 0 0 27 13.2 108 1131 8 93 920 1692  Std. dev. 0 2.5 — — — — — 9.05 2.66 11.7 264 0.15 28.9 241 442 

N obs. 14 14 1 1 1 1 1 14 14 14 14 14 13 14 14 
E-20

Table E-1. Continued.

Samplinglocation Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Total

suspend

solids

(mg/L)

1996 Near-bottom measurements: 

M201.7Q Mean 4.29 4.49 — — — — — 13.4 9.47 85 433 7.8 — 57 56.8  Median 4.4 4.6 — — — — — 12.9 9.8 93 433 7.8 — 56 52.3  Minimum 2.8 3 — — — — — 0.4 3.3 40 263 7.3 — 35 41.5  Maximum 6.2 6.4 — — — — — 27.7 14 111 566 8.2 — 79 81.2  Std. dev. 0.83 0.83 — — — — — 9.61 3.45 17 63.8 0.23 — 22.7 17.5 

N obs. 25 25 0 — — — — 25 25 25 23 23 — 4 4 

M202.2N Mean 2.17 2.37 — — — — — 13.9 10 93 429 8 — — —  Median 2.2 2.4 — — — — — 12.2 9.9 92 437 8.1 — — —  Minimum 1 1.27 — — — — — 1.2 5.1 64 262 7.3 — — —  Maximum 5 5.2 — — — — — 27.6 15.3 145 566 8.3 — — —  Std. dev. 0.81 0.8 — — — — — 9.31 3.19 19.9 60.5 0.27 — — — 

N obs. 23 23 0 — — — — 23 23 23 21 21 — 0 0 

M206.0S Mean 1.14 1.36 — — — — — 12.3 12.3 108 400 8.3 — 44 54.2  Median 0.9 1.12 — — — — — 16.6 12.1 109 413 8.6 — 44 54.2  Minimum 0.8 1 — — — — — 1.3 5.1 52 262 7.1 — 44 54.2  Maximum 2.5 2.7 — — — — — 26.3 25 178 523 8.9 — 44 54.2  Std. dev. 0.54 0.53 — — — — — 8.87 5.59 33.8 70.5 0.6 — — — 

N obs. 14 14 0 — — — — 14 14 14 13 13 — 1 1 

M235.5D Mean 2.44 2.64 — — — — — 19.3 4.59 47 349 7.2 — 195 187  Median 1.8 2 — — — — — 19.5 3.3 39 387 7.3 — 59 52.8  Minimum 1.3 1.5 — — — — — 10.3 0.3 4 151 6.9 — 35 37.1  Maximum 4.3 4.5 — — — — — 26.1 8.6 80 483 7.5 — 490 471  Std. dev. 1.21 1.21 — — — — — 5.89 3.28 29.8 133 0.21 — 256 246 

N obs. 7 7 0 — — — — 7 7 7 7 7 — 3 3 

M237.2G Mean 1.87 2.08 — — — — — 13.6 10.9 99 437 7.9 — — —  Median 1.9 2.1 — — — — — 8.3 12.3 98 438 8 — — —  Minimum 1 1.2 — — — — — 0.5 6.4 79 384 7.5 — — —  Maximum 3.2 3.4 — — — — — 27.5 15.2 121 474 8.3 — — —  Std. dev. 0.7 0.7 — — — — — 11.4 3.18 12.8 29.2 0.22 — — — 

N obs. 12 12 0 — — — — 12 12 12 12 12 — 0 0 
E-21

Table E-2. Annual summaries (1993–1996) of chemical measurements at fixed sites grouped into near-surface (less than or equal to 0.2 m belo

(less than or equal to 0.2 m above the substrate) categories. Below-surface chemical samples are infrequently collected.

Samplinglocation Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sodi

 (mg

1993 Near-surface measurements: 

BC04.6M Mean 2.01 0.09 0.94 0.077 0.038 5.37 64.2 2.77 — —  Median 1.87 0.05 0.83 0.068 0.029 5.7 51.2 2.43 — —  Minimum 1.24 -0.02 0.71 0.028 0.01 2.16 49.7 1.9 — —  Maximum 3.01 0.3 1.54 0.14 0.092 7.15 85.3 4.3 — —  Std. dev. 0.531 0.097 0.283 0.038 0.024 1.345 16.95 0.808 — — 

N obs. 8 10 10 8 10 10 4 9 0 0 

CA00.4M Mean 2.92 0.1 1.8 0.21 0.1 5.28 64.8 3.99 — —  Median 2.82 0.09 1.45 0.18 0.086 5.38 58.4 3.7 — —  Minimum 1.21 0.04 0.75 0.1 0.03 2.64 53.2 2.9 — —  Maximum 4.62 0.3 3.61 0.32 0.25 7.21 75 5.4 — —  Std. dev. 0.965 0.07 0.924 0.078 0.066 1.367 10.63 0.855 — — 

N obs. 10 12 12 10 12 12 4 9 0 0 

CU11.6M Mean 3.24 0.1 1.19 0.17 0.088 4.82 50.3 4.28 — —  Median 2.97 0.1 0.99 0.15 0.083 4.55 42.4 4.4 — —  Minimum 1.7 0.09 0.48 0.061 -0.01 3.45 30.2 3.1 — —  Maximum 6.35 0.2 3.37 0.37 0.23 6.89 65 5.3 — —  Std. dev. 1.287 0.044 0.761 0.095 0.066 1.118 16.96 0.661 — — 

N obs. 9 12 12 9 12 12 4 9 0 0 

DC01.0M Mean 3.3 0.2 1.14 0.24 0.075 3.93 47 3.98 — —  Median 3.01 0.1 1.07 0.26 0.066 4.61 36.7 3.7 — —  Minimum 2.02 0.08 0.27 0.067 0.024 0.91 33.6 3.3 — —  Maximum 4.27 0.3 2.52 0.34 0.18 5.63 63.3 5.18 — —  Std. dev. 1.004 0.087 0.724 0.091 0.051 1.945 14.21 0.747 — — 

N obs. 6 7 7 6 7 7 4 5 0 0 

I005.7M Mean 5.07 0.07 3.2 0.22 0.11 3.17 47.6 3.26 — —  Median 4.99 0.06 2.99 0.2 0.12 3.73 50 3 — —  Minimum 3.1 -0.02 0.93 0.13 -0.01 0.14 34.1 2.9 — —  Maximum 8.19 0.1 5.35 0.45 0.16 5.31 58.8 4 — —  Std. dev. 1.563 0.055 1.274 0.096 0.053 1.887 12.52 0.393 — — 

N obs. 9 10 10 9 10 10 3 8 0 0 

I007.0W Mean 6.01 0.1 4.15 0.24 0.37 3.73 63.8 3.49 — —  Median 5.97 0.1 3.87 0.23 0.14 4.14 57.4 3.4 — —  Minimum 3.72 -0.02 -0.01 0.14 0.07 0.79 45.7 2.7 — —  Maximum 9.33 0.2 6.73 0.45 3.82 5.03 101 5.08 — —  Std. dev. 1.539 0.068 1.808 0.08 0.922 1.138 17.13 0.66 — — 

N obs. 13 15 16 13 16 15 8 13 0 0 
E-22

Table E-2. Continued.

Samplinglocation Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sodi

 (mg

1993 Near-surface measurements: 

M193.2F Mean 3.18 0.05 1.97 0.29 0.094 5.41 50.1 5 — —  Median 3.04 0.04 1.78 0.26 0.08 5.69 50.8 5 — —  Minimum 1.82 0.03 0.76 0.15 0.038 4.1 31 3.97 — —  Maximum 5.17 0.1 2.95 0.6 0.19 6.59 59.8 6.24 — —  Std. dev. 1.062 0.032 0.709 0.14 0.044 0.742 13.39 0.78 — — 

N obs. 9 12 12 9 12 12 4 9 0 0 

M196.9Q Mean 4.22 0.05 2.99 0.19 0.085 4.16 47.4 3.13 — —  Median 4.39 0.04 2.73 0.17 0.095 4.23 44 3.1 — —  Minimum 2.18 -0.02 1.78 0.087 -0.01 1.25 43.1 2.5 — —  Maximum 5.47 0.1 4.46 0.31 0.17 5.61 52.8 3.7 — —  Std. dev. 0.943 0.035 0.841 0.082 0.049 1.199 4.634 0.435 — — 

N obs. 10 12 12 10 12 12 4 9 0 0 

M201.7Q Mean 3.67 0.06 2.31 0.16 0.056 3.67 50.1 3.47 — —  Median 3.76 0.05 2.08 0.16 0.032 3.2 48.4 3.41 — —  Minimum 1.77 -0.02 1 0.063 0.016 2.24 37.1 2.9 — —  Maximum 5.34 0.1 3.51 0.3 0.13 6.33 63.8 4.04 — —  Std. dev. 1.019 0.036 0.741 0.068 0.04 1.356 10.94 0.424 — — 

N obs. 9 10 10 9 10 10 4 7 0 0 

M202.2N Mean 3.72 0.1 2.25 0.17 0.072 3.68 50.4 3.38 — —  Median 3.3 0.1 1.8 0.17 0.067 3.5 52 3.3 — —  Minimum 1.57 0.03 0.9 0.062 0.01 1.9 35.9 2.98 — —  Maximum 7.24 0.2 3.93 0.3 0.13 6.17 60.3 4.2 — —  Std. dev. 1.62 0.058 1.071 0.078 0.043 1.349 10.31 0.423 — — 

N obs. 9 12 12 9 12 12 4 9 0 0 

M203.5R Mean 4.57 0.1 3.14 0.21 0.11 4.56 — 3.53 — —  Median 4.57 0.08 3.37 0.16 0.11 4.48 — 3.4 — —  Minimum 1.6 0.04 0.9 0.14 0.061 3.89 — 3.1 — —  Maximum 6.98 0.3 4.27 0.27 0.18 5.32 — 4.1 — —  Std. dev. 2.232 0.078 1.251 0.066 0.04 0.502 — 0.419 — — 

N obs. 4 6 6 4 6 6 0 4 0 0 

M206.0S Mean 3.74 0.08 2.12 0.19 0.75 4.88 — 3.48 — —  Median 3.68 0.06 2.44 0.19 0.091 4.64 — 3.3 — —  Minimum 1.98 0.03 -0.01 0.11 0.034 3.89 — 3.1 — —  Maximum 5.13 0.1 3.9 0.29 4.74 5.78 — 4 — —  Std. dev. 1.186 0.042 1.346 0.067 1.76 0.652 — 0.386 — — 

N obs. 5 6 7 5 7 6 0 4 0 0 
E-23

Table E-2. Continued.

Samplinglocation Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sodi

 (mg

1993 Near-surface measurements: 

M206.1T Mean 3.4 0.04 1.92 0.18 0.075 3.62 36.8 3.53 — —  Median 2.52 0.04 1.26 0.14 0.087 3.93 37.5 3.5 — —  Minimum 2.5 -0.02 0.12 0.12 -0.01 0.9 32.9 3 — —  Maximum 6.13 0.07 3.96 0.3 0.18 6.17 40.1 4 — —  Std. dev. 1.475 0.025 1.678 0.066 0.062 2.027 3.646 0.399 — — 

N obs. 6 8 8 6 8 8 3 7 0 0 

M235.5D Mean 3.2 0.07 2.12 0.18 0.56 5.15 50 3.29 — —  Median 2.58 0.06 2.55 0.17 0.093 5.02 46.1 3.3 — —  Minimum 0.13 -0.02 -0.01 0.082 -0.01 3.9 44.6 2.64 — —  Maximum 6.11 0.1 4.37 0.32 4.8 6.39 56.3 4.42 — —  Std. dev. 1.947 0.048 1.866 0.071 1.49 0.827 5.551 0.533 — — 

N obs. 8 9 10 8 10 9 4 8 0 0 

M237.2G Mean 4.41 0.1 2.74 0.19 0.4 4.41 47.4 3.36 — —  Median 4.5 0.05 2.59 0.17 0.11 4.31 47 3.2 — —  Minimum 2.57 -0.02 -0.01 0.084 -0.01 1.5 37.4 2.72 — —  Maximum 6.43 0.7 4.48 0.32 4.75 6.43 56.8 4.9 — —  Std. dev. 1.078 0.215 1.02 0.074 1.204 1.239 7.776 0.679 — — 

N obs. 11 14 15 12 15 14 7 12 0 0 

M241.4K Mean 4.9 0.2 2.71 0.2 0.38 4.12 51.2 3.32 — —  Median 4.51 0.05 2.66 0.2 0.1 4.2 48.4 3.12 — —  Minimum 2.32 -0.02 -0.01 0.089 -0.01 0.65 37.8 2.42 — —  Maximum 8.33 0.9 4.7 0.37 4.74 6.37 67.5 5.1 — —  Std. dev. 1.815 0.27 1.31 0.076 1.164 1.506 9.356 0.768 — — 

N obs. 12 15 16 13 16 15 8 13 0 0 

MO02.0X Mean 2.96 0.05 1.83 0.25 0.1 5.61 47.9 5.15 — —  Median 2.73 0.04 1.64 0.23 0.089 5.67 48.4 5.1 — —  Minimum 1.54 -0.02 0.79 0.14 0.067 4.35 31.6 4.3 — —  Maximum 3.81 0.1 2.84 0.44 0.19 6.73 58.8 5.92 — —  Std. dev. 0.718 0.039 0.688 0.103 0.036 0.596 11.69 0.613 — — 

N obs. 10 12 12 10 12 12 4 9 0 0 

PE01.8M Mean 3.04 0.1 1.05 0.22 0.06 3.4 36.1 4.55 — —  Median 2.95 0.1 0.78 0.26 0.026 3.48 33 4.5 — —  Minimum 1.89 0.03 0.25 0.14 0.015 1.58 27.2 3.5 — —  Maximum 4.72 0.2 3.52 0.27 0.13 4.88 43.3 5.46 — —  Std. dev. 0.93 0.048 1.118 0.06 0.051 1.304 7.393 0.656 — — 

N obs. 6 7 7 6 7 7 4 6 0 0 
E-24

Table E-2. Continued.

Samplinglocation Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sodi

 (mg

1993 Near-surface measurements: 

PI00.2M Mean 4.17 0.1 2.13 0.18 0.1 5.26 83.6 4.23 — —  Median 3.69 0.1 1.58 0.16 0.073 5.29 77.8 4.18 — —  Minimum 2.24 0.07 0.99 0.1 0.032 2.32 70.1 3 — —  Maximum 6.6 0.3 4.53 0.4 0.21 7.31 106 5.1 — —  Std. dev. 1.38 0.063 1.187 0.088 0.056 1.337 15.3 0.766 — — 

N obs. 9 12 12 9 12 12 4 9 0 0 

WD00.2M Mean 4.06 0.2 2.58 0.38 0.2 5.46 76.8 4.61 — —  Median 3.11 0.1 2.24 0.25 0.18 5.27 69 4.6 — —  Minimum 2.37 -0.02 0.96 0.15 0.09 3.55 60.4 3.3 — —  Maximum 8.38 0.4 6.11 1.27 0.51 8.16 98.3 6.28 — —  Std. dev. 1.833 0.136 1.516 0.336 0.122 1.339 16.3 0.892 — — 

N obs. 10 12 12 10 12 12 4 9 0 0 

1994 Near-surface measurements: 

CA00.4M Mean 1.68 0.07 0.64 0.22 0.032 4.1 61.6 4.62 26 20. Median 1.51 0.07 0.74 0.14 0.021 4.01 66.7 4.35 29.3 2 Minimum 0.69 -0.02 -0.01 0.085 -0.01 1.94 14.3 2.05 3.42 6.5 Maximum 4.38 0.2 1.64 0.59 0.11 5.83 86 11.1 40.1 33. Std. dev. 0.813 0.058 0.504 0.157 0.034 1.038 20.53 1.943 10.16 7.13

N obs. 18 19 19 18 20 20 20 20 19 1

CU11.6M Mean 1.67 0.09 0.73 0.14 0.017 3.14 48.4 4.57 8.97 14. Median 1.28 0.05 0.62 0.083 -0.01 3.15 47.3 4.38 9.35 13. Minimum 0.82 -0.02 0.14 0.011 -0.01 1.12 24.6 2.7 3.75 6.0 Maximum 3.45 0.4 1.81 0.52 0.066 4.61 66.8 8.37 14 24. Std. dev. 0.861 0.115 0.58 0.137 0.017 1.025 14.16 1.28 2.896 4.60

N obs. 16 16 16 16 17 17 17 17 17 1

DC01.0M Mean 4.89 0.2 1.87 0.75 0.36 4.54 45.4 5.74 15 3 Median 3.78 0.2 1.83 0.58 0.22 4.41 44 5.04 15.1 33. Minimum 1.96 -0.02 -0.01 0.16 0.02 2.47 25.5 2.6 6.3 17. Maximum 13 0.7 4.24 1.97 1.54 7.3 79.3 11.6 23.4 76. Std. dev. 3.123 0.184 1.326 0.534 0.402 1.287 14.45 2.503 4.762 16.4

N obs. 19 19 19 19 20 20 20 20 19 1
E-25

Table E-2. Continued.

Samplinglocation Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sodium 

1994 Near-surface measurements: 

I005.7M Mean 3.5 0.1 2.86 0.23 0.083 2.85 58.3 4.14 26.1 31. Median 3.43 0.09 2.79 0.24 0.045 2.56 59.9 4.02 26 29. Minimum 1.6 -0.02 0.77 0.095 -0.01 1.05 41.1 2.46 22.3 1 Maximum 5.15 0.4 5.25 0.36 0.24 4.12 70.2 6.15 33 50. Std. dev. 1.122 0.13 1.583 0.093 0.084 1.087 8.971 1.246 3.429 13.0

N obs. 9 8 8 9 9 9 9 9 9 9 

I007.0W Mean 4.42 0.1 3.05 0.22 0.072 2.31 55.2 4.08 24.2 35. Median 3.84 0.08 3.37 0.22 0.055 1.9 55.8 4.26 23.4 40. Minimum 2.14 -0.02 0.58 0.078 -0.01 0.1 24.6 1.71 9.79 10. Maximum 16.7 0.8 5.29 0.37 0.2 4.02 79.2 7.05 32.5 55. Std. dev. 3.235 0.179 1.37 0.077 0.054 1.095 13.53 1.221 6.22 13.8

N obs. 19 18 18 19 19 19 19 19 19 1

M193.2F Mean 2.24 0.06 1.43 0.24 0.056 4.55 53.9 5.57 17.6 39. Median 1.81 0.02 1.13 0.17 0.043 4.3 53.4 5.76 17.9 38. Minimum 0.71 -0.02 0.57 0.12 -0.01 2.76 27.3 3.55 9.84 20. Maximum 6.89 0.4 3.17 0.6 0.17 7.74 84.8 7.4 24.1 64. Std. dev. 1.352 0.094 0.769 0.147 0.041 1.281 12.03 1.118 3.123 12.9

N obs. 18 19 19 18 20 20 20 20 19 1

M196.9Q Mean 2.97 0.1 2.1 0.21 0.046 3.66 46.9 3.19 18.5 12. Median 2.65 0.02 1.75 0.16 0.037 4.3 47.5 3.21 19.6 12. Minimum 1.68 -0.02 0.86 0.07 -0.01 0.2 10.1 1.08 3.59 3.1 Maximum 4.57 0.8 4.44 0.47 0.16 5.97 70.5 4.47 22.8 28. Std. dev. 0.905 0.201 0.998 0.126 0.042 1.75 11.2 0.765 4.625 4.61

N obs. 18 19 19 18 20 20 20 20 19 1

M201.7Q Mean 2.51 0.08 1.69 0.14 0.028 2.65 45.4 3.2 18.5 1 Median 2.47 0.02 1.98 0.11 0.024 2.46 44.7 3.12 19.8 11. Minimum 1.34 -0.02 0.55 0.031 -0.01 0.51 28.3 2.13 7.99 5.0 Maximum 4.31 0.5 2.82 0.4 0.074 5.32 61.9 4.23 25 24. Std. dev. 0.797 0.142 0.78 0.091 0.025 1.48 8.474 0.599 4.314 3.55

N obs. 20 19 19 20 20 20 20 20 20 2

M202.2N Mean 2.35 0.1 1.33 0.13 0.02 2.47 45.7 3.22 19.3 12. Median 2.13 0.04 1.11 0.099 0.013 1.98 43.8 3.15 20.2 11. Minimum 1.2 -0.02 0.3 0.024 -0.01 0.27 26.9 1.95 7.96 6.6 Maximum 3.8 0.4 2.47 0.39 0.069 5.25 62 4.56 23.4 2 Std. dev. 0.718 0.131 0.785 0.093 0.018 1.598 9.639 0.648 3.832 4.02

N obs. 18 19 19 18 20 20 20 20 20 2
E-26

Table E-2. Continued.

Samplinglocation Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sodium 

1994 Near-surface measurements: 

M203.5R Mean 2.57 0.04 1.78 0.17 0.035 3.27 49.9 3.09 20 12. Median 2.28 0.02 1.58 0.13 0.024 3.21 48.2 3.18 20.6 11. Minimum 1.48 -0.02 0.62 0.074 -0.01 0.65 30 2.31 8.53 9.6 Maximum 4.23 0.2 3.51 0.4 0.088 6.05 74.3 3.87 27.8 23. Std. dev. 0.775 0.048 0.873 0.087 0.028 1.912 10.78 0.434 4.012 3.22

N obs. 14 15 15 14 16 16 16 16 15 1

M206.0S Mean 1.84 0.03 0.78 0.15 0.018 2.37 45.1 3.33 19.3 13. Median 1.83 -0.02 0.67 0.12 0.012 2.16 44.1 3.33 20.1 11. Minimum 1.08 -0.02 -0.01 -0.01 -0.01 0.62 24.9 2.28 6.15 5  Maximum 3.63 0.2 2.63 0.38 0.06 4.27 77.7 4.2 32.7 37. Std. dev. 0.596 0.049 0.628 0.107 0.016 1.111 12.84 0.464 5.78 7.3

N obs. 17 16 16 17 17 17 17 17 17 1

M206.1T Mean 1.68 0.05 0.42 0.26 0.016 3.31 53.7 4.17 20.9 12. Median 1.72 -0.02 0.15 0.19 -0.01 2.86 54.4 4.12 18.4 12. Minimum 0.71 -0.02 -0.01 0.084 -0.01 1.49 27.7 3.18 7.46 7.5 Maximum 2.44 0.2 1.21 0.76 0.069 6 62.8 5.34 56.2 22. Std. dev. 0.54 0.06 0.495 0.185 0.02 1.471 9.587 0.669 12.21 3.75

N obs. 11 10 10 11 11 11 11 11 11 1

M235.5D Mean 1.97 0.1 0.6 0.24 0.015 2.51 44.1 4.36 13.2 8.1 Median 1.69 0.1 0.19 0.18 0.012 2.42 41.4 4.59 12 6.0 Minimum 0.73 -0.02 -0.01 0.059 -0.01 -0.05 25.3 2.8 5.99  Maximum 3.74 0.5 3.75 0.65 0.039 4.42 78.2 5.52 32.8 37. Std. dev. 0.78 0.162 1.069 0.148 0.011 1.39 11.21 0.853 5.659 7.95

N obs. 16 15 15 16 17 17 17 17 17 1

M237.2G Mean 2.86 0.1 2.02 0.21 0.056 3.79 45.8 3.19 18.6 10. Median 2.8 0.03 1.92 0.16 0.039 3.93 47.2 3.09 19.8 10. Minimum 1.04 -0.02 -0.01 0.054 -0.01 0.6 22 1.74 4.08 6.3 Maximum 4.84 0.7 4.56 0.75 0.18 6.27 56.3 4.5 23.2 12. Std. dev. 0.979 0.176 1.193 0.16 0.053 1.806 7.925 0.656 4.381 1.61

N obs. 18 17 17 18 19 19 19 19 19 1

M241.4K Mean 2.98 0.09 2.06 0.21 0.054 3.7 48.8 3.18 20.3 11. Median 2.94 -0.02 1.87 0.17 0.041 4.23 48.3 3.18 21.1 1 Minimum 1.18 -0.02 0.6 0.082 -0.01 0.39 35.2 2.28 13.3 6. Maximum 5.16 0.6 4.12 0.46 0.17 6.22 71.8 4.65 25.5 1 Std. dev. 1.069 0.175 1.042 0.104 0.044 1.947 7.39 0.643 2.694 1.76

N obs. 17 17 17 17 19 19 19 19 19 1
E-27

Table E-2. Continued.

Samplinglocation Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sodium 

1994 Near-surface measurements: 

MO02.0X Mean 1.86 0.05 1.3 0.25 0.048 4.75 54.6 5.7 18.6 41. Median 1.73 -0.02 1.12 0.15 0.046 4.34 54.3 5.91 18.5 3 Minimum 0.92 -0.02 0.52 0.094 -0.01 2.87 15.4 3.9 9.08 21. Maximum 3.12 0.5 2.41 1.02 0.11 7.93 83.8 7.7 36.1 64. Std. dev. 0.657 0.104 0.604 0.242 0.03 1.274 15.32 1.19 5.648 14.0

N obs. 17 19 19 18 20 20 20 20 19 1

PE01.8M Mean 1.5 0.05 0.66 0.12 0.013 3.36 50.7 4.26 11.6 21. Median 1.32 0.05 0.65 0.087 -0.01 2.95 49.8 4.38 11.8 19. Minimum 0.85 -0.02 -0.01 0.053 -0.01 1.68 10.3 2.37 1.55 2.6 Maximum 3.79 0.1 1.34 0.29 0.044 7.73 84.1 5.76 31.5 60. Std. dev. 0.792 0.034 0.394 0.069 0.011 1.342 15.02 1.046 5.86 11.7

N obs. 17 17 17 17 19 19 18 18 17 1

PI00.2M Mean 2.18 0.1 1.29 0.2 0.038 3.53 59.6 4.08 24.7 20. Median 2.06 0.08 1.29 0.12 0.024 3.38 55.3 3.87 22.2 20. Minimum 0.96 -0.02 0.54 0.05 -0.01 1 24.9 1.95 7.05 7.9 Maximum 5.3 0.3 2.57 1.33 0.18 5.99 90.4 10.3 39.3 2 Std. dev. 1.035 0.104 0.507 0.282 0.042 1.339 18.54 1.778 8.453 5.12

N obs. 19 19 19 19 20 20 20 20 20 2

WD00.2M Mean 2.3 0.3 1.58 0.33 0.2 3.86 76.9 4.55 32.8 29. Median 1.59 0.08 0.77 0.16 0.097 3.57 85.8 3.87 38.6 32. Minimum 1.17 -0.02 0.71 0.088 0.027 0.083 42.8 2.5 11.2 4.1 Maximum 5.6 0.9 4.49 1 0.81 7.38 98 7.59 45.9 42. Std. dev. 1.666 0.32 1.462 0.342 0.302 2.358 22.58 1.848 14.01 14.7

N obs. 6 6 6 6 6 6 6 6 6 6 

1995 Near-surface measurements: 

CA00.4M Mean 2.23 0.1 0.88 0.25 0.043 4.13 64 4.78 26.1 20. Median 1.83 0.1 0.35 0.15 0.02 3.89 64.6 4.44 27.4 21. Minimum 0.87 -0.02 0.051 0.058 -0.01 1.11 24.7 3.42 8.58 9.7 Maximum 4.68 0.5 3.86 1.55 0.39 6.73 83.5 7.14 39.2 32. Std. dev. 0.978 0.11 0.991 0.335 0.081 1.648 16.45 1.018 7.987 6.5

N obs. 24 24 24 24 23 22 24 24 24 2
E-28

Table E-2. Continued.

Samplinglocation Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sodium 

1995 Near-surface measurements: 

CU11.6M Mean 2.19 0.1 0.85 0.2 0.034 3.53 47.8 4.25 9.03 12. Median 1.94 0.1 0.78 0.091 0.013 3.68 52.1 4.05 8.71 12. Minimum 1.05 -0.02 0.02 0.02 -0.01 0.35 22.2 2.85 3.78 5.3 Maximum 4.99 0.3 2.19 1.61 0.17 5.27 67.9 6.33 25.3 23. Std. dev. 1.171 0.074 0.667 0.353 0.046 1.597 14.61 1.012 4.805 4.64

N obs. 19 19 19 19 19 18 19 19 19 1

DC01.0M Mean 5.27 0.1 3.71 0.7 0.47 4.1 45.5 5.17 15.5 38. Median 3.99 0.1 2.65 0.39 0.19 4.07 44.6 4.5 15 30. Minimum 1.63 -0.02 0.13 0.13 0.028 -0.05 13.2 2.4 3.13 6.5 Maximum 11 0.5 10.6 2.47 1.84 7.1 72.8 8.64 26.4 10 Std. dev. 3.022 0.103 2.952 0.635 0.534 1.77 15 1.561 6.765 25.2

N obs. 23 24 24 23 24 23 24 24 24 2

I005.7M Mean 3.98 0.09 2.98 0.28 0.088 2.16 58.1 3.74 25.6 30. Median 3.89 0.05 2.66 0.26 0.072 2.16 56.2 3.75 25.7 34. Minimum 2.42 0.02 1.1 0.12 -0.01 0.24 49.6 2.73 21.5 1 Maximum 6.44 0.3 5.35 0.58 0.22 3.92 78.5 4.5 33.6 46. Std. dev. 1.071 0.073 1.304 0.13 0.072 1.194 7.326 0.516 2.892 10.9

N obs. 13 13 13 13 13 13 13 13 13 1

I007.0W Mean 5.26 0.09 3.68 0.3 0.1 2.72 63.7 3.9 27.2 34. Median 4.93 0.06 3.82 0.24 0.1 2.67 62 3.84 26.7 36. Minimum 2.34 0.03 1.14 0.13 -0.01 0.65 5.02 3.12 2.03 1.3 Maximum 19.3 0.3 5.73 0.94 0.21 4.06 93.4 4.95 37.4 57. Std. dev. 3.315 0.064 1.451 0.186 0.044 0.894 15.77 0.481 6.604 11.8

N obs. 24 24 24 24 24 23 24 24 24 2

M193.2F Mean 2.65 0.05 1.57 0.24 0.053 4.86 56.9 5.36 19.6 37. Median 2.48 0.04 1.42 0.23 0.045 5.18 57.7 5.07 20.8 3 Minimum 1.32 0.03 0.61 0.065 0.019 1.6 42.5 3.51 12.5 13. Maximum 4.76 0.1 3.75 1.02 0.16 6.36 73.6 8.9 26.1 72. Std. dev. 0.845 0.03 0.765 0.191 0.028 1.155 8.179 1.247 3.616 15.8

N obs. 25 25 25 25 24 23 25 25 25 2

M196.9Q Mean 3.44 0.05 2.57 0.19 0.055 4.33 51.4 3.12 21 13. Median 3.46 0.04 2.73 0.18 0.056 4.6 51.5 3.15 21.7 12. Minimum 1.44 -0.02 0.71 0.073 -0.01 0.91 21.4 2.13 10.6 5.0 Maximum 6.33 0.1 4.46 0.33 0.2 6.13 71.1 4.26 28.3 21. Std. dev. 1.161 0.031 1.126 0.073 0.04 1.283 10.47 0.589 4.257 4.25

N obs. 25 25 25 25 24 23 25 25 25 2
E-29

Table E-2. Continued.

Samplinglocation Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sodium 

1995 Near-surface measurements: 

M201.7Q Mean 2.84 0.05 1.93 0.14 0.03 3.5 49.5 3.33 20.4 11. Median 2.79 0.04 1.83 0.13 0.024 3.9 49.4 3.18 19.8 10. Minimum 1.41 -0.02 0.61 0.075 -0.01 0.62 36.6 1.89 15.4 7. Maximum 4.83 0.2 3.83 0.31 0.075 5.73 60.9 4.89 25.3 16. Std. dev. 0.835 0.036 0.902 0.054 0.021 1.673 7.133 0.761 3.074 2.47

N obs. 22 22 22 22 22 21 22 22 22 2

M202.2N Mean 2.7 0.05 1.53 0.13 0.028 3.36 49 3.34 20.1 11. Median 2.69 0.06 1.66 0.14 0.021 3.75 49.6 3.3 19.7 11. Minimum 1.57 -0.02 -0.01 0.062 -0.01 0.23 38.5 2.34 15.4 7.8 Maximum 4.08 0.2 2.95 0.22 0.073 5.79 60.7 5.61 24.9 16. Std. dev. 0.712 0.041 0.913 0.047 0.02 1.695 6.544 0.752 2.905 2.67

N obs. 21 21 21 21 21 20 21 21 21 2

M202.6T Mean 3.01 0.05 2.01 0.16 0.061 4.64 48.6 3.06 20.6 11. Median 2.75 0.03 1.65 0.14 0.054 4.88 47.7 3.03 20.2 11. Minimum 1.49 -0.02 0.69 0.079 0.012 1.68 34.2 1.92 10.4 6.5 Maximum 4.97 0.2 4.12 0.27 0.11 5.9 63.6 5.01 27.8 17. Std. dev. 1.053 0.042 1.114 0.055 0.026 1.118 9.617 0.855 5.139 2.9

N obs. 16 16 16 16 16 15 16 16 16 1

M203.5R Mean 3.13 0.04 2.09 0.17 0.045 4.3 50.8 3.06 21 15. Median 2.8 0.03 2.37 0.17 0.045 4.64 51.1 2.94 21.5 12. Minimum 1.47 -0.02 0.63 0.096 -0.01 2.06 34.2 1.8 15.2 7.4 Maximum 7.15 0.1 4.26 0.29 0.095 5.88 62.6 5.28 27.1 64. Std. dev. 1.433 0.03 1.053 0.057 0.025 1.213 8.887 0.817 4.022 13.0

N obs. 16 17 17 16 17 16 17 17 17 1

M206.0S Mean 2.31 0.04 0.92 0.16 0.022 3.08 48.6 3.68 20.1 13. Median 1.96 0.03 0.29 0.17 0.014 3.48 47.4 3.66 19.6 1 Minimum 1.22 -0.02 -0.01 0.037 -0.01 -0.05 37.6 2.28 14.7 7.6 Maximum 4.58 0.1 4.29 0.28 0.069 5.9 63.1 6.09 29 5 Std. dev. 1.021 0.037 1.233 0.066 0.019 2.011 6.652 0.864 3.359 8.93

N obs. 24 24 24 24 24 23 24 24 24 2

M206.1T Mean 1.62 0.04 0.42 0.13 0.018 2.38 57.2 5.55 18.5 10. Median 1.43 0.04 0.14 0.13 -0.01 1.24 55.9 5.34 17.6 8. Minimum 0.84 -0.02 -0.01 0.054 -0.01 0.51 42.6 4.56 14.4 7.0 Maximum 2.92 0.09 2.15 0.18 0.057 7.44 75.5 7.56 25.5 13. Std. dev. 0.713 0.027 0.745 0.034 0.02 2.287 9.993 0.878 3.91 2.64

N obs. 12 12 12 12 11 11 12 12 12 1
E-30

Table E-2. Continued.

Samplinglocation Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sodium 

1995 Near-surface measurements: 

M235.5D Mean 2.43 0.1 0.46 0.27 0.016 2.37 47.6 3.55 14.9 7.4 Median 2.45 0.04 0.13 0.21 -0.01 2.15 49.2 3.57 14.9 7.3 Minimum 1.13 -0.02 -0.01 0.075 -0.01 -0.05 20.1 2.31 3.55 2.4 Maximum 4.41 0.6 3.47 1.07 0.071 6.26 64.6 4.95 22.3 14. Std. dev. 0.867 0.178 0.913 0.222 0.02 1.974 10.34 0.668 4.595 3.04

N obs. 23 24 24 23 24 23 24 24 24 2

M237.2G Mean 3.77 0.05 2.42 0.2 0.052 4.54 45.8 3.24 18.1 10. Median 3.07 0.04 1.93 0.19 0.043 4.67 48.5 3.15 18.8 9.1 Minimum 1.89 -0.02 0.39 0.099 -0.01 1.54 -0.01 1.98 0.063 1.6 Maximum 8.94 0.2 4.88 0.4 0.12 6.01 59.2 5.28 27.2 15. Std. dev. 1.936 0.038 1.487 0.061 0.032 1.103 14.08 0.686 6.587 3.22

N obs. 19 20 20 19 20 19 20 20 20 2

M241.4K Mean 3.49 0.04 2.5 0.17 0.047 4.22 51.9 3.21 22.3 12. Median 3.37 0.03 2.51 0.18 0.049 4.16 52.3 3 22.5 12. Minimum 1.62 -0.02 0.7 0.059 -0.01 0.76 35.9 2.04 16.8 7.4 Maximum 6.47 0.1 5.02 0.28 0.1 6.44 66.7 6.78 28 18. Std. dev. 1.333 0.028 1.303 0.062 0.031 1.539 8.259 1.165 3.317 2.96

N obs. 21 23 23 21 23 22 23 23 23 2

MO02.0X Mean 2.19 0.05 1.19 0.31 0.046 5.33 59.8 5.74 19.2 47. Median 1.81 0.05 1.11 0.18 0.047 5.47 62.1 5.55 20 47. Minimum -0.1 0.02 0.57 -0.01 0.017 0.91 45.3 4.14 12.7 19. Maximum 4.24 0.2 1.96 1.09 0.085 6.68 73.4 10.2 25.5 75. Std. dev. 0.982 0.035 0.418 0.308 0.015 1.131 8.72 1.226 3.984 16.

N obs. 25 25 24 25 24 23 25 25 25 2

PE01.8M Mean 1.5 0.08 0.46 0.19 0.026 3.26 50.5 3.92 11.6 21. Median 1.51 0.06 0.43 0.13 0.014 3.48 50.2 3.84 10.8 2 Minimum 0.44 -0.02 -0.01 0.034 -0.01 0.72 3.06 2.97 0.47 0.4 Maximum 2.93 0.3 1.15 1.55 0.17 4.79 81.9 4.71 21.8 38. Std. dev. 0.639 0.071 0.423 0.296 0.035 1.09 18.06 0.5 4.939 8.80

N obs. 24 24 24 24 24 23 24 24 24 2

PI00.2M Mean 2.69 0.1 1.41 0.21 0.05 4.12 63.6 4.26 25.2 19. Median 2.17 0.09 0.93 0.13 0.038 4.21 60.4 4.11 24 17. Minimum 0.98 -0.02 0.35 0.044 -0.01 1.36 27.7 2.79 8.57 9.9 Maximum 5.5 0.3 4.09 1.4 0.16 6.25 90.5 6.51 36.6 48. Std. dev. 1.26 0.082 1.078 0.278 0.041 1.208 16.09 1.077 6.734 7.59

N obs. 22 22 22 22 22 21 22 22 22 2
E-31

Table E-2. Continued.

Samplinglocation Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sodium 

1995 Near-surface measurements: 

WD00.2M Mean 4.75 0.7 3.15 0.66 0.48 5.43 68.9 6.88 28.1 41. Median 3.97 0.3 2.64 0.37 0.19 5.32 64.9 5.58 25.9 30. Minimum 1.29 0.04 0.4 0.1 0.024 2.13 43.9 3.27 17 1 Maximum 9.38 3.3 5.81 2.06 1.45 8.01 101 26.6 40.9 79. Std. dev. 2.327 0.93 1.647 0.575 0.489 1.663 13.73 5.126 6.142 21.0

N obs. 18 18 18 18 17 16 18 18 18 1

1996 Near-surface measurements: 

CA00.4M Mean 2.33 0.2 0.93 0.45 0.054 3.43 58.3 5.65 23.3 23. Median 2.02 0.1 0.76 0.16 0.021 3.54 54.1 5.25 22.2 20. Minimum 0.8 -0.02 -0.01 0.09 -0.01 0.72 18.3 3.12 5.24 9.6 Maximum 6.57 0.6 2.52 2.38 0.26 5.36 89.2 9.27 42.7 58. Std. dev. 1.329 0.161 0.808 0.644 0.07 1.171 19.39 1.327 9.601 11.5

N obs. 21 17 22 14 22 22 22 22 22 2

CU11.6M Mean 2.72 0.1 1.38 0.46 0.038 3.03 41.1 5.56 7.04 12. Median 2.36 0.08 1.16 0.26 0.022 3.34 41.5 5.4 7.09 1 Minimum 0.87 -0.02 0.37 0.022 -0.01 -0.05 19.3 3 3.09 5.2 Maximum 5.66 0.3 3.21 1.11 0.14 4.43 63.6 9 11.3 17. Std. dev. 1.455 0.099 0.863 0.435 0.036 1.207 13.92 1.383 2.409 4.54

N obs. 14 11 15 10 15 15 15 15 15 1

DC01.0M Mean 3.33 0.5 1.31 0.52 0.47 4.7 46.4 7.1 15.6 52. Median 2.24 0.2 0.67 0.38 0.4 5.24 43.2 6.63 14.3 42. Minimum 1.32 0.03 0.077 0.16 0.017 1.4 20.8 3.12 5.34 6.8 Maximum 12.5 2.5 6.04 1.56 1.55 8.06 74.5 14.3 28.2 21 Std. dev. 2.541 0.542 1.493 0.388 0.411 1.826 14.63 2.775 6.554 45.3

N obs. 23 20 23 14 23 23 23 23 23 2

I005.7M Mean 3.77 0.06 2.52 0.3 0.054 1.75 62.6 4.72 27.5 3 Median 3.62 0.05 2.31 0.24 0.05 1.88 60.2 4.5 25.4 38. Minimum 0.68 -0.02 -0.01 0.14 -0.01 -0.05 33.7 3.75 15.9 12. Maximum 5.64 0.2 5.02 0.76 0.14 2.89 151 6.15 69.2 92. Std. dev. 1.399 0.057 1.521 0.172 0.034 0.925 27.62 0.708 12.36 23.3

N obs. 15 10 15 11 15 15 15 15 15 1
E-32

Table E-2. Continued.

Samplinglocation Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sodium 

1996 Near-surface measurements: 

I007.0W Mean 4.47 0.1 3.35 0.33 0.12 2.22 60.9 4.82 24.3 4 Median 4.23 0.05 3.18 0.27 0.1 2.39 63.6 4.59 24.8 45. Minimum 2.15 -0.02 1.51 0.14 0.031 0.83 26.5 3.18 9.71 11. Maximum 12.9 0.6 6.65 0.75 0.24 3.7 81.6 7.29 36.6 69. Std. dev. 2.244 0.192 1.331 0.148 0.058 0.736 13.78 1.061 6.264 19.4

N obs. 22 18 23 14 23 23 23 23 23 2

M193.2F Mean 2.68 0.08 1.61 0.36 0.044 4.46 53.2 5.54 17.9 34. Median 2.7 0.02 1.67 0.25 0.04 4.52 53.2 5.49 17.8 35. Minimum 1.17 -0.02 0.58 0.055 -0.01 2.76 27.5 3.12 9.36 21. Maximum 5.61 0.3 3 1.38 0.15 6.48 73.8 7.68 27.2 56. Std. dev. 1.077 0.092 0.668 0.365 0.031 1.026 10.24 0.975 4.154 9.1

N obs. 24 20 25 15 25 25 25 25 25 2

M196.9Q Mean 3.07 0.1 2.19 0.22 0.047 3.55 48.5 3.86 19.6 13. Median 3.23 0.05 2.17 0.19 0.034 3.62 46.3 3.93 20.1 12. Minimum 1.21 -0.02 0.63 0.077 0.012 0.12 21.4 2.1 9.3 5.0 Maximum 4.37 0.5 3.9 0.48 0.2 6.14 64.5 5.4 28.8 22. Std. dev. 0.982 0.146 0.994 0.12 0.039 1.769 10.82 0.744 4.93 4.67

N obs. 25 21 26 17 26 26 26 26 26 2

M201.7Q Mean 2.83 0.09 2 0.17 0.039 3.13 45.5 4.18 18.2 11. Median 3.11 0.04 1.96 0.14 0.028 3.07 45.1 4.05 19.2 1 Minimum 1.19 -0.02 0.6 0.085 -0.01 0.48 20.1 2.55 9.05 5.1 Maximum 4.24 0.5 4.72 0.56 0.21 5.83 63 10.1 26.3 1 Std. dev. 0.976 0.113 1.038 0.115 0.043 1.472 9.796 1.417 4.046 3.63

N obs. 24 20 25 15 25 25 25 25 25 2

M202.2N Mean 2.6 0.05 1.77 0.16 0.028 2.95 45.1 3.88 18.2 1 Median 2.74 0.04 1.75 0.13 0.016 2.99 44.8 3.75 19.5 1 Minimum 0.99 -0.02 0.54 0.077 -0.01 0.59 19.5 2.58 9.24 4.8 Maximum 3.87 0.2 3.08 0.29 0.077 5.35 62.8 5.13 26.7 17. Std. dev. 0.908 0.052 0.839 0.06 0.023 1.204 10.78 0.736 4.416 3.69

N obs. 24 18 24 16 24 24 24 24 24 2

M202.6T Mean 2.97 0.1 2.1 0.26 0.049 3.53 44.6 3.91 17.7 10. Median 3.01 0.04 2.03 0.19 0.036 3.87 43.4 3.93 18.6 10. Minimum 0.86 -0.02 0.71 0.12 -0.01 0.11 20 2.7 8.74 4.9 Maximum 4.58 0.6 4 0.71 0.21 6.15 62.5 5.19 23.9 1 Std. dev. 1.124 0.15 1.021 0.192 0.042 1.761 11.2 0.698 4.39 3.19

N obs. 24 19 24 15 24 24 24 24 24 2
E-33

Table E-2. Continued.

Samplinglocation Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sodium 

1996 Near-surface measurements: 

M203.5R Mean 2.97 0.1 2.07 0.23 0.048 3.88 46.9 3.82 18.9 11. Median 3.09 0.05 2.09 0.16 0.038 4.23 46.6 3.9 19.1 11. Minimum 1.44 -0.02 0.65 0.078 -0.01 0.19 20.4 2.37 8.85 5. Maximum 4.22 0.5 3.63 0.7 0.24 6.08 64.1 5.64 28.9 16. Std. dev. 0.887 0.152 0.844 0.172 0.051 1.624 10.85 0.908 4.904 2.86

N obs. 20 16 20 15 20 20 20 20 20 2

M206.0S Mean 1.98 0.02 0.61 0.19 0.015 1.74 42.8 3.89 18.1 10. Median 1.96 -0.02 0.21 0.17 -0.01 1.6 42.5 3.93 19 9.9 Minimum 0.89 -0.02 -0.01 0.023 -0.01 -0.05 20 2.31 8.39 5.0 Maximum 3.46 0.07 2.78 0.46 0.048 5.06 66.3 4.86 27.5 15. Std. dev. 0.804 0.016 0.783 0.119 0.015 1.387 10.4 0.756 4.925 3 

N obs. 23 18 23 14 23 23 23 23 23 2

M206.1T Mean 1.86 0.07 0.34 0.15 0.033 4.35 59.9 6.34 19 9.3 Median 1.66 -0.02 -0.01 0.13 0.01 2.38 64.5 6.18 19.2 8.5 Minimum 0.43 -0.02 -0.01 0.043 -0.01 -0.05 36 2.82 10.7 5.7 Maximum 3.27 0.5 2.33 0.29 0.17 12.7 88.6 10.2 28.7 16. Std. dev. 0.838 0.135 0.747 0.076 0.045 4.607 14.54 1.898 5.294 2.73

N obs. 17 12 17 12 17 17 17 17 17 1

M235.5D Mean 2.77 0.3 0.84 0.38 0.015 2.41 44.4 4.57 13.2 6.2 Median 2.55 0.2 0.21 0.26 -0.01 2.73 43.7 4.38 12.6 5. Minimum 1.06 -0.02 -0.01 0.11 -0.01 0.86 20.2 3.3 3.6 3.6 Maximum 5.74 1.1 2.93 1.03 0.053 3.79 64.8 6.12 21.6 9.5 Std. dev. 1.231 0.355 1.083 0.298 0.017 0.985 13.02 0.774 4.63 1.95

N obs. 14 9 14 10 14 14 14 14 14 1

M237.2G Mean 3.49 0.1 2.48 0.37 0.057 3.93 44.3 4.08 16.9 10. Median 3.22 0.05 2.29 0.23 0.038 3.8 45.1 4.08 16.9 10. Minimum 1.29 -0.02 0.55 0.13 0.019 0.38 18 2.85 2.87 5.0 Maximum 6.75 0.5 4.34 1.22 0.25 6.26 61.4 5.7 25 18. Std. dev. 1.317 0.157 0.968 0.348 0.053 1.439 11.82 0.773 5.379 3.09

N obs. 17 13 18 11 18 18 18 18 18 1

M241.4K Mean 2.85 0.08 1.86 0.23 0.044 4.13 44.2 3.74 18.6 10. Median 2.82 0.04 1.84 0.22 0.034 3.62 42.3 3.66 19.1 10. Minimum 1.31 -0.02 0.23 0.097 0.01 0.14 20.2 1.71 9.13 5. Maximum 4.57 0.5 4.06 0.48 0.19 20.3 63.7 5.61 27.4 17. Std. dev. 1.024 0.142 1.007 0.097 0.04 3.943 10.6 0.902 4.363 2.88

N obs. 22 17 22 14 22 22 22 22 22 2
E-34

Table E-2. Continued.

Samplinglocation Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sodium 

1996 Near-surface measurements: 

MO02.0X Mean 2.35 0.07 1.21 0.38 0.038 4.87 52.4 6.41 16.3 42. Median 2.1 0.02 1.22 0.21 0.039 5.02 53.1 6.42 15.8 41. Minimum 0.7 -0.02 0.5 0.082 -0.01 3.41 23.4 3.69 7.69 2 Maximum 4.5 0.3 2.83 1.52 0.072 7.02 83.2 8.52 26.6 65. Std. dev. 1.013 0.084 0.482 0.423 0.018 1.058 13.69 1.08 4.591 10.8

N obs. 24 20 25 16 25 25 25 25 25 2

PE01.8M Mean 1.48 0.08 0.35 0.16 0.019 2.32 46.8 4.6 9.89 19. Median 1.31 0.05 0.27 0.092 -0.01 2.79 47.5 4.74 9.28 17. Minimum 0.8 -0.02 -0.01 0.033 -0.01 -0.05 21.5 3.03 4.83 9.5 Maximum 3.92 0.2 0.99 0.49 0.23 4.54 66.3 6.81 15.2 3 Std. dev. 0.801 0.066 0.28 0.147 0.048 1.329 12.28 1.007 3.133 7.91

N obs. 21 20 21 12 21 21 21 21 21 2

PI00.2M Mean 2.77 0.2 1.63 0.38 0.069 3.55 55.5 5.08 21.1 16. Median 2.49 0.2 1.36 0.16 0.029 3.5 53.4 4.77 20.3 16. Minimum 0.84 -0.02 0.28 0.08 -0.01 1.06 20.9 2.94 5.73 9.1 Maximum 6.82 0.7 5.73 2 0.43 5.72 97.7 9.9 38.4 2 Std. dev. 1.552 0.182 1.166 0.516 0.097 1.171 19.4 1.407 8.01 5.02

N obs. 25 20 25 16 25 25 25 25 25 2

WD00.2M Mean 4.16 0.7 2.35 0.53 0.27 4.05 59.6 6.11 23.1 33. Median 3.69 0.3 1.93 0.36 0.11 3.61 57.9 6 22 2 Minimum 1.76 -0.02 0.93 0.11 0.052 2.2 22.9 4.41 6.68 12. Maximum 7.18 2.4 5.11 1.92 1.03 6.27 88 8.31 38.4 82. Std. dev. 1.416 0.805 1.258 0.533 0.296 1.405 21.11 1.08 9.461 21.9

N obs. 14 9 14 12 14 14 14 14 14 1
E-35

Figure E-1a. Monthly means of temperature (°C), dissolved oxygen (mg/L), oxygen saturation (%), pH, specific

conductivity (:S), turbidity (NTU), and Secchi transparency (cm) at sites in upper and lower Pool 26 from 1993 through

1996.
E-36

Figure E-1b. Monthly means of temperature (°C), dissolved oxygen (mg/L), oxygen saturation (%), pH, specific

conductivity (:S), and turbidity (NTU) in the Illinois River from 1993 through 1996.
E-37

Figure E-1c. Monthly means of temperature (°C), dissolved oxygen (mg/L), oxygen saturation (%), pH, specific

conductivity (:S), and turbidity (NTU) in the Missouri River from 1993 through 1996.
E-38

Figure E-2a. Monthly means of total nitrogen (mg/L), nitrate–nitrite nitrogen (mg/L), ammonium nitrogen (mg/L), silicate

silicon (mg/L), total phosphorus (mg/L), soluble reactive phosphorus (mg/L), total suspended solids (mg/L), and

chlorophyll a (:g/L) at sites in upper and lower Pool 26 from 1993 through 1996.
E-39

Figure E-2b. Monthly means of total nitrogen (mg/L), nitrate–nitrite nitrogen (mg/L), ammonium nitrogen (mg/L), silicate

silicon (mg/L), total phosphorus (mg/L), soluble reactive phosphorus (mg/L), total suspended solids (mg/L), and

chlorophyll a (:g/L) in the Illinois River from 1993 through 1996.
E-40

Figure E-2c. Monthly means of total nitrogen (mg/L), nitrate–nitrite nitrogen (mg/L), ammonium nitrogen (mg/L), silicate

silicon (mg/L), total phosphorus (mg/L), soluble reactive phosphorus (mg/L), total suspended solids (mg/L), and

chlorophyll a (:g/L) in the Missouri River from 1993 through 1996.
F-1

Appendix F. Stratified Random Sampling Data: 1993–1996

In Appendix F, we summarize data from stratified random sampling (SRS) in both tabular and graphic

forms. The tables contain summary statistics for each SRS episode and stratum divided into two parameter

groups: (1) physical and biological measurements (Table F-1), and (2) chemical data (major plant nutrients;

Table F-2). Within each parameter group, the data are divided by sampling depth into three groups (surface,

middepth, and bottom). Chemical measurements are typically collected only at the surface and near the

bottom. The majority of all measurement are in the near-surface category and most episodes do not have

chemical data from other depths. Refer to Appendix A for maps and descriptions of the individual sampling

strata and episodes.

The figures (F-1–F-13) are box-whisker diagrams that connect the medians for each sampling episode

from spring 1993 through fall 1996. The 10th and 90th percentiles for each episode are indicated by the

lower and upper limits of the box. Vertical lines extend above and below each box to the minimum and

maximum observed value or to the limits of the plotting axis.

Data that have been flagged as questionable in the Long Term Resource Monitoring Program database

because of recorder error, instrument malfunction, sample damage, contamination, improper handling,

analytical error, or other difficulties are excluded from this summary. Values that are below detection are

indicated by the detection limit preceded by a negative sign. Below-detection values are included in the

determination of minima, maxima, and medians, but in the calculation of means and standard deviations,

values below detection have been replaced by a value equal to half the detection limit. The Secchi

transparency data in this report do not include observations where Secchi transparency exceeded the water

column depth. High transparency conditions are thus underrepresented.
F-2

Table F-1. Summaries of physical–biological measurements during each stratified random sampling episode from 1993 through 1996. Dsampling-depth categories: near–surface (less than or equal to 0.2 m below the surface), middepth, and near–bottom (less than or equal to 

Samplingstratum Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

s

1993 Near-surface measurements: fall

1. Main channel Mean 0.2 6.1 0.57 — — — — 14.3 9.53 93 493 8.5 26.7 67  Median 0.2 4.9 0.58 — — — — 14 9.4 92 480 8.6 27 53  Minimum 0.2 1.4 0.53 — — — — 13 6.5 68 433 7.5 20 30  Maximum 0.2 11.9 0.6 — — — — 17.5 12.3 117 560 9 40 290  Std. dev. 0 3.47 0.04 — — — — 1.05 1.65 14.9 43.3 0.39 4.66 55 

N obs. 20 20 4 0 0 0 0 20 20 20 20 16 20 20 

2. Side channel Mean 0.2 3.37 0.48 — — — — 13.5 10.3 98 480 8.5 29 52  Median 0.2 2.7 0.47 — — — — 13.6 10.6 103 466 8.6 29 41  Minimum 0.2 0.6 0 — — — — 7.4 5 50 417 7.4 17 25  Maximum 0.2 9 0.95 — — — — 16 13.5 128 563 9 44 200  Std. dev. 0 2.27 0.21 — — — — 1.3 1.95 17.8 41.4 0.44 6.53 30.2 

N obs. 41 41 41 0 0 0 0 41 41 41 41 25 41 41 

3. Backwater Mean 0.2 1.27 0.03 — — — — 15 8.63 86 493 8 27.2 48  Median 0.2 1.25 0 — — — — 15.2 8.9 88 479 8 26.5 40  Minimum 0.2 0.4 0 — — — — 10.1 3.6 36 391 7.5 9 21  Maximum 0.2 2.4 0.48 — — — — 21 17 176 661 8.9 50 175  Std. dev. 0 0.59 0.11 — — — — 2.35 3.32 34.7 73.8 0.42 8.93 33.7 

N obs. 20 20 20 0 0 0 0 20 20 20 20 18 20 20 

4. Lake Mean 0.2 0.76 0 — — — — 12.5 12.4 117 549 8.5 32.7 36  Median 0.2 0.8 0 — — — — 13.4 12.2 113 538 8.6 32 33  Minimum 0.2 0.5 0 — — — — 9.1 8.8 86 481 7.9 15 15  Maximum 0.2 1.1 0 — — — — 16 17.4 170 697 9.1 50 90  Std. dev. 0 0.21 0 — — — — 2.36 2.42 24.4 49 0.39 9.97 19.5 

N obs. 15 15 15 0 0 0 0 15 15 15 15 15 15 15 

5. Impounded Mean 0.2 1.73 0.02 — — — — 15.4 9.07 91 436 8.2 30.1 36  Median 0.2 1.2 0 — — — — 15.5 8.5 86 435 8.3 30 37  Minimum 0.2 0.5 0 — — — — 14.8 8.2 82 418 8 24 21  Maximum 0.2 4.1 0.15 — — — — 15.9 10.3 104 461 8.4 37 45  Std. dev. 0 1.12 0.06 — — — — 0.36 0.82 8.47 12.4 0.12 3.91 6.76 

N obs. 15 15 7 0 0 0 0 15 15 15 15 15 15 15 
F-3

Table F-1. Continued.

Samplingstratum Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Tota

suspen

solid

(mg/

1993 Near-bottom measurements: fall

1. Main channel Mean 1.6 1.8 — — — — — 13.8 11.8 114 — — — — —  Median 1.6 1.8 — — — — — 13.8 11.8 114 — — — — —  Minimum 1.6 1.8 — — — — — 13.8 11.8 114 — — — — —  Maximum 1.6 1.8 — — — — — 13.8 11.8 114 — — — — —  Std. dev. — — — — — — — — — — — — — — — 

N obs. 1 1 0 — — — — 1 1 1 0 0 — 0 0 

2. Side channel Mean 2.48 2.68 — — — — — 13.7 10.1 97 — — — — —  Median 1.9 2.1 — — — — — 13.7 10.6 101 — — — — —  Minimum 0.9 1.1 — — — — — 12.2 4.8 48 — — — — —  Maximum 7.4 7.6 — — — — — 16 12.3 116 — — — — —  Std. dev. 1.58 1.58 — — — — — 0.78 1.96 18 — — — — — 

N obs. 28 28 0 — — — — 28 28 28 0 0 — 0 0 

3. Backwater Mean 1.37 1.57 — — — — — 14.3 7.02 69 477 — — — —  Median 1.45 1.65 — — — — — 14.5 7.45 74 477 — — — —  Minimum 0.8 1 — — — — — 10.1 2.6 26 477 — — — —  Maximum 2.2 2.4 — — — — — 19.5 12 122 477 — — — —  Std. dev. 0.41 0.41 — — — — — 2.47 3.18 31.8 — — — — — 

N obs. 14 14 0 — — — — 14 14 14 1 0 — 0 0 

4. Lake Mean 0.87 1.07 — — — — — 12.5 13.5 127 — — — — —  Median 0.9 1.1 — — — — — 13.8 13.6 122 — — — — —  Minimum 0.8 1 — — — — — 9.9 12.6 120 — — — — —  Maximum 0.9 1.1 — — — — — 13.9 14.4 139 — — — — —  Std. dev. 0.06 0.06 — — — — — 2.28 0.9 10.5 — — — — — 

N obs. 3 3 0 — — — — 3 3 3 0 0 — 0 0 

5. Impounded Mean 1.9 2.1 — — — — — 15.2 9.13 91 — — — — —  Median 1.3 1.5 — — — — — 15.2 9 89 — — — — —  Minimum 0.8 1 — — — — — 14.5 8.2 82 — — — — —  Maximum 3.9 4.1 — — — — — 15.8 10.2 103 — — — — —  Std. dev. 1.09 1.09 — — — — — 0.39 0.73 7.29 — — — — — 

N obs. 11 11 0 — — — — 11 11 11 0 0 — 0 0 
F-4

Table F-1. Continued.

Samplingstratum Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Tota

suspen

solid

(mg/

1994 Near-surface measurements: winter

1. Main channel Mean 0.2 5.83 0.35 31.6 4 0 0 0.36 14.9 103 725 7.9 107 12 11.5  Median 0.2 6.1 0.35 40 2 0 0 0.25 14.5 100 671 7.9 125 6 5.1  Minimum 0.2 1.8 0.35 1 1 0 0 0 13.6 93 432 7.5 30 4 3.5  Maximum 0.2 9.8 0.35 85 18 0 0 1 16.6 114 1104 8.7 170 41 40.2  Std. dev. 0 2.26 — 27.4 4.4 0 0 0.32 0.93 6.65 173 0.33 45 11.2 11.9 

N obs. 18 18 1 15 15 15 15 18 18 18 18 13 17 17 17 

2. Side channel Mean 0.2 4.13 0.31 42.6 8 5 0 0.29 13.9 96 714 8 118 10 9.4  Median 0.2 3.4 0.28 20 7 0 0 0.2 14 96 705 8.1 128 7 5.1  Minimum 0.2 0.7 0.04 1 1 0 0 0 12.3 85 525 7.2 35 3 3.3  Maximum 0.2 10.1 0.6 100 18 50 1 1.2 16.4 113 999 8.6 200 35 52  Std. dev. 0 2.36 0.16 41.8 5.8 13 .45 0.33 1.21 8.81 133 0.33 49.6 8.44 10.3 

N obs. 29 29 29 19 19 19 19 29 29 29 29 24 20 29 29 

3. Backwater Mean 0.2 0.89 0 95 13 0 0 4.02 14.4 108 564 8.2 45.3 26 33.8  Median 0.2 0.8 0 100 12 0 0 4.2 13.7 99 558 8.3 39 26 33.9  Minimum 0.2 0.5 0 60 7 0 0 0.2 7.2 55 448 7.6 20 7 6.4  Maximum 0.2 2 0 100 20 0 0 8 20 163 640 8.6 110 46 60.8  Std. dev. 0 0.44 0 14.1 4.34 0 0 2.49 5.29 39.5 61.1 0.51 28.2 14.5 16.3 

N obs. 11 11 9 8 8 8 8 11 10 10 11 3 8 11 11 

4. Lake Mean 0.2 0.38 0.05 67.3 11 57 1 2.17 19.9 145 496 — 25 29 38.2  Median 0.2 0.4 0.05 100 15 85 2 3 20 147 473 — 25 24 37.2  Minimum 0.2 0.3 0.04 2 2 0 0 0.5 19.8 139 470 — 25 15 21.6  Maximum 0.2 0.5 0.06 100 15 85 2 3 20 149 544 — 25 49 55.7  Std. dev. 0 0.08 0.01 56.6 7.51 49.1 1.2 1.44 0.12 5.36 41.9 — — 17.6 17.1 

N obs. 5 5 3 3 3 3 3 3 3 3 3 0 1 3 3 

5. Impounded Mean 0.2 3 — 98.8 20 88 1 0.68 13.4 93 556 — 104 9 9.6  Median 0.2 3 — 100 21 100 1 0.65 13.5 93 619 — 120 7 7.2  Minimum 0.2 1 — 90 12 1 1 0.2 12 84 323 — 50 5 5.6  Maximum 0.2 4.7 — 100 28 100 1 1 14.7 101 679 — 140 15 17.8  Std. dev. 0 1.32 — 3.54 5.99 35 0 0.28 0.93 6.09 134 — 35.4 3.66 4.68 

N obs. 8 8 0 8 8 8 7 8 8 8 8 0 7 8 8 
F-5

Table F-1. Continued.

Samplingstratum Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Tota

suspen

solid

(mg/

1994 Near-bottom measurements: winter

2. Side channel Mean 3.57 3.77 — — — — — 0.56 14.7 102 — — — — —  Median 2.8 3 — — — — — 0.4 14.8 102 — — — — —  Minimum 1.8 2 — — — — — 0.1 14 96 — — — — —  Maximum 6.2 6.4 — — — — — 1.3 15.5 110 — — — — —  Std. dev. 1.82 1.82 — — — — — 0.5 0.56 5.26 — — — — — 

N obs. 7 7 0 — — — — 7 7 7 0 0 — 0 0 

3. Backwater Mean 1 1.2 — — — — — 4.25 10.2 78 — — — — —  Median 1 1.2 — — — — — 4.25 10.2 78 — — — — —  Minimum 0.9 1.1 — — — — — 3.5 9 70 — — — — —  Maximum 1.1 1.3 — — — — — 5 11.4 86 — — — — —  Std. dev. 0.14 0.14 — — — — — 1.06 1.7 10.9 — — — — — 

N obs. 2 2 0 — — — — 2 2 2 0 0 — 0 0 

5. Impounded Mean 3.09 3.29 — — — — — 0.76 13 91 — — — — —  Median 3.1 3.3 — — — — — 0.7 12.8 90 — — — — —  Minimum 1.7 1.9 — — — — — 0.5 12.2 86 — — — — —  Maximum 4.5 4.7 — — — — — 1 13.8 96 — — — — —  Std. dev. 1.13 1.13 — — — — — 0.24 0.59 3.84 — — — — — 

N obs. 7 7 0 — — — — 7 7 7 0 0 — 0 0 

1994 Near-surface measurements: spring

1. Main channel Mean 0.2 6.08 1.3 — — — — 16.1 8.54 87 389 8.7 19.1 83 142  Median 0.2 6.2 1.3 — — — — 16.2 8.3 83 374 8.6 21 73 127  Minimum 0.2 0.8 1.02 — — — — 13.7 7 71 332 8.2 8 47 51.3  Maximum 0.2 11.4 1.58 — — — — 18.2 10.7 113 517 9.2 32 150 288  Std. dev. 0 2.71 0.4 — — — — 1.38 0.98 11.4 49.2 0.34 7.31 30.3 73.6 

N obs. 20 20 2 0 0 0 0 20 20 20 20 11 20 20 20 

2. Side channel Mean 0.2 3.85 0.67 — — — — 15.3 8.36 84 386 8.7 17.7 91 126  Median 0.2 3.1 0.68 — — — — 15 8.3 82 374 8.6 18 77 113  Minimum 0.2 0.97 0 — — — — 6.5 7.2 71 227 8.2 6 48 43.9  Maximum 0.2 8.7 1.11 — — — — 18.5 10.8 114 539 9.2 45 280 308  Std. dev. 0 2.23 0.27 — — — — 2.01 0.96 11.3 67.1 0.35 7.62 46.7 69.5 

N obs. 42 42 40 0 0 0 0 42 42 42 42 15 42 42 42 
F-6

Table F-1. Continued.

Samplingstratum Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice 

(cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Tota

suspen

solid

(mg/

1994 Near-surface measurements: spring

3. Backwater Mean 0.2 1.13 0.01 — — — — 16.9 9.24 96 333 8.6 20 83 68.9  Median 0.2 1.02 0 — — — — 16.6 9 94 329 8.3 19 66 57.9  Minimum 0.2 0.4 0 — — — — 12.6 5.6 57 238 8 5 22 27.3  Maximum 0.2 2.8 0.16 — — — — 23.1 13.4 151 488 9.3 41 360 167  Std. dev. 0 0.49 0.03 — — — — 3.19 2.06 24.8 56.4 0.56 9.02 66.9 35.4 

N obs. 28 28 28 0 0 0 0 28 28 28 28 5 28 28 28 

4. Lake Mean 0.2 1.44 0 — — — — 19.7 11.2 122 488 8.5 23.7 48 47.5  Median 0.2 1.5 0 — — — — 21.1 10.3 114 468 8.6 22 51 51  Minimum 0.2 0.87 0 — — — — 15.7 7.4 83 452 8.1 14 20 18.3  Maximum 0.2 2 0.02 — — — — 24.2 19.6 207 547 8.7 33 91 94.8  Std. dev. 0 0.37 0.01 — — — — 3.09 3.03 31 33.4 0.2 6.88 21.9 22.6 

N obs. 15 15 15 0 0 0 0 15 15 15 15 8 15 15 15 

5. Impounded Mean 0.2 1.92 0 — — — — 15 8.42 83 324 8.5 17.8 84 79.8  Median 0.2 1.6 0 — — — — 14.5 8.1 80 324 8.1 17 64 72.1  Minimum 0.2 0.9 0 — — — — 12.2 7.6 76 308 8.1 12 44 38.4  Maximum 0.2 5.1 0 — — — — 18.5 11.1 103 336 9.2 28 200 149  Std. dev. 0 1.01 0 — — — — 1.79 0.86 7.4 8.59 0.64 4.35 47.2 33.8 

N obs. 15 15 14 0 0 0 0 15 15 15 15 3 15 15 15 

1994 Middepth measurements: spring

3. Backwater Mean 0.8 1.09 — — — — — 13.4 5.9 57 — — — — —  Median 0.8 1.09 — — — — — 13.4 5.9 57 — — — — —  Minimum 0.8 1.09 — — — — — 13.4 5.9 57 — — — — —  Maximum 0.8 1.09 — — — — — 13.4 5.9 57 — — — — —  Std. dev. — — — — — — — — — — — — — — — 

N obs. 1 1 0 — — — — 1 1 1 0 0 — 0 0 

4. Lake Mean 0.8 1.09 — — — — — 23 10.3 121 — — — — —  Median 0.8 1.09 — — — — — 23 10.3 121 — — — — —  Minimum 0.8 1.09 — — — — — 23 10.3 121 — — — — —  Maximum 0.8 1.09 — — — — — 23 10.3 121 — — — — —  Std. dev. — — — — — — — — — — — — — — — 

N obs. 1 1 0 — — — — 1 1 1 0 0 — 0 0 
F-7

Table F-1. Continued.

Samplingstratum Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Tota

suspen

solid

(mg/

1994 Near-bottom measurements: spring

2. Side channel Mean 2.5 2.71 — — — — — 15.6 8.52 86 — — — — —  Median 2.4 2.6 — — — — — 15 8.4 83 — — — — —  Minimum 0.8 1.03 — — — — — 12.9 7.1 70 — — — — —  Maximum 6.2 6.4 — — — — — 18.5 10.8 114 — — — — —  Std. dev. 1.14 1.13 — — — — — 1.52 1.05 12.3 — — — — — 

N obs. 27 27 0 — — — — 27 27 27 0 0 — 0 0 

3. Backwater Mean 1.21 1.43 — — — — — 16.7 8.62 89 — — — — —  Median 1 1.24 — — — — — 16.5 8.85 87 — — — — —  Minimum 0.8 1.01 — — — — — 12.9 5.8 61 — — — — —  Maximum 2.6 2.8 — — — — — 23 11.7 128 — — — — —  Std. dev. 0.53 0.51 — — — — — 3.18 2.02 21.8 — — — — — 

N obs. 14 14 0 — — — — 14 14 14 0 0 — 0 0 

4. Lake Mean 1.35 1.56 — — — — — 17.7 9.2 97 522 — — — 50.1  Median 1.5 1.7 — — — — — 15.2 8.6 92 522 — — — 50.1  Minimum 0.8 1.05 — — — — — 14.2 7.7 80 489 — — — 42.8  Maximum 1.8 2 — — — — — 22.6 14.7 147 554 — — — 57.3  Std. dev. 0.32 0.31 — — — — — 3.56 1.84 19 46 — — — 10.3 

N obs. 12 12 0 — — — — 12 12 12 2 0 — 0 2 

5. Impounded Mean 1.9 2.11 — — — — — 14.3 8.34 81 — — — — —  Median 1.65 1.85 — — — — — 14.2 8.2 80 — — — — —  Minimum 0.9 1.18 — — — — — 12.1 7.6 74 — — — — —  Maximum 4.9 5.1 — — — — — 17.8 11.2 104 — — — — —  Std. dev. 1.04 1.04 — — — — — 1.3 0.96 7.97 — — — — — 

N obs. 12 12 0 — — — — 12 12 12 0 0 — 0 0 

1994 Near-surface measurements: summer

1. Main channel Mean 0.2 5.36 0.25 — — — — 26.6 7.41 93 417 8.5 40.6 30 36.8  Median 0.2 5.15 0.25 — — — — 26.6 7.6 95 419 8.5 40 27 32.2  Minimum 0.2 1.5 0 — — — — 25.8 6.1 76 309 8.2 23 21 14.9  Maximum 0.2 8 0.5 — — — — 28 9.1 116 548 8.7 58 50 69.1  Std. dev. 0 1.54 0.35 — — — — 0.65 0.88 11.4 53 0.14 9.87 9.45 16.9 

N obs. 20 20 2 0 0 0 0 20 20 20 20 20 20 18 18 
F-8

Table F-1. Continued.

Samplingstratum Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Tota

suspen

solid

(mg/

1994 Near-surface measurements: summer

2. Side channel Mean 0.2 2.99 0.44 — — — — 26.7 7.61 96 409 8.5 34.6 35 44.1  Median 0.2 2.4 0.45 — — — — 26.6 7.6 95 423 8.6 33 36 42.8  Minimum 0.2 0.61 0 — — — — 25.1 5.4 70 293 7.6 19 13 19.8  Maximum 0.2 6.7 0.88 — — — — 28.9 14.8 190 498 9.3 54 60 85.4  Std. dev. 0 1.74 0.2 — — — — 0.71 1.37 17.5 49.8 0.23 7.63 10.8 17.2 

N obs. 41 41 39 0 0 0 0 40 40 40 41 41 41 41 39 

3. Backwater Mean 0.2 0.88 0.01 — — — — 26.6 9.88 125 379 8.9 21.3 76 91.4  Median 0.2 0.75 0 — — — — 26.7 9.6 121 395 8.9 21 58 71.7  Minimum 0.2 0.34 0 — — — — 23 5 63 279 7.9 10 19 26.8  Maximum 0.2 3.4 0.38 — — — — 31.2 15 198 498 9.4 44 200 236  Std. dev. 0 0.62 0.07 — — — — 2.07 2.98 39.1 64 0.38 8.05 47.6 58.8 

N obs. 31 31 30 0 0 0 0 31 31 31 30 31 31 30 30 

5. Impounded Mean 0.2 2.07 0 — — — — 26.6 8.31 105 427 8.6 29.6 42 41.7  Median 0.2 1.65 0 — — — — 26.9 8.75 111 422 8.6 29 40 38.2  Minimum 0.2 0.79 0 — — — — 25.4 4.9 62 361 8.4 20 30 22.9  Maximum 0.2 3.9 0 — — — — 27.5 12.8 162 469 9.1 47 54 57.6  Std. dev. 0 1.01 0 — — — — 0.67 3.03 39.1 34 0.23 7.31 9.33 10.6 

N obs. 14 14 14 0 0 0 0 14 14 14 14 14 14 9 14 

1994 Middepth measurements: summer

3. Backwater Mean 0.8 1.09 — — — — — 29 14 185 — — — — —  Median 0.8 1.09 — — — — — 29 14 185 — — — — —  Minimum 0.8 1.09 — — — — — 29 14 185 — — — — —  Maximum 0.8 1.09 — — — — — 29 14 185 — — — — —  Std. dev. — — — — — — — — — — — — — — — 

N obs. 1 1 0 — — — — 1 1 1 0 0 — 0 0 

1994 Near-bottom measurements: summer

1. Main channel Mean 3.4 3.6 — — — — — 27 7 89 — — — — —  Median 3.4 3.6 — — — — — 27 7 89 — — — — —  Minimum 1.3 1.5 — — — — — 27 6.3 80 — — — — —  Maximum 5.5 5.7 — — — — — 27 7.7 98 — — — — —  Std. dev. 2.97 2.97 — — — — — 0 0.99 12.6 — — — — — 

N obs. 2 2 0 — — — — 2 2 2 0 0 — 0 0 
F-9

Table F-1. Continued.

Samplingstratum Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Tota

suspen

solid

(mg/

1994 Near-bottom measurements: summer

2. Side channel Mean 2.5 2.71 — — — — — 26.6 7.35 93 — — — — —  Median 1.9 2.1 — — — — — 26.7 7.4 91 — — — — —  Minimum 0.9 1.15 — — — — — 25 5.3 68 — — — — —  Maximum 6.5 6.7 — — — — — 27.7 13 165 — — — — —  Std. dev. 1.58 1.57 — — — — — 0.62 1.35 17 — — — — — 

N obs. 28 28 0 — — — — 28 28 28 0 0 — 0 0 

3. Backwater Mean 1.5 1.7 — — — — — 27.1 7.59 96 — — — — —  Median 1.3 1.5 — — — — — 26.8 8.4 107 — — — — —  Minimum 0.8 1 — — — — — 24.1 4.2 53 — — — — —  Maximum 3.2 3.4 — — — — — 31.2 9.8 124 — — — — —  Std. dev. 0.81 0.81 — — — — — 2.18 2.14 27.2 — — — — — 

N obs. 7 7 0 — — — — 7 7 7 0 0 — 0 0 

5. Impounded Mean 1.95 2.17 — — — — — 26.3 6.53 82 — — — — —  Median 1.4 1.65 — — — — — 26.1 6.2 77 — — — — —  Minimum 0.9 1.12 — — — — — 25.7 4.8 59 — — — — —  Maximum 3.7 3.9 — — — — — 27.1 10.4 130 — — — — —  Std. dev. 1 0.98 — — — — — 0.45 1.8 22.8 — — — — — 

N obs. 13 13 0 — — — — 13 13 13 0 0 — 0 0 

1994 Near-surface measurements: fall

1. Main channel Mean 0.2 5.9 — — — — — 16.4 9.38 96 423 8.1 41.3 27 30.7  Median 0.2 5.2 — — — — — 16.4 9.45 96 409 8.1 40 26 29.3  Minimum 0.2 2.1 — — — — — 15.7 8.4 86 397 7.9 33 18 19.7  Maximum 0.2 16 — — — — — 17.5 10.3 106 500 8.4 71 39 48.4  Std. dev. 0 2.72 — — — — — 0.48 0.53 5.3 32.8 0.13 7.97 5.03 8.2 

N obs. 20 20 0 0 0 0 0 20 20 20 20 20 20 20 20 

2. Side channel Mean 0.2 3.46 0.4 — — — — 16.5 9.2 94 425 8.1 39.2 25 30.8  Median 0.2 3 0.35 — — — — 16.4 9.3 95 410 8 39 24 29  Minimum 0.2 0.5 0 — — — — 15.8 8.3 85 398 7.5 23 19 14.4  Maximum 0.2 9.8 0.78 — — — — 18 10.1 102 517 8.9 53 36 52.8  Std. dev. 0 2.08 0.2 — — — — 0.56 0.45 4.45 33 0.19 6.48 3.89 8.74 

N obs. 42 42 38 0 0 0 0 42 42 42 42 42 42 42 42 
F-10

Table F-1. Continued.

Samplingstratum Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Tota

suspen

solid

(mg/

1994 Near-surface measurements: fall

3. Backwater Mean 0.2 0.75 0.01 — — — — 18.3 9.51 102 426 8.3 22.3 52 67.8  Median 0.2 0.62 0 — — — — 18.3 9.4 100 419 8.3 22 45 64.8  Minimum 0.2 0.33 0 — — — — 14.6 4.4 47 370 7.6 11 27 28.3  Maximum 0.2 1.8 0.3 — — — — 25.5 17 188 521 9 44 110 142  Std. dev. 0 0.42 0.06 — — — — 2.07 2.57 29 41.3 0.39 7.52 20.3 29.9 

N obs. 29 29 29 0 0 0 0 29 29 29 29 27 29 28 29 

4. Lake Mean 0.2 0.59 0 — — — — 17.2 8.07 84 613 8.3 16 78 77.4  Median 0.2 0.62 0 — — — — 18.1 8.7 90 610 8.3 16 73 75.8  Minimum 0.2 0.34 0 — — — — 15 4.4 47 575 7.9 6 34 37.1  Maximum 0.2 0.96 0 — — — — 19.4 9.9 105 674 8.7 25 140 135  Std. dev. 0 0.18 0 — — — — 1.67 1.74 18.6 29.8 0.29 6.11 29.4 26.2 

N obs. 15 15 15 0 0 0 0 15 15 15 15 15 15 15 15 

5. Impounded Mean 0.2 2.04 0.03 — — — — 17.1 10.3 107 382 8.3 31.3 29 32.6  Median 0.2 1.55 0 — — — — 17 9.8 100 381 8.1 31 25 26.3  Minimum 0.2 0.75 0 — — — — 16.3 7.7 81 367 7.8 20 20 20.5  Maximum 0.2 5.1 0.17 — — — — 18.4 17.7 183 397 9.1 45 53 68.4  Std. dev. 0 1.4 0.06 — — — — 0.73 2.56 26.5 8.29 0.34 6.67 9.68 13.1 

N obs. 15 15 15 0 0 0 0 15 15 15 15 15 15 15 15 

1994 Middepth measurements: fall

2. Side channel Mean 2.1 3.3 — — — — — 17.1 9 93 — — — — —  Median 2.1 3.3 — — — — — 17.1 9 93 — — — — —  Minimum 2.1 3.3 — — — — — 17.1 9 93 — — — — —  Maximum 2.1 3.3 — — — — — 17.1 9 93 — — — — —  Std. dev. — — — — — — — — — — — — — — — 

N obs. 1 1 0 — — — — 1 1 1 0 0 — 0 0 

5. Impounded Mean 2.7 3.9 — — — — — 16.7 10.5 108 — — — — —  Median 2.7 3.9 — — — — — 16.7 10.5 108 — — — — —  Minimum 2.7 3.9 — — — — — 16.7 10.5 108 — — — — —  Maximum 2.7 3.9 — — — — — 16.7 10.5 108 — — — — —  Std. dev. — — — — — — — — — — — — — — — 

N obs. 1 1 0 — — — — 1 1 1 0 0 — 0 0 
F-11

Table F-1. Continued.

Samplingstratum Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Tota

suspen

solid

(mg/

1994 Near-bottom measurements: fall

1. Main channel Mean 1.8 2.1 — — — — — 16.4 8.6 88 — — — — —  Median 1.8 2.1 — — — — — 16.4 8.6 88 — — — — —  Minimum 1.8 2.1 — — — — — 16.4 8.6 88 — — — — —  Maximum 1.8 2.1 — — — — — 16.4 8.6 88 — — — — —  Std. dev. — — — — — — — — — — — — — — — 

N obs. 1 1 0 — — — — 1 1 1 0 0 — 0 0 

2. Side channel Mean 1.85 2.06 — — — — — 16.4 9.11 93 410 8 — — —  Median 1.6 1.8 — — — — — 16.3 9.3 94 410 8 — — —  Minimum 1 1.2 — — — — — 15.8 7.9 82 410 8 — — —  Maximum 4.3 4.5 — — — — — 17.4 9.7 100 410 8 — — —  Std. dev. 0.94 0.94 — — — — — 0.52 0.5 4.83 — — — — — 

N obs. 15 15 0 — — — — 15 15 15 1 1 — 0 0 

3. Backwater Mean 1.43 1.63 — — — — — 19.5 6.63 73 — — — — —  Median 1.45 1.65 — — — — — 17.8 6.8 71 — — — — —  Minimum 1.2 1.4 — — — — — 16.8 3.9 41 — — — — —  Maximum 1.6 1.8 — — — — — 25.5 9 111 — — — — —  Std. dev. 0.21 0.21 — — — — — 4.05 2.09 28.6 — — — — — 

N obs. 4 4 0 — — — — 4 4 4 0 0 — 0 0 

5. Impounded Mean 2.11 2.32 — — — — — 16.8 8.6 89 — — — — —  Median 1.65 1.85 — — — — — 16.8 9.5 97 — — — — —  Minimum 0.9 1.1 — — — — — 16.2 1.4 15 — — — — —  Maximum 4.9 5.1 — — — — — 18.2 10.9 112 — — — — —  Std. dev. 1.41 1.41 — — — — — 0.65 2.73 28.1 — — — — — 

N obs. 10 10 0 — — — — 10 10 10 0 0 — 0 0 

1995 Near-surface measurements: winter

1. Main channel Mean 0.2 5.88 — 40.6 2 0 0 0.52 14 97 525 8 51.8 33 40.4  Median 0.2 5.7 — 35 1 0 0 0.4 14 97 507 8 47 27 29  Minimum 0.2 1.5 — 5 1 0 0 0 12.6 88 304 7.8 19 15 10  Maximum 0.2 12 — 80 4 0 0 1.3 16.6 117 695 8.2 86 88 98.2  Std. dev. 0 3.03 — 30.7 1 0 0 0.44 0.89 6.39 98.2 0.12 22.3 20.2 28.8 

N obs. 20 20 0 9 9 9 9 20 20 20 20 9 20 20 20 
F-12

Table F-1. Continued.

Samplingstratum Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Tota

suspen

solid

(mg/

1995 Near-surface measurements: winter

2. Side channel Mean 0.2 4.03 0.34 23.9 2 0 0 0.95 14.1 99 475 8.1 41.6 68 62.9  Median 0.2 4 0.35 12.5 2 0 0 0.5 13.8 96 505 8 35 35 42.9  Minimum 0.2 0.88 0 1 1 0 0 0 12.2 84 189 7.5 10 12 8.7  Maximum 0.2 10 0.65 100 6 0 0 4.4 20 154 732 9.2 85 270 254  Std. dev. 0 2.27 0.15 31.3 1.62 0 0 1.15 1.84 16.3 140 0.45 21.4 74.5 60.9 

N obs. 41 41 41 28 28 28 28 41 41 41 41 22 41 41 40 

3. Backwater Mean 0.2 0.8 0 83.5 4 19 0 3.18 15.2 114 406 8.7 35.7 36 31.6  Median 0.2 0.66 0 95 4 0 0 3.2 14.6 114 392 9 28 26 28.3  Minimum 0.2 0.3 0 5 1 0 0 0.9 9.2 66 331 7.9 18 8 8.5  Maximum 0.2 1.8 0.08 100 15 95 2 5 20 152 644 9.2 80 83 76.9  Std. dev. 0 0.43 0.02 27.8 3.32 34.9 .61 1.21 3.32 25.2 70.6 0.44 16.2 20.8 17.7 

N obs. 23 23 23 17 17 17 17 23 23 23 23 9 17 23 23 

5. Impounded Mean 0.2 2.02 0 97.9 7 0 0 1.34 14.2 101 472 8.4 50.8 29 21  Median 0.2 1.9 0 100 7 0 0 1.1 14 101 483 8.4 55 21 17.8  Minimum 0.2 0.45 0 80 3 0 0 0.6 9.2 66 433 8.2 23 8 6.3  Maximum 0.2 4.8 0 100 10 0 0 2.3 16.1 113 507 8.8 70 58 50.8  Std. dev. 0 1.33 0 5.79 1.95 0 0 0.5 1.55 10.9 26.8 0.16 20.2 17.5 14.5 

N obs. 15 15 15 14 14 14 14 15 15 15 15 13 4 15 15 

1995 Near-bottom measurements: winter

2. Side channel Mean 3.3 3.52 — — — — — 1.15 13.6 96 — — — — —  Median 3.25 3.45 — — — — — 1.05 13.6 95 — — — — —  Minimum 0.9 1.18 — — — — — 1 12.5 89 — — — — —  Maximum 5.8 6 — — — — — 1.5 14.9 105 — — — — —  Std. dev. 2.09 2.06 — — — — — 0.24 1.08 7.13 — — — — — 

N obs. 4 4 0 — — — — 4 4 4 0 0 — 0 0 

3. Backwater Mean 1.13 1.34 — — — — — 3.73 15 114 — — — — —  Median 1 1.23 — — — — — 4.4 15.1 118 — — — — —  Minimum 0.9 1.1 — — — — — 1.2 13.9 98 — — — — —  Maximum 1.6 1.8 — — — — — 4.9 16 122 — — — — —  Std. dev. 0.33 0.32 — — — — — 1.73 0.95 11.2 — — — — — 

N obs. 4 4 0 — — — — 4 4 4 0 0 — 0 0 
F-13

Table F-1. Continued.

Samplingstratum Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Tota

suspen

solid

(mg/

1995 Near-bottom measurements: winter

5. Impounded Mean 2.32 2.52 — — — — — 1.52 14.1 101 486 8.3 — — —  Median 1.9 2.1 — — — — — 1.6 14 101 486 8.3 — — —  Minimum 0.8 1 — — — — — 0.5 12.6 91 471 8.2 — — —  Maximum 4.6 4.8 — — — — — 2.1 15.3 108 501 8.3 — — —  Std. dev. 1.2 1.2 — — — — — 0.49 0.75 5.17 21.2 0.07 — — — 

N obs. 11 11 0 — — — — 11 11 11 2 2 — 0 0 

1995 Near-surface measurements: spring

1. Main channel Mean 0.2 6.77 0.68 — — — — 11.7 10.1 93 498 7.9 20.7 90 152  Median 0.2 6.6 0.6 — — — — 11.9 10.2 94 492 7.9 19.5 86 157  Minimum 0.2 0.51 0.55 — — — — 10.7 9.1 85 445 7.8 14 51 89.1  Maximum 0.2 14.1 0.88 — — — — 12.6 10.9 99 598 8.1 29 200 218  Std. dev. 0 3.66 0.18 — — — — 0.48 0.47 3.76 37.4 0.08 4.33 31.4 36.1 

N obs. 20 20 3 0 0 0 0 20 20 20 20 19 20 20 20 

2. Side channel Mean 0.2 3.91 0.82 — — — — 11.8 10 93 505 7.9 21.1 86 144  Median 0.2 4.3 0.85 — — — — 11.7 10.1 93 490 7.9 22 82 141  Minimum 0.2 0.55 0 — — — — 11 8.8 83 439 7.7 14 61 76.2  Maximum 0.2 8.2 1.16 — — — — 13 10.8 99 630 8.1 28 160 238  Std. dev. 0 2.1 0.25 — — — — 0.41 0.48 3.91 45.7 0.13 2.95 25.3 36.1 

N obs. 41 41 41 0 0 0 0 41 41 41 41 37 41 41 41 

3. Backwater Mean 0.2 1.23 0.04 — — — — 14.9 11.3 112 448 7.9 32.9 50 68.4  Median 0.2 1.15 0 — — — — 14.9 10.3 98 431 7.9 35 27 39.4  Minimum 0.2 0.3 0 — — — — 11.6 5.4 57 343 7.6 10 12 11.5  Maximum 0.2 3 0.61 — — — — 20.1 20 209 666 8.2 58 160 189  Std. dev. 0 0.67 0.15 — — — — 2.07 3.71 39.3 73.6 0.17 13.7 43.5 56.1 

N obs. 30 30 30 0 0 0 0 30 30 30 30 9 29 30 30 

4. Lake Mean 0.2 1.74 0 — — — — 14.5 15.3 150 540 8.6 31.3 33 36.2  Median 0.2 1.5 0 — — — — 14.4 15.5 152 515 8.7 28 33 39.8  Minimum 0.2 1.1 0 — — — — 13.2 11.1 109 495 8 22 17 18  Maximum 0.2 3.1 0 — — — — 15.5 18.4 179 658 8.9 47 48 53  Std. dev. 0 0.69 0 — — — — 0.57 2.24 22.4 52.1 0.34 8.05 7.99 10.1 

N obs. 15 15 7 0 0 0 0 15 15 15 15 7 15 15 15 
F-14

Table F-1. Continued.

Samplingstratum Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Tota

suspen

solid

(mg/

1995 Near-surface measurements: spring

5. Impounded Mean 0.2 1.93 0.05 — — — — 13.8 11 107 418 8.5 28.5 64 75.4  Median 0.2 1.7 0 — — — — 13.6 10.3 100 418 8.4 31 60 57.2  Minimum 0.2 0.44 0 — — — — 12 9.6 91 394 8.3 14 22 22.1  Maximum 0.2 4.3 0.2 — — — — 15.4 14.5 145 441 8.7 44 130 215  Std. dev. 0 1.12 0.07 — — — — 0.97 1.58 17.2 15.6 0.16 8.98 30 57.7 

N obs. 15 15 13 0 0 0 0 15 15 15 15 8 15 15 15 

1995 Near-bottom measurements: spring

2. Side channel Mean 3.8 4 — — — — — 11.7 10.2 93 503 8 — — —  Median 3.8 4 — — — — — 11.7 10.2 93 503 8 — — —  Minimum 3.5 3.7 — — — — — 11.4 10.1 93 496 7.9 — — —  Maximum 4.1 4.3 — — — — — 11.9 10.2 94 510 8 — — —  Std. dev. 0.42 0.42 — — — — — 0.35 0.07 0.11 9.9 0.07 — — — 

N obs. 2 2 0 — — — — 2 2 2 2 2 — 0 0 

3. Backwater Mean 1.36 1.57 — — — — — 14.2 10.8 106 477 7.9 — — —  Median 1.2 1.5 — — — — — 13.5 10 93 463 8 — — —  Minimum 0.8 1.03 — — — — — 11.6 5.6 52 382 7.4 — — —  Maximum 2.2 2.4 — — — — — 18.9 19.8 201 643 8.2 — — —  Std. dev. 0.43 0.42 — — — — — 2.17 3.99 42.1 75.4 0.26 — — — 

N obs. 17 17 0 — — — — 17 17 17 16 8 — 0 0 

4. Lake Mean 1.59 1.74 — — — — — 13.7 13.8 133 543 8.6 — 160 147  Median 1.3 1.5 — — — — — 13.5 12.8 124 520 8.6 — 160 147  Minimum 0.9 1.1 — — — — — 12.5 9.6 92 506 8.3 — 160 147  Maximum 2.9 3.1 — — — — — 15.2 18.9 186 613 8.9 — 160 147  Std. dev. 0.73 0.69 — — — — — 0.76 2.62 27.1 38.1 0.22 — — — 

N obs. 15 15 0 — — — — 15 15 15 15 7 — 1 1 

5. Impounded Mean 2.04 2.24 — — — — — 13.2 10.7 102 418 8.4 — — —  Median 1.5 1.7 — — — — — 12.9 10.2 98 418 8.4 — — —  Minimum 0.9 1.1 — — — — — 12 9.6 90 395 8.2 — — —  Maximum 4.1 4.3 — — — — — 14.2 12.6 122 435 8.5 — — —  Std. dev. 1.1 1.1 — — — — — 0.68 1.14 11.5 14 0.12 — — — 

N obs. 11 11 0 — — — — 11 11 11 11 5 — 0 0 
F-15

Table F-1. Continued.

Samplingstratum Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Tota

suspen

solid

(mg/

1995 Near-surface measurements: summer

1. Main channel Mean 0.2 5.43 0.26 — — — — 28.9 7.89 104 524 8.2 39.2 31 37.6  Median 0.2 4.9 0.26 — — — — 28.8 8 106 514 8.2 41 31 37.1  Minimum 0.2 1.2 0 — — — — 28 6.3 82 472 7.9 26 21 22.1  Maximum 0.2 12.2 0.52 — — — — 31.5 9.8 135 603 8.5 50 47 57.5  Std. dev. 0 2.81 0.37 — — — — 0.81 0.83 12.4 33.4 0.14 6.68 7.06 10.9 

N obs. 21 21 2 0 0 0 0 21 21 21 18 21 21 21 21 

2. Side channel Mean 0.2 3.68 0.48 — — — — 29 7.99 106 514 8.2 37 32 43.4  Median 0.2 3.4 0.48 — — — — 28.9 7.8 103 502 8.2 37.5 30 43.3  Minimum 0.2 0.55 0 — — — — 28 6.2 81 398 8 22 21 20  Maximum 0.2 8.8 1.01 — — — — 31.1 13.7 187 609 8.8 51 45 68.8  Std. dev. 0 2.02 0.22 — — — — 0.84 1.24 17.8 45.7 0.16 6.36 6.06 11.2 

N obs. 40 40 40 0 0 0 0 40 40 40 32 40 40 40 40 

3. Backwater Mean 0.2 0.8 0.01 — — — — 31.1 9.71 135 473 8.3 18.7 99 87.5  Median 0.2 0.65 0 — — — — 31.1 7.8 103 480 8.2 19 78 74.9  Minimum 0.2 0.32 0 — — — — 27.9 4.3 61 366 7.7 10 30 24.3  Maximum 0.2 3.4 0.33 — — — — 38.3 25 373 567 8.9 43 230 201  Std. dev. 0 0.59 0.06 — — — — 2.25 5.8 83.9 49.5 0.33 6.93 59.8 45 

N obs. 29 29 29 0 0 0 0 29 29 29 28 29 29 29 29 

4. Lake Mean 0.2 0.6 0 — — — — 29.2 11 148 543 8.4 15 116 108  Median 0.2 0.51 0 — — — — 28.3 9.4 120 526 8.5 15 98 104  Minimum 0.2 0.35 0 — — — — 27.4 5.2 68 486 7.9 12 77 54.2  Maximum 0.2 1.03 0 — — — — 32.4 25 353 656 9.1 20 160 191  Std. dev. 0 0.23 0 — — — — 1.73 6.29 90.3 44.5 0.39 2.1 35.2 33.9 

N obs. 15 15 15 0 0 0 0 15 15 15 15 15 15 15 15 

5. Impounded Mean 0.2 2.04 0.02 — — — — 30.6 12.8 177 468 8.4 37 31 33.4  Median 0.2 1.6 0 — — — — 30.6 9.9 129 464 8.4 35 30 32.8  Minimum 0.2 0.55 0 — — — — 28.3 7.7 101 416 8.1 23 17 14.8  Maximum 0.2 4.7 0.15 — — — — 33.5 25 362 524 8.8 53 58 65  Std. dev. 0 1.25 0.04 — — — — 1.39 6.5 94.2 33.3 0.21 10.4 10.6 14.3 

N obs. 15 15 15 0 0 0 0 15 15 15 15 15 15 15 15 
F-16

Table F-1. Continued.

Samplingstratum Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Tota

suspen

solid

(mg/

1995 Middepth measurements: summer

3. Backwater Mean 0.8 1.09 — — — — — 29.9 3.9 52 488 7.9 — — —  Median 0.8 1.09 — — — — — 29.9 3.9 52 488 7.9 — — —  Minimum 0.8 1.09 — — — — — 29.9 3.9 52 488 7.9 — — —  Maximum 0.8 1.09 — — — — — 29.9 3.9 52 488 7.9 — — —  Std. dev. — — — — — — — — — — — — — — — 

N obs. 1 1 0 — — — — 1 1 1 1 1 — 0 0 

5. Impounded Mean 2.3 4.7 — — — — — 29.5 7.1 95 480 8.1 — — —  Median 2.3 4.7 — — — — — 29.5 7.1 95 480 8.1 — — —  Minimum 2.3 4.7 — — — — — 29.5 7.1 95 480 8.1 — — —  Maximum 2.3 4.7 — — — — — 29.5 7.1 95 480 8.1 — — —  Std. dev. — — — — — — — — — — — — — — — 

N obs. 1 1 0 — — — — 1 1 1 1 1 — 0 0 

1995 Near-bottom measurements: summer

2. Side channel Mean 2.98 3.18 — — — — — 28.9 7.71 102 513 8.1 — — —  Median 2.5 2.7 — — — — — 28.9 7.7 101 502 8.2 — — —  Minimum 1 1.2 — — — — — 28 6 79 459 7.9 — — —  Maximum 8.6 8.8 — — — — — 30.4 9.9 134 607 8.4 — — —  Std. dev. 1.7 1.7 — — — — — 0.69 0.93 13.3 42.2 0.16 — — — 

N obs. 24 24 0 — — — — 24 24 24 17 18 — 0 0 

3. Backwater Mean 1.38 1.6 — — — — — 30.8 5.25 73 486 7.8 — — —  Median 1 1.23 — — — — — 29.8 4.85 65 493 7.9 — — —  Minimum 0.9 1.1 — — — — — 27.8 3.8 52 440 7.5 — — —  Maximum 3.2 3.4 — — — — — 38.3 8.3 133 510 8.2 — — —  Std. dev. 0.9 0.89 — — — — — 3.86 1.56 29.6 27.2 0.29 — — — 

N obs. 6 6 0 — — — — 6 6 6 5 5 — 0 0 

4. Lake Mean 0.8 1.03 — — — — — 28.1 6 78 533 8.2 — — —  Median 0.8 1.03 — — — — — 28.1 6 78 533 8.2 — — —  Minimum 0.8 1.03 — — — — — 28.1 6 78 533 8.2 — — —  Maximum 0.8 1.03 — — — — — 28.1 6 78 533 8.2 — — —  Std. dev. — — — — — — — — — — — — — — — 

N obs. 1 1 0 — — — — 1 1 1 1 1 — 0 0 
F-17

Table F-1. Continued.

Samplingstratum Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Tota

suspen

solid

(mg/

1995 Near-bottom measurements: summer

5. Impounded Mean 2.14 2.35 — — — — — 29.9 8.66 118 477 8.1 — 38 64.5  Median 1.7 1.9 — — — — — 29.5 7.75 102 475 8.2 — 28 77.6  Minimum 0.9 1.18 — — — — — 28.1 2.9 38 420 7.7 — 24 21.5  Maximum 4.5 4.7 — — — — — 33.4 25 361 514 8.7 — 71 114  Std. dev. 1.21 1.2 — — — — — 1.32 5.49 80.9 30 0.26 — 22.4 39.1 

N obs. 12 12 0 — — — — 12 12 12 11 12 — 4 5 

1995 Near-surface measurements: fall

1. Main channel Mean 0.2 5.48 — — — — — 17 9.56 99 412 7.9 40.2 27 39  Median 0.2 5.9 — — — — — 17.2 9.6 99 400 7.9 40 24 33.8  Minimum 0.2 0.54 — — — — — 15.7 9.1 96 390 7.3 25 16 17.5  Maximum 0.2 11.6 — — — — — 18.1 10 104 514 8 59 52 84.2  Std. dev. 0 2.58 — — — — — 0.68 0.21 1.95 28.2 0.14 9.91 10 20.6 

N obs. 21 21 0 0 0 0 0 21 21 21 21 21 21 21 21 

2. Side channel Mean 0.2 3.48 0.41 — — — — 16.8 9.67 100 429 7.9 36 32 46.1  Median 0.2 3.4 0.42 — — — — 17 9.6 99 408 7.8 34 27 38.8  Minimum 0.2 0.5 0 — — — — 15.2 8.4 85 391 7.7 14 15 9.9  Maximum 0.2 7.3 0.8 — — — — 19 14.3 148 551 8.7 59 60 88.6  Std. dev. 0 1.99 0.21 — — — — 0.8 0.89 8.92 49.4 0.17 9.36 12.1 19.8 

N obs. 41 41 41 0 0 0 0 41 41 41 41 40 41 41 41 

3. Backwater Mean 0.2 0.69 0 — — — — 16.8 9.18 95 489 8.1 20 70 80.7  Median 0.2 0.65 0 — — — — 16.3 9.4 101 439 8.1 18 60 62.1  Minimum 0.2 0.3 0 — — — — 14 5.1 54 408 7.4 9 23 24.3  Maximum 0.2 1 0 — — — — 21.3 13.4 138 729 8.7 35 180 243  Std. dev. 0 0.21 0 — — — — 1.87 2.07 21.3 103 0.36 7.29 40.5 53.8 

N obs. 29 29 29 0 0 0 0 29 29 29 28 29 29 29 29 

4. Lake Mean 0.2 0.61 0 — — — — 17.9 14.2 151 620 8.8 18.6 59 71.2  Median 0.2 0.6 0 — — — — 17 11.4 123 597 8.8 18 58 72.1  Minimum 0.2 0.31 0 — — — — 15.9 9.4 95 562 8.5 14 32 56.6  Maximum 0.2 1.05 0 — — — — 20.3 25 277 708 9.3 25 79 92.3  Std. dev. 0 0.2 0 — — — — 1.67 5.71 64.2 50.6 0.22 2.77 10.4 10.6 

N obs. 15 15 15 0 0 0 0 15 15 15 15 15 15 15 15 
F-18

Table F-1. Continued.

Samplingstratum Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Tota

suspen

solid

(mg/

1995 Near-surface measurements: fall

5. Impounded Mean 0.2 2.31 0 — — — — 18 9.97 106 409 8.1 30.7 29 31.6  Median 0.2 1.8 0 — — — — 18.1 9.9 106 411 8.1 31 26 29.6  Minimum 0.2 0.98 0 — — — — 15.7 8.6 87 394 7.9 24 20 19.3  Maximum 0.2 4.8 0 — — — — 21.1 12.2 135 414 8.4 39 46 54.7  Std. dev. 0 1.32 0 — — — — 1.72 0.94 13.5 5.78 0.15 4.33 7.33 9.52 

N obs. 15 15 15 0 0 0 0 15 15 15 15 15 15 15 15 

1995 Near-bottom measurements: fall

2. Side channel Mean 3.16 3.36 — — — — — 17 9.32 96 444 7.9 — — —  Median 3.2 3.4 — — — — — 17.2 9.4 97 411 7.8 — — —  Minimum 1 1.2 — — — — — 15.8 8.2 86 391 7.7 — — —  Maximum 6.8 7 — — — — — 18.4 10.6 107 551 8.5 — — —  Std. dev. 1.89 1.89 — — — — — 0.75 0.63 5.42 59 0.16 — — — 

N obs. 21 21 0 — — — — 21 21 21 21 21 — 0 0 

3. Backwater Mean 0.8 1 — — — — — 16.3 7.8 80 — — — — —  Median 0.8 1 — — — — — 16.3 7.8 80 — — — — —  Minimum 0.8 1 — — — — — 16.3 7.8 80 — — — — —  Maximum 0.8 1 — — — — — 16.3 7.8 80 — — — — —  Std. dev. — — — — — — — — — — — — — — — 

N obs. 1 1 0 — — — — 1 1 1 0 0 — 0 0 

4. Lake Mean 0.8 1.05 — — — — — 16.2 7.6 77 593 — — — —  Median 0.8 1.05 — — — — — 16.2 7.6 77 593 — — — —  Minimum 0.8 1.05 — — — — — 16.2 7.6 77 593 — — — —  Maximum 0.8 1.05 — — — — — 16.2 7.6 77 593 — — — —  Std. dev. — — — — — — — — — — — — — — — 

N obs. 1 1 0 — — — — 1 1 1 1 0 — 0 0 

5. Impounded Mean 2.21 2.41 — — — — — 17.6 9.19 97 410 8 — — —  Median 1.6 1.8 — — — — — 17.5 9.25 97 412 8 — — —  Minimum 0.8 1.04 — — — — — 15.8 7.6 80 393 7.8 — — —  Maximum 4.6 4.8 — — — — — 19.4 10.6 115 418 8.4 — — —  Std. dev. 1.32 1.32 — — — — — 1.34 0.89 11.4 6.87 0.17 — — — 

N obs. 14 14 0 — — — — 14 14 14 14 14 — 0 0 
F-19

Table F-1. Continued.

Samplingstratum Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Tota

suspen

solid

(mg/

1996 Near-surface measurements: winter

1. Main channel Mean 0.2 6.97 0 53.9 10 1 0 0.2 12.9 89 515 7.7 62.4 24 31.3  Median 0.2 6.5 0 60 11 0 0 0.1 12.6 86 492 7.6 37 27 33.7  Minimum 0.2 0.5 0 5 2 0 0 0 12.1 83 298 7.4 19 5 3.9  Maximum 0.2 15.7 0 100 20 20 2 2.1 15.1 104 953 8.8 174 54 67.1  Std. dev. 0 4.12 — 31.7 3.86 4.59 .46 0.46 0.84 6.47 122 0.39 49.8 14 21.2 

N obs. 20 20 1 19 19 19 19 20 20 20 20 20 19 20 20 

2. Side channel Mean 0.2 3.53 0.36 57 12 9 0 0.11 13.2 90 490 7.7 50.8 20 25.6  Median 0.2 3 0.22 55 9 0 0 0 12.6 86 479 7.6 39 22 28.2  Minimum 0.2 0.46 0 5 1 0 0 0 12 82 110 7.4 27 5 3.8  Maximum 0.2 10.1 0.72 100 25 100 2 1 20 141 641 8.9 121 35 49.3  Std. dev. 0 2.28 0.27 37.5 6.66 23.8 .59 0.22 1.83 13.3 129 0.44 24.5 10.5 15.8 

N obs. 37 37 35 37 37 37 37 37 37 37 37 36 32 37 37 

3. Backwater Mean 0.2 0.71 0 96.3 17 42 1 2.68 17.9 132 539 8.5 44.8 18 16.7  Median 0.2 0.71 0 100 17 25 1 3 19 139 519 8.5 45 17 14.7  Minimum 0.2 0.31 0 15 3 0 0 0.2 4.6 34 250 7.8 20 5 4.7  Maximum 0.2 1.24 0 100 25 100 3 4.5 25 192 893 8.8 66 95 61.1  Std. dev. 0 0.23 0 14.7 4.26 37.8 .76 1.38 3.65 28 122 0.31 11.7 15.8 11.1 

N obs. 34 34 34 34 34 34 34 34 34 34 34 20 24 34 34 

5. Impounded Mean 0.2 1.62 0 99.3 17 45 1 0.44 14 97 576 8 84.1 9 6  Median 0.2 1.5 0 100 17 35 1 0.4 14.1 97 556 8 80 9 6.6  Minimum 0.2 0.43 0 90 10 0 0 0 12.5 86 540 7.7 65 4 3  Maximum 0.2 3.5 0 100 23 100 2 0.8 14.8 104 710 8.2 117 13 8.2  Std. dev. 0 1.03 0 2.58 4.19 42.9 .86 0.24 0.56 4.02 49.8 0.15 17.4 2.67 1.78 

N obs. 15 15 15 15 15 15 15 15 15 15 15 15 9 15 15 

1996 Near-bottom measurements: winter

1. Main channel Mean 1.2 1.4 — — — — — 0.5 14.9 103 — — — — —  Median 1.2 1.4 — — — — — 0.5 14.9 103 — — — — —  Minimum 1.2 1.4 — — — — — 0.5 14.9 103 — — — — —  Maximum 1.2 1.4 — — — — — 0.5 14.9 103 — — — — —  Std. dev. — — — — — — — — — — — — — — — 

N obs. 1 1 0 — — — — 1 1 1 0 0 — 0 0 
F-20

Table F-1. Continued.

Samplingstratum Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Tota

suspen

solid

(mg/

1996 Near-bottom measurements: winter

2. Side channel Mean 3.81 4.01 — — — — — 0.05 12.5 85 538 7.6 — — —  Median 3.4 3.6 — — — — — 0 12.6 86 517 7.6 — — —  Minimum 1.2 1.4 — — — — — 0 12.1 83 362 7.4 — — —  Maximum 7.4 7.6 — — — — — 0.3 12.9 89 641 7.8 — — —  Std. dev. 1.98 1.98 — — — — — 0.07 0.3 2.11 89.5 0.13 — — — 

N obs. 21 21 0 — — — — 21 21 21 21 21 — 0 0 

3. Backwater Mean 0.9 1.16 — — — — — 3.65 15.5 117 514 — — — —  Median 0.9 1.16 — — — — — 3.65 15.5 117 514 — — — —  Minimum 0.8 1.07 — — — — — 3.1 13.9 104 490 — — — —  Maximum 1 1.24 — — — — — 4.2 17 130 537 — — — —  Std. dev. 0.14 0.12 — — — — — 0.78 2.19 19 33.2 — — — — 

N obs. 2 2 0 — — — — 2 2 2 2 0 — 0 0 

5. Impounded Mean 2.04 2.24 — — — — — 0.9 13.9 97 557 7.9 — — —  Median 1.8 2 — — — — — 0.9 13.8 98 556 7.9 — — —  Minimum 1.1 1.3 — — — — — 0.2 13.3 92 544 7.9 — — —  Maximum 3.3 3.5 — — — — — 1.7 14.8 105 572 8 — — —  Std. dev. 0.85 0.85 — — — — — 0.47 0.48 3.82 7.71 0.05 — — — 

N obs. 9 9 0 — — — — 9 9 9 8 8 — 0 0 

1996 Near-surface measurements: spring

1. Main channel Mean 0.2 5.86 0.6 — — — — 12.5 10.5 98 384 7.9 25.9 97 170  Median 0.2 5.8 0.6 — — — — 12.5 10.4 97 376 8 25 68 136  Minimum 0.2 1.5 0.6 — — — — 11.3 9.1 85 282 7.5 13 27 43.6  Maximum 0.2 10.7 0.6 — — — — 14 12.4 118 593 8.3 76 330 491  Std. dev. 0 2.68 — — — — — 0.71 0.95 9.67 70.4 0.26 13.7 77.8 109 

N obs. 21 21 1 0 0 0 0 21 21 21 21 21 21 21 21 

2. Side channel Mean 0.2 4.09 0.75 — — — — 12.6 10.1 95 386 7.9 22.1 97 160  Median 0.2 4 0.82 — — — — 12.5 10.5 97 373 7.9 23 66 130  Minimum 0.2 0.38 0 — — — — 11.3 5.6 57 241 7.5 9 37 61.8  Maximum 0.2 10.1 1.3 — — — — 16.2 11 103 698 8.2 34 290 601  Std. dev. 0 2.36 0.34 — — — — 0.99 1 8.36 94 0.19 6.87 66.7 98.5 

N obs. 41 41 41 0 0 0 0 41 41 41 41 41 41 41 41 
F-21

Table F-1. Continued.

Samplingstratum Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Tota

suspen

solid

(mg/

1996 Near-surface measurements: spring

3. Backwater Mean 0.2 0.94 0.04 — — — — 15.4 9.25 93 313 7.9 19.1 152 154  Median 0.2 0.78 0 — — — — 16.1 9.1 92 333 8 12.5 175 135  Minimum 0.2 0.3 0 — — — — 11.5 5.4 55 153 7.1 7 10 11.5  Maximum 0.2 2.4 0.59 — — — — 18.6 25 262 515 8.9 66 300 425  Std. dev. 0 0.54 0.11 — — — — 2.02 3.6 37.3 81 0.51 14.5 98.9 108 

N obs. 30 30 30 0 0 0 0 30 30 30 30 30 30 30 29 

4. Lake Mean 0.2 1.12 0 — — — — 14.9 11.3 113 607 8.2 15.9 119 113  Median 0.2 1.45 0 — — — — 13.9 10.4 101 614 8.1 15 95 85.4  Minimum 0.2 0.28 0 — — — — 12.8 8.7 83 490 7.7 11 45 48.9  Maximum 0.2 1.6 0 — — — — 17.9 15.9 166 851 8.8 27 290 356  Std. dev. 0 0.55 0 — — — — 2.03 2.26 26.7 108 0.3 3.79 71.2 76.3 

N obs. 14 14 14 0 0 0 0 14 14 14 14 14 14 14 14 

5. Impounded Mean 0.2 1.89 0.05 — — — — 14.2 10.8 105 363 8.5 24.4 64 75.5  Median 0.2 1.8 0 — — — — 14.1 10.8 107 372 8.5 25 56 53.2  Minimum 0.2 0.35 0 — — — — 12.6 9.1 86 287 8.2 12 35 41.1  Maximum 0.2 3.4 0.73 — — — — 15.5 12.2 117 399 8.6 30 210 291  Std. dev. 0 1.04 0.2 — — — — 0.99 0.9 10 32.8 0.11 5.28 43.3 62.8 

N obs. 15 15 14 0 0 0 0 15 15 15 15 15 15 15 15 

1996 Middepth measurements: spring

4. Lake Mean 0.4 1.6 0 — — — — 13.9 10.3 100 484 8.1 — 150 337  Median 0.4 1.6 0 — — — — 13.9 10.3 100 484 8.1 — 150 337  Minimum 0.4 1.6 0 — — — — 13.9 10.3 100 484 8.1 — 150 337  Maximum 0.4 1.6 0 — — — — 13.9 10.3 100 484 8.1 — 150 337  Std. dev. — — — — — — — — — — — — — — — 

N obs. 1 1 1 — — — — 1 1 1 1 1 — 1 1 

1996 Near-bottom measurements: spring

2. Side channel Mean 2.87 3.07 — — — — — 12.9 9.87 93 438 8 — — —  Median 2.8 3 — — — — — 12.6 10.1 95 375 8 — — —  Minimum 1.6 1.8 — — — — — 11.4 8.2 80 331 7.6 — — —  Maximum 5 5.2 — — — — — 14.8 10.8 101 698 8.1 — — —  Std. dev. 1.11 1.11 — — — — — 0.95 0.93 7.33 130 0.14 — — — 

N obs. 15 15 0 — — — — 15 15 15 15 15 — 0 0 
F-22

Table F-1. Continued.

Samplingstratum Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Tota

suspen

solid

(mg/

1996 Near-bottom measurements: spring

3. Backwater Mean 1.24 1.47 — — — — — 14.8 7.84 77 308 7.6 — 18 19.6  Median 1 1.25 — — — — — 15.7 6.2 64 310 7.4 — 18 19.6  Minimum 0.8 1.07 — — — — — 11.1 4.6 47 207 7.1 — 18 19.6  Maximum 2.2 2.4 — — — — — 16.9 15 151 403 8.7 — 18 19.6  Std. dev. 0.52 0.5 — — — — — 2 3.31 32.2 82.9 0.56 — — — 

N obs. 9 9 0 — — — — 9 9 9 8 8 — 1 1 

4. Lake Mean 1.32 1.52 — — — — — 13.3 9.77 93 547 8 — — —  Median 1.3 1.5 — — — — — 13.4 9.9 95 498 8.1 — — —  Minimum 1.2 1.4 — — — — — 12.6 8.3 78 484 7.7 — — —  Maximum 1.4 1.6 — — — — — 13.9 11.7 110 651 8.4 — — —  Std. dev. 0.08 0.08 — — — — — 0.44 0.96 9.26 73.5 0.19 — — — 

N obs. 10 10 0 — — — — 10 10 10 10 10 — 0 0 

5. Impounded Mean 2.3 2.5 — — — — — 13.9 10.6 103 — — — — —  Median 2.5 2.7 — — — — — 14.1 10.8 107 — — — — —  Minimum 1.3 1.5 — — — — — 12.5 9 84 — — — — —  Maximum 3.2 3.4 — — — — — 14.9 12.2 116 — — — — —  Std. dev. 0.65 0.65 — — — — — 0.96 0.96 10.4 — — — — — 

N obs. 10 10 0 — — — — 10 10 10 0 0 — 0 0 

1996 Near-surface measurements: summer

1. Main channel Mean 0.2 5.9 — — — — — 25.9 5.99 74 508 7.8 21.1 83 116  Median 0.2 5.6 — — — — — 26.2 6 75 498 7.8 21 75 121  Minimum 0.2 1.2 — — — — — 24.7 3.1 39 443 7.5 10 32 39.5  Maximum 0.2 13.2 — — — — — 26.6 7.5 92 699 8 31 220 164  Std. dev. 0 3.17 — — — — — 0.55 1.13 13.9 64.7 0.17 5.67 47.4 32.1 

N obs. 20 20 0 0 0 0 0 20 15 15 20 20 20 20 20 

2. Side channel Mean 0.2 3.38 0.6 — — — — 25.7 6.83 84 481 7.8 24.8 65 95.2  Median 0.2 2.65 0.65 — — — — 25.8 7.4 90 464 7.8 25 48 76.5  Minimum 0.2 0.65 0.11 — — — — 24.9 3.5 44 441 7.5 11 29 34.3  Maximum 0.2 9.5 1.05 — — — — 27 7.9 98 664 8.2 37 320 177  Std. dev. 0 2.29 0.22 — — — — 0.51 1.12 13.5 52.4 0.14 6.71 49.7 43 

N obs. 42 42 42 0 0 0 0 42 35 35 42 42 42 41 42 
F-23

Table F-1. Continued.

Samplingstratum Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Tota

suspen

solid

(mg/

1996 Near-surface measurements: summer

3. Backwater Mean 0.2 0.61 0 — — — — 27.3 8.89 115 490 8.1 14.1 108 123  Median 0.2 0.49 0 — — — — 27 7.9 97 479 8.1 14 86 107  Minimum 0.2 0.3 0 — — — — 22.8 4.7 57 392 7.5 9 24 23.4  Maximum 0.2 2.3 0 — — — — 30.7 25 329 603 9 36 270 262  Std. dev. 0 0.38 0 — — — — 1.99 5.17 69.4 54.5 0.42 5.2 54.8 58.9 

N obs. 29 29 29 0 0 0 0 29 27 27 29 29 29 29 29 

4. Lake Mean 0.2 0.61 0 — — — — 26.9 9.01 114 543 8.6 15.7 82 100  Median 0.2 0.6 0 — — — — 26.7 8.5 107 550 8.6 16 74 103  Minimum 0.2 0.37 0 — — — — 25.2 6.8 85 486 8.3 11 49 54.7  Maximum 0.2 0.8 0 — — — — 29 11.8 156 582 9 19 180 146  Std. dev. 0 0.13 0 — — — — 1.08 1.62 21.7 28 0.21 1.91 32.1 23.4 

N obs. 15 15 15 0 0 0 0 15 15 15 15 15 15 15 15 

5. Impounded Mean 0.2 1.65 0.02 — — — — 27.5 11 142 480 8.2 24.3 45 58.7  Median 0.2 0.95 0 — — — — 27.4 9 115 486 8.2 25 44 52.1  Minimum 0.2 0.35 0 — — — — 26.4 6.2 78 410 7.9 11 23 28.3  Maximum 0.2 4.1 0.16 — — — — 29 25 329 504 8.8 33 79 106  Std. dev. 0 1.36 0.05 — — — — 0.88 5.9 78.3 23 0.29 6.3 16.7 25.9 

N obs. 15 15 15 0 0 0 0 15 15 15 15 15 15 15 15 

1996 Near-bottom measurements: summer

2. Side channel Mean 1.95 2.15 — — — — — 25.6 6.62 82 487 7.8 — — —  Median 1.7 1.9 — — — — — 25.5 7.3 90 452 7.8 — — —  Minimum 1 1.2 — — — — — 24.9 3.4 43 441 7.5 — — —  Maximum 5.9 6.1 — — — — — 26.8 7.9 98 665 7.9 — — —  Std. dev. 1.15 1.14 — — — — — 0.53 1.42 17.2 77.3 0.11 — — — 

N obs. 20 20 0 — — — — 20 18 18 18 18 — 0 0 

3. Backwater Mean 1.45 1.66 — — — — — 27.7 7 92 602 — — — —  Median 1.45 1.66 — — — — — 27.7 7 92 602 — — — —  Minimum 0.8 1.02 — — — — — 26.5 7 92 602 — — — —  Maximum 2.1 2.3 — — — — — 28.9 7 92 602 — — — —  Std. dev. 0.92 0.91 — — — — — 1.7 — — — — — — — 

N obs. 2 2 0 — — — — 2 1 1 1 0 — 0 0 
F-24

Table F-1. Continued.

Samplingstratum Statistic

Sample

depth

(m)

Water

depth

(m)

Water

velocity

(m/s)

Ice

cover

(%)

Thickness

of ice

 (cm)

Snow

cover

(%)

Snow

depth

(cm)

Water

temp.

(oC)

Dissolved

oxygen

(mg/L)

Oxygen

saturation

(%)

Specific

cond.

(:S) pH

Secchi

depth

(cm)

Turbidity

(NTU)

Tota

suspen

solid

(mg/L

1996 Near-bottom measurements: summer

5. Impounded Mean 2.92 3.12 — — — — — 26.3 7.18 90 489 7.9 — — —  Median 3 3.2 — — — — — 26.5 7.4 93 486 8 — — —  Minimum 1.3 1.5 — — — — — 25.2 4.6 56 486 7.8 — — —  Maximum 3.9 4.1 — — — — — 27 9 114 498 8 — — —  Std. dev. 0.9 0.9 — — — — — 0.66 1.51 20 6 0.12 — — — 

N obs. 6 6 0 — — — — 6 6 6 4 3 — 0 0 

1996 Near-surface measurements: fall

1. Main channel Mean 0.2 6.09 — — — — — 17.2 9.28 96 451 8.2 54.4 15 19.8  Median 0.2 5.5 — — — — — 17.3 9.6 98 442 8.2 55.5 15 19.3  Minimum 0.2 1.5 — — — — — 15.9 8.3 87 419 7.8 42 12 15.4  Maximum 0.2 14 — — — — — 19.4 9.8 104 509 8.5 67 18 33.4  Std. dev. 0 3.26 — — — — — 1.05 0.57 5.43 32.5 0.18 6.96 1.42 3.83 

N obs. 20 20 0 0 0 0 0 20 20 20 20 20 20 20 20 

2. Side channel Mean 0.2 3.87 0.2 — — — — 17 9.39 97 439 8.1 55.5 17 23.4  Median 0.2 3.6 0.22 — — — — 16.8 9.6 99 422 8.2 57 14 20.4  Minimum 0.2 0.45 0 — — — — 14 7.6 74 413 7.8 24 10 14.3  Maximum 0.2 9.5 0.45 — — — — 19.7 10.2 110 549 8.5 76 51 54.6  Std. dev. 0 2.37 0.11 — — — — 0.99 0.63 6.63 41.3 0.14 13 8.2 9.35 

N obs. 42 42 38 0 0 0 0 42 42 42 42 42 42 42 42 

3. Backwater Mean 0.2 0.99 0 — — — — 17.8 9.13 97 451 8.3 24.9 56 59.1  Median 0.2 0.7 0 — — — — 17.8 8.9 93 429 8.3 25 52 55.5  Minimum 0.2 0.3 0 — — — — 12.5 4.4 41 399 7.6 11 15 11.6  Maximum 0.2 5 0 — — — — 23.5 15.8 176 687 9.1 45 160 223  Std. dev. 0 0.94 0 — — — — 2.45 2.13 25.4 63.6 0.33 7.62 29.5 38.6 

N obs. 29 29 29 0 0 0 0 29 29 29 29 29 28 29 29 

5. Impounded Mean 0.2 2.33 0 — — — — 18.5 10 108 424 8.3 32.3 26 29.6  Median 0.2 2.5 0 — — — — 19.6 9.5 104 425 8.2 32 23 24.2  Minimum 0.2 0.9 0 — — — — 13.7 7.8 75 402 7.8 25 19 14.3  Maximum 0.2 4.5 0 — — — — 20.8 16.9 189 443 9 38 37 87.2  Std. dev. 0 1.33 0 — — — — 2.21 2.49 30.7 14.3 0.32 4.01 5.97 17.3 

N obs. 15 15 15 0 0 0 0 15 15 15 15 15 15 15 15 
F-25

Table F-2. Summaries of chemical measurements during each stratified random sampling episode from 1993 through 1996. Data are grdepth categories: near surface (less than 0.2 m below the surface), middepth, and near bottom (less than 0.2 m above the substrate).

Sampling stratum Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sodium

(mg/L)

1993 Near-surface measurements: fall

1. Main channel Mean 3.924 0.05 2.684 0.223 0.068 — — — — —  Median 3.89 0.048 2.568 0.211 0.063 — — — — —  Minimum 3.212 -0.02 2.238 0.16 0.023 — — — — —  Maximum 5.079 0.104 3.596 0.323 0.135 — — — — —  Std. dev. 0.52 0.029 0.406 0.053 0.035 — — — — — 

N obs. 11 11 11 11 11 0 0 0 0 0 

2. Side channel Mean 4.009 0.05 2.553 0.228 0.055 — — — — —  Median 3.946 0.047 2.414 0.213 0.045 — — — — —  Minimum 3.023 -0.02 1.302 0.143 -0.01 — — — — —  Maximum 4.904 0.101 3.681 0.343 0.142 — — — — —  Std. dev. 0.376 0.033 0.567 0.046 0.043 — — — — — 

N obs. 20 21 21 20 21 0 0 0 0 0 

3. Backwater Mean 2.944 0.193 0.767 0.201 0.035 — — — — —  Median 2.68 0.059 0.511 0.205 0.034 — — — — —  Minimum 1.91 -0.02 -0.01 0.112 -0.01 — — — — —  Maximum 4.935 0.524 2.416 0.285 0.062 — — — — —  Std. dev. 1.028 0.196 0.818 0.048 0.018 — — — — — 

N obs. 9 10 10 9 10 0 0 0 0 0 

4. Lake Mean 3.137 0.035 1.398 0.242 0.046 — — — — —  Median 2.809 -0.02 1.183 0.235 0.045 — — — — —  Minimum 2.256 -0.02 0.785 0.152 0.023 — — — — —  Maximum 4.079 0.101 2.134 0.401 0.07 — — — — —  Std. dev. 0.704 0.034 0.515 0.074 0.017 — — — — — 

N obs. 8 8 8 8 8 0 0 0 0 0 

5. Impounded Mean 3.121 0.061 1.808 0.163 0.048 — — — — —  Median 3.049 0.058 1.605 0.158 0.05 — — — — —  Minimum 2.445 0.025 1.409 0.142 0.032 — — — — —  Maximum 4.129 0.094 2.25 0.191 0.064 — — — — —  Std. dev. 0.505 0.031 0.329 0.02 0.011 — — — — — 

N obs. 8 8 8 8 8 0 0 0 0 0 
F-26

Table F-2. Continued.

Sampling stratum Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sod

(mg

1994 Near-surface measurements: winter

1. Main channel Mean 4.528 0.225 3.247 0.138 0.084 — — — —  Median 3.872 0.196 3.214 0.124 0.075 — — — —  Minimum 3.104 0.173 2.903 0.108 0.064 — — — —  Maximum 9.192 0.33 3.822 0.235 0.143 — — — —  Std. dev. 1.793 0.057 0.238 0.038 0.025 — — — — 

N obs. 10 10 10 10 10 0 0 0 0 

2. Side channel Mean 4.153 0.189 3.272 0.141 0.079 — — — —  Median 3.696 0.196 3.284 0.131 0.075 — — — —  Minimum 3.279 -0.02 2.551 0.112 0.015 — — — —  Maximum 6.391 0.386 4.06 0.253 0.18 — — — —  Std. dev. 0.879 0.091 0.358 0.038 0.037 — — — — 

N obs. 13 13 13 13 13 0 0 0 0 

3. Backwater Mean 1.609 0.039 0.248 0.151 0.009 — — — —  Median 1.339 -0.02 0.153 0.085 -0.01 — — — —  Minimum 0.262 -0.02 -0.01 0.063 -0.01 — — — —  Maximum 2.955 0.087 0.53 0.302 0.016 — — — —  Std. dev. 1.175 0.033 0.228 0.099 0.005 — — — — 

N obs. 6 6 6 6 6 0 0 0 0 

5. Impounded Mean 3.201 0.166 2.612 0.124 0.056 — — — —  Median 2.854 0.164 2.046 0.129 0.056 — — — —  Minimum 2.579 0.118 2.007 0.106 0.015 — — — —  Maximum 3.865 0.204 3.201 0.131 0.081 — — — —  Std. dev. 0.589 0.036 0.676 0.012 0.029 — — — — 

N obs. 4 4 4 4 4 0 0 0 0 

1994 Near-surface measurements: spring

1. Main channel Mean 2.562 0.05 1.196 0.319 0.008 0.531 — — —  Median 2.237 0.055 0.882 0.301 -0.01 0.297 — — —  Minimum 1.986 -0.02 0.712 0.236 -0.01 -0.05 — — —  Maximum 5.081 0.096 4.33 0.47 0.013 2.66 — — —  Std. dev. 0.908 0.027 1.048 0.069 0.004 0.783 — — — 

N obs. 11 11 11 11 11 11 0 0 0 
F-27

Table F-2. Continued.

Sampling stratum Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sod

(mg

1994 Near-surface measurements: spring

2. Side channel Mean 2.794 0.05 1.319 0.323 0.01 0.751 — — —  Median 2.426 0.048 0.861 0.299 -0.01 0.367 — — —  Minimum 2.003 -0.02 0.639 0.204 -0.01 -0.05 — — —  Maximum 5.037 0.143 4.688 0.464 0.033 4.31 — — —  Std. dev. 0.917 0.03 1.098 0.07 0.007 1.057 — — — 

N obs. 22 22 22 22 22 22 0 0 0 

3. Backwater Mean 2.593 0.088 1.051 0.353 0.008 1.831 — — —  Median 2.304 0.047 0.969 0.278 -0.01 1.934 — — —  Minimum 1.358 -0.02 0.137 0.19 -0.01 0.087 — — —  Maximum 4.328 0.231 2.654 0.972 0.032 3.099 — — —  Std. dev. 0.892 0.087 0.599 0.19 0.007 0.818 — — — 

N obs. 15 15 15 15 15 15 0 0 0 

4. Lake Mean 3.814 0.03 3.02 0.281 0.016 2.32 — — —  Median 3.655 -0.02 2.926 0.27 0.013 2.455 — — —  Minimum 3.292 -0.02 2.339 0.23 -0.01 0.773 — — —  Maximum 4.399 0.112 3.898 0.326 0.034 3.094 — — —  Std. dev. 0.455 0.036 0.518 0.039 0.013 0.77 — — — 

N obs. 8 8 8 8 7 7 0 0 0 

5. Impounded Mean 2.765 0.229 0.937 0.298 0.015 1.677 — — —  Median 2.256 0.1 0.899 0.265 0.012 1.099 — — —  Minimum 1.993 0.082 0.877 0.199 -0.01 0.881 — — —  Maximum 5.934 0.612 1.016 0.418 0.039 2.978 — — —  Std. dev. 1.306 0.204 0.06 0.072 0.011 0.887 — — — 

N obs. 8 8 8 8 8 8 0 0 0 

1994 Near-surface measurements: summer

1. Main channel Mean 3.407 0.017 1.939 0.089 0.02 4.114 — — —  Median 3.381 -0.02 2.095 0.06 0.014 4.299 — — —  Minimum 2.743 -0.02 1.039 0.044 -0.01 1.652 — — —  Maximum 4.444 0.04 2.654 0.16 0.073 5.703 — — —  Std. dev. 0.514 0.012 0.554 0.048 0.02 1.123 — — — 

N obs. 11 11 11 11 11 11 0 0 0 
F-28

Table F-2. Continued.

Sampling stratum Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sod

(mg

1994 Near-surface measurements: summer

2. Side channel Mean 3.506 0.015 1.993 0.094 0.023 4.295 — — —  Median 3.66 -0.02 2.246 0.072 0.018 4.537 — — —  Minimum 1.899 -0.02 -0.01 0.037 -0.01 -0.05 — — —  Maximum 4.324 0.039 2.775 0.16 0.099 5.724 — — —  Std. dev. 0.622 0.008 0.755 0.043 0.021 1.21 — — — 

N obs. 21 21 21 21 21 21 0 0 0 

3. Backwater Mean 2.752 0.027 0.521 0.094 0.012 1.662 — — —  Median 1.916 -0.02 0.142 0.095 -0.01 1.236 — — —  Minimum 0.951 -0.02 -0.01 0.036 -0.01 0.321 — — —  Maximum 12.3 0.23 2.617 0.154 0.056 3.749 — — —  Std. dev. 2.609 0.053 0.818 0.039 0.015 1.222 — — — 

N obs. 17 17 17 17 17 17 0 0 0 

5. Impounded Mean 3.397 0.027 1.946 0.06 0.009 4.002 — — —  Median 3.183 -0.02 1.691 0.041 -0.01 3.893 — — —  Minimum 2.247 -0.02 1.338 0.028 -0.01 2.789 — — —  Maximum 4.275 0.086 2.609 0.143 0.03 5.682 — — —  Std. dev. 0.74 0.027 0.459 0.038 0.009 0.969 — — — 

N obs. 8 8 8 8 8 8 0 0 0 

1994 Near-surface measurements: fall

1. Main channel Mean 2.33 0.013 1.736 0.145 0.036 5.214 — — —  Median 2.343 -0.02 1.71 0.139 0.035 5.213 — — —  Minimum 1.339 -0.02 1.627 0.119 0.016 4.553 — — —  Maximum 2.957 0.04 1.881 0.194 0.054 5.751 — — —  Std. dev. 0.394 0.009 0.093 0.027 0.012 0.322 — — — 

N obs. 11 11 11 11 11 11 0 0 0 

2. Side channel Mean 2.377 0.019 1.767 0.149 0.036 5.115 — — —  Median 2.33 -0.02 1.739 0.139 0.03 5.203 — — —  Minimum 1.961 -0.02 1.625 0.114 -0.01 3.722 — — —  Maximum 2.957 0.106 1.996 0.2 0.1 5.751 — — —  Std. dev. 0.252 0.022 0.1 0.024 0.025 0.465 — — — 

N obs. 21 22 22 21 21 21 0 0 0 
F-29

Table F-2. Continued.

Sampling stratum Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sod

(mg

1994 Near-surface measurements: fall

3. Backwater Mean 1.594 0.021 0.341 0.187 0.032 3.59 — — —  Median 1.471 -0.02 0.293 0.2 0.013 3.53 — — —  Minimum 0.989 -0.02 -0.01 0.085 -0.01 1.376 — — —  Maximum 2.217 0.116 0.951 0.373 0.267 5.725 — — —  Std. dev. 0.385 0.028 0.299 0.075 0.064 1.404 — — — 

N obs. 15 15 15 15 16 16 0 0 0 

4. Lake Mean 1.63 0.022 0.289 0.26 0.023 3.153 — — —  Median 1.64 -0.02 -0.01 0.253 0.022 3.26 — — —  Minimum 0.827 -0.02 -0.01 0.145 -0.01 1.442 — — —  Maximum 2.518 0.06 1.871 0.329 0.053 5.426 — — —  Std. dev. 0.512 0.017 0.643 0.065 0.016 1.171 — — — 

N obs. 8 8 8 8 9 9 0 0 0 

5. Impounded Mean 1.788 0.02 1.237 0.113 0.012 4.036 — — —  Median 1.766 -0.02 1.025 0.109 -0.01 4.036 — — —  Minimum 1.184 -0.02 0.474 0.091 -0.01 1.925 — — —  Maximum 2.28 0.043 1.815 0.134 0.023 5.192 — — —  Std. dev. 0.388 0.012 0.485 0.016 0.007 1.098 — — — 

N obs. 8 8 8 8 8 8 0 0 0 

1995 Near-surface measurements: winter

1. Main channel Mean 4.276 0.057 3.104 0.171 0.021 4.656 — — —  Median 3.989 0.06 3.024 0.13 0.016 4.6 — — —  Minimum 2.889 -0.02 2.192 0.092 -0.01 4.3 — — —  Maximum 6.013 0.123 4.758 0.346 0.057 5.011 — — —  Std. dev. 1.003 0.04 0.622 0.08 0.017 0.219 — — — 

N obs. 10 11 11 10 11 11 0 0 0 

2. Side channel Mean 3.485 0.064 2.558 0.161 0.024 3.84 — — —  Median 3.536 0.043 2.664 0.14 0.014 4.204 — — —  Minimum 1.336 -0.02 0.226 0.046 -0.01 0.568 — — —  Maximum 6.026 0.193 5.353 0.374 0.115 5.098 — — —  Std. dev. 1.335 0.056 1.298 0.089 0.032 1.308 — — — 

N obs. 21 21 21 21 21 21 0 0 0 
F-30

Table F-2. Continued.

Sampling stratum Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sod

(mg

1995 Near-surface measurements: winter

3. Backwater Mean 1.903 0.046 1.029 0.129 0.012 2.027 — — —  Median 1.498 -0.02 0.607 0.118 -0.01 1.451 — — —  Minimum 0.896 -0.02 -0.01 0.039 -0.01 -0.05 — — —  Maximum 3.775 0.169 2.76 0.337 0.03 5.363 — — —  Std. dev. 1.004 0.052 0.96 0.076 0.009 1.93 — — — 

N obs. 13 12 12 13 13 13 0 0 0 

5. Impounded Mean 4.692 0.058 2.635 0.107 0.021 3.784 — — —  Median 3.313 0.05 2.635 0.083 0.012 3.621 — — —  Minimum 3.115 0.03 2.4 0.08 -0.01 3.132 — — —  Maximum 12.83 0.092 2.887 0.167 0.062 4.355 — — —  Std. dev. 3.338 0.022 0.157 0.031 0.022 0.43 — — — 

N obs. 8 8 8 8 8 8 0 0 0 

1995 Near-surface measurements: spring

1. Main channel Mean 6.437 0.07 4.771 0.207 0.014 4.629 — — —  Median 6.241 0.068 4.861 0.209 0.013 4.583 — — —  Minimum 5.163 0.046 4.3 0.143 -0.01 3.78 — — —  Maximum 8.736 0.114 5.047 0.257 0.027 5.161 — — —  Std. dev. 1.061 0.019 0.241 0.033 0.007 0.423 — — — 

N obs. 11 11 11 11 11 8 0 0 0 

2. Side channel Mean 6.729 0.072 4.869 0.206 0.028 4.494 — — —  Median 6.429 0.068 4.843 0.204 0.014 4.742 — — —  Minimum 4.795 0.042 4.205 0.159 -0.01 3.271 — — —  Maximum 13.06 0.129 5.358 0.312 0.24 5.001 — — —  Std. dev. 1.775 0.022 0.287 0.031 0.051 0.588 — — — 

N obs. 22 22 22 22 22 14 0 0 0 

3. Backwater Mean 4.463 0.07 2.435 0.183 0.011 2.176 — — —  Median 4.292 0.048 1.665 0.153 -0.01 0.854 — — —  Minimum 2.347 0.027 -0.01 0.074 -0.01 -0.05 — — —  Maximum 8.756 0.199 5.137 0.42 0.034 4.787 — — —  Std. dev. 1.662 0.051 2.051 0.087 0.009 2.206 — — — 

N obs. 18 18 18 18 18 12 0 0 0 
F-31

Table F-2. Continued.

Sampling stratum Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sod

(mg

1995 Near-surface measurements: spring

4. Lake Mean 4.262 0.04 1.636 0.163 0.007 -0.05 — — —  Median 3.225 0.045 1.229 0.16 -0.01 -0.05 — — —  Minimum 2.607 -0.02 0.741 0.109 -0.01 -0.05 — — —  Maximum 6.04 0.049 3.641 0.194 0.022 -0.05 — — —  Std. dev. 1.512 0.014 1.006 0.028 0.006 0 — — — 

N obs. 8 8 8 8 8 3 0 0 0 

5. Impounded Mean 5.132 0.069 3.303 0.151 0.009 2.117 — — —  Median 4.452 0.086 2.856 0.146 -0.01 1.688 — — —  Minimum 3.676 0.032 2.542 0.107 -0.01 1.366 — — —  Maximum 7.389 0.099 4.164 0.219 0.023 3.993 — — —  Std. dev. 1.412 0.028 0.701 0.037 0.006 0.961 — — — 

N obs. 9 9 9 9 9 6 0 0 0 

1995 Near-surface measurements: summer

1. Main channel Mean 3.967 0.028 2.716 0.17 0.022 — — — —  Median 4.067 0.025 2.911 0.16 0.02 — — — —  Minimum 3.105 -0.02 -0.01 0.137 0.015 — — — —  Maximum 4.532 0.067 3.481 0.213 0.036 — — — —  Std. dev. 0.472 0.016 1.01 0.024 0.007 — — — — 

N obs. 12 12 12 12 12 0 0 0 0 

2. Side channel Mean 3.826 0.031 2.684 0.193 0.029 — — — —  Median 4.021 0.033 2.743 0.18 0.029 — — — —  Minimum 2.482 -0.02 1.669 0.129 0.01 — — — —  Maximum 5.315 0.05 3.478 0.33 0.05 — — — —  Std. dev. 0.675 0.01 0.684 0.048 0.011 — — — — 

N obs. 21 21 21 21 21 0 0 0 0 

3. Backwater Mean 2.876 0.103 0.446 0.382 0.012 — — — —  Median 3.031 0.053 0.073 0.32 0.011 — — — —  Minimum 2.069 0.02 -0.01 0.148 -0.01 — — — —  Maximum 3.67 0.298 2.036 0.69 0.03 — — — —  Std. dev. 0.499 0.088 0.647 0.159 0.007 — — — — 

N obs. 17 17 17 17 17 0 0 0 0 
F-32

Table F-2. Continued.

Sampling stratum Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sod

(mg

1995 Near-surface measurements: summer

4. Lake Mean 2.834 0.051 0.364 0.67 0.071 — — — —  Median 2.587 0.021 -0.01 0.67 0.061 — — — —  Minimum 2.302 -0.02 -0.01 0.31 0.018 — — — —  Maximum 3.451 0.205 1.71 0.86 0.125 — — — —  Std. dev. 0.435 0.066 0.679 0.181 0.044 — — — — 

N obs. 8 8 8 8 8 0 0 0 0 

5. Impounded Mean 3.417 0.034 2.134 0.198 0.014 — — — —  Median 3.205 0.035 1.849 0.17 -0.01 — — — —  Minimum 2.806 -0.02 1.484 0.077 -0.01 — — — —  Maximum 4.495 0.054 3.369 0.64 0.05 — — — —  Std. dev. 0.538 0.012 0.645 0.173 0.016 — — — — 

N obs. 9 9 9 9 9 0 0 0 0 

1995 Near-surface measurements: fall

1. Main channel Mean 1.839 0.048 0.921 0.138 0.048 — — — —  Median 1.836 0.046 0.899 0.134 0.05 — — — —  Minimum 1.61 0.021 0.776 0.082 0.036 — — — —  Maximum 2.088 0.071 1.028 0.184 0.057 — — — —  Std. dev. 0.143 0.017 0.07 0.027 0.007 — — — — 

N obs. 12 12 12 12 12 0 0 0 0 

2. Side channel Mean 2.003 0.059 1.006 0.153 0.055 — — — —  Median 2.003 0.056 0.975 0.147 0.054 — — — —  Minimum 1.663 0.024 0.775 0.1 0.035 — — — —  Maximum 2.526 0.117 1.231 0.266 0.076 — — — —  Std. dev. 0.264 0.028 0.167 0.034 0.013 — — — — 

N obs. 21 21 21 21 21 0 0 0 0 

3. Backwater Mean 1.719 0.051 0.096 0.254 0.015 — — — —  Median 1.66 0.04 0.039 0.201 0.016 — — — —  Minimum 1.265 0.025 -0.01 0.122 -0.01 — — — —  Maximum 2.67 0.136 0.325 0.62 0.029 — — — —  Std. dev. 0.317 0.026 0.112 0.137 0.008 — — — — 

N obs. 17 17 17 17 17 0 0 0 0 
F-33

Table F-2. Continued.

Sampling stratum Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sod

(mg

1995 Near-surface measurements: fall

4. Lake Mean 2.588 0.036 0.105 0.363 0.014 — — — —  Median 2.514 0.034 -0.01 0.315 0.011 — — — —  Minimum 2.02 0.024 -0.01 0.239 -0.01 — — — —  Maximum 3.351 0.049 0.66 0.52 0.028 — — — —  Std. dev. 0.417 0.008 0.23 0.102 0.009 — — — — 

N obs. 8 8 8 8 8 0 0 0 0 

5. Impounded Mean 1.69 0.049 0.691 0.154 0.035 — — — —  Median 1.687 0.049 0.69 0.12 0.038 — — — —  Minimum 1.52 0.029 0.569 0.093 0.022 — — — —  Maximum 1.815 0.069 0.874 0.404 0.051 — — — —  Std. dev. 0.107 0.014 0.098 0.097 0.011 — — — — 

N obs. 9 9 9 9 9 0 0 0 0 

1996 Near-surface measurements: winter

1. Main channel Mean 3.522 0.369 2.424 0.173 0.096 — — — —  Median 3.436 0.365 2.315 0.185 0.091 — — — —  Minimum 3.162 0.292 2.136 0.101 0.059 — — — —  Maximum 4.119 0.468 2.893 0.234 0.147 — — — —  Std. dev. 0.288 0.047 0.27 0.047 0.028 — — — — 

N obs. 11 11 11 11 11 0 0 0 0 

2. Side channel Mean 3.56 0.319 2.399 0.152 0.087 — — — —  Median 3.406 0.343 2.239 0.166 0.084 — — — —  Minimum 1.85 0.059 0.445 0.056 -0.01 — — — —  Maximum 4.305 0.436 3.165 0.21 0.174 — — — —  Std. dev. 0.556 0.082 0.606 0.041 0.039 — — — — 

N obs. 20 20 20 20 20 0 0 0 0 

3. Backwater Mean 2.203 0.107 0.773 0.13 0.047 — — — —  Median 2.264 0.055 0.599 0.103 0.018 — — — —  Minimum 1.046 0.028 -0.01 0.02 -0.01 — — — —  Maximum 3.938 0.325 3.179 0.465 0.44 — — — —  Std. dev. 0.902 0.1 0.991 0.105 0.099 — — — — 

N obs. 19 19 19 19 19 0 0 0 0 
F-34

Table F-2. Continued.

Sampling stratum Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sod

(mg

1996 Near-surface measurements: winter

5. Impounded Mean 3.723 0.21 2.477 0.09 0.043 — — — —  Median 3.491 0.199 2.457 0.102 0.044 — — — —  Minimum 3.231 0.182 2.253 0.04 0.025 — — — —  Maximum 4.644 0.252 2.684 0.112 0.061 — — — —  Std. dev. 0.459 0.024 0.131 0.027 0.012 — — — — 

N obs. 8 8 8 8 8 0 0 0 0 

1996 Near-surface measurements: spring

1. Main channel Mean 2.698 — 1.519 0.286 0.064 — — — —  Median 2.533 — 1.408 0.247 0.058 — — — —  Minimum 2.244 — 1.206 0.15 0.031 — — — —  Maximum 3.625 — 2.071 0.567 0.141 — — — —  Std. dev. 0.422 — 0.254 0.111 0.029 — — — — 

N obs. 12 0 12 12 12 0 0 0 0 

2. Side channel Mean 2.916 — 1.799 0.266 0.056 — — — —  Median 2.57 — 1.424 0.234 0.047 — — — —  Minimum 2.211 — 1.202 0.178 0.029 — — — —  Maximum 6.133 — 8.562 0.463 0.144 — — — —  Std. dev. 0.912 — 1.538 0.08 0.026 — — — — 

N obs. 22 0 22 22 22 0 0 0 0 

3. Backwater Mean 2.667 — 1.441 0.351 0.052 — — — —  Median 2.676 — 0.991 0.366 0.048 — — — —  Minimum 1.035 — -0.01 0.132 0.023 — — — —  Maximum 3.68 — 6.957 0.62 0.079 — — — —  Std. dev. 0.735 — 1.667 0.153 0.017 — — — — 

N obs. 16 0 16 16 16 0 0 0 0 

4. Lake Mean 3.566 — 2.792 0.365 0.1 — — — —  Median 3.153 — 1.824 0.334 0.098 — — — —  Minimum 2.321 — 0.243 0.195 0.037 — — — —  Maximum 4.845 — 6.647 0.76 0.202 — — — —  Std. dev. 1.017 — 2.037 0.172 0.053 — — — — 

N obs. 8 0 8 8 8 0 0 0 0 
F-35

Table F-2. Continued.

Sampling stratum Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sod

(mg

1996 Near-surface measurements: spring

5. Impounded Mean 2.469 — 1.782 0.2 0.046 — — — —  Median 2.297 — 1.398 0.164 0.041 — — — —  Minimum 2.175 — 1.206 0.126 0.029 — — — —  Maximum 3.459 — 4.366 0.47 0.079 — — — —  Std. dev. 0.423 — 1.067 0.111 0.015 — — — — 

N obs. 8 0 8 8 8 0 0 0 0 

1996 Near-surface measurements: summer

1. Main channel Mean 4.549 0.01 3.581 0.276 0.056 — — — —  Median 4.256 -0.02 3.59 0.276 0.068 — — — —  Minimum 3.854 -0.02 3.102 0.276 0.026 — — — —  Maximum 7.944 -0.02 4.189 0.276 0.094 — — — —  Std. dev. 1.161 0 0.353 — 0.025 — — — — 

N obs. 11 11 11 1 11 0 0 0 0 

2. Side channel Mean 4.366 0.011 3.549 0.233 0.052 — — — —  Median 4.337 -0.02 3.59 0.23 0.057 — — — —  Minimum 3.789 -0.02 3.048 0.23 0.022 — — — —  Maximum 6.023 0.024 4.046 0.236 0.085 — — — —  Std. dev. 0.553 0.004 0.261 0.004 0.019 — — — — 

N obs. 23 23 23 2 23 0 0 0 0 

3. Backwater Mean 3.118 0.155 0.879 — 0.02 — — — —  Median 3.077 0.067 0.548 — 0.019 — — — —  Minimum 1.967 -0.02 -0.01 — -0.01 — — — —  Maximum 4.416 0.469 3.194 — 0.048 — — — —  Std. dev. 0.635 0.178 1.045 — 0.013 — — — — 

N obs. 16 16 16 0 16 0 0 0 0 

4. Lake Mean 2.181 0.025 0.257 — 0.049 — — — —  Median 2.02 -0.02 -0.01 — 0.042 — — — —  Minimum 1.842 -0.02 -0.01 — 0.014 — — — —  Maximum 2.845 0.06 0.96 — 0.1 — — — —  Std. dev. 0.331 0.022 0.411 — 0.033 — — — — 

N obs. 8 8 8 0 8 0 0 0 0 
F-36

Table F-2. Continued.

Sampling stratum Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphorus

(P mg/L)

Soluble

reactive P

 (P mg/L)

Silica

 (Si mg/L)

Calcium

(mg/L)

Magnesium

(mg/L)

Potassium

(mg/L)

Sod

(mg

1996 Near-surface measurements: summer

5. Impounded Mean 3.996 0.017 3.041 — 0.023 — — — —  Median 4.116 -0.02 3.237 — 0.016 — — — —  Minimum 2.954 -0.02 0.572 — -0.01 — — — —  Maximum 4.447 0.039 4.07 — 0.053 — — — —  Std. dev. 0.494 0.011 1.049 — 0.019 — — — — 

N obs. 8 8 8 0 8 0 0 0 0 

1996 Near-surface measurements: fall

1. Main channel Mean 2.097 0.03 0.93 — 0.045 — — — —  Median 1.724 0.035 0.913 — 0.045 — — — —  Minimum 1.413 -0.02 0.8 — 0.027 — — — —  Maximum 4.272 0.043 1.116 — 0.069 — — — —  Std. dev. 0.927 0.011 0.109 — 0.014 — — — — 

N obs. 11 11 11 0 11 0 0 0 0 

2. Side channel Mean 1.685 0.033 0.914 — 0.034 — — — —  Median 1.527 0.031 0.838 — 0.029 — — — —  Minimum 1.303 -0.02 0.61 — 0.014 — — — —  Maximum 2.294 0.072 1.299 — 0.074 — — — —  Std. dev. 0.312 0.015 0.178 — 0.015 — — — — 

N obs. 22 22 22 0 22 0 0 0 0 

3. Backwater Mean 1.446 0.028 0.256 — 0.015 — — — —  Median 1.424 -0.02 0.103 — -0.01 — — — —  Minimum 1.038 -0.02 -0.01 — -0.01 — — — —  Maximum 2.179 0.111 0.816 — 0.082 — — — —  Std. dev. 0.344 0.03 0.29 — 0.02 — — — — 

N obs. 15 16 16 0 16 0 0 0 0 

5. Impounded Mean 1.501 0.036 0.704 — 0.02 — — — —  Median 1.492 0.042 0.69 — 0.017 — — — —  Minimum 1.39 -0.02 0.609 — -0.01 — — — —  Maximum 1.59 0.062 0.829 — 0.038 — — — —  Std. dev. 0.067 0.023 0.067 — 0.011 — — — — 

N obs. 8 8 8 0 8 0 0 0 0 
F-37

Figure F-1. Water temperature (°C) in stratified random sampling episodes from spring 1993 (Sp93) through fall 1996.

Each sampling stratum is plotted separately. A solid line connects the medians of each episode, the 90th and 10th

percentiles of the data are shown by the upper and lower extent of the box, and vertical lines extend to the maximum

and minimum values (or to the limits of the plotting axis).
F-38

Figure F-2. Dissolved oxygen (mg/L) in stratified random sampling episodes from spring 1993 (Sp93) through fall 1996.

Each sampling stratum is plotted separately. A solid line connects the medians of each episode, the 90th and 10th

percentiles of the data are shown by the upper and lower extent of the box, and vertical lines extend to the maximum

and minimum values (or to the limits of the plotting axis).
F-39

Figure F-3. Dissolved oxygen saturation (%) in stratified random sampling episodes from spring 1993 (Sp93) through

fall 1996. Each sampling stratum is plotted separately. A solid line connects the medians of each episode, the 90th and

10th percentiles of the data are shown by the upper and lower extent of the box, and vertical lines extend to the maximum

and minimum values (or to the limits of the plotting axis).
F-40

Figure F-4. Specfic conductivity (:S) in stratified random sampling episodes from spring 1993 (Sp93) through fall 1996.

Each sampling stratum is plotted separately. A solid line connects the medians of each episode, the 90th and 10th

percentiles of the data are shown by the upper and lower extent of the box, and vertical lines extend to the maximum

and minimum values (or to the limits of the plotting axis).
F-41

Figure F-5. Secchi transparency (cm) in stratified random sampling episodes from spring 1993 (Sp93) through fall 1996.

Each sampling stratum is plotted separately. A solid line connects the medians of each episode, the 90th and 10th

percentiles of the data are shown by the upper and lower extent of the box, and vertical lines extend to the maximum

and minimum values (or to the limits of the plotting axis).
F-42

Figure F-6. Turbidity (NTU) in stratified random sampling episodes from spring 1993 (Sp93) through fall 1996. Each

sampling stratum is plotted separately. A solid line connects the medians of each episode, the 90th and 10th percentiles

of the data are shown by the upper and lower extent of the box, and vertical lines extend to the maximum and minimum

values (or to the limits of the plotting axis).
F-43

Figure F-7. Total suspended solids (mg/L) in stratified random sampling episodes from spring 1993 (Sp93) through fall

1996. Each sampling stratum is plotted separately. A solid line connects the medians of each episode, the 90th and 10th

percentiles of the data are shown by the upper and lower extent of the box, and vertical lines extend to the maximum

and minimum values (or to the limits of the plotting axis).
F-44

Figure F-8. Total nitrogen (mg/L) in stratified random sampling episodes from spring 1993 (Sp93) through fall 1996. Each

sampling stratum is plotted separately. A solid line connects the medians of each episode, the 90th and 10th percentiles

of the data are shown by the upper and lower extent of the box, and vertical lines extend to the maximum and minimum

values (or to the limits of the plotting axis).
F-45

Figure F-9. Nitrate–nitrite nitrogen (mg/L) in stratified random sampling episodes from spring 1993 (Sp93) through fall

1996. Each sampling stratum is plotted separately. A solid line connects the medians of each episode, the 90th and 10th

percentiles of the data are shown by the upper and lower extent of the box, and vertical lines extend to the maximum

and minimum values (or to the limits of the plotting axis).
F-46

Figure F-10. Ammonium nitrogen (mg/L) in stratified random sampling episodes from spring 1993 (Sp93) through fall

1996. Each sampling stratum is plotted separately. A solid line connects the medians of each episode, the 90th and 10th

percentiles of the data are shown by the upper and lower extent of the box, and vertical lines extend to the maximum

and minimum values (or to the limits of the plotting axis).
F-47

Figure F-11. Total phosphorus (mg/L) in stratified random sampling episodes from spring 1993 (Sp93) through fall 1996.

Each sampling stratum is plotted separately. A solid line connects the medians of each episode, the 90th and 10th

percentiles of the data are shown by the upper and lower extent of the box, and vertical lines extend to the maximum

and minimum values (or to the limits of the plotting axis).
F-48

Figure F-12. Soluble reactive phosphorus (mg/L) in stratified random sampling episodes from spring 1993 (Sp93)

through fall 1996. Each sampling stratum is plotted separately. A solid line connects the medians of each episode, the

90th and 10th percentiles of the data are shown by the upper and lower extent of the box, and vertical lines extend to

the maximum and minimum values (or to the limits of the plotting axis).
F-49

Figure F-13. Fluorometric chlorophyll a (:g/L) in stratified random sampling episodes from spring 1993 (Sp93) through

fall 1996. Each sampling stratum is plotted separately. A solid line connects the medians of each episode, the 90th and

10th percentiles of the data are shown by the upper and lower extent of the box, and vertical lines extend to the maximum

and minimum values (or to the limits of the plotting axis).
REPORT DOCUMENTATION PAGE Form Approved

OMB No. 0704-0188

Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data

sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other

aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and

Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188),

Washington, D.C. 20503

1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE

October 2002

3. REPORT TYPE AND DATES COVERED

4. TITLE AND SUBTITLE

 Limnological monitoring on the Upper Mississippi River System, 1993–1996: Long Term Resource Monitoring Program

Pool 26 Field Station

5. FUNDING NUMBERS

6. AUTHOR(S)

David M. Soballe,1

 Eric Ratcliff,2 Brad Kerans,2 and Tim Mihuc2

7. PERFORMING ORGANIZATION NAME AND ADDRESS

1

U.S. Geological Survey, Upper Midwest Environmental Sciences Center, 2630 Fanta Reed Road, La Crosse, Wisconsin 54603;

2

Illinois Natural History Survey, Illinois Department of Natural Resources, 8450 Monclair, Brighton, Illinois 62012

8. PERFORMING ORGANIZATION

 REPORT NUMBER

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)

U.S. Geological Survey

Upper Midwest Environmental Sciences Center

2630 Fanta Reed Road

La Crosse, Wisconsin 54603

10. SPONSORING/MONITORING

 AGENCY REPORT NUMBER

2002-P002

11. SUPPLEMENTARY NOTES

12a. DISTRIBUTION/AVAILABILITY STATEMENT

Release unlimited. Available from National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161

(1-800-553-6847 or 703-487-4650. Available to registered users from the Defense Technical Information Center, Attn: Help

Desk, 8725 Kingman Road, Suite 0944, Fort Belvoir, VA 22060-6218 (1-800-225-3842 or 703-767-9050).

12b. DISTRIBUTION CODE

13. ABSTRACT (Maximum 200 words)

Since 1988, the Long Term Resource Monitoring Program (LTRMP) staff have performed basic limnological field measurements in the Upper Mississippi River System. The

period of this report (1993–96) includes a major revision of the LTRMP sampling design in 1993 that added randomization, broader spatial coverage, and increased

monitoring of tributaries and locations that allow monitoring of material transport. The 1993–96 water quality data for the Pool 26 area show long-term declines in the

concentrations of total nitrogen, nitrate–nitrite nitrogen, and soluble reactive phosphorus after the large flood in 1993. The data also indicate that contiguous backwaters have

unique water quality among the sampling strata, characterized by higher turbidity, volatile suspended solids, and fluorometric chlorophyll a, and lower total nitrogen and

nitrate–nitrite nitrogen. 

The Missouri and Illinois Rivers significantly alter the Mississippi River main stem in the Pool 26 study area. The Missouri River contributes high turbidity, silicate silica, and

total suspended solids, whereas the Illinois River contributes elevated concentrations of total nitrogen, nitrate, total phosphorus, and soluble reactive phosphorus. Dissolved

oxygen concentrations (>5 mg/L) were good in the Mississippi River main stem but were somewhat lower in the Missouri and Illinois Rivers. In the Illinois River,

concentrations fell to or below the Illinois general use water quality standard of 5 mg/L every summer during 1993–96.

14. SUBJECT TERMS

Annual report, limnology, LTRMP, Mississippi River, water quality 

15. NUMBER OF PAGES

18 pp. + Appendixes A–F

16. PRICE CODE

17. SECURITY CLASSIFICATION

 OF REPORT

Unclassified

18. SECURITY CLASSIFICATION

 OF THIS PAGE

Unclassified

19. SECURITY CLASSIFICATION

 OF ABSTRACT

Unclassified

20. LIMITATION OF ABSTRACT
The Long Term Resource Monitoring Program (LTRMP) for the Upper Mississippi

River System was authorized under the Water Resources Development Act of 1986 as 

an element of the Environmental Management Program. The mission of the LTRMP

is to provide river managers with information for maintaining the Upper Mississippi 

River System as a sustainable large river ecosystem given its multiple-use character.

The LTRMP is a cooperative effort by the U.S. Geological Survey, the U.S. Army Corps

of Engineers, and the States of Illinois, Iowa, Minnesota, Missouri, and Wisconsin.