Long Term Resource Monitoring Program

Program Report

2002-P003

Limnological Monitoring on the

Upper Mississippi River System, 1993–1996:

 Long Term Resource Monitoring Program

 Onalaska 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

Onalaska Field Station

by

David M. Soballe, James R. Fischer, 

Lisa A. Hodge-Richardson, and Troy L. Clemment

October 2002

U.S. Geological Survey

Upper Midwest Environmental Sciences Center

2630 Fanta Reed Road

La Crosse, Wisconsin 54603
Suggested citation:

Soballe, D. M., J. R. Fischer, L. A. Hodge-Richardson, and T. L. Clemment. 2002. Limnological monitoring on the Upper

Mississippi River System, 1993–1996: Long Term Resource Monitoring Program Onalaska Field Station. U.S. Geological

Survey, Upper Midwest Environmental Sciences Center, La Crosse, Wisconsin, October 2002. LTRMP 2002-P003.

20 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Sample Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Laboratory Analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Quality Assurance and Quality Control Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

River Discharge Regime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

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

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

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

Stratified Random Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Sample Collection and Field Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Stratified Random Sampling Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Summary and Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

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 . . 8

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 3. Water elevation (meters above mean sea level) at Lock and Dam 7 Tailwater 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 by the Onalaska (Wisconsin) Field Station from 1993 to 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.
1

Present address: Department of Natural Resources, 820 Industrial Drive, Suite 2, Sparta, Wisconsin 54656.

2

Present address: Department of Natural Resources, 910 Highway 54 East, Black River Falls, Wisconsin 54615.

Limnological Monitoring on the

Upper Mississippi River System, 1993–1996:

Long Term Resource Monitoring Program

Onalaska Field Station

by

David M. Soballe

U.S. Geological Survey

Upper Midwest Environmental Sciences Center

2630 Fanta Reed Road

La Crosse, Wisconsin 54603

 James R. Fischer, Lisa A. Hodge-Richardson,1 and Troy L. Clemment2

Wisconsin Department of Natural Resources

LTRMP Onalaska Field Station

575 Lester Avenue

Onalaska, Wisconsin 54650

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.

Personnel from the LTRMP Onalaska (Wisconsin) Field Station made about 1,300 visits to fixed limnological

sampling sites and 2,100 visits to stratified random sites in the vicinity of Navigation Pool 8 from 1993 through

1996. An extended, late-season flood in summer 1993 coincided with some of the highest nutrient and lowest

dissolved oxygen (DO) concentrations recorded during the report period. Decreases in nutrient concentrations

(particularly nitrogen) and increases in water clarity occurred over the 4-year period. Midday DO concentrations

were above 5 mg/L throughout most of the year and across most of Pool 8, with localized exceptions during

periods of snow cover. Pool 8 and its watershed are a net source of sediment to the Mississippi River; main

channel suspended solids concentrations were greater downstream than upstream, and concentrations in the

tributaries were typically higher than in the main channel. Strong seasonal patterns were evident for temperature,

DO, Secchi transparency, turbidity, total and volatile suspended solids, silicate, chlorophyll a, and total

phosphorus. Spatial variability (among strata) of most measurements generally increased during lower discharge.

Within the individual strata, the pattern of variability could be generalized as follows: isolated backwater >

contiguous backwater > impounded > side channel > main channel.

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. 
2

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

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 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 Wisconsin 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.
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.

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). 
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.
5

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

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 1.6 km (1 mile) farther

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

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 Dam was placed in service.
6

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 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 field 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; 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).

The Wisconsin Department of Natural Resources (WDNR) field station is located at the UMESC in

Onalaska, Wisconsin. Field station staff conduct LTRMP monitoring within Pool 8, as well as adjacent

portions of the River and its tributaries (Figure A-1, Table A-1). Water quality monitoring has been

conducted in the Pool 8 vicinity by the WDNR field office staff since 1988 (Appendixes A and B).

The Pool and its tributary watersheds lie within the driftless—or unglaciated—area, referred to locally

as the Coulee Region. It is defined by Lock and Dam 8 at Mississippi River mile 679.2 and Lock and Dam
7

7 at Mississippi River mile 702.5, is about 37 km (23.3 miles) long, and is oriented roughly north–south. It

has complex braid-anastomosed channel morphometry with extensive off-channel aquatic areas that provide

diverse habitat for both aquatic and terrestrial biota, as well as numerous recreational opportunities.

The La Crosse, Wisconsin, metropolitan area, with a population of about 120,000, lies in direct proximity

to the upper third of Pool 8. Urban development, stormwater runoff, and sewage treatment effluent probably

affect habitat and water quality in Pool 8. In addition to storm sewers, there are many other point source

discharges that empty either directly or indirectly into Pool 8, including about 15 industrial dischargers and

five municipal wastewater treatment plants. The city of La Crosse operates two wastewater treatment plants

that discharge directly to the Mississippi River at about river miles 696.8 and 697.8. Two wastewater

treatment plants discharge to isolated backwaters of Pool 8. The La Crescent, Minnesota, wastewater

treatment plant discharges to Blue Lake (river miles 698–699), and Stoddard, Wisconsin, wastewater

treatment plant discharges to a small isolated backwater near the confluence of Coon Creek (river mile

684.5). At normal water elevations, these isolated backwaters have little or no connection to the main channel

of Pool 8. The fifth wastewater treatment plant at Genoa, Wisconsin, has the lowest design flow and

discharges to the main channel at river mile 679.7.

Two tributaries, the Root and La Crosse Rivers, enter the Mississippi River at river miles 693.7 and 698.2,

respectively. The Root River flows through southeastern Minnesota, an area of intense agricultural activity.

After storms and spring runoff, marked turbidity differences are often apparent between the Root River

inflow and the Mississippi River for several miles downstream. The La Crosse River transitions from a trout

stream in its upper portions to a watershed containing agriculture, swamps, marsh, and bogs in the middle

and lower portions. Problems with high sediment concentrations, low dissolved oxygen (DO), and high

ammonia concentrations have been documented in the La Crosse River, resulting in a strong recommendation

for selection as a Wisconsin Priority Watershed (WDNR 1994). Both the Root and La Crosse Rivers are

monitored at their confluence with the Mississippi River by personnel of the Onalaska (Wisconsin) Field

Station.

The Onalaska Field Station Water Quality team also monitors the main stem of the Black River at Lytle’s

Landing (before it enters Lake Onalaska) and the old Black River channel 1.6 km (1 mile) upstream of the

confluence with Pool 8. Although it is still identified as the Black River, the old Black River channel became

part of the impoundment after the Locks and Dams were established. It flows through Lake Onalaska in

Pool 7, over a spillway at Onalaska (about river mile 703.5), and enters Pool 8 at river mile 699. Although

the water entering Pool 8 retains much of its original character, it mixes somewhat with the Mississippi River

in Lake Onalaska and differs slightly from the Black River proper. Land cover in the Black River watershed

is primarily woodland (52%), followed by cropland (31%), grassland (12%), miscellaneous (4%), and

urban (<1%). The upper and central portion of the watershed is glacial deposit, with soils ranging from silty

loam in the north to sandy in the central portion. The lower portion of the watershed is unglaciated with

primarily sandy soils; as of 1980. Nineteen wastewater treatment plants discharge to streams and rivers

within the Black River basin (WDNR 1980). A national Superfund site, where groundwater is air-stripped

of volatile organic compounds and discharged to the Black River, is located immediately downstream of the

Lytle’s Landing monitoring station (BK14.2M, Figure A-1). 

Several other tributaries to the Mississippi River are also monitored by the Onalaska Field Station team.

Coon Creek (Wisconsin) is sampled 1 km (0.6 miles) upstream of the confluence with the Mississippi River,

at Mississippi River mile 684.5. The Coon Creek watershed, a small tributary to Pool 8, has been

recommended as a high priority watershed project (WDNR 1994), in part because of its effect on the

Mississippi River receiving water. The Bad Axe River, a Wisconsin tributary to Pool 9, and the Upper Iowa
8

River, an Iowa tributary to Pool 9, are also routinely sampled by the Onalaska Field Station Water Quality

team.

Declines in aquatic vegetation have been documented in Pool 8, particularly Vallisneria americana in the

lower pool (Fischer and Claflin 1995), just as similar declines have been documented in other pools of the

Mississippi River (Rogers 1994). Recent changes in the aquatic vegetation communities are important to the

evaluation of water quality data because of the profound affect that macrophytes can have on temperature,

DO, pH, underwater light, and nutrients (Wetzel 1983). Although reasons for the declines are largely

unknown, physical changes in habitat (i.e., island erosion and sedimentation of backwaters) may explain

some of the losses; about 70% of the islands in Lower Pool 8 have been lost to erosion since impoundment

(unpublished UMESC geospatial data). Informal survey data collected for the LTRMP suggest that some

recovery has occurred in certain submersed vegetation communities of Pool 8 during recent years (Heidi

Langrehr, personal communication).

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

Tailwater” (TWR-O), or “Tailwater” (TW). This classification scheme was revised in 1993 when vegetation
9

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 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. This sampling schedule was formally established in

September 1993.

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). In each SRS episode, about

150 sites are randomly 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).
10

The LTRMP design for SRS requires that each day's sampling be centered on 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. This specification for sampling times was formally established in September 1993.

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, however, samples are collected for a full complement of laboratory analyses only

in a randomly selected subset (about half) of sites. Significant improvements in laboratory performance in

1997 may reduce these limitations in future years.

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

0.2 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-type 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 DO 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
11

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

the actual vertical location of the sample in reference to the free water surface. In this report, we summarize

the data by depth sampling category rather than precise vertical location, and the 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 in La Crosse, Wisconsin (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 the 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
12

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:

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 at the Lock and Dam 7 tailwater gage (Figure 3) indicate the general hydrologic regime in

the Pool 8 study area. Flood stage at this gage is 194.65 m (638.6 feet) above mean sea level. The U.S. Army

Corps of Engineers water elevation data were obtained from the UMESC (Wlosinski et al. 1995).

Water levels at this site reflected the large, spring and summer flood of 1993 and indicate that water levels

during the entire reporting period were generally above the 56-year average but were usually below flood

stage. The flood of 1993 was notable for high water levels, but more remarkable for its duration (nearly the

entire summer) in this area. Flood stage was also exceeded in spring 1994 and 1996, but not to the same

extent as in summer 1993. 

The limnological data collected in 1993–96 reflect the hydrologic conditions at the time of collection; for

example, water levels in fall were above average during 3 of these 4 years. Water levels during winter SRS

in 1996 were above normal, whereas those in winters 1994 and 1995 were about average. The spring

maximum in water level typically occurs in mid-April every year, about one week before the spring SRS,

therefore these data reflect conditions during the crest and decline of the spring flood for all years. Water

levels during the summer SRS episodes were about average (with the exception of 1993; Figure 3). Results

of the fixed-site limnological monitoring also reflect above normal water levels in most years. 
13

Figure 3. Water elevation (meters above mean sea level) at Lock and Dam 7 Tailwater 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.

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.

From 1993 through 1996, the water quality team from the Onalaska Field Station made about 1,300 site

visits to fixed sampling locations (Appendix D). During these visits, about 1,100 grab samples were collected

for chemical processing (Appendix E).
14

The number of site visits during a week of sampling was typically 11 immediately after the 1993 redesign.

Two more tributary sites (the Upper Iowa and Bad Axe Rivers) were added to the routine fixed sites in

July 1995, bringing the total to 13 (Figure D-1 and Table D-1). Before the redesign of sampling in 1993, the

number of weekly fixed-site visits varied because some sites were sampled weekly and others less frequently.

Additionally, if scheduled sites were missed, they were often sampled during off-weeks, thereby making the

number of weekly site visits inconsistent. Sites were occasionally missed because of inaccessibility

associated with time of year and unsafe conditions (e.g., unacceptable ice conditions, deep snow, extreme

cold) and, to a lesser extent, equipment malfunctions and lack of personnel. The purchase of an airboat in

1995 considerably reduced the accessibility problems (Figure D-1) that were common when the crews relied

solely on a hovercraft for winter transportation. Time and logistical constraints during SRS episodes

sometimes prevented sampling the fixed sites as scheduled, so they were often sampled while in proximity

to SRS sites (not necessarily on the same day or even the same week). Nearly all deviations shown in

Figure D-1 were due to sampling sites during an off-week, as opposed to missing them completely

(Table D-1).

The distribution of sampling across the hours of the day (Figures D-2–D-4) reflects the September 1993

change in the fixed-site sampling protocol. In the early months of 1993, sampling was conducted earlier in

the day (median = 1140 h) and showed a somewhat broad distribution. The sampling window was more

closely (and formally) defined in 1993, and subsequently the median sampling time moved later (Figure D-2)

and was more nearly centered on 1200 h. Sampling times were generally within design specifications. The

sampling window was quite broad (but within limits) and there was a tendency to sample more sites in the

afternoon. There was also a minor, but significant, linear increase in sampling time at the fixed sites

(P < 0.001) from 1993 to 1996 (about 3 minutes per year). Most of this trend is due to the initial adjustment

to the new sampling window in September 1993; after this date the increase is not statistically significant

(P = 0.09). The distribution of fixed-site sampling times across the period of record (Figure D-3) shows a

distinct seasonal pattern, with later sampling in winter.

The distribution of median sampling times for sites (Figure D-4) is parallel to that for samples

(Figure D-2). In 1993, the median sampling time varied substantially among sites (Figure D-4), and more

sites were sampled in the morning than afternoon. After noon-centered sampling was implemented in 1993,

the median site visit times in 1994 and 1995 were more tightly grouped and shifted sharply to afternoon

(Figure D-2). Reasons for the shift are unclear, and efforts were made to bring more of the sites closer to a

1200 h median. By 1996, the distribution of sample collection times had a median of 1214 h.

Fixed-site Sampling Data

Fixed-site sampling by the Onalaska Field Station 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 reveal important functional aspects of this reach of the river. For example, the data

suggest a long-term decline in the concentrations of total and nitrate–nitrite nitrogen as well as total and

soluble reactive phosphorus (Figure E-2a). When coupled with a steady to declining flow regime (Figure 3),

this suggests a significant decline in the transport of these materials in this reach during the study period;

detailed loading calculations are needed to verify this apparent trend. Overall, trends in the tributaries were

similar to those of the main channel, where declines were also observed during the study period in some

nutrient concentrations. 
15

Although some enrichment is evident, generally only minor increases occurred in some nutrient

concentrations upstream to downstream in Pool 8, and the greatest increase was generally in nitrogen

(nitrate–nitrite and total nitrogen) concentration. Although the trends were similar, the concentrations of

nitrate–nitrite in the Root River were about 1–2 mg/L higher than the main channel, and about 1–4 mg/L

higher than the La Crosse and Black Rivers. Greater concentrations in the Root River, coupled with slightly

higher nitrate–nitrite concentrations in the downstream reach of Pool 8, suggest enrichment largely from the

Root River. Conversely, there tended to be little difference in upstream–downstream total phosphorus

concentrations. Soluble reactive phosphorus (and to a lesser extent, silicate and ammonium) tended to be

lower in the downstream reach, suggesting assimilation by phytoplankton or macrophytes. The higher

concentrations of chlorophyll a and DO in the lower reach also support this hypothesis. Nitrification may

account for downstream declines in ammonium concentration.

Contrary to longitudinal nutrient concentrations, turbidity and suspended solids increased substantially

from upstream to downstream (Figures E-1a and E-2a), suggesting that this reach (and its adjacent watershed)

is a significant source of sediment. The Root River, where the mean concentration of suspended solids was

3 to 4 times that of the main channel, and turbidity was more than double in some years, is probably one

source of this material. In addition to the Root River influence, the data suggest that other tributaries may

also have an effect. For example, Coon Creek had mean turbidity levels 3 times and suspended sediment

concentrations 4 to 5 times the main channel concentration. Suspended solids concentrations in the La Crosse

River were more than double those of the main channel. Additionally, suspended solids concentrations were

much more variable in the tributaries than in the main channel, probably because of the event-driven nature

of smaller rivers. The upstream–downstream differences coupled with greater suspended solids

concentrations in the tributaries suggest that Pool 8 and its watershed are acting as a sediment source.

The fixed-site data show the strong seasonality of flow-related parameters (e.g., turbidity, Secchi

transparency, suspended solids, and total phosphorus) in Pool 8 and its tributaries (Appendix E). Lack of

allochthonous input and elimination of wind-driven resuspension probably accounted for increased

transparency in winter, when suspended solids and turbidity were lowest. Nitrate and ammonium

concentrations peaked in the tributaries in late winter and early spring (most likely associated with the spring

thaw), although the patterns in the Root River and main channel were considerably less distinct than at other

sites. Ammonium concentrations typically showed strong spring increases (with the exception of spring

1995) at all sites, followed by generally lower concentrations throughout summer. Main channel soluble

reactive phosphorus and silica concentrations were usually lowest during May–June when chlorophyll a

concentrations were high, consistent with maximal diatom growth in late spring (Figures E-2a–E-2d). Total

phosphorus concentrations were usually lowest in winter, then peaked in spring and late summer. Conversely,

silicate concentrations were lowest in early summer, then gradually increased to a peak in winter. Although

seasonal patterns for all constituents are apparent in both the main channel and the tributaries, they are

generally less distinct in the main channel.

The DO saturation is a function of water temperature and thus shows strong seasonality at all sites.

Monthly means do not reveal extremes in DO, and the LTRMP sampling schedule (centered on 1200 h) does

not give a good representation of low (expected near sunrise) or high (expected in mid- or late afternoon)

oxygen concentrations. Oxygen concentrations frequently decline after heavy rain, and some of the lowest

DO readings were recorded during 1993 flooding. Concentrations at the fixed sites were usually near

saturation on a year-round basis, with backwaters occasionally reaching supersaturated conditions. In

addition to seasonal fluctuation, DO and temperature in some backwaters of Pool 8 are strongly influenced

by changes in river elevation (Fischer et al. 1997).
16

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, the Onalaska Field Station participated in 14 SRS episodes. In these 14 episodes, the

field team visited about 2,100 sites (Appendix B) and collected about 1,800 grab samples for chemical

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

for SRS, about half of the samples (1,000) were also analyzed for nitrogen and phosphorus species.

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

of record (Table B-2). With some exceptions, 150 sites (or randomly selected alternate sites) were sampled

during an episode. Exceptions were typically due to operational problems (i.e., hazardous weather and unsafe

ice) that prohibited routine field operations. Inaccessible sites and the use of alternate sites were rare, and

usually due to low water or a natural change in the land–water features of Pool 8 (i.e., island formation).

The SRS by the Onalaska Field Station team has conformed well to the general LTRMP design. The

distribution of SRS times across the period of record (Figure D-5) showed a tendency to sample slightly later

during the winter episode because of problems (e.g., equipment malfunction and samples freezing during

field filtration) associated with cold mornings (temperatures below 0° C), and because there are generally

more hindrances to winter sampling (e.g., unsafe ice, difficult travel, shorter duration of daylight, more

equipment required, and the need to drill sampling holes in the ice). There was a minor but significant linear

increase in sampling times over the years (P < 0.05) in backwaters and impounded areas. Although the

sampling times were generally well centered on 1200 h, main channel sites tended to be sampled slightly later

than other strata whereas isolated areas were sampled earlier. Although extensive steps have been taken to

avoid sampling one strata later than another (e.g., grouping sites for a sampling day to cover as many strata

as possible, random selection of site groups, and random selection of a starting point within a site group),

the sampling protocol is being reviewed to determine whether changes can be made to improve the

distribution of sampling times across the day. It is possible that logistical problems (i.e., proximity and

concentration of sampling sites within a particular stratum) may prevent any further improvement without

a drastic (and unrealistic) reduction in sampling efficiency.

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), but 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, DO, and velocity requirements of overwintering fish), and this information is being used to

address changing relations among limnological variables over time, differences among the sampling strata,
17

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

et al. 1997).

 Although the SRS data generally showed the same patterns and trends as the fixed-site data, some of the

small-scale temporal variability was not as evident from the SRS data. As with the fixed-site data, the SRS

results (Appendix F) indicated a general decline in total and nitrate–nitrite nitrogen concentrations in all

strata except the isolated backwaters from 1993 to 1996. A slight downward trend in total phosphorus

concentrations was evident at the main channel fixed sites, but a similar tendency was not detected with the

SRS data. Rather, phosphorus and ammonium exhibited a more seasonally distinct pattern. Main channel

water clarity also increased slightly every spring and summer during the 1993–96 period, yet a similar pattern

was not evident in the backwaters.

Ammonium nitrogen peaked during the winter episodes of 1994 and 1996. Although high values of

ammonium are common in winter, and the QA/QC samples and laboratory records give no reason to doubt

these values, this peak occurred across all six LTRMP field stations simultaneously. Snow depths were

greatest in 1994 and 1996, resulting in oxygen saturations that were much lower than in 1995. Although

heavy snow and subsequently lower oxygen concentrations may have contributed to elevated ammonium,

the peaks also occurred in samples from all LTRMP field stations, including those without ice and snow

cover.

The strong seasonality in many monitored parameters is evident from the SRS data. Total suspended

solids, volatile suspended solids, and turbidity were lowest in winter, whereas higher values were typical of

other seasons. This seasonality was evident in all strata. Water clarity in Pool 8 increased considerably during

the winter, and winter turbidities of less than four nephelometric turbidity units were common. Maximal

winter levels were typical of both Secchi transparency and ammonium. 

As with the fixed-site data, soluble reactive phosphorus tended to be lower in spring and generally higher

in summer and fall. Soluble reactive phosphorus was highest in summer 1993 which corresponded to the

initial receeding phase of the 1993 flood. Given the high flows, it is likely that transport of soluble reactive

phosphorus was great during that time. It is also likely that nitrogen transport was high, as concentrations

were near or above the highest observed during the 1993–96 period. A similar peak in nitrogen occurred in

spring 1995, although discharge was not as great and, therefore, transport was probably lower.

The seasonality of DO concentration as driven by solubility was evident (Figure F-2) in 1993–96, but the

seasonality of chlorophyll a was less pronounced (Figure F-13) . Although low chlorophyll a concentrations

were common in winter, there were exceptions; substantial chlorophyll a concentrations were observed at

times beneath the ice. For example, high concentrations were recorded when snow cover was minimal in

winter 1995. Consequently, DO concentrations were also high, and supersaturated conditions prevailed for

much of the winter. In winters with heavier snowfall (i.e., 1996), DO concentrations were lower and below

saturation across all strata, particularly in backwaters. The lowest median summer chlorophyll a

concentrations occurred during the 1993 flood, presumably due to the higher velocities and lower hydraulic

residence times. Likewise, the lowest median DO concentration also occurred at the same time in all strata

except isolated backwaters, probably due to lower phytoplankton biomass, reduced primary production, and

increased oxygen demand. By contrast, chlorophyll a concentrations were highest in summers 1994 and

1995, when the river stage was near the seasonal norm. Slower water velocities and longer retention times

may have increased phytoplankton productivity during that period.

Despite near normal water levels, summer 1996 chlorophyll a concentrations were lower than those in

either 1994 or 1995. Several factors are probably involved, but it is possible that increased abundance of
18

zebra mussels (Dreissena polymorpha) in Pool 8 had an influence. Zebra mussel spatial coverage and

abundance have not been documented in Pool 8, but anecdotal information (including personal observation)

suggests that abundances have increased over the past several years. Phytoplankton removal by zebra mussels

was suggested by Sullivan and Endris (1998) as a reason for increased water clarity and lower chlorophyll

a concentrations at Lock and Dam 9 during August–September 1997. Although they did not reveal similar

increases in clarity at Lock and Dam 8 during the same period, the SRS data showed a trend toward increased

clarity in the main channel of Pool 8. Turbidity and suspended solids in the main channel in 1996 averaged

about half the mean value seen in 1993 and were the lowest reported in the 4-year period. A similar increase

in clarity was observed over the 4-year period at the main channel fixed sites. Increases in the aquatic

vegetation of Pool 8 may also be contributing to greater water clarity. 

For most measured parameters, the patterns and means were generally similar among strata, but variability

within strata differed. Overall, variability was lower in the main channel, side channel, and impounded strata

than either the backwater or isolated backwater strata because of higher velocities and more extensive mixing

in the channel and impounded strata. Variability tended to be greatest in the isolated backwater stratum,

followed by the contiguous backwater stratum. Influenced by wastewater treatment plants and little or no

direct connection to the rest of the river, the isolated backwater stratum tended to have high ammonium and

phosphorus, average total nitrogen, and low nitrate–nitrite concentrations. For many parameters, variability

was lower in strata with higher water velocities. The strata could thus be ranked in order of decreasing

variability as follows: (1) isolated backwaters, (2) contiguous backwaters, (3) impounded areas, (4) side

channels, and (5) main channel. This ranking is not definitive; variability observed in the impounded areas

overlapped that of the side channels and the variability of the side channels overlapped that observed in the

main channel.

Summary and Recommendations

 This report documents 4 years of LTRMP monitoring (1993–96) by the Onalaska Field Station Water

Quality team and provides basic graphic and tabular summaries of the collected data. The field teams

completed about 1,300 visits to fixed sampling sites and 2,100 visits to stratified random sites from 1993

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

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

The monitoring data show that this reach of the Upper Mississippi River is moderately turbid, has nearsaturated DO concentrations at most locations throughout most of the year (near midday), and has high

concentrations of plant nutrients (particularly nitrogen). The hydrograph was highlighted by the late-season

flood of 1993 that coincided with some of the highest nutrient and lowest DO concentrations recorded during

the report period. As a result, nutrient transport was probably high during 1993. After the flood in 1993,

a 4-year downward trend was observed in nitrogen, phosphorus, and suspended sediment concentrations,

while water clarity steadily increased.

The tributaries to this reach are significant sources of sediment, with maximum sediment concentrations

in Coon Creek, Root River, and La Crosse River (highest to lowest concentrations, respectively) and

maximum nitrogen concentrations at the Root and Upper Iowa Rivers. Although the Black River had the

lowest suspended sediment concentrations of all monitored tributaries, nutrient concentrations were similar

to those of other tributaries.

The data indicate that long-term trends in this reach can be detected and that seasonal change (less than

1 year) can also be detected with the present design. Small-scale (e.g., diurnal) fluctuations cannot be
19

detected with the present design, nor does the design permit evaluation of minima or maxima (e.g., DO and

temperature). To detect small-scale temporal variability and to enhance our ability to predict minima based

on noon-centered measurements, differing approaches would be required. The LTRMP water quality teams

are already equipped to make such measurements with continuous monitoring equipment, and some smallscale analyses and continuous monitoring have been completed (Fischer et al. 1997). The data presented

demonstrate the ability of the present design to detect trends on two different temporal scales; however, the

opportunity also exists to refine the scale further with minimal effort.

The water quality data from Pool 8 have proven to be valuable. They have, for example, been used for

estimating the extent of suitable winter centrarchid habitat (Soballe et al. 1997), they have indicate a potential

effect of zebra mussels, and will continue to provide insights. The design for SRS produces percentage

estimates of “suitable” habitat based on certain species-specific criteria, but it does not describe in detail

where such habitat is located within a pool. The fixed-site data provide sound information on material inputs

and exports from the study reach and help gauge the impact of the surrounding basin on biota within the

reach.

Questions regarding the spatial distribution of habitat or the mechanisms of habitat dynamics require

information beyond that obtained from monitoring; and a combination of monitoring and focused research

is required. The LTRMP water quality monitoring data will continue to provide not only a basis for the

interpretation of such research results, but will also serve as a source of questions for future research. 

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., and T. O. Claflin. 1995. Declines in aquatic vegetation in Navigation Pool No. 8, Upper

Mississippi River between 1975 and 1991. Regulated Rivers: Research and Management 11:157–165.

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)

Rogers, S. J. 1994. Preliminary evaluation of submersed macrophyte changes in the Upper Mississippi River.

Lake and Reservoir Management 10(1):35–38.
20

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.

Sullivan, J. F., and M. B. Endris. 1998. Zebra mussel-induced water quality impacts in the Mississippi River

observed during the summer of 1997. Wisconsin Department of Natural Resources, La Crosse, January

1998. 29 pp.

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.

Wetzel, R. G. 1983. Limnology. 2nd edition. Saunders College Publishing, Holt, Reinhart, and Winston, Inc.

Orlando, Florida. 767 pp.

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)

Wisconsin Department of Natural Resources (WDNR). 1980. The Black River Basin area wide water quality

management plan. Wisconsin Department of Natural Resources, West Central Region Headquarters,

Eau Claire. 87 pp.

WDNR. 1994. Bad Axe–La Crosse water quality management plan. Wisconsin Department of Natural

Resources Publication WR329-94-REV, January 1994. 79 pp.

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

BK14.2M 1 05/06/93–12/10/96 TRIB 633202 4868518 96

M702.7T 2 05/06/93–12/10/96 IMP 637731 4858536 94

M701.4I 3 11/13/91–07/07/93 BWC 639027 4856771 6

M701.1B 4 06/11/91–12/27/96 MC 637184 4856266 99

B001.0N 5 06/11/91–06/21/93 TRIB 640507 4855524 10

BK01.0M 6 06/28/93–12/26/96 TRIB 640611 4855524 92

M698.5B 7 05/07/93–05/07/93 BWI 636664 4853457 1

M698.3D 8 05/07/93–05/07/93 BWI 637038 4853101 1

LX00.1M 9 06/11/91–12/26/96 TRIB 640435 4853086 99

M698.1G 10 05/07/93–05/07/93 BWI 637410 4852776 1

M696.5D 11 08/17/88–12/27/96 BWC 638947 4850291 101

M694.7L 12 07/25/88–07/07/93 MC 641197 4848046 10

M694.0N 13 08/09/88–07/07/93 SC 642510 4847065 9

R000.1M 14 08/17/88–12/27/96 TRIB 640647 4846727 103

M692.5C 15 07/01/93–07/08/93 BWC 639855 4845860 2

M692.8P 16 07/21/88–07/07/93 BWC 641981 4844944 10

M692.8Q 17 07/21/88–07/07/93 BWC 642052 4844887 10

M686.4K 18 10/13/88–07/08/93 BWC 641015 4844362 10

M691.9B 19 07/01/93–07/01/93 BWC 639676 4843912 1

M691.7S 20 08/05/88–03/26/93 BWI 643127 4843457 3

M691.7T 21 08/05/88–03/26/93 BWI 643215 4843442 2

M691.3B 22 08/09/88–12/27/96 BWC 639442 4843204 104

M690.4A 23 07/01/93–07/08/93 BWC 639254 4841500 2

M689.2A 24 11/14/91–04/06/93 MC 639381 4839410 9

M687.8X 25 10/06/88–04/06/93 BWC 642793 4837376 9

M687.6G 26 05/17/89–07/02/93 BWC 639753 4836889 7

M686.1V 27 07/25/88–04/06/93 BWC 642600 4836515 9

M686.6J 28 07/22/88–03/30/93 MC 640620 4836021 7

CC04.6M 29 03/21/96–05/14/96 TRIB 647900 4834750 4

M684.8W 30 08/05/88–05/06/93 BWI 643275 4834212 4

CC00.6M 31 05/06/93–12/26/96 TRIB 643626 4834061 97

M685.0E 32 07/22/88–07/02/93 BWC 639859 4833364 11

M685.0D 33 07/22/88–04/06/93 BWC 639806 4833329 10

M681.3B 34 05/17/93–12/26/96 IMP 639935 4828911 93

M680.8U 35 07/22/88–03/11/93 IMP 642397 4828329 7

M679.5V 36 07/22/88–12/27/96 IMP 642609 4825913 100

BX00.4M 37 06/26/95–12/26/96 TRIB 644226 4820006 39

UI02.9M 38 06/26/95–12/26/96 TRIB 637926 4814694 39

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

B001.0N 5 06/11/91–06/21/93 TRIB 640507 4855524 10

BK01.0M 6 06/28/93–12/26/96 TRIB 640611 4855524 92

BK14.2M 1 05/06/93–12/10/96 TRIB 633202 4868518 96

BX00.4M 37 06/26/95–12/26/96 TRIB 644226 4820006 39

CC00.6M 31 05/06/93–12/26/96 TRIB 643626 4834061 97

CC04.6M 29 03/21/96–05/14/96 TRIB 647900 4834750 4

LX00.1M 9 06/11/91–12/26/96 TRIB 640435 4853086 99

M679.5V 36 07/22/88–12/27/96 IMP 642609 4825913 100

M680.8U 35 07/22/88–03/11/93 IMP 642397 4828329 7

M681.3B 34 05/17/93–12/26/96 IMP 639935 4828911 93

M684.8W 30 08/05/88–05/06/93 BWI 643275 4834212 4

M685.0D 33 07/22/88–04/06/93 BWC 639806 4833329 10

M685.0E 32 07/22/88–07/02/93 BWC 639859 4833364 11

M686.1V 27 07/25/88–04/06/93 BWC 642600 4836515 9

M686.4K 18 10/13/88–07/08/93 BWC 641015 4844362 10

M686.6J 28 07/22/88–03/30/93 MC 640620 4836021 7

M687.6G 26 05/17/89–07/02/93 BWC 639753 4836889 7

M687.8X 25 10/06/88–04/06/93 BWC 642793 4837376 9

M689.2A 24 11/14/91–04/06/93 MC 639381 4839410 9

M690.4A 23 07/01/93–07/08/93 BWC 639254 4841500 2

M691.3B 22 08/09/88–12/27/96 BWC 639442 4843204 104

M691.7S 20 08/05/88–03/26/93 BWI 643127 4843457 3

M691.7T 21 08/05/88–03/26/93 BWI 643215 4843442 2

M691.9B 19 07/01/93–07/01/93 BWC 639676 4843912 1

M692.5C 15 07/01/93–07/08/93 BWC 639855 4845860 2

M692.8P 16 07/21/88–07/07/93 BWC 641981 4844944 10

M692.8Q 17 07/21/88–07/07/93 BWC 642052 4844887 10

M694.0N 13 08/09/88–07/07/93 SC 642510 4847065 9

M694.7L 12 07/25/88–07/07/93 MC 641197 4848046 10

M696.5D 11 08/17/88–12/27/96 BWC 638947 4850291 101

M698.1G 10 05/07/93–05/07/93 BWI 637410 4852776 1

M698.3D 8 05/07/93–05/07/93 BWI 637038 4853101 1

M698.5B 7 05/07/93–05/07/93 BWI 636664 4853457 1

M701.1B 4 06/11/91–12/27/96 MC 637184 4856266 99

M701.4I 3 11/13/91–07/07/93 BWC 639027 4856771 6

M702.7T 2 05/06/93–12/10/96 IMP 637731 4858536 94

R000.1M 14 08/17/88–12/27/96 TRIB 640647 4846727 103

UI02.9M 38 06/26/95–12/26/96 TRIB 637926 4814694 39

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

M685.0D 33 07/22/88–04/06/93 BWC 639806 4833329 10

M685.0E 32 07/22/88–07/02/93 BWC 639859 4833364 11

M686.1V 27 07/25/88–04/06/93 BWC 642600 4836515 9

M686.4K 18 10/13/88–07/08/93 BWC 641015 4844362 10

M687.6G 26 05/17/89–07/02/93 BWC 639753 4836889 7

M687.8X 25 10/06/88–04/06/93 BWC 642793 4837376 9

M690.4A 23 07/01/93–07/08/93 BWC 639254 4841500 2

M691.3B 22 08/09/88–12/27/96 BWC 639442 4843204 104

M691.9B 19 07/01/93–07/01/93 BWC 639676 4843912 1

M692.5C 15 07/01/93–07/08/93 BWC 639855 4845860 2

M692.8P 16 07/21/88–07/07/93 BWC 641981 4844944 10

M692.8Q 17 07/21/88–07/07/93 BWC 642052 4844887 10

M696.5D 11 08/17/88–12/27/96 BWC 638947 4850291 101

M701.4I 3 11/13/91–07/07/93 BWC 639027 4856771 6

M684.8W 30 08/05/88–05/06/93 BWI 643275 4834212 4

M691.7S 20 08/05/88–03/26/93 BWI 643127 4843457 3

M691.7T 21 08/05/88–03/26/93 BWI 643215 4843442 2

M698.1G 10 05/07/93–05/07/93 BWI 637410 4852776 1

M698.3D 8 05/07/93–05/07/93 BWI 637038 4853101 1

M698.5B 7 05/07/93–05/07/93 BWI 636664 4853457 1

M679.5V 36 07/22/88–12/27/96 IMP 642609 4825913 100

M680.8U 35 07/22/88–03/11/93 IMP 642397 4828329 7

M681.3B 34 05/17/93–12/26/96 IMP 639935 4828911 93

M702.7T 2 05/06/93–12/10/96 IMP 637731 4858536 94

M686.6J 28 07/22/88–03/30/93 MC 640620 4836021 7

M689.2A 24 11/14/91–04/06/93 MC 639381 4839410 9

M694.7L 12 07/25/88–07/07/93 MC 641197 4848046 10

M701.1B 4 06/11/91–12/27/96 MC 637184 4856266 99

M694.0N 13 08/09/88–07/07/93 SC 642510 4847065 9

B001.0N 5 06/11/91–06/21/93 TRIB 640507 4855524 10

BK01.0M 6 06/28/93–12/26/96 TRIB 640611 4855524 92

BK14.2M 1 05/06/93–12/10/96 TRIB 633202 4868518 96

BX00.4M 37 06/26/95–12/26/96 TRIB 644226 4820006 39

CC00.6M 31 05/06/93–12/26/96 TRIB 643626 4834061 97

CC04.6M 29 03/21/96–05/14/96 TRIB 647900 4834750 4

LX00.1M 9 06/11/91–12/26/96 TRIB 640435 4853086 99

R000.1M 14 08/17/88–12/27/96 TRIB 640647 4846727 103

UI02.9M 38 06/26/95–12/26/96 TRIB 637926 4814694 39

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 Onalaska study area.
A-8

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

Onalaska 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 Onalaska Field Station. Total area of the study reach is greater than the total area included within the

sampling strata due to 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 1,256 14 314 25 8.0 17

Side channel 1,381 16 5,522 30 0.5 20

Backwater 1,767 20 7,067 60 0.8 40

Lake 0 0 0 0 0.0 0

Impounded 3,476 40 869 25 2.9 17

Isolated 124 1 31 10 32.3 7

Totalb 8,727 91 13,803 150 1.1 100

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 Onalaska 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

Summer 93 07/19/93 07/29/93 192/147 26/25 32/30 92/59 NA 29/25 13/8 

Fall 93 09/20/93 09/28/93 157/148 25/25 30/30 66/60 NA 23/23 13/10 

Winter 94 02/08/94 02/18/94 136/134 12/12 30/30 61/59 NA 24/24 9/9 

Spring 94 05/02/94 05/10/94 173/150 25/25 30/30 76/60 NA 25/25 17/10 

Summer 94 07/25/94 08/04/94 167/148 26/25 29/29 73/60 NA 25/24 14/10 

Fall 94 10/10/94 10/20/94 166/149 25/24 31/31 73/59 NA 25/25 12/10 

Winter 95 01/30/95 02/10/95 153/150 25/25 30/30 60/60 NA 25/25 13/10 

Spring 95 05/01/95 05/12/95 157/149 25/25 31/30 59/59 NA 25/25 17/10 

Summer 95 07/24/95 08/03/95 157/149 25/25 29/29 61/61 NA 25/25 17/9 

Fall 95 10/09/95 10/20/95 181/150 25/25 31/30 88/60 NA 25/25 12/10 

Winter 96 02/05/96 02/13/96 163/151 25/25 31/30 71/60 NA 25/25 11/11 

Spring 96 04/29/96 05/06/96 177/150 25/25 30/30 77/60 NA 25/25 20/10 

Summer 96 07/22/96 07/30/96 162/149 25/24 30/30 69/60 NA 25/25 13/10 

Fall 96 10/07/96 10/14/96 159/150 25/25 30/30 69/60 NA 25/25 10/10 
B-3

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

in the vicinity of the Onalaska 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)

—

Nox: 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 Si:

Automated/molybdate

June 91–Feb. 94

(0.01 mg/L)

— Mar. 94–Present

(0.01 mg/L)

S04: 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–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

UMESC = 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 Onalaska Field Station. Table entries are

keyed to numbered points on Figure D-1.

Figure

code

Begin

date

Site

visits Comment

1 01/04/93 17 Before sampling network redesign 

2 01/25/93 21 Before sampling network redesign

3 02/01//93 17 Before sampling network redesign

4 02/15/93 4 Before sampling network redesign 

5 03/01/93 17 Before sampling network redesign

6 04/12/93 4 Before sampling network redesign 

7 04/27/93 0 Before sampling network redesign 

8 07/05/93 19 1993 flood, old fixed sites sampled to obtain additional flood information 

9 09/28/93 5 Stratified random sampling (SRS) time constraint, sampled some sites off-week

when near SRS sites 

10 01/24/94 5 SRS time constraint, aborted SRS because of hazardous weather and

malfunctioning equipment

11 02/07/94 3 SRS time constraint, hovercraft malfunctions—some sampled off-week 

12 02/14/94 2 SRS time constraint, hovercraft malfunctions—some sampled off-week 

13 02/28/94 2 Hovercraft mechanical problems, sites inaccessible any other way

14 03/28/94 3 Sampled some sites during off-week, no records for explanation 

15 05/09/94 3 SRS time constraint, sampled some sites off-week when near SRS sites 

16 08/08/94 2 SRS time constraint, sampled some sites off-week when near SRS sites 

17 12/19/95 1 Equipment problems, sampled one site during off-week 

18 01/22/96 5 Sites inaccessible because of blizzard and deep snow

19 02/12/96 1 SRS, equipment problems, sampled one site during off-week 

20 04/08/96 5 Staff illness and shortage, sampled boat sites during off-week 
D-2

Figure D-1. Number of weekly fixed-site visits from January 1993 through December 1996 by the Onalaska 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: 

B001.0N Mean 0.2 2.45 0.01 100 43 50 1 10.2 11.4 100 227 7.2 112 6 5.9  Median 0.2 2.08 0 100 43 50 1 11 11.7 94 133 7.3 111 6 4.8  Minimum 0.2 1.78 0 100 33 0 0 0.1 8.1 85 101 5.9 80 3 3  Maximum 0.2 3.77 0.05 100 54 100 2 23.2 14 158 490 7.8 155 12 9.8  Std. dev. 0 0.81 0.02 0 9.18 57.7 .96 9.29 2.28 21.1 155 0.59 26.6 2.54 3.52 

N obs. 10 6 5 4 4 4 4 10 10 10 9 10 6 10 3 

BK01.0M Mean 0.2 — — 90 15 5 0 13.8 9.8 90 250 7.5 — 11 10.2  Median 0.2 — — 90 15 5 0 14.9 10 92 246 7.5 — 11 10.6  Minimum 0.2 — — 90 15 5 0 0.1 5.4 62 140 6.6 — 5 3.1  Maximum 0.2 — — 90 15 5 0 24.2 14.8 120 348 8.4 — 21 18.1  Std. dev. 0 — — — — — — 9.45 3.13 17.7 67.3 0.59 — 3.78 4.77 

N obs. 15 0 0 1 1 1 1 15 14 14 15 15 0 15 14 

BK14.2M Mean 0.2 — — — — — — 13.8 8.86 82 132 6.8 — 22 20.8  Median 0.2 — — — — — — 15.6 8.9 88 132 7 — 10 14.9  Minimum 0.2 — — — — — — 0 3.8 43 56 5.8 — 6 3.7  Maximum 0.2 — — — — — — 22.5 13.5 95 228 7.3 — 163 62.8  Std. dev. 0 — — — — — — 7.69 2.66 14.5 47.4 0.45 — 34.8 17.5 

N obs. 20 0 0 0 0 0 0 20 20 20 20 20 0 20 16 

CC00.6M Mean 0.2 — — 100 9 5 0 13.2 9.46 88 505 7.7 — 48 92.3  Median 0.2 — — 100 9 5 0 14.6 9.3 88 498 7.7 — 31 61.6  Minimum 0.2 — — 100 9 5 0 0 6.5 70 365 7.2 — 4 14.8  Maximum 0.2 — — 100 9 5 0 20.9 13.3 101 620 8.3 — 233 434  Std. dev. 0 — — — — — — 6.54 2.1 8.04 57.9 0.27 — 53.1 104 

N obs. 20 0 0 1 1 1 1 20 19 19 20 20 0 20 16 

LX00.1M Mean 0.2 2.22 0.49 95 27 50 0 12.2 10.3 92 351 7.6 55.7 24 44.7  Median 0.2 2.28 0.54 95 27 50 0 14.3 9.9 96 340 7.7 47.5 20 31.8  Minimum 0.2 1.45 0.21 95 27 50 0 0 4.7 54 194 6.4 25 4 6.2  Maximum 0.2 3.05 0.73 95 27 50 0 24.2 14.3 124 513 8.5 135 86 123  Std. dev. 0 0.58 0.17 — — — — 8.41 2.65 14.9 66.3 0.59 31.8 18.5 36.4 

N obs. 24 10 8 1 1 1 1 24 23 23 24 24 10 24 16 

M679.5V Mean 0.2 1.41 0.28 100 36 99 8 11.6 10.8 95 515 7.7 43.6 20 34.5  Median 0.2 1.3 0.28 100 36 100 6 12.5 10.6 93 528 7.7 37 20 34.2  Minimum 0.2 0.92 0.03 100 28 95 0 0 6.5 74 359 6.7 27 2 2.6  Maximum 0.2 3.8 0.73 100 45 100 17 24.8 16.5 138 616 8.5 140 42 65.8  Std. dev. 0 0.56 0.21 0 5.16 1.86 5.7 9.58 2.94 14.3 66.2 0.38 26.3 14.7 21 

N obs. 26 26 26 7 7 7 7 26 26 26 26 26 17 26 16 
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: 

M680.8U Mean 0.2 2.03 0.08 100 33 99 6 0.11 13.4 92 548 7.4 170 2 —  Median 0.2 2.03 0.08 100 34 100 3 0.1 13 89 565 7.5 166 2 —  Minimum 0.2 1.97 0.07 100 25 95 0 0 11.3 77 454 6.4 134 2 —  Maximum 0.2 2.13 0.09 100 40 100 15 0.2 16.2 111 578 7.7 208 3 —  Std. dev. 0 0.06 0.01 0 4.91 1.83 6 0.09 1.65 11.2 44.4 0.45 32.3 0.53 — 

N obs. 7 7 7 7 7 7 7 7 7 7 7 7 6 7 0 

M681.3B Mean 0.2 — — — — — — 14.4 10.9 102 514 8 37.5 23 30.9  Median 0.2 — — — — — — 15.8 10.5 104 528 8 38.5 25 35.1  Minimum 0.2 — — — — — — 0.2 6.2 73 422 7.3 27 4 2.9  Maximum 0.2 — — — — — — 25.1 17.8 136 614 8.6 46 52 70.3  Std. dev. 0 — — — — — — 8.89 3.38 17.1 46.7 0.37 9.47 14 22 

N obs. 17 0 0 0 0 0 0 17 17 17 17 17 4 16 14 

M685.0D Mean 0.2 1.55 0.11 100 33 94 6 0.83 13.9 97 528 7.5 84.4 21 —  Median 0.2 1.49 0.07 100 33 100 3 0.1 13.4 92 563 7.5 113 3 —  Minimum 0.2 1.41 0.04 100 26 50 0 0 11.9 88 327 7.1 9 3 —  Maximum 0.2 2.15 0.34 100 38 100 15 5.7 17.9 123 611 7.7 148 153 —  Std. dev. 0 0.22 0.1 0 4.02 17.6 5.6 1.82 1.77 10.8 91.3 0.22 60.7 47.2 — 

N obs. 10 10 10 8 8 8 8 10 10 10 10 10 5 10 0 

M685.0E Mean 0.2 1.15 0.09 100 37 100 7 2.68 13.4 96 511 7.5 27.3 22 30.5  Median 0.2 0.95 0.02 100 38 100 4 0.1 13.3 92 507 7.4 31 3 30.5  Minimum 0.2 0.87 0.01 100 28 98 0 0 6.2 70 330 7.1 8 2 30.5  Maximum 0.2 2.8 0.38 100 44 100 18 21.2 18.6 128 622 7.9 43 153 30.5  Std. dev. 0 0.57 0.13 0 5.94 0.76 6.9 6.38 3.15 15.4 92 0.29 17.8 45 — 

N obs. 11 11 11 7 7 7 7 11 11 11 11 11 3 11 1 

M686.1V Mean 0.2 1.24 0.08 100 33 100 5 1.14 13.3 94 463 7.3 51 6 —  Median 0.2 1.16 0.06 100 33 100 3 0.2 13.1 91 497 7.3 51 3 —  Minimum 0.2 1.12 0.05 100 23 99 0 0 12.1 83 294 6.7 48 2 —  Maximum 0.2 1.7 0.23 100 39 100 15 6.3 16.3 112 545 7.8 54 17 —  Std. dev. 0 0.2 0.06 0 5.13 0.38 5.3 2.17 1.26 9.5 98 0.42 4.24 5.59 — 

N obs. 9 9 9 7 7 7 7 9 9 9 9 8 2 9 0 

M686.4K Mean 0.2 1.13 0.18 100 38 100 7 4.89 12.9 96 502 7.5 44.7 12 34.7  Median 0.2 0.83 0.09 100 38 100 4 0.1 13.5 96 526 7.5 42 3 34.7  Minimum 0.2 0.76 0.06 100 26 99 0 0 6.5 75 388 7 40 2 25.1  Maximum 0.2 2.5 0.48 100 57 100 16 22 17.4 119 601 8 52 38 44.3  Std. dev. 0 0.6 0.16 0 9.85 0.38 6 8.63 3.44 12.7 79.7 0.35 6.43 13.7 13.6 

N obs. 11 11 11 7 7 7 7 11 11 11 11 10 3 11 2 
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: 

M686.6J Mean 0.2 1.68 0.14 100 38 100 7 0.61 13.4 94 515 7.5 132 4 —  Median 0.2 1.62 0.13 100 39 100 5 0 13.5 92 548 7.7 148 3 —  Minimum 0.2 1.52 0.11 100 32 98 0 0 12.6 86 413 6.6 77 2 —  Maximum 0.2 2.01 0.27 100 43 100 15 4 14.6 111 574 8.2 157 10 —  Std. dev. 0 0.17 0.06 0 3.66 0.82 5.4 1.49 0.63 8.23 63.5 0.58 32.9 2.79 — 

N obs. 7 7 7 6 6 6 6 7 7 7 7 6 5 7 0 

M687.6G Mean 0.2 0.64 0 100 33 100 5 4.12 9.72 75 775 7.6 38 8 13.7  Median 0.2 0.44 0 100 32 100 2 0.55 7.3 84 863 7.5 38 6 13.7  Minimum 0.2 0.4 0 100 28 99 0 0.2 1.8 12 390 7 38 3 13.7  Maximum 0.2 1.7 0 100 38 100 14 22 21 149 905 8.5 38 19 13.7  Std. dev. 0 0.52 0 0 4.36 0.45 5.9 8.77 7.83 54.9 218 0.55 — 6.3 — 

N obs. 7 6 6 5 5 5 5 6 5 5 5 5 1 5 1 

M687.8X Mean 0.2 2.45 0.16 100 34 100 7 1.12 13.5 95 463 7.4 129 6 2.3  Median 0.2 2.43 0.1 100 35 100 3 0.2 13 96 495 7.4 152 3 2.3  Minimum 0.2 2.2 0.07 100 27 100 1 0 12 82 291 6.8 43 2 2.3  Maximum 0.2 2.99 0.47 100 41 100 15 6 16.1 110 555 8.1 198 19 2.3  Std. dev. 0 0.23 0.14 0 4.76 0 6.4 2.06 1.58 11.1 102 0.39 51.9 6.05 — 

N obs. 9 9 9 7 7 7 7 9 9 9 9 8 9 9 1 

M689.2A Mean 0.2 2.26 0.28 100 22 92 6 1.21 13.1 93 535 7.4 124 13 —  Median 0.2 2.15 0.23 100 21 100 6 0.1 13.1 92 560 7.3 143 3 —  Minimum 0.2 1.81 0.18 100 16 50 0 0 11.7 87 443 6.8 28 3 —  Maximum 0.2 2.81 0.61 100 27 100 13 5.5 14.3 103 601 8.1 201 53 —  Std. dev. 0 0.35 0.14 0 3.45 18.7 4.8 2.29 0.77 5.36 61.4 0.48 60.5 18.7 — 

N obs. 9 8 9 7 7 7 7 9 8 8 9 8 9 9 0 

M691.3B Mean 0.2 1.26 0.04 99.9 31 75 5 11.9 11.4 104 480 7.7 52 15 17.8  Median 0.2 1 0 100 35 100 5 13.2 11.8 103 473 7.8 50 10 15.6  Minimum 0.2 0.8 0 99 8 0 0 0.2 5.6 61 221 6.2 19 2 0.9  Maximum 0.2 2.6 0.34 100 39 100 12 27 17.8 191 686 8.6 100 63 35.6  Std. dev. 0 0.55 0.08 0.32 8.98 42.5 4.6 9.5 3.13 31.8 124 0.6 19.8 14.9 11 

N obs. 27 27 27 10 10 10 10 27 27 27 26 26 21 27 15 

M692.8P Mean 0.2 0.87 0.27 99.7 16 93 7 3.11 13.1 95 464 7.5 49.3 8 21.6  Median 0.2 0.71 0.25 100 15 100 4 0.1 14.4 100 501 7.6 54 4 21.6  Minimum 0.2 0.47 0.13 99 9 60 0 0 6 69 311 6.9 30 3 21.6  Maximum 0.2 1.9 0.52 100 25 100 18 22.2 15.5 106 562 8.1 64 19 21.6  Std. dev. 0 0.45 0.13 0.52 5.79 16 7.7 6.91 2.78 11.6 86.7 0.4 17.5 7.13 — 

N obs. 10 10 10 6 6 6 6 10 10 10 10 10 3 10 1 
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: 

M692.8Q Mean 0.2 0.97 0.3 100 22 93 7 3.12 12.9 93 457 7.6 52.3 8 23.8  Median 0.2 0.91 0.22 100 23 100 4 0.1 13.8 96 492 7.5 52 3 23.8  Minimum 0.2 0.84 0.15 100 8 60 0 0 5.8 67 304 7.2 45 3 23.8  Maximum 0.2 1.3 0.6 100 30 100 20 22.2 15.2 106 544 8.1 60 21 23.8  Std. dev. 0 0.15 0.16 0 7.79 16 8 6.89 2.76 12 86.5 0.35 7.51 7.77 — 

N obs. 10 10 10 6 6 6 6 10 10 10 10 10 3 10 1 

M694.0N Mean 0.2 1.72 0.2 100 18 71 4 3.39 12.4 90 450 7.4 99.7 8 27.2  Median 0.2 1.6 0.11 100 19 99 2 0.1 12.7 90 468 7.4 103 4 27.2  Minimum 0.2 0.8 0.07 100 7 5 0 0 5.9 68 308 6.9 41 3 27.2  Maximum 0.2 4 0.51 100 26 100 9 22 15.3 105 534 7.9 153 22 27.2  Std. dev. 0 0.92 0.16 0 7.26 42.6 4.4 7.15 2.71 11.5 87.4 0.3 51.3 7.24 — 

N obs. 9 9 9 5 5 5 5 9 9 9 9 9 6 9 1 

M694.7L Mean 0.2 1.53 0.48 91.7 13 71 2 3.06 12.9 94 500 7.4 82.5 9 41.1  Median 0.2 0.91 0.32 100 11 88 1 0.15 13.4 93 504 7.4 63.5 3 41.1  Minimum 0.2 0.73 0.13 50 3 0 0 0 6.3 72 372 6.7 32 2 41.1  Maximum 0.2 3.6 1.1 100 35 100 4 22 15.4 108 587 8.1 171 34 41.1  Std. dev. 0 1.05 0.34 20.4 11.3 40.1 1.8 6.85 2.57 10.6 76.7 0.4 61.4 10.8 — 

N obs. 10 10 10 6 6 6 6 10 10 10 10 10 4 10 1 

M696.5D Mean 0.2 1.57 0.02 97.5 37 74 5 11.9 10.1 91 504 7.6 56.3 12 13.7  Median 0.2 1.3 0.01 100 43 100 4 13.2 10.3 91 520 7.7 55.5 11 12.9  Minimum 0.2 0.5 0 90 9 0 0 0 5.2 51 371 6.5 30 4 3.9  Maximum 0.2 3.3 0.1 100 54 100 16 25.3 15.4 160 651 8.6 77 25 24.9  Std. dev. 0 0.84 0.03 4.63 18.1 45.7 6.1 9.48 3.05 22.8 71.2 0.59 13.9 5.31 5.24 

N obs. 26 26 26 8 8 8 8 26 26 26 26 26 22 26 15 

M701.1B Mean 0.2 2.31 0.41 100 26 100 5 12.9 10.1 91 447 7.6 67.2 15 17.8  Median 0.2 2.24 0.45 100 26 100 5 15.3 10.2 90 484 7.7 55 13 15.5  Minimum 0.2 1 0.09 100 23 100 2 0 6.2 68 201 6.3 28 3 2.3  Maximum 0.2 3.5 0.74 100 28 100 7 24 14.9 121 563 8.5 175 35 43  Std. dev. 0 0.7 0.24 0 3.54 0 3.5 8.91 3.15 13 93.7 0.52 39.1 8.71 11 

N obs. 23 22 23 2 2 2 2 23 23 23 23 22 22 23 16 

M701.4I Mean 0.2 1.7 0.1 100 37 75 5 5.33 9.9 76 381 7 59.5 7 15.7  Median 0.2 0.98 0 100 38 100 6 1.1 11.2 84 430 7 59.5 5 15.7  Minimum 0.2 0.71 0 100 28 0 0 0.2 3.4 24 120 6.4 50 3 15.7  Maximum 0.2 4.2 0.46 100 44 100 8 22.2 14.5 102 526 7.6 69 15 15.7  Std. dev. 0 1.42 0.19 0 6.9 49.8 3.6 8.63 4.33 27.5 161 0.46 13.4 4.68 — 

N obs. 6 6 6 4 4 4 4 6 6 6 5 6 2 6 1 
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: 

M702.7T Mean 0.2 — — 93.3 6 25 1 14.5 9.65 90 333 7.5 — 14 15.4  Median 0.2 — — 90 5 5 1 16.7 9.4 94 367 7.5 — 12 11.4  Minimum 0.2 — — 90 2 0 0 0.3 5.6 61 42 5.9 — 4 3.1  Maximum 0.2 — — 100 10 70 1 24.1 16.3 112 577 8.3 — 38 52  Std. dev. 0 — — 5.77 4.04 39.1 .71 8.31 3.14 13.6 155 0.62 — 8.75 13.5 

N obs. 20 0 0 3 3 3 2 20 19 19 20 20 0 20 16 

R000.1M Mean 0.2 1.56 0.7 87.6 30 95 2 10.1 10.5 89 550 7.8 47.2 38 62.1  Median 0.2 1.4 0.72 95 31 99 0 10.9 10.6 93 580 7.8 40 20 37.8  Minimum 0.2 0.7 0.26 50 16 80 0 0 5.2 59 255 6.7 8 5 13.9  Maximum 0.2 3.3 1.1 99 46 100 10 21.9 13.8 107 648 8.7 111 175 229  Std. dev. 0 0.66 0.18 21.1 12.6 8.38 4.4 7.93 2.61 11.6 87.9 0.5 27.6 42.6 58.9 

N obs. 28 28 24 5 5 5 5 28 28 28 28 28 21 28 17 

1993 Near-bottom measurements: 

M691.3B Mean 0.98 1.18 — — — — — 15.6 10.8 106 421 8.2 — 16 —  Median 1 1.2 — — — — — 14.4 10.5 116 421 8.2 — 16 —  Minimum 0.6 0.8 — — — — — 3 3.5 42 421 8.2 — 16 —  Maximum 1.3 1.5 — — — — — 24.8 17 171 421 8.2 — 16 —  Std. dev. 0.24 0.25 — — — — — 8.21 4 38.8 — — — — — 

N obs. 9 9 0 — — — — 9 9 9 1 1 — 1 0 

M696.5D Mean 1.37 1.56 0.01 — — — — 16.2 8.05 78 472 7.7 — 9 —  Median 1.3 1.48 0.01 — — — — 16.2 6.2 74 472 7.7 — 9 —  Minimum 1 1.2 0 — — — — 3.5 4.4 43 454 7.1 — 9 —  Maximum 1.8 2.02 0.02 — — — — 24.3 14.3 108 490 8.4 — 9 —  Std. dev. 0.37 0.37 0.01 — — — — 7.86 3.89 25.9 25.5 0.93 — — — 

N obs. 6 6 2 — — — — 6 6 6 2 2 — 1 0 

1994 Near-surface measurements: 

BK01.0M Mean 0.2 — — 93.8 18 74 5 12.2 10.7 100 287 7.8 108 8 9.1  Median 0.2 — — 97.5 22 98 5 11.8 10.8 94 281 7.9 108 6 7.9  Minimum 0.2 — — 80 4 0 0 0 7 63 117 6.1 96 4 1.1  Maximum 0.2 — — 100 26 100 10 25.2 14.7 164 482 9 120 22 20.9  Std. dev. 0 — — 9.46 9.81 49.2 4.2 9.55 2.07 23.3 90 0.75 17 4.9 5.89 

N obs. 26 0 0 4 4 4 4 26 25 25 26 26 2 25 25 
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)

1994 Near-surface measurements: 

BK14.2M Mean 0.2 — — 99 4 99 5 11.3 10.4 97 158 7.4 — 16 18.4  Median 0.2 — — 99 4 99 5 12.3 10.4 93 159 7.5 — 13 14.9  Minimum 0.2 — — 99 1 99 5 0 5.8 67 71 6.1 — 5 3.4  Maximum 0.2 — — 99 7 99 5 25.1 13.4 139 263 8.9 — 58 75.6  Std. dev. 0 — — 0 4.24 0 — 9.16 1.91 15.7 38.8 0.67 — 11.8 16 

N obs. 26 0 0 2 2 2 1 26 23 23 26 26 0 26 25 

CC00.6M Mean 0.2 1.63 — 98.3 30 97 9 10.4 10.4 92 513 7.9 47 26 66.8  Median 0.2 1.6 — 100 33 100 8 12.2 9.8 92 512 8 50 24 63  Minimum 0.2 1.5 — 95 10 90 1 -0.2 8 80 469 6.4 40 8 11.1  Maximum 0.2 1.8 — 100 47 100 18 22.1 15.2 104 627 8.3 51 70 207  Std. dev. 0 0.13 — 2.89 18.7 5.77 8.5 7.26 1.85 5.13 36.8 0.41 6.08 16 48 

N obs. 26 4 0 3 3 3 3 26 25 25 25 26 3 26 25 

LX00.1M Mean 0.2 1.6 0.55 100 28 100 2 12.1 10.8 101 342 7.9 89.5 26 52.7  Median 0.2 1.6 0.55 100 28 100 2 12.7 11 94 339 8 89.5 25 59.9  Minimum 0.2 1.4 0.55 100 28 100 2 0 7.5 72 280 6.4 49 5 6.5  Maximum 0.2 1.8 0.55 100 28 100 2 25.9 13.5 141 423 8.7 130 58 132  Std. dev. 0 0.28 — — — — — 8.53 1.68 18.7 32 0.59 57.3 13.9 32.6 

N obs. 24 2 1 1 1 1 1 24 23 23 24 24 2 23 23 

M679.5V Mean 0.2 1.45 0.18 98.3 19 65 7 14.2 11.2 108 444 8.2 50 21 29.8  Median 0.2 1.34 0.19 100 15 95 6 14.9 10.8 108 440 8.3 48.5 20 31.3  Minimum 0.2 0.68 0.03 95 11 0 0 -0.1 4.6 33 388 7.3 29 2 1  Maximum 0.2 2.53 0.39 100 32 100 16 25.7 16.4 153 527 9 85 43 67.8  Std. dev. 0 0.51 0.1 2.89 11.2 56.3 8.1 9.09 2.79 25.3 37.2 0.41 15.3 11 19.4 

N obs. 22 22 22 3 3 3 3 22 22 22 21 22 20 21 21 

M681.3B Mean 0.2 0.85 — 100 5 100 3 12.4 11.3 105 450 8.1 — 23 30.8  Median 0.2 0.85 — 100 5 100 3 14.2 10.9 100 446 8.2 — 21 25  Minimum 0.2 0.7 — 100 5 100 3 0 6.3 69 295 6.8 — 2 1.4  Maximum 0.2 1 — 100 5 100 3 25.7 16 156 623 8.9 — 83 93  Std. dev. 0 0.21 — — — — — 9.61 2.4 21.8 60.9 0.53 — 18.8 24.2 

N obs. 25 2 0 1 1 1 1 25 24 24 23 25 0 25 24 

M691.3B Mean 0.2 0.88 0.01 100 23 48 1 14.2 11.8 115 395 8.2 53.4 14 17.7  Median 0.2 0.79 0 100 19 50 1 14.9 10.7 108 373 8.4 50.5 12 15.7  Minimum 0.2 0.55 0 100 4 0 0 0.1 1.1 8 268 6.6 35 2 1.4  Maximum 0.2 1.56 0.04 100 41 100 5 26.5 21.2 198 771 9.4 98 35 43.9  Std. dev. 0 0.25 0.01 0 15.6 47.6 2.1 9.38 4.59 42.5 103 0.68 15.7 7.91 11.8 

N obs. 23 22 22 5 5 5 5 23 23 23 23 23 16 23 22 
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: 

M696.5D Mean 0.2 1.03 0.01 97.5 28 42 4 13.3 10.9 103 462 8 51.7 19 22.5  Median 0.2 1 0 100 26 25 0 14.5 10.8 94 459 7.9 51 17 18.3  Minimum 0.2 0.32 0 85 3 0 0 0 5.8 49 363 6.9 26 3 2.4  Maximum 0.2 1.5 0.04 100 53 100 12 26 20 172 573 9 100 61 77.3  Std. dev. 0 0.31 0.01 6.12 18.2 46.7 5.5 9.84 3.2 31.2 49.4 0.5 20.2 13 17.5 

N obs. 23 23 23 6 6 6 6 23 23 23 23 23 20 22 22 

M701.1B Mean 0.2 2.03 0.27 97.5 18 98 7 12.6 10.7 98 413 8 64.9 15 18.2  Median 0.2 1.87 0.25 97.5 18 98 7 13.1 10.6 93 409 8.1 61 13 15.5  Minimum 0.2 0.9 0.12 95 13 95 2 0 6.5 71 311 6.9 25 3 1.4  Maximum 0.2 3.4 0.53 100 22 100 11 24.7 16.3 133 583 8.7 165 37 45.9  Std. dev. 0 0.62 0.11 3.54 6.36 3.54 6.4 9.25 2.75 16.9 64.5 0.49 32 8.15 12.4 

N obs. 24 24 23 2 2 2 2 24 24 24 24 24 24 24 23 

M702.7T Mean 0.2 0.97 0.04 98 28 44 5 12.5 10.8 100 311 7.8 85.7 10 20.6  Median 0.2 1 0.04 100 34 20 2 13.8 10.2 93 303 7.9 66 9 10.6  Minimum 0.2 0.7 0.04 90 3 0 0 0 5.9 70 136 6.3 61 2 0.7  Maximum 0.2 1.2 0.04 100 44 100 12 24.1 17.8 212 565 9 130 28 237  Std. dev. 0 0.25 — 4.47 15.6 51.8 5.8 9.48 2.95 30.2 118 0.67 38.5 6.08 47.6 

N obs. 24 3 1 5 5 5 5 24 23 23 23 24 3 24 23 

R000.1M Mean 0.2 1.32 0.68 95 58 95 8 12.5 10.5 97 537 7.9 54.6 25 60.7  Median 0.2 1.21 0.68 95 58 95 8 13.4 9.9 95 539 8.1 52.5 20 43.1  Minimum 0.2 0.72 0.54 95 58 95 8 -0.1 8.9 85 406 6.8 16 6 2.4  Maximum 0.2 2 0.81 95 58 95 8 25.8 13.7 115 644 8.4 101 120 335  Std. dev. 0 0.37 0.19 — — — — 7.98 1.48 7.42 45.8 0.4 22.6 24.2 69.1 

N obs. 23 14 2 1 1 1 1 23 23 23 23 23 12 23 22 

1994 Near-bottom measurements: 

M691.3B Mean 0.78 0.98 — — — — — 18.2 8.33 90 348 8.7 — — —  Median 0.75 0.96 — — — — — 20.6 8.55 93 348 8.7 — — —  Minimum 0.6 0.78 — — — — — 2.1 5.5 55 348 8.7 — — —  Maximum 1.1 1.3 — — — — — 24.1 10 119 348 8.7 — — —  Std. dev. 0.19 0.2 — — — — — 8.22 1.65 27.3 — — — — — 

N obs. 6 6 0 — — — — 6 6 6 1 1 — 0 0 
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-bottom measurements: 

M696.5D Mean 1 1.2 — — — — — 14.3 9.55 95 449 8.3 — — —  Median 1.05 1.26 — — — — — 18.9 8.9 94 449 8.3 — — —  Minimum 0.5 0.75 — — — — — 1 7.1 50 449 8.3 — — —  Maximum 1.3 1.5 — — — — — 24 12.8 134 449 8.3 — — —  Std. dev. 0.32 0.3 — — — — — 10.4 2.35 34.2 — — — — — 

N obs. 6 6 0 — — — — 6 6 6 1 1 — 0 0 

1995 Near-surface measurements: 

BK01.0M Mean 0.2 3.1 — 93 12 43 0 12.3 12.1 114 244 8.3 — 8 13.4  Median 0.2 3.1 — 100 10 40 0 10.6 12.1 94 254 8.1 — 7 7.7  Minimum 0.2 3.1 — 80 1 0 0 0.3 5.6 56 131 7 — 3 2.5  Maximum 0.2 3.1 — 100 26 100 1 29.3 25 332 393 9.6 — 17 136  Std. dev. 0 — — 9.75 9.81 37 0.5 11 4.01 55.6 82.7 0.69 — 3.61 26.2 

N obs. 26 1 0 5 5 5 4 26 26 26 26 26 0 24 24 

BK14.2M Mean 0.2 — — — — — — 11 9.96 89 143 7.6 — 11 17.1  Median 0.2 — — — — — — 9.45 10.1 87 151 7.6 — 8 13.8  Minimum 0.2 — — — — — — -0.1 3.4 40 64 6.6 — 4 2.1  Maximum 0.2 — — — — — — 29.4 12.4 126 200 8.7 — 22 44.3  Std. dev. 0 — — — — — — 10.3 1.89 19.1 40.5 0.51 — 5.57 13.6 

N obs. 26 0 0 0 0 0 0 26 26 26 26 26 0 24 25 

BX00.4M Mean 0.2 0.65 — 95 13 51 2 12.2 9.99 91 479 8.2 — 22 52.6  Median 0.2 0.65 — 95 13 51 2 12.2 10 92 480 8.3 — 19 34  Minimum 0.2 0.65 — 90 5 1 0 0 7.8 75 465 8 — 6 8.1  Maximum 0.2 0.65 — 100 21 100 4 25.8 12.5 100 505 8.4 — 50 182  Std. dev. 0 — — 7.07 11.3 70 2.8 8.76 1.66 6.79 9.46 0.13 — 13.6 49.4 

N obs. 14 1 0 2 2 2 2 14 14 14 14 14 0 12 13 

CC00.6M Mean 0.2 1.05 — 95 11 60 1 9.92 10.3 89 493 8.2 68 32 74.2  Median 0.2 1.05 — 100 10 90 0 9.95 10.2 90 496 8.2 68 18 40.8  Minimum 0.2 1.05 — 80 6 0 0 -0.1 7.8 69 469 7.8 68 7 11.7  Maximum 0.2 1.05 — 100 18 99 2 24.7 13 98 517 8.4 68 210 609  Std. dev. 0 — — 8.66 5.22 50.1 1 8.06 1.67 7.08 12 0.15 — 42.2 118 

N obs. 26 1 0 5 5 5 4 26 26 26 26 26 1 24 25 
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)

1995 Near-surface measurements: 

LX00.1M Mean 0.2 — — 100 22 80 0 11.5 11.1 100 346 8.3 — 22 41.5  Median 0.2 — — 100 22 80 0 9.7 11.6 94 345 8.3 — 23 38.1  Minimum 0.2 — — 100 22 80 0 -0.1 6.9 80 284 7.7 — 4 3.8  Maximum 0.2 — — 100 22 80 0 27.5 13.4 134 454 9.1 — 49 101  Std. dev. 0 — — — — — — 9.97 1.74 16.7 33.6 0.37 — 12.9 26.8 

N obs. 26 0 0 1 1 1 1 26 26 26 26 26 0 24 24 

M679.5V Mean 0.2 1.11 0.14 99.9 27 63 4 11.5 12.1 107 465 8.5 54.8 15 23.3  Median 0.2 0.94 0.1 100 29 95 3 9.7 11.4 102 484 8.5 49 18 25.8  Minimum 0.2 0.67 0 99 11 0 0 0 6.9 79 344 8 31 3 1.5  Maximum 0.2 2.4 0.46 100 39 100 13 28.7 20.5 155 551 9 110 31 50.1  Std. dev. 0 0.46 0.11 0.35 8.52 48.3 4.7 10.6 3.2 19 61.9 0.24 20.5 9.13 16.6 

N obs. 26 26 26 8 8 8 7 26 26 26 26 26 19 26 25 

M681.3B Mean 0.2 — — — — — — 11.8 12.1 108 464 8.4 — 18 28.1  Median 0.2 — — — — — — 9.9 11.7 103 479 8.4 — 18 25.9  Minimum 0.2 — — — — — — 0 6.5 80 336 7.9 — 3 1.8  Maximum 0.2 — — — — — — 29.7 19 149 560 8.9 — 45 78  Std. dev. 0 — — — — — — 10.8 3.03 19.6 67.5 0.22 — 13.7 23.5 

N obs. 26 0 0 0 0 0 0 26 26 26 26 26 0 24 25 

M691.3B Mean 0.19 0.92 0 100 28 77 3 12.5 12.9 116 432 8.4 49.5 15 18.8  Median 0.2 0.89 0 100 32 100 2 10.1 12.9 112 400 8.6 49.5 15 17.4  Minimum 0.1 0.57 0 100 5 1 0 0.2 6.3 49 319 7.4 30 3 2  Maximum 0.2 1.47 0.02 100 41 100 13 32.5 23.5 167 686 9.3 77 38 55.4  Std. dev. 0.03 0.21 0 0 12.3 40.7 4.1 10.7 4.52 28.8 95.6 0.45 14.7 10.9 15.1 

N obs. 26 26 26 9 9 9 9 26 26 26 26 26 20 26 25 

M696.5D Mean 0.19 1.06 0 98.9 32 64 4 12.1 11.7 110 469 8.3 58.7 12 14.6  Median 0.2 0.95 0 100 36 100 3 10.2 11.9 105 477 8.4 59 11 12.6  Minimum 0 0.46 0 90 4 0 0 0 4.9 50 348 7.5 30 3 1.7  Maximum 0.2 1.92 0.04 100 49 100 15 30.9 25 328 600 8.9 97 33 41.8  Std. dev. 0.04 0.4 0.01 3.33 16.4 48.2 4.8 10.9 3.58 53 54.1 0.37 18.5 7.73 10.2 

N obs. 26 26 26 9 9 9 9 26 26 26 26 26 18 26 25 

M701.1B Mean 0.2 2.07 0.33 75 12 29 0 11.4 11.3 99 433 8.4 87.5 10 13.1  Median 0.2 1.91 0.23 90 14 10 0 9.6 11.6 96 452 8.4 68 12 15.1  Minimum 0.2 1.1 0.08 10 4 10 0 0 6.3 79 285 7.9 48 2 2.2  Maximum 0.2 3.2 0.74 100 21 99 1 27.2 18 157 561 9.1 199 17 23.6  Std. dev. 0 0.59 0.2 37.7 6.76 39.3 0.5 10.5 3.26 15.9 77.2 0.27 41.2 4.85 7.29 

N obs. 26 24 25 5 5 5 4 26 26 26 26 26 26 26 25 
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)

1995 Near-surface measurements: 

M702.7T Mean 0.2 — — 99.9 13 83 4 11.8 10.8 93 299 8.1 — 9 11.1  Median 0.2 — — 100 11 90 2 10.1 10.5 92 330 8.1 — 8 8  Minimum 0.2 — — 99 2 20 0 0.1 2.9 35 83 7.1 — 3 2.1  Maximum 0.2 — — 100 22 100 13 30.8 18.9 151 522 9.3 — 22 57.5  Std. dev. 0 — — 0.38 6.87 28.5 5.7 11.1 4.09 23.2 134 0.46 — 5.03 11 

N obs. 26 0 0 7 7 7 6 26 26 26 26 26 0 24 25 

R000.1M Mean 0.2 1.28 0.45 90 29 81 3 10.5 10.3 90 525 8.3 64.2 22 53.6  Median 0.2 1.22 0.45 92.5 28 97 4 9.4 10.3 94 527 8.3 68 17 43.3  Minimum 0.2 0.83 0.39 75 14 1 0 -0.1 7.7 64 462 7.9 15 4 9  Maximum 0.2 1.97 0.51 100 44 100 6 26.7 13.4 105 558 8.8 94 170 340  Std. dev. 0 0.33 0.08 10.5 10.3 39.3 2.2 9.39 1.52 9.98 20.8 0.2 24.9 31.6 66.4 

N obs. 26 17 2 6 6 6 6 26 26 26 26 26 11 26 25 

UI02.9M Mean 0.2 0.65 — 100 29 95 4 14.2 11.3 110 487 8.4 — 15 31.9  Median 0.2 0.65 — 100 29 95 4 13.5 12 105 519 8.4 — 14 27  Minimum 0.2 0.65 — 100 25 90 1 0 7.7 60 273 8.2 — 2 3  Maximum 0.2 0.65 — 100 32 100 7 30.4 15.2 177 590 8.7 — 33 90.3  Std. dev. 0 — — 0 4.95 7.07 4.2 10.7 2.06 28.2 91.3 0.15 — 10.1 26.9 

N obs. 14 1 0 2 2 2 2 14 14 14 14 14 0 12 13 

1995 Near-bottom measurements: 

M691.3B Mean 0.75 0.95 — — — — — 21.2 8.61 94 392 8.4 — — —  Median 0.75 0.93 — — — — — 21.4 8.05 94 387 8.4 — — —  Minimum 0.5 0.74 — — — — — 11.8 2.6 31 372 7.7 — — —  Maximum 1 1.2 — — — — — 29.9 13.9 139 440 8.9 — — —  Std. dev. 0.16 0.15 — — — — — 6.35 3.78 34 23.2 0.39 — — — 

N obs. 8 8 0 — — — — 8 8 8 8 8 — 0 0 

M696.5D Mean 1.09 1.29 — — — — — 11.6 10.9 97 477 8.4 — 8 —  Median 1.1 1.31 — — — — — 12.3 11.6 102 471 8.5 — 8 —  Minimum 0.6 0.82 — — — — — 1 1.8 21 405 7.5 — 8 —  Maximum 1.5 1.69 — — — — — 23.5 16.3 153 648 9 — 8 —  Std. dev. 0.27 0.26 — — — — — 8.23 4.52 40 79.2 0.47 — — — 

N obs. 8 8 0 — — — — 8 8 8 8 8 — 1 0 
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)

1996 Near-surface measurements: 

BK01.0M Mean 0.2 2.38 — 86.9 30 45 1 11.3 10.1 93 217 8.2 — 7 8.1  Median 0.2 2.35 — 100 34 45 0 11.9 9.6 94 227 8.1 — 6 8.1  Minimum 0.2 2.3 — 5 1 0 0 0 7.2 49 106 7.1 — 4 1.5  Maximum 0.2 2.5 — 100 58 100 5 27.2 18.3 183 324 9.6 — 13 20.9  Std. dev. 0 0.1 — 33.3 21.2 41.4 1.9 9.83 2.4 30.9 67.9 0.66 — 2.77 4.39 

N obs. 25 3 0 8 8 8 7 25 25 25 25 25 0 25 25 

BK14.2M Mean 0.2 — — 97.5 10 43 3 10.6 9.85 89 139 7.7 — 8 12  Median 0.2 — — 97.5 10 43 3 10.4 10.1 92 143 7.6 — 8 9.3  Minimum 0.2 — — 95 3 0 0 -0.1 7.2 49 57 6.8 — 3 2.5  Maximum 0.2 — — 100 17 85 6 24.8 12.3 139 197 8.9 — 13 31.6  Std. dev. 0 — — 3.54 9.9 60.1 4.2 9.24 1.49 21.9 43.8 0.54 — 3.1 8.59 

N obs. 24 0 0 2 2 2 2 24 24 24 24 24 0 24 24 

BX00.4M Mean 0.2 — — 100 14 35 1 9.2 10.9 94 481 8.2 — 14 31.2  Median 0.2 — — 100 14 20 0 10.1 10.9 95 476 8.2 — 11 24.2  Minimum 0.2 — — 100 1 0 0 0 8.6 77 457 7.7 — 4 4.2  Maximum 0.2 — — 100 25 100 2 19.9 14.2 132 513 8.4 — 37 92.1  Std. dev. 0 — — 0 10.6 45.1 1 7.22 1.57 10.8 14 0.18 — 8.34 23.3 

N obs. 25 0 0 4 4 4 4 25 25 25 25 25 0 25 25 

CC00.6M Mean 0.2 — — 100 20 30 2 9.36 10.8 93 494 8.2 — 17 42  Median 0.2 — — 100 18 10 0 9.4 10.8 94 494 8.2 — 13 30  Minimum 0.2 — — 100 7 0 0 -0.1 8.5 72 468 7.6 — 5 7.4  Maximum 0.2 — — 100 36 100 6 20.1 13.5 112 529 8.5 — 45 128  Std. dev. 0 — — 0 12.6 46.9 3 7.48 1.42 9.89 13 0.18 — 11.6 34 

N obs. 25 0 0 4 4 4 4 25 25 25 25 25 0 25 25 

LX00.1M Mean 0.2 — — 100 32 68 3 10.5 11.4 102 342 8.4 — 16 33.5  Median 0.2 — — 100 32 68 3 11.4 11 97 346 8.2 — 17 33.6  Minimum 0.2 — — 100 23 40 1 -0.1 7.8 66 270 7.3 — 4 7  Maximum 0.2 — — 100 41 95 4 23.8 16.3 167 401 9.2 — 35 81.6  Std. dev. 0 — — 0 12.7 38.9 2.1 9.19 2.12 25.9 31 0.54 — 9.02 21.2 

N obs. 25 0 0 2 2 2 2 25 25 25 25 25 0 25 25 

M679.5V Mean 0.2 1 0.12 95.5 30 69 6 10.4 11.3 102 404 8.4 48.2 15 22.3  Median 0.2 0.96 0.09 100 34 95 4 7.3 11.6 97 389 8.3 47 14 21.8  Minimum 0.2 0.68 0 75 1 0 0 0 8.3 62 294 7.8 22 2 1.1  Maximum 0.2 1.97 0.41 100 52 100 26 27.5 14 179 526 9.5 87 35 65.4  Std. dev. 0 0.31 0.1 9.56 16.1 40.9 8.1 10.4 1.76 30.5 62.7 0.49 15.1 9.77 19.1 

N obs. 26 26 26 10 10 10 10 26 26 26 26 26 17 25 26 
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)

1996 Near-surface measurements: 

M681.3B Mean 0.2 — — — — — — 11.1 11.6 105 399 8.4 — 18 25  Median 0.2 — — — — — — 11.7 11.3 95 379 8.2 — 19 24.9  Minimum 0.2 — — — — — — 0 7.1 57 302 7.6 — 2 1.4  Maximum 0.2 — — — — — — 26.3 19.7 190 518 9.4 — 50 80  Std. dev. 0 — — — — — — 9.9 2.59 33.3 60 0.49 — 13.6 21.6 

N obs. 25 0 0 0 0 0 0 25 25 25 25 25 0 25 25 

M691.3B Mean 0.2 1 0.01 100 32 71 6 10.5 9.37 88 435 8.2 65.6 9 10.9  Median 0.2 0.95 0 100 36 100 3 5.65 10.2 98 391 8.4 60.5 9 10  Minimum 0.2 0.67 0 100 6 0 0 0.1 0 0 317 7.1 39 3 1.8  Maximum 0.2 1.9 0.05 100 47 100 24 27.7 17.9 157 682 9.1 110 21 26  Std. dev. 0 0.24 0.01 0 13.5 42.4 7.6 10.5 4.6 47.2 101 0.6 19 5.4 7.14 

N obs. 28 28 26 11 12 11 10 28 28 28 28 28 18 28 28 

M696.5D Mean 0.2 1.13 0 97.5 38 67 7 10.7 10.4 96 430 8.3 60.8 15 18.4  Median 0.2 1.02 0 100 42 100 2 7.1 11.3 94 430 8.3 52 9 9  Minimum 0.2 0.7 0 75 4 0 0 0.2 3.5 24 280 7.5 29 3 1.6  Maximum 0.2 2.3 0.02 100 63 100 28 27.1 15.4 181 521 8.9 100 49 94.9  Std. dev. 0 0.4 0.01 7.91 21.6 46.4 9 10.7 3.45 40.9 60.6 0.44 25.3 13.5 21.8 

N obs. 26 26 25 10 10 10 9 26 26 26 26 26 19 26 26 

M701.1B Mean 0.2 2.08 0.28 99 25 81 5 10.2 10.6 93 366 8.3 86 10 12.3  Median 0.2 1.99 0.2 100 24 100 5 7.35 10.4 92 354 8.1 74 10 12.6  Minimum 0.2 0.94 0.07 95 13 0 0 0 7.5 67 226 7.7 32 3 1.5  Maximum 0.2 3.35 0.88 100 33 100 12 24.7 13.3 128 495 9.3 178 19 33.9  Std. dev. 0 0.61 0.2 2 7.09 40 4.3 10.2 1.73 17.9 64 0.42 39.8 4.79 8.45 

N obs. 26 26 26 6 6 6 6 26 26 26 26 26 25 25 26 

M702.7T Mean 0.2 — — 88.9 19 60 4 11.4 9.94 91 236 8.1 — 8 9.9  Median 0.2 — — 100 14 90 1 12.4 9.95 91 268 8.1 — 7 6.5  Minimum 0.2 — — 1 1 0 0 0 6.2 42 80 7 — 3 1.9  Maximum 0.2 — — 100 59 100 20 28.1 17.4 169 396 9.5 — 17 42.9  Std. dev. 0 — — 33 19.6 46.6 7.2 10.2 2.53 30.6 99.7 0.61 — 3.58 9.31 

N obs. 24 0 0 9 9 9 8 24 24 24 24 24 0 24 24 

R000.1M Mean 0.2 1.54 0.34 96.3 27 86 7 9.56 10.4 90 518 8.3 93.4 14 32.1  Median 0.2 1.53 0.3 100 28 100 5 7.95 10.5 92 521 8.3 106 7 15.6  Minimum 0.2 1 0.23 80 5 5 0 0 7.9 57 343 7.7 27 3 5.7  Maximum 0.2 2.27 0.52 100 46 100 18 24.4 13.1 148 580 8.6 160 67 182  Std. dev. 0 0.47 0.13 7.44 16 33 6.1 9.32 1.49 17.6 45.4 0.23 46.8 16 41.3 

N obs. 26 12 4 8 8 8 8 26 26 26 26 26 8 26 26 
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)

1996 Near-surface measurements: 

UI02.9M Mean 0.2 — — 99.8 26 89 2 10.3 10.8 95 534 8.2 — 14 31.4  Median 0.2 — — 100 24 93 2 11.8 10.6 96 534 8.2 — 8 13.8  Minimum 0.2 — — 99 18 70 0 -0.1 8.3 72 471 7.4 — 3 2.8  Maximum 0.2 — — 100 37 99 5 22.8 14.1 122 594 8.5 — 67 150  Std. dev. 0 — — 0.5 8.58 12.9 2.1 8.59 1.4 13.8 35.3 0.23 — 16.9 36.6 

N obs. 25 0 0 4 4 4 4 25 25 25 25 25 0 25 25 

1996 Near-bottom measurements: 

M691.3B Mean 0.88 1.04 — — — — — 13 7.84 80 431 8.1 — — —  Median 0.85 0.96 — — — — — 12.3 8 90 388 8.4 — — —  Minimum 0.6 0.85 — — — — — 0.6 1.8 13 329 7.1 — — —  Maximum 1.7 1.9 — — — — — 27.4 15 157 590 9 — — —  Std. dev. 0.26 0.24 — — — — — 10.4 4.17 49.7 88.7 0.61 — — — 

N obs. 18 18 0 — — — — 18 17 17 17 18 — 0 0 

M696.5D Mean 1.04 1.23 — — — — — 13.1 9.72 93 430 8.2 — — —  Median 1 1.21 — — — — — 12.9 9.4 95 439 8.2 — — —  Minimum 0.5 0.7 — — — — — 0.5 5.7 41 280 7.4 — — —  Maximum 2.1 2.3 — — — — — 26.9 13.8 136 534 8.8 — — —  Std. dev. 0.5 0.5 — — — — — 10.4 2.52 31.1 64.9 0.45 — — — 

N obs. 11 11 0 — — — — 11 11 11 11 11 — 0 0 
E-15

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)

Sodium 

1993 Near-surface measurements: 

B001.0N Mean 2.93 0.07 0.8 0.13 0.068 3.88 29 2.38 — —  Median 1.69 0.05 0.52 0.11 0.064 3.1 34.6 2.3 — —  Minimum 0.99 -0.02 0.16 0.1 0.047 2.02 8.5 2.2 — —  Maximum 5.17 0.2 2.25 0.19 0.12 7.2 44 2.7 — —  Std. dev. 1.929 0.059 0.783 0.041 0.025 2.073 18.39 0.183 — — 

N obs. 4 7 7 4 7 7 3 6 0 0 

BK01.0M Mean 2.28 0.07 0.94 0.16 0.07 5.19 31.1 2.78 — —  Median 2.29 0.05 0.81 0.15 0.047 5.39 30 2.74 — —  Minimum 1.29 -0.02 0.41 0.11 0.036 3.74 24.6 2.31 — —  Maximum 3.49 0.2 1.76 0.25 0.17 6.58 42.8 3.1 — —  Std. dev. 0.728 0.048 0.388 0.043 0.041 0.763 6.951 0.288 — — 

N obs. 13 15 15 13 15 15 5 8 0 0 

BK14.2M Mean 1.78 0.05 0.64 0.18 0.084 4.41 14.9 2.46 — —  Median 1.59 0.05 0.68 0.17 0.076 4.74 12.8 2.42 — —  Minimum 1.06 -0.02 0.15 0.096 0.046 2.25 9.6 2.09 — —  Maximum 3.56 0.09 1.2 0.32 0.14 6.88 24.5 3.2 — —  Std. dev. 0.582 0.024 0.288 0.06 0.029 1.292 5.757 0.317 — — 

N obs. 15 19 19 15 19 19 5 11 0 0 

CC00.6M Mean 1.84 0.06 0.91 0.19 0.057 5.73 62.1 1.87 — —  Median 1.7 0.06 0.9 0.13 0.054 5.72 59.6 1.4 — —  Minimum 0.83 -0.02 0.54 0.071 0.018 4.35 55.3 1.2 — —  Maximum 2.96 0.1 1.26 0.59 0.12 6.61 76.7 4 — —  Std. dev. 0.56 0.033 0.154 0.138 0.027 0.575 8.438 0.874 — — 

N obs. 16 19 19 16 19 19 5 11 0 0 

LX00.1M Mean 2.49 0.07 1.14 0.19 0.06 5.07 42.7 2.09 — —  Median 2.21 0.06 1.08 0.19 0.046 4.8 42 2 — —  Minimum 1.11 -0.02 0.46 0.072 -0.01 3.28 29.9 1.6 — —  Maximum 5.79 0.2 2.04 0.3 0.14 7.2 55.8 2.8 — —  Std. dev. 0.99 0.059 0.44 0.071 0.037 1.023 8.749 0.396 — — 

N obs. 17 22 22 17 22 22 8 14 0 0 

M679.5V Mean 3.58 0.05 2.68 0.18 0.095 6.56 64.1 2.53 — —  Median 3.69 0.04 2.67 0.18 0.086 6.46 59.6 2.4 — —  Minimum 1.03 -0.02 1.85 0.071 0.038 3.61 48 1.8 — —  Maximum 4.75 0.1 4.01 0.28 0.2 9.17 100 3.2 — —  Std. dev. 0.89 0.029 0.571 0.07 0.051 1.609 18.44 0.455 — — 

N obs. 16 20 20 16 20 20 6 12 0 0 
E-16

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 

1993 Near-surface measurements: 

M681.3B Mean 3.61 0.04 2.47 0.18 0.091 6.55 63.5 2.62 — —  Median 3.35 0.04 2.44 0.19 0.085 6.08 59.8 2.5 — —  Minimum 2.74 -0.02 1.83 0.071 0.03 3.05 55.8 2.09 — —  Maximum 5.18 0.1 3.67 0.27 0.19 9.64 77 3.3 — —  Std. dev. 0.794 0.03 0.515 0.066 0.054 1.788 8.447 0.407 — — 

N obs. 14 16 16 14 16 16 5 10 0 0 

M691.3B Mean 2.41 0.05 1.21 0.13 0.037 3.52 55.7 2.07 — —  Median 1.88 0.03 0.028 0.11 -0.01 2.7 53 2 — —  Minimum 1.19 -0.02 -0.01 0.047 -0.01 0.11 34.5 1.2 — —  Maximum 5.15 0.3 5.14 0.22 0.2 7.66 74.7 2.6 — —  Std. dev. 1.283 0.061 1.837 0.057 0.055 2.492 15.43 0.426 — — 

N obs. 16 19 19 16 19 19 5 11 0 0 

M696.5D Mean 3.13 0.06 1.6 0.15 0.074 5.94 57.1 2.48 — —  Median 2.6 0.05 1.44 0.14 0.04 5.96 58.1 2.8 — —  Minimum 1.06 -0.02 0.17 0.062 -0.01 0.54 48 1.2 — —  Maximum 9.61 0.3 3.74 0.27 0.22 8.38 64 3.4 — —  Std. dev. 2.014 0.062 1.044 0.067 0.067 2.091 6.215 0.735 — — 

N obs. 15 19 19 15 19 19 5 11 0 0 

M701.1B Mean 3.2 0.06 2.1 0.16 0.097 6.43 49.8 2.83 — —  Median 3.05 0.06 1.99 0.18 0.097 6.3 49.5 2.9 — —  Minimum 1.36 -0.02 1.39 0.065 0.044 3.19 34.2 2 — —  Maximum 4.66 0.2 3.23 0.27 0.2 9.09 63.8 3.8 — —  Std. dev. 0.745 0.037 0.551 0.058 0.049 1.738 9.272 0.508 — — 

N obs. 17 21 21 17 21 21 7 13 0 0 

M702.7T Mean 2.57 0.05 1.35 0.16 0.089 5.39 50.3 2.84 — —  Median 2.39 0.04 1.42 0.17 0.086 5.8 48.2 2.84 — —  Minimum 1.34 -0.02 0.25 0.048 0.043 2.37 41.4 2.4 — —  Maximum 4.17 0.1 2.49 0.3 0.17 8.38 67.3 3.4 — —  Std. dev. 0.769 0.039 0.601 0.057 0.036 1.76 10.28 0.316 — — 

N obs. 15 19 19 15 19 19 5 11 0 0 

R000.1M Mean 5.29 0.04 4.46 0.16 0.072 6.35 76.6 1.6 — —  Median 5.17 0.03 4.14 0.14 0.063 6.23 73.8 1.42 — —  Minimum 3.72 -0.02 3.57 0.019 0.021 4.96 71.4 1.2 — —  Maximum 6.98 0.1 5.89 0.41 0.17 8.36 90 2.2 — —  Std. dev. 0.903 0.032 0.768 0.107 0.046 0.882 6.79 0.344 — — 

N obs. 17 20 20 17 20 20 6 12 0 0 
E-17

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: 

BK01.0M Mean 1.52 0.1 0.81 0.14 0.035 4.44 30.1 2.69 12.2 6.8 Median 1.49 0.04 0.74 0.11 0.035 4.85 28.8 2.46 11.3 5.8 Minimum 0.96 -0.02 -0.01 0.062 -0.01 0.095 10.9 1.77 4.62 2.1 Maximum 2.51 0.6 1.9 0.63 0.11 7.58 53.7 4.65 21.7 25. Std. dev. 0.41 0.149 0.548 0.116 0.025 2.016 10.03 0.636 4.356 4.43

N obs. 25 26 26 25 26 26 26 26 26 2

BK14.2M Mean 1.53 0.1 0.84 0.18 0.043 4.26 16.8 2.5 6.91 4.5 Median 1.32 0.02 0.7 0.12 0.036 4.25 15.6 2.22 6.71 3.0 Minimum 0.94 -0.02 0.47 0.071 -0.01 0.97 6.62 1.5 2.42 1.8 Maximum 5.01 0.9 1.51 0.6 0.25 7.12 34.7 4.62 13.7 28. Std. dev. 0.78 0.231 0.312 0.14 0.046 1.552 6.016 0.846 2.377 5.18

N obs. 26 26 26 26 26 26 26 26 26 2

CC00.6M Mean 1.39 0.07 1.54 0.13 0.023 4.89 53.4 1.85 29.9 4.1 Median 1.37 0.03 0.96 0.1 0.01 5.19 56.1 1.44 31.7 2.9 Minimum 1.03 -0.02 0.77 0.033 -0.01 3.26 0.95 1.02 0.24 0. Maximum 2.49 0.6 15.7 0.52 0.2 5.9 76.7 5.5 43 31. Std. dev. 0.331 0.143 2.892 0.103 0.04 0.722 15.14 1.136 9.136 5.66

N obs. 25 26 26 26 25 23 26 26 26 2

LX00.1M Mean 1.88 0.1 1.15 0.22 0.047 4.4 36 2.84 17.6 5.4 Median 1.69 0.03 1.08 0.16 0.037 4.84 35.8 2.13 17.9 4.3 Minimum 1.25 -0.02 0.5 0.072 -0.01 2.13 20 1.44 9.97 3.0 Maximum 3.7 1.2 2.1 0.77 0.26 6.76 47.7 11.9 23.5 28. Std. dev. 0.653 0.247 0.429 0.184 0.058 1.393 6.532 2.306 3.613 4.97

N obs. 24 24 24 24 24 23 24 24 24 2

M679.5V Mean 2.38 0.04 1.66 0.14 0.037 5.09 52.9 2.74 21.2 9.2 Median 2.42 -0.02 1.6 0.14 0.029 5.49 53 2.73 20.2 8.9 Minimum 1.55 -0.02 0.58 0.059 -0.01 1.19 42.1 1.8 15.7 4.5 Maximum 3.41 0.3 2.76 0.29 0.1 7.3 68.8 3.96 30.3 12. Std. dev. 0.467 0.07 0.588 0.06 0.028 1.735 7.67 0.505 3.812 1.85

N obs. 21 22 22 21 22 22 22 22 22 2

M681.3B Mean 2.65 0.1 1.74 0.17 0.055 5.15 52.4 2.84 20.8 9. Median 2.58 -0.02 1.8 0.14 0.038 5.62 52.2 2.55 21.1 9.2 Minimum 1.77 -0.02 0.2 0.059 -0.01 1.94 25.3 1.77 8.03 5.2 Maximum 5.75 1.2 2.67 0.5 0.33 7.37 75.1 8.47 29.6 25. Std. dev. 0.818 0.249 0.599 0.099 0.066 1.444 10.11 1.279 4.715 3.75

N obs. 25 25 25 25 25 25 25 25 25 2
E-18

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: 

M691.3B Mean 1.18 0.08 0.39 0.09 0.018 1.75 42.6 2.82 22.6 5.2 Median 1.07 -0.02 0.11 0.088 -0.01 1.57 41 2.49 20.9 4.8 Minimum 0.56 -0.02 -0.01 0.022 -0.01 0.072 25.7 1.86 16.5 1.8 Maximum 3.09 0.7 4.37 0.19 0.12 6.42 80.6 4.08 43.7 9.8 Std. dev. 0.511 0.173 0.939 0.043 0.028 1.692 12.81 0.766 5.961 1.90

N obs. 22 23 23 22 23 23 23 23 23 2

M696.5D Mean 1.57 0.1 0.97 0.13 0.026 4.45 53.7 2.58 25.5 6. Median 1.41 0.07 0.87 0.11 0.01 4.75 52 2.49 26.8 5.9 Minimum 0.82 -0.02 0.11 0.026 -0.01 0.54 37.1 1 15.1 0. Maximum 3.05 0.6 2.73 0.33 0.16 6.75 80.5 6.09 37.8 29. Std. dev. 0.623 0.162 0.691 0.081 0.039 1.64 9.469 1.172 5.612 5.67

N obs. 23 23 23 23 23 23 23 23 23 2

M701.1B Mean 2.11 0.09 1.47 0.17 0.054 5.17 46.9 2.96 19 9.7 Median 2.13 -0.02 1.41 0.14 0.039 5.7 45.8 2.79 18 9.1 Minimum 0.96 -0.02 0.69 0.069 -0.01 1.49 30.4 1.83 12 4.4 Maximum 3.72 0.6 2.52 0.46 0.15 7.07 74.6 4.62 28.6 24. Std. dev. 0.55 0.168 0.505 0.09 0.042 1.756 10.14 0.641 4.597 3.86

N obs. 23 24 24 23 24 23 24 24 24 2

M702.7T Mean 1.79 0.1 1.07 0.16 0.046 4.51 32.8 2.86 14 7.4 Median 1.54 0.03 0.89 0.12 0.046 5.29 31.9 2.7 13.2 6. Minimum 0.68 -0.02 0.31 0.044 -0.01 0.42 13.1 1.74 4.7 2.2 Maximum 5.97 0.5 2.33 0.49 0.11 7.43 63.8 4.71 35.7 24. Std. dev. 1.022 0.158 0.532 0.1 0.029 1.908 13.78 0.699 7.191 4.75

N obs. 24 24 24 24 24 23 24 24 24 2

R000.1M Mean 3.52 0.05 3.14 0.12 0.02 5.29 69 1.75 25.6 5.3 Median 3.46 -0.02 3.46 0.085 -0.01 5.46 68.8 1.56 25.8 4.1 Minimum 2.54 -0.02 -0.01 0.031 -0.01 3.33 43.4 0.96 13.8 0. Maximum 4.95 0.4 4.8 0.61 0.17 7.23 91.1 5.58 32.6 28. Std. dev. 0.559 0.092 1.053 0.121 0.034 1.126 10.59 0.895 3.676 5.3

N obs. 23 23 23 23 23 22 23 23 23 2
E-19

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: 

BK01.0M Mean 1.52 0.07 0.66 0.11 0.037 4.81 28.7 2.69 12.3 5.9 Median 1.41 0.05 0.58 0.08 0.032 5.22 28.6 2.58 12.1 5.5 Minimum 0.65 -0.02 -0.01 0.036 -0.01 0.96 13.3 1.17 4.95 1. Maximum 2.45 0.3 1.56 0.39 0.11 7.09 55 8.1 33.3 10. Std. dev. 0.42 0.069 0.559 0.074 0.03 1.713 12.14 1.239 6.513 2.5

N obs. 26 26 26 26 26 26 26 26 26 2

BK14.2M Mean 1.7 0.06 0.68 0.12 0.049 4.78 16.9 2.81 7.53 3.2 Median 1.3 0.04 0.53 0.12 0.044 4.76 15.2 2.22 6.58 3.3 Minimum 0.78 -0.02 0.089 0.049 -0.01 2.59 7.55 0.96 2.87 1.0 Maximum 10.3 0.3 1.4 0.27 0.15 7.08 55 13.2 33.4 6.0 Std. dev. 1.795 0.077 0.396 0.058 0.032 1.407 9.459 2.289 5.83 1.0

N obs. 26 26 26 26 26 25 26 26 26 2

BX00.4M Mean 1.56 0.07 1.04 0.086 0.01 5.52 55.9 1.29 33.7 2.7 Median 1.58 0.05 0.96 0.082 -0.01 5.54 56 1.2 33.8 2.4 Minimum 1.23 0.03 0.82 0.026 -0.01 5 49.8 0.99 29.6 1.0 Maximum 1.81 0.1 1.47 0.19 0.029 6.18 61.9 1.8 38.3 4.5 Std. dev. 0.165 0.035 0.213 0.045 0.008 0.366 3.446 0.252 2.451 1.18

N obs. 14 14 14 14 14 14 14 14 14 1

CC00.6M Mean 1.4 0.06 0.92 0.13 0.014 5.74 57.2 1.74 32.8 3.1 Median 1.33 0.05 0.88 0.07 0.012 5.83 57.6 1.44 33 3.2 Minimum 0.98 0.03 0.73 0.027 -0.01 3.99 36 0.54 18.6 1. Maximum 2.31 0.2 1.16 0.71 0.04 7.16 68.3 4.56 37.5 5.6 Std. dev. 0.297 0.036 0.143 0.153 0.011 0.578 5.918 0.951 3.765 1.02

N obs. 26 26 26 26 26 26 26 26 26 2

LX00.1M Mean 1.79 0.07 1.16 0.13 0.036 5.53 39.9 2.21 19.9 4.9 Median 1.81 0.04 1.1 0.13 0.035 5.66 38.9 2.1 18.9 4.6 Minimum 1.14 -0.02 0.11 0.038 -0.01 3.22 29.5 0.84 15.3 2.5 Maximum 2.41 0.3 2.05 0.25 0.07 7.13 60.9 4.08 30.2 1 Std. dev. 0.283 0.065 0.501 0.058 0.017 1.044 6.875 0.734 3.208 1.80

N obs. 26 26 26 26 26 26 26 26 26 2

M679.5V Mean 2.75 0.05 1.97 0.11 0.044 5.42 58.2 2.97 23.8 11. Median 2.77 0.04 2.08 0.093 0.039 5.41 61.5 2.88 25 1 Minimum 1.48 -0.02 0.34 0.047 -0.01 -0.05 40.5 1.92 16.3 6.2 Maximum 4.02 0.1 3.44 0.29 0.085 8.43 85 4.9 37.9 17. Std. dev. 0.628 0.03 0.766 0.055 0.025 2.034 11.08 0.679 5.233 3.52

N obs. 26 26 26 26 26 25 26 26 26 2
E-20

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: 

M681.3B Mean 2.77 0.05 1.96 0.11 0.045 5.77 56.4 2.56 23.6 10. Median 2.7 0.04 2.08 0.084 0.041 5.95 55.8 2.49 23.3 10. Minimum 1.49 -0.02 0.49 0.037 -0.01 1.65 40.5 1.38 15.3 4.2 Maximum 3.86 0.3 3.25 0.22 0.11 8.54 70 4.68 33.7 1 Std. dev. 0.624 0.054 0.728 0.058 0.029 1.589 8.708 0.691 4.701 2.6

N obs. 26 26 26 26 26 26 26 26 26 2

M691.3B Mean 1.67 0.05 0.3 0.097 0.008 2.03 51.8 2.57 27.7 7.2 Median 1.53 0.03 -0.01 0.088 -0.01 1.57 43.9 2.37 25.9 6.8 Minimum 0.77 -0.02 -0.01 0.027 -0.01 -0.05 35.5 1.59 17.4 4.4 Maximum 4.23 0.5 2.16 0.26 0.028 7.49 92.2 4.05 49.6 13. Std. dev. 0.77 0.093 0.551 0.065 0.005 1.918 16.22 0.739 8.072 2.10

N obs. 26 26 26 26 26 26 26 26 26 2

M696.5D Mean 1.88 0.07 1.01 0.092 0.025 4.95 57.5 2.91 27.9 9.6 Median 1.54 0.06 0.9 0.08 0.02 4.68 56.6 2.61 28.1 8.7 Minimum -0.1 -0.02 0.035 0.028 -0.01 0.72 41.8 1.26 16.1 2.3 Maximum 6.68 0.2 2.27 0.2 0.096 8.37 79 4.6 40.5 28. Std. dev. 1.215 0.049 0.612 0.048 0.024 1.872 9.757 0.951 6.8 5.68

N obs. 26 26 26 26 26 26 26 26 26 2

M701.1B Mean 2.51 0.06 1.68 0.13 0.06 5.97 51.9 3.22 21.4 11. Median 2.47 0.06 1.8 0.094 0.059 6.66 53.5 2.91 22.4 10. Minimum 1.53 -0.02 0.3 0.044 -0.01 2.2 35.3 2.1 13.6 5.6 Maximum 3.61 0.3 3.02 0.75 0.12 8.86 84.1 5.8 37.7 21. Std. dev. 0.536 0.051 0.643 0.133 0.036 1.918 11.9 0.938 5.671 4.15

N obs. 26 26 26 26 26 25 25 25 25 2

M702.7T Mean 1.85 0.06 1.06 0.11 0.059 5.36 33.1 3.03 13.6 7.2 Median 1.82 0.05 1.02 0.093 0.045 6.03 34.7 2.76 13.1 6.2 Minimum 0.77 -0.02 0.091 0.042 -0.01 1.96 8.26 1.26 3.17 2.1 Maximum 2.91 0.3 2.11 0.29 0.2 8.51 57.8 9.78 25.8 14. Std. dev. 0.565 0.065 0.621 0.06 0.047 1.953 16.82 1.502 7.331 3.76

N obs. 26 26 26 26 25 25 25 26 26 2

R000.1M Mean 3.93 0.04 3.77 0.091 0.014 5.49 73.7 1.96 27.4 4. Median 3.69 0.03 3.72 0.069 0.012 5.66 72 1.65 27.3 4. Minimum 2.8 -0.02 2.35 0.024 -0.01 1.73 61.8 1.17 18.9 2.0 Maximum 6.88 0.1 5.72 0.32 0.033 7.97 97 4.47 36.8 8.1 Std. dev. 0.869 0.026 0.859 0.073 0.009 1.455 8.114 0.937 3.689 1.34

N obs. 25 26 26 25 26 26 26 26 26 2
E-21

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: 

UI02.9M Mean 3.2 0.04 2.85 0.074 0.012 4.79 68.3 1.92 27 5.0 Median 2.92 0.03 2.66 0.066 -0.01 4.58 72 1.8 27.3 4.8 Minimum 2.59 -0.02 1.7 0.032 -0.01 2.9 11.1 1.2 5.02 3.0 Maximum 4.51 0.1 4 0.13 0.048 6.26 89 3.3 37.6 7.9 Std. dev. 0.565 0.029 0.869 0.034 0.013 1.046 17.96 0.56 7.027 1.26

N obs. 14 14 14 14 14 14 14 14 14 1

1996 Near-surface measurements: 

BK01.0M Mean 1.25 0.2 0.55 0.096 0.04 3.8 21 3.35 8.46 4.3 Median 1.12 0.09 0.46 0.091 0.042 3.79 20.2 2.94 8.24 4.6 Minimum 0.35 -0.02 -0.01 0.033 -0.01 0.69 10.7 2.01 4.11 -0.0 Maximum 2.13 0.6 1.38 0.18 0.1 7.29 35 5.61 14.9 8.0 Std. dev. 0.546 0.174 0.495 0.037 0.024 2.09 6.872 1.046 2.978 1.71

N obs. 25 20 25 15 25 24 25 25 25 2

BK14.2M Mean 1.26 0.1 0.67 0.11 0.041 4.16 13 3.23 5.45 2.0 Median 1.11 0.04 0.65 0.1 0.033 4.36 12.8 2.82 5.45 1.9 Minimum 0.79 -0.02 0.21 0.054 0.012 1.65 5.91 2.07 2.36 -0.0 Maximum 2.28 0.7 1.31 0.16 0.12 7.28 22.2 6.51 8.76 3.8 Std. dev. 0.39 0.175 0.275 0.029 0.024 1.586 4.645 1.078 1.929 1.24

N obs. 24 19 24 14 24 23 24 24 24 2

BX00.4M Mean 1.32 0.06 1.03 0.18 0.008 4.89 55.6 1.72 31.8 1.9 Median 1.25 0.04 0.96 0.056 -0.01 4.91 59.4 1.68 32.4 1.7 Minimum -0.1 -0.02 0.25 0.031 -0.01 3.02 27 1.2 17.1 -0.0 Maximum 2.82 0.2 1.86 2.05 0.026 6.07 68.8 2.55 39.7 11. Std. dev. 0.542 0.042 0.329 0.498 0.006 0.82 10.14 0.384 5.127 2.22

N obs. 25 20 25 16 25 24 25 25 25 2

CC00.6M Mean 1.48 0.06 0.91 0.081 0.009 5.23 57.1 1.71 32.1 2.5 Median 1.36 0.05 0.9 0.059 -0.01 5.29 59.7 1.77 31.8 2.3 Minimum 0.92 -0.02 0.67 0.024 -0.01 3.56 28.2 1.02 16.9 -0.0 Maximum 4.31 0.2 1.39 0.24 0.028 6.53 69.8 2.1 39.9 7.0 Std. dev. 0.683 0.049 0.173 0.053 0.007 0.753 10.1 0.291 5.191 1.8

N obs. 25 21 25 15 25 24 25 25 25 2
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)

Sodium 

1996 Near-surface measurements: 

LX00.1M Mean 1.61 0.1 1.05 0.15 0.026 5.02 38 2.58 18.7 4.0 Median 1.52 0.05 1.05 0.14 0.024 5.38 40.4 2.43 19.1 3.8 Minimum 0.52 -0.02 0.19 0.046 -0.01 1.97 15.9 1.71 9.61 -0.0 Maximum 2.88 0.4 1.93 0.54 0.084 7.32 47.4 3.96 23.7 12. Std. dev. 0.449 0.112 0.509 0.115 0.019 1.461 7.829 0.544 3.55 2.2

N obs. 25 20 25 15 25 24 25 25 25 2

M679.5V Mean 2.07 0.1 1.33 0.1 0.047 4.87 46.4 3.09 18.2 7.7 Median 1.97 0.1 1.22 0.092 0.036 5.15 43.6 2.97 16.6 7.9 Minimum 0.9 -0.02 -0.01 0.046 -0.01 2.01 18.8 1.8 7.44 4.7 Maximum 3.3 0.4 2.81 0.16 0.18 7.83 77.4 4.83 30.9 11. Std. dev. 0.721 0.124 0.871 0.037 0.039 1.814 12.67 0.761 5.296 2.04

N obs. 26 21 25 19 25 23 26 26 26 2

M681.3B Mean 1.92 0.1 1.32 0.11 0.039 4.97 45.6 3.08 17.7 7.4 Median 1.63 0.05 1.4 0.095 0.039 5.2 42.8 3.06 16.1 7.5 Minimum -0.1 -0.02 -0.01 0.054 -0.01 2.2 19.1 1.68 7.75 4. Maximum 3.79 0.3 2.85 0.18 0.094 7.9 67 4.47 27.3 11. Std. dev. 0.887 0.104 0.875 0.038 0.024 1.772 11.91 0.645 4.866 1.93

N obs. 25 20 25 16 25 24 25 25 25 2

M691.3B Mean 1.43 0.2 0.41 0.071 0.011 3 48.4 2.99 23.6 4.8 Median 1.26 0.06 0.099 0.069 -0.01 2.98 45.2 2.88 21.8 4.6 Minimum 0.69 -0.02 -0.01 0.022 -0.01 -0.05 17.7 1.5 10.7 -0.0 Maximum 2.36 0.6 2.36 0.16 0.036 6.6 97.4 5.31 43.8 10. Std. dev. 0.496 0.19 0.643 0.037 0.011 1.997 19.12 0.832 8.88 2.76

N obs. 26 21 25 18 25 22 26 26 26 2

M696.5D Mean 1.7 0.2 0.81 0.1 0.028 4.96 47.3 2.87 22.3 5.3 Median 1.38 0.1 0.58 0.082 0.017 5.55 45.7 2.91 21.2 5.3 Minimum 0.55 -0.02 -0.01 0.014 -0.01 1.93 23.9 1.02 12.1 -0.0 Maximum 4.22 0.9 2.84 0.38 0.11 8.89 70.2 5.34 35.2 13. Std. dev. 0.949 0.219 0.771 0.087 0.028 1.632 12.17 0.978 6.735 3.90

N obs. 26 21 25 19 25 23 26 26 26 2

M701.1B Mean 1.75 0.1 1.13 0.1 0.054 4.86 39.9 3.17 15.9 7.5 Median 1.75 0.09 1.12 0.092 0.058 5.35 36.8 3.09 14.9 7.1 Minimum -0.1 -0.02 -0.01 0.047 -0.01 1.76 18 2.1 7.09 4.0 Maximum 2.96 0.5 2.43 0.18 0.1 7.64 82.3 5.67 35.6 12. Std. dev. 0.719 0.133 0.714 0.034 0.028 1.66 13.87 0.812 6.24 2.2

N obs. 26 21 25 19 25 23 26 26 26 2
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)

Sodium 

1996 Near-surface measurements: 

M702.7T Mean 1.38 0.1 0.76 0.1 0.057 4.23 23.2 3.3 9.26 5.0 Median 1.23 0.06 0.62 0.088 0.05 3.98 24.4 2.91 9.71 5.1 Minimum 0.73 -0.02 -0.01 0.046 -0.01 1.69 5.37 2.1 2.11 1.5 Maximum 2.39 0.7 2.9 0.16 0.13 7.4 46 6.45 19.8 9.1 Std. dev. 0.507 0.163 0.649 0.033 0.031 1.815 10.72 1.053 4.554 2.29

N obs. 24 19 24 14 24 23 24 24 24 2

R000.1M Mean 3.35 0.07 3.13 0.074 0.017 5.3 70.9 2.18 25.6 3.0 Median 3.03 0.03 3.13 0.061 -0.01 5.38 74.2 2.07 26.1 2.9 Minimum 1.98 -0.02 1.59 0.026 -0.01 1.65 28.5 1.08 13.3 -0.0 Maximum 6.69 0.6 4.54 0.26 0.059 7.39 95.7 4.05 31.9 7.2 Std. dev. 1.112 0.118 0.814 0.051 0.017 1.419 14.58 0.668 4.535 1.74

N obs. 26 21 25 18 25 23 26 26 26 2

UI02.9M Mean 3.3 0.05 3.23 0.1 0.021 4.34 72.3 2.8 24.9 3.3 Median 2.82 0.02 2.92 0.083 0.013 4.21 72.1 2.58 25.8 3.4 Minimum 0.38 -0.02 1.5 0.012 -0.01 0.96 30.4 1.53 14.2 -0.0 Maximum 8.65 0.2 6.82 0.24 0.067 6.61 90.5 7.35 32.6 6.5 Std. dev. 1.621 0.046 1.301 0.069 0.021 1.782 13.34 1.163 4.085 1.66

N obs. 24 20 25 15 25 24 25 25 25 2
E-24

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 8 from 1993 through

1996.
E-25

Figure E-1b. Monthly means of temperature (° C), dissolved oxygen (mg/L), oxygen saturation (%), pH, specific

conductivity (:S), and turbidity (NTU) in the Black River (sites B001.0N and BK01.0M) from 1993 through 1996.
E-26

Figure E-1c. Monthly means of temperature (°C), dissolved oxygen (mg/L), oxygen saturation (%), pH, specific

conductivity (:S), and turbidity (NTU) in the La Crosse River from 1993 through 1996.
E-27

Figure E-1d. Monthly means of temperature (°C), dissolved oxygen (mg/L), oxygen saturation (%), pH, specific

conductivity (:S), and turbidity (NTU) in the Root River from 1993 through 1996.
E-28

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 8 from 1993 through 1996.
E-29

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 Black River (sites B001.0N and BK01.0M) from 1993 through 1996.
E-30

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 Root River from 1993 through 1996.
E-31

Figure E-2d. 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 La Crosse 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. D

sampling-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)

Total

suspend

solids

(mg/L

1993 Near-surface measurements: summer

1. Main channel Mean 0.2 4.63 0.77 — — — — 23.3 6.46 76 455 7.5 47 22 32.9  Median 0.2 4.3 0.82 — — — — 23.2 6.5 77 461 7.5 47 22 29.7  Minimum 0.2 2.4 0.03 — — — — 22.8 5.7 67 412 7.1 35 15 24.9  Maximum 0.2 10.3 1.22 — — — — 24 7.2 85 497 7.8 55 33 50.6  Std. dev. 0 1.92 0.3 — — — — 0.36 0.43 4.99 25 0.16 5.67 3.87 7.41 

N obs. 25 25 25 0 0 0 0 25 25 25 25 25 25 25 13 

2. Side channel Mean 0.2 2.49 0.52 — — — — 23.3 6.56 77 456 7.6 46.4 21 31.1  Median 0.2 2.35 0.5 — — — — 23.2 6.5 78 455 7.6 49 20 26.6  Minimum 0.2 0.5 0.02 — — — — 22.7 5.4 63 407 7 21 10 11.6  Maximum 0.2 5.2 1.2 — — — — 24 7.5 88 505 7.8 60 53 86.6  Std. dev. 0 1.13 0.29 — — — — 0.36 0.42 5.16 29.6 0.16 9.09 8.26 17.4 

N obs. 30 30 30 0 0 0 0 30 29 29 30 30 30 30 16 

3. Backwater Mean 0.2 1.6 0.17 — — — — 23.2 6.39 75 454 7.5 56.7 15 18.8  Median 0.2 1.4 0.07 — — — — 23.2 6.5 76 452 7.5 50 16 20  Minimum 0.2 0.4 0 — — — — 21.2 4 46 395 6.7 33 1 4.5  Maximum 0.2 4.6 0.95 — — — — 25.1 8.4 99 531 8 168 28 40.9  Std. dev. 0 0.82 0.23 — — — — 0.79 0.75 9.27 35.5 0.28 23.8 5.44 8.65 

N obs. 59 59 58 0 0 0 0 59 57 57 59 59 59 59 31 

5. Impounded Mean 0.2 1.66 0.32 — — — — 23.6 6.73 80 458 7.6 45.4 22 30.9  Median 0.2 1.4 0.31 — — — — 23.7 6.7 79 464 7.6 47 17 24.6  Minimum 0.2 1.1 0.03 — — — — 22.9 6.3 74 297 7.1 26 13 16.2  Maximum 0.2 3 0.52 — — — — 25 7.2 86 494 7.8 57 52 84.5  Std. dev. 0 0.53 0.12 — — — — 0.47 0.25 3.21 38 0.18 9.14 10.5 18 

N obs. 25 25 25 0 0 0 0 25 23 23 25 25 25 25 13 

6. Isolated Mean 0.2 0.91 0 — — — — 23.2 3.51 42 483 7.1 57.6 9 11.3  Median 0.2 0.9 0 — — — — 22.7 1.4 17 485 7.1 47 8 8.7  Minimum 0.2 0.5 0 — — — — 22 0.2 2 398 6.6 43 3 3.7  Maximum 0.2 1.4 0 — — — — 24.9 11.6 141 531 7.7 85 18 24.2  Std. dev. 0 0.34 0 — — — — 1.34 4.28 52.1 42.2 0.42 19 5.85 8.9 

N obs. 8 8 8 0 0 0 0 8 8 8 8 8 5 8 4 
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 Middepth measurements: summer

3. Backwater Mean 1.2 2.35 — — — — — 23.6 3 36 475 7.5 — 2 —  Median 1.2 2.35 — — — — — 23.6 3 36 475 7.5 — 2 —  Minimum 1.1 2.2 — — — — — 23.1 3 35 473 7.4 — 2 —  Maximum 1.3 2.5 — — — — — 24 3 36 477 7.5 — 2 —  Std. dev. 0.14 0.21 — — — — — 0.64 0 0.45 2.83 0.07 — 0 — 

N obs. 2 2 0 — — — — 2 2 2 2 2 — 2 0 

1993 Near-bottom measurements: summer

1. Main channel Mean 2.2 2.4 — — — — — 23.8 5.8 69 — — — — —  Median 2.2 2.4 — — — — — 23.8 5.8 69 — — — — —  Minimum 2.2 2.4 — — — — — 23.8 5.8 69 — — — — —  Maximum 2.2 2.4 — — — — — 23.8 5.8 69 — — — — —  Std. dev. — — — — — — — — — — — — — — — 

N obs. 1 1 0 — — — — 1 1 1 0 0 — 0 0 

2. Side channel Mean 2 2.2 — — — — — 23.1 5.85 69 — — — — —  Median 2 2.2 — — — — — 23.1 5.85 69 — — — — —  Minimum 1.3 1.5 — — — — — 23 5.5 64 — — — — —  Maximum 2.7 2.9 — — — — — 23.2 6.2 73 — — — — —  Std. dev. 0.99 0.99 — — — — — 0.14 0.49 6.01 — — — — — 

N obs. 2 2 0 — — — — 2 2 2 0 0 — 0 0 

3. Backwater Mean 1.69 1.89 0.02 — — — — 22.7 5.46 64 480 7.2 — 5 —  Median 1.6 1.8 0.02 — — — — 22.9 5.8 68 481 7.3 — 6 —  Minimum 0.5 0.7 0.01 — — — — 21.1 0.4 5 462 7 — 2 —  Maximum 4.4 4.6 0.03 — — — — 23.9 7.3 84 497 7.4 — 6 —  Std. dev. 0.81 0.81 0.01 — — — — 0.69 1.58 18.5 14.9 0.17 — 1.89 — 

N obs. 31 31 4 — — — — 31 30 30 4 4 — 4 0 

5. Impounded Mean 1.9 2.1 — — — — — 24 6.75 81 — — — — —  Median 1.85 2.05 — — — — — 24.1 6.75 81 — — — — —  Minimum 1.1 1.3 — — — — — 23.8 6.6 79 — — — — —  Maximum 2.8 3 — — — — — 24.1 6.9 82 — — — — —  Std. dev. 0.79 0.79 — — — — — 0.14 0.21 2.3 — — — — — 

N obs. 4 4 0 — — — — 4 2 2 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/

1993 Near-bottom measurements: summer

6. Isolated Mean 0.92 1.12 — — — — — 22.5 3.76 45 545 — — — —  Median 0.9 1.1 — — — — — 21.9 0.6 7 545 — — — —  Minimum 0.6 0.8 — — — — — 21.5 0.3 3 545 — — — —  Maximum 1.2 1.4 — — — — — 24 9.5 112 545 — — — —  Std. dev. 0.24 0.24 — — — — — 1.13 4.55 54.1 — — — — — 

N obs. 5 5 0 — — — — 5 5 5 1 0 — 0 0 

1993 Near-surface measurements: fall

1. Main channel Mean 0.2 4.05 0.57 — — — — 15.6 8.85 89 463 7.8 53.2 15 18.4  Median 0.2 4.2 0.62 — — — — 15.6 8.9 90 480 7.9 53 16 19.9  Minimum 0.2 1.2 0 — — — — 15 7.8 77 289 7 43 9 8.6  Maximum 0.2 7.7 0.93 — — — — 16 9.3 93 528 8.2 65 20 21.7  Std. dev. 0 1.83 0.21 — — — — 0.32 0.34 3.69 56 0.26 5.44 2.45 3.66 

N obs. 25 25 20 0 0 0 0 25 25 25 25 22 25 24 13 

2. Side channel Mean 0.2 2.12 0.25 — — — — 15 9.16 91 441 7.5 56.4 14 17.1  Median 0.2 1.5 0.23 — — — — 15.2 9.1 90 460 7.6 55 14 16.6  Minimum 0.2 0.3 0 — — — — 13.1 7.8 77 108 6.9 45 6 8.2  Maximum 0.2 6.4 0.69 — — — — 16.3 10.8 105 531 8 75 23 31  Std. dev. 0 1.57 0.17 — — — — 0.73 0.7 6.45 83.1 0.29 8.26 3.68 5.43 

N obs. 30 30 30 0 0 0 0 30 29 29 30 29 27 30 16 

3. Backwater Mean 0.2 0.99 0.09 — — — — 15.2 8.56 85 434 7.5 46.5 17 22.5  Median 0.2 0.7 0.02 — — — — 15.3 9.15 91 442 7.6 49 15 18.3  Minimum 0.2 0.1 0 — — — — 12.9 1.3 13 161 6.6 21 3 7.2  Maximum 0.2 5.8 0.58 — — — — 16.8 12.4 124 565 8.3 65 36 75.2  Std. dev. 0 0.85 0.13 — — — — 0.92 2.41 24.1 75.8 0.43 11.3 6.79 15.8 

N obs. 60 60 60 0 0 0 0 60 60 60 60 58 42 60 32 

5. Impounded Mean 0.2 1.21 0.16 — — — — 15.4 9.16 92 453 7.6 53.8 15 18.6  Median 0.2 1.1 0.15 — — — — 15.3 8.8 88 460 7.6 53 15 18.8  Minimum 0.2 0.5 0 — — — — 14.2 8.5 85 385 7.1 43 12 7.3  Maximum 0.2 2.5 0.48 — — — — 16.2 10.8 110 504 8 62 24 28  Std. dev. 0 0.46 0.1 — — — — 0.43 0.7 7.56 31.3 0.29 5.25 2.52 6.2 

N obs. 23 23 18 0 0 0 0 23 23 23 23 23 23 23 12 
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/

1993 Near-surface measurements: fall

6. Isolated Mean 0.2 1.06 0.01 — — — — 11.2 2.89 27 649 7 76.2 12 13.8  Median 0.2 0.65 0 — — — — 11.3 2.1 19 582 7 51 10 12.4  Minimum 0.2 0.2 0 — — — — 8.8 0.3 3 493 6.5 30 4 3.9  Maximum 0.2 4.5 0.03 — — — — 13 9.4 89 1128 7.8 150 25 25  Std. dev. 0 1.25 0.01 — — — — 1.62 3.22 30.6 199 0.42 50.4 6.44 10.6 

N obs. 10 10 10 0 0 0 0 10 10 10 10 10 6 10 3 

1993 Near-bottom measurements: fall

3. Backwater Mean 1.18 1.38 0.01 — — — — 14.2 7.57 74 511 7.8 — 27 —  Median 1.05 1.25 0.01 — — — — 14.2 7.7 74 511 7.8 — 27 —  Minimum 0.4 0.6 0.01 — — — — 11.2 4.3 41 511 7.8 — 27 —  Maximum 2.6 2.8 0.01 — — — — 16.2 11.6 115 511 7.8 — 27 —  Std. dev. 0.74 0.74 — — — — — 1.93 2.59 25.3 — — — — — 

N obs. 6 6 1 — — — — 6 6 6 1 1 — 1 0 

6. Isolated Mean 2.03 2.23 — — — — — 12.7 5.15 48 — — — — —  Median 1.2 1.4 — — — — — 12.7 5.15 48 — — — — —  Minimum 0.6 0.8 — — — — — 12.5 2.7 25 — — — — —  Maximum 4.3 4.5 — — — — — 12.9 7.6 71 — — — — —  Std. dev. 1.99 1.99 — — — — — 0.2 3.46 32.4 — — — — — 

N obs. 3 3 0 — — — — 3 2 2 0 0 — 0 0 

1994 Near-surface measurements: winter

1. Main channel Mean 0.2 4.77 0.23 99.2 31 83 5 -.03 12.3 84 554 7.2 163 3 1.6  Median 0.2 3.9 0.23 100 34 100 4 0 12.2 83 570 7.1 151 2 1.6  Minimum 0.2 1.5 0.08 95 6 10 0 -0.2 12 82 482 7 120 2 -0.1  Maximum 0.2 9.1 0.37 100 40 100 14 0 12.8 87 591 7.8 214 4 4.2  Std. dev. 0 2.69 0.1 1.95 9.31 31.7 4.3 0.06 0.31 2.1 36.4 0.27 32.4 0.79 0.97 

N obs. 12 10 12 12 12 12 12 12 9 9 12 12 10 12 12 

2. Side channel Mean 0.2 2.12 0.15 99.4 35 96 10 -.01 12.4 85 579 7.2 138 3 2.7  Median 0.2 2 0.12 100 35 100 8 0 12.1 83 574 7.1 131 3 2.5  Minimum 0.2 0.42 0 90 12 5 0 -0.1 11 75 492 6.4 119 2 1.2  Maximum 0.2 6.7 0.36 100 55 100 25 0 17.4 119 679 7.8 190 5 6.4  Std. dev. 0 1.33 0.08 2.12 10.8 18.5 7 0.03 1.21 8.22 35.7 0.29 20 0.62 1.32 

N obs. 27 27 27 27 27 27 26 27 26 26 27 27 21 27 27 
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: winter

3. Backwater Mean 0.18 1.24 0.06 100 35 99 11 0.07 11.2 76 592 7.3 112 3 3.2  Median 0.2 0.8 0.02 100 36 100 8 0 11.8 80 578 7.3 112 3 2.1  Minimum 0 0.25 0 100 18 60 2 -0.1 1.6 11 517 6.3 70 2 1.2  Maximum 0.2 6.7 0.3 100 50 100 27 1 15.1 103 810 7.9 171 6 11.1  Std. dev. 0.06 1.3 0.08 0 8.58 7.21 7.1 0.27 2.56 17.4 65.3 0.33 35.7 1.22 2.74 

N obs. 31 31 31 31 31 31 30 31 31 31 31 31 7 31 30 

5. Impounded Mean 0.2 1.29 0.08 100 35 100 16 0 12.6 86 565 7.1 145 3 2.1  Median 0.2 1.19 0.08 100 36 100 17 0 12.4 85 581 7.1 143 3 1.6  Minimum 0.2 0.62 0.02 100 26 100 2 -0.1 11.4 78 494 6.7 115 2 1  Maximum 0.2 2.4 0.17 100 44 100 27 0 16.1 110 655 7.6 186 5 5.4  Std. dev. 0 0.55 0.03 0 4.77 0 8 0.02 0.86 5.84 47.3 0.2 24.1 0.93 1.18 

N obs. 24 24 24 24 24 24 23 24 24 24 24 24 7 24 24 

6. Isolated Mean 0.2 2.25 0 100 45 100 7 0.9 0.65 5 1532 7.2 51 7 19.6  Median 0.2 2.25 0 100 45 100 7 0.9 0.65 5 1532 7.2 51 7 19.6  Minimum 0.2 1.4 0 100 44 100 6 0 0.5 3 963 7.1 18 5 4.2  Maximum 0.2 3.1 0 100 46 100 7 1.8 0.8 6 2100 7.2 84 9 34.9  Std. dev. 0 1.2 0 0 1.41 0 .71 1.27 0.21 1.65 804 0.07 46.7 2.83 21.7 

N obs. 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 

1994 Near-bottom measurements: winter

3. Backwater Mean 2.3 2.5 — — — — — 0.65 7.95 55 675 — — — —  Median 2.3 2.5 — — — — — 0.65 7.95 55 675 — — — —  Minimum 2.2 2.4 — — — — — 0 4.1 29 675 — — — —  Maximum 2.4 2.6 — — — — — 1.3 11.8 81 675 — — — —  Std. dev. 0.14 0.14 — — — — — 0.92 5.44 36.5 — — — — — 

N obs. 2 2 0 — — — — 2 2 2 1 0 — 0 0 

1994 Near-surface measurements: spring

1. Main channel Mean 0.2 4.88 0.84 — — — — 12.2 10.5 98 387 7.8 53.6 20 32.9  Median 0.2 4.7 0.84 — — — — 11.7 10.4 94 389 7.9 55 17 26.9  Minimum 0.2 0.72 0.28 — — — — 11 9.3 86 276 7.3 37 14 10.9  Maximum 0.2 11 1.28 — — — — 14.8 11.8 116 542 8.3 65 40 88.3  Std. dev. 0 2.5 0.3 — — — — 1.3 0.77 9.82 56.1 0.28 7.37 6.67 16.2 

N obs. 25 25 19 0 0 0 0 25 25 25 25 25 25 25 25 
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-surface measurements: spring

2. Side channel Mean 0.2 2.67 0.56 — — — — 11.9 10 93 342 7.6 57.4 15 24.6  Median 0.2 2.3 0.6 — — — — 12 9.8 90 320 7.5 58 16 24.9  Minimum 0.2 0.7 0.02 — — — — 10.4 9.3 86 154 7.1 44 8 10.2  Maximum 0.2 6.4 1 — — — — 15.2 12.7 127 453 8.4 70 25 44.5  Std. dev. 0 1.55 0.28 — — — — 0.98 0.67 8.16 66.5 0.35 6.73 3.7 6.9 

N obs. 29 29 13 0 0 0 0 29 29 29 29 29 29 29 29 

3. Backwater Mean 0.2 1.4 0.17 — — — — 13 11.5 110 340 7.7 64.5 11 17.8  Median 0.2 1.26 0.08 — — — — 12.8 10.4 98 335 7.8 62.5 11 15.4  Minimum 0.2 0.45 0 — — — — 10.8 9.2 83 105 6.7 39 4 5.2  Maximum 0.2 2.8 0.6 — — — — 16.7 17.5 170 456 8.9 98 21 45.7  Std. dev. 0 0.63 0.19 — — — — 1.33 2.25 23.4 69.8 0.52 12.6 3.93 8.63 

N obs. 60 60 19 0 0 0 0 60 60 60 60 60 56 60 60 

5. Impounded Mean 0.2 1.81 0.43 — — — — 11.7 10.1 93 361 7.7 52.1 18 28.9  Median 0.2 1.4 0.43 — — — — 11.8 10 92 371 7.8 50.5 17 27.5  Minimum 0.2 0.8 0.16 — — — — 10.4 9.3 86 276 7 46 13 12.9  Maximum 0.2 6.5 0.6 — — — — 13.8 11.8 114 430 8.3 60 29 44.3  Std. dev. 0 1.24 0.15 — — — — 0.64 0.49 5.24 48.7 0.29 4.55 3.86 7.49 

N obs. 26 26 17 0 0 0 0 26 26 26 26 26 26 26 25 

6. Isolated Mean 0.2 1.03 0 — — — — 15.4 13.8 138 405 8.4 75.5 6 10.4  Median 0.2 1.06 0 — — — — 15.1 14.1 140 401 8.5 77.5 6 10.5  Minimum 0.2 0.73 0 — — — — 15 11.6 118 388 7.9 60 4 2.8  Maximum 0.2 1.3 0 — — — — 17 15.2 157 454 8.7 98 8 15.3  Std. dev. 0 0.18 0 — — — — 0.63 1.27 13 18.9 0.27 12.9 1.32 3.65 

N obs. 10 10 8 0 0 0 0 10 10 10 10 10 8 10 10 

1994 Middepth measurements: spring

3. Backwater Mean 0.97 1.92 — — — — — 13.2 16.1 153 — — — — —  Median 0.9 1.76 — — — — — 13.2 15.7 150 — — — — —  Minimum 0.6 1.2 — — — — — 13 15.4 147 — — — — —  Maximum 1.4 2.8 — — — — — 13.3 17.2 163 — — — — —  Std. dev. 0.4 0.81 — — — — — 0.15 0.96 8.71 — — — — — 

N obs. 3 3 0 — — — — 3 3 3 0 0 — 0 0 
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-bottom measurements: spring

3. Backwater Mean 1.42 1.63 — — — — — 11.8 12.3 113 271 8.1 — 12 17  Median 1.3 1.53 — — — — — 11.9 11.7 108 269 8.1 — 12 17  Minimum 0.7 0.88 — — — — — 10.7 9 84 125 8.1 — 12 17  Maximum 2.6 2.8 — — — — — 13.3 16.4 150 413 8.1 — 12 17  Std. dev. 0.65 0.64 — — — — — 0.76 2.4 21.7 128 — — — — 

N obs. 13 13 0 — — — — 13 13 13 5 1 — 1 1 

6. Isolated Mean 0.91 1.12 — — — — — 15 13.7 136 — — — — —  Median 0.9 1.1 — — — — — 15.1 13.8 137 — — — — —  Minimum 0.8 1 — — — — — 13.8 12.4 123 — — — — —  Maximum 1.1 1.3 — — — — — 15.4 14.6 145 — — — — —  Std. dev. 0.11 0.11 — — — — — 0.53 0.83 8.22 — — — — — 

N obs. 7 7 0 — — — — 7 7 7 0 0 — 0 0 

1994 Near-surface measurements: summer

1. Main channel Mean 0.2 4.37 0.49 — — — — 24 9.48 113 420 8.2 54.3 18 25.6  Median 0.2 4.01 0.5 — — — — 23.8 9.45 112 422 8.2 55 18 26  Minimum 0.2 1.1 0.08 — — — — 22.8 8.4 98 372 7.5 41 12 19.6  Maximum 0.2 9.5 0.88 — — — — 26.1 11.8 147 464 9.1 68 23 32  Std. dev. 0 2.07 0.21 — — — — 0.78 0.66 9.09 20.2 0.29 6.61 2.68 3.36 

N obs. 26 26 24 0 0 0 0 26 26 26 26 26 26 26 26 

2. Side channel Mean 0.2 2.89 0.27 — — — — 24.4 9.6 116 406 8.3 50.6 18 25.8  Median 0.2 2.5 0.27 — — — — 24.2 9.6 115 408 8.3 52 17 24.1  Minimum 0.2 0.4 0 — — — — 22.7 8.1 96 373 7.8 27 12 12.6  Maximum 0.2 7.55 0.65 — — — — 25.9 11.8 145 426 8.7 64 29 55.5  Std. dev. 0 1.8 0.19 — — — — 0.72 0.93 12.4 13.2 0.19 9.77 4.29 9.02 

N obs. 29 29 28 0 0 0 0 28 29 28 29 29 28 29 29 

3. Backwater Mean 0.2 0.96 0.05 — — — — 24.8 10.3 126 406 8.2 44.4 22 34.3  Median 0.2 0.66 0.01 — — — — 24.9 10.4 125 408 8.3 43 19 26.9  Minimum 0.1 0.14 0 — — — — 20 2.3 27 336 6.9 22 2 2.9  Maximum 0.2 6.5 0.41 — — — — 29.9 16.8 205 470 8.9 95 59 155  Std. dev. 0.01 1 0.08 — — — — 1.82 2.75 36.1 26 0.44 13.2 10.8 27.8 

N obs. 60 60 57 0 0 0 0 60 60 60 60 60 50 60 57 
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-surface measurements: summer

5. Impounded Mean 0.2 1.04 0.12 — — — — 25.1 10.5 128 402 8.4 41.5 23 33.9  Median 0.2 1 0.11 — — — — 25.2 10.6 129 401 8.4 42 20 28.2  Minimum 0.2 0.3 0.01 — — — — 23.2 8.3 100 392 8 24 14 18.2  Maximum 0.2 2 0.29 — — — — 27 13.2 168 419 8.9 57 41 82.7  Std. dev. 0 0.43 0.07 — — — — 0.9 1.4 18.9 8.57 0.23 8.79 7.35 15 

N obs. 25 25 24 0 0 0 0 25 25 25 25 25 25 25 25 

6. Isolated Mean 0.2 1.27 0 — — — — 22.6 1.91 23 603 7.6 47.1 8 21.4  Median 0.2 0.55 0 — — — — 22.3 0.75 8 545 7.4 35 7 24.8  Minimum 0.2 0.38 0 — — — — 20.3 0.2 2 412 6.6 20 3 1.9  Maximum 0.2 7.7 0.04 — — — — 25 7.8 95 1068 10.1 160 17 39.4  Std. dev. 0 2.26 0.01 — — — — 1.76 2.61 31.8 230 1.14 40.8 5.46 14.9 

N obs. 10 10 10 0 0 0 0 10 10 10 10 10 10 10 10 

1994 Middepth measurements: summer

3. Backwater Mean 1.63 3.34 — — — — — 22.9 7.47 89 429 8 — 15 16.9  Median 1.4 2.81 — — — — — 23.4 7.85 93 434 8.2 — 16 16.9  Minimum 0.7 1.4 — — — — — 19.4 0.3 3 399 7 — 9 6.2  Maximum 3.2 6.5 — — — — — 24.4 12.8 152 450 8.4 — 18 27.6  Std. dev. 0.9 1.84 — — — — — 1.84 4.03 47.9 24.1 0.65 — 4.04 15.1 

N obs. 6 6 0 — — — — 6 6 6 4 4 — 4 2 

1994 Near-bottom measurements: summer

3. Backwater Mean 2.79 2.98 — — — — — 20.7 5.2 61 454 7.6 — 26 26.8  Median 2.5 2.68 — — — — — 22.8 6.1 72 421 7.6 — 11 28.7  Minimum 0.7 0.85 — — — — — 11 0.2 2 418 6.8 — 4 14.2  Maximum 6.3 6.5 — — — — — 24 9.6 112 539 8.7 — 77 37.4  Std. dev. 1.92 1.93 — — — — — 4.8 3.71 43.6 52.8 0.81 — 34.4 11.7 

N obs. 7 7 0 — — — — 7 7 7 5 5 — 4 3 

6. Isolated Mean 2.2 2.41 — — — — — 18.7 0.98 12 — — — — —  Median 0.5 0.7 — — — — — 20.6 0.25 3 — — — — —  Minimum 0.3 0.54 — — — — — 9.2 0.2 2 — — — — —  Maximum 7.5 7.7 — — — — — 24.6 3.2 39 — — — — —  Std. dev. 3.54 3.53 — — — — — 6.64 1.48 18.2 — — — — — 

N obs. 4 4 0 — — — — 4 4 4 0 0 — 0 0 
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

1. Main channel Mean 0.2 4.08 0.41 — — — — 13.2 9.48 90 400 8.1 51.4 17 20.1  Median 0.2 3.66 0.42 — — — — 13.2 9.5 90 409 8.1 50 18 20.6  Minimum 0.2 0.95 0.11 — — — — 12.3 9.1 87 349 7.9 42 12 13.1  Maximum 0.2 7.98 0.72 — — — — 14.2 9.9 96 434 8.3 70 21 25.9  Std. dev. 0 1.79 0.18 — — — — 0.52 0.24 2.37 21.1 0.14 6.67 2.39 3.03 

N obs. 26 26 26 0 0 0 0 26 26 26 26 26 26 26 26 

2. Side channel Mean 0.2 2.3 0.3 — — — — 13.4 9.55 91 387 8.1 51.9 17 20.4  Median 0.2 1.91 0.31 — — — — 13.4 9.6 90 389 8.1 51 16 18  Minimum 0.2 0.35 0 — — — — 11.7 8.9 82 325 7.8 37 11 10.2  Maximum 0.2 5.6 0.65 — — — — 15.1 10.4 103 417 8.3 65 27 42.8  Std. dev. 0 1.43 0.17 — — — — 0.58 0.33 3.86 18.6 0.14 7.38 3.55 7.21 

N obs. 31 31 31 0 0 0 0 31 31 31 31 31 30 31 30 

3. Backwater Mean 0.2 0.93 0.08 — — — — 13.9 9.67 94 381 8.1 50.8 17 20.9  Median 0.2 0.71 0 — — — — 13.8 9.65 93 386 8.1 50 16 19.2  Minimum 0.2 0.26 0 — — — — 10.7 6.7 66 245 7.5 27 8 0.5  Maximum 0.2 7.01 0.42 — — — — 16.4 13.3 134 493 8.7 85 31 55.8  Std. dev. 0 0.96 0.12 — — — — 1.1 1.17 11.9 43.5 0.26 11.5 4.63 9.54 

N obs. 58 58 58 0 0 0 0 58 58 58 58 58 42 58 57 

5. Impounded Mean 0.2 1.18 0.17 — — — — 13.2 9.71 93 386 8.2 45.8 18 21.9  Median 0.2 0.93 0.13 — — — — 13.1 9.7 92 389 8.2 48 17 22.1  Minimum 0.2 0.45 0.06 — — — — 12.1 9.2 88 360 7.9 32 14 1.7  Maximum 0.2 3.8 0.43 — — — — 15.1 10.3 101 404 8.3 55 24 33.6  Std. dev. 0 0.71 0.08 — — — — 0.72 0.31 3.9 13.7 0.13 5.98 3.1 6.77 

N obs. 25 25 25 0 0 0 0 25 25 25 25 25 25 25 25 

6. Isolated Mean 0.2 0.68 0 — — — — 17 5.34 55 703 7.5 54.6 13 26.9  Median 0.2 0.61 0 — — — — 17.4 5.2 54 588 7.5 44 14 23.2  Minimum 0.2 0.36 0 — — — — 14.5 3.3 35 537 7.2 30 5 7.1  Maximum 0.2 1.15 0 — — — — 18.2 8.2 80 989 8.3 80 23 63.4  Std. dev. 0 0.24 0 — — — — 1.09 1.33 12.5 194 0.3 23.3 7.5 21.2 

N obs. 10 10 10 0 0 0 0 10 10 10 10 10 5 10 10 
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 Middepth measurements: fall

3. Backwater Mean 2.72 4.86 — — — — — 13.7 8.53 83 386 7.9 — 14 —  Median 2.55 4.93 — — — — — 13.6 7.8 75 386 7.8 — 12 —  Minimum 1 2.42 — — — — — 13.1 7.1 68 329 7.4 — 12 —  Maximum 5.1 7.01 — — — — — 14.9 12.2 121 443 8.6 — 17 —  Std. dev. 1.68 2.37 — — — — — 0.73 1.99 20.8 61 0.49 — 2.89 — 

N obs. 6 6 0 — — — — 6 6 6 6 6 — 3 0 

1994 Near-bottom measurements: fall

3. Backwater Mean 2.26 2.56 — — — — — 14.5 8.36 82 398 8.2 — 18 —  Median 2 2.24 — — — — — 15 9 90 395 8.3 — 18 —  Minimum 0.8 0.96 — — — — — 13.1 6.6 63 331 7.5 — 14 —  Maximum 6.2 7.01 — — — — — 15.4 9.7 96 442 8.7 — 23 —  Std. dev. 1.88 2.09 — — — — — 0.89 1.13 12.5 39.5 0.38 — 4.69 — 

N obs. 7 7 0 — — — — 7 7 7 7 7 — 4 0 

6. Isolated Mean 0.65 0.88 — — — — — 14.8 6.65 65 572 7.9 — 6 —  Median 0.65 0.88 — — — — — 14.8 6.65 65 572 7.9 — 6 —  Minimum 0.5 0.75 — — — — — 14.2 5.3 53 547 7.5 — 6 —  Maximum 0.8 1 — — — — — 15.3 8 78 597 8.3 — 6 —  Std. dev. 0.21 0.18 — — — — — 0.78 1.91 17.7 35.4 0.57 — — — 

N obs. 2 2 0 — — — — 2 2 2 2 2 — 1 0 

1994 Other measurements: fall

3. Backwater Mean 1.5 7.01 — — — — — 13.1 7.3 69 380 7.5 — — —  Median 1.5 7.01 — — — — — 13.1 7.3 69 380 7.5 — — —  Minimum 1.5 7.01 — — — — — 13.1 7.3 69 380 7.5 — — —  Maximum 1.5 7.01 — — — — — 13.1 7.3 69 380 7.5 — — —  Std. dev. — — — — — — — — — — — — — — — 

N obs. 1 1 0 — — — — 1 1 1 1 1 — 0 0 
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

1. Main channel Mean 0.2 4.24 0.23 95.2 21 70 1 -.01 15.1 103 468 8.4 124 3 4.1  Median 0.2 4.21 0.21 100 20 80 1 0 15.1 103 466 8.4 127 3 4  Minimum 0.2 0.82 0.06 60 6 5 0 -0.1 14 96 443 8.3 87 2 3.1  Maximum 0.2 7.7 0.54 100 38 100 3 0.1 16.7 114 491 8.5 150 6 5.5  Std. dev. 0 1.93 0.12 9.94 8.17 29.7 .95 0.08 0.65 4.45 13.7 0.06 15.8 1.09 0.57 

N obs. 24 24 23 22 22 22 21 24 24 24 24 24 23 24 24 

2. Side channel Mean 0.19 1.96 0.13 97.8 21 77 2 0.13 15 103 464 8.5 119 6 13.7  Median 0.2 1.75 0.11 100 20 97 2 0.1 15.1 104 447 8.5 120 4 4  Minimum 0 0.32 0 50 7 0 0 -0.1 12 83 436 8.4 51 2 3.2  Maximum 0.2 5.04 0.27 100 39 100 4 0.6 16.2 111 576 8.6 159 59 262  Std. dev. 0.05 1.3 0.07 10.2 10.2 31.7 1.1 0.14 0.87 5.86 33.5 0.07 22 10.7 49.5 

N obs. 27 27 25 24 24 24 24 27 27 27 27 27 19 27 27 

3. Backwater Mean 0.18 0.84 0.05 99.7 32 90 2 0.24 16.1 111 475 8.5 87.1 5 7.5  Median 0.2 0.68 0.01 100 35 100 2 0.1 15.5 106 450 8.5 92.5 5 4.5  Minimum 0 0.33 0 90 15 40 0 -0.1 11 77 397 7.6 48 2 3.1  Maximum 0.2 4.22 0.26 100 49 100 6 0.8 22.2 155 762 8.8 121 13 25.5  Std. dev. 0.05 0.68 0.07 1.74 8.72 19.5 1.3 0.24 2.44 17.1 69.9 0.25 29 2.5 5.98 

N obs. 33 33 29 33 33 33 32 33 33 33 33 33 8 31 32 

5. Impounded Mean 0.2 1.46 0.09 100 31 85 1 0.04 16.1 110 459 8.5 118 3 3.8  Median 0.2 1.39 0.08 100 30 90 1 0 16 109 457 8.5 115 3 4  Minimum 0.2 0.44 0.03 100 24 50 0 -0.1 14.8 101 432 8.4 96 1 2  Maximum 0.2 3.07 0.19 100 43 100 3 0.2 17.8 122 499 8.6 143 4 4.6  Std. dev. 0 0.63 0.04 0 4.55 14.1 .87 0.09 0.87 6.18 17.6 0.09 14.9 0.76 0.66 

N obs. 24 24 22 24 24 24 24 24 24 24 24 24 15 24 24 

6. Isolated Mean 0.15 2.22 0 100 34 81 1 1.28 9.98 70 1303 7.7 54 14 12.7  Median 0.15 0.69 0 100 35 98 1 0.95 9.35 66 1122 7.7 54 13 13.1  Minimum 0.1 0.5 0 100 30 30 1 0.5 1.2 9 895 6.7 43 7 5.4  Maximum 0.2 7 0 100 37 100 1 2.7 20 140 2071 8.7 65 22 19.1  Std. dev. 0.06 3.19 0 0 2.94 34.2 0 0.97 9.77 68.5 525 0.9 15.6 6.35 5.61 

N obs. 4 4 3 4 4 4 4 4 4 4 4 4 2 4 4 
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 Middepth measurements: winter

6. Isolated Mean 1.95 3.94 — — — — — 2.2 11.4 81 1199 7.8 — — —  Median 1.95 3.94 — — — — — 2.2 11.4 81 1199 7.8 — — —  Minimum 0.4 0.87 — — — — — 1.2 2.8 21 1188 6.9 — — —  Maximum 3.5 7 — — — — — 3.2 20 141 1210 8.6 — — —  Std. dev. 2.19 4.33 — — — — — 1.41 12.2 85.2 15.6 1.2 — — — 

N obs. 2 2 0 — — — — 2 2 2 2 2 — 0 0 

1995 Near-bottom measurements: winter

6. Isolated Mean 6.8 7 — — — — — 3.2 2.8 21 1365 6.8 — 74 19.5  Median 6.8 7 — — — — — 3.2 2.8 21 1365 6.8 — 74 19.5  Minimum 6.8 7 — — — — — 3.2 2.8 21 1365 6.8 — 74 19.5  Maximum 6.8 7 — — — — — 3.2 2.8 21 1365 6.8 — 74 19.5  Std. dev. — — — — — — — — — — — — — — — 

N obs. 1 1 0 — — — — 1 1 1 1 1 — 1 1 

1995 Near-surface measurements: spring

1. Main channel Mean 0.2 4.38 0.75 — — — — 12.4 12.6 118 506 8.8 60.4 15 26.9  Median 0.2 3.9 0.79 — — — — 12.4 12.1 115 502 8.8 60 15 26.3  Minimum 0.2 1.31 0 — — — — 11 10.5 97 428 8.7 46 11 17.7  Maximum 0.2 9.6 1.12 — — — — 13.7 17.1 164 553 9 69 21 41.3  Std. dev. 0 2.35 0.26 — — — — 0.66 2.06 19.1 35.9 0.13 5.41 2.25 4.56 

N obs. 25 25 25 0 0 0 0 25 25 25 25 25 25 25 25 

2. Side channel Mean 0.2 2.33 0.48 — — — — 12.4 13.3 125 476 8.9 57.9 15 26.4  Median 0.2 1.64 0.53 — — — — 12.3 13.8 131 468 8.9 57 15 25.5  Minimum 0.2 0.59 0.1 — — — — 11.2 10.4 98 384 8.7 49 9 17.6  Maximum 0.2 5.4 0.8 — — — — 14.8 17.2 161 553 9.2 70 20 38.6  Std. dev. 0 1.46 0.18 — — — — 0.7 2.27 20.7 51.8 0.15 5.95 2.39 4.76 

N obs. 32 32 32 0 0 0 0 32 32 32 32 32 30 32 32 

3. Backwater Mean 0.2 1.01 0.11 — — — — 13.4 14.7 141 445 8.9 59.4 14 23.9  Median 0.2 0.96 0.02 — — — — 13 14.8 140 441 9 60 14 22.6  Minimum 0.2 0.24 0 — — — — 11.7 6.5 65 282 8.1 40 8 13  Maximum 0.2 2.67 0.6 — — — — 19.9 25 275 542 9.4 86 25 52.5  Std. dev. 0 0.48 0.18 — — — — 1.53 3.92 40.2 56.1 0.3 9.67 3.74 7.88 

N obs. 58 58 58 0 0 0 0 58 58 58 58 58 45 58 58 
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 1.67 0.29 — — — — 12.3 16 150 458 9 54.5 15 29.3  Median 0.2 1.55 0.3 — — — — 11.9 15.8 147 471 9 53 16 29.7  Minimum 0.2 0.56 0.04 — — — — 11.2 13.1 126 393 8.8 45 8 13  Maximum 0.2 4 0.49 — — — — 14.9 19.3 187 543 9.3 77 19 39.8  Std. dev. 0 0.92 0.11 — — — — 1.03 1.6 16.2 45.3 0.13 7.06 2.54 5.89 

N obs. 25 25 25 0 0 0 0 25 25 25 25 25 24 25 25 

6. Isolated Mean 0.2 1.28 0 — — — — 13.9 10.1 100 582 8.1 155 9 14.9  Median 0.2 0.59 0 — — — — 13.4 6.35 61 583 7.7 155 8 11.9  Minimum 0.2 0.5 0 — — — — 12.3 4.5 44 521 7.4 155 4 5  Maximum 0.2 7.15 0 — — — — 18.8 25 269 638 9.9 155 17 30.7  Std. dev. 0 2.07 0 — — — — 2.03 8.04 86 30.5 0.88 — 4.29 9.23 

N obs. 10 10 9 0 0 0 0 10 10 10 10 10 1 10 10 

1995 Middepth measurements: spring

6. Isolated Mean 3.5 7.15 — — — — — 11.1 1.68 16 563 7.5 — — —  Median 3.5 7.15 — — — — — 11.3 1.2 11 562 7.5 — — —  Minimum 2 7.15 — — — — — 8 0.1 1 538 7.3 — — —  Maximum 5 7.15 — — — — — 13.8 4.2 41 589 7.6 — — —  Std. dev. 1.29 0 — — — — — 2.5 1.98 19.1 22.4 0.13 — — — 

N obs. 4 4 0 — — — — 4 4 4 4 4 — 0 0 

1995 Near-bottom measurements: spring

6. Isolated Mean 6.5 7.15 — — — — — 5.6 0.1 1 905 7.2 — — —  Median 6.5 7.15 — — — — — 5.6 0.1 1 905 7.2 — — —  Minimum 6 7.15 — — — — — 4.8 0.1 1 663 7 — — —  Maximum 7 7.15 — — — — — 6.4 0.1 1 1147 7.3 — — —  Std. dev. 0.71 0 — — — — — 1.13 0 0.02 342 0.21 — — — 

N obs. 2 2 0 — — — — 2 2 2 2 2 — 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 Other measurements: spring

6. Isolated Mean 1 7.15 — — — — — 13.9 4.3 42 589 7.6 — — —  Median 1 7.15 — — — — — 13.9 4.3 42 589 7.6 — — —  Minimum 1 7.15 — — — — — 13.9 4.3 42 589 7.6 — — —  Maximum 1 7.15 — — — — — 13.9 4.3 42 589 7.6 — — —  Std. dev. — — — — — — — — — — — — — — — 

N obs. 1 1 0 — — — — 1 1 1 1 1 — 0 0 

1995 Near-surface measurements: summer

1. Main channel Mean 0.2 4.1 0.38 — — — — 27.1 9.39 120 486 8.6 59.9 16 22.6  Median 0.2 3.68 0.41 — — — — 27.3 9.15 117 483 8.6 60.5 16 22.5  Minimum 0.2 0.9 0.05 — — — — 25.4 7.9 98 464 8.4 35 12 13.1  Maximum 0.2 10.8 0.7 — — — — 28.1 11.3 146 514 8.7 76 25 37.9  Std. dev. 0 2.1 0.18 — — — — 0.77 0.85 12 17.4 0.08 11 2.9 5.63 

N obs. 26 26 26 0 0 0 0 26 26 26 26 26 26 26 26 

2. Side channel Mean 0.2 2.22 0.38 — — — — 27.2 9.64 123 477 8.6 57.6 16 23.2  Median 0.2 1.96 0.32 — — — — 27.6 9.05 116 480 8.6 58 16 23.4  Minimum 0.2 0.58 0.04 — — — — 25.7 8.2 102 404 8.5 39 10 10  Maximum 0.2 4.6 2.3 — — — — 29.4 13.9 185 503 8.9 72 29 49.3  Std. dev. 0 1.26 0.41 — — — — 1.05 1.37 19.5 22.6 0.1 8.51 3.65 7.33 

N obs. 28 28 27 0 0 0 0 28 28 28 28 28 27 28 28 

3. Backwater Mean 0.2 0.75 0.07 — — — — 27.7 10.3 133 469 8.5 42.9 22 36.5  Median 0.2 0.58 0.02 — — — — 27.5 9.8 124 475 8.6 43 19 28.6  Minimum 0.2 0.24 0 — — — — 24 3.9 50 304 7.3 17 11 13.9  Maximum 0.2 3.2 0.46 — — — — 32.1 25 351 521 9 70 56 316  Std. dev. 0 0.57 0.11 — — — — 1.74 3.28 47.2 38.3 0.3 12.3 9.72 40.8 

N obs. 59 59 58 0 0 0 0 59 59 59 59 59 41 58 59 

5. Impounded Mean 0.2 1.53 0.16 — — — — 27.2 10 128 494 8.6 44.3 20 27.3  Median 0.2 1.28 0.16 — — — — 27.1 10 127 495 8.6 43 19 26.7  Minimum 0.2 0.53 0 — — — — 25.5 7.8 97 475 8.4 35 13 15  Maximum 0.2 6.3 0.4 — — — — 30.4 13.2 177 510 8.8 56 28 43  Std. dev. 0 1.06 0.08 — — — — 1.17 1.25 18.8 7.88 0.1 5.55 3.74 6.85 

N obs. 27 27 27 0 0 0 0 27 27 27 27 27 27 27 27 
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 Near-surface measurements: summer

6. Isolated Mean 0.2 1.55 0 — — — — 24.1 4.1 50 840 7.7 124 17 43.1  Median 0.2 0.5 0 — — — — 24.3 2 24 760 7.6 124 21 19.4  Minimum 0.2 0.35 0 — — — — 21.7 0.2 2 553 7 113 3 3.2  Maximum 0.2 6.71 0 — — — — 26.3 13.9 172 1374 9.4 135 50 246  Std. dev. 0 2.28 0 — — — — 1.93 4.25 53 317 0.72 15.6 15.8 77.7 

N obs. 10 10 9 0 0 0 0 9 9 9 9 9 2 9 9 

1995 Middepth measurements: summer

6. Isolated Mean 3.5 6.71 — — — — — 18.7 0.28 3 597 7.3 — — —  Median 3.5 6.71 — — — — — 18.8 0.1 1 599 7.3 — — —  Minimum 2 6.71 — — — — — 12.5 0.1 1 557 7.1 — — —  Maximum 5 6.71 — — — — — 24.9 0.8 10 635 7.5 — — —  Std. dev. 1.29 0 — — — — — 5.61 0.35 4.36 35.3 0.17 — — — 

N obs. 4 4 0 — — — — 4 4 4 4 4 — 0 0 

1995 Near-bottom measurements: summer

6. Isolated Mean 6.5 6.71 — — — — — 10.1 0.1 1 689 6.9 — 7 35  Median 6.5 6.71 — — — — — 10.1 0.1 1 689 6.9 — 7 35  Minimum 6.5 6.71 — — — — — 10.1 0.1 1 689 6.9 — 7 35  Maximum 6.5 6.71 — — — — — 10.1 0.1 1 689 6.9 — 7 35  Std. dev. — — — — — — — — — — — — — — — 

N obs. 1 1 0 — — — — 1 1 1 1 1 — 1 1 

1995 Other measurements: summer

6. Isolated Mean 1.25 6.71 — — — — — 25.5 3.2 39 553 7.6 — — —  Median 1.25 6.71 — — — — — 25.5 3.2 39 553 7.6 — — —  Minimum 1 6.71 — — — — — 25.3 2.3 28 552 7.5 — — —  Maximum 1.5 6.71 — — — — — 25.7 4.1 51 554 7.7 — — —  Std. dev. 0.35 0 — — — — — 0.28 1.27 15.9 1.41 0.14 — — — 

N obs. 2 2 0 — — — — 2 2 2 2 2 — 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-surface measurements: fall

1. Main channel Mean 0.2 4.44 0.58 — — — — 13.1 9.71 92 358 8.3 52.5 19 26.6  Median 0.2 3.1 0.6 — — — — 13.2 9.7 92 360 8.3 51 19 25.3  Minimum 0.2 0.51 0.17 — — — — 11.4 9 88 325 8.1 44 13 17.5  Maximum 0.2 9.1 0.88 — — — — 14.5 10.2 97 388 8.5 71 22 35.1  Std. dev. 0 2.45 0.23 — — — — 0.85 0.28 2.55 20 0.12 6.01 2.1 4.61 

N obs. 25 25 25 0 0 0 0 25 25 25 25 25 24 25 25 

2. Side channel Mean 0.2 2.61 0.43 — — — — 13.3 9.59 92 334 8.2 51.8 18 24.9  Median 0.2 2.28 0.44 — — — — 13.3 9.6 91 334 8.2 50 18 22.5  Minimum 0.2 0.65 0 — — — — 10.9 9 83 230 7.8 42 10 8.9  Maximum 0.2 6.5 0.76 — — — — 16.1 10.1 102 388 8.5 74 27 40.9  Std. dev. 0 1.48 0.17 — — — — 1.45 0.29 3.72 36.7 0.14 7.46 3.66 7.82 

N obs. 30 30 30 0 0 0 0 30 30 30 30 30 28 30 30 

3. Backwater Mean 0.2 1.06 0.09 — — — — 14 9.85 96 335 8.3 49.2 17 24.9  Median 0.2 0.91 0 — — — — 14 9.7 95 328 8.3 46 16 21.8  Minimum 0.2 0.34 0 — — — — 9.2 3.6 35 127 7.4 31 2 2.7  Maximum 0.2 4.2 0.69 — — — — 17.5 14.1 140 494 9.2 85 42 62.3  Std. dev. 0 0.64 0.16 — — — — 1.96 1.83 19.3 65.5 0.39 11.6 7.93 14.1 

N obs. 60 60 60 0 0 0 0 60 60 60 60 60 47 60 60 

5. Impounded Mean 0.2 1.48 0.21 — — — — 14.5 9.94 98 335 8.4 45.8 19 29.3  Median 0.2 1.33 0.21 — — — — 14.8 9.8 98 326 8.4 46 18 28.7  Minimum 0.2 0.5 0.08 — — — — 12.9 9.1 88 276 8.2 38 15 21.1  Maximum 0.2 3.9 0.46 — — — — 16.3 11.2 107 380 8.7 56 26 41.5  Std. dev. 0 0.68 0.07 — — — — 1.23 0.57 5.38 23.9 0.14 5.03 3.23 5.24 

N obs. 25 25 25 0 0 0 0 25 25 25 25 25 25 25 25 

6. Isolated Mean 0.2 0.51 0 — — — — 9.83 5.08 45 822 7.7 75 5 5.7  Median 0.2 0.47 0 — — — — 8.95 4.35 37 817 7.7 75 5 5.2  Minimum 0.2 0.35 0 — — — — 7.9 2.1 18 538 7.4 75 2 2.4  Maximum 0.2 0.9 0 — — — — 13.5 8.9 85 1163 8.3 75 12 11.7  Std. dev. 0 0.17 0 — — — — 1.92 2.65 24.4 227 0.33 — 2.82 3.07 

N obs. 10 10 10 0 0 0 0 10 10 10 10 10 1 10 10 
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-bottom measurements: fall

2. Side channel Mean 1.4 1.6 — — — — — 11.7 9 83 324 8 — — —  Median 1.4 1.6 — — — — — 11.7 9 83 324 8 — — —  Minimum 1.4 1.6 — — — — — 11.7 9 83 324 8 — — —  Maximum 1.4 1.6 — — — — — 11.7 9 83 324 8 — — —  Std. dev. — — — — — — — — — — — — — — — 

N obs. 1 1 0 — — — — 1 1 1 1 1 — 0 0 

3. Backwater Mean 0.89 1.08 — — — — — 13.6 10.3 99 360 8.4 — — —  Median 0.75 0.95 — — — — — 13.9 10.3 97 357 8.4 — — —  Minimum 0.4 0.59 — — — — — 9.2 4.6 44 153 7.4 — — —  Maximum 4 4.2 — — — — — 17.5 14 140 494 9.2 — — —  Std. dev. 0.64 0.65 — — — — — 2.49 1.85 20.5 70.2 0.44 — — — 

N obs. 28 28 0 — — — — 28 28 28 28 28 — 0 0 

6. Isolated Mean 0.35 0.55 — — — — — 8.75 3.9 33 1108 7.7 — — —  Median 0.35 0.55 — — — — — 8.75 3.9 33 1108 7.7 — — —  Minimum 0.3 0.5 — — — — — 8.6 0.2 2 1054 7.4 — — —  Maximum 0.4 0.6 — — — — — 8.9 7.6 65 1162 7.9 — — —  Std. dev. 0.07 0.07 — — — — — 0.21 5.23 44.8 76.4 0.35 — — — 

N obs. 2 2 0 — — — — 2 2 2 2 2 — 0 0 

1996 Near-surface measurements: winter

1. Main channel Mean 0.2 3.91 0.24 99.8 32 99 12 0.01 9.62 66 437 7.7 154 3 2.3  Median 0.2 4 0.26 100 32 100 11 0 9.6 66 437 7.7 153 3 1.9  Minimum 0.2 0.6 0.05 95 13 95 0 0 8.8 60 402 7.5 107 2 1.4  Maximum 0.2 9.45 0.4 100 55 100 31 0.2 10.6 72 481 7.9 268 4 6.2  Std. dev. 0 2.19 0.08 1 7.99 1.91 9.7 0.04 0.39 2.67 19.3 0.11 37.2 0.71 1.16 

N obs. 25 25 25 25 25 25 25 25 25 25 25 25 21 25 25 

2. Side channel Mean 0.2 2.34 0.15 100 38 95 10 0.01 9.3 64 435 7.7 135 3 2.3  Median 0.2 2.25 0.16 100 41 100 9 0 9.3 64 430 7.7 136 3 2.3  Minimum 0.2 0.68 0 99 18 20 0 0 8.3 57 407 7.3 62 2 1.3  Maximum 0.2 4.3 0.26 100 57 100 29 0.1 10.3 70 468 8 168 4 3.7  Std. dev. 0 1.11 0.06 0.19 10.1 18.2 7.7 0.04 0.4 2.75 18 0.16 25.2 0.71 0.65 

N obs. 29 29 29 29 29 29 29 29 29 29 29 29 19 29 29 
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

3. Backwater Mean 0.14 0.96 0.06 99.9 42 92 12 0.15 6.82 47 489 7.6 85.7 10 8  Median 0.2 0.76 0.01 100 43 100 12 0.1 8.7 59 426 7.6 77.5 4 2.7  Minimum 0 0.42 0 95 19 20 0 -0.1 0 0 341 7 24 2 -0.1  Maximum 0.2 4.27 0.28 100 60 100 35 1 10.2 70 1011 7.8 204 120 107  Std. dev. 0.08 0.69 0.08 0.73 7.13 20.9 9.7 0.25 3.65 25 154 0.25 42.5 20.9 19.1 

N obs. 49 49 35 48 48 48 44 49 49 49 49 49 18 41 42 

5. Impounded Mean 0.2 1.47 0.1 100 42 100 17 0 9.37 64 429 7.8 125 3 1.9  Median 0.2 1.26 0.1 100 44 100 18 0 9.45 65 437 7.8 122 3 1.8  Minimum 0.1 0.72 0.01 100 26 100 7 0 8.1 55 250 7.6 97 3 1.2  Maximum 0.2 4 0.15 100 48 100 24 0 9.7 66 462 8.1 146 4 3.2  Std. dev. 0.02 0.76 0.03 0 6.01 0 4.3 0 0.41 2.8 42.5 0.16 16.6 0.49 0.41 

N obs. 22 22 22 22 22 22 22 22 22 22 22 22 9 22 22 

6. Isolated Mean 0.11 0.58 0 99.9 35 100 17 0.46 0.6 4 1401 7.1 37 42 36.3  Median 0.1 0.64 0 100 37 100 24 0.3 0.5 4 1214 7 36 39 26.3  Minimum 0 0.42 0 99 15 100 5 -0.1 0.2 1 671 6.9 30 19 22  Maximum 0.2 0.68 0 100 43 100 27 1.5 1.3 9 2230 7.3 46 77 63.3  Std. dev. 0.09 0.11 0 0.38 10 0 10 0.56 0.34 2.32 638 0.2 8.25 21.6 18.1 

N obs. 7 7 6 7 7 7 7 7 7 7 7 7 4 5 5 

1996 Middepth measurements: winter

3. Backwater Mean 0.77 1.67 — — — — — 0.37 7.53 52 392 7.6 — — —  Median 0.4 1.06 — — — — — 0.1 8.3 57 411 7.8 — — —  Minimum 0.4 1 — — — — — 0 6 42 355 7.3 — — —  Maximum 1.5 2.95 — — — — — 1 8.3 57 411 7.8 — — —  Std. dev. 0.64 1.11 — — — — — 0.55 1.33 8.44 32.3 0.29 — — — 

N obs. 3 3 0 — — — — 3 3 3 3 3 — 0 0 

1996 Near-bottom measurements: winter

2. Side channel Mean 1 1.2 — — — — — 0 9.1 62 419 7.8 — — —  Median 1 1.2 — — — — — 0 9.1 62 419 7.8 — — —  Minimum 1 1.2 — — — — — 0 9.1 62 419 7.8 — — —  Maximum 1 1.2 — — — — — 0 9.1 62 419 7.8 — — —  Std. dev. — — — — — — — — — — — — — — — 

N obs. 1 1 0 — — — — 1 1 1 1 1 — 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

3. Backwater Mean 1.43 1.62 — — — — — 0.43 7.07 49 433 7.6 — 9 4.6  Median 1.2 1.4 — — — — — 0.2 8.9 61 446 7.6 — 9 4.6  Minimum 0.7 0.9 — — — — — 0.1 1.2 9 332 7.2 — 9 4.6  Maximum 2.8 2.95 — — — — — 1.4 9.6 66 524 7.7 — 9 4.6  Std. dev. 0.75 0.74 — — — — — 0.48 3.12 21.2 60.5 0.19 — — — 

N obs. 7 7 0 — — — — 7 7 7 7 7 — 1 1 

1996 Near-surface measurements: spring

1. Main channel Mean 0.2 4.91 0.82 — — — — 9.42 11.8 103 253 8.4 67.8 15 24.9  Median 0.2 4.6 0.8 — — — — 9.3 11.8 103 254 8.4 68 13 21.6  Minimum 0.2 1.65 0.31 — — — — 8.5 11.2 96 204 8 53 11 16.2  Maximum 0.2 8.3 1.42 — — — — 11.1 12.6 115 296 8.8 76 25 50.5  Std. dev. 0 1.96 0.3 — — — — 0.71 0.32 3.76 25.1 0.19 6.32 3.88 8.86 

N obs. 25 25 24 0 0 0 0 25 25 25 25 25 25 25 25 

2. Side channel Mean 0.2 3 0.63 — — — — 9.82 12.1 107 243 8.5 64.5 15 25.7  Median 0.2 2.96 0.65 — — — — 9.7 12.1 107 230 8.5 65 13 20.6  Minimum 0.2 0.94 0.11 — — — — 8.6 10.9 97 193 8 50 11 1.9  Maximum 0.2 6.4 1.2 — — — — 11 13.2 119 295 8.9 79 29 58.1  Std. dev. 0 1.3 0.27 — — — — 0.75 0.59 6.38 31.1 0.24 7.98 4.28 12.1 

N obs. 31 31 31 0 0 0 0 31 30 30 31 31 31 31 31 

3. Backwater Mean 0.2 1.91 0.16 — — — — 9.91 12.8 113 259 8.6 74.3 10 15.2  Median 0.2 1.43 0.07 — — — — 10 12.6 112 238 8.6 71 10 13.3  Minimum 0.2 0.48 0 — — — — 7.8 11.1 96 185 8 38 3 -0.1  Maximum 0.2 13.2 0.75 — — — — 11.3 14.9 136 489 9.5 131 22 49.3  Std. dev. 0 1.72 0.2 — — — — 0.93 0.89 9.25 66.9 0.24 14.8 3.78 7.89 

N obs. 59 59 58 0 0 0 0 59 59 59 59 59 55 59 59 

5. Impounded Mean 0.2 1.73 0.35 — — — — 10.1 12.2 108 249 8.6 61.5 16 30.6  Median 0.2 1.65 0.35 — — — — 10.3 12.2 108 259 8.7 62 15 26.8  Minimum 0.2 0.9 0.12 — — — — 9 11.1 97 192 8 52 9 19.3  Maximum 0.2 2.74 0.6 — — — — 11.2 13.3 120 304 8.8 70 30 74.2  Std. dev. 0 0.47 0.11 — — — — 0.65 0.55 5.84 30.3 0.26 5.44 4.38 13.1 

N obs. 25 25 25 0 0 0 0 25 25 25 25 25 25 25 25 
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

6. Isolated Mean 0.2 2.03 0 — — — — 12.6 18 170 289 9.4 57.7 10 19.7  Median 0.2 1.32 0 — — — — 12.6 19.5 188 290 9.5 57 9 18.6  Minimum 0.2 1.06 0 — — — — 11.4 2.5 24 277 8.8 50 8 13.2  Maximum 0.2 8.84 0 — — — — 14 25 237 302 9.7 69 14 28.5  Std. dev. 0 2.4 0 — — — — 0.83 6.51 62.2 8.55 0.31 5.87 2.28 5.1 

N obs. 10 10 10 0 0 0 0 10 10 10 10 10 10 10 10 

1996 Middepth measurements: spring

6. Isolated Mean 4.4 8.84 — — — — — 10.6 12.2 110 280 8.6 — — —  Median 4.4 8.84 — — — — — 10.6 12.2 110 280 8.6 — — —  Minimum 4.4 8.84 — — — — — 10.6 12.2 110 280 8.6 — — —  Maximum 4.4 8.84 — — — — — 10.6 12.2 110 280 8.6 — — —  Std. dev. — — — — — — — — — — — — — — — 

N obs. 1 1 0 — — — — 1 1 1 1 1 — 0 0 

1996 Near-bottom measurements: spring

3. Backwater Mean 1.55 1.76 — — — — — 9.87 12.9 114 270 8.6 — — —  Median 1.4 1.56 — — — — — 10.2 13.2 117 247 8.6 — — —  Minimum 0.5 0.71 — — — — — 8.2 11.2 95 186 8 — — —  Maximum 3 3.2 — — — — — 11.1 15 136 488 9.5 — — —  Std. dev. 0.8 0.8 — — — — — 0.99 1.04 11.2 86.9 0.35 — — — 

N obs. 17 17 0 — — — — 17 17 17 17 17 — 0 0 

6. Isolated Mean 1.92 2.12 — — — — — 11.5 17.3 159 294 9.2 — 10 15.1  Median 1.1 1.33 — — — — — 11.6 18.8 178 297 9.3 — 10 15.1  Minimum 0.9 1.06 — — — — — 9.3 10.4 91 279 8.3 — 10 15.1  Maximum 8.6 8.84 — — — — — 13 20.7 193 315 9.7 — 10 15.1  Std. dev. 2.51 2.52 — — — — — 1.07 3.69 36.5 11.3 0.49 — — — 

N obs. 9 9 0 — — — — 9 9 9 9 9 — 1 1 
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-surface measurements: summer

1. Main channel Mean 0.2 4.65 0.38 — — — — 23.7 8.3 99 398 8.4 62.1 12 17.1  Median 0.2 4.5 0.32 — — — — 23.8 8.4 99 396 8.4 63 12 16.3  Minimum 0.2 1.2 0.14 — — — — 22.4 7.2 83 355 8.2 40 9 10.7  Maximum 0.2 8.9 0.69 — — — — 24.9 9.2 111 438 8.6 78 21 29.7  Std. dev. 0 2.2 0.18 — — — — 0.63 0.56 7.24 29.5 0.11 11.9 2.38 4.34 

N obs. 25 25 22 0 0 0 0 25 25 25 25 25 25 25 25 

2. Side channel Mean 0.2 2.09 0.27 — — — — 24 8.46 101 398 8.4 58.5 13 19.4  Median 0.2 1.61 0.23 — — — — 24.2 8.55 103 395 8.4 58 13 19  Minimum 0.2 0.42 0.1 — — — — 22.6 7.3 85 366 8.1 35 10 10.9  Maximum 0.2 5.3 0.52 — — — — 25 10.3 125 428 8.7 76 22 34.9  Std. dev. 0 1.43 0.12 — — — — 0.58 0.72 9.24 20.1 0.14 9.75 2.51 4.99 

N obs. 30 30 24 0 0 0 0 30 30 30 30 30 25 30 30 

3. Backwater Mean 0.18 0.66 0.04 — — — — 25 9.31 114 397 8.4 41.5 21 34.1  Median 0.2 0.5 0.01 — — — — 24.8 9.25 112 398 8.5 40 17 27  Minimum 0.1 0.22 0 — — — — 22 2.5 29 302 7.4 8 3 11  Maximum 0.2 5.18 0.25 — — — — 28.3 25 324 473 9.4 68 94 120  Std. dev. 0.04 0.82 0.06 — — — — 1.25 3.77 48.7 36.8 0.37 12.6 14.6 21.9 

N obs. 60 60 51 0 0 0 0 60 60 60 60 60 30 60 60 

5. Impounded Mean 0.2 1.53 0.13 — — — — 23.7 8.26 98 379 8.4 51.8 17 22.4  Median 0.2 1.45 0.12 — — — — 23.7 8.1 97 374 8.4 50 16 19.2  Minimum 0.2 0.5 0.06 — — — — 22.3 7.6 89 369 8.3 30 11 14.4  Maximum 0.2 3.3 0.26 — — — — 25.5 10.4 128 424 8.6 75 27 38.6  Std. dev. 0 0.73 0.05 — — — — 0.62 0.56 7.73 13.5 0.08 11.4 4.13 7 

N obs. 25 25 23 0 0 0 0 25 25 25 25 25 24 25 25 

6. Isolated Mean 0.2 1.22 0.01 — — — — 21.1 1.71 20 627 7.4 160 13 53.6  Median 0.2 0.55 0 — — — — 20.6 0.55 6 564 7.3 160 8 16.4  Minimum 0.2 0.29 0 — — — — 18.3 0.3 3 423 7.1 160 3 3.3  Maximum 0.2 7.9 0.06 — — — — 24.6 6.5 79 930 7.9 160 40 321  Std. dev. 0 2.35 0.02 — — — — 1.93 2.28 27.5 168 0.3 — 11.9 97.8 

N obs. 10 10 10 0 0 0 0 10 10 10 10 10 1 10 10 
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 Middepth measurements: summer

6. Isolated Mean 4.5 7.9 — — — — — 11.1 0.1 1 560 7.2 — 13 18.7  Median 4.5 7.9 — — — — — 11.1 0.1 1 560 7.2 — 13 18.7  Minimum 4 7.9 — — — — — 9.7 0.1 1 557 7.2 — 13 18.7  Maximum 5 7.9 — — — — — 12.4 0.1 1 563 7.2 — 13 18.7  Std. dev. 0.71 0 — — — — — 1.91 0 0.04 4.24 0 — — — 

N obs. 2 2 0 — — — — 2 2 2 2 2 — 1 1 

1996 Near-bottom measurements: summer

3. Backwater Mean 1.08 1.29 — — — — — 24.5 9.02 109 361 8.5 — — —  Median 0.7 0.88 — — — — — 24.4 9.1 108 344 8.4 — — —  Minimum 0.4 0.65 — — — — — 23.7 7.4 90 320 8.2 — — —  Maximum 5 5.18 — — — — — 25.3 11.4 139 425 8.9 — — —  Std. dev. 1.48 1.47 — — — — — 0.59 1.36 16.5 35.8 0.21 — — — 

N obs. 9 9 0 — — — — 9 9 9 9 9 — 0 0 

6. Isolated Mean 7.7 7.9 — — — — — 6.8 0.2 2 974 7 — 8 40.8  Median 7.7 7.9 — — — — — 6.8 0.2 2 974 7 — 8 40.8  Minimum 7.7 7.9 — — — — — 6.8 0.2 2 974 7 — 8 40.8  Maximum 7.7 7.9 — — — — — 6.8 0.2 2 974 7 — 8 40.8  Std. dev. — — — — — — — — — — — — — — — 

N obs. 1 1 0 — — — — 1 1 1 1 1 — 1 1 

1996 Near-surface measurements: fall

1. Main channel Mean 0.2 4.22 0.21 — — — — 13.3 15.4 147 347 9.3 56.9 13 24.9  Median 0.2 4.1 0.17 — — — — 13.6 14.8 143 343 9.2 58 11 20.9  Minimum 0.2 0.9 0.1 — — — — 12.1 12.2 115 331 9 35 7 15.4  Maximum 0.2 8 0.36 — — — — 14.2 18.2 175 362 9.6 72 22 41.2  Std. dev. 0 1.9 0.08 — — — — 0.64 2.2 22.2 8.71 0.22 10.6 4.97 8.68 

N obs. 25 25 23 0 0 0 0 25 25 25 25 25 25 25 25 

2. Side channel Mean 0.2 2.13 0.11 — — — — 13.2 15.8 151 342 9.3 56.3 14 27.5  Median 0.2 1.84 0.12 — — — — 13.4 15.4 145 342 9.3 57.5 12 24.4  Minimum 0.1 0.26 0 — — — — 11.6 12.6 121 302 9.1 34 8 16.4  Maximum 0.2 6 0.24 — — — — 15.6 25 245 363 9.7 75 23 54  Std. dev. 0.02 1.33 0.06 — — — — 0.8 2.43 24.8 11.2 0.16 10.7 4.37 9.24 

N obs. 30 30 28 0 0 0 0 30 30 30 30 30 28 30 30 
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/

1996 Near-surface measurements: fall

3. Backwater Mean 0.19 0.68 0.03 — — — — 13.2 15 144 356 9.2 48.3 15 29.5  Median 0.2 0.46 0.02 — — — — 13.2 15.2 143 343 9.3 45 13 24.1  Minimum 0.1 0.17 0 — — — — 10.8 6.8 64 307 7 23 1 1.3  Maximum 0.2 2.32 0.22 — — — — 17.2 25 255 499 9.9 68 111 243  Std. dev. 0.03 0.52 0.05 — — — — 1.22 3.66 37.6 36.6 0.49 11.9 14.7 35 

N obs. 60 60 60 0 0 0 0 60 60 60 60 60 26 60 60 

5. Impounded Mean 0.2 1.26 0.07 — — — — 13.5 17.2 165 342 9.4 47.7 21 45.9  Median 0.2 1.25 0.07 — — — — 13.5 16.9 162 342 9.3 45 19 34.6  Minimum 0.2 0.69 0.02 — — — — 12 13.8 132 327 9 31 10 21.3  Maximum 0.2 2.01 0.13 — — — — 15.4 25 250 360 9.8 66 50 145  Std. dev. 0 0.33 0.03 — — — — 0.62 2.73 28.5 8.57 0.21 9.95 9.42 29.6 

N obs. 25 25 24 0 0 0 0 25 25 25 25 25 25 25 25 

6. Isolated Mean 0.18 0.35 0 — — — — 10.5 7.37 66 990 7.8 — 7 9.7  Median 0.2 0.35 0 — — — — 10.7 8.35 75 874 7.8 — 5 7  Minimum 0.1 0.17 0 — — — — 8.3 1.9 18 566 7.3 — 3 5.6  Maximum 0.2 0.44 0 — — — — 12.6 10.6 100 1541 8.2 — 14 23.9  Std. dev. 0.04 0.09 0 — — — — 1.53 2.87 26.5 356 0.28 — 3.69 5.81 

N obs. 10 10 10 0 0 0 0 10 10 10 10 10 0 10 10 

1996 Middepth measurements: fall

3. Backwater Mean 0.7 1.46 — — — — — 12.1 15.2 141 400 9.2 — — —  Median 0.7 1.46 — — — — — 12.1 15.2 141 400 9.2 — — —  Minimum 0.7 1.46 — — — — — 12.1 15.2 141 400 9.2 — — —  Maximum 0.7 1.46 — — — — — 12.1 15.2 141 400 9.2 — — —  Std. dev. — — — — — — — — — — — — — — — 

N obs. 1 1 0 — — — — 1 1 1 1 1 — 0 0 

1996 Near-bottom measurements: fall

3. Backwater Mean 0.96 1.16 — — — — — 13.1 13.6 130 362 9 — 19 30.1  Median 0.95 1.15 — — — — — 13.3 14.2 132 358 9 — 19 30.1  Minimum 0.4 0.65 — — — — — 10.8 9.9 94 336 8.7 — 19 30.1  Maximum 1.5 1.73 — — — — — 14.2 16.3 159 422 9.3 — 19 30.1  Std. dev. 0.44 0.43 — — — — — 1.02 2.45 24 26.4 0.23 — — — 

N obs. 8 8 0 — — — — 8 8 8 8 8 — 1 1 
F-25

Table F-2. Summaries of chemical measurements during each stratified random sampling episode from 1993 through 1996. Data are gr

depth categories: near surface (less than 0.2 m below the surface), middepth, and near bottom (less than 0.2 m above the substrate).

Samplingstratum Statistic

Total nitrogen

(N mg/L)

Ammonium

 (N mg/L)

Nitrate–nitrite

 (N mg/L)

Total

phosphoru

s (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: summer

1. Main channel Mean 3.4 0.061 2.255 0.228 0.191 — — — — —  Median 3.341 0.058 2.167 0.229 0.191 — — — — —  Minimum 2.726 0.042 1.848 0.205 0.176 — — — — —  Maximum 4.156 0.08 2.794 0.252 0.204 — — — — —  Std. dev. 0.503 0.011 0.28 0.013 0.007 — — — — — 

N obs. 13 13 13 13 13 0 0 0 0 0 

2. Side channel Mean 3.514 0.062 2.218 0.228 0.189 — — — — —  Median 3.54 0.057 2.115 0.223 0.189 — — — — —  Minimum 2.545 0.043 1.778 0.198 0.178 — — — — —  Maximum 4.653 0.094 2.922 0.28 0.202 — — — — —  Std. dev. 0.572 0.013 0.356 0.02 0.007 — — — — — 

N obs. 16 16 16 16 16 0 0 0 0 0 

3. Backwater Mean 3.497 0.073 2.128 0.213 0.182 — — — — —  Median 3.296 0.064 2.096 0.211 0.187 — — — — —  Minimum 1.594 0.038 0.669 0.154 0.112 — — — — —  Maximum 11.32 0.311 3.768 0.311 0.278 — — — — —  Std. dev. 1.61 0.048 0.561 0.029 0.03 — — — — — 

N obs. 31 31 31 31 31 0 0 0 0 0 

5. Impounded Mean 3.482 0.061 2.299 0.223 0.193 — — — — —  Median 3.522 0.056 2.299 0.224 0.195 — — — — —  Minimum 2.092 0.045 1.858 0.198 0.18 — — — — —  Maximum 4.626 0.114 2.895 0.285 0.207 — — — — —  Std. dev. 0.774 0.019 0.32 0.022 0.008 — — — — — 

N obs. 13 13 13 13 13 0 0 0 0 0 

1993 Near-surface measurements: fall

1. Main channel Mean 4.39 0.043 1.626 0.174 0.113 — — — — —  Median 3.408 0.046 1.594 0.176 0.116 — — — — —  Minimum 2.764 -0.02 1.036 0.16 0.1 — — — — —  Maximum 14.74 0.067 2.056 0.189 0.12 — — — — —  Std. dev. 3.235 0.016 0.282 0.008 0.007 — — — — — 

N obs. 13 13 13 13 13 0 0 0 0 0 
F-26

Table F-2. Continued.

Samplingstratum 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

1993 Near-surface measurements: fall

2. Side channel Mean 3.508 0.052 1.479 0.173 0.106 — — — —  Median 3.458 0.052 1.428 0.17 0.107 — — — —  Minimum 2.467 -0.02 0.32 0.132 0.086 — — — —  Maximum 4.552 0.091 2.22 0.252 0.124 — — — —  Std. dev. 0.565 0.027 0.428 0.025 0.01 — — — — 

N obs. 16 16 16 16 16 0 0 0 0 

3. Backwater Mean 3.228 0.052 1.114 0.18 0.078 — — — —  Median 3.407 0.033 1.34 0.175 0.095 — — — —  Minimum 1.379 -0.02 -0.01 0.081 -0.01 — — — —  Maximum 4.519 0.169 2.199 0.285 0.122 — — — —  Std. dev. 0.809 0.043 0.737 0.037 0.039 — — — — 

N obs. 31 32 32 32 32 0 0 0 0 

5. Impounded Mean 3.361 0.047 1.7 0.176 0.109 — — — —  Median 3.316 0.042 1.769 0.173 0.109 — — — —  Minimum 2.464 -0.02 1.291 0.165 0.1 — — — —  Maximum 5.049 0.083 1.897 0.193 0.117 — — — —  Std. dev. 0.651 0.024 0.212 0.008 0.006 — — — — 

N obs. 12 12 12 12 12 0 0 0 0 

1994 Near-surface measurements: winter

1. Main channel Mean 2.316 0.438 1.962 0.116 — — — — —  Median 2.221 0.462 1.9 0.116 — — — — —  Minimum 1.99 0.275 1.8 0.098 — — — — —  Maximum 2.861 0.513 2.48 0.126 — — — — —  Std. dev. 0.258 0.078 0.174 0.008 — — — — — 

N obs. 12 12 12 12 0 0 0 0 0 

2. Side channel Mean 2.482 0.425 2.156 0.114 — — — — —  Median 2.366 0.436 1.98 0.114 — — — — —  Minimum 1.812 0.24 1.81 0.097 — — — — —  Maximum 4.121 0.567 3.85 0.134 — — — — —  Std. dev. 0.595 0.102 0.532 0.011 — — — — — 

N obs. 13 13 13 13 0 0 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: winter

3. Backwater Mean 2.708 0.4 1.717 0.109 — — — — —  Median 2.313 0.349 1.87 0.116 — — — — —  Minimum 0.836 0.177 0.51 0.056 — — — — —  Maximum 7.321 0.842 2.09 0.136 — — — — —  Std. dev. 1.617 0.149 0.48 0.025 — — — — — 

N obs. 16 16 16 16 0 0 0 0 0 

5. Impounded Mean 2.672 0.469 1.921 0.121 — — — — —  Median 2.32 0.447 1.94 0.116 — — — — —  Minimum 2.128 0.369 0.52 0.104 — — — — —  Maximum 5.936 0.705 2.38 0.152 — — — — —  Std. dev. 1.044 0.084 0.474 0.015 — — — — — 

N obs. 12 12 12 12 0 0 0 0 0 

1994 Near-surface measurements: spring

1. Main channel Mean 2.284 0.028 1.884 0.115 0.02 3.349 — — —  Median 2.305 -0.02 1.674 0.125 0.018 3.286 — — —  Minimum 1.263 -0.02 1.03 0.078 -0.01 1.592 — — —  Maximum 4.31 0.084 4.914 0.149 0.044 6.191 — — —  Std. dev. 0.71 0.025 0.938 0.025 0.015 1.013 — — — 

N obs. 13 13 13 13 13 13 0 0 0 

2. Side channel Mean 1.942 0.028 1.29 0.112 0.019 3.098 — — —  Median 1.813 -0.02 1.225 0.107 0.016 3.193 — — —  Minimum 1.173 -0.02 0.54 0.081 -0.01 1.974 — — —  Maximum 2.934 0.148 2.078 0.145 0.043 3.597 — — —  Std. dev. 0.376 0.04 0.326 0.025 0.012 0.385 — — — 

N obs. 16 16 16 16 16 16 0 0 0 

3. Backwater Mean 1.868 0.033 1.253 0.108 0.017 2.836 — — —  Median 1.813 -0.02 1.231 0.112 0.017 3.008 — — —  Minimum 0.766 -0.02 0.18 0.052 -0.01 0.389 — — —  Maximum 3.965 0.148 4.499 0.162 0.043 3.916 — — —  Std. dev. 0.647 0.038 0.753 0.029 0.012 0.722 — — — 

N obs. 32 32 32 32 32 32 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: spring

5. Impounded Mean 2.077 0.031 1.493 0.111 0.022 3.363 — — —  Median 2.102 0.02 1.597 0.114 0.025 3.333 — — —  Minimum 1.532 -0.02 0.98 0.078 -0.01 3.019 — — —  Maximum 2.522 0.115 1.909 0.152 0.035 3.905 — — —  Std. dev. 0.299 0.031 0.256 0.026 0.011 0.238 — — — 

N obs. 13 13 13 13 13 13 0 0 0 

6. Isolated Mean 1.508 0.019 0.566 0.071 0.019 1.515 — — —  Median 1.777 0.022 0.714 0.075 -0.01 1.555 — — —  Minimum 0.657 -0.02 0.241 0.049 -0.01 0.645 — — —  Maximum 2.009 0.027 0.843 0.084 0.076 1.991 — — —  Std. dev. 0.555 0.008 0.298 0.013 0.032 0.544 — — — 

N obs. 5 5 5 5 5 5 0 0 0 

1994 Near-surface measurements: summer

1. Main channel Mean 2.087 0.01 1.212 0.153 0.041 6.23 — — —  Median 2.119 -0.02 1.257 0.151 0.034 6.243 — — —  Minimum 1.109 -0.02 0.669 0.104 -0.01 4.54 — — —  Maximum 2.782 -0.02 1.529 0.204 0.101 7.62 — — —  Std. dev. 0.414 0 0.229 0.033 0.026 0.771 — — — 

N obs. 14 14 14 14 14 14 0 0 0 

2. Side channel Mean 1.951 0.011 1.122 0.144 0.071 5.928 — — —  Median 1.916 -0.02 1.062 0.14 0.05 6.014 — — —  Minimum 1.543 -0.02 0.814 0.105 -0.01 4.987 — — —  Maximum 3.176 0.02 1.495 0.201 0.334 6.845 — — —  Std. dev. 0.392 0.002 0.196 0.028 0.078 0.418 — — — 

N obs. 17 17 17 17 17 17 0 0 0 

3. Backwater Mean 1.484 0.015 0.766 0.134 0.049 5.963 — — —  Median 1.504 -0.02 0.822 0.122 0.046 5.743 — — —  Minimum 0.622 -0.02 -0.01 0.041 -0.01 4.127 — — —  Maximum 2.863 0.1 2.584 0.307 0.203 9.206 — — —  Std. dev. 0.512 0.017 0.534 0.055 0.037 0.912 — — — 

N obs. 32 32 32 32 32 32 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: summer

5. Impounded Mean 2.122 0.013 0.928 0.147 0.032 5.668 — — —  Median 2.188 -0.02 0.852 0.147 0.024 5.755 — — —  Minimum 1.543 -0.02 0.742 0.123 0.015 4.759 — — —  Maximum 2.461 0.035 1.292 0.171 0.082 6.228 — — —  Std. dev. 0.276 0.009 0.169 0.017 0.019 0.478 — — — 

N obs. 13 13 13 13 13 13 0 0 0 

6. Isolated Mean 1.579 0.015 0.005 0.455 0.14 1.831 — — —  Median 1.333 -0.02 -0.01 0.442 0.134 1.247 — — —  Minimum 0.885 -0.02 -0.01 0.102 0.037 -0.05 — — —  Maximum 2.924 0.036 -0.01 0.754 0.253 5.412 — — —  Std. dev. 0.785 0.012 0 0.235 0.099 2.083 — — — 

N obs. 5 5 5 5 5 5 0 0 0 

1994 Near-surface measurements: fall

1. Main channel Mean 2.345 0.011 1.842 0.19 0.084 6.676 — — —  Median 2.454 -0.02 1.9 0.151 0.08 6.631 — — —  Minimum 1.134 -0.02 1.507 0.132 0.061 6.342 — — —  Maximum 2.824 0.03 2.18 0.384 0.102 7.33 — — —  Std. dev. 0.437 0.005 0.223 0.072 0.015 0.279 — — — 

N obs. 14 14 14 14 14 14 0 0 0 

2. Side channel Mean 2.339 0.015 1.753 0.219 0.086 6.203 — — —  Median 2.327 -0.02 1.708 0.153 0.089 6.675 — — —  Minimum 1.767 -0.02 1.257 0.119 0.062 0.119 — — —  Maximum 2.996 0.035 3.355 0.702 0.116 7.553 — — —  Std. dev. 0.338 0.009 0.47 0.151 0.016 1.681 — — — 

N obs. 17 17 17 17 17 17 0 0 0 

3. Backwater Mean 1.979 0.021 1.205 0.208 0.062 5.861 — — —  Median 2.147 -0.02 1.52 0.15 0.066 6.7 — — —  Minimum 0.952 -0.02 -0.01 0.047 -0.01 0.259 — — —  Maximum 2.785 0.179 1.845 0.488 0.137 8.024 — — —  Std. dev. 0.53 0.033 0.592 0.131 0.036 2.019 — — — 

N obs. 30 30 30 30 30 30 0 0 0 
F-30

Table F-2. Continued.

Samplingstratum 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

5. Impounded Mean 2.215 0.011 1.55 0.256 0.071 6.751 — — —  Median 2.147 -0.02 1.566 0.233 0.068 6.704 — — —  Minimum 1.831 -0.02 1.239 0.143 0.047 5.523 — — —  Maximum 2.705 0.021 1.793 0.407 0.1 7.967 — — —  Std. dev. 0.262 0.003 0.191 0.079 0.017 0.779 — — — 

N obs. 13 13 13 13 13 13 0 0 0 

6. Isolated Mean 1.698 0.188 0.068 0.51 0.255 1.156 — — —  Median 1.806 -0.02 -0.01 0.24 0.037 0.278 — — —  Minimum 1.132 -0.02 -0.01 0.099 0.015 0.221 — — —  Maximum 1.943 0.78 0.322 1.569 1.137 3.494 — — —  Std. dev. 0.323 0.335 0.142 0.617 0.493 1.426 — — — 

N obs. 5 5 5 5 5 5 0 0 0 

1995 Near-surface measurements: winter

1. Main channel Mean 2.528 0.011 1.966 0.069 0.037 5.729 — — —  Median 2.527 -0.02 1.914 0.073 0.043 6.21 — — —  Minimum 2.29 -0.02 1.665 0.042 0.014 4.171 — — —  Maximum 2.939 0.026 2.467 0.089 0.049 6.851 — — —  Std. dev. 0.168 0.005 0.193 0.016 0.013 1.135 — — — 

N obs. 12 12 12 12 12 12 0 0 0 

2. Side channel Mean 2.515 0.024 1.909 0.078 0.032 5.715 — — —  Median 2.54 -0.02 1.847 0.077 0.037 6.409 — — —  Minimum 2.296 -0.02 1.712 0.044 0.014 4.141 — — —  Maximum 2.92 0.105 2.244 0.121 0.05 7.105 — — —  Std. dev. 0.172 0.029 0.158 0.021 0.012 1.164 — — — 

N obs. 13 13 13 13 13 13 0 0 0 

3. Backwater Mean 2.414 0.019 1.753 0.075 0.034 5.865 — — —  Median 2.482 -0.02 1.864 0.085 0.038 6.325 — — —  Minimum 1.4 -0.02 0.379 0.044 -0.01 -0.05 — — —  Maximum 2.698 0.062 2.055 0.106 0.048 7.711 — — —  Std. dev. 0.276 0.016 0.359 0.019 0.013 1.737 — — — 

N obs. 19 18 18 19 19 19 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: winter

5. Impounded Mean 2.572 0.016 1.905 0.075 0.035 6.128 — — —  Median 2.553 -0.02 1.9 0.083 0.039 6.536 — — —  Minimum 2.405 -0.02 1.72 0.054 0.019 4.141 — — —  Maximum 2.812 0.042 2.12 0.095 0.047 7.359 — — —  Std. dev. 0.124 0.012 0.09 0.016 0.009 1.133 — — — 

N obs. 13 13 13 13 13 13 0 0 0 

1995 Near-surface measurements: spring

1. Main channel Mean 3.606 0.041 2.974 0.069 0.005 3.387 — — —  Median 3.681 0.03 2.952 0.07 -0.01 3.532 — — —  Minimum 2.954 -0.02 2.482 0.047 -0.01 2.691 — — —  Maximum 3.9 0.073 3.405 0.084 0.01 3.691 — — —  Std. dev. 0.264 0.024 0.275 0.011 0.001 0.363 — — — 

N obs. 13 13 13 13 13 8 0 0 0 

2. Side channel Mean 3.439 0.04 2.692 0.07 0.005 3.239 — — —  Median 3.52 0.03 2.677 0.069 -0.01 3.256 — — —  Minimum 2.949 -0.02 2.167 0.047 -0.01 2.336 — — —  Maximum 3.884 0.094 3.3 0.106 -0.01 4.019 — — —  Std. dev. 0.278 0.025 0.307 0.016 0 0.492 — — — 

N obs. 17 17 17 17 17 12 0 0 0 

3. Backwater Mean 2.799 0.048 1.852 0.074 0.005 2.513 — — —  Median 2.991 0.038 2.174 0.071 -0.01 2.915 — — —  Minimum 1.506 -0.02 -0.01 0.038 -0.01 0.133 — — —  Maximum 3.681 0.123 2.935 0.147 0.01 3.496 — — —  Std. dev. 0.647 0.026 0.898 0.026 88E-5 0.939 — — — 

N obs. 32 32 32 32 32 21 0 0 0 

5. Impounded Mean 3.305 0.048 2.616 0.061 0.005 3.471 — — —  Median 3.394 0.047 2.652 0.056 -0.01 3.365 — — —  Minimum 2.826 0.021 1.848 0.036 -0.01 3.016 — — —  Maximum 3.743 0.078 3.235 0.092 -0.01 3.96 — — —  Std. dev. 0.33 0.019 0.465 0.016 0 0.33 — — — 

N obs. 13 13 13 13 13 10 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: spring

6. Isolated Mean 1.631 0.33 0.021 0.136 0.016 -0.05 — — —  Median 1.475 0.232 -0.01 0.115 0.016 -0.05 — — —  Minimum 1.277 0.044 -0.01 0.092 0.01 -0.05 — — —  Maximum 2.097 0.693 0.067 0.206 0.021 -0.05 — — —  Std. dev. 0.364 0.275 0.026 0.04 0.004 — — — — 

N obs. 6 6 6 6 6 1 0 0 0 

1995 Near-surface measurements: summer

1. Main channel Mean 2.306 0.09 1.233 0.149 0.061 7.979 — — —  Median 2.371 0.073 1.345 0.156 0.063 7.979 — — —  Minimum 1.946 0.03 -0.01 0.099 0.043 7.979 — — —  Maximum 2.712 0.222 1.842 0.183 0.087 7.979 — — —  Std. dev. 0.254 0.061 0.471 0.025 0.012 — — — — 

N obs. 15 15 15 15 15 1 0 0 0 

2. Side channel Mean 2.306 0.05 1.278 0.154 0.07 7.421 — — —  Median 2.37 0.043 1.426 0.157 0.068 7.387 — — —  Minimum 1.71 -0.02 -0.01 0.091 0.058 6.927 — — —  Maximum 2.816 0.129 1.627 0.189 0.088 7.756 — — —  Std. dev. 0.332 0.029 0.418 0.025 0.009 0.325 — — — 

N obs. 15 15 15 15 15 5 0 0 0 

3. Backwater Mean 2.594 0.085 0.897 0.184 0.064 7.435 — — —  Median 2.379 0.055 0.865 0.162 0.067 7.597 — — —  Minimum 1.112 0.027 -0.01 0.125 0.014 6.22 — — —  Maximum 10.56 0.402 1.611 0.357 0.104 7.789 — — —  Std. dev. 1.583 0.075 0.541 0.055 0.017 0.47 — — — 

N obs. 32 32 32 32 32 10 0 0 0 

5. Impounded Mean 2.69 0.056 1.547 0.165 0.065 — — — —  Median 2.552 0.052 1.514 0.167 0.072 — — — —  Minimum 2.279 0.037 1.341 0.117 -0.01 — — — —  Maximum 4.421 0.092 1.91 0.203 0.094 — — — —  Std. dev. 0.509 0.016 0.159 0.025 0.023 — — — — 

N obs. 15 15 15 15 15 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: summer

6. Isolated Mean 2.886 0.637 0.313 1.271 0.686 4.214 — — —  Median 1.89 0.118 -0.01 0.545 0.01 2.788 — — —  Minimum 1.133 0.041 -0.01 0.063 -0.01 0.238 — — —  Maximum 5.781 2.322 0.969 4.17 3.19 11.91 — — —  Std. dev. 1.835 0.89 0.478 1.512 1.166 3.878 — — — 

N obs. 6 6 6 6 7 7 0 0 0 

1995 Near-surface measurements: fall

1. Main channel Mean 1.889 0.056 0.834 0.131 0.073 3.184 — — —  Median 1.776 0.058 0.716 0.119 0.076 1.951 — — —  Minimum 1.464 0.029 0.649 0.089 0.06 1.488 — — —  Maximum 2.469 0.079 1.242 0.182 0.085 6.112 — — —  Std. dev. 0.325 0.015 0.207 0.032 0.009 2.547 — — — 

N obs. 13 13 13 13 13 3 0 0 0 

2. Side channel Mean 1.894 0.061 0.861 0.137 0.07 5.365 — — —  Median 1.777 0.06 0.777 0.133 0.069 5.365 — — —  Minimum 1.416 0.031 0.595 0.09 0.048 5.365 — — —  Maximum 2.552 0.089 1.27 0.177 0.098 5.365 — — —  Std. dev. 0.39 0.015 0.266 0.026 0.014 — — — — 

N obs. 15 15 15 15 15 1 0 0 0 

3. Backwater Mean 1.52 0.072 0.463 0.144 0.051 2.327 — — —  Median 1.438 0.065 0.553 0.15 0.063 1.197 — — —  Minimum 0.905 -0.02 -0.01 0.026 -0.01 0.832 — — —  Maximum 2.28 0.356 0.883 0.334 0.098 5.252 — — —  Std. dev. 0.336 0.058 0.267 0.063 0.031 2.013 — — — 

N obs. 35 35 35 35 35 4 0 0 0 

5. Impounded Mean 1.588 0.062 0.658 0.161 0.07 — — — —  Median 1.586 0.061 0.66 0.149 0.072 — — — —  Minimum 1.384 0.022 0.58 0.108 0.052 — — — —  Maximum 1.906 0.102 0.757 0.302 0.09 — — — —  Std. dev. 0.124 0.024 0.046 0.049 0.012 — — — — 

N obs. 13 13 13 13 13 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

1995 Near-surface measurements: fall

6. Isolated Mean 1.533 0.159 0.06 0.644 0.481 — — — —  Median 1.387 0.04 -0.01 0.198 0.069 — — — —  Minimum 1.031 -0.02 -0.01 0.071 -0.01 — — — —  Maximum 2.442 0.427 0.274 1.61 1.36 — — — —  Std. dev. 0.484 0.168 0.107 0.736 0.666 — — — — 

N obs. 6 6 6 6 6 0 0 0 0 

1996 Near-surface measurements: winter

1. Main channel Mean 2.299 0.337 1.591 0.084 0.06 — — — —  Median 2.275 0.312 1.555 0.082 0.061 — — — —  Minimum 2.118 0.268 1.425 0.07 0.034 — — — —  Maximum 2.747 0.689 2.116 0.114 0.087 — — — —  Std. dev. 0.156 0.108 0.167 0.012 0.014 — — — — 

N obs. 13 13 13 13 13 0 0 0 0 

2. Side channel Mean 2.327 0.342 1.523 0.082 0.054 — — — —  Median 2.308 0.316 1.501 0.083 0.053 — — — —  Minimum 2.16 0.29 1.431 0.065 0.043 — — — —  Maximum 2.64 0.45 1.688 0.095 0.072 — — — —  Std. dev. 0.13 0.047 0.065 0.01 0.008 — — — — 

N obs. 16 16 16 16 16 0 0 0 0 

3. Backwater Mean 2.449 0.643 1.263 0.183 0.05 — — — —  Median 2.36 0.471 1.472 0.087 0.05 — — — —  Minimum 2.003 0.275 -0.01 0.067 -0.01 — — — —  Maximum 4.853 1.932 2.169 1.161 0.077 — — — —  Std. dev. 0.557 0.466 0.561 0.287 0.021 — — — — 

N obs. 24 24 24 24 24 0 0 0 0 

5. Impounded Mean 2.27 0.32 1.58 0.09 0.05 — — — —  Median 2.25 0.317 1.571 0.086 0.047 — — — —  Minimum 2.078 0.242 1.421 0.069 0.031 — — — —  Maximum 2.501 0.425 1.844 0.112 0.07 — — — —  Std. dev. 0.14 0.047 0.097 0.014 0.012 — — — — 

N obs. 13 13 13 13 13 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

1. Main channel Mean 1.45 — 0.676 0.107 0.042 — — — —  Median 1.396 — 0.734 0.1 0.042 — — — —  Minimum 1.136 — 0.297 0.09 0.023 — — — —  Maximum 1.628 — 0.852 0.13 0.05 — — — —  Std. dev. 0.142 — 0.162 0.014 0.007 — — — — 

N obs. 14 0 14 14 14 0 0 0 0 

2. Side channel Mean 1.446 — 0.628 0.104 0.04 — — — —  Median 1.478 — 0.566 0.103 0.041 — — — —  Minimum 0.999 — 0.347 0.082 0.029 — — — —  Maximum 1.7 — 1.322 0.126 0.045 — — — —  Std. dev. 0.176 — 0.224 0.011 0.004 — — — — 

N obs. 17 0 17 17 17 0 0 0 0 

3. Backwater Mean 1.456 — 0.598 0.088 0.039 — — — —  Median 1.341 — 0.531 0.084 0.039 — — — —  Minimum 0.832 — -0.01 0.051 0.025 — — — —  Maximum 3.013 — 2.303 0.119 0.044 — — — —  Std. dev. 0.452 — 0.487 0.017 0.004 — — — — 

N obs. 33 0 33 33 33 0 0 0 0 

5. Impounded Mean 1.459 — 0.515 0.102 0.041 — — — —  Median 1.365 — 0.477 0.103 0.041 — — — —  Minimum 1.205 — 0.352 0.086 0.029 — — — —  Maximum 2.017 — 0.852 0.114 0.047 — — — —  Std. dev. 0.266 — 0.143 0.009 0.005 — — — — 

N obs. 13 0 13 13 13 0 0 0 0 

6. Isolated Mean 1.538 — 0.121 — 0.037 — — — —  Median 1.248 — 0.087 — 0.037 — — — —  Minimum 0.97 — -0.01 — 0.031 — — — —  Maximum 3.476 — 0.41 — 0.04 — — — —  Std. dev. 0.873 — 0.149 — 0.003 — — — — 

N obs. 7 0 7 0 7 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

1. Main channel Mean 1.853 0.045 1.085 0.126 0.044 5.201 — — —  Median 1.801 0.038 1.118 0.106 0.041 5.274 — — —  Minimum 1.36 -0.02 0.729 0.082 0.012 4.462 — — —  Maximum 3.623 0.1 1.383 0.302 0.071 5.712 — — —  Std. dev. 0.564 0.028 0.223 0.068 0.018 0.491 — — — 

N obs. 13 13 13 9 13 6 0 0 0 

2. Side channel Mean 1.741 0.051 1.062 0.133 0.042 5.399 — — —  Median 1.713 0.048 1.112 0.113 0.038 5.665 — — —  Minimum 1.473 -0.02 0.826 0.09 0.014 4.373 — — —  Maximum 2.134 0.12 1.258 0.246 0.079 6.232 — — —  Std. dev. 0.176 0.031 0.125 0.045 0.021 0.754 — — — 

N obs. 17 17 17 10 17 7 0 0 0 

3. Backwater Mean 1.608 0.055 0.745 0.194 0.033 4.904 — — —  Median 1.68 0.05 0.87 0.122 0.025 5.348 — — —  Minimum 0.689 -0.02 -0.01 0.076 -0.01 2.015 — — —  Maximum 2.45 0.137 1.39 1.075 0.077 6.266 — — —  Std. dev. 0.39 0.026 0.487 0.232 0.023 1.273 — — — 

N obs. 32 32 32 29 32 25 0 0 0 

5. Impounded Mean 1.614 0.032 0.911 0.114 0.035 5.591 — — —  Median 1.586 0.026 0.881 0.118 0.03 5.552 — — —  Minimum 1.372 -0.02 0.617 0.098 0.016 5.552 — — —  Maximum 2.416 0.066 1.335 0.125 0.076 5.63 — — —  Std. dev. 0.268 0.017 0.171 0.011 0.018 0.056 — — — 

N obs. 14 14 14 5 14 2 0 0 0 

6. Isolated Mean 2.76 0.045 0.005 0.291 0.074 — — — —  Median 2.77 0.029 -0.01 0.254 -0.01 — — — —  Minimum 0.764 0.021 -0.01 0.041 -0.01 — — — —  Maximum 5.564 0.104 -0.01 0.459 0.323 — — — —  Std. dev. 1.83 0.034 0 0.175 0.14 — — — — 

N obs. 5 5 5 5 5 0 0 0 0 
F-37

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: fall

1. Main channel Mean 1.299 0.02 0.363 0.272 0.006 3.873 — — —  Median 1.285 -0.02 0.447 0.213 -0.01 3.873 — — —  Minimum 1.125 -0.02 -0.01 0.091 -0.01 3.873 — — —  Maximum 1.618 0.082 0.582 0.958 0.013 3.873 — — —  Std. dev. 0.126 0.022 0.163 0.224 0.002 — — — — 

N obs. 14 14 14 12 14 1 0 0 0 

2. Side channel Mean 1.259 0.014 0.238 0.248 0.005 — — — —  Median 1.26 -0.02 0.265 0.213 -0.01 — — — —  Minimum 0.972 -0.02 -0.01 0.117 -0.01 — — — —  Maximum 1.577 0.037 0.535 0.754 -0.01 — — — —  Std. dev. 0.151 0.008 0.176 0.157 0 — — — — 

N obs. 17 17 17 16 17 0 0 0 0 

3. Backwater Mean 1.123 0.015 0.155 0.292 0.005 — — — —  Median 1.159 -0.02 0.116 0.202 -0.01 — — — —  Minimum 0.562 -0.02 -0.01 0.037 -0.01 — — — —  Maximum 1.51 0.036 0.472 1.022 0.012 — — — —  Std. dev. 0.209 0.008 0.159 0.267 0.002 — — — — 

N obs. 35 35 35 23 35 0 0 0 0 

5. Impounded Mean 1.24 0.013 0.193 0.387 0.005 — — — —  Median 1.238 -0.02 0.191 0.212 -0.01 — — — —  Minimum 1.118 -0.02 -0.01 0.119 -0.01 — — — —  Maximum 1.355 0.029 0.497 1.184 -0.01 — — — —  Std. dev. 0.076 0.006 0.173 0.372 0 — — — — 

N obs. 14 14 14 13 14 0 0 0 0 

6. Isolated Mean 1.249 0.01 0.005 0.703 0.421 — — — —  Median 1.194 -0.02 -0.01 0.184 0.019 — — — —  Minimum 1.115 -0.02 -0.01 0.168 -0.01 — — — —  Maximum 1.448 -0.02 -0.01 2.249 1.778 — — — —  Std. dev. 0.131 0 0 1.031 0.769 — — — — 

N obs. 5 5 5 4 5 0 0 0 0 
F-38

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-39

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-40

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-41

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-42

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-43

 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-44

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-45

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-46

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-47

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-48

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-49

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-50

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

Onalaska Field Station. 

5. FUNDING NUMBERS

6. AUTHOR(S)

David M. Soballe,1

 James R. Fischer,2 Lisa A. Hodge-Richardson,2,3 and Troy L. Clemment2,4

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

Wisconsin Department of Natural Resources, 575 Lester Avenue, Onalaska, Wisconsin 54650.

3

Present address: Department of Natural Resources, 820 Industrial Drive, Suite 2, Sparta, Wisconsin 54656.

4

Present address: Department of Natural Resources, 910 Hwy 54 East, Black River Falls, Wisconsin 54615.

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-P003

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. Personnel from the LTRMP Onalaska (Wisconsin) Field Station made about 1,300 visits to

fixed limnological sampling sites and 2,100 visits to stratified random sites in the vicinity of Navigation Pool 8 from 1993 through 1996. An extended, late-season flood in

summer 1993 coincided with some of the highest nutrient and lowest dissolved oxygen (DO) concentrations recorded during the report period. Decreases in nutrient

concentrations (particularly nitrogen) and increases in water clarity occurred over the 4-year period. Midday DO concentrations were above 5 mg/L throughout most of the

year and across most of Pool 8, with localized exceptions during periods of snow cover. Pool 8 and its watershed are a net source of sediment to the Mississippi River; main

channel suspended solids concentrations were greater downstream than upstream, and concentrations in the tributaries were typically higher than in the main channel. Strong

seasonal patterns were evident for temperature, DO, Secchi transparency, turbidity, total and volatile suspended solids, silicate, chlorophyll a, and total phosphorus. Spatial

variability (among strata) of most measurements generally increased during lower discharge. Within the individual strata, the pattern of variability could be generalized as

follows: isolated backwater > contiguous backwater > impounded > side channel > main channel.

14. SUBJECT TERMS

Annual report, limnology, LTRMP, Mississippi River, water quality 

15. NUMBER OF PAGES

20 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.