Prepared for: 

Basin Electric 

Leland Olds Station, North Dakota 

Impingement Mortality and Entrainment 

Characterization Study (IMECS) 

Basin Electric – Leland Olds Station, 

ND 

ENSR Corporation 

September 2008 

Document No.: 10735-003 
Prepared for: 

Basin Electric 

Leland Olds Station, North Dakota 

Impingement Mortality and Entrainment 

Characterization Study (IMECS) 

Basin Electric – Leland Olds Station, 

ND 

_______________________________________ 

Prepared By: David Pillard, Ph.D. 

_______________________________________

Reviewed By: Jean Decker 

ENSR Corporation 

September 2008 

Document No.: 10735-003 
Report No. 10735-003-0200 i September 2008

Table of Contents 

Executive Summary ..........................................................................................................................................vi

Conformance with IM Performance Goals................................................................................................. vi

Implications for Technology Review and Compliance Strategy............................................................... vii

1.0 Introduction............................................................................................................................................... 1-1

1.1 Review of Facility and CDS ............................................................................................................ 1-1

1.2 Statement of IMECS Goals............................................................................................................. 1-1

1.2.1 Suspension of 316(b) Phase II Rule ................................................................................. 1-2

1.2.2 Strategy to Address the Rule’s Requirements.................................................................. 1-2

1.2.3 Support Issues Specific to Compliance Option ................................................................ 1-3

1.3 Document Organization .................................................................................................................. 1-3

2.0 Habitat Review.......................................................................................................................................... 2-1

2.1 Plant Location and CWIS Description ............................................................................................ 2-1

2.2 Habitat Summary............................................................................................................................. 2-2

3.0 Review of Historic and Sampling Study Data ...................................................................................... 3-1

3.1 Historical Biological and Physical Data .......................................................................................... 3-1

3.2 Literature Review............................................................................................................................. 3-2

3.3 Site-Specific Impingement Mortality Study..................................................................................... 3-2

3.3.1 Study Plan and Sampling Protocol ................................................................................... 3-2

3.3.2 Results of Sampling at LOS .............................................................................................. 3-2

3.3.3 Results of Sampling at Minnkota Power and Great River Energy................................... 3-4

3.4 Characterization of Susceptible Species........................................................................................ 3-4

3.4.1 Dominant and Incidental Species...................................................................................... 3-4

3.4.2 Handling Tolerance............................................................................................................ 3-6

3.4.3 Swimming Speeds............................................................................................................. 3-6

3.5 General Conclusions....................................................................................................................... 3-7

3.5.1 Life Stage and Taxonomy Data for all Species in the Garrison Reach are Well Understood.

............................................................................................................................................ 3-7

3.5.2 Life Stage and Taxonomy Data for all Species Collected in the Impingement Survey are 

Well Understood. ............................................................................................................... 3-7

3.5.3 The Species that are Most Commonly Impinged are Abundant in the Garrison Reach and 

Rare Species are Not Impinged........................................................................................ 3-8

3.5.4 Impingement Rates at LOS are Low and Impingement Mortality will have no Long-Lasting 

Consequences on the Populations of Impinged Species................................................. 3-8

3.6 Assessment of Data Sufficiency ..................................................................................................... 3-8
Report No. 10735-003-0200 ii September 2008

4.0 Data Interpretation ................................................................................................................................... 4-1

4.1 Overview.......................................................................................................................................... 4-1

4.1.1 Taxonomic Identifications.................................................................................................. 4-1

4.1.2 Characterization of Lifestages........................................................................................... 4-1

4.1.2.1 Size of Impinged Organisms.............................................................................. 4-1

4.1.2.2 Temporal Variations in IM .................................................................................. 4-1

4.1.2.3 Seasonal Variation ............................................................................................. 4-2

4.1.2.4 Diel Variation ...................................................................................................... 4-2

4.1.3 Correlation Analysis........................................................................................................... 4-3

4.1.4 Documentation of Current IM Rates ................................................................................. 4-3

4.2 Definition of Performance Basis ..................................................................................................... 4-5

4.2.1 Target Species................................................................................................................... 4-5

4.2.2 Calculation Baseline - Numbers vs. Biomass................................................................... 4-5

4.3 Conclusions ..................................................................................................................................... 4-6

4.3.1 Calculation Baseline - Abundance .................................................................................... 4-6

4.3.2 Calculation Baseline - Species Richness ......................................................................... 4-6

5.0 References ................................................................................................................................................ 5-1
Report No. 10735-003-0200 iii September 2008

List of Appendices 

Appendix A November 15, 2007 Letter from NDDH

Appendix B Literature Review Bibliography 

Appendix C Summary of Data Collected through June 2006 
Report No. 10735-003-0200 iv September 2008

List of Tables 

Table 1. Complete List of Fish Species Collected by North Dakota Game and Fish from 1997 to Summer 

 2006 at the Stanton Collection Site in the Garrison Reach 

Table 2. Species and Number of Fish Collected at LOS 

Table 3. Species and Number of Fish Collected at GRE 

Table 4. Comparison of Survival of Some Fish Species on Screens with Continuous Versus Intermittent 

Rotation (from EPRI 2003) 

Table 5. Large Fish Collected at LOS CWIS and Calculation of Hypothetical Burst Speed 

Table 6. Assessment of Data Sufficiency 

Table 7. Fish Collected by NDG&F in the Garrison Reach and Number Collected During One-Year IM 

Study at LOS 
Report No. 10735-003-0200 v September 2008

List of Figures 

Figure 1. Location of Leland-Olds Station Relative to Garrison Dam 

Figure 2. Close-Up View of LOS CWIS Location and CWISs of Nearby Power Plants 

Figure 3. Photographs of LOS CWIS 

Figure 4. Total Number of Fish Collected by ND Game and Fish 1997 to Summer 2006 

Figure 5. Totals on Each Sample Collection Date for the Three Most Abundant Fish Collected at Leland 

Olds 

Figure 6. Generalized Model of Burst Speed of Large Fish as it Relates to Total Length. From Wolter and 

Arlinghaus 2003 

Figure 7. Generalized Model of Burst Speed of Smaller Fish (≤ 50 mm) as it Relates to Total Length. 

1)Wolter and Arlinghaus Model, 2)Wardle (1975), 3)Wakeling et al. (1999) for carp, 4) Flore. Et 

al.(2001) for Nose Carp and Garner (1999) for 5) Roach and 6) Dace. 

Figure 8. Average Total Length of Adults and YOY Collected at the LOS CWIS 

Figure 9. Relationship Between Number of Fish Collected (all data) and Air Temperature 

Figure 10. Relationship Between Fish Biomass (All Data) and Plant Intake Volume 

Figure 11. Relationship Between Number of Fish Collected (Excluding High Biomass Events) and Plant 

Intake Volume 

Figure 12. Relationship Between Fish Biomass (Excluding High Biomass Events) and Plant Intake Volume 

Figure 13. Number of Fish Collected by NDG&F at Stanton Each Season 
Report No. 10735-003-0200 vi September 2008

Executive Summary 

This Impingement Mortality and Entrainment Characterization Study (IMECS) is a biological report that was 

part of the Comprehensive Demonstration Study (CDS) required by the previously promulgated Phase II of

Section 316(b) of the Clean Water Act. Even though significant sections of Phase II were remanded by a 

recent court decision, resulting in the suspension of the regulations for Phase II facilities, the ruling did not 

change preexisting requirements that permit authorities use best professional judgment to set conditions for 

cooling water intake structures. The North Dakota Department of Health (NDDH) still requires submittal of 

impingement characterization study data (see November 15, 2007 NDDH letter in Appendix A of this report). 

Information contained in this report is, therefore, still relevant and necessary. 

The IMECS required three primary items: 1) taxonomic identification of all fish and shellfish with potential to be 

impinged or entrained (if required); 2) a characterization of the life stages of these species; and 3) an estimate 

of the current impingement and/or entrainment rates at the plant. This report focuses on the impingement data 

at Basin Electric Power Cooperative’s (Basin Electric) Leland Olds Station (LOS), located near Stanton, North 

Dakota. 

Conformance with IM Performance Goals 

Basin Electric’s proposed approach to Phase II Rule compliance was to demonstrate that no additional control 

technology to reduce impingement mortality would be likely to be cost effective. The strength of the argument 

relative to the current system’s performance and cost effectiveness of additional controls lies with the 

demonstration in this IMECS, based on impingement data collected from June 2005 through June 2006 and 

the existing literature, that 

• the number of fish impinged is low relative to the total population densities in the Missouri River 

proximal to the intake structure; and 

• the species that are impinged are overwhelmingly small, forage (nongame) fish. 

The sampling plan was reviewed and approved by the U.S. Fish and Wildlife Service (USFWS) and North 

Dakota Game and Fish (NDG&F). Results and conclusions were clearly shown during the 12-month 

impingement mortality (IM) investigation, the design and results of which were critically reviewed by a wellknown North Dakota fisheries professional and were presented to North Dakota state officials, including North 

Dakota Game and Fish, as well as USFWS fisheries scientists. Specifically, the Impingement Mortality Study 

can be summarized as follows: 

• The study was conducted for a full year from mid-June 2005 through late June 2006. 

• Samples were collected every two weeks for 24 hours from the operating units of the LOS Cooling 

Water Intake Structure (CWIS). 

• During each sampling episode, a morning sample was collected and an evening sample were 

collected, both consisting of all fish impinged on the CWIS screens during the previous 12-hour period. 

• All debris was collected in a specially-constructed basket having the same screen size as the CWIS 

screens themselves; all debris was sorted and fish were removed. 

• All fish were identified and weight and length data were collected. 

• Any taxonomic questions were directed to a fisheries expert at NDG&F. 

• All data were consolidated and entered into a project database for analysis. 
Report No. 10735-003-0200 vii September 2008

• Additional physical and chemical data were collected concurrently with the fish. 

Analysis of the collected data demonstrated that: 

• Small species, such as emerald shiner, gizzard shad and rainbow smelt dominated the impinged 

population, with the latter being the most abundant throughout the collection period. 

• Overall, the assemblage of impinged fish was consistent, although density and diversity showed 

substantial seasonal variability, with the highest numbers being found in the late autumn and early 

winter. During the first three months of sample collection, rainbow smelt and emerald shiners were 

consistently the most common fish collected at the CWIS, although total numbers were low. In August 

2005, the emerald shiner disappeared from the collection basket and gizzard shad were first collected.

The greatest number of fish during a single collection episode was recovered on November 30, 2005; 

the vast majority of those fish (121 out of 127, or over 95%) were gizzard shad. Four more gizzard 

shad were collected in the evening sample on December 14, 2005, and then this specie was absent 

from the collection basket for the remainder of the study. The appearance of gizzard shad in the 

autumn of 2005 was also documented by North Dakota Game and Fish when they were conducting 

an electroshocking survey near their Stanton collection site in September 2005. The “run” of gizzard 

shad in autumn/early winter appears to be consistent with population trends observed for this species 

in other rivers 

• Sport fish collected from the CWIS included walleye (1 specimen), freshwater drum (3 specimens) and 

channel catfish (6 specimens). A total of sixteen species were collected during the 12-month study. 

• Typically only 2 to 3 species were collected during any single collection episode. On only one date 

were 4 species collected. 

• Mean (total) lengths of fish were low, ranging between 6 and 8 centimeters (cm) on nearly all dates. 

On occasion, the mean length was pushed higher by the collection of a very few large individuals. On 

February 22, 2006, for example, a single channel catfish measuring 42 cm long and 761 grams (g) 

was recovered; this was the largest fish collected during the study. 

• Mean weight was also low and relatively consistent, in most cases fluctuating between approximately 

1.5 and 4 g. As with length, higher mean weights were driven by the recovery of a few large fish. 

• The maximum size of rainbow smelt showed a general upward trend through February 2006, 

suggesting growth of the young-of-the-year cohort. However, minimum size did not generally change. 

Collection of all other species was too sporadic to identify size trends. 

• There were no strong correlations between any of the collected independent variables (e.g., water 

temperature) and either number of fish collected or biomass. 

• No state or federally listed species were collected. The LOS CWIS, therefore, is not likely to 

significantly impact any species of concern. 

Implications for Technology Review and Compliance Strategy 

In January 2007, the Second Circuit Court issued a decision on EPA’s Phase II Rule which significantly

impacted the current course of implementation of technologies for fish protection under 316(b). The court 

ruling invalidated much of the existing rule. Pursuant to that court ruling, EPA suspended requirements for 

CWISs at Phase II existing facilities until it has had the opportunity to address the Court’s remand. At this time, 

permit requirements for CWISs at Phase II facilities will be established on a case-by-case basis by the 

permitting agency using best professional judgment (BPJ). 
Report No. 10735-003-0200 viii September 2008

The Garrison Reach of the Missouri River is a unique location – historically, it was a wide, meandering channel 

with abundant habitat for warm water fishes. However, after the construction of the Garrison Dam and Lake 

Sakakawea in 1953, flow in the river became highly regulated and water temperature decreased significantly 

due to bottom release of water from the reservoir. In addition, sediment loading dropped significantly with a 

corresponding increase in water clarity. Seasonal effects (such as icing and debris loading), navigational 

effects and water velocities are all significant factors in the technology review. Although some technologies 

have been proven to reduce IM, few technologies are potentially effective for intakes located on the main 

channel of the Missouri River, where extreme cold, ice buildup and large debris loads may severely limit the 

application and effectiveness of some IM-reduction strategies. 
Report No. 10785-004-0600 1-1 September 2008

1.0 Introduction 

1.1 Review of Facility and CDS 

The purpose of this Impingement Mortality and Entrainment Characterization Study (IMECS) was to evaluate 

fish and shellfish species that were impinged at the Basin Electric Power Cooperative (Basin Electric) Leland 

Olds Station (LOS) near Stanton, North Dakota. The plant is located at approximately river mile 1371, on the 

southwest bank of the Missouri River, approximately 10 miles east of Stanton, ND. Under the original Phases 

II rule, the cooling water intake structure (s) (CWIS) were not subject to the entrainment performance

standards since they withdrew less than 5% of the mean daily flow of the Missouri River at this location. Five 

percent was the regulatory applicability threshold for entrainment reduction. 

The Leland Olds 1 & 2 CWISs withdraw water directly from the Missouri River through two short concrete

forebays per unit that are flush with the river bank. The moderate water velocities withdrawn by LOS and 

sparse fish populations of the river minimize the fish that enter the plant’s cooling water system. Much of this 

IMECS focuses on the results of the year-long impingement mortality (IM) study that was conducted at LOS 

and at two other power plants in the immediate vicinity. 

In the Proposal for Information Collection (PIC), Basin Electric proposed to pursue Compliance Option 5 and 

demonstrate to the Director that the cost of installation of any of the available technologies would be 

significantly higher than any benefit that might result to the local fishery. EPA’s recent suspension of the 

Phase II rule following the ruling by the Second Circuit Court of Appeals has halted, for the time being, the use 

of a cost-benefit analysis for compliance purposes (see Section 1.2.1). Given this development, there is no 

basis at this time to pursue Compliance Option 5 or any compliance option that has been remanded and may 

be omitted from revised regulations. Despite the recent court decision regarding several aspects of EPA’s 

proposed compliance approach, the biological assessment in this IMECS is necessary to evaluate the 

potential effectiveness of new technologies at the CWIS and to assist in evaluating actual impacts to local fish 

populations. 

The Rule allowed the use of historical data and data from “like” facilities to meet the objectives of the rule if the 

data are representative of the current operation of the facility, and of the current biological conditions in the 

source waterbody. In addition to impingement data collected at the LOS Station, impingement data was also 

collected at two other open-cycle power generation plants located on the Garrison Reach of the Missouri 

River. These data are discussed in this report as the data are relevant to the selected compliance approach. 

The data set reviewed within this IMECS also includes data from the North Dakota Game and Fish 

Department (NDG&F) who have sampled ambient fish populations in a nearby location for a number of years. 

Through literature and data review, Basin Electric has concluded that there have been no significant changes 

in the Garrison Reach fisheries (density or diversity) in recent years and there are no anticipated changes for 

the foreseeable future. Therefore, Basin Electric believes the historic and collected impingement data are 

representative of current, and future, conditions. 

1.2 Statement of IMECS Goals 

The original requirements for the IMECS were found in Part 125 of the Clean Water Act, Rules 40 CFR 

Section 125.95(b)(3)(i), (ii), and (iii). To provide context for this study, the following is the excerpted portion of 

the rule (§125.95(b)(3)): 

Impingement Mortality and/or Entrainment Characterization Study. You must submit to the Director an 

Impingement Mortality and/or Entrainment Characterization Study whose purpose is to provide information to support the 

development of a calculation baseline for evaluating impingement mortality and entrainment and to characterize current 
Report No. 10785-004-0600 1-2 September 2008

impingement mortality and entrainment. The Impingement Mortality and/or Entrainment Characterization Study must 

include the following, in sufficient detail to support development of the other elements of the Comprehensive Demonstration 

Study: 

(i) Taxonomic identifications of all life stages of fish, shellfish, and any species protected under Federal, State, or 

Tribal Law (including threatened or endangered species) that are in the vicinity of the cooling water intake 

structure(s) and are susceptible to impingement and entrainment; 

(ii) A characterization of all life stages of fish, shellfish, and any species protected under Federal, State, or Tribal 

Law (including threatened or endangered species) identified pursuant to paragraph (b)(3)(i) of this section, 

including a description of the abundance and temporal and spatial characteristics in the vicinity of the cooling 

water intake structure(s), based on sufficient data to characterize annual, seasonal, and diel variations in 

impingement mortality and entrainment (e.g., related to climate and weather differences, spawning, feeding and 

water column migration). These may include historical data that are representative of the current operation of 

your facility and of biological conditions at the site; 

(iii) Documentation of the current impingement mortality and entrainment of all life stages of fish, shellfish, and any 

species protected under Federal, State, or Tribal Law (including threatened or endangered species) identified 

pursuant to paragraph (b)(3)(i) of this section and an estimate of impingement mortality and entrainment to be 

used as the calculation baseline. The documentation may include historical data that are representative of the 

current operation of your facility and of biological conditions at the site. Impingement mortality and entrainment 

samples to support the calculations required in paragraphs (b)(4)(i)(C) and (b)(5)(iii) of this section must be 

collected during periods of representative operational flows for the cooling water intake structure and the flows 

associated with the samples must be documented.

1.2.1 Suspension of 316(b) Phase II Rule 

On January 25, 2007, the U.S. Second Circuit Court issued a decision on EPA’s Phase II Rule (Riverkeeper 

vs. EPA). That decision invalidated several sections of the existing CWIS rules, while leaving others in place, 

including compliance deadlines. On July 9, 2007, the EPA suspended the Phase II requirements pending 

review, consideration and resolution of the issues raised by the Court’s remand (Federal Register, Vol. 72, 

Number 130, July 9, 2007). The one compliance alternative that was not suspended was the use of a closedcycle recirculating system, rather than a once-through cooling system. 

Although the Phase II compliance alternatives (except for a recirculating system) have been suspended for 

now, the January 8, 2008 deadline for submitting Comprehensive Demonstration Study (CDS) reports remains 

in effect, unless the state permitting agency relieves the plant of this requirement. The North Dakota

Department of Health (NDDH) has relieved Basin Electric (and the other Missouri River facilities) from

submitting CDS reports. Further, NDDH, in a November 15, 2007 letter to Basin, proposed a modification of 

the existing NPDES permit to move the IMECS report submission date to January 7, 2009 (see Appendix A). 

NPDES permit requirements for cooling water intake structures at Phase II facilities will be established by 

NDDH on a case-by-case basis using Best Professional Judgment (BPJ). 

1.2.2 Strategy to Address the Rule’s Requirements 

Basin Electric believes the three primary requirements of the original Phases II rule have been met by using 

the historical and impingement mortality study datasets. Taxonomic identification and life stages of species 

with potential for impingement are well understood. Additionally, the impingement rates established in this 

IMECS were calculated using data collected year-round to account for potential diel and seasonal effects. 
Report No. 10785-004-0600 1-3 September 2008

1.2.3 Support Issues Specific to Compliance Option 

The Second Circuit Court rulings puts into significant doubt the likelihood that several previously available 

options will be acceptable for compliance to any future Phase II, or equivalent, Rule. However, Basin Electric 

believes that the information presented in this document will support the conclusion that the actual costs of 

compliance are “significantly greater” than the benefits to be gained by the local fishery. Based on this 

conclusion, Basin Electric believes that available technologies and operational measures are either infeasible 

or significantly more costly than the benefits to be gained. 

1.3 Document Organization 

The remainder of this document is organized as follows: 

Section 2 is a presentation of the habitat types in the Garrison Reach of the Missouri River and the location of 

the LOS intake structures relative to habitat types. 

Section 3 is an overview of the available information reviewed for this report. A bibliography of the reviewed

literature is provided in Appendix B. 

Section 4 provides the major findings of the data assessment. This section is organized in accordance with 

the primary requirements of Rule 125.95(b) focusing on taxonomic identification, life-stage characterization, 

and current impingement mortality rates. 

Section 5 is the list of references used for the IMECS analysis. 

Tables, Figures, and Appendices referenced in this document are provided at the end of the document. 
Report No. 10735-003-0200 2-1 September 2008

2.0 Habitat Review 

Historically, the Missouri River was a wide, meandering system, with abundant shallow channel borders, side 

channels, and back waters. Shifting sand bars and abundant debris provided ample habitat for numerous 

warm-water fishes and invertebrates, but also made navigation difficult or impossible in some areas. 

Channelization, particularly in the lower Missouri, has allowed commercial navigation but has eliminated many 

of the shifting sandbars and continuity with side channels and backwaters. In the upper Missouri, reservoir 

construction has created a series of deep-water habitats connected by inter-reservoir reaches that are

significantly different in structure and ecology than the pre-impoundment system. The Garrison Dam was

closed in April of 1953, forming Lake Sakakawea, which is the largest of the Missouri River mainstem 

reservoirs. At maximum surface elevation of 1855 feet (above mean sea level), Lake Sakakawea has a 

storage capacity of approximately 24.7 million acre feet and covers 385,615 (surface) acres. 

The LOS intakes are located on the Garrison Reach of the Missouri River, approximately 20 miles downstream 

of the Garrison Dam. The location of the Leland Olds station relative to the Garrison Dam is presented in 

Figure 1. A close-up view of the LOS CWIS location and the CWISs of other nearby power plants are 

provided in Figure 2. Flow in this stretch of the river is totally regulated and will vary according to release rates 

from the reservoir. The closure of Garrison Dam, the fifth largest earthen dam in the United States, triggered a 

shift in the nature of the Missouri River downstream of the dam. The average annual summer surface 

temperature in Lake Sakakawea is 19oC (66oF), which is colder than all other Missouri River mainstem 

reservoirs. The original dam intake is located approximately 160 feet below the lake’s surface (at full pool). In 

July 2005 the Corps of Engineers completed a temporary retrofit on the dam intake structure to allow water to 

be taken from higher in the water column, thus potentially increasing the temperature of the discharge water. 

Despite this recent change, however, the water entering the Garrison Reach of the Missouri River is still much 

colder than historic conditions, and remains cold even during the hottest summer months. Maximum water

temperatures in the channel usually do not exceed 20oC (68oF) at Bismarck (70 miles downstream of Garrison 

Dam). 

The formation of Lake Sakakawea also resulted in a change in the sediment transport of the Missouri River. 

Historically a very silt-laden system, much of the bed load of fine material is now deposited in the upper 

reaches of Lake Sakakawea. Since the dam’s closure, approximately 37 percent of the reservoir’s gross 

storage capacity has been lost to sedimentation. The sediment load of the Missouri River below Garrison Dam 

has decreased dramatically, improving water clarity, but adversely affecting habitat for some fish species. 

The main tributaries of the Garrison Reach of the Missouri River are the Knife and Heart Rivers and Painted 

Woods and Square Butte Creek. The Knife River joins the Missouri River from the west, only a short distance 

upstream of the Leland Olds station. Local run-off into the Missouri River is sparse and seasonal so that the 

vast majority of flow through the Garrison Reach is due to release from the dam. Flow in the Garrison Reach 

has averaged 22,490 cfs from 1927 through 2001, as measured at the Bismarck USGS gauging station. Since 

construction of the dam, annual average flow has remained somewhat near this historical mean, though 

average monthly flows can vary widely due to release rates from the dam which vary depending on hydropower considerations and/or specific hydraulic and release requirements of Lakes Sakakawea and Oahe. 

2.1 Plant Location and CWIS Description 

The Leland Olds Station, located at approximately river mile 1371, operates two generating units that draw 

cooling water directly from the Missouri River. Unit #1, which began operation in 1966, is rated for 216 MW 

and has the capacity to draw 105 MGD from the river for cooling water and other purposes. Unit #2, which was 

built in the early 1970s and began commercial operation in 1975, is rated at 440 MW with a design intake 

capacity of 225 MGD. Photos of the CWIS structures are presented as Figure 3. 
Report No. 10735-003-0200 2-2 September 2008

Each of the units that comprise the CWIS includes two short concrete forebays (total of four forebays) that are 

flush with the river bank. In the winter, a spray header situated at the front of the forebays, is used to 

recirculate some of the warm water that has passed through the plant to raise the temperature of the incoming 

water and prevent ice formation. Also, during winter operation, the warm water discharge is moved to a

location upstream of the intake structures to help minimize ice build-up. 

Water is drawn into the forebays and through trash racks that exclude large objects (Figure 3b), by four cooling 

water pumps, two per unit and one for each forebay. The trash racks are mechanically cleared of excessive 

debris when necessary. Prior to entering the pump wet well, the water passes through traveling screens that 

capture and retain smaller bits of debris and fish (Figure 3c). The 3/8-inch mesh traveling screens are cleaned 

with 125 psi wash sprays when the operator determines, through visual inspection, that build-up is occurring. 

The screens also are equipped with pressure drop instrumentation, whereby the wash sprays are 

automatically activated when the pressure drop across the screens exceeds a setpoint. Wash water, and the 

debris it removes, is collected in a sluiceway that returns the collected material directly to the river. 

This segment of the Missouri River, including Lake Sakakawea and Lake Oahe, is considered a Class I stream 

under North Dakota water quality standards and is fully supported for primary contact recreation, secondary 

contact recreation, fish and wildlife propagation and drinking water supply. 

2.2 Habitat Summary 

The dominant habitat surrounding the intake structure (based on conditions as determined during mean flow) 

can be characterized as mainstem river channel. A certain amount of bank stabilization has been instituted on 

the south/southwest river banks in order to prevent unacceptable lateral erosion. The north/northeast river 

bank, however, is generally not stabilized and includes some shallow water habitat which may be more subject 

to exposure and drying during low flows, in a manner reminiscent of historical Missouri River hydrology. Near 

the intake structures, main channel characteristics include moderate river flows, relatively cool water 

temperatures, low to moderate turbidities, low to moderate suspended and dissolved solids (except during 

spring run-off), and mobile bed materials. Larger rocks and cobble are more likely to occur in the channel 

where flows are the highest. Shifting sandbars are present, depending on water flow, in the channel border 

areas towards the north bank. 

Agriculture is the predominant land use along the Missouri River near LOS and much of the Garrison Reach. 

Near-river riparian habitat, however, includes vegetated buffer zones of woodland and grasses where many 

species are found. Several species of birds can be found along the Missouri River, including plovers, pipers, 

ducks, geese and raptors. Mammals may be less visible than birds, but nevertheless several species are 

common including whitetail deer, raccoon, fox and various weasel species. Most of these species depend on 

the Missouri River and the riparian landscape for water, food and shelter. 
Report No. 10735-003-0200 3-1 September 2008

3.0 Review of Historic and Sampling Study Data 

3.1 Historical Biological and Physical Data 

The LOS CWIS is located on the Garrison Reach of the Missouri River. This reach has been studied 

thoroughly with regard to aquatic species for many years by Federal and State agencies as well as other 

independent researchers. Twenty reports on various aspects of the status of the fishery along the Garrison 

Reach have been researched during the development of this IMECS (a bibliography of these sources is 

provided in Appendix A). Most significantly, NDG&F has conducted fish population studies in the Garrison 

Reach since 1991. These studies involved biannual fish collection at seven locations in the Garrison Reach. 

One of these collection locations is offshore of the Great River Energy (GRE) Stanton Station cooling water 

outfall, which is located just downstream of the Stanton CWIS and upstream of the LOS CWIS, and which is in 

a similar river regime as the Milton R. Young Station river CWIS, 4 miles downstream. The location of the 

NDGF Stanton sampling point is identified on Figure 1. 

Table 1 presents a complete list of all the fish species identified in the Garrison Reach from 1991 through the 

summer of 20061. The most common fish collected by NDG&F at the Stanton Station from 1997 through the 

summer of 2006 was the white sucker, followed by the river carpsucker (Figure 4). Using electrofishing 

methods along a transect, NDG&F collected more species than were impinged at the LOS CWIS. The 

proportion of certain species was also different in the NDG&F collections, and the fish collected by NDG&F 

were larger than those impinged at the LOS CWIS. There was not a well-defined trend with regard to which 

species were more prevalent in the summer versus fall. Bigmouth buffalo, common carp, emerald shiner and 

others have been more abundant in the fall collections, while species such as river carpsucker and walleye 

were more frequently collected in the summer. 

The data collected by NDF&G, as well as by other researchers, provide a relevant and ongoing 

characterization of the biological conditions and populations in the river near the intake structure of the LOS 

power plant. The data are representative of current conditions and were collected using appropriate QA/QC 

procedures by agencies of the State of North Dakota. The Impingement Characterization Study as described 

in this PIC will comply with the third condition listed in Section 1.2 and will complete the data set required by 

the rule. 

In 1974 and 1978, studies were conducted by Dr. Joe Neel with the University of North Dakota at the request 

of Basin Electric. The studies were intended to determine the temperature, chemical and biological effects of 

the water withdrawal and discharge from the station. The 1978 study, “Life in the Missouri River with Warming 

by 676 Megawatts Gross Steam Generated Power Production”, included fish sampling at the intakes, at the 

screens and wash water return and downstream of the discharge. Observations and sampling were mainly 

conducted in the late spring and summer months. Fifteen species of fish were observed or captured and the 

text of the report states that primarily bullhead fingerlings were found in the intakes and on the intake screens. 

The data presented in the report indicated that during fifteen days of sampling the traveling screens, 56 fish 

were recovered from intake screen washings and 44 of these fish were black bullheads. River temperatures 

were slightly elevated in the vicinity of the discharge but the report states that they were not as high as 

temperatures found naturally in other stretches of the river. The report states that “the intake does not appear 

to pose a great threat to adult fish, but is more hazardous to young, particularly to schooling bullheads.” 

 

1

 North Dakota Fisheries Investigations, Aquatic Investigations of the Missouri Mainstream in North Dakota, by Jeff 

Hendrickson, North Dakota Game and Fish Department, March 2004, and 2005/2006 summaries provided by Jeff 

Hendrickson. 
Report No. 10735-003-0200 3-2 September 2008

A review of a recent publication, “Distribution and habitat use of sturgeon chubs (Macrhybopsis gelida) and 

sicklefin chubs (M. meeki) in the Missouri and Yellowstone Rivers, North Dakota” (Everett et al. 2004) 

indicated that in recent sampling studies of the Missouri River in the vicinity of the station, there were no chubs 

of either species collected. The authors of the study concluded that this was probably due to significantly 

deeper, faster and clearer water than was found in the other river segments studied. 

The existing data have been compared to the results of the impingement mortality study and the datasets are 

consistent in represented species and specimen size when considering the differences in collection methods. 

The datasets have also been evaluated by Dr. Steven Kelsch, a professor at the University of North Dakota 

and a recognized expert in North Dakota fisheries, and he concurs that the recently collected data are

consistent with other data from the Garrison Reach and known information on population densities and 

behaviors. 

3.2 Literature Review 

Twenty reports on various aspects of the status of the fishery along the Garrison Reach have been researched 

during the development of this IMECS. A bibliography of these sources is provided in Appendix C. As stated 

in the previous section, quantitative data and anecdotal information concerning the status of the fishery since 

the closure of the Garrison Dam are consistent with the results of the impingement mortality study, given 

differences in collection methodologies. 

3.3 Site-Specific Impingement Mortality Study 

3.3.1 Study Plan and Sampling Protocol 

The study plan and sampling protocol for conducting the site-specific impingement mortality study was 

developed by Basin Electric and ENSR and reviewed by the North Dakota Department of Health and Dr. 

Steven Kelsch. The plan and protocol were also presented to USFWS and NDG&F for their review and input. 

Appropriate comments and suggestions were incorporated and station-specific procedures were finalized.

Following preparation and applicable training (including health and safety planning), the field study was 

initiated in mid-June 2005. 

3.3.2 Results of Sampling at LOS 

Appendix C provides the full report for the year-long impingement mortality study conducted at LOS and two 

other nearby power plants, Minnkota Power’s Milton R. Young Station and Great River Energy’s (GRE’s) 

Stanton Station. The methodology of the study can be summarized as follows: 

• Samples were collected at two-week intervals unless interrupted by weather from June 15, 2005 

through June 28, 2006. All fish impinged over a 24 hour period were collected at 12 hour 

intervals. 

• The evening before the collection day, screens were rotated, washed and then left in place until 

the following morning. At that time, the screens were washed and all debris, including fish, was 

caught in a collection basket. The screens were again left in place and the same activities were 

repeated in the evening. 

• Debris in the collection basket was sorted and all fish were removed. The fish were placed in a 

bag or cooler for later measurement. 

• Additional data were collected at each facility, including water and air temperature, water velocity 

in the forebays (using a General Oceanics Flow Meter) and plant output (in megawatts). 
Report No. 10735-003-0200 3-3 September 2008

• Weight of the fish was recorded to the nearest 0.5 g and total and standard length of each fish 

was measured. It was also noted whether the fish were alive or dead when they were removed 

from the basket. 

• Operating data and fish data were maintained in a database - all raw data were also maintained. 

• A voucher collection was made; representative specimens of most species are included. 

• To evaluate any relationship between conditions at the facility/CWIS and the number of fish 

collected, stepwise regression analysis was conducted using Statistix (Analytical Software 

2003). 

The results of the impingement mortality study for LOS can be summarized as follows: 

• Sixteen species were collected; the total number of fish collected was 397 (Table 2). Total 

biomass collected was 5,418.7 grams or an average of 13.6 grams per fish. 

• Throughout the entire collection period, morning samples tended to yield more fish than the 

evening samples, although there were exceptions. 

• Over the collection period, substantial species shifts were seen. From June 2005 through 

February 2006, the rainbow smelt was, with a couple exceptions, the most common species 

collected. From June through August 2005 the emerald shiner was the second most common 

species collected. 

• Gizzard shad appeared in August 2005 and were the most abundant fish collected for five 

collection episodes (24-h period). On November 20, 2005, over 95% of the fish collected were 

gizzard shad. This species disappeared from the collection basket after December 14, 2005. 

• The total number of fish was low in February and early March, but in late March, emerald 

shiners emerged as the dominant species in the collection basket and remained the most 

common fish for the rest of the study period, on some dates being the only species collected. 

• Weight and length of the three most common species (rainbow smelt, emerald shiner and 

gizzard shad) was relatively consistent over the entire study period. Mean fish size (weight and 

length) did appear to rise slightly in late 2005 and early 2006, but too few fish were collected to 

suggest a shift in the size of fish being sampled. Weights and lengths decreased again in spring 

2006. Small fish have the greatest potential for impingement. 

• Total fish biomass showed considerable temporal variability and was often influenced by large 

specimens; total biomass was consistently low after February 2006. 

• There were no strong correlations between any of the collected independent variables and either 

number of fish or biomass. The best single-variable correlations for number of fish or biomass 

(when all of the fish collection data were included) were with air temperature (for number of fish, 

r

2 = 0.14) and plant intake water volume (for biomass, r2

 = 0.12). 

• When the collection events with high biomass were excluded form the dataset, plant intake 

volume explained the most data variation for number of fish and biomass (r2 = 0.21 for both 

metrics). 

• Using stepwise regression to analyze the full datasets, only air temperature and plant intake 

volume were retained as significant independent variables for number of fish and biomass, 
Report No. 10735-003-0200 3-4 September 2008

respectively. Excluding high-biomass events, water temperature and flow (GPM) were retained 

as significant independent variables explaining fish biomass (r2 = 0.31). 

• No specimens of threatened or endangered species were collected. 

• The species collected were not of special concern, as defined by the USFWS or NDG&F. Of the 

three most commonly impinged species, rainbow smelt was introduced into the Upper Missouri 

River system as forage food for introduced salmonid game species and gizzard shad is a 

peripheral species in this section of the Missouri River, probably near the northern limits of its 

range, which does not extend into Lake Sakakawea. 

3.3.3 Results of Sampling at Minnkota Power and Great River Energy 

As previously explained, the year long impingement mortality study included biweekly sampling at two other 

nearly stations, Minnkota Power’s Milton R. Young Station (MRY) and Great River Energy’s (GRE’s) Stanton 

Station. Their results are summarized in the following sections. 

Milton R. Young Station

From June 2005 through August 2005, no impinged fish were found at the MRY river intakes and screens. 

With approval from the North Dakota Department of Health (NDDH), collection frequency was reduced – it was 

agreed that if the number of fish impinged increased significantly at the other two stations during a collection 

event, that a sample would be scheduled at MRY. There was one such event in April 2006 but no fish were 

found at the MRY screens. 

No impinged fish were found on the MRY screens during the entire year of collection events. 

GRE, Stanton Station

Fourteen species, totaling 474 fish, were collected. Total biomass collected was 2,815 grams or an average of 

5.9 grams per fish. Table 3 provides the species list and the total count for each species. 

Species and number of fish collected were very similar to the results at LOS – collection days that experienced 

larger numbers of fish occurred at both stations. Again, there were no strong correlations between any of the 

collected independent variables and either number of fish or biomass. More detailed data for GRE can be 

found in Appendix C. 

3.4 Characterization of Susceptible Species 

The following is a brief summary of the dominant species impinged at LOS over the year long impingement 

mortality study. Handling tolerances and swimming speeds are also discussed. 

3.4.1 Dominant and Incidental Species 

The three dominant species that were impinged (90% of individuals collected) were rainbow smelt, gizzard 

shad and emerald shiner. General information on these species is presented below. 

Rainbow Smelt

Rainbow smelt (Osmerus mordax) were introduced into Lake Sakakawea in the early 1970s to provide a prey 

species for larger game species, including Chinook salmon, that were released into the lake in 1976. Smelt are 

small, slivery fish that can reach lengths of 4 to 8 inches as adults. This species prefers cooler water, and has 

been found in deep waters of various freshwater lakes. In the spring, smelt migrate up smaller tributaries to 
Report No. 10735-003-0200 3-5 September 2008

spawn over sandbars having moderate currents that maintain adequate oxygen levels (Pflieger 1997). 

Rainbow smelt that have passed out of Lake Sakakawea likely maintain populations in the Garrison Reach of 

the Missouri River, thanks to the colder water being released from the lake. Water levels and associated 

temperatures in Sakakawea probably influence smelt population densities. From 2001 to 2002, for example, 

smelt populations decreased in the lake from an estimated 831,000 kg to 103,000 kg, respectively, as a

response to warming temperatures (Lee 2003). 

Gizzard Shad

Gizzard shad (Dorosoma cepedianum) occur primarily in freshwater and are most abundant in large rivers and 

reservoirs, avoiding high gradient streams. They are relatively abundant in the lower Missouri River and are 

found in Lake Oahe, but their range probably does not extend into Lake Sakakawea (Galat et al. 2005). The 

species is most often found in large schools. Spawning generally takes place in late spring, usually in shallow 

protected water. Shad are prolific fish, with females laying in excess of 350,000 eggs annually, on average 

(Bodola 1966). Hatch occurs anywhere from 36 hours to one week after spawning, depending on temperature 

(Bodola 1966). Gizzard shad are planktivorous. The young feed on microscopic animals and plants, as well as 

small insect larvae, while adults feed by filtering small food items from the water using their long gill rakers. 

Gizzard shad generally grow to 14 inches and provide forage for most game species (Miller 1960), although 

rapid growth limits duration of susceptibility to predators (Bodola 1966). Ross (2001) also noted that young 

gizzard shad tend to occur along shorelines in very shallow water, gradually moving offshore into deep water 

as they grow. Individuals older than age class 3 rarely occur in shallow water (Bodola 1966). Gizzard shad 

have little commercial or recreational importance although they likely serve as forage for game fish. 

Emerald Shiner

Emerald shiner (Notropis atherinoides) is a small fish, reaching only about 2 to 3.5 inches in length as an adult. 

It has an overall silvery appearance, with an iridescent, light green dorsal surface. One of about 100 species 

within the genus Notropis in the Missouri River system, it is common throughout the upper Missouri. A native 

of the Missouri and Yellowstone Rivers, the emerald shiner is tolerant of a wide range of turbidities, bottom 

types and current velocities (Pflieger 1997). This species is characteristic of large, open channels in medium to 

large rivers with sandy substrates (Cross and Collins 1995), making the Garrison Reach and ideal location for 

this common fish. The emerald shiner generally spawns between July and August (Scott and Crossman 1973). 

Ideal temperature is 25oC (Campbell and MacCrimmon 1970), and therefore water temperature may affect the 

spawning period, making it earlier or latter in the year. Females lay between 870 and 8700 eggs (Campbell 

and MacCrimmon 1970) which hatch within 24 hours (Scott and Crossman 1973). Fish stay near shore until 

fall and then move into deep waters to overwinter. They feed on midge larvae, zooplankton, benthic 

microinvertebrates and algae (Campbell and MacCrimmon 1970). 

The occurrence of rainbow smelt, gizzard shad and emerald shiner in the collection basket at LOS is illustrated 

in Figure 5. 

The remaining individuals collected consisted of sport fish and a few incidental species: 

Sport Fish

Walleye is one of the predominant sport fish in the Upper Missouri River. Other species include perch,

northern pike, catfish, smallmouth bass, sauger and sunfish. Introduced salmonid species (e.g., rainbow trout) 

may also be found although warm-water species are the dominant sport fish in the Missouri River downstream 

of Garrison Dam. Only a few individual sport fish were collected during the impingement investigation at LOS, 

including walleye and channel catfish; seven sport fish or 1.8% of the total were collected. 
Report No. 10735-003-0200 3-6 September 2008

Threatened or Endangered Species

Although the Garrison Reach is potential habitat for several threatened and endangered species such as the 

pallid sturgeon, no threatened or endangered species were collected in the impingement mortality study. 

3.4.2 Handling Tolerance 

Table 4 presents data summarized by EPRI (2003) on the observed impingement survival of different fish

species. This review does not include all species but does summarize an extensive set of studies for many 

important species. To support the assessment of potential survival upon fish handling and return, the species 

that are common in the river and commonly impinged were assessed relative to the average and median rate 

of survival following removal from traveling screens. 

EPRI (2003) indicated that the median extended survival for gizzard shad was 11% for intermittently rotated 

screens and 9% for continuously rotated screens. The other two dominant species are not represented in this 

table but other similar species such as freshwater drum show limited extended survival (20%). This suggests 

that any sort of fish handling and return system is not likely to achieve significant reductions in impingement 

mortality for the three finfish species that dominate impingement at LOS. These trends will be evaluated 

further relative to potential mitigation measures in subsequent portions of the CDS. 

3.4.3 Swimming Speeds 

In the Preamble to the Rule, the US EPA states “intake velocity is one of the key factors that can affect the 

impingement of fish and other aquatic biota”. In the immediate area of the intake structure, the velocity of 

water entering a CWIS exerts a direct physical force against which fish and other organisms must act to avoid 

impingement and entrainment. In addition, technologies (wedgewire screens and velocity caps) may reduce 

or change CWIS velocities, and hence impingement. 

Native fishes of the upper Missouri River are generally adapted to environments with relatively slow current 

velocities (Bowen et al. 2003). Areas of high velocity are present, however, and seasonal rainfall and snow 

melt can result in rapidly rising river discharge and associated velocities which sweep many smaller fish and 

invertebrates downstream. Manmade modifications to the river, primarily as a result of dam and hydroelectric 

structures, also create environments of higher or lower current velocities (Wlosinski and Supernant 2001). The 

ecological habits of several species require high sustained, or sudden, speeds. Northern pike, for example, 

present a fast, fusiform cross-section and demonstrate an “S”-start capability which allows very rapid, sudden 

movement to capture prey and escape predators (Schrieder and Hale 2004). Similarly, gar are built for very 

fast movements to capture food, although sustained speeds are generally much lower. At the opening to

forebays, fish must employee sudden, or burst, speed to effectively move away from the CWISs. While 

ecological factors such as life stage (e.g., adult versus juvenile) and habitat preference (e.g., benthic versus 

pelagic) play a role in individual vulnerability, total length appears to be particularly important to survival, with 

smaller fish more at risk than larger fish (Adam 2004). 

Burst swimming is defined as a short term (~20 seconds) anaerobic muscular contraction used by fish to

produce maximum acceleration (Wolter and Arlinghaus 2003). Burst swimming by fish is critical to avoiding 

patches of unusually fast current such as those that might be found in the forebays. Burst swimming is related 

to several morphological traits such as body shape, fin size, and musculature, but is strongly correlated with 

overall length (Wolter and Arlinghaus 2003, Figure 6). The relationships illustrated in the Figures 6 and 7 were 

shown to be reasonably applicable to most species and even to small representatives. Wolter and Arlinghaus 

(2003) reported that salmonids exhibited the highest swimming performance. Eels and sturgeons had a fairly 

low burst speed relative to their length. 
Report No. 10735-003-0200 3-7 September 2008

To determine whether the larger fish collected at the LOS should have been capable of escaping from the 

CWIS forebays, the Wolter and Arlinghaus model (Figure 6) was applied, using fish total length as the 

independent variable. The resulting burst speed calculations were compared to measured water velocities in 

the CWIS forebays, taken at the time of sample collection using a General Oceanics flow meter (Table 5). 

All of the larger fish could, hypothetically, achieve a burst speed that would allow them to escape from the 

forebays. In fact, using the same burst speed model from Wolter and Arlinghaus (2003), healthy fish longer 

than 5 cm should be able to escape from the forebays, given the speeds listed in Table 5. However, the water 

velocity measured at the time of sample collection may not be representative of overall forebay water velocity, 

particularly in deeper water. Eddies and microcurrents created by the concrete walls of the forebay and other 

underwater structures and barriers may yield significantly higher velocities as well as turbulent forces that 

overwhelm a fish’s ability to escape. Another important factor is water temperature. Batty and Blaxter (1992) 

found that the muscle contraction time for an escape response decreased at lower temperatures, as did tailbeat frequency, which determines how fast a fish can swim. A similar response was found in goldfish and 

killifish (Johnson and Bennett 1995). During colder months, therefore, small fish in the Missouri River may be 

more vulnerable to impingement, although such vulnerability is countered by overall lower activity. 

Despite the significance of the Wolter and Arlinghaus model (R2=0.77, p<0.001), the burst speeds of some of 

the species collected at LOS may fall below the response curve. Catfish, for example, being generally benthic 

feeders, may have lower burst speeds than more streamlined fish such as northern pike, gar and walleye. 

Even considering other factors that influence burst speed, interspecies variability or the maximum forebay 

intake velocity, the larger fish listed in Table 5 should have been able to escape. It is possible, therefore, that 

these fish were not healthy at the time of impingement and did not have the energetic resources needed to 

move away from the forebay. Some of them may have been dead prior to impingement (as is the likely case 

with some of the smaller fish as well). 

Although a species’ swimming speed is a key element in determining its impingement potential, there are 

many factors that are important including individual size, behavioral cues, feeding habits, preferred location 

within the water column and relative to the CWIS location, and the tendency to school. 

3.5 General Conclusions 

3.5.1 Life Stage and Taxonomy Data for all Species in the Garrison Reach are Well 

Understood. 

Fish species and populations in the Garrison Reach have been historically studied and continue to be 

evaluated several times annually by NDG&F. The information provided by NDG&F provides a good historical 

record of the kinds and numbers of fish present in the river new LOS and the seasonal fluctuations that fish 

populations may experience. The fish species that were found to be impinged at the LOS CWIS represent a 

subset of all the species collected by NDG&F, indicating that most species typical of the Garrison Reach are 

not routinely impinged. There did not appear to be any unusual or unexpected rates of impingement specific to 

one species or one operating scenario. During the year long impingement mortality study, there also weren’t 

any unique flow, temperature or habitat anomalies in this segment of the river. 

3.5.2 Life Stage and Taxonomy Data for all Species Collected in the Impingement Survey 

are Well Understood. 

All collected specimens were readily identified as to species and life stage. Most fish recovered from the 

collection basket were classified as dead, meaning that at the time of collection, there was no visible 

movement of the body, including gill covers, fins or tail. This did not necessarily mean that a fish was dead 

when impinged. In many cases, the fish appear to be in good shape when collected which means it may have 
Report No. 10735-003-0200 3-8 September 2008

been alive when impinged and subsequently died on the screens. At other times, fish were decayed, which 

suggests death prior to impingement. All specimens were counted and identified. 

Most collected specimens were identified as young of the year, based on weight and length. The majority of 

specimens were identified as forage species. 

3.5.3 The Species that are Most Commonly Impinged are Abundant in the Garrison Reach 

and Rare Species are Not Impinged. 

Throughout the sampling period, 16 species and a total of 397 individuals were collected; however, rainbow 

smelt, gizzard shad and emerald shiners were the most common species, comprising a total of 359 fish or 

90% of all the fish collected. As noted previously, these three species are considered forage species and are 

represented in the fish collected by NDG&F. 

3.5.4 Impingement Rates at LOS are Low and Impingement Mortality will have no LongLasting Consequences on the Populations of Impinged Species. 

Extrapolated impingement rates, based on the actual data collected from June 2005 to June 2006, are 

discussed in Section 4. Impingement rates for all species are considered to be very low; the highest rates are 

associated with the three forage species, rainbow smelt, gizzard shad and emerald shiner. Because of their 

relative abundance in the river, the effects or impacts of impingement losses from LOS on these populations 

has been, and will continue to be, negligible. 

3.6 Assessment of Data Sufficiency 

The results of this study may be used to assess the performance of the current CWIS as well as evaluate 

additional potential technologies and measures. The original Rule set out specific data requirements for a 

compliance demonstration study (Table 6). Even though the Rule has been suspended, Basin Electric believes 

that the historical data available on the Missouri River and its environs plus the data from the site-specific 

impingement mortality study will support the goals of any future rule that may require characterization. 
Report No. 10735-003-0200 4-1 September 2008

4.0 Data Interpretation 

4.1 Overview 

4.1.1 Taxonomic Identifications 

A list of the impinged species at LOS was presented in Table 2. As noted previously, 90% of the impinged 

individuals were rainbow smelt, gizzard shad and emerald shiners. When compared to the fish data collected 

by the NDG&F, it is interesting to note that many of the species collected by the agency never appeared on the 

screens at LOS. One of the most common species, the gizzard shad, was not found by NDG&F until the fall 

(September) of 2005 when a large number of gizzard shad were collected near the Stanton station. This was 

about the same time when gizzard shad were collected at LOS for the first time. This fall “run” of gizzard shad, 

therefore, was quantified by both the NDG&F and LOS CWIS data. 

While quantitative comparisons are difficult, it is apparent that many species that dominate the ambient 

samples from the river proper are poorly or not represented in impingement samples collected at LOS. The 

white sucker comprised over 19% of all the fish collected from 1997 to 2006 by NDG&F at the Stanton 

sampling location, while only 1 white sucker (0.3%) was collected at LOS. Similarly, while over 17% of the fish 

collected from 1997 to 2006 by NDG&F were river carpsuckers, this species was not found at all during the 

impingement mortality study at LOS. The differences in composition and frequency of fish known to be 

common in the Garrison Reach and those observed in the impingement samples are likely to be due to habitat 

preferences and/or escape potential. The collection methods and gear utilized in the ambient river studies 

have the potential to bias the results of the sampling event, making inter-survey comparisons difficult. 

4.1.2 Characterization of Lifestages 

The original Phase II rule called for the characterization of all stages that might be subject to impingement and, 

if appropriate, entrainment. This characterization may be necessary to ensure the full scope of any potential 

impact is understood and that any implications for selection of mitigation measures are known. Basin Electric 

believes that the general literature and the results of the impingement mortality study support an 

understanding of the potential impacts to all life stages. As importantly, the impingement mortality study was 

designed to facilitate understanding of diel and annual variations. 

4.1.2.1 Size of Impinged Organisms 

Life stages subject to impingement include all stages greater than the intake screen mesh size. The large 

majority of fish impinged at the LOS CWIS were small. More than 50% of the collected fish were classified as 

adults, based on their length and weight. The largest adult fish belonged to species of which very few were 

collected, such as channel catfish (6), cisco (1) and goldeye (1) (Figure 8). Adults of the most common fish 

were not substantially longer than young of the year (YOY), and generally did not exceed 10 cm in total length. 

Because of their inability to escape for forebays, small adults and YOY dominate those fish impinged on 

traveling water screens. Due to the placement of trash racks and debris screens on intake pipes, and due to 

their ability to out-swim intake approach velocities, larger organisms are not typically subject to impingement. 

4.1.2.2 Temporal Variations in IM 

Temporal variations in IM are the result of both biological factors (e.g., spawning season, migrations, etc.) and 

non-biological factors (e.g., river stage, plant operational status, etc.). Due to the multitude of factors that can 

potentially affect impingement mortality at a given location, temporal variations are difficult to ascertain. 

Specific knowledge of the waterbody, plant CWIS, and the dominant species in the area can allow temporal 

variations to be estimated. Much of this information is available from the literature. One obvious factor that 
Report No. 10735-003-0200 4-2 September 2008

can affect impingement mortality, and which takes precedent over biological factors, is the operational status 

of a plant. At LOS, typical water withdrawal does not vary with power demand. Pumping characteristics, such 

as suction and discharge head across the condensers, stimulates some variability in flow. In general, however, 

flow rates are constant over a wide range of electrical generation. It should also be noted that the data were 

collected during normal operating conditions and, therefore, do not reflect any bias associated with differential 

plant operation. 

Understanding of the temporal variations in impingement is important for two potential reasons: 

• In order to characterize accurately impacts of impingement mortality. For example, if impingement 

events were more significantly common during the night, failure to sample during both day and night 

would bias the daily estimates of impingement. Basin Electric believes that the existing data sets 

address this issue by inclusion of sampling throughout the year as well as both day and night 

conditions. 

• In order to assess whether periodic flow reduction might serve as a mitigation measure. For example,

if it can be demonstrated that impingement mortality occurs during a specific season and the plant can

be idled or run with reduced cooling water flow during that period, this might present an effective 

mitigation strategy. However, such a measure may prove to be wholly impractical from a load-serving 

requirement. At this point, Basin Electric is not able to commit to such operational measures. 

4.1.2.3 Seasonal Variation 

Spawning season is one of the most important biological factors affecting impingement mortality rates. 

Spawning times vary with species and are influenced by abiotic factors such as water clarity, total discharge 

and temperature. The primary period of reproduction and peak abundance of most Missouri River taxa is 

during the months of spring (typically March through May). Walleye, for example, typically spawn in April and 

May. Other species, however, spawn in the summer, fall or even winter. Spawning time for the emerald shiner 

is July to August; the cisco, of which only one specimen was found, spawns in November and December. 

Nevertheless, spring and summer remain the peak spawning and incubation periods and therefore these 

seasons would theoretically appear to be the most important seasons in regards to impingement as this is the 

time when larger populations would be present and small young would be hatched and locally present. Many 

of these organisms will be able to avoid entrainment later in the year as they grow larger and accelerate their 

swimming speeds and avoidance capabilities. The study data demonstrated that the greatest impingement 

rates occurred in the early winter months when certain species, e.g., gizzard shad, experienced “runs”. 

Data collected during the one year study completed at LOS were evaluated to determine seasonal variations 

in impingement rates. As noted previously, the winter months, from approximately mid November through the 

end of January, experienced the highest impingement rates for the three most common species. 

Biomass was also analyzed for seasonal differences. Biomass was variable, however much higher values 

were observed in the winter period (mid-November through late January) compared to the rest of the year. 

Total abundance showed similar trends with higher rates in the summer (mid-June through early August). 

4.1.2.4 Diel Variation 

The impingement study data was collected during both the day and night to enable an accurate assessment of 

the species and true impingement rates. However, much of the data were summarized on a daily 24-hour 

basis. 

Diel variations observed are most likely caused by species-specific daily patterns associated with rest and 

feeding periods. Organisms are much more active and mobile when feeding, and therefore have a higher 

chance of becoming impinged during these periods. Many invertebrates and vertebrates exhibit phototropic 

responses, moving vertically in the water column in response to daylight intensity (Wetzel 1983). Fish also 
Report No. 10735-003-0200 4-3 September 2008

demonstrate vertical and horizontal migration over a 24-hour period; in many cases this movement is a 

response to movement of food items. Emerald shiners, for example, tend to move into deeper waters during 

the day (Campbell and MacCrimmon 1970). Increased local fish migration often occurs in early morning and 

late afternoon and evening when food items are moving as well. 

4.1.3 Correlation Analysis 

As described in Section 4.1.2, there are several factors that can influence the number and size of fish 

impinged at LOS. Correlation analyses were conducted to determine if variability in the number of fish, or fish 

biomass, could be related to, or explained by, independent data obtained at the time of sample collection. 

Independent variables included plant load, air temperature, water temperature, water velocity, water flow 

(GPM), intake water volume (MGD) and depth of water in the forebay. Single variable linear regression

analyses were initially conducted, which showed that changes in the number of fish collected or the biomass of 

those fish were not readily explained by any single variable. Most coefficients of determination (r2) were less 

than 0.10. The best simple linear correlation for the number of fish was with air temperature (r2 = 0.14), which 

showed a negative relationship with the number of fish (Figure 9); the best correlation for biomass was with 

intake water volume (r2 = 0.12) (Figure 10). 

To determine whether very high biomass, occurring because of one or two exceptionally large fish or a large 

number of smaller fish, affected the outcome of the correlation analysis, data from nine events, when the 

biomass ranged from 272.5 to 763 g, were dropped from the dataset. Simple linear regression analysis was 

again completed, indicating that intake volume was the best independent variable, resulting in r2 values of 0.21 

for both number of fish and biomass (Figures 11 and 12, respectively). 

After running simple linear regression analyses, all variables were examined using stepwise regression

models, with forward selection and a selection criterion of p=0.05. Using the full dataset, the linear models did 

not provide a substantially improved explanation of dependent factor variability; only one variable was retained 

for both number of fish (air temperature) and biomass (intake volume). Using the reduced dataset, the r

2

 value 

for number of fish rose to 0.18, but again only retained intake volume. The biomass model using the reduced 

dataset retained both flow and water temperature as the best independent variables (r2 = 0.31). 

These analyses indicate that, while the amount of water passing through the forebay into the intake structure is 

probably the single most important variable affecting the number of fish impinged, even intake volume (daily or 

instantaneous) explains only a small portion of overall fish impingement variability. 

4.1.4 Documentation of Current IM Rates 

Upon evaluation of data distribution, it became apparent that because of occasional episodic events, the 

calculation of impingement rate should be based on mean values, not median values. (See the attached 

distribution analyses.) The calculations of impingement rate are as follows: 

“As Built” Impingement Rate

The “as built” calculation baseline for the year-long impingement study at LOS was based on extrapolating 

results from the 28, biweekly, 24-hour impingement sampling events conducted between mid June 2005 and

the end of June 2006. Daily results were expanded based on actual circulating water flows to yield an

impingement rate per million gallons and per 10,000 cubic meters (m3). These rates were then used to 

calculate a total impingement rate for the year based on actual water withdrawal. 

Total number of fish impinged during sampling (i.e., 28 days) = 397 

Total weight of fish impinged during sampling = 11.9 pounds 
Report No. 10735-003-0200 4-4 September 2008

Total volume of water withdrawn during sampling = 8319.4 million gallons 

Total annualized water withdrawal (actual) = 109,841.4 million gallons 

 = 4.15 x 108 m3 

Mean number of fish impinged = 0.05 per million gallons 

 = 0.12 per 10,000 m3 

Mean gram weight of fish impinged = 0.58 grams per million gallons 

 = 1.54 grams per 10,000 m3

Total estimated impingement, based on actual water withdrawal: 

5,492 fish per year 

 63,708 grams fish per year or 140.4 pounds 

Calculation Baseline by Design

This second impingement calculation baseline was based on extrapolating results used to derive the “as built” 

study estimate except that the daily impingement rates were expanded using the rated capacity of circulating 

water and service water pumps (330 MGD) rather than actual water use during the study period. This 

calculation approach results in the following: 

Total annualized water withdrawal (design) = 120,450 million gallons 

 = 4.56 x 108 m3

Mean number of fish impinged = .05 per million gallons 

 = .12 per 10,000 m3

Mean gram weight of fish impinged = 0.58 grams per million gallons 

 = 1.54 grams per 10,000 m3

Total estimated impingement, based on design water withdrawal: 

6,023 fish per year 

 69,861 grams fish per year or 154 pounds 

This calculation baseline estimate represents a 9.7% increase over the “as built” study estimate in numbers 

and biomass. The relative contributions to the total estimate at the taxa level are essentially the same 
Report No. 10735-003-0200 4-5 September 2008

between the “as built” and the design calculation baseline. The larger calculation baseline estimates, which 

are based on maximum pumping rates, reflect the difference between the rated capacity and actual water use, 

which totaled 91% of rated capacity during the year-long study. 

Impingement rates were estimated based on flow rate recorded during the study or by assuming the flow rate 

was at maximum plant capacity when flow rates were not available. Flow rates were standardized to 10,000 

m

3

 of water flow to allow extrapolation over time and to allow plant comparisons. These rates appear 

reasonable when compared to other impingement studies on large river systems. 

Potential impact to the Missouri River fisheries based on these rates is likely insignificant. 

4.2 Definition of Performance Basis 

The original 316 (b) Phase II Rule was specific in that it required an 80% reduction in IM from the Calculation 

Baseline. Although the rule was specific in that it established a quantitative reduction in IM, it should be noted 

that many NPDES permittees and regulatory agencies have historically taken more of an ecological approach 

in assessing performance basis as it relates to potential impact from CWIS. 

4.2.1 Target Species 

Some species have higher importance than others based on commercial/recreational importance, ecological 

importance, and protected status. After reviewing all of the available data, it was determined that no species 

warranted special attention. It is interesting to note that some species such as gizzard shad are often looked 

upon by the public, and sometimes the scientific community, as having limited value due to their ubiquitous 

nature and rapid growth which make them unsuitable as a food source for some game species. Although this 

species has ecological value and is a component to the food chain, population control of this species often 

occurs. Haines (2000), for example suggested biological control of gizzard shad by using predator fish 

species to manage and reduce impingement on cooling water intake screens. Similarly, gizzard shad are

often targeted in freshwater lakes/reservoirs across the United States by fisheries agencies, via lake

drawdown, to manage their populations. 

For the purpose of this IMECS, however, all species were treated with equal importance in estimating the 

performance basis. 

4.2.2 Calculation Baseline - Numbers vs. Biomass 

The 316(b) Phase II rule did not specify whether compliance with the IM performance standard should be

based on a reduction in fish abundance or biomass. For this reason, both were evaluated. 

The Proposal for Information Collection (PIC) for LOS proposed that the water/debris system provided 

approximately 10% potential “benefit” from EPA’s baseline situation. Otherwise, the LOS intake is similar to 

the EPA baseline situation. With a conservative estimate of an annual impingement rate of 6,023 fish and 

69,861 grams (154 pounds), the calculation baseline for LOS becomes: 

6,692 fish per year or 

 77,623 grams fish per year or 171 pounds 
Report No. 10735-003-0200 4-6 September 2008

4.3 Conclusions 

A review of available fish collection data (by electrofishing) from the North Dakota Game and Fish Department 

(NDG&F) revealed that the most common species collected during the impingement investigation (rainbow 

smelt, gizzard shad, emerald shiner) are collected at lower rates during electrofishing studies, where species 

such as walleye, river carpsucker and white sucker are more common. This difference is likely due, in a large 

part, to differences in collection methodology as well as fish size. Fish collected via electrofishing tend to be 

overwhelmingly larger (>20 cm in length) whereas impinged fish are much smaller (<10 cm in length). 

Impingement results for LOS show that Missouri River game species are seldom impinged and the most 

common impinged species are the small forage fish, many of which may originate from Lake Sakakawea. The 

small fish impinged at LOS, particularly rainbow smelt which were introduced into the lake as forage fish for 

salmonids, may be either dead, injured or weak when then reach the LOS CWIS, thus increasing the likelihood 

of impingement. The impingement results, therefore, were consistent with the kinds of fish that would be most 

susceptible to impingement in the source waterbody.

The calculation baseline for LOS, based on a year long impingement mortality study and design withdrawal 

rates, is 6,692 fish per year. The species, numbers of individuals and biomass potentially impinged at LOS is 

likely to be insignificant. 

4.3.1 Calculation Baseline - Abundance 

Calculation Baseline - Abundance

Randall et al. (1995) summarized numeric density for 143 rivers around the world. Mean density was 

determined to be 75,665 fish per hectare for all rivers combined and 132,247 fish per hectare for North 

American rivers. There is, however, substantial variability in fish production in North American rivers and 

lakes. Wetzel (1983) reports that biomass production for individual species can vary from less than 10 kg/ha/yr 

to over 900 kg/ha/yr, with an average of approximately 500 kg/ha/yr for total fish production in North American 

streams. 

Numeric density or biomass data for the channel border habitats of the Garrison Reach of the Upper Missouri 

River are not available, although the electrofishing data from NDG&F fish are (Table 1). It cannot be 

determined if the density for North American Rivers (132,000 organisms per hectare) (Randall et al. 1995) is 

reflective of conditions in the Garrison Reach. 

Reduction from Baseline - Abundance

Because quantitative data on baseline fish density of the Garrison Reach of the Upper Missouri River are not 

available, an accurate estimate of reduction from a baseline value cannot be calculated. However, data

gathered by NDG&F at their sampling site near Stanton can be examined to determine if any consistent trends 

in abundance are apparent (Figure 13). Those data show that, for the 9 years preceding the IM study, fish 

abundance has been relatively stable. The large spike in abundance in the fall of 2005 was due to a large 

number of gizzard shad collected only at that time. These data do not indicate any negative impacts on fish 

abundance from the LOS CWIS. 

4.3.2 Calculation Baseline - Species Richness 

Calculation Baseline – Species Richness

Fish collected by NDG&F at the Stanton sample location in the Garrison Reach from 1997 to the summer of 

2006 are listed in Table 1. In addition to those 35 species, another 21 species have been collected by NDG&F 

(through 2001) using electrofishing methods (NDG&F Fisheries Management Plan, Missouri River System 

2002-2007) (Table 7). Of the 56 resident species found in the Garrison Reach, only some would be likely to 

occupy the channel border area where the LOS CWIS is located. As described earlier in this document, some 
Report No. 10735-003-0200 4-7 September 2008

species prefer and/or spawn on shallow, sandy substrates but then migrate to deeper channel waters following 

spawning. Other species may spend more time near shallow, channel border areas, sand bars or in relatively 

secluded, protected locations, such as small side channels. Therefore, of the 56 species that are, or are likely 

to occur, in the region of the Missouri River near the LOS CWIS, only a portion would be commonly found near 

the CWIS. The reduction in species in the main channel and deeper channel border locations is due to 

several factors including the lack of suitable habitat, a vast increase in water velocity, turbidity and depth, and 

a reduction in nutrients and food supply for most species. In a study of the Mississippi River, Schramm (2004) 

identified 31 species that were thought to inhabit the main channel, including lamprey, sturgeon, paddlefish, 

gar, shad/herring, central stoneroller, grass carp, plains minnow, pearl dace, shiners, creek chub, suckers, 

smallmouth buffalo, redhorse, catfish, brook stickleback, and striped bass. Many of these species are also 

found in the Missouri River in Garrison Reach. 

Several species identified in the Garrison Reach will probably not be found in the near-bank location of the 

LOS CWIS. Of those that are, many of these individuals were probably only incidentally impinged during the 

IM study (such as white sucker and cisco), due to limited use of main channel habitat, or may have been dead 

prior to being impinged, as evidenced by their poor physical appearance at the time of recovery. It is also 

likely that the morphology of the Missouri River at the LOS location may contribute to the number and type of 

fish impinged. LOS is located on the outside of a substantial river bend as it changes direction from south to 

east. Current and inertia may carry small, injured and dead fish to the outside of the bend, near the 

western/southern bank, where they are more likely to be carried into the CWIS forebays. 

Since there are no quantitative data relative to the species that would most likely be found in the channel 

border area near the LOS CWIS intake on the Missouri River, a value of 56 species – the number collected by 

NDG&F – was used for the Calculation Baseline (based on species richness), representing the maximum 

number of species that could potentially inhabit the shoreline or channel border near LOS CWIS. All species 

collected during the one-year IM study at LOS are represented in this list (Table 7). 

Reduction from Baseline – Species Richness

In his study of the upper Mississippi River main channel Dettmers et al. (2001) determined the habitat was 

dominated by gizzard shad and freshwater drum (each represented 30% of the total), smallmouth buffalo 

(10%), channel catfish (9%), shovelnose sturgeon (5%), mooneye (4%) and common carp (3%). These seven

species account for over 90% of the fish in the Mississippi River main channel. Some species in the main 

channel of the Missouri River in the Garrison Reach are likely to be the same as in the Mississippi River, 

although electrofishing catches from the NDG&F at the Stanton station were dominated by white sucker, river 

carpsucker, gizzard shad, walleye, emerald shiner, common carp and shorthead redhorse. The gizzard shad 

was only collected once, in the autumn of 2005. Numerically dominant Missouri River species, therefore, 

appear to be demonstrably different than what is found in the Mississippi. While both represent very large lotic 

systems that have been significantly modified by dams and flood control systems, the Mississippi is much 

wider and deeper than the Missouri, especially the inter-reservoir segments of the upper Missouri. What is 

consistent between the Mississippi River studies and fish population data from the Missouri River is that both 

tend to be dominated by a relatively small number of taxa. 

Illinois Natural Heritage Survey (INHS) scientists, in collaboration with the USGS and the USACE, sampled the 

fishes in the main channel of the Mississippi River near Grafton, Illinois in 1996 with a specialized trawling 

vessel and 24 fish species were collected (INHS 1997). Abundant species included freshwater drum, channel 

catfish, gizzard shad, smallmouth buffalo, and carp. Other fishes caught less frequently in the main channel 

included the shovelnose sturgeon, lake sturgeon, and blue sucker. The researchers note that many of the fish 

use the main channel during the entire year such as gizzard shad, channel catfish, and smallmouth buffalo as 

they are suited for life in fast-flowing river conditions. Many other fishes use the main channel only seasonally. 

The study’s most diverse catches occurred in September and October when the river was at its lowest and 
Report No. 10735-003-0200 4-8 September 2008

temperatures were moderate. In these conditions, fish common to backwaters (e.g., bigmouth buffalo, 

shortnose gar and black crappie) can be found in the main channel. 

At the LOS 1 & 2 Plants, only three species represented over 90% of the organisms impinged 2005-2006. This 

suggests a significant reduction in species richness in the channel border areas near the CWIS compared to 

the 56 (Calculation Baseline) potential species that may inhabit this area. Lack of a food source could also 

play a factor in the spatial differences observed with the fisheries between habitats. Eggleton and Schramm 

(2004) compared feeding ecology and energetic relationships with habitat of blue catfish and flathead catfish. 

They concluded that caloric densities of consumed foods for both species are generally greatest in floodplain, 

intermediate in secondary river channels, and least in the main river channel. 

Both the samples of fish impinged at the CWIS and the NDG&F collections have also been dominated by a 

relatively small number of taxa. The reduction in richness of the fish impinged is likely related to size, health, 

ability to escape intake currents (burst speed) and habitat/food availability and preferences (leading to reduced 

densities in channel and channel border areas). All of these factors contribute to a situation where very few 

taxa are routinely available for possible impingement in the CWIS, resulting in no significant impact on the 

richness of the fish populations in this section of the upper Missouri River. 
Report No. 10735-003-0200 5-1 September 2008

5.0 References 

Adam, B. 2004. Avoidance of damages on downstream migrating fish by hydropower plants and inlet works.

Deutsche Tierarztliche Wochenschrift. 111(3):108. 

Analytical Software. 2003. Statistix 8. Analytical Software, Tallahassee, FL. 

Batty, R.S. and J.H.S. Blaxter. 1992. The effect of temperature on the burst swimming performance of fish 

larvae. J. Exp. Biol. 170:187-201. 

Bodola, A. 1966. Life History of the Gizzard Shad, Dorosoma cepedianum (LeSeur), Western Lake Erie. 

Fishery Bulletin. 65:391-425. 

Bowen, Z.H., K.D. Boveeand T.J. Waddle. 2003. Effects of flow regulation on shallow-water habitat dynamics 

and floodplain connectivity. Trans. Amer. Fish. Soc. 132(4):809-823. 

Campbell, J.S. and H.R. MacCrimmon. 1970. Biology of the Emerald Shiner Notropis atherinoides Refinesque 

in Lake Simcoe, Canada. J. Fish Biol. 2:259-273. 

Cross, F.B. and J.T. Collins. 1995. Fishes of Kansas. Univ. of Kansas Natural History Museum, Publ. 

Education Series No. 14, Lawrence, KS, 315 pp. 

Dettmers J.M., S. Gutreuter S., D.H. Wahl and D.A. Soluk. 2001. Patterns in abundance of fishes in main 

channels of the Upper Mississippi River system. Can. J. Fish. Aquat. Sci. 58:933-942. 

Eggleton, M.A. and H. L. Schramm, Jr. 2004. Feeding Ecology and energetic relationships with habitat of 

blue catfish, Ictalurus furcatus, and flathead catfish, Pylodictis olivaris, in the lower Mississippi River, 

U.S.A. Environ. Biol. Fishes 70: 107-121.

EPRI. 2003. Evaluating the Effects of Power Plant Operations on Aquatic Communities: Summary of 

Impingement Survival Studies. 

Everett, S.R., D.L. Scarnecchia and L. Fred Ryckman. 2004. Distribution and habitat use of sturgeon chubs 

(Macrhybopsis gelida) and sicklefin chubs (M. meeki) in the Missouri and Yellowstone Rivers, North 

Dakota. Hydrobiologia 527:183-193. 

Flore, L., H. Keckeis and F. Schiemer. 2001. Feeding, energetic benefit and swimming capabilities of O+ nase 

(Chondrostoma nasus L.) in flowing water: an integrative laboratory approach. Arch. Hydrobiol. Suppl. 

135:409-424. 

Galat, D.L., C.R. Berry, W.M Gardner, J.C. Hendrickson, G.E. Mestl, G.J. Power, C. Stone, M.R. Winston. 

2005. Spatiotemporal patterns and changes in Missouri River fishes. Proceedings of the American 

Fisheries Society Symposium. 45:249-291. 

Garner, P. 1999. Swimming ability and differential use of velocity patches by 0+ cyprinids. Ecol. Fresh. Fish 

8:55-58. 

Haines, D.E. 2000. Biological control of gizzard shad impingement at a nuclear power plant. Environmental 

Science & Policy 3 S275-S281. 

Illinois Natural History Survey (INHS). 1997. Understanding Large-river Fish Communities. 

http://inhs.uiuc.edu/chf/pub/surveyreports/sep-oct97/rivers.html
Report No. 10735-003-0200 5-2 September 2008

Johnson, T.P. and A. F. Bennett. 1995. The thermal acclimation of burst escape performance in fish: an

integrated study of molecular and cellular physiology and organismal performance. J. Exp. Biol. 

198:2165-2175. 

Lee, J. 2003. A Cold Connection. The Relationship of Rainbow Smelt and Coldwater Habitat in Sakakawea.

North Dakota Outdoors, April-May 2003:14-15. 

Miller, R.R. 1960. Systematics and Biology of the Gizzard Shad (Dorosoma cepedianum) and Related Fishes. 

Fishery Bulletin. 60:371-392. 

Pflieger, W.L. 1997. The Fishes of Missouri. Missouri Dept. of Conservation, Jefferson City, MO, 372 pp. 

Ross, S.T. 2001. Inland Fishes of Mississippi. Mississippi Dept. of Wildlife, Fisheries and Parks. 

Schramm, H.L., Jr. 2004. Status and Management of Mississippi River Fisheries. Pages 301-333 in R. 

Welcomme and T. Petr, editors. Proceedings of the Second International Symposium on the 

Management of Large Rivers for Fisheries. Volume 1. FAO Regional Office for Asia and The Pacific, 

Bangkok, Thailand. RAP Publication 2004/16. 

Schrieder, J.E. and M. E. Hale. 2004. Strikes and startles of northern pike (Esox lucius): a comparison of 

muscle activity and kinematics between S-start behaviors. J. Exp. Biol. 207:535-544. 

Scott, W.B. and E.J. Crossman. 1973. Freshwater Fishes of Canada. Fish. Res. Bd. Can., Bull. 184. 

Wakeling, J.M, K.M. Kemp and I.A. Johnston. 1999. The biomechanics of fast-starts during the ontogeny in the 

common carp Cyprinus carpio. J. Exp. Biol. 202:3057-3067. 

Wardle, C.S. 1975. Limit of fish swimming speed. Nature. 255:725-727. 

Wetzel, R.G. 1983. Limnology. 2nd Edition. Saunders College Publishing, Philadelphia767 pp + refs and index. 

Wlosinski, J.H. and C. Suprenant. 2001. Fish passage through dams on the Upper Mississippi River. U.S. Fish 

and Wildlife Service Technical Report. January 2001. 

Wolter, C. and R. Arlighaus. 2003. Navigation impacts on freshwater fish assemblages: the ecological 

relevance of swimming performance. Rev. in Fish Biol. and Fisheries. 13:63-89. 
Report No. 10735-003-0200 September 2008

Tables 
Report No. 10735-003-0200 September 2008

Table 1. Complete List of Fish Species Collected by North Dakota Game and Fish from 1997 to 

Summer 2006 at the Stanton Collection Site in the Garrison Reach 

Common Name Scientific Name 

Number of 

Years 

Collected 

Total 

Number of 

Fish 

Collected 

Percent 

of Total 

Bigmouth Buffalo Ictiobus cyprinellus 10 183 3.8 

Blue Sucker Cycleptus elongates 8 40 0.8 

Brown Trout Salmo trutta 4 28 0.6 

Burbot Lota lota 5 8 0.2 

Common Carp Cyprinus carpio 10 253 5.3 

Channel Catfish Ictalurus punctatus 8 30 0.6 

Cisco Coregonus artedi 1 7 0.1 

Common Shiner Notropis cornutus 1 9 0.2 

Cutthroat Trout Salmo clarki 4 23 0.5 

Emerald Shiner Notropis atherinoides 8 267 5.6 

Chinook Salmon Oncorhynchus tschawytscha 8 33 0.7 

Fathead Minnow Pimephales promelas 1 1 <0.1 

Freshwater Drum Aplodinotus grunniens 9 12 0.3 

Gizzard Shad Dorosoma cepedianum 1 640 13.4 

Goldeye Hiodon alosoides 7 23 0.5 

Johnny Darter Etheostoma nigrum 5 61 1.3 

Longnose Dace Rhinichthys cataractae 1 1 <0.1 

Longnose Sucker Catostomus catostomus 9 244 5.1 

Northern Pike Esox lucius 9 34 0.7 

Paddlefish Polydon spathula 2 3 0.1 

Rainbow Smelt Osmerus mordax 8 22 0.5 

Rainbow Trout Oncorhynchus mykiss 5 6 0.1 

River Carpsucker Carpiodes carpio 10 818 17.2 

Smallmouth Buffalo Ictiobus bubalus 6 56 1.2 

Sauger Stizostedion canadense 10 95 2.0 

Shorthead Redhorse Moxostoma macrolepidotum 9 259 5.4 

Smallmouth Bass Micropterus dolomieui 5 19 0.4 

Shortnose Gar Lepisosteus platostomus 5 10 0.2 

Shovelnose Sturgeon Scaphirhynchus platorynchus 5 18 0.4 

Spottail Shiner Notropis hudsonius 3 3 0.1 

Walleye Stizostedion vitreum 10 551 11.6 

White Bass Morone chrysops 6 91 1.9 

White Sucker Catostomus commersoni 10 913 19.2 

Western Silvery Minnow Hybognathus argyritis 1 1 <0.1 

Yellow Perch Perca flavescens 2 3 0.1 

Totals 4765 100 
Report No. 10735-003-0200 September 2008

Table 2. Species and Number of Fish Collected at LOS 

Species Total Number 

Collected 

Gizzard Shad 177 

Rainbow Smelt 132 

Emerald Shiner 50 

Longnose Sucker 13 

Channel Catfish 6 

Fathead Minnow 5 

Freshwater Drum 3 

Stonecat 2 

Tadpole Madtom 2 

Black Bullhead 1 

Carpsucker 1 

Goldeye 1 

Walleye 1 

White Sucker 1 

Shortnose Gar 1 

Cisco 1 
Report No. 10735-003-0200 September 2008

Table 3. Species and Number of Fish Collected at GRE 

Species Total Number 

Collected 

Rainbow Smelt 218 

Gizzard Shad 128 

Emerald Shiner 89 

Fathead Minnow 11 

Carpsucker 8 

Longnose Sucker 7 

Black Bullhead 4 

Goldeye 2 

Northern Pike 1 

White Sucker 1 

Channel Catfish 1 

Saugeye 1 

Stonecat 1 

Yellow Perch 1 
Report No. 10735-003-0200 September 2008

Table 4. Comparison of Survival of Some Fish Species on Screens with Continuous versus 

Intermittent Rotation (from EPRI 2003) 

Common Name 

% Survival 

(Intermittent 

Rotation) 

% Survival 

(Continuous 

Rotation) 

Blue catfish 20 

Threadfin shad 11 9 

Bay anchovy 1 29 

Freshwater drum 19 62 

Gizzard shad 11 9 

Skipjack herring 2 0 

Channel catfish 20 

Striped mullet 6 

Black crappie 0 10 

Largemouth bass 100 

White shrimp 81 

Brown shrimp 87 

Blue crab 56 80 

Gulf menhaden 14 

Atlantic croaker 0 50 

Sand weakfish 26 

Hardhead sea catfish 47 

Atlantic menhaden 8 0 

Menhaden (combined) 8 9 

Sticklebacks 0 

Alewife 2 0 
Report No. 10735-003-0200 September 2008

Table 5. Large Fish Collected at LOS CWIS and Calculation of Hypothetical Burst Speed 

Species Date/Event Total 

Length (in) 

Total 

Length (cm) 

Calculated 

Burst Speed 

(cm/s) 

Max Forebay 

Water Velocity 

(cm/s) 

Walleye 6/16/05 PM 16.54 42 158 66

Shortnose gar 7/13/05 PM 21.26 54 193 66 

Goldeye 8/10/05 AM 13.58 34.5 136 50 

Channel Catfish 11/16/05 AM 15.55 39.5 151 28 

Cisco 2/8/06 PM 15.75 40 152 22 

Channel Catfish 2/22/06 AM 16.54 42 158 21 
Report No. 10735-003-0200 September 2008

Table 6. Assessment of Data Sufficiency

Original 

Phase II Rule 

Citation 

Requirement 

Historical 

Data 

Source 

Data from 

Impingement 

Study 

Existing 

Data 

Adequate? 

125.95(b)(3)(i) 

Taxonomic identifications of all life stages of 

fish, shellfish, and any species protected 

under Federal, State, or Tribal Law (including 

threatened or endangered species) that are in 

the vicinity of the cooling water intake 

structure(s) and are susceptible to 

impingement and entrainment. 

SiteSpecific 

(sampling 

by ND 

G&F); 

Regional 

Literature 

Data indicates 

species most 

susceptible to 

impingement 

Yes 

125.95(b)(3)(ii) 

A characterization of all life stages of fish, 

shellfish, and any species protected under 

Federal, State, or Tribal Law (including 

threatened or endangered species) identified 

pursuant to paragraph (b)(3)(i) of this section, 

including a description of the abundance and 

temporal and spatial characteristics in the 

vicinity of the cooling water intake 

structure(s), based on sufficient data to 

characterize annual, seasonal, and diel 

variations in impingement mortality and 

entrainment. 

SiteSpecific(sa

mpling by 

ND G&F); 

Regional 

Literature 

Year long study 

with 24 hour 

collection periods 

provided sitespecific and 

comprehensive 

data on potential 

variations 

Yes 

125.95(b)(3)(iii) 

Documentation of the current impingement 

mortality and entrainment of all life stages of 

fish, shellfish, and any species protected 

under Federal, State, or Tribal Law (including 

threatened or endangered species) identified 

pursuant to paragraph (b)(3)(i) of this section 

and an estimate of impingement mortality and 

entrainment to be used as the calculation 

baseline. Impingement mortality and 

entrainment samples to support the 

calculations required in Section 

125.95(b)(4)(i)(C) and 125.95(b)(5)(iii) of the 

Rule must be collected during periods of 

representative operational flows for the 

cooling water intake structure and the flows 

associated with the samples must be 

documented. 

None 

Rates of 

impingement 

mortality have 

been quantified 

with the year long 

site-specific study. 

Yes 
Report No. 10735-003-0200 September 2008

Table 7. Fish Collected by NDG&F in the Garrison Reach and Number Collected During One-Year IM 

Study at LOS 

Fish Collected by 

NDG&F in Garrison 

Reach 

Number Impinged at 

LOS CWIS 

Fish Collected by NDG&F 

in Garrison Reach 

Number Impinged at 

LOS CWIS 

Banded Killifish Longnose Dace 

Bigmouth Buffalo Longnose Sucker 13 

Black Bullhead 1 Northern Pike 

Black Crappie Northern Redbelly Dace 

Bluegill Orangespotted Sunfish 

Blue Sucker Paddlefish 

Brassy Minnow Plains Minnow 

Brook Stickleback Pumpkinseed 

Brown Trout Rainbow Smelt 132 

Burbot Rainbow Trout 

Common Carp Red Shiner 

Channel Catfish 6 River Carpsucker 1 

Cisco 1 Sand Shiner 

Common Shiner Sauger 

Cutthroat Trout Shorthead Redhorse 

Emerald Shiner 50 Shortnose Gar 1 

Chinook Salmon Shovelnose Sturgeon 

Fathead Minnow 5 Smallmouth Buffalo 

Finescale Dace Smallmouth Bass 

Flathead Chub Spottail Shiner 

Freshwater Drum 3 Stonecat 2 

Gizzard Shad 177 Tadpole Madtom 2 

Golden Shiner Walleye 1 

Goldeye 1 White Bass 

Iowa Darter White Sucker 1 

Johnny Darter Western Silvery Minnow 

Lake Trout White Crappie 

Largemouth Bass Yellow Perch 
Report No. 10735-003-0200 September 2008

Figures 
Report No. 10735-003-0200 September 2008
Report No. 10735-003-0200 September 2008
Report No. 10735-003-0200 September 2008

Figure 3. Photographs of LOS CWIS

3A. Front of Intake at LOS CWIS 

3B. Trash Racks at LOS CWIS 

3C. Traveling Screens 
Report No. 10735-003-0200 September 2008

0

100

200

300

400

500

600

700

Bigmouth Buffalo

Black Bullhead

Blue Sucker

Brown Trout

Burbot

Carpsucker

Common Carp

Channel Catfish

Cisco

Common Shiner

Cutthroat Trout

Emerald Shiner

Chinook Salmon

Fathead Minnow

Freshwater Drum

Gizzard Shad

Goldeye

Johnny Darter

Longnose Dace

Longnose Sucker

Northern Pike

Paddlefish

Rainbow Smelt

Rainbow Trout

River Carpsucker

Smallmouth Buffalo

Sauger

Saugeye

Shorthead Redhorse

Smallmouth Bass

Shortnose Gar

Shovelnose Sturgeon

Spottail Shiner

Stonecat

Tadpole Madtom

Walleye

White Bass

White Sucker

Western Silvery Minnow

Yellow Perch

Species

Number of Fish

NDGF total NDGF Summer NDGF Fall

Figure 5. Totals on Each Sample Collection Date for the Three 

Most Abundant Fish Collected at Leland Olds

0

20

40

60

80

100

120

140

June 16June 29

July 13July 2

Aug 10

7

Aug 24

Sept 

Sept 

7

2

O

1

ct 10

Oct 1

Nov 

9

No

2

v 1

Nov 30

6

Dec 1De

4

c 2

Jan

8

11

Jan 25

Feb

F

 8

eb 22

Mar

Mar 22

8

Apr 

Apr 19

5

May 3

May 1May 31

7

June 14June 28

Collection Date

Number of Fish

Gizzard Shad

Emerald Shiner

Rainbow Smelt
Report No. 10735-003-0200 September 2008

Figure 6. Generalized model of burst speed of large fish as it relates to total length. From Wolter and 

Arlinghaus 2003.
Report No. 10735-003-0200 September 2008

Figure 7. Generalized model of burst speed of smaller fish (≤60 mm) as it relates to total length. 1) 

Wolter and Arlinghaus model, 2) Wardle (1975), 3) Wakeling et al. (1999) for carp, 4) Flore et al. (2001) 

for nose carp and Garner (1999) for 5) roach and 6) dace. 
Report No. 10735-003-0200 September 2008

Figure 8. Average total length of adults and YOY collected at 

the LOS CWIS

0

5

10

15

20

25

30

35

40

45

Black bullhead

Carpsucker

Channel Catfish

Cisco

Emerald Shiner

Gizzard Shad

Goldeye

Longnose Sucker

Rainbow Smelt

Stonecat

Freshwater Drum

White Sucker

Species

Total Length (cm)

Adult

YOY

Figure 9. Relationship between Number of Fish Collected (all 

data) and Air Temperature

y = -0.2267x + 17.885

R

2

 = 0.1419

-10

0

10

20

30

40

50

60

70

80

0 20 40 60 80 100 120

Air Temperature (F)

Number of Fish
Report No. 10735-003-0200 September 2008

Figure 10. Relationship between Fish Biomass (all data) and 

Plant Intake Volume

y = 0.6748x - 90.911

R

2

 = 0.1214

-100

0

100

200

300

400

500

600

700

800

900

0 50 100 150 200 250 300 350 400

Intake Volume (MGD)

Biomass (g)

Figure 11. Relationship between Number of Fish Collected 

(excluding high biomass events) and Plant Intake Volume

y = 0.0178x - 0.2252

R

2

 = 0.2079

0

2

4

6

8

10

12

14

0 50 100 150 200 250 300 350 400

Intake Volume (MGD)

Number of Fish
Report No. 10735-003-0200 September 2008

Figure 12. Relationship between Fish Biomass (excluding 

high biomass events) and Plant Intake Volume

y = 0.1105x - 9.4475

R

2

 = 0.2081

0

10

20

30

40

50

60

70

80

90

100

0 50 100 150 200 250 300 350 400

Intake Volume (MGD)

Biomass (g)

Figure 13. Number of Fish Collected by NDG&F at Stanton 

each Season

0

100

200

300

400

500

600

700

800

900

1000

1997-Sum

1997-Fall

1998-Sum

1998-Fall

1999-Sum

1999-Fall

2000-Sum

2000-Fall

2001-Sum

2001-Fall

2002-Sum

2002-Fall

2003-Sum

2003-Fall

2004-Sum

2004-Fall

2005-Sum

2005-Fall

2006-Sum

Sampling Period

Number of Fish

No Data
Report No. 10735-003-0200 September 2008

Appendix A 

November 15, 2007 Letter from NDDH
Report No. 10735-003-0200 September 2008

Appendix B 

Literature Review Bibliography 

(Some references may be the same as in Section 5 of this report) 
Report No. 10735-003-0200 September 2008

Berry, C. R. and B. A. Young. 2001. Introduction to the benthic fishes study. Volume 1 of Population structure 

and habitat use of benthic fishes along the Missouri and lower Yellowstone rivers. U.S. Geological 

Survey, Cooperative Research Units, South Dakota State University, Box 2140b, Brookings, South 

Dakota 57007. charles_berry@sdstate.edu. 

Berry, C. R., D. L. Galat, and M. L. Wildhaber. 2001. Fish distribution and abundance. Volume 3 of Population 

structure and habitat use of benthic fishes along the Missouri and Yellowstone rivers. U.S. Geological

Survey, Cooperative Research Units, South Dakota State University, Box 2140b, Brookings, South 

Dakota 57007. charles_berry@sdstate.edu. 

Dieterman, D. J., M. P. Ruggles, M. L. Wildhaber, and D. L. Galat, editors. 1996. Population Structure and 

Habitat Use of Benthic Fishes Along the Missouri and Lower Yellowstone Rivers. 1996 Annual Report 

of Missouri River Benthic Fish Study PD-95-5832 to U.S. Army Corps of Engineers and U.S. Bureau 

of Reclamation. 

Dieterman, D.J. 2000. Spatial Patterns in Phenotypes and Habitat Use of Sicklefin Chub, (Macrhybopsis 

meeki) in the Missouri and Lower Yellowstone Rivers. Doctoral Dissertation, University of MissouriColumbia, Columbia, MO 185 p. 

Everett, S. R., D. L. Scarnecchia, and L. F. Ryckman. 2004. Distribution and habitat use of sturgeon chubs 

(Macrhybopsis gelida) and sickle-fin chubs (M. meeki) in the Missouri and Yellowstone Rivers, North 

Dakota. Hydrobiologia 527: 183-193. 

Galat, D. L., M. L. Wildhaber, and D. J. Dieterman. 2001. Spatial patterns of physical habitat. Volume 2 of 

Population structure and habitat use of benthic fishes along the Missouri and lower Yellowstone rivers. 

U.S. Geological Survey, Cooperative Research Units, University of Missouri, 302 ABNR Bldg., 

Columbia, Missouri 65251-7240. galatd@missouri.edu. 

Galat, D., R. White, C. Pierce, L. Sappington, D. Scarnecchia, M. Ruggles. Missouri River Benthic Fish Study. 

http://wfs.sdstate.edu/units/fishes.html. 8 pp. 

Hendrickson, J. C. 2004. North Dakota Fisheries Investigations. Aquatic Investigations of the Missouri

Mainstem in North Dakota. Report of the North Dakota Game & Fish Department, Bismarck, North 

Dakota: 85 pp. 

Hesse, L. W., J. C. Schmulbach, J. M. Carr, D. D. Keenlyne, D. G. Unkenholz, J. W. Robinson, G. E. Mestl. 

1989. Missouri River Fishery Resources in Relation to Past, Present, and Future Stresses, p. 352-

371. In D.P. Dodge [ed.] Proceedings of the International Large River Symposium. Can. Spec. Publ. 

Fish. Aquat. Sci. 106. 

Hesse, L. W. and W. Sheets. 1993. The Missouri River Hydrosystem. Fisheries 18(5): 5-14. 

Neel, J. K. 1978. Life in the Missouri River with Warming by 676 Megawatts Gross Steam Generated Power

Production. Prepared for Basin Electric Power Cooperative. 

Pegg, M. A. 2000. Hydrological variation along the Missouri River and its effect on the fish community. 

Doctoral Dissertation, Iowa State University, Ames, IA. 141 pp. 

Pierce, C. L., C. S. Guy, P. J. Braaten, and M. A. Pegg. 2001. Fish growth, mortality, recruitment, and 

condition and size structure. Volume 4 of Population structure and habitat use of benthic fishes along
Report No. 10735-003-0200 September 2008

the Missouri and lower Yellowstone rivers. US. Geological Survey, Cooperative Research Units, Iowa 

State University, Science Hall II, Ames, Iowa 50011. cpierce@iastate.edu. 

Power, G. 1993. The Missouri River System’s “Other” Fish. ND Outdoors, August, p. 6-9. 

Power, G., J. C. Hendrickson, J. D. Lee, and F. Ryckman. 1994. North Dakota Fisheries Investigations, 

Missouri River System Fishery Reference and Operational Management Document. NDG and F 

Dept., 100 North Bismarck Expressways, Bismarck, ND, 58501-5095. 72 pp. 

Power, G. 1995. River Fish. ND Outdoors, March, p. 13. 

Power, G. 1998. The Missouri River in North Dakota (Garrison Reach) – A Report to the Director, Official 

Department Position Papers, Game and Fish Department, North Dakota: 7 pp. 

Welker, T. L. 2000. Ecology and Structure of Fish Communities in the Missouri and Lower Yellowstone Rivers. 

Doctoral Dissertation, University of Idaho, Moscow, ID. 232 p. 

Young, B. A., T. L. Welker, M. L. Wildhaber, C. R. Berry, and D. Scarnecchia, editors. 1997. Population 

Structure and Habitat Use of Benthic Fishes along the Missouri and Lower Yellowstone Rivers. 1997 

Annual Report of Missouri River Benthic Fish Study PD-95-5832 to the U.S. Army Corps of Engineers 

and the U.S. Bureau of Reclamation. 

Young, B. A. 2001. Intraspecific Variation among Emerald Shiners (Notropis atherinoides) of the Missouri 

River. Doctoral Dissertation, South Dakota State University, Brookings, SD. 140 p.
Report No. 10735-003-0200 September 2008

Appendix C 

Summary of Data Collected through June 2006