Colfax RFQ Attachments .pdf

ATTACHMENT 1

Project Feasibility Report and Environmental Assessment

Red Cedar River, Dunn County Wisconsin Continuing Authorities Program Section 14

Emergency Stream Bank Protection

Colfax Waste Water Treatment Lagoons

Feasibility Report and Environmental Assessment

Doc Version: Final Feasibility Report

29 July 2016

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Table of Contents

1.0 Introduction

1.1 Purpose of the Report

1.2 Project Location

1.3 Project Authority and Scope

1.4 Problem and Planning Objective

2.0 Inventory Existing and Forecast Future Conditions

2.1 Hydraulic and Hydrologic Conditions

2.2 Geological Conditions

2.3 Natural Resources Conditions

2.3.1 Aquatic and Wetland Resources

2.3.2 Terrestrial Natural Resources

2.3.3 Threatened and Endangered Species

2.4 Cultural Resource Conditions

2.5 Socio-economic Conditions

2.6 Future Without Project Conditions

3.0 Alternatives

3.1 No Action

3.2 Riprap

3.3 Relocation of Wastewater Facility

3.3 Other Alternatives Considered

3.4 Comparison and Evaluation of Alternatives

3.5 Description of Recommended Plan

3.6 Recommended Plan Cost Estimate

4.0 Environmental Effects

4.1 Natural Resource Effects

4.1.1 Air Quality

4.1.2 Surface Water Quality

4.1.3 Aquatic and Wetland Resources

4.1.4 Terrestrial Natural Resources

4.1.5 Threatened and Endangered Species

4.2 Cultural Resource Effects

4.3 Social and Economic Effects

4.3.1 Noise

4.3.2 Aesthetics

4.3.3 Recreation

4.3.4 Safety

4.3.5 Economy and Employment

4.3.6 Environmental Justice

4.3.7 Public Facilities and Services

4.4 Cumulative Effects

5.0 Environmental Compliance and Review

5.1 Applicable Environmental Laws and Executive Orders

5.2 Clean Water Act (Section 404 and 401)

5.3 Fish and Wildlife Coordination Act, Endangered Species Act

5.4 Cultural Resources Coordination

5.5 Environmental Justice

5.6 Migratory Bird Treaty Act

5.7 Bald and Golden Eagle Protection Act

6.0 Coordination, Public Views, and Comments

7.0 Summary and Conclusions

8.0 Works Cited

Figures:

Figure 1. Project Location, Village of Colfax, WI

Figure 2. Colfax CAP 14 Project Site

Figure 3. Discharge-Frequency Curves

Figure 4. HEC-RAS Model Schematic

Figure 5. Colfax Project Site, Failing South Bank, Habitat Example (November 2015)

Figure 6. Colfax Stabilization Plans

Figure 7. Colfax Site Section

Figure 8. Construction Impacted Areas

Figure 9. Karner Blue Butterfly Occurrences Observed in Wisconsin

Figure 10. Northern Long-Eared Bat Interim 4(D) Rule

Figure 11. Bald Eagle Nest, Eastern End of Project Alignment (November 2015)

Tables:

Table 1. Project First Cost Estimate for Riprap

Table 2. Project First Cost Estimate for Relocation of Wastewater Treatment Facility

Table 3. Project First Cost Estimate for Alternative Plans

Table 4. Project First Cost Estimate

Table 5. Environmental Assessment Matrix

Appendices:

Appendix A – Hydraulics and Hydrology

Appendix B – Real Estate

Appendix C – Civil Engineering

Appendix D – Geotechnical Engineering and Geology

Appendix E – Cost Engineering

Appendix F – Agency Coordination

Appendix G – Public Involvement

Appendix H – 404(b)(1) Evaluation

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1.0 Introduction

1.1 Purpose of the Report

The purpose of this Corps of Engineers (Corps) feasibility study and integrated Environmental Assessment (EA) is to formulate a plan to stabilize the riverbank adjacent to the Colfax Wastewater Treatment Lagoons in the Village of Colfax, Wisconsin and to evaluate the potential effects of such action. This report provides planning, engineering, and preliminary construction details of the recommended plan to allow final design and construction to proceed subsequent to the approval of the plan and funding for construction.

The report documents existing conditions, project future conditions, assesses the problem, provides and compares alternatives, and makes a recommendation to accomplish the emergency streambank protection.

1.2 Project Location

The project area is a portion of the riverbank adjacent to the embankment of the Village’s wastewater treatment lagoon, less than one mile downstream of the Village of Colfax, Wisconsin. The site is on the left descending bank of the Red Cedar River in Dunn County, Wisconsin (Figure 1). The Village of Colfax is located in north central Wisconsin, approximately 75 miles east of St. Paul, Minnesota.

Continuing Authorities Program Section 14 Colfax Wastewater Treatment Lagoons, Dunn County, Wisconsin

Figure 1. Project Location, Village of Colfax, WI.

1.3 Project Authority and Scope

The project is authorized under Section 14 of the Flood Control Act of 1946, as amended;

Emergency Streambank Protection. This project is authorized under the Continuing Authorities Program (CAP), and is designed to implement projects to protect public or non-profit public facilities and/or services which are open to all on equal terms, have been properly maintained but threatened by natural processes on stream banks and shorelines and are essential and important enough to merit Federal participation in their protection (ER 1105-2-100, F3).

The scope of the study will encompass a 50-year planning horizon for the area of erosion on the river immediately adjacent to the wastewater treatment lagoons (Figure 2).

Figure 2. Colfax CAP 14 Project Site.

1.4 Problem and Planning Objective

The Colfax Wastewater Treatment facility along the Red Cedar River is threatened by river bank erosion. The lagoons were constructed in 1982. The river is actively meandering within its floodplain and erosion has progressed to within 50-feet from the edge of the wastewater treatment ponds, posing a potential water quality hazard and threatening downstream ecosystems, including Tainter Lake located 6 miles downstream. According to one report (Red

Cedar River Erosion and Habitat Assessment Report 2014) the Red Cedar River erosion rate for years 1992 – 2012 is approximately 1.0 feet/year and 0.5 feet/year near the wastewater treatment lagoons.

Problem: Ongoing erosion on the bank of the Red Cedar River is threatening the wastewater treatment lagoons.

The objective of the study is to review and analyze data and develop a plan to protect the wastewater treatment lagoons from eroding into the Red Cedar River.

2.0 Inventory Existing and Forecast Future Conditions

The following describes the current conditions of the study area as well as projections about the future without project conditions. The future without project conditions establish a baseline condition upon which to later compare the effects of potential bank stabilization measures.

2.1 Hydraulic and Hydrologic Conditions

Discharge-frequency curves for the Red Cedar River at Colfax are shown in Figure 3. One curve is based on the Flood Insurance Study (FIS), Dunn County and Incorporated Areas, December 2, 2011. The discharge-frequency curve for the FIS was developed based on a statistical analysis of 54 years of record at the USGS gage located just upstream of Colfax from a May 1963 St.

Croix and Dunn County Soil Water Conservation District report. The other curve shown in Figure 3 is from the “Red Cedar River Erosion and Habitat Assessment Report, March 14, 2014.”

This curve was developed based on a statistical analysis of the period of record from 1914 through 1990 and estimated peaks for missing and more recent years. The estimated peaks were based on a regression equation developed using the concurrent record for the Colfax USGS gage and the USGS gage on Hay River at Wheeler, Wisconsin. Hay River is a tributary of the Red Cedar River that enters downstream of Colfax. The USGS also performed a discharge-frequency analysis at the Colfax gage based on just the period of record data from 1914 to 1990. This analysis was presented in “Flood-Frequency Characteristics of Wisconsin Streams, Water Resources Investigations Report 03-4250” and the results are very similar to the assessment report.

The HEC-RAS model for the Red Cedar River used for the FIS was a converted HEC-2 model and did not have a cross section in the vicinity of the ponds. Therefore, a small geo-referenced HEC- RAS model of the Red Cedar River was developed in the project vicinity. A schematic of the model is shown in Figure 4. Cross sections were based on the FIS model, surveyed cross sections in the vicinity of the ponds and LiDAR data. The surveys and LiDAR data were provided by Dunn County and the Natural Resources Conservation Service. Starting water surface elevations for the model were based on a rating curve developed from the FIS HEC-RAS model results. Discharges used in the model were based on the Red Cedar River Erosion and Habitat Assessment Report. Additional information related to hydraulics and hydrology can be found in Appendix A – Hydrology and Hydraulics.

Figure 3. Discharge-Frequency Curves.

Figure 4. HEC-RAS Model Schematic.

2.2 Geological Conditions

Site geology for the project area is based on the Natural Resources Conservation Service soil survey for Dunn County, Wisconsin. That information identifies the upper six feet of material at the site as sandy loam, loamy fine sand, gravelly loamy, and/or stratified gravelly course sand.

These materials are conducive to erosion.

The project site has steep channel banks varying between 1V:1.5H and 1V:2.5H, likely due to a combination of toe and surface runoff driven erosion. Erosion of the channel toe is driven by the river, which can cause the material above the toe to slide to a more energetically favorable grade. Erosion due to surface runoff from above the channel appears to flow down the bank at several locations, which can cause material from the upper bank to migrate down into the river.

Left uncorrected, erosion is likely to continue its progression along the channel bank.

Rock vanes were placed in the river at some time in the past to stabilize the bank, but the vanes have mostly been undermined as the bank continued to erode.

Additional information related to site specific geological conditions can be found in Appendix D

– Geotechnical Engineering and Geology. A Phase 1 Hazardous Toxic Radioactive Waste analysis has been completed for the project area and can be found in the Phase 1 HTRW Report.

2.3 Natural Resources Conditions

2.3.1 Aquatic and Wetland Resources

The Red Cedar River flows primarily southwest through Barron and Dunn Counties before heading predominately west near the project site. The river drains approximately 1,480 square miles upstream of the project site, and flows into Tainter Lake approximately 6 miles downstream of the project. Tainter Lake is a hypereutrophic impoundment with summer algae blooms and poor water quality as a result of high phosphorus loads (Wisconsin Impaired Waters List WBIC 2068000). Summer algal blooms severely impact the recreational use of the lake. The lake also is impacted by a rapidly expanding sediment delta where the Red Cedar River enters the impoundment (Tainter Menomin Lake Improvement Association 2014).

Tainter Lake also is impacted by two invasive species: curly-leaf pondweed (Potamogeton crispus) and the Chinese mystery snail (Bellamya chinensis). The Red Cedar River at the project site is impaired with mercury in fish tissue, and high total phosphorus (Wisconsin Impaired Waters List WBIC 2063500).

The fishery of the Red Cedar River consists primarily of warm water species, including species such as white sucker, redhorse species, buffalo, smallmouth bass, walleye, sauger and northern pike. Shovelnose Sturgeon have been historically present in the river, but the dam at Menomin Lake (approximately 10 river miles downstream) blocks their access to spawning habitat.

Bank erosion has been occurring at the project site and on high banks throughout the reach.

Sediment that has entered the river has been transported to Tainter Lake where it is contributing to delta formation. Approximately 8% of the storage capacity of the impoundment has been lost over its lifetime.

Wetlands within the project area are limited to the lower portions of the stream bank near the ordinary high water mark. Most of the stream bank has a steep gradient into the river channel and leaves little area for wetland vegetation growth. However, a short distance upstream from the project alignment (approximately 50’) is a larger stream bench that likely contains wetland vegetation.

2.3.2 Terrestrial Natural Resources

The project area falls within the State of Wisconsin’s Western Coulee and Ridges Ecological Landscape which is a mix of forest (41% of total cover), agriculture (36%), and grassland, with wetlands mostly restricted to the river valleys. The primary forest cover is oak-hickory, while maple-basswood forests are common in cooler, moist areas. Bottomland hardwoods occur in the valley bottoms of major rivers. Relict conifer stands are rare, and are associated with steep-faced outcrops with cool microclimates (Wisconsin DNR 2012).

The soils of the project site are predominately sandy loam. The soil is well drained and highly erodible. The project site along the southern bank of the Red Cedar River consists of non-native regularly mowed grasses on the slope of the wastewater treatment facility, and the north facing bank of the Red Cedar River, which is steep with a mix of bare ground, grasses and forbs, and trees and shrubs (includes red oak, aspen, white pine, red cedar, silver maple, sumac and dogwood). The project site is disturbed by frequent human activity.

Due to the significant level of human activity and surrounding agricultural land use practices of the area, wildlife species expected to be present are those adapted to living in proximity of human settlement and intense agriculture (Figure 5). Coyotes, deer, small rodents and various species of resident and migratory birds may be present.

Figure 5. Colfax Project Site, Failing South Bank, Habitat Example (November 2015).

2.3.3 Threatened and Endangered Species

Two federally-listed endangered species and one threatened species are known to occur in Dunn County: sheepnose mussel (Plethobasus cyphyus), endangered; gray wolf (Canis lupus), endangered; and northern long-eared bat (Myotis septentrionalis), threatened. The endangered Karner blue butterfly (Lycaeides melissa samuelis) has not been observed in Dunn county but its habitat is known to exist in the area.

There is no designated critical habitat for any of these species near the project site.

The sheepnose, a freshwater mussel, was historically found across the Midwest and southeast, but is now only located in 25 streams. The sheepnose life cycle includes a parasitic stage where the larvae are attached to gills or fins of sauger (Stizostedion candense) allowing them to be moved to various parts of a stream network and then deposited on the streambed to grow and reproduce. The sheepnose are typically found in large rivers and streams in the shallow areas with moderate to swift currents that flow over course gravel and sand.

The gray wolf is a habitat generalist that occupies a wide range of habitats where large ungulates are found. As pack animals they defend territories from 25 to over 1,000 square miles. Territory size is a function of prey density. As both males and female wolves disperse from packs they have been known to range distance greater than 600 miles.

The northern long-eared bat may roost in cavities, underneath bark, in crevices, or in the hollows of both live and dead trees. The northern long-eared bat is susceptible to white-nose syndrome which has resulted in population declines up to 99 percent in affected areas.

The Karner blue butterfly requires early successional habitats, primarily oak savannas and pine barrens, but can also be found in prairies and human altered habitats. The Karner blue butterfly is dependent on wild lupine (Lupinus perennis L.) as the only known food source for its larval stage. As adults the Karner blue butterfly require nectar plants for food sources.

The bald eagle (Haliaeetus leucocephalus) is a large bird of prey that lives near rivers and lakes where they forage for fish and other riparian species. The bald eagle has been removed from the threatened and endangered species list but still has special protections under the Bald and Golden Eagle Protection Act.

Additional information on the likelihood of these species being found within the project site is provided in Section 4.1.5.

In addition to the federally listed species, the state of Wisconsin compiles a list of species on their Natural Heritage Inventory. There is a possibility that state listed species could be present at the project site. Coordination with Wisconsin DNR has been ongoing and best practices to reduce impacts to state listed species will be taken into consideration. A review of the state listed mussel species indicates that a state mussel species of concern, the Elktoe (Alasmidonta marginata) was sampled at a site upstream from the project site in 1994, and could be present at the project site (Kelner 1994). The state list for Dunn County is included in Appendix F – Agency Coordination for further reference.

2.4 Cultural Resource Conditions

The project area is within the Central Plains geographical province, characterized by gently rolling hills and outwash plains typical of ground moraines (e.g., Martin 1965). In this portion of Dunn County, older drift overlies Cambrian age sandstones that formed in the Hollandale Embayment, part of an epicontinental sea (Attig et al. 1988; Clayton et al. 2006). The older glacial till were likely deposited during the Illinoian Glaciation (ca. 130-200,000 years before present [bp]). However, the margins of more recent glacial ice were within approximately 20 miles of the project area. Accordingly, the project area would have enjoyed periglacial conditions as Wisconsin glacial ice advanced and retreated between 70,000 to 14,500 bp, where meltwater streams were active, permafrost was present, and loess production and transport underway (Dyke et al. 2003). Such a landscape was likely denuded of vegetation for the most part until tundra was established following ice disintegration. Holocene climate fluctuations allowed a boreal forest to develop, followed by mixed conifer and hardwood taxa.

Currently, the project area resides within a tension zone separating the floristic provinces of the northern hardwoods to the north and the prairie-forest to the south (e.g., Curtis 1959).

The project area is situated on an outwash terrace of the Red Cedar River. Sediments are dominated by sandy loam, sand and gravels that developed under mixed deciduous forests, and prairie vegetation (cf. oak savannah) (NRCS 2015). No buried soil horizons are mapped within the project area. The project area consists of eroding streambank nearly devoid of vegetation, the top of the bank (i.e. terrace) that contains a two-track road that consists of alternating areas of fill or borrow running between the streambank and sewage lagoons, staging areas situated on manicured lawns around the sewage lagoons, and a disposal area located within an active quarry.

A variety of cultural resources investigations have been conducted in the greater area, most centered along the Red Cedar River. These include investigations for housing developments, bridge reconstruction, pipelines and hydroelectric facilities, and impoundment drawdowns (WISHPO 2015). Portions of the project area were surveyed prior to the construction of the wastewater treatment lagoons (McNair 1981). Although a number of cultural resources were identified in the project area by local informants, including ‘arrowheads,’ no cultural resources were identified during the 1981 investigations. In addition, the top portion of the bank has been disturbed by cutting (i.e., borrow) and filling activities associated with construction of the sewerage lagoons and perimeter berms/roadways. This includes installation of an outfall pipe along the western portion of the project area. The eroded streambank escarpment is mostly bare soil while the terrace tread harbors a variety of grasses and some woody vegetation. The areas immediately south of the steep bank consist of manicured lawn adjacent to the lagoon berms. The disposal site is an active quarry/material storage area. In any event, subsequent construction of the lagoons and recent erosion of the channel bank would have destroyed any archaeological phenomenon in and around the project area.

Human habitation in western Wisconsin coincides with the retreat of glacial ice proximal to the project area, beginning with the Paleo tradition (ca. 15,000-8,000 bp). Continual occupancy ensues throughout the Archaic (ca. 8,000-2000 bp), Woodland (ca. 2,000-1,000 bp), Oneota (1,000-400 bp) and Prehistoric periods (400-500 bp) (e.g., Benchley, et al 1997; Green et al 1986). Following French, British and American traders, the project area was surveyed in 1848 and the community of Colfax established in 1864 relying on a lumber and agricultural economic base (BOPC 2015; VOC 2015).

The nearest cultural resources to the project area is a burial mound group (47DN19) approximately one and a half miles to the west, the National Register of Historic Places (NRHP) listed Colfax Municipal Building (WHI # 16820), erected in 1916, and the NRHP eligible Soo Line Railroad Depot (WHI # 28494) constructed in 1914. Both of the historic standing structures are located within the Village of Colfax and are approximately three-quarters of a mile distant from the project area (WHS 2015).

2.5 Socio-economic Conditions

The Village of Colfax, Wisconsin is the closest population center to the project (0.5 miles). The Village of Colfax has a population of 1,158 in 478 households, and 524 housing units as of the 2010 Census. The median household income was $40,417 in 2010, approximately 17.7% of the population was below the poverty level. City population has been relatively stable since the 1980 Census with an average annual growth rate from 1980 to 2010 of 0.3%.

2.6 Future Without Project Conditions

The future without project would involve no Federal action to stabilize the bank at the wastewater treatment facility. The future condition assumes that there would be continued erosion of the bank at the wastewater treatment facility, ultimately leading to bank failure. The current rate of erosion near the wastewater treatment lagoons is estimated to be approximately 0.5 feet per year.

Failure of the bank could result in the wastewater ponds breaching and posing a potential water quality hazard and threatening downstream ecosystems, including Tainter Lake located 6 miles downstream. Failure of the bank could also result in the Village of Colfax not having the capacity to adequately treat its wastewater. If the bank were to fail the Village would immediately contact the Wisconsin Department of Natural Resources regarding contamination implications and then take immediate action to repair the failure.

The lagoons and associated facilities were constructed in 1982 and have been operated and maintained by the Village. Maintenance activities include keeping the area and embankments mowed and free of weeds and daily inspections of the facility. No major repairs have been required since the lagoons were constructed. The lagoons are large enough to nearly double the daily intake capacity. Currently the only maintenance item to be addressed is removal of sludge.

3.0 Alternatives

Several action alternatives were considered and evaluated in addition to taking no action. The initial array of measures included relocating the wastewater treatment facility, use of rock vanes, riprap toe and bank protection, bio-engineering measures, and bank shaping and excavation. Brief descriptions of the final array of alternatives and approximate costs are provided below. For more in depth descriptions of the alternatives including further alternatives considered but screened out, please see Appendix A – Hydrology and Hydraulics.

3.1 No Action

The No Action alternative is synonymous with no Federal Action. The No Action alternative would allow the erosion to continue and could potentially lead to complete bank failure and failure of one or more of the three wastewater treatment ponds, resulting in the release of sewage effluent into the Red Cedar River. There is no cost estimate associated with the No Action alternative as no action would be taken that would incur Federal costs.

3.2 Riprap

This alternative involves placing riprap on the streambank to the 10% annual exceedance flood elevation to prevent erosion along the approximately 1,300 linear feet of eroding bank, which would significantly reduce the potential for bank failure at the treatment facility. The design due to the site conditions and the value of the infrastructure being protected. Since this alternative was screened out early no cost estimate was developed.

Bank Shaping: All alternatives where the bank above the toe protection was allowed to reach a natural angle of repose were considered and screened out. This approach assumes that bank sloughing would continue at the site to allow the bank to reach a stable condition. The bank would continue to slough above the toe protection and the extent of the sloughing could potentially grow large enough to destabilize portions of the treatment ponds before a stable, natural angle of repose would become established. The collective risks to the wastewater treatment ponds were considered too great to move forward with this alternative. No cost estimate was developed for this alternative.

Riprap vanes: Riprap or rock vanes were not considered because they were tried at this site previously and were not successful. There are remnants of rock/riprap vanes at the project site. There are three on the west side of the site spaced about 140 feet apart and the distance from the most upstream of these three to the one farthest upstream is about 420 feet. Based on this, it appears there were originally six rock/riprap vanes spaced about 140 feet apart and the remnants of two cannot be seen. Based on inspection of the remaining vanes, it appears they were undermined and have fallen into the river over time. Additionally, riprap vanes were screened out due to the depth of the flow, height of the bank and that the upper bank could not be cut back to a stable slope using riprap vanes. Given that remnant vanes were unsuccessful and the site is unsuitable for implementation of vanes, riprap vanes were screened out from further consideration. Since this alternative was screened out no cost estimate was developed.

3.4 Comparison and Evaluation of Alternatives

Following ER 1105-2-100 Appendix F section F-23.d., the formulation and evaluation of the alternative plans should focus on the least cost alternative. The least cost alternative plan is considered justified if the total cost of the proposed alternative is less than the cost to relocate the threatened facility (ER 1105-2-100). The recommended plan must also meet the planning objective, which is to protect the threatened public infrastructure for the 50-year planning horizon. The following table (Table 3) summarizes the cost estimates for each alternative.

Figure 6. Colfax Stabilization Plans.

Figure 7. Colfax Site Section.

area near the site entrance that has been previously used as an earthen material storage site which could be used to dispose of any leftover soils removed from the reshaping of the slope (Figure 8).

Figure 8. Construction Impacted Areas.

4.1 Natural Resource Effects

4.1.1 Air Quality

The operation of construction equipment may result in a short-term localized reduction in air quality. Adverse effects would be limited and short-term because they are associated only with construction. It is estimated that construction could take up to one year, though additional time may be needed given site conditions and construction logistics.

Greenhouse gas emissions and their effect on climate change are global issues resulting from numerous and varied sources, with each source making a relatively small addition to global atmospheric greenhouse gas concentrations. Additionally, the ability to accurately predict the localized or short-term effects of changes in greenhouse gas emissions is extremely limited.

Nevertheless, it is imperative for agencies to identify the potential emissions from project alternatives when it may inform the agency’s decision-making.

The proposed project would be expected to produce greenhouse gasses during project activities in the form of exhaust from various types of machinery used for material transport and material placement. The Council on Environmental Quality (CEQ) revised draft NEPA guidance for consideration of the effects of climate change and greenhouse gas emissions in December, 2014 (http://go.usa.gov/3KEyR). The guidance proposed a level of 25,000 metric tons or more of CO2-equivalent GHG emissions annually as an indicator that detailed assessment of greenhouse gasses may be meaningful to decision makers and the public. Based on the scope of the project and the amount of material required to move and construct the project it is expected that the metric tons of CO2-equivalent greenhouse gas emissions will be far below the threshold set by the CEQ guidance. Therefore, a detailed analysis of greenhouse gas emissions is not required, and has not been prepared for the proposed alternative.

4.1.2 Surface Water Quality

The proposed action would have no long-term negative effect on water quality of the Red Cedar River. Preventing future bank erosion at the project site from transport downstream could have a minor positive effect on sediment deposition in Tainter Lake downstream. Water quality, especially water clarity, may be briefly reduced during construction. Any reduction in clarity would fade immediately following construction.

Existing water quality impairments in the Red Cedar River and downstream at Tainter Lake have been identified for dissolved oxygen, total phosphorus, and fish bioassessments. Short-term changes in turbidity and phosphorus load levels could occur as the result of construction activities. Placement of riprap and grading actions could result in short-term increases in turbidity and phosphorus load as a result of disturbing bottom sediments. To minimize this impact, construction activities will be conducted in compliance with necessary permit requirements, to include compliance with any conditions of the state water quality certification section 401 of the Clean Water Act. This will include use of best management practices, or BMPs, and potentially other measures to minimize short-term impacts. The specific construction methods, including identification of specific BMPs, have not yet been identified.

These will be further specified during the plans and specifications phase. Potential BMPs may include construction during low-flow periods, use of silt curtains, vegetation plans to minimize vegetation clearing, minimizing the time period of exposed soils, control of stormwater flow from any upland areas disturbed during construction, and other methods. Given the Corps’ prior experience with similar bank stabilization projects and its success in controlling short-term turbidity impacts from construction of those projects, it is reasonable to assume that no significant impacts would occur to water quality. BMPs have traditionally been successfully used to minimize short-term impacts associated with projects that focus on grading and rock placement along streams and rivers. Further, to the extent necessary, the section 401 water quality certification may be conditioned on implementation of measures designed to reduce water quality impacts, and the Corps will ensure any such measures are implemented.

Erosion at the riprap boundary would be minimized with careful design and construction. The riprap boundary will be designed to blend back into the bank, minimizing turbulence at the riprap/bank interface that could result in long-term erosion. Over the long term, stabilization of the eroding bank should minimize the amount of sediment entering the Red Cedar River at the project site.

Construction activities would not be expected to substantially change dissolved oxygen concentrations. Impacts to fish and invertebrates are discussed further below, but would not be expected to be significant.

The No Action alternative would have substantial adverse impacts to water quality. Under the No Action alternative the bank at the project site would continue to erode and may lead to bank failure. Failure of the bank could result in the wastewater ponds breaching and posing a potential water quality hazard.

4.1.3 Aquatic and Wetland Resources

The proposed action would result in the placement of riprap along the outside bend of the river. The extent of the proposed riprap is estimated at less than 1.3 acres. Riprap would be placed up to an elevation that approximates a 10% annual discharge exceedance frequency (i.e., 10% chance exceedance flood event). Thus, much of the 1.3 acres impacted by the riprap placement would be above areas typically considered aquatic habitat (e.g., areas below the ordinary high water mark, or approximately a 50% chance annual exceedance discharge event).

The project would include about 1,300 lineal feet of riprap placed along the river bank.

Invertebrates could be crushed by placement of the riprap, but they would quickly recolonize the new rock substrate. Fish may avoid the area during construction but would return upon completion. The new riprap may attract fish and provide some low level of habitat value. No long-term adverse impacts would be anticipated to aquatic habitat or biota. The project would not contribute toward the long-term impairments for fish and invertebrates. The proposed action should stabilize the streambank, reduce probability of bank failure and erosion of bank materials, and in turn benefit Red Cedar River aquatic habitat.

While the proposed project would reduce the likelihood of bank erosion on the steep bank on the south bank of the Red Cedar River at the project site, it is possible that changes in flow velocity could result in channel adjustments to cross sectional area at the project site or downstream at rates different than current trends. The proposed action would harden the southern bank by adding riprap over the existing slope and to a small degree to the south bank portion of the channel bed. The addition of riprap in the channel would reduce the channel cross sectional area and could marginally speed up flows for a period of time. Induced higher velocities within the project area would result in channel adjustments up and downstream as the reach achieves dynamic equilibrium. If this did happen, it would be relatively minor, and would most likely occur in channel and towards the north bank of the river, which is not steep, currently stable, has good ground cover and not adjacent to any infrastructure that would be negatively impacted. The most likely scenario is that the river will adjust itself naturally, with very little impact to the north river bank, while the proposed riprap on the south bank will protect the area from continued erosion and bank instability. A natural adjustment in this section of the river would result in increased sediment transport downstream of the project.

This increase in sediment transport would result in limited and temporary increase in deposition on the downstream point of the sandbar islands located near the project site.

The only area of wetlands near the project site that were identified during a site visit are a short distance upstream from the project alignment (approximately 50’). These wetlands would not be impacted by downstream construction under the proposed plan.

The reach immediately downstream of the project could be impacted by the project, as banks in this section of the river have experienced erosion over the river’s history. Aerial imagery indicates that the river reach immediately downstream is highly sinuous and has undergone continuous changes in its flow path throughout its history. While the hardening of the bank at the project site may allow the stream to have marginal excess stream power in the downstream reach, changes to the downstream erosion rates should be minimal.

The No Action alternative would have substantial adverse impacts to aquatic habitat. Under the No Action alternative the bank at the project site would continue to erode and may lead to bank failure. Failure of the bank could result in the wastewater ponds and threatening downstream ecosystems.

4.1.4 Terrestrial Natural Resources

The aerial footprint extent of the proposed project, including the access corridor, is estimated at approximately 2 acres (planar area). The proposed action would result in the clearing of trees and understory vegetation within the area of riprap placement and slope above the riprap to allow the slope to be reduced to a lower grade. Trees to be lost range in size from many 1-2” diameter aspen to several large silver maple with diameter over 12.” Some of these trees may be lost to erosion even if no action is taken. Large white pines (diameter at breast height >12’) at the eastern end of the project site will be left standing. Otherwise, long-term impacts of the project would be minimal. Wildlife may temporarily avoid the project area during construction, but would return following construction. The access corridor would be allowed to fully revegetate. Material removed from slope reshaping may be deposited at the disposal site near the entrance to the treatment plant. If this occurs, it is not likely to significantly alter existing conditions as the disposal site currently has numerous large piles of exposed earthen material. The materials would be exposed, but surrounding vegetation and an existing depression at the disposal site ensure deposited materials are unlikely to move from the site.

No long-term adverse impacts would be anticipated to terrestrial habitat or biota outside of the immediate stabilization site.

4.1.5 Threatened and Endangered Species

Sheepnose mussels have not been identified on the Red Cedar River near the project site.

Sheepnose mussels have been found in the Chippewa River of which the Red Cedar River is a tributary. The Chippewa River confluence is approximately 28 miles downstream from the project site. Sheepnose mussels require a suitable population of sauger to carry the larval stage of its life cycle upstream. The dams at Menomin and Tainter lakes are between known sheepnose populations and the project site. These dams do not allow fish passage, so sauger downstream from the dams are prohibited from carrying the sheepnose larval stage upstream to the project site. Furthermore the population of sauger in the Red Cedar River above the project site is likely limited by the degraded water quality in Tainter Lake.

Gray wolves have historically been identified in Dunn County. A gray wolf was killed approximately 8 miles from the project site in 2011. It is possible that individuals of this species may move through the proposed project area but high road density, proximity to the Village of Colfax and a high percentage of land in agricultural production in the project area are not conducive to wolf use. The project should have no impact on gray wolves.

The Karner blue butterfly (KBB) requires early successional habitats, primarily oak savannas and pine barrens, but can also be found in prairies and human altered habitats. The KBB is dependent on wild lupine (Lupinus perennis L.) as the only known food source for its larval stage. As adults, the KBB can use several nectar plants for food sources. Mowing can be used to maintain a habitat in an early successional state, but frequent mowing of the type historically done at the wastewater treatment facility are not conducted with the goal of allowing wild lupine growth and have likely reduced the potential of the property to support wild lupine or other nectar plants needed for the KBB. Recent site visits have not found indication of wild lupine presence. In addition, several studies have developed range maps indicating KBB likely current range (Figure 9). There were no observed occurrences of the KBB within Dunn County, but there have been observed populations in Eau Claire County approximately 15 miles from the project site. Successful dispersion distances for the KBB of greater than 1.4 miles are likely rare (FWS 2003). While the project site has a possibility to be managed to support KBBs, the current extent of the known KBB range, short dispersion distances, and low quality habitat indicate the project will have no effect on the KBB.

Figure 9. Karner Blue Butterfly Occurrences Observed in Wisconsin.

The northern long-eared bat may inhabit the project area in early spring through mid-fall. They may roost in cavities, underneath bark, in crevices, or in the hollows of both live and dead trees. The northern long-eared bat is susceptible to white-nose syndrome which has resulted in population declines up to 99-percent in affected areas. The project site is within the FWS Final 4(d) rule white-nose syndrome buffer zone, and as such the project site is likely within 150 miles of a northern long-eared bat hibernacula with confirmed white nose syndrome (Figure 10). The project does have numerous species of trees and of the sizes that they could be used by northern long-eared bats during roost which will be removed for construction. None of the trees to be removed are currently known to be maternity roost trees (FWS Horton, A pers.

comm.). Only trees directly impacting construction of the stabilized bank will be removed. All trees to be removed will be removed outside of the northern long-eared bat summer maternity season (June 1st - July 31st) to avoid direct impacts to the species.

Figure 10. Northern Long-Eared Bat Interim 4(D) Rule.

Bald eagles are likely to inhabit the project site periodically for nesting in addition to foraging for food. Local observers have witnessed bald eagles using a nest in a large white pine on the eastern edge of the project site each year (figures 8 and 11). Bald eagle nesting through fledgling in Wisconsin normally occurs from January through August. The emergency nature of the bank failure at the site does not allow the construction to be completed entirely outside of this timeframe. This nest site will not be removed or damaged during construction. The nest will be near construction activities, and bald eagles using the nest would likely be disturbed by the construction activity and noise. This disturbance could lead to nest abandonment during the construction season. The nest will be left intact and future nesting bald eagles may return to the site. The close proximity of the nest site to the failing bank does not allow most of the best management practices (distance buffers, maintaining forested areas between the nest and activities, or avoiding activities near the site during the breeding season). USACE has been and will continue to be in contact with the USFWS to determine what if any best management practices could be implemented to reduce impact to bald eagles during construction. Through discussion with USFWS it has been determined that coordination will occur prior to construction to determine the need for a bald eagle non-purposeful take permit.

disposal area is within an active quarry and material storage area that has been cut into the earth’s surface. No cultural resources were identified.

The likelihood that intact, significant archaeological phenomena exist within the project area is remote. Because the streambank protection works will face the Red Cedar River there will be no visual effects to historic properties, such as the standing structures within the Village of Colfax (the area opposite the eroding streambank currently hosts a variety of trees). The Corps has determined that the project has little potential to cause effects on historic properties.

4.3 Social and Economic Effects

4.3.1 Noise

Heavy equipment used for construction will generate noise. This noise may bother nearby residents. However, this impact will be short-term and relatively minor.

4.3.2 Aesthetics

Site preparation and the placement of materials for bank stabilization will result in a minor intrusion on the visual aesthetic environment. Construction activities will be short-term and relatively minor. The permanent placement of riprap will be a permanent intrusion. However, the area of placement would be a relatively short stretch of river, and the overall impact will be minor. The reshaping of the slope should allow more vegetation to grow above the riprap than the existing steep and eroding slope allows.

4.3.3 Recreation

Use of the Red Cedar River for fishing and canoeing near the project site could be inconvenienced during construction. There is a canoe landing near the Village of Colfax approximately 0.5 river miles from the project site. Public shore fishing access is not accessible through the project site, but anglers using canoes could be minimally impacted during construction at the site. The proposed bank stabilization will have no permanent, long-term impacts on the recreational environment.

Under the No Action alternative, recreational activities such as fishing, canoeing and boating could be substantially adversely impacted due to continued erosion of the bank and the threat of the waste water lagoons spilling into the river.

4.3.4 Safety

During construction, there would be an increase in heavy equipment traffic adjacent to the project site. To maintain safety at the project site, the project area could be temporarily closed to public access during construction. These effects would be attenuated through the appropriate placement of construction and safety signage or other safety measures. These effects would be short-lived and terminate when construction is complete.

The proposed action will not have long-term adverse effects on public safety at the site. In fact, the project will help protect the integrity of the wastewater treatment facility, which would provide an improvement to its safe use.

Under the No Action alternative public safety would be substantially adversely impacted if the waste water lagoons were to spill into the river.

4.3.5 Economy and Employment

The proposed bank stabilization will have negligible impacts on the socioeconomic environment of the Village of Colfax or the larger Dunn County. It is possible that construction activity could result in a minor short-term infusion of income into the local economy due to purchase of materials from local vendors or employment of persons from the local area, particularly if the construction work is awarded to a local contractor.

4.3.6 Environmental Justice

Environmental justice is a national goal and is defined as the fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies. The proposed project would be constructed on public lands; no private lands would be acquired. Public involvement, via distribution of information concerning the proposed project, has and will continue to be an integral part of planning for this project to ensure that concerns of all people will be fully considered in the decision making process. No adverse economic or social effects would be anticipated under the proposed action or the No Action alternative.

Neither alternative would disproportionately impact any one group over another.

4.3.7 Public Facilities and Services

The proposed action will not have long-term adverse effects public facilities or services. In fact, the project will help protect the integrity of the wastewater treatment plant, which would provide an improvement to its safe use. The No Action alternative could have a substantially adverse effect on public services if erosion were to continue on the project site to the point of imminent failure of the wastewater treatment facility resulting in it being unavailable for continued safe operation.

4.4 Cumulative Effects

Cumulative impacts on the environment are the result of the incremental impacts of past actions, the proposed project and reasonably foreseeable future actions. Significant changes to the environment were made through road construction and development within the project area. This project is intended to provide long-term stability to failing infrastructure. Effects of the construction would be minimal and mostly positive in maintaining the quality of the human environment. The proposed action will help protect the integrity of the Village of Colfax waste water treatment facility. The current facility usage is at approximately 65% capacity (Village of Colfax 2015). The proposed action will not affect the biodiversity of the area or permanently fragment the habitat above existing conditions. It also would not contribute to any long-term adverse social or economic effects. Reasonably foreseeable future actions not associated with the project include the management of the surrounding land parcels in conditions similar to the existing conditions. The Village of Colfax population trends are of little to no growth over the next 30 years (Village of Colfax 2015). The Village of Colfax anticipates the need for an additional 17 residential properties, and limited commercial or industrial growth up to 4 acres by the year 2040 (Village of Colfax 2015). Downstream from the project location, Tainter Lake, may experience some residential growth if water quality improvements were made allowing the lake to become more marketable to recreational use.

5.0 Environmental Compliance and Review

5.1 Applicable Environmental Laws and Executive Orders

The proposed action would comply with Federal environmental laws, Executive Orders and policies, and applicable State and local laws including but not limited to the Clean Air Act, as amended; the Clean Water Act, as amended; the Endangered Species Act of 1973, as amended;

the Fish and Wildlife Coordination Act of 1958, as…