Please note that comment letters submitted to the MPCA do become public documents and will be part of the official public record for this project.

Transcription

1 June 3, 2005 TO: INTERESTED PARTIES RE: Rushmore Wastewater Treatment Facility Enclosed is the Worksheet (EAW) for the proposed Rushmore Wastewater Treatment Facility, Nobles County. The EAW was prepared by the Minnesota Pollution Control Agency (MPCA) and is being distributed for a 30-day review and comment period pursuant to the Environmental Quality Board (EQB) rules. The comment period will begin the day the EAW availability notice is published in the EQB Monitor, which will likely occur in the June 6, 2005 issue. Comments will be accepted through July 6, In addition to the EAW, the Minnesota Pollution Control Agency s draft National Pollutant Discharge Elimination System (NPDES) will also be available for public comment concurrently, beginning June 6, The contact person for the NPDES Permit is Jim Strudell at (651) Comments received on the EAW will be used by the MPCA in evaluating the potential for significant environmental effects from this project and deciding on the need for an Environmental Impact Statement (EIS). A final decision on the need for an EIS will be made by the MPCA Commissioner after the end of the comment period. If a request for an EIS is received during the comment period, or if the Commissioner recommends the preparation of an EIS, the MPCA Citizens Board (Board) will make the final decision. The final EIS need decision will also be made by the Board if so requested by the project proposer, other interested parties or MPCA staff and if this request is agreed to by one or more members of the Board or the MPCA Commissioner. The Board meets once a month, usually the fourth Tuesday of each month, at the MPCA office in St. Paul. Meetings are open to the public and interested persons may offer testimony on Board agenda items. A listing of Board members is available on request by calling (651) Please note that comment letters submitted to the MPCA do become public documents and will be part of the official public record for this project. If you have any questions on the EAW, please contact Lynne Kolze of my staff at (651) Sincerely, Beth G. Lockwood Supervisor, Environmental Review Unit Environmental Review and Operations Section Regional Division BGL:jgo Enclosure

2 ENVIRONMENTAL ASSESSMENT WORKSHEET Note to reviewers: The Worksheet (EAW) provides information about a project that may have the potential for significant environmental effects. This EAW was prepared by the Minnesota Pollution Control Agency (MPCA), acting as the Responsible Governmental Unit (RGU), to determine whether an Environmental Impact Statement (EIS) should be prepared. The project proposer supplied reasonably accessible data for, but did not complete the final worksheet. Comments on the EAW must be submitted to the MPCA during the 30-day comment period which begins with notice of the availability of the EAW in the Minnesota Environmental Quality Board (EQB) Monitor. Comments on the EAW should address the accuracy and completeness of information, potential impacts that are reasonably expected to occur that warrant further investigation, and the need for an EIS. A copy of the EAW may be obtained from the MPCA by calling (651) An electronic version of the completed EAW is available at the MPCA Web site 1. Project Title: Rushmore Wastewater Treatment Facilities Improvement 2. Proposer: City of Rushmore 3. RGU: Minnesota Pollution Control Agency Contact Person Coleen Gruis Contact Person Lynne Kolze and Title City Clerk and Title Project Manager Address 136 North Thompson Avenue, P.O. Box 227 Address 520 Lafayette Road North Rushmore, Minnesota St. Paul, Minnesota Phone (507) Phone (651) Fax (507) Fax (651) Reason for EAW Preparation: EIS Scoping Mandatory EAW X Citizen Petition RGU Discretion Proposer Volunteered If EAW or EIS is mandatory give EQB rule category subpart number and name: Minn. R. ch , subp Project Location: County Nobles City/Twp City of Rushmore, Onley & DeWald Townships 1/2 NE 1/4 Section 25 Township 102N Range 42W 1/2 SE 1/4 Section 24 Township 102N Range 42W N 1/2 1/4 Section 30 Township 102N Range 41W S 1/2 1/4 Section 19 Township 102N Range 41W TDD (for hearing and speech impaired only): (651) Printed on recycled paper containing 30% fibers from paper recycled by consumers

3 Figures and Table attached to the EAW: Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Table 1 State map showing project location United States Geological Service topographic map showing project location Aerial photo and site plan Map showing discharge locations Letter from Sarah Hoffman, Minnesota Department of Natural Resources (MDNR), regarding Natural Heritage Database Inquiry Map showing general locations of designated critical habitat for the Topeka Shiner transmittal from Laurie Fairchild, U.S. Fish and Wildlife Service, regarding Topeka Shiner Letter from Joe Oschwald, MDNR, regarding: Protected Waters Temporary and Permanent Erosion Control Plans Letter from Britta Bloomberg, Minnesota Historical Society (MHS), regarding Historic and Archaeological Sites Rushmore wastewater existing discharges 6. Description: a. Provide a project summary of 50 words or less to be published in the EQB Monitor. The city of Rushmore (City), Nobles County, is proposing to expand their existing wastewater treatment facility (WWTF) from the existing design flow of 47,270 gallons per day (gpd) to 99,000 gpd. The project involves constructing a new lift station, stabilization pond, and force main. b. Give a complete description of the proposed project and related new construction. Attach additional sheets as necessary. Emphasize construction, operation methods and features that will cause physical manipulation of the environment or will produce wastes. Include modifications to existing equipment or industrial processes and significant demolition, removal or remodeling of existing structures. Indicate the timing and duration of construction activities. Background The City s existing stabilization pond WWTF was constructed in The WWTP consists of a lift station, 6,000 lineal feet of four-inch diameter force main, two primary treatment ponds, one secondary treatment pond, and related piping and control structures. The two existing primary ponds each have a surface area of 2.8 acres at mean operating depth, and a maximum operating depth of five feet. The secondary treatment pond has a surface area of 3.0 acres at mean operating depth, with a maximum operating depth of five feet (Figures 1-2). In its present configuration, the lagoon system has a permitted Average Wet Weather Design Flow (AWWF) of 47,270 gpd. However, the actual amount of wastewater discharged from the WWTF is currently exceeding the conditions of the National Pollutant Discharge Elimination System (NPDES) Permit. Flows often exceed 100,000 gpd. Due to the fact that the WWTF consistently does not meet permit limits, the MPCA has issued a compliance schedule requiring the City to bring the WWTF into compliance with its NPDES Permit. One important part of the compliance schedule requires the City to address the infiltration and inflow (I/I) of ground water to the sewage collection system. Proposed Project Rushmore, Minnesota 2 Worksheet

4 The City proposes to expand the existing wastewater treatment system to better handle higher flows. The expansion would require the construction of a new primary treatment pond. The pond would be built adjacent to the existing ponds on property that is currently used for crop farming. The project would convert approximately 11.9 acres from agricultural use to non-agricultural use. The new primary lagoon cell would have a maximum operating water depth of six feet, a minimum operating water depth of two feet, and a surface area of approximately 7.5 acres, at mean operating depth. The storage volume of the new pond would be 9.72 million gallons, which would increase the AWWF to 99,000 gpd. The upgraded system would enable the existing primary treatment ponds to be converted to secondary ponds, and to discharge, through the existing discharge outfall. A geotechnical consultant has determined that the new pond would have to be sealed with a layer of clay to reduce the leakage of water to soils below the pond. The MPCA has determined that new ponds must not leak water in an amount that exceeds 500 gallons per acre per day. At this leakage rate it has been determined that ground water will not be adversely impacted. The proposed WWTF improvements also include the construction of a new lift station, new six-inch diameter force main, new piping, and control structures. Rehabilitation of some sewer manholes, repair of some sewer main defects, and reduction of tile drain and sump pump inflows are also included in the project to further reduce the infiltration and inflow of ground water into the sewage collection system. Approximately 6,500 linear feet (L.F.) of six-inch diameter force main adjacent to West (Ivers) Avenue and 260th Street would be installed to replace the existing four inch force main. The force main along West Avenue would be laid near the edge of the road and would be installed using directional boring techniques, as much as practical. Directional boring the pipe underground eliminates the need to disturb surface soil or pavement. The railroad crossing would be constructed by boring and jacking so that a steel casing can be installed for the force main. The force main along 260th Street would be located in a ditched area, installed by traditional trenching techniques (Figure 3). The existing force main and lift station would continue to be maintained as a back-up system. Construction activities are expected to commence during the late summer and fall of 2005, and be completed by late fall of 2005 or spring of Construction dates are tentative and dependent on the availability of funding. c. Explain the project purpose; if the project will be carried out by a governmental unit, explain the need for the project and identify its beneficiaries. The purpose of the project is to provide effective wastewater treatment to the City. The beneficiaries of the project would be those served by the collection system as well as individuals within the watershed. This project would eliminate bypasses of untreated and partially treated wastewater to surface water. This project would serve 179 homes within the City. At design flow, the expanded WWTF would serve 190 homes. Additional expansions of the WWTF are not anticipated given that population growth in the community is projected to be relatively stable over the next 20 years. d. Are future stages of this development including development on any outlots planned or likely to happen? Yes No If yes, briefly describe future stages, relationship to present project, timeline and plans for environmental review. e. Is this project a subsequent stage of an earlier project? Yes No Rushmore, Minnesota 3 Worksheet

5 If yes, briefly describe the past development, timeline and any past environmental review. The City s existing WWTF was constructed in Project Magnitude Data Total Project Area (acres) 14 acres or Length (miles) Number of Residential Units: Unattached 0 Attached 0 maximum units per building 0 Commercial/Industrial/Institutional Building Area (gross floor space): total square feet Indicate area of specific uses (in square feet): Office N/A Manufacturing N/A Retail Other Industrial 10 acres (wastewater lagoons) N/A 2 acres (piping trenches) Warehouse N/A Institutional N/A Light Industrial N/A Agricultural 2 acres (outside of lagoon embankments) Other Commercial (specify) Building height If over 2 stories, compare to heights of nearby buildings 8. Permits and approvals required. List all known local, state and federal permits, approvals and financial assistance for the project. Include modifications of any existing permits, governmental review of plans, and all direct and indirect forms of public financial assistance including bond guarantees, Tax Increment Financing and infrastructure. Unit of Government Type of Application Status MPCA NPDES/State Disposal System Permit Draft permit currently on public notice MPCA Construction Permit Submitted MPCA Stormwater Permit To be submitted DeWald Township Utilities Permit Completed Buffalo Ridge Regional Rail Utilities Permit Submitted Authority Nobles County Conditional Use Permit To be submitted Little Rock-Kanaranzi Watershed Title Permit To be submitted Board DNR Temporary Water Appropriation Permit To be submitted U.S. Corps of Engineers 404 Permit To be submitted 9. Land use. Describe current and recent past land use and development on the site and on adjacent lands. Discuss project compatibility with adjacent and nearby land uses. Indicate whether any potential conflicts involve environmental matters. Identify any potential environmental hazards due to past site uses, such as soil contamination or abandoned storage tanks, or proximity to nearby hazardous liquid or gas pipelines. The site of the existing WWTF is located west and south of the City. All adjacent property is agricultural and currently being used for row crop production. A total of ten acres of cropland would be used for the new pond and related structures. The proposed new primary lagoon cell would be adjacent to two existing primary stabilization ponds and one secondary pond. Typically, spring is the time of the year when odors can be a problem near stabilization pond systems. As ice melts, ponds can release unpleasant odors, typically for a period of two to three weeks. To date, odors from the ponds have not been a problem for residents in the City. Expansion of the WWTF is not Rushmore, Minnesota 4 Worksheet

6 expected to cause any new odor impacts in the community. The site of the proposed new stabilization pond has been used for agricultural purposes only. There are no known potential environmental hazards due to past site uses. 10. Cover Types. Estimate the acreage of the site with each of the following cover types before and after development: Before After Before After Types 1-8 wetlands 0 0 Lawn/landscaping 0 0 Wooded/forest 0 0 Impervious Surfaces 0 0 Brush/grassland 0 0 Other (describe) 0 10 Cropland 12 2 (treatment pond) TOTAL Fish, Wildlife, and Ecologically Sensitive Resources. a. Identify fish and wildlife resources and habitats on or near the site and describe how they would be affected by the project. Describe any measures to be taken to minimize or avoid impacts. The area near the existing WWTF is nearly all under cultivation. As a result of the intensive agricultural practices in the area, wildlife habitat is limited. The proposed project will not substantially change that condition. The Topeka Shiner is a federally listed endangered fish species found within the Big Sioux/Rock River Watershed in Minnesota. In 2004, the MPCA staff conducted a fish survey at two sites in the vicinity of the City. One sampling site was located in a tributary of the West Branch of Little Rock Creek. The other site was located in the Little Rock River. The Topeka Shiner was not found in either of these locations. However, populations of Topeka Shiners have been found by DNR staff, approximately nine miles downstream of the City s WWTF. Currently, untreated and partially treated wastewater is being discharged to an unnamed tributary of Little Rock Creek in a somewhat unpredictable manner. Whenever I/I is high and the existing system cannot handle the flows, bypasses of untreated wastewater can occur. Once the expansion is completed, all wastewater will be captured, transported to the WWTF, properly treated and released in a controlled and predictable manner. Staff from the DNR and the U.S. Fish and Wildlife Service have been contacted about the proposed project and are aware of the proximity of Topeka Shiner populations. Neither agency has determined that Topeka Shiner populations will be impacted by this project and no objections to the project have been raised. b. Are any state (endangered or threatened) species, rare plant communities or other sensitive ecological resources such as native prairie habitat, colonial waterbird nesting colonies or regionally rare plant communities on or near the site? Yes No If yes, describe the resource and how it would be affected by the project. Indicate if a site survey of the resources has been conducted and describe the results. If the DNR Natural Heritage and Nongame Research program has been contacted give the correspondence reference number. ERDB Describe measures to minimize or avoid adverse impacts. The DNR Natural Heritage Database was queried regarding the possible presence of rare, special concern, or endangered species in the project area. The DNR identified two known occurrences of rare species in the vicinity of the project. The two rare features identified in the project area were a Mesic Prairie remnant and a threatened plant species, Sullivant s Milkweed (Asclepias sullivantii). Rushmore, Minnesota 5 Worksheet

7 However, based on the nature and location of the WWTF expansion, DNR staff has determined those species would not be affected (Figure 5). See Item 11a. The City s WWTF is located upstream of an area in the Little Rock River Complex that has been identified as critical habitat for the Topeka Shiner, an endangered fish species (Figure 6). The Topeka shiner is Minnesota s only federally endangered fish species, listed in In Minnesota, this fish has been listed as a species of concern. The U.S. Fish and Wildlife Service has conducted surveys of the Topeka Shiner populations in the Little Rock River Complex. The Topeka Shiner is found only in the Big Sioux and Rock River Watersheds in Minnesota. There are several factors likely affecting populations of the Topeka shiner in Minnesota (Kuitunen 2001). Topeka shiners live in prairie streams. Most of these streams have been severely degraded in the Midwest by agricultural practices (Waters 1995). Channelization, dam construction, removal of riparian vegetation, and increased runoff of water and sediment from farm fields have all contributed to its endangered status. When DNR conducted field surveys of the Topeka shiner habitat, they found that the shiners were more abundant in stable stream channels than in unstable, degraded stream channels. Most individuals were found in clearer, vegetated backwaters. Stable, nondegraded stream channels, as well as good connectivity between upstream and downstream stream reaches are all important factors in determining the long-term health of shiner populations (Kuitunen 2001). DNR fish sampling surveys were completed in Nobles County in the 1990s. DNR staff has found Topeka Shiners in a stretch of the Little Rock River, approximately nine miles downstream of the proposed discharge for the City s WWTF. MPCA staff has collected Topeka Shiners at 5 of 25 sampled locations within the Missouri River Basin, however none have been found in the vicinity of the City s WWTF. Staff of the U.S. Fish and Wildlife Service and the DNR staff are aware of the proposed project and have not raised any concerns about potential impacts to shiner populations in the area (Figure 7). 12. Physical Impacts on Water Resources. Will the project involve the physical or hydrologic alteration (dredging, filling, stream diversion, outfall structure, diking, and impoundment) of any surface waters such as a lake, pond, wetland, stream or drainage ditch? Yes No If yes, identify water resource affected. Describe alternatives considered and proposed mitigation measures to minimize impacts. Give the DNR Protected Waters Inventory (PWI) number(s) if the water resources affected are on the PWI. There are no DNR Protected Waters within the project area. See Figure Water Use. Will the project involve installation or abandonment of any water wells, connection to or changes in any public water supply or appropriation of any ground or surface water (including dewatering)? Yes No If yes, as applicable, give location and purpose of any new wells; public supply affected, changes to be made, and water quantities to be used; the source, duration, quantity and purpose of any appropriations; and unique well numbers and DNR appropriation permit numbers, if known. Identify any existing and new wells on the site map. If there are no wells known on site, explain methodology used to determine. The new primary stabilization pond would be required to pass a water balance test before it can be used for the first time. This ensures that the new pond will not leak at a level that exceeds 500 gallons per acre per day, the current state standard. To conduct this test, the pond must be filled with water to a depth of two feet. This would require 8.9 million gallons of water. The proposer will have to obtain a Temporary Water Appropriations Permit from the DNR for this test. The permit would allow the proposer to extract Rushmore, Minnesota 6 Worksheet

8 water from a temporary well, stream, or other source in the area. Once the test is completed, water withdrawal would cease. 14. Water-related land use management districts. Does any part of the project involve a shoreland zoning district, a delineated 100-year flood plain, or a state or federally designated wild or scenic river land use district? Yes No If yes, identify the district and discuss project compatibility with district land use restrictions. 15. Water Surface Use. Will the project change the number or type of watercraft on any water body? Yes No If yes, indicate the current and projected watercraft usage and discuss any potential overcrowding or conflicts with other uses. 16. Erosion and Sedimentation. Give the acreage to be graded or excavated and the cubic yards of soil to be moved: 10 acres; cubic yards. Describe any steep slopes or highly erodible soils and identify them on the site map. Describe any erosion and sedimentation control measures to be used during and after project construction. There are no steep slopes or highly erodible soils within the project area. Before construction activities can begin, the proposer would have to apply for and obtain a General NPDES Permit for Construction Activity from the MPCA. The General Construction Stormwater Permit (Permit) is required when construction disturbs one or more acres of soil. This Permit outlines specific requirements for managing surface water runoff during the construction phase of the project. The Permit requires that Best Management Practices (BMPs) be implemented to prevent soil erosion and the movement of sediment offsite. The proposer would implement the preventive measures outlined in the Temporary and Permanent Erosion and Sediment Control Plans developed for this site (Figure 9). The proposer would utilize silt fences, bale or rock check dams, vegetated buffer strips, grassed swales, and temporary storm ponds during construction to prevent impacts to surface waters. Once all construction work is completed, the entire disturbed area outside of the pond s dike slopes would be permanently seeded with grasses. This would prevent erosion and sedimentation, while encouraging infiltration of rainwater and snowmelt on the site. The force main piping would be installed via directional boring and traditional trenching methods. The width of the sewer pipe trench would be kept to a minimum to reduce the amount of disturbed soil. The amount of sewer trench open at any one time would also be limited. Silt fences would be constructed as necessary to keep soil on site and out of streets. The sewer pipe trench would be capped during work stoppages to prevent sediment from washing into the sewer system. Once the new sewer pipe had been laid, road surfaces would be replaced as soon as practical. Precautionary activities such as the implementation of BMPs, final grading and reseeded of disturbed areas after construction, and the resurfacing of streets in a timely manner should prevent erosion and sedimentation, and their potential impacts to surface water. 17. Water Quality Surface-water Runoff. a. Compare the quantity and quality of site runoff before and after the project. Describe permanent controls to manage or treat runoff. Describe any storm-water pollution prevention plans. Rushmore, Minnesota 7 Worksheet

9 The 12-acre plot of land that would be used for constructing the new stabilization pond has been used for row crop agriculture and is presently maintained in a temporary cover crop to reduce soil erosion. Some surface-water runoff and soil erosion is likely occurring at the present time, though it has never been quantified. Once the new pond is constructed and permanent vegetation is established around it, the potential for soil erosion is quite small. The new pond would serve as a catchment for most of the precipitation falling on the site, allowing for treated water to be released in a controlled manner to an unnamed tributary of Little Rock Creek. Vegetation surrounding the pond would encourage infiltration of rainfall and snowmelt. Fertilizers and pesticides currently being used on the agricultural land will no longer be needed, reducing potential impacts to surface waters. b. Identify routes and receiving water bodies for runoff from the site; include major downstream water bodies as well as the immediate receiving waters. Estimate impact runoff on the quality of receiving waters. Runoff leaving the site would move toward an unnamed creek, which would eventually reach a tributary to the Little Rock Creek. With the appropriate use of BMPs during construction and the establishment of permanent vegetation after construction, impacts to surface water are expected to be minimal. After construction is completed and the site is stabilized, there is a possibility that the quantity of the runoff leaving the site would decrease and that its quality would improve to some degree. 18. Water Quality Wastewater. a. Describe sources, composition and quantities of all sanitary, municipal and industrial wastewater produced or treated at the site. Plant Capacity Existing Operations Existing Permitted Capacity Proposed* AWWF (gpd) 114,600 gpd 47,270 gpd 99,000 gpd * Takes into account infiltration and inflow reduction from manhole rehabilitation. Influent Composition The proposed WWTF expansion would treat wastewater from domestic and commercial sources. The composition of the influent wastewater would remain unchanged after the expansion. The composition of raw wastewater entering the WWTF has the following characteristics: Influent Biochemical Oxygen Demand (CBOD5) 203 milligrams per liter (mg/l) Total Suspended Solids (TSS) 97 mg/l ph 7-9 The WWTF would be operated in a controlled discharge mode with discharges in the spring and fall (April 1 to June 15 and September 15 to December 15). The treated effluent and pond perimeter drain tile would continue to be discharged into a buried drain tile, which eventually empties into an unnamed tributary to the Little Rock Creek, approximately one-half mile west of the WWTF (Figure 4). Table 1 summarizes the existing average and maximum discharges for the WWTF and the lift station bypass location. The proposed NPDES Permit for the expanded WWTF would authorize an increase Rushmore, Minnesota 8 Worksheet

10 in the peak daily and average daily discharge rates by a factor of approximately 2. At the same time, the proposed project would eliminate the discharges from the lift station bypass location. b. Describe waste treatment methods or pollution prevention efforts and give estimates of composition after treatment. Identify receiving waters, including major downstream water bodies, and estimate the discharge impact on the quality of receiving waters. If the project involves on-site sewage systems, discuss the suitability of site conditions for such systems. The existing WWTF, constructed in 1971, consists of two primary stabilization ponds and one secondary pond. The WWTF s NPDES Permit allows for an influent treatment capacity of 47,270 gpd. At present, the WWTF is regularly exceeding the conditions of the NPDES Permit. Wet weather influent flows often exceed 100,000 gpd. As a result of persistent permit violations, including the bypassing of untreated and partially treated wastewater, the MPCA has issued a compliance schedule that the City must meet to bring the WWTF into full compliance with its permit. This has led to a redesign and expansion of the existing WWTF. Proposed Treatment Process Raw wastewater collected within Rushmore would be pumped to the WWTF where it would enter the new and existing primary treatment ponds. The new primary treatment pond was designed larger than would otherwise be required due to the large amounts of I/I in the system. In the primary treatment ponds, natural physical and chemical processes would break down wastes. These processes would be performed by sunlight, naturally-occurring bacteria, micro-organisms, plants and algae. Within the primary ponds, the majority of solids would settle to the bottom of the ponds and bacteria would begin to break down oxygen demanding substances. Sunlight (ultraviolet radiation) would provide a natural disinfection process, destroying many pathogens present in the wastewater. The ponds would be designed to be relatively shallow, at six feet deep. Shallow depths would allow sunlight to penetrate to the bottom and encourage the proper amounts of aeration, and mixing. Shallow depths would also prevent anaerobic (septic) conditions, and the odors associated with them. The bottom two feet of the pond is for biosolids storage and treatment. The pond dike heights and freeboard are designed in accordance with MPCA guidelines to ensure the safety of the dikes. The new pond would be constructed with a clay liner. The liner would be constructed to maintain or exceed the required separation distance of four feet above ground-water level. Ponds would be constructed so that they do not leak at a rate which exceeds 500 gallons per acre per day. After primary treatment, wastewater would move to the secondary treatment ponds where additional treatment would occur. During secondary treatment, oxygen demanding substances and solids would be significantly reduced. Bacteria and sunlight would again be the active agents in the treatment and disinfection of wastewater. The ponds are designed to provide 180 days of wastewater storage, and adequate time for waste treatment. Approximately every 180 days, wastewater would be discharged from the ponds to the unnamed tributary to the Little Rock Creek. Prior to discharge, effluent samples would be collected and analyzed to ensure compliance with the NPDES Permit effluent limits. The treated wastewater would be discharged in a way that would be coordinated with periods in the spring and fall, when the receiving waters are typically at a higher stage and are less sensitive to the influence of discharges. Proposed Effluent Limits Rushmore, Minnesota 9 Worksheet

11 The following draft effluent limitations have been proposed for the expanded pond system: AWW Flow CBOD* TSS* Fecal coliform* ph Domestic 99,000 gpd 25 mg/l 45 mg/l 200 organisms/100ml Range of wastewater (April 1 - Oct. 31) 6.0 to 9.0 from the City *Monthly average ml = milliliter These limits are designed to protect the beneficial uses of the unnamed tributary of Little Rock Creek, including fisheries, wildlife, recreation, agricultural uses and other designated uses. Table 1 summarizes the existing discharge concentrations for CBOD, TSS, fecal coliform and phosphorus from the WWTF. The MPCA anticipates that the proposed project will significantly reduce the discharge concentrations and loadings of these four pollutants and that the proposed effluent limits will consistently be met. Based on data from similar WWTFs, the MPCA staff also expects that the proposed project will significantly reduce the discharge concentrations and mass loadings of ammonia to the tributary of Little Rock Creek. c. If wastes will be discharged into a publicly owned treatment facility, identify the facility, describe any pretreatment provisions and discuss the facility s ability to handle the volume and composition of wastes, identifying any improvements necessary. The proposed project is the publicly owned WWTF. d. If the project requires disposal of liquid animal manure, describe disposal technique and location and discuss capacity to handle the volume and composition of manure. Identify any improvements necessary. Describe any required setbacks for land disposal systems. N/A. 19. Geologic hazards and soil conditions. a. Approximate depth (in feet) to Ground water: 7 feet minimum; 8 feet average. Bedrock: >26 feet minimum; >26 feet average. Describe any of the following geologic site hazards to ground water and also identify them on the site map: sinkholes, shallow limestone formations or karst conditions. Describe measures to avoid or minimize environmental problems due to any of these hazards. There are no known sinkholes, shallow limestone formations, or Karst conditions. b. Describe the soils on the site, giving SCS classifications, if known. Discuss soil granularity and potential for ground-water contamination from wastes or chemicals spread or spilled onto the soils. Discuss any mitigation measures to prevent such contamination. Soils are generally of the Everly and Sac series, consisting of well drained soils in glacial till uplands. These are soils formed in glacial till, with a loessial influence on the surface in some places. Soil borings performed at the proposed treatment site generally found clay till soils encountered about four feet below existing grade. The new lagoon cell would be constructed to meet the State seepage standard of 500 gallons per acre per day to limit the potential for ground-water contamination. Rushmore, Minnesota 10 Worksheet

12 20. Solid Wastes, Hazardous Wastes, Storage Tanks. a. Describe types, amounts and compositions of solid or hazardous wastes, including solid animal manure, sludge and ash, produced during construction and operation. Identify method and location of disposal. For projects generating municipal solid waste, indicate if there is a source separation plan; describe how the project will be modified for recycling. If hazardous waste is generated, indicate if there is a hazardous waste minimization plan and routine hazardous waste reduction assessments. None identified. b. Identify any toxic or hazardous materials to be used or present at the site and identify measures to be used to prevent them from contaminating ground water. If the use of toxic or hazardous materials will lead to a regulated waste, discharge or emission, discuss any alternatives considered to minimize or eliminate the waste, discharge or emission. None identified. c. Indicate the number, location, size and use of any above or below ground tanks to store petroleum products or other materials, except water. Describe any emergency response containment plans. None. 21. Traffic. Parking spaces added: N/A Existing spaces (if project involvesexpansion): N/A Estimated total average daily traffic generated: N/A Estimated maximum peak hour traffic generated (if known) and its timing: N/A Provide an estimate of the impact on traffic congestion affected roads and describe any traffic improvements necessary. If the project is within the Twin Cities metropolitan area, discuss its impact on the regional transportation system. No parking spaces would be added as a result of the proposed expansion. The major street that will be impacted by force main construction activities would be West Avenue. This is not a major road and lies on the outskirts of town. Much of the work in this area will be performed using directional boring techniques, which should minimize disruptions to residents and traffic. Residents along this route will also have access to the alley behind their homes, reducing the potential for inconvenience during construction. The contractor will be required to maintain access as much as practical. 22. Vehicle-related Air Emissions. Estimate the effect of the project s traffic generation on air quality, including carbon monoxide levels. Discuss the effect of traffic improvements or other mitigation measures on air quality impacts. Note: If the project involves 500 or more parking spaces, consult EAW Guidelines about whether a detailed air quality analysis is needed. It is estimated that City staff currently make approximately one trip per week to the WWTF for routine operation and maintenance activities. This would not change as a result of the expansion. 23. Stationary Source Air Emissions. Describe the type, sources, quantities and compositions of any emissions from stationary sources of air emissions such as boilers, exhaust stacks or fugitive dust sources. Include any hazardous air pollutants (consult EAW Guidelines for a listing), any greenhouse gases (such as carbon dioxide, methane, and nitrous oxides), and ozone-depleting chemicals (chlorofluorocarbons, Rushmore, Minnesota 11 Worksheet

13 hydrofluorocarbons, perfluorocarbons or sulfur hexafluoride). Also describe any proposed pollution prevention techniques and proposed air pollution control devices. Describe the impacts on air quality. None identified. 24. Odors, noise and dust. Will the project generate odors, noise or dust during construction or during operation? Yes No If yes, describe sources, characteristics, duration, quantities or intensity and any proposed measures to mitigate adverse impacts. Also identify locations of nearby sensitive receptors and estimate impacts on them. Discuss potential impacts on human health or quality of life. (Note: fugitive dust generated by operations may be discussed at item 23 instead of here.) Odor There have been no known odor complaints related to the existing WWTF. The expansion is not expected to cause or create new odor impacts in the community. Dust Dust would be generated when the new pond, piping and other infrastructure is constructed. Dust within the City will be controlled by water trucks when necessary. Upon completion of construction activities, all disturbed areas near the sewer trenches would be reseeded. Streets would be resurfaced as needed. Dust generated by construction equipment at the WWTF site would also be controlled with water applications, should it become a nuisance. Areas around the new pond would also be reseeded soon after construction is terminated. This will reduce the potential for dust to become airborne and cause a nuisance condition. Noise Noise from construction equipment would be similar to that of agricultural machinery currently in use in the area. Noise impacts within the City and at the WWTF site would be temporary in nature. Equipment would have appropriate mufflers and will only be operated during daylight hours in order to reduce impacts to residents. 25. Nearby resources. Are any of the following resources on or in proximity to the site? a. Archaeological, historical, or architectural resources? Yes No b. Prime or unique farmlands or land within an agricultural preserve? Yes No c. Designated parks, recreation areas, or trails? Yes No d. Scenic views and vistas? Yes No e. Other unique resources? Yes No If yes, describe the resource and identify any project-related impacts on the resources. Describe any measures to minimize or avoid adverse impacts. The MHS has concurred that no significant historical or archaeological sites are known to occur within the project area (Figure 10). Rushmore, Minnesota 12 Worksheet

14 26. Visual impacts. Will the project create adverse visual impacts during construction or operation? Such as glare from intense lights, lights visible in wilderness areas and large visible plumes from cooling towers or exhaust stacks? Yes No If yes, explain. 27. Compatibility with plans and land use regulations. Is the project subject to an adopted local comprehensive plan, land use plan or regulation, or other applicable land use, water, or resource management plan of a local, regional, state or federal agency? Yes No If yes, describe the plan, discuss its compatibility with the project and explain how any conflicts will be resolved. If no, explain. 28. Impact on infrastructure and public services. Will new or expanded utilities, roads, other infrastructure or public services be required to serve the project? Yes No If yes, describe the new or additional infrastructure or services needed. (Note: any infrastructure that is a connected action with respect to the project must be assessed in the EAW; see EAW Guidelines for details.) All infrastructure improvements needed to serve the project are included in the project. 29. Cumulative impacts. Minn. R , subp. 7, item B requires that the RGU consider the cumulative potential effects of related or anticipated future projects when determining the need for an environmental impact statement. Identify any past, present or reasonably foreseeable future projects that may interact with the project described in this EAW in such a way as to cause cumulative impacts. Describe the nature of the cumulative impacts and summarize any other available information relevant to determining whether there is potential for significant environmental effects due to cumulative impacts (or discuss each cumulative impact under appropriate item(s) elsewhere on this form). The proposed improvements are intended to primarily serve the existing population, with only a small allotment of capacity for future growth. The project involves expansion of the WWTF and related infrastructure, with no planned expansion of the collection system. No effects are anticipated except those addressed in this review. 30. Other Potential Environmental Impacts. If the project may cause any adverse environmental impacts not addressed by items 1 to 28, identify and discuss them here, along with any proposed mitigation. None. 31. Summary of issues. List any impacts and issues identified above that may require further investigation before the project is begun. Discuss any alternatives or mitigative measures that have been or may be considered for these impacts and issues, including those that have been or may be ordered as permit conditions. When considering how the WWTF would be redesigned to meet water quality standards and comply with the NPDES Permit, the City first looked at performing a major sewer rehabilitation project in order to reduce influent flows to the WWTF. It was determined that even with a large reduction in I/I, an expansion of the WWTF would still be necessary. Because the community had a functioning WWTF, alternative treatment options were not considered. A no-action alternative was not considered either, since the WWTF had to be brought into compliance with its NPDES Permit. Rushmore, Minnesota 13 Worksheet

15 RGU CERTIFICATION. I hereby certify that: The information contained in this document is accurate and complete to the best of my knowledge. The EAW describes the complete project; there are no other projects, stages or components other than those described in this document, which are related to the project as connected actions or phased actions, as defined at Minn. R , subps. 9b and 60, respectively. Copies of this EAW are being sent to the entire EQB distribution list. Name and Title of Signer: Beth G. Lockwood, Supervisor, Environmental Review Unit Environmental Review and Operations Section Regional Division Date: The format of the Worksheet was prepared by the staff of the Environmental Quality Board at Minnesota Planning. For additional information, worksheets or for EAW Guidelines, contact: Environmental Quality Board, 658 Cedar St., St. Paul, MN 55155, , or at their Web site Rushmore, Minnesota 14 Worksheet