If you have any questions on the EAW, please contact Denise Leezer of my staff at (651)

Transcription

1 May 11, 2001 TO INTERESTED PARTIES: RE: Benton Utilities LLC Wastewater Treatment Facility Enclosed is the Worksheet (EAW) for the proposed Benton Utilities LLC Wastewater Treatment Facility, Benton 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 May 14, 2001, issue. 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 nine-member 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 Denise Leezer of my staff at (651) Sincerely, Beth G. Lockwood District Planning Supervisor Operations and Planning Sections North, South, and Metro Districts BGL:gs 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 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: 2. Proposer: Benton Utilities LLC 3. RGU: Minnesota Pollution Control Agency Contact Person Lee Hanson Contact Person Denise M. Leezer and Title Owner and Title Project Manager Address th Street Northeast Address 520 Lafayette Road North Rice, MN St. Paul, MN Phone (320) Phone (651) Fax None 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: 5. Project Location: County Benton County City/Township Watab Township NE 1/4 NE 1/4 Section 23 Township T37N Range R31W Tables, Figures, and Appendices attached to the EAW: Figure 1: County map showing the general location of the project; Figure 2: United States Geological Survey 7.5 minute, 1:24,000 scale map indicating project boundaries; Figure 3: Site plan showing all significant project and natural features; Figure 4: Aerial Photo; Figure 5: Soils Map; Figure 6: Wastewater Schematic; Figure 7: Future Project Phase Map; Figure 8: Letter from Minnesota Department of Natural Resources (DNR); and Figure 9: Letter from Minnesota Historical Society. TDD (for hearing and speech impaired only): (651) Printed on recycled paper containing 100% fibers from paper recycled by consumers

3 6. Description: a. Provide a project summary of 50 words or less to be published in the EQB Monitor. Benton Utilities LLC proposes to construct a wastewater treatment system to serve the existing Golf Haven residential development, the proposed Conservancy residential development and the eventual development of 191 acres of adjacent property. The wastewater system consists of septic tanks, recirculating gravel filters, single pass sand filters and ultraviolet disinfection. The treated wastewater will be discharged to a partially ditched, palustrine (inland) emergent wetland, which is seasonally flooded. The discharge will flow from the wetland to an unnamed intermittent creek, which is a tributary to Little Rock Creek, then to the Mississippi River. 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. Benton Utilities LLC proposes to construct a wastewater treatment system to serve the existing Golf Haven residential development, the proposed Conservancy residential development, and the eventual development of 191 acres of adjacent property. The wastewater system consists of septic tanks, recirculating gravel filters, single pass sand filters and ultraviolet disinfection. The treated wastewater will be discharged to a partially ditched, palustrine (inland) emergent wetland, which is seasonally flooded. The discharge will flow from the wetland to an unnamed intermittent creek, which is a tributary to Little Rock Creek, then to the Mississippi River. System Description (General) The treatment process includes six identical treatment systems running in parallel. Phase I of construction will consist of two of these treatment trains. As the need arises, additional dual-train systems will be added to the treatment system. Each phase will have the capability to treat 50,000 gallons per day. This design approach allows redundancy between the treatment units. The total design capacity, once all phases are complete, will be 150,000 gallons per day (gpd). One set of treatment trains for the proposed wastewater treatment system is depicted in a wastewater schematic in Figure 6. Collection systems for each development will be designed to discharge to a raw sewage lift station that will split the flow evenly between parallel treatment trains. The treatment process begins with a series of septic tanks. The flow from the septic tanks discharges to a filter tank and then is sent through a recirculation tank that doses a vertical flow wetland (with Forced Bed Aeration TM ). The vertical flow wetland is in effect a recirculating gravel filter with enhancements. The Vertical Flow Wetland treatment systems are designed to provide treatment of the wastewater. A single pass sand filter will polish the treated effluent prior to ultraviolet (UV) disinfection. The treated and disinfected water will then be discharged to the receiving water consisting of a wetland complex located in the Conservancy development area. Flow will be monitored and will be sampled according to the National Pollutant Discharge Elimination System (NPDES) Permit to be issued by the MPCA. Lift Station A 12-foot diameter pre-cast concrete manhole will be located at the terminus of the gravity sewer system. The manhole will serve as the wet well for the duplex submersible raw sewage lift station. The lift station is sized so that four additional pumps, serving phases 2 and 3, may be added as the need arises. Benton County, Minnesota 2 Worksheet

4 The raw sewage pumps will be capable of passing a three-inch solid and are designed to pump the peak hourly wet weather flow for each phase (125,000 gpd, or approximately 90 gallons per minute) with one pump out of service. Pumps will operate on-demand using float switches, and will alternate lead-lag status after each pump cycle. An external alarm light and horn will be activated in the event of a high water level alarm. In addition, an automatic dialer, that monitors all of the pumps in the system, will alert the wastewater treatment operator of a pump malfunction. Each pump has its own dedicated force main, which discharges into a series of septic tanks (three per pump). In this way, the alternating feature of the pump controls will be used to split the raw sewage flow. The pump control panel is designed for operation from a portable generator in the event of an extended power outage. Septic Tanks Three precast concrete septic tanks in series will be used in each treatment train to provide for primary treatment of the wastewater, after flow splitting at the lift station. Each septic tank will be 10,000 gallons. The first septic tank in each train will be single compartment, while the remaining two tanks will be two compartments. This meets the requirements of Minn. R , subp. 2.0, and , subp. 3C(2). Filter Tanks A 10,000-gallon, single compartment, pre-cast concrete tank will be used as a filter tank. Return flows, from the vertical flow wetlands, enter these tanks and mix with the septic tank effluent. Twelve commercial septic tank filters in each tank trap any biosolids sloughing off the vertical flow wetlands and any solids that may escape from the septic tanks. The nitrified wastewater, oxygenated by Forced Bed Aeration TM, will mix with the septic tank effluent (a carbon source) under anoxic conditions, allowing denitrification of the wastewater. Recirculation Pumps (Vertical Flow Wetland) The re-circulation tank is a 10,000-gallon pre-cast concrete tank for each treatment train. Each tank will contain three pumps for re-circulating the flow through each vertical flow wetland. The proposed recirculation flow is five times the forward flow, or 125,000 gpd per wetland cell. Three re-circulation pumps dose each vertical flow wetland cell. Each dosing pump is hard-piped into one of three dosing zones. Each dosing zone consists of eight 2-inch schedule 40 PVC perforated distribution laterals. The perforation diameter, spacing, and lateral size have been designed so that there is less than 10 percent difference in the discharge rate between the orifices. Each perforated distribution lateral has a flushing valve at the terminal end. In order to uniformly pressure dose the wetland, the application rate must be higher than the recycle flow. The re-circulation pumps operate from timer switches, which can be adjusted by the operator to set the dosing interval and frequency. The pumps alternate among the three after each pump cycle. Pumps can be operated from a portable generator in the event of an extended power outage. The re-circulation pump tanks are interconnected so that one of the vertical flow wetlands can be taken out of service if necessary. Vertical Flow Wetland (Attached Growth Filter) For wastewater treatment, the Benton Utility LLC is proposing a vertical flow wetland (re-circulating gravel filter) system. Each treatment cell will be 8,400 square feet in size. The vertical flow wetlands consist of a filter bay, constructed below grade in a cell lined with 30-mil PVC. Benton County, Minnesota 3 Worksheet

5 The treatment media is a 30-inch layer of 1/2-inch minus gravel, underlain by a 12-inch drainage layer of 2 to 4-inch drainfield rock. The treatment bed will be insulated with a 6-inch mulch layer to provide odor control, prevent freezing, and support wetland plants that aid in the treatment process. The mulch material will be peat. On average, wastewater will be re-circulated approximately five times through the vertical flow wetland. The re-circulation flow for each filter is approximately 125,000 gpd. The vertical flow wetlands each have a footprint area of 8,400 square feet. The resulting hydraulic loading of 3.0 gpd (forward flow) per square foot is within design guidelines (3.0 to 5.0 gpd) published in the U.S. Environmental Protection Agency s (EPA) Onsite Wastewater Treatment and Disposal Systems Design Manual. With septic tank pretreatment, the Carbonaceous Biochemical Oxygen Demand (CBOD) load on the system is approximately 188 pounds per day (assuming a CBOD reduction of 40 percent in the septic tanks). The organic loading on the vertical flow wetland would be about pounds per square foot per day. This is within the design guidelines for re-circulating gravel filters published in Wastewater Engineering - Treatment, Disposal, Reuse, Metcalf and Eddy, Third Edition. The insulating mulch layer covering the wetland may limit atmospheric diffusion of oxygen into the system. To maintain an aerobic environment within the filter, the Forced Bed Aeration TM system is proposed. A regenerative blower will periodically force air up through each wetland bed. Dosing Pumps (Sand Filter) A 10,000-gallon pre-cast concrete dosing tank will follow each re-circulation tank. Each of these tanks will have three pumps that pressure dose one of the single pass sand filters. Pre-treated effluent will flow from the re-circulation tanks, by gravity, into the dosing tanks. Pressure dosing of the sand filter will occur on a demand basis. Each sand filter dosing pump is hard-piped into one of three dosing zones. Each dosing zone consists of eight 2-inch Schedule 40 PVC perforated distribution laterals. The perforation diameter, spacing, and lateral size have been designed so that there is less than 10 percent difference in the discharge rate along each lateral. Each perforated distribution lateral has a flushing valve at the terminal end. The sand filter dosing pumps operate on a demand basis. The dosing pumps alternate among the three after each pump cycle. The sand filter dosing pumps have been designed so that they are capable of pumping the peak hourly wet weather flow. The dosing pumps can be operated from a portable generator in the event of an extended power outage. The dosing pump tanks are interconnected so that one of the sand filters can be taken out of service if necessary. Single Pass Sand Filter A single pass sand filter will be used for effluent polishing prior to UV disinfection. The sand filters are each dosed by a separate dosing tank. Each sand filter is pressure dosed by three alternating pumps. Each 10,080 square foot sand filter will be loaded at approximately 2.5 gallons per square foot (at design flow). This is about twice the loading used for septic tank effluent. This approach allows downsizing of single pass sand filters when used strictly for effluent polishing. Ultra Violet Disinfection System Before being discharged, the treated and polished effluent will flow through an UV disinfection unit. The UV unit is designed to provide disinfection at the peak hourly wet weather flow. This will kill most of the remaining fecal coliform and other disease causing organisms before surface discharge. Each phase will have a separate UV system designed to treat the peak hourly wet weather flow of 125,000 gpd per phase. Benton County, Minnesota 4 Worksheet

6 Flow Metering After passing through the UV unit, effluent will flow through a 0.5-foot H flume. Flow will be recorded and totaled by a bubbler-style flow meter. Following the flow meter, the treated and disinfected effluent will gravity flow to the surface discharge point. 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 wastewater services to the existing Golf Haven residential development, the proposed Conservancy residential development and the eventual development of 191 acres adjacent to the property. 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. The wastewater treatment system will be developed in three phases. Each phase includes three 10,000- gallon septic tanks, two re-circulating vertical flow wetlands, two sand filters and ultraviolet disinfection. As the flow from the contributing service area dictates, two equally sized additions will be constructed. This EAW addresses all three phases of the wastewater treatment system. The Benton Utilities service area will develop in phases (See figure 7 for development phasing). The existing 25-lot Golf Haven development and the first phase of The Conservancy development will be serviced by the first phase (50,000 gpd) of the wastewater treatment system. As additional development occurs in the service area and the wastewater system reached 80 percent of its capacity, the second phase of the treatment system will be built. Subsequent stages of development in the Benton Utilities service area will complete an Environmental Assessment Worksheet, as appropriate, prior to beginning construction. An EAW was prepared by Benton County for the proposed Conservancy residential development and was published in the EQB Monitor in April Comments were received during the public notice period and the EAW was placed on hold. No declarations regarding the potential for significant environmental effect were made. Subsequently, the scope of the EAW has been expanded and a new EAW will be placed on public notice in the EQB Monitor. e. Is this project a subsequent stage of an earlier project? Yes No If yes, briefly describe the past development, timeline and any past environmental review. The wastewater treatment system will incorporate the wastewater from the Golf Haven development. No environmental review was required for the Golf Haven development. Benton County, Minnesota 5 Worksheet

7 7. Project Magnitude Data Total Project Area (acres) 7.7 acres or Length (miles) Number of Residential Units: Unattached Attached maximum units per building Commercial/Industrial/Institutional Building Area (gross floor space): total square feet Indicate area of specific uses (in square feet): Office Manufacturing Retail Other Industrial Warehouse Institutional Light Industrial Agricultural Other Commercial (specify) Building height 10 feet If over 2 stories, compare to heights of nearby buildings The wastewater treatment system will be located on 7.7 acres of the proposed Conservancy development. With the exception of a small 10 feet by 10 feet control building, areas disturbed by the wastewater system will be replanted in native prairie and wetland vegetation. The service area for Benton Utilities consists of the existing 25-home Golf Haven development, the proposed 400-acre Conservancy residential development and the eventual development of 190 acres of adjacent land. The first phase of the proposed Conservancy development will be 160 acres. The Conservancy is being rezoned from A-2 Agricultural to R-2 Medium Density Residential. The 190-acre remainder of the service area is adjacent to Highway 10 and is zoned heavy industrial 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 Storm Water Pending MPCA NPDES Pending MPCA Sanitary Sewer District To be submitted DNR Permit for work in the bed of public water 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 proposed wastewater treatment system will be located on 7.7 acres of the proposed Conservancy development area. The land was farmed over 30 years ago. The land use is now considered open space. No known environmental hazards exist from former and current use of the land. Benton County, Minnesota 6 Worksheet

8 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 Lawn/landscaping * Wooded/forest Impervious Surfaces Brush/grassland 7.7acres 7.58 acres Other (describe) Cropland TOTAL * Landscaping will be re-planted in grasses and wetland plants and are not considered a conversion from brush/grassland cover type. 11. 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. Wildlife frequenting the open land and the adjacent wooded areas include deer, raccoon, fox, skunk, rabbits, moles, gophers, and mice. Birds such as waterfowl, songbirds, and birds of prey frequent the site. Reptiles such as snakes, frogs, toads, and turtles are present. Other species indigenous to the area also frequent the site. Wildlife displaced during construction will likely return after construction. Rodent species will be discouraged from returning because of possible damage to the wastewater treatment system liners and underground piping by burrowing. This is an unavoidable impact of the conversion of open space to wastewater infrastructure. Wetlands will be protected and the impact on waterfowl by creation of possible nesting habitat is likely to be positive. 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 has been searched, and the results are attached in Figure 8. Also, in the 1999 EAW conducted for the Conservancy, the DNR Natural Heritage database was searched for the entire project site, including the proposed site of the wastewater treatment system. The data base search indicated that no threatened or endangered plant or animal species were found within one mile of the proposed wastewater treatment facility site. The construction of the wastewater treatment system will be phased so that the construction impacts will be minimized by confining construction to the smallest area possible. According to the DNR Natural Heritage Database, a record exists from 1977 indicating a potential 50-acre Oak Savanna within the proposed Conservancy development project site. Although a field survey was conducted, the limits of the oak savanna were not determined. A prairie survey on the proposed Conservancy development site has been performed to define the limits of the prairie and oak savanna area. The prairie survey included flagging the boundaries of Benton County, Minnesota 7 Worksheet

9 the survey area in the field, mapping the locations and developing a botanical survey. Five separate areas were mapped as oak savanna/open prairie. The five sites border oak and pine stands. The delineated prairie boundaries occur adjacent to the oak stands. The proposed Conservancy development project will include a proposal to preserve the prairie areas by implementing permanent conservation easements. Consequently, these areas will be surveyed and protected. A management plan will be developed for the areas. The plan will involve scheduling regular prescribed burns to control invasive species and regenerate new growth. Portions of the proposed Conservancy development will utilize walking paths and/or interpretive trails near the prairie areas, which will provide an educational tool for members of the community. 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. A water outlet structure will be placed in the wetland to allow treated wastewater to flow into the wetlands. Discussions with the DNR have taken place to determine the location, type and size of the structure. A permit is required from the DNR for the outlet control structure. No permit is required from Benton County, the DNR or other state agency under the Wetland Conservation Act, as the proposed structure falls under the minimum 400 square foot criteria. The proposed effluent limitations for this facility should be adequate to protect the designated uses of the wetland. However, there is a strong potential that the addition of treated wastewater to this wetland complex will slowly convert this sedge meadow and grassy marsh to a vegetation community dominated by tolerant aquatic plants such as cattails (Typha sp) and duckweeds (Lemna sp). Such shifts in wetland plant communities have occurred over time in other natural wetlands receiving wastewater discharges, including those in Biwabik MN; Houghton Michigan (Kadlec, Robert H. and Robert L. Knight Treatment Wetlands Lewis Publ., Boca Raton FL. pp ); and Drummond, WI (Nichols, Dale S. and Dale a. Higgins 2000 Long-term wastewater treatment effectiveness of a Northern Wisconsin Peatland. "Journal of Environmental Quality" 29: ). It is likely these changes in plant communities result from both hydrologic and nutrient effects of wastewater discharge. 13. 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. There are no existing wells on the portion of the site where the wastewater treatment facility will be located. The water demand for the wastewater treatment system is very small. Water is needed for cleaning component parts of the treatment system (commercial septic tank filters) and landscape watering. There are three options to satisfy the water needs of the wastewater treatment system. An onsite well can be installed. A pressure sprayer can be purchased to use treated wastewater for cleaning. Water can be secured from the residential development water supply. If a water supply is secured from the residential development, watering will be provided by the well supplying the development. Benton County, Minnesota 8 Worksheet

10 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. The wastewater treatment system is located next to a wetland that is not on the DNR public Waters Inventory and, therefore, is not considered shoreland under the Shoreland Management Act. 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. Not Applicable. 16. Erosion and Sedimentation. Give the acreage to be graded or excavated and the cubic yards of soil to be moved: 1 acres; 3,500 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. An erosion control plan has been developed which uses silt fencing along the boundary of the wetland in areas where grading is proposed. Seeding and mulching will be done within two weeks of final grading. 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. Storm-water runoff during construction will be minimal due to the sandy soil on site. Phasing of the construction to reduce the area impact will result in approximately 44,000 square feet of land open to construction storm-water impact. The small area proposed for construction will result in no significant runoff and water quality impacts on the adjacent wetland. Recommended practices in the Best Management Practices Handbook for Minnesota will be used in constructing silt fences. Post-construction runoff will be similar to pre-construction. The existing drainage pattern will be maintained. No significant post-construction storm-water runoff impacts are expected. 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 will be absorbed into the soil. In excessive storm events it is possible that runoff will pass overland through the silt fences to the wetland on the south and east side of the site. The purpose of the wastewater system is to service new and existing development. New development will result in increased runoff from impervious surfaces. Increased runoff can potentially cause flooding, erosion, and increased nutrients and sedimentation in nearby wetlands and streams. New development resulting in greater than five acres of disturbance will be required to obtain NPDES storm-water permits that require the application of runoff controls. The proper application of runoff controls will reduce the impact of development on the water quality. Benton County, Minnesota 9 Worksheet

11 18. Water Quality Wastewater. a. Describe sources, composition and quantities of all sanitary, municipal and industrial wastewater produced or treated at the site. All wastewater, generated from the service area, described in Figure 2, will be treated by the Benton Utility LLC. Wastewater will be from domestic, residential and commercial development. The proposed discharge is to a wetland complex in the middle of the proposed Conservancy development. The wetlands can be divided into two different areas. One area is northeast of a dike where there is open water. The other area is downstream of the dike. The proposed discharge point is immediately downstream of the dike. All water discharged from the wastewater treatment facility will meet effluent and water quality standards required by the MPCA. Design Flow The design flow (average wet weather) is 150,000 gpd and represents a maximum theoretical buildout population of 1,843. This would include all three areas described in the proposed service area. The peak hourly wet weather flow has been estimated using a peaking factor of 2.5, as recommended in the MPCA s Design Flow and Loading Determination Guidelines. Design flows are summarized in Table 1: Table 1: Design Flow - Buildout Population (Buildout) Average Wet Weather (AWW) Flow Peak Hourly Wet Weather Flow 1843 people 150,000 gpd 375,000 gpd Because of the size of the service area, it may take a number of years to reach buildout. The Benton Utility LLC has elected to take a phased approach to wastewater treatment. Phase 1 consists of a 50,000 gpd (average wet weather) treatment module. The wastewater system would be expanded, as necessary, through Phase 2 and Phase 3 (50,000 gpd each) to accommodate growth within the development. Benton Utility LLC proposes a conservative design and will monitor flow and treatment plant performance and expand if the future flow warrants increasing the capacity of the system. The treatment system is modular in design and can be expanded. The Phase 2 and 3 expansions will occur when the metered water flow reaches 80 percent of the treatment plant capacity. It is anticipated that the existing Golf Haven and Phase 1 Conservancy projects will not trigger expansion beyond Phase 1. Benton County, Minnesota 10 Worksheet

12 Design Loads Design loadings have been determined based on per-capita mass loadings as indicated in Table 2: Table 2: Design Loading - Buildout Parameter Per Capita Factor (lb/cap/day) Buildout Population Mass Loading (lb/day) CBOD TSS NH 3 -N TP 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 proposed treatment system is located adjacent to a large wetland complex. The wetland has an unlisted classification under Minn. R , subp. 4 (Classification of Waters in the Upper Mississippi River Drainage Basin) and has been assigned use classifications of 2D, 3D, 4C, 5 and 6. The 2D classification is specific to wetlands in order to protect the propagation and maintenance of a healthy community of aquatic plants and terrestrial species indigenous to wetlands and their related habitat. The wetland drains westerly approximately 0.5 miles to an unnamed stream, then about 0.6 miles to Little Rock Creek, and then flows 0.5 miles to the Mississippi River. Preliminary effluent limitations were provided by the MPCA on May 24, The proposed effluent limitations for a continuous discharge are listed in Table 3. Table 3: MPCA Preliminary Effluent Limitations Parameter Monthly Average or Range CBOD 5 25 mg/l Total Suspended Solids 30 mg/l Fecal Coliform Bacteria (1) 200 Organisms/100mL Chlorine Residual (1) mg/l PH Total Phosphorous (2) Monitor (1) Applicable year-round to protect downstream domestic water supply. If chlorine is used to achieve the effluent limitation for fecal coliform group organisms, then dechlorination must also be provided (2) Consistent with the MPCA Strategy for addressing Phosphorous, effluent monitoring is required. If total phosphorous concentrations exceeds 4.0 mg/l annual average, a Phosphorous Management Plan will be required. Benton County, Minnesota 11 Worksheet

13 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. Not Applicable. 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. Not Applicable. 19. Geologic hazards and soil conditions. a. Approximate depth (in feet) to Ground water: 20 minimum; 30 average. Bedrock: > 30 minimum; unknown 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. b. Describe the soils on the site, giving SCS classifications, if known. Discuss soil granularity and potential for groundwater contamination from wastes or chemicals spread or spilled onto the soils. Discuss any mitigation measures to prevent such contamination. Soils: SCS Classification 162, 161, 543, 1031, 7 and 328 Soil Series Name: Lino, Isanti, Markel, Seelyeville, Hubbard, and Sartel Family: Lino Aquatic Udipsamments Isanti Typpic Hapaquolls Markel Terric Borspaprist Seelyeville Typic Borosaprists Hubbard Udorthenitic Haploborollis Sartell Typic Udipsamments Source: USDA NRCS, Benton County Soil Survey, April 1996 The Benton County Soil Survey classified about 50 percent of the soils on the site as somewhat to very poorly drained. (Isanti Series 161, Lino Series 162, Markey Series 543, and Sellyville Series 1031). These soil types predominate in the southern half of the property as well as the north central part. There are two series of excessively drained soils that comprise the other half of the area (Hubbard Series 7 and Sartell Series 328). According to the Benton County Soil Survey, the high water level table occurs at 0 to 36 inches in the poorly drained soils and greater than 6 feet in the excessively drained soils. Benton County, Minnesota 12 Worksheet

14 On February 12, 1999, North American Wetland Engineering conducted a preliminary soils investigation at the site of the proposed development. In general, the soils were sandy loam to fine sand in all six of the soil pits. Mottling depth ranged from 16 inches to 66 inches. However, due to the size of the proposed development, a surface water discharge is proposed so no further soil studies were completed. 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. Benton Utilities LLC will generate septage as a byproduct of the wastewater treatment system. Septage is regulated as wastewater sludge under the EPA 503 regulations. Benton Utility LLC has the option of meeting the biosolids requirements for land spreading or to transport the septage to a municipal wastewater treatment system capable of handling septage. The nearest sewage treatment system capable of handling septage is the St. Cloud wastewater treatment system. Approximately 90,000 gallons of septage will be generated annually under full plant capacity for disposal. An agreement will be sought for disposal of septage at St. Cloud. 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 groundwater. 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. Not Applicable. 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. Not Applicable. 21. Traffic. Parking spaces added: 3 spaces Existing spaces (if project involves expansion): Estimated total average daily traffic generated: One vehicle per day Estimated maximum peak hour traffic generated (if known) and its timing: 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 traffic analysis has been conducted by the Benton Utility LLC. 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. There are no air quality non-attainment areas in Benton County. Traffic generated by Benton Utility LLC will not result in traffic congestion. Based on one trip generated the Benton Utility LLC, the potential for the generation of excessive suspended particulates or carbon monoxide from the proposed development is not possible. Benton County, Minnesota 13 Worksheet

15 Traffic increases are expected as a result of future development and will be addressed, as appropriate in future EAWs. Plans for traffic improvements on TH 10 include the construction of interstate type interchanges at two locations serving the immediate area. 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, hydrofluorocarbons, perfluorocarbons or sulfur hexafluoride). Also describe any proposed pollution prevention techniques and proposed air pollution control devices. Describe the impacts on air quality. No permanent stationary sources of air emissions are proposed. In the event of a prolonged power outage, a temporary emergency generator will be provided. Construction activities can create fugitive dust. Measures such as watering will be employed to prevent fugitive dust. 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.) Wastewater treatment systems can generate odors. In the proposed wastewater treatment system, all wastewater is contained in underground tanks, in the vertical flow wetland and in the sand filter until it is fully treated and released to the environment. Fugitive dust is a potential air quality impact. Watering of haul roads will be done to control dust. Construction activities generate noise and exhaust that can be a problem for neighboring residents. However, there will be no residents within one-fourth mile until the Conservancy development begins Phase 2. To minimize the impact of noise, construction activities will be confined to the daylight hours of 7 am to 7 pm. Proper maintenance of contractor s equipment will also prevent excessive noise and exhaust. 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 Minnesota Historical Society was contacted to request a search of their inventory for the wastewater treatment facility and their response is included in Figure 7. Benton County, Minnesota 14 Worksheet

16 However, in the 1999 EAW conducted for the Conservancy, the Minnesota Historical Society database was searched for the entire project site and no sites were found. Two sites were listed near the service area of Benton Utilities. The Little Rock South Site and the Little Rock Lake Village Area were identified. The precise location of the sites is being sought from the Minnesota Historical Society to determine if they are within the service area. 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. The project complies with the Benton County Comprehensive Plan 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.) The Benton Utility LLC is proposed to be a Sanitary Sewer District, which is a new utility. Electric service will be supplied to the wastewater system from existing transmission lines adjacent to the Conservancy. As a result of new development there will be increased pressure on infrastructure, such as roads, gas, telephone, electric, schools, hospitals, emergency services, police, and fire protection. These impacts will be discussed in the Conservancy EAW and can be addressed in subsequent environmental review of other development that may be stimulated by the proposed 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). Item number 6.d. and item number 7. discuss developments within the service area of the Benton Utility. Services to the developments in the service area will be provided based on development demand and after processing of the necessary permits and approvals from the various permitting agencies. The potential for future environmental effects by development served by the Benton Utility will be addressed by future environmental review and permitting requirements which may be applied by state or local jurisdictions. 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 have been identified. Benton County, Minnesota 15 Worksheet

17 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. Water Quality - Wastewater Construction of the Benton Utilities wastewater treatment system will result in the discharge of 150,000 gpd of treated wastewater to waters of the state. The discharge will be to a wetland complex tributary to the Mississippi River. Water Quality - Storm Water The area served by the Benton Utilities is approximately 615 acres. This area will ultimately be developed according to the Benton County zoning laws. As development occurs construction site runoff will be managed according to the MPCA Storm Water General Permit. The immediate area of construction for the wastewater treatment system is 7.7 acres. Potential stormwater runoff effects from the development within the Benton Utilities service area and at the wastewater construction site will be mitigated by the application of practices recommended in the Best Management Practices Handbook for Minnesota. Construction Dust and Noise There is the potential for noise and dust to be generated by construction activities. Proper application of water to control dust will reduce the impact of dust to a minimum. This, along with the distance to the nearest receptor being more than one-fourth mile, will result in no significant adverse impact. Noise will be controlled by minimizing the construction activities to daylight hours. Proper maintenance of the contractor s equipment will prevent excessive noise and emissions. Ecologically Sensitive Areas While there are no ecologically sensitive areas on the site of the Benton Utilities wastewater treatment site, an Oak Savanna/Open Prairie has been located on the site of the proposed Conservancy development that will be served by Benton Utilities. The prairie has been located and surveyed. The prairie area will be set aside by a conservation easement and managed for educational and interpretive purposes. Benton County, Minnesota 16 Worksheet