Southeast Waconia Area Sanitary Sewer Interceptor ... · Note to reviewers: The Environmental...

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ENVIRONMENTAL ASSESSMENT WORKSHEET Note to reviewers: The Environmental Assessment 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) 297-8510. An electronic version of the completed EAW is available at the MPCA Web site http://www.pca.state.mn.us/news/eaw/index.html#open-eaw. 1. Project Title: Southeast Waconia Area Sanitary Sewer Interceptor 2. Proposer: City of Waconia 3. RGU: Minnesota Pollution Control Agency Contact Person John Hilgers Contact Person Dana Vanderbosch and Title Planning Director and Title Project Manager Address 201 South Vine Street Address 520 Lafayette Road North Waconia, Minnesota 55387 St. Paul, Minnesota 55155 Phone (952) 442-3106 Phone (651) 297-1796 Fax (952) 442-2135 Fax (651) 297-2343 4. Reason for EAW Preparation:

EIS Scoping

Mandatory EAW

X

CitizenPetition

RGU Discretion

Proposer Volunteered

If EAW or EIS is mandatory give EQB rule category subpart number and name: Minn. R. 4410.4300,

subp. 18 (A) 5. Project Location: County Carver City Waconia 1/4 1/4 Section See below Township See below Range See below

The project extends through or along the borders of T116N, R25W, Section 24 and T116N, R24W, Section 19.

http://www.pca.state.mn.us/news/eaw/index.html#open-eaw

Southeast Waconia Area Sanitary Sewer Interceptor Environmental Assessment Waconia, Minnesota 2 Worksheet

Figures and Attachments for the EAW: Figure 1 Map showing the general project location in Carver County, Minnesota; Figure 2 United States Geological Survey 7.5 minute, 1:24,000 scale map indicating project location; Figure 3 Service Area of the Southeast Waconia Area Sanitary Sewer Interceptor overlaid on an aerial

photograph; Figure 4 National Wetland Inventory (NWI) map, Federal Emergency Management Agency and

Protected Waters Inventory (PWI) in Project Area; and Figure 5 Site soils map. Attachment A Minnesota Historical Society’s State Historic Preservation Office (SHPO) e-mail dated

February 16, 2006; and Attachment B Minnesota Department of Natural Resources (DNR) Natural Heritage and Nongame

Research Program Response letter dated February 22, 2006.

6. Description:

a. Provide a project summary of 50 words or less to be published in the EQB Monitor. The city of Waconia (City) is proposing construction of the Southeast Waconia Area Sanitary Sewer Interceptor, which will connect to the Highway 5 Interceptor located at the intersection of Trunk Highway (TH) 5 and County State Aid Highway (CSAH) 30. The project will consist of a lift station, 4,871 feet of 36-inch gravity sanitary sewer pipe, and 1,830 feet of 16-inch sanitary sewer force main and will convey an average daily wastewater flow of 2.98 million gallons per day (mgd).

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. The project will consist of the construction of 4,871 feet of 36-inch gravity sanitary sewer pipe, a lift station, and 1,830 feet of 16-inch sanitary sewer force main to convey wastewater from the southeast portion of the City to the Metropolitan Council Environmental Services (MCES) - Blue Lake Wastewater Treatment Facility (WWTF) in Shakopee, Minnesota (Figures 1 and 2). The lift station and force main will pump wastewater to the top of the ridgeline along CSAH 10 and convey flows by gravity from southeast Waconia to the existing TH 5 interceptor located along the southerly right of way of TH 5. The service area for the Southeast Waconia Area Sanitary Sewer Interceptor will include residential and commercial development to be located southeast of the City. The development plan was analyzed in the Southeast Waconia Alternative Urban Areawide Review (AUAR), which was finalized in February 2006. The proposed project will be sized to accommodate average daily wastewater flows of 2.98 mgd and 7.4 mgd under peak capacity from a mix of residential and commercial buildings (10,840 equivalent residential units) from a population of approximately 29,810. The project will be timed so that it will be compatible with four separate upcoming construction projects that will reroute existing streets. The north 600 feet of the gravity pipeline will be constructed as part of the CSAH 30 construction project (which will connect TH 5 and CSAH 32/10) in the summer/fall of 2006. The remaining portion of the gravity sewer (approximately 4,400 feet) and the northernmost 300 feet of the force main is proposed as part of the City Trunk Utility project also in the summer/fall of


2006. The southernmost portion of the force main will be constructed as part of the Carver County Highway Department’s CSAH 10 Realignment project. This project is scheduled to begin in the summer of 2006 and continue through the 2007 construction season. The final portion of the project, construction of the lift station, is scheduled for 2007. Figure 3 shows the service area overlaid on a map of existing and future streets. Construction of the proposed project will involve grading, excavation, backfilling, potential de-watering, and re-vegetation activities. Pipe will be laid in trenches; soil removed will be backfilled after the pipe has been laid. The gravity sewer trenches will be 30 feet deep on average; the force main will be laid 10 feet deep on average. Equipment to be used will include standard construction machinery such as trucks, backhoes, graders, compactors, bobcats, cranes, loaders, compressors, and possibly de-watering pumps. Coordinating construction of the interceptor and road project will serve to minimize or limit disruption to the environment as well as to people in the area.

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 proposed project will convey future wastewater flow from the southeast portion of the City immediately adjacent to the proposed alignment (Figure 3). Eventual beneficiaries of the project will include residents and business operators in these areas.

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. Local sewers will be constructed as needed to connect residential and commercial developments to the Southeast Waconia Area Sanitary Sewer Interceptor. The locations of these local sewer lines have not been determined yet; the locations will depend on where and when development occurs. This EAW only covers the Southeast Waconia Area Sanitary Sewer Interceptor and not future connections. Depending on their individual capacities, additional environmental review may be needed for the local trunk sewers.

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.

7. Project Magnitude Data Total Project Area (acres) 9.2 acres or Length (miles) ~ 1.3 miles Number of Residential Units: Unattached 0 Attached 0 maximum units per building NA Commercial/Industrial/Institutional Building Area (gross floor space): total square feet 0 Indicate area of specific uses (in square feet): Office 0 Manufacturing 0 Retail 0 Other Industrial 0 Warehouse 0 Institutional 0 Light Industrial 0 Agricultural 0 Other Commercial (specify) 0 Building height NA If over 2 stories, compare to heights of nearby buildings NA 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.

TABLE 8-1

LIST OF REQUIRED PERMITS AND APPROVALS Unit of Government Type of Application Status U.S. Army Corps of Engineers (USCOE)

Section 404 Permit for dredging and filling of navigable waters/jurisdictional wetlands To be submitted

MPCA Sewer Extension Permit Submitted and under review

MPCA National Pollutant Discharge Elimination System (NPDES) General Stormwater Permit for Construction Activities

To be submitted

MPCA Section 401 Water Quality Certification of USCOE Section 404 Permit To be submitted

DNR Natural Heritage and Nongame Database Review Completed

DNR General Permit 97-0005 for Temporary Water Appropriations

To be submitted, if needed

DNR Public Waters Work Permit To be submitted SHPO Archeological and Historical Review Completed Minnesota Department of Transportation

Utility Permit on Trunk Highway Right of Way (Form 2525) To be submitted

Carver County Utility Construction on County Highway Right of Way To be submitted

Carver County Approval of Grading Plan, Sediment and Erosion Control Plan To be submitted

City of Waconia Project plan approval To be submitted

City of Waconia Certificate of Wetlands Conservation Act (WCA) Exemption To be submitted

City of Waconia Plat approval for lift station To be submitted City of Waconia Building Permit for lift station 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. Land use adjacent to the proposed Southeast Waconia Area Sanitary Sewer Interceptor is primarily agricultural or rural residential at this time. The project will generally be located in an area transitioning in land use from agricultural and rural residential to urban. It is compatible with existing and proposed land uses in the area. Review of MPCA databases has revealed no abandoned or contaminated sites within 0.5 mile of the proposed project. There are no known potential environmental hazards in the vicinity.


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 0.16 0.16 Lawn/landscaping Wooded/forest 1.58 1.58 Impervious Surfaces Brush/grassland 0 0 Other (describe) Cropland 7.46 7.46 TOTAL 9.2 9.2

Land to be disturbed to install the pipeline will be restored to its current condition. Approximately 0.16 acres of wetland may be impacted to install the lift station. Though the table above indicates a 1:1 mitigation scenario, any wetland impact will actually be mitigated 2:1.

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. Fish and wildlife species are likely to include those species common to agricultural and developing areas. Species might include fox, deer, muskrat, rabbit, mice and other small rodents, geese, ducks, raptors, a variety of other common bird species, and small reptiles. Amphibians and small fish may also be present in wetland areas. Short-term impacts on wildlife will include the disruptive effects of construction, including excavation, stockpiling of soils and materials, noise, potential erosion and sedimentation, and vehicle movement. Seasonal activities such as nesting may be disrupted or curtailed, depending upon the season of construction. The project itself will not permanently displace wildlife. Soil removed to lay pipe will be backfilled and the soil surface will be revegetated. Urban development enabled by the sanitary sewer line will cause a shift in the species present. Species tolerant of urban areas will remain, while others less tolerant will not. These broader impacts were discussed in the Southeast Waconia AUAR. Permits/approvals requiring mitigation measures include the NPDES General Permit for Construction Activities, the Carver County approval of the Grading Plan and Sediment and Erosion Control Plan, and the Certificate of Exemption for temporary wetland impacts to be obtained from the local government unit (LGU), if applicable. These and other permits listed in Item 8 of this EAW will include specific mitigation measures to be provided for erosion and sediment control, stormwater runoff, and potential wetland impacts. Measures will include erosion control best management practices (BMPs) such as use of erosion control blankets and prompt re-vegetation of disturbed areas.

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 20060611 Describe measures to minimize or avoid adverse impacts.


The DNR’s Minnesota Natural Heritage and Nongame database has been reviewed to determine if any rare plant or animal species or other significant natural features are known to occur within an approximate one-mile radius of the proposed area to be disturbed. The review identified a mature maple-basswood forest and a colonial waterbird nesting site located near the proposed alignment, but based on the nature and location of the proposed project, the DNR does not believe these species will be affected by the project (Attachment B).

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 PWI number(s) if the water resources affected are on the PWI. Lift Station: According to the NWI Map, construction of the proposed lift station will impact ~0.16 acres of the wetland designated as DNR Public Water 10-60P (Figure 4). This construction will require several permits including a Section 401 Certification from the MPCA, a Section 404 permit from the USCOE, and a DNR Work in Public Waters Permit. Additionally, a Certificate of WCA Exemption from the LGU – the City – would also be required. Prior to construction, the wetland will be delineated to ascertain the exact impact size. Wetland permit applications will be prepared and submitted to the City and to the USCOE to obtain authorization for wetland alterations under the WCA and Sections 401/404 of the Federal Clean Water Act prior to project construction. Wetland applications and designs will undergo additional review and comment by the DNR, the Board of Water and Soil Resources, and the Carver County Soil and Water Conservation District. Wetland impacts will be replaced in compliance with the Minnesota WCA and the Federal Clean Water Act. Under WCA, a minimum of 2:1 wetland replacement is required to compensate for wetland alteration including filling and drainage. At least the first 1:1 wetland replacement must be in the form of New Wetland Credit to satisfy WCA requirements. A detailed wetland alteration and replacement plan has not been completed for this project; therefore, the extent of mitigation is not known at this time. Wetland replacement will either be designed to expand upon existing on-site wetlands, created in conjunction with stormwater ponding, or credits will be purchased from a local wetland bank. On-site wetland replacement will be explored as the first alternative for compensatory mitigation. Pipeline: The pipeline will come within close proximity to known wetlands. In addition, other wetlands not identified by the NWI may also be present along the alignment. Prior to construction, wetlands near the project alignment will be delineated. If wetlands cannot be avoided, approval for temporary impacts to wetlands will be obtained from the appropriate agencies prior to initiation of construction activities. This approval process would be the same as that described above for construction of the lift station. Since pipeline installation would result in the temporary disruption of wetlands for the purpose of installing pipeline, mitigation would consist solely of restoration of disturbed wetlands. Original grade contours would be restored after construction and, therefore, pre-construction drainage patterns would not be anticipated to be altered by the project. Wetland vegetation would be restored by seeding with a native wetland seed mix.


Whether wetlands will be located directly within the path of construction or not, their proximity to the construction site means that erosion control will be important. An NPDES General Stormwater Permit for Construction Activities will be obtained, as required from the MPCA. As part of the permit application, temporary and permanent erosion and sediment control plans will be prepared. The sediment and erosion control plans will provide more detail as to the specific measures to be implemented and will also address phasing of construction, vehicle tracking of sediment, inspection of erosion control measures, and the time frames in which the erosion control measures will be implemented. Special measures that will be implemented to ensure no runoff from the site flows to the wetlands prior to site stabilization may include machine sliced installation of silt fence. In addition, the installation of wattles (alone and/or in conjunction with riprap), use of erosion control blankets, turf reinforcement mats, and riprap in two configurations to attenuate erosive energy would allow prompt establishment of a vegetative soil stabilization system. Some of the wetlands may be due to perched water table conditions. Soil borings and site observation during construction will be used to check for horizontal confining layers creating a perched wetland that could be penetrated by the trench and drained. If these conditions are observed, trench dams will be incorporated into the project to prevent unintentional draining of wetland areas through or near which the alignment passes. A horizontal confining layer of low-permeability soils will also be restored, if soil borings and site observation during construction confirm the presence of perched wetlands. In general, native soils will be used as backfill material, and nearly all of this material consists of loams.

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 de-watering)? Yes No (potential de-watering and well abandonment) 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. According to information obtained from the County Well Index, there are domestic water wells at several residences along the proposed project alignment. At this time, it is not known if abandonment of any of these wells will be needed due to 50-foot separation requirements. Appropriate measures will be taken to maintain required separation distances. If it is determined that domestic water wells are present within minimum setbacks from the final alignment, they will be properly abandoned in accordance with Minnesota Department of Health regulations. Braun Intertec completed soil borings for residential developments in the vicinity of the project area. Ground water was encountered at depths up to 4 to 19 feet below the ground surface; it is likely that the water observed represented perched ground water in some areas of the site. Temporary de-watering wells are not anticipated to be widely needed due to the clay and sandy lean clay soils present, but may be needed in some areas in order to place the interceptor pipe at the required depths. It is not yet known if the volumes of water would be such that a DNR permit for temporary de-watering would be required. If de-watering at the site exceeds 10,000 gallons per day or 1,000,000 gallons per year, a temporary Water Appropriations Permit will be obtained from the DNR and the proposer will comply with all requirements of that permit.


If a trench box is used during construction, water would be either pumped out of or diverted around the construction trench. De-watering discharge would be directed to sediment traps or vegetative buffer strips if the discharge is laden with sediment. A filter sock may also be used to trap the sediment and filter the water prior to discharge. If de-watering wells are needed, clean discharge from well point de-watering would be dissipated over the adjacent wetland areas located beyond the construction limits.

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: 9.2 acres; 200,000 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.

Assuming 30 feet average depth of gravity sewer, 10 feet average depth of force main, and 1:1 trenches, approximately 200,000 cubic yards of soil is to be removed and replaced during construction. According to Carver County soil survey information, some of the soil types identified in the project alignment are indicated to be eroded. (These soil types include a “2” at the end of their mapping symbol – more detail provided in Item 19 and on Figure 5.) Steep slopes are generally considered to be slopes greater than 12 percent. Soils with slopes greater than 12 percent are identified as KD2 and KE2 by Carver County soils information in the project alignment (Item 19 and Figure 5). Regardless of the soil erosion potential, erosion control measures will be implemented. The project proposer will be required to obtain a NPDES General Stormwater Permit for Construction Activities from the MPCA to control erosion and runoff during construction. This permit must be obtained prior to commencing any land disturbing activities (i.e., clearing, grading, filling and excavating) at the site. The permit specifically requires implementation of BMPs. Specific measures to be used will be detailed in the erosion control plans required as part of the NPDES Permit application. In general, high flow areas will be protected with turf reinforcement mats. Any potential high flows from off site will be mitigated as they enter the construction site. Measures may include the use of high flow silt fence, check dams, biologs, and/or stilling basins. Regular inspection will insure that measures implemented remain effective. Disturbed areas will be seeded and stabilized as soon as possible after construction. A fiber blanket or hydraulic seed stabilizer may also be used. Minimizing disturbance and phasing of the proposed project, along with diligent temporary stabilization of all slopes and areas of exposed soil, will be necessary to prevent erosion and the discharge of sediment to state waters. The majority of excavated soil will be returned to the construction trench after placement of the pipe. Any excess soil will be disposed of in upland areas where sediment will not impact water resources or other sensitive areas. Construction practices will be managed to limit the duration of exposed soil to wind and rain.


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. Since sewer pipe will be buried, the quantity and quality of runoff before and after the project will not change significantly. The NPDES General Stormwater Permit for Construction Activities is intended to mitigate the potential for erosion and sedimentation both during and after completion of construction. Discharge from potential de-watering activities during excavation is discussed in Item 13.

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. Receiving water bodies in the vicinity of the proposed project include wetlands and Reitz Lake. The watershed discharges into an outlet creek from Reitz Lake into an unnamed tributary to the Minnesota River. As discussed in Items 12 and 16 of this EAW, appropriate erosion and sediment control measures will be implemented during construction, and runoff from the site will be minimized. Considering the disturbance caused by construction of the pipe will be temporary and since the sewer pipe will be placed below grade, significant impacts to receiving water bodies are not anticipated. Vegetation will be restored as soon as possible after construction. Fiber blankets, mulch and/or hydraulic seeding will be used where necessary to ensure prompt re-vegetation. The NPDES General Stormwater Permit for Construction Activities will outline specific time line provisions for re-vegetation. The contractor will comply with these time lines.

18. Water Quality – Wastewater. a. Describe sources, composition and quantities of all sanitary, municipal and industrial wastewater

produced or treated at the site. The Southeast Waconia Area Sanitary Sewer Interceptor has been sized to accommodate average wastewater flows from residential and commercial developments of 2.98 mgd (7.4 mgd under peak conditions) and will convey sanitary wastewater from the southeast portion of the City to the MCES - Blue Lake WWTF. Wastewater to be conveyed by the completed interceptor project will be within the range of normal strength domestic wastewater

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. Portions of the project service area currently do not have centralized wastewater treatment and collection service. As discussed previously, the project will allow the discharge of domestic strength wastewater to the MCES – Blue Lake WWTF, which has an authorized discharge to the Minnesota River under NPDES/State Disposal System (SDS) Permit no. MN 0029882. The Minnesota River


ultimately flows into the Mississippi River. Since the limits and conditions within the NPDES/SDS Permit are intended to protect the quality of the receiving water, the proposed project is not anticipated to result in significant impacts to the Minnesota River.

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. Sanitary sewer waste will be conveyed via the Southeast Waconia Area Sanitary Sewer Interceptor to the MCES - Blue Lake WWTP. The MCES is fully aware of this proposed project and the development it will enable. The Blue Lake WWTF operates in compliance with the effluent limits and operating conditions contained in its NPDES/SDS Permit no. MN 0029882. Its average wet weather design flow capacity is 38 mgd and it is presently treating approximately 26 mgd. There is adequate capacity to manage additional wastewater to be conveyed by the proposed project.

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: 0 ft minimum; 105 ft average. Bedrock: ~ 200 ft minimum; 400 ft 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. Depth to bedrock is 200-300 feet in the southern two-thirds of the southeast Waconia area and 300-400 feet in the northern one-third (USGS Depth to Bedrock, 2001) of the southeast Waconia area. Eight wells located within Section 24 (T116N, R25W) and 14 wells located within Section 19 (T116N, R24W) showed a range in depth to ground water of 65 to 150 feet, with an average depth of 105 feet (County Well Index, Minnesota Geologic Survey, 2004). Since some wetlands in the southeast Waconia area encounter surficial ground water, the minimum depth to ground water is estimated at zero feet. Sinkholes, shallow limestone formations, karst conditions, or other geologic site hazards are not known to be present along the project alignment.


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. According to the Southeast Waconia AUAR, the digital Soil Survey of Carver County [U.S. Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS), 2005] identifies 29 soil map units within the AUAR area. Of these 29, nine are located on the project alignment (Table 19-1). The locations of the soil types are shown on Figure 5.

TABLE 19-1 SOIL CHARACTERISTICS

Map Unit

Soil Type Slope (%) K Factor1 Erodibility2 Hydrologic Group3

HM Hamel loam 0-2 0.28 NHEL B/D

KB2 Lester-Kilkenny loams, eroded 2-6 0.28 NHEL B-C

KC2 Lester-Kilkenny loams, eroded 6-12 0.28 PHEL B-C

KD2 Lester-Kilkenny loams, eroded 12-18 0.28 HEL B-C

KE2 Lester-Kilkenny loams, eroded 18-25 0.28 HEL B-C

LA Le Sueur-Lester loams 1-4 0.24 NHEL B

LS Le Sueur loam 0-2 0.24 NHEL B

MK Houghton and Muskego soils 0-2 0.02 NHEL A/D

PM Klossner muck 0-2 0.02 NHEL A/D 1 Erosion Factor K indicates the susceptibility of a soil to sheet and rill erosion by water.

Values of K range from 0.00 to 0.28; the higher the value, the more susceptible the soil is to such erosion.

2 HEL = Highly Erodible Land, NHEL = Not Highly Erodible Land, PHEL = Potentially Highly Erodible Land.

3 Hydrologic soil groups are used to estimate runoff from precipitation: A – high infiltration rate, low runoff potential; B – moderate infiltration rate; C – slow infiltration rate, D – very slow infiltration rate, high runoff potential.

The most abundant soil type in the southeast Waconia area is Lester-Kilkenny loams with 2 to 40 percent slopes, occupying approximately 33 percent of the area. Lester soils consist of very deep, well-drained soils that formed in calcareous loamy glacial till on till plains and moraines. They have moderate permeability, and runoff is medium to high. Kilkenny soils consist of very deep, moderately well-drained soils that formed in a mantle of clayey glacial till and underlying loamy glacial till on moraines. They have moderately slow permeability, and runoff is medium to very high. The second and third most frequent soil types are classified as hydric soils. The Cordova-Webster complex, located along the west-central southeast Waconia area boundary, occupies approximately


12 percent of the area. Houghton and Muskego soils occupy another 12 percent of land at the southern end of the southeast Waconia area. Cordova-Webster soils are poorly drained while Houghton and Muskego soils are very poorly drained. The sensitivity of ground-water systems to pollution is indicated by the approximate time it takes water to infiltrate the land surface until it is discharged or pumped from an aquifer. The potential for ground-water contamination is estimated to be low to moderate based on the permeability of the dominant soil types found on the site. Although shallow ground water is highly susceptible to contamination, moderately permeable soils with finer textures will slow or restrict the movement of water, which extends the time needed for chemicals to break down before reaching the water table. Since development within the southeast Waconia area will be typical of residential and commercial land uses, no unusual wastes or chemicals are anticipated to be spread or spilled onto the soils that would cause significant ground-water contamination. According to the Wellhead Protection Plan (Bolton & Menk, Inc., 2004), the principle potential source of contamination to the well water is other wells that reach or penetrate the aquifers that the City uses for its public water supply. In order to prevent contamination due to these other existing wells, all wells found during development of the southeast Waconia area will be properly abandoned. Farmsteads will be connected to the City’s water mains when the development reaches them, and no new private wells will be installed.

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. Construction activities will generate construction waste materials. These materials will be disposed of by the contractor in accordance with applicable state and local rules and regulations.

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. During construction, equipment and vehicles utilizing gasoline, diesel fuel, antifreeze, and oil will be used at the project site. Portable storage tanks of fuel may be temporarily located at the site during construction. Fueling of vehicles and equipment will be conducted away from sensitive areas.

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. As discussed above, portable storage tanks of fuel may be temporarily located at the site during construction. Refueling of construction equipment will take place from tanker trucks, and will occur in areas that are not environmentally sensitive. A spill kit will be kept on the construction site. The kit will include shovel, kitty litter or sorbent pads, gloves and plastic sheeting. If the spill is small, it can be contained with kitty litter or sorbent pads. If it is large, dikes will be constructed to contain the spill and minimize environmental damage. If a spill over five gallons occurs, the State Duty


Officer will be notified. The wastes associated with the spill will be properly disposed of at a facility for energy recovery.

21. Traffic. Parking spaces added: 0 Existing spaces (if project involves expansion): 0 Estimated total average daily traffic generated: NA Estimated maximum peak hour traffic generated (if known) and its timing: NA 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. During the construction process, construction vehicles will be utilizing county roads and local streets. Delivery of pipe, concrete and other materials will be restricted to the county roads, where possible.

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. Vehicle emissions directly associated with the project will not have a significant effect on air quality; however, residential and other development enabled by the construction of wastewater conveyance capacity may result in measurable, but not likely significant impacts.

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. Not applicable.

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.) Dust and noise will be generated by equipment and machinery during construction. Odors may also be generated from construction equipment exhaust. Equipment will include trucks, backhoes, graders, compactors, bobcats, cranes, loaders and compressors. Dust will most likely be controlled by daily cleanup of the construction site, and water will be used to wet the soil and reduce airborne dust when necessary. Noise and odor impacts from construction equipment will be controlled by restricting the hours of operation to daylight hours, or those permitted by local ordinances. The nearest receptors are businesses, farmsteads and residences along TH 5 and CSAH 10. Other scattered residences and farmsteads in the project vicinity could also be affected. Average exposure times are estimated to be approximately four to eight weeks. As in any sanitary sewer system, there is potential for odors to form during operation of the proposed system. Hydrogen sulfide has the potential to form in sewage material under anaerobic conditions, and can produce a rotten-egg odor, particularly where flow turbulence releases gas from solution in the


wastewater. This project is similar to most sanitary sewers in the Metropolitan area, where slopes are mild and turbulence is low, which helps minimize the release of odors. The need for odor control is not anticipated for this project; however, if odor control becomes necessary in the future, there are a number of options to consider, such as adding chemicals to the sanitary system to suppress growth of odor-causing bacteria, and filtering air ventilated from the sewer system through a biofilter or through a carbon filtration system.

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.

Archaeological, Historical, or Architectural Resources. The SHPO was contacted regarding the potential presence of cultural resources in the project corridor vicinity. The response received from SHPO is provided as Attachment A. Two archaeological sites, a cemetery and six historic properties were identified in a search of the Minnesota Archaeological Inventory and Historic Structures Inventory for the search area requested. Of the listed sites, neither the archaeological sites nor the cemetery are in the vicinity of the alignment. There are five farmsteads or houses that are in the same quarter-quarter section as the alignment. Of these, only one will be served by the sewer. The sewer pipe will be placed more than 150 feet from the house. The digging of the trench for the sewer extension in the vicinity of the house, as well as the trench for the individual connection to the house, will be carefully done to prevent vibrations from damaging the home. The alignment is not anticipated to impact the facade or the structure of the house. There may be temporary visual or odor impacts during the actual trenching and installing of the connections to the house, but these impacts will be of short duration. Ambient dust will be contained during construction by spraying water on the work site. No permanent visual or odor impacts to the house are expected. Prime or Unique Farmlands, Lands within an Agricultural Preserve. According to the Prime and Other Important Farmlands of Carver County, Minnesota (USDA NRCS, 2005), the sewer alignment contains five soil units classified as prime farmland. These soils are Lester-Kilkenny loam, Le Sueur-Lester loam complexes, and Le Sueur loam. Hamel loam is considered prime farmland when drained. There are two soil units along the sewer alignment that are classified as farmland of statewide importance: Houghton and Muskego soils and Klossner muck. All of this land will ultimately be converted to non-agricultural land use as a consequence of land market value and the demand for housing. Designated Parks, Recreation Areas or Trails. Although the interceptor does not pass directly through any parks, it may cross areas of existing or proposed trails. Permanent impacts to these amenities are not anticipated as the project will be placed below grade, though temporary indirect impacts (such as noise, dust, and general disruption caused by construction machinery) may occur to users of the parks and trails during construction of the project. These impacts are expected to be short-lived and not significant.


Scenic Views and Vistas. The project corridor is surrounded by agricultural areas and rural residences. Scenic views and vistas are not considered present in the immediate area of the proposed project. Due to the sub-grade nature of the project, any scenic views and vistas that might be present would not be impacted once construction has been completed. Other Unique Resources. None known.

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 proposed project is subject to the City of Waconia’s Comprehensive Plan and Comprehensive Sewer Plan as well as to Metropolitan Council plans for sanitary sewer service. Upon completion of environmental review for the proposed project, the City will have to amend its comprehensive plan to incorporate this project. The service area (Figure 3) for the new Southeast Waconia Area Sanitary Sewer Interceptor will include residential and commercial development, which was analyzed in the Southeast Waconia AUAR, finalized in February 2006. Carver County, acting as the water management authority for the Crow River watershed, requires mitigation of development activities through its Water Resource Management Rules (Ordinance #57-2005). The City has developed an ordinance for Environmental Protection Regulations regarding wetlands (Ordinance 900.06.8) and an ordinance that discusses stormwater systems in new subdivisions (Ordinance 1000.06, Subd. 9). They also have developed a draft Stormwater Management Plan, which has been submitted to the County for approval. The approval process is ongoing and the City will continue to work with the County to adopt a plan that meets the County’s rules and regulations. Until a Stormwater Management Plan has been adopted, any development within the City must comply with state and county regulations. The Metropolitan Council has provided the city with 2010, 2020 and 2030 growth projections as part of their 2005 System Statements. The Metropolitan Council can provide services to this area of the city as long as their total development stays within these projections. City staff has confirmed that the City will follow this framework.


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.)

29. Cumulative impacts. Minn. R. 4410.1700, 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 potential environmental impacts that may be caused by the development that will be enabled as a result of the Southeast Waconia Area Sanitary Sewer Interceptor will include residential and commercial development to be located southeast of the City and analyzed in the Southeast Waconia AUAR, which was finalized in February 2006. Although the Southeast Waconia Area Sanitary Sewer Interceptor will not require additional infrastructure, the development planned for its service area will. As development of the area progresses, other utilities and infrastructure, such as roads, collector streets, collector sewers, potable water distribution systems, stormwater collection and treatment systems, schools, police, fire protection, and other urban services will be needed to service the area. Each of the communities’ comprehensive plans will ensure coordination of infrastructure for enabled development. During the AUAR process, it was noted that Reitz Lake has been designated as impaired for excess nutrients by the MPCA. A draft Total Maximum Daily Load (TMDL) study was recently completed by Carver County to determine the phosphorus load source reductions that will need to occur in order for Reitz Lake to achieve water quality standards. The draft TMDL recognizes that since large portions of the Reitz Lake watershed (including areas within the Southeast Waconia AUAR region) are expected to develop in the next 20 years, it will be necessary to control the resulting stormwater. Stormwater from development in the AUAR area will be collected and treated in wet regional retention basins before being discharged to surface waters. The dead storage volumes in these regional basins are sized to meet the criteria recommended in Design Calculations for Wet Detention Ponds (Walker, 1987). This design provides for 85-95 percent removal of suspended solids, 40-70 percent removal of phosphorus, and 60-80 percent removal of nitrate nitrogen. The maintenance schedule will be to evaluate/maintain the ponds in a rotating schedule (i.e., each pond would be evaluated approximately every three to five years and maintained, if needed). This plan is included in the City's Stormwater Management Plan, which has been submitted to the County for approval. The City is aware that the final TMDL may result in the need to implement higher nutrient removal efficiencies for stormwater pretreatment facilities within the Reitz Lake watershed than the current NPDES General Stormwater Permit and the draft Stormwater Management Plan specify. Though what the final TMDL may require is unknown at this time, the City will work closely with Carver County to ensure that needed nutrient reductions defined in the final TMDL will be implemented.

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WACONIASOUTHEAST WACONIA AREA

SANITARY SEWER INTERCEPTORLOCATION MAP

FIGURE NO. 1FEBRUARY, 2006

D a k o t aD a k o t a

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SANITARY SEWER INTERCEPTORFEMA, NATIONAL WETLANDSINVENTORY, & PROTECTED

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Map Document: (H:\Waca\C1237713\Arcview\37713-Soils.mxd)2/10/2006 -- 11:49:07 AM


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FIGURE 5

Southeast Waconia Area Sanitary Sewer Interceptor ... · Note to reviewers: The Environmental...

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