pipestone wwtf expansion environmental assessment worksheet · 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 651-757-2101. 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: Pipestone Wastewater Treatment Facility Expansion 2. Proposer: City of Pipestone 3. RGU: Minnesota Pollution Control Agency Contact Person Lance Weatherly Contact Person Nancy Drach and Title Banner & Associates, Consultant and Title Planner Principal Address 2307 West 57th Street, Suite 102 Address 520 Lafayette Road North Sioux Falls, South Dakota 57108 St. Paul, Minnesota 55155-4194 Phone 605-977-6342 Phone 651-757-2317 Fax 605-977-6344 Fax 651-297-2343 E-mail [email protected] E-mail [email protected] 4. Reason for EAW Preparation:

EIS Scoping

Mandatory EAW

X

Citizen Petition

RGU Discretion

Proposer Volunteered

If EAW or EIS is mandatory give EQB

rule category subpart number and name:

Minn. R. 4410.4300, subp. 18.B Wastewater systems 5. Project Location: County Pipestone City/Twp Sweet Township 1/4 NW 1/4 Section 15 Township 106 North Range 46 West

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

Pipestone Wastewater Treatment Facility Expansion Environmental Assessment Pipestone, Minnesota 2 Worksheet

Tables, Figures, and Appendices attached to the EAW: • Figure 1 – County map showing the general location of the project • Figure 2 – U.S. Geological Survey 7.5 minute, 1:24,000 scale map indicating project • Figure 3 – Minnesota Department of Natural Resources (DNR) Database - Consultant Review Map

(DNR data of May 8, 2009) • Figure 4 – Site plan showing all significant project and natural features • Figure 5 – DNR Natural Heritage ERDB Letter #20100298 and index report, dated November 18, 2009 • Figure 6 – U.S. Fish and Wildlife Service (USFWS) letter dated January 22, 2010

6. Description:

a. Provide a project summary of 50 words or less to be published in the EQB Monitor.

The city of Pipestone (City) is proposing to expand their existing wastewater treatment facility (WWTF). The City’s existing WWTF is a four-cell stabilization pond system with a design 30-day average wet weather flow (AWWF) of 0.60 million gallons per day (mgd). The City is proposing to add two new stabilization ponds adjacent to the existing WWTF, in addition to piping, structures, and other improvements (Project). The Project will increase the design capacity of the WWTF to 0.930 mgd and will allow future commercial, industrial, and residential development in the City.

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 City is proposing to expand its existing WWTF, located in the northwest quarter of Section 15,

Sweet Township west of Pipestone (see Figures 1 and 2). The expansion of the WWTF will provide improved and additional wastewater treatment capacity for both existing and future growth in the community.

The existing WWTF and the proposed expansion are shown in Figure 4. The AWWF of the existing WWTF is 0.630 mgd. The WWTF has a controlled, seasonal discharge to

Pipestone Creek, which is a class 2C, 3C, 4A, 4B, 5, 6 water. The AWWF capacity of the expanded WWTF would be 0.930 mgd. The WWTF would continue to

have a controlled seasonal discharge to Pipestone Creek.

Existing Facility Description The City’s existing wastewater system includes a WWTF that consists of a four-cell stabilization pond system, a collection system with five lift stations, one main lift station, approximately 10,000 feet of 16-inch forcemain, and approximately 12,000 feet of 30-inch gravity outfall pipe. The four pond cells (two primary and two secondary) have a surface area of 20 acres each at the four-foot mean operating depth. The WWTF is designed to provide a total detention time of 193 days at design flow.


Wastewater influent is pumped from the City to the WWTF via the forcemain, where the flow is then diverted into the two primary cells for biological treatment to reduce biochemical oxygen demand (BOD) and total suspended solids (TSS). The wastewater is then moved from the two primary ponds to the two secondary pond cells for storage until discharge through controlled gates to the outfall pipe that goes to Pipestone Creek. Acceptable discharge periods for the controlled discharge are during April through June and September through December of each year. The WWTF includes a pretreatment facility to partially treat industrial-strength wastewater prior to entering the WWTF. The city-owned pretreatment facility pretreats industrial waste from Ellison Meats, a meat cutting and packaging facility in town, The pretreatment facility consists of a 13,000-gallon flow equalization tank, a 170,000-gallon aeration basin, 160,000 gallons of aerated sludge storage, a 20-foot diameter final clarifier, and chemical feed equipment to feed ferric chloride for the removal of phosphorus at the pretreatment facility. The pretreatment facility is designed to treat 30,000 gallons per day of industrial strength wastewater with a maximum 5-day BOD of 1,500 milligrams per liter (mg/L). The pretreated wastewater is routed to the City’s WWTF for final treatment. The City’s WWTF has been frequently receiving higher influent flows than the WWTF is designed to treat and store because of infiltration and inflow into the collection system. The higher flows have reduced the treatment and storage capacity of the WWTF, which has resulted in violations of National Pollutant Discharge Elimination System/State Disposal System (NPDES/SDS) Permit effluent limits, as well as the need to discharge wastewater outside of acceptable discharge periods. Consequently, the MPCA has placed a moratorium on the approval of sanitary sewer extension permits for the City. The MPCA required, and the City has completed, investigative evaluations and reports to document the sources of infiltration and inflow to the collection system and WWTF. The City has been working to address infiltration and inflow issues by replacing failing infrastructure in the collection system, fixing cross connections with the City’s storm sewers, identifying problem residential service connections, and eliminating sump pump and foundation drain discharges to the sewer collection system. Although there has been a reduction in infiltration and inflow and the City continues to test and fix problem areas in the collection system, the WWTF continues to be frequently hydraulically overloaded. In addition, the existing WWTF is unable to provide service for future growth of the City. Proposed Project The proposed Project will construct an additional 19-acre primary pond and a 19-acre primary/ secondary pond, along with associated piping, and will be located adjacent to the existing WWTF (see Figure 4). The additional ponds will increase the AWWF capacity of the WWTF to 0.930 mgd and provide a total detention time of 193 days at maximum design flow. This design flow will provide treatment capability and capacity for the City through the year 2030, based on the projected population and flow increases. Currently, wastewater is received at the WWTF from a forcemain into a below-grade structure, which diverts flow to the appropriate pond by manual operation of weir gates. The wastewater is proposed to flow to the ponds through an extension of the existing forcemain. The extended forcemain will diverge from the existing forcemain to a proposed control structure, which will direct flow by gravity to either of the proposed ponds. The two proposed ponds will operate in series with gravity flow to the existing site piping. The existing outfall pipe will continue to be used for discharging into Pipestone Creek. The two proposed ponds have been located to balance the earthwork required for the construction of the berms and pond floor.


The site where the proposed Project is located includes additional land to facilitate the construction of an additional stabilization pond in the future, if necessary. This additional pond cell is not expected to be needed or constructed for at least 20 years.

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 proposed Project is to alleviate the hydraulic overloading currently experienced at the existing WWTF in order to improve wastewater treatment service to the existing community, and to allow for future commercial, industrial, and residential development in the City. The Project will also include capacity for the discharge anticipated from the treatment process of a proposed community water treatment plant. The beneficiaries of the WWTF expansion include the citizens of Pipestone, who will have improved wastewater treatment service and will also have the opportunity to benefit from commercial and industrial expansion with supporting jobs critical to maintaining and growing the local economy. The expansion of the WWTF will facilitate growth of residential, commercial, and industrial industries that require sanitary sewer. The proposed Project is anticipated to be funded from a single source or combination of Public Facilities Authority (PFA) loans, U.S. Department of Agriculture (USDA) loans, and municipal bonds. The proposed Project has been placed on the 2010 PFA Intended Use Plan, and the city is currently working on completing the loan application. The City has also entered into discussions with USDA Rural Development regarding funding the proposed Project. Additionally, the City will be considering financing a percentage of the Project through municipal bonds. The capital costs of the Project will be recouped by user fees to the beneficiaries of the sanitary sewer system.

d. Are future stages of this development including development on any other property planned or likely

to happen? Yes No

If yes, briefly describe future stages, relationship to present project, timeline and plans for environmental review. The proposed Project includes additional area for the construction of another stabilization pond cell in the future, if needed. However, the addition of another stabilization pond cell is not expected to occur within the next 20 years.

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 proposed Project expands the original WWTF system that was constructed in 1989. Past environmental review occurred in 1986.


7. Project Magnitude Data Total Project Area (acres) 55.78 acres or Length (miles) NA Total Project Area (with existing facility) (acres)

210

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 -- If over 2 stories, compare to heights of nearby buildings -- 8. Permits and approvals required. List all known local, state and federal permits, approvals and

financial assistance for the project. Include modifications of any existing permits, governmental review of plans, and all direct and indirect forms of public financial assistance including bond guarantees, Tax Increment Financing and infrastructure. All of these final decisions are prohibited until all appropriate environmental review has been completed. See Minn. R. 4410.3100.

Unit of Government Type of Application Status Pipestone County Conditional Use Permit Pending EAW approval MPCA NPDES/SDS Surface Water Permit –

Modification Application Submitted

MPCA WWTF Facility Plan Technically approved

MPCA WWTF Plans and Specifications Submitted MPCA General NPDES/SDS Storm Water Permit

for Construction To be submitted

PFA (joint with MPCA) Application for State Revolving Loan Fund Program for Construction

To be submitted

DNR Water appropriation permit (for dewatering) To be submitted if applicable

Minnesota Department of Health

Monitoring Well Registration Submitted

USDA – Rural Development Rural Development Wastewater Funding 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 Project construction area is located south and adjacent to the existing WWTF. In the past, this land was used for agricultural row crop production. The primary row crops in the proposed Project area are corn and soybeans. Other crops grown in the area are wheat, oats, alfalfa, and other hay crops. The Project is not expected to have potential conflicts to the agricultural land surrounding the Project site. The Project area does not have any identified environmental hazards due to past uses. The Project will require site piping to cross an existing petroleum pipeline in accordance with the encroachment agreement and utility owner’s engineering review. The nearest residences to the facility are located 0.21 and 0.32 miles to the south.

10. Cover Types. Estimate the acreage of the site with each of the following cover types before and after

development: Before After Before After

Types 1-8 wetlands

0

0 Lawn/landscaping (riprap)

0

4.19

Wooded/forest 0 0 Impervious Surfaces 0 0 Brush/grassland 1.72 12.53 Stock pond 0.42 0 Cropland 53.64 0 Other (ww pond - floor) 0 37.17 Existing WWTF 154.22 154.22 Other (gravel road) 0 1.89 TOTAL 210 210

If before and after totals are not equal, explain why. The totals for before and after remain equal. The proposed infilling of a stock pond, located in the southwest corner of the proposed Project, will facilitate the construction of a pond berm. The stock pond, constructed in 1981, was designed to be filled with runoff from the adjacent drainage way. The local DNR conservation and zoning officers have been notified of the proposed infilling. A permit is not expected to be required for this work, but will be obtained if deemed necessary.

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. No adverse impacts to fish and wildlife resources and habitats on or near the site are expected from the proposed Project. The Project is located on what has been agricultural cropland.

Potential short-term adverse environmental impacts during construction include short-term localized erosion and airborne dust from the construction site from wind and water turbulence and heavy equipment use. Erosion and sediment control practices will include both temporary and permanent measures such as silt fence, erosion control barriers, seeding, riprap, and grading of properly sloped and seeded drainage ways.


The Project is being constructed to enable residential, commercial and other development in the community. To the extent that development increases, both the diversity and populations of wildlife species will tend to decline. Over the long term, indigenous wildlife throughout the service area will tend to be replaced by wildlife more typical of residential areas.

b. Are any state (endangered or threatened) species, rare plant communities or other sensitive

ecological resources on or near the site? Yes No

If yes, describe the resource and how it would be affected by the project. The city conducted a review of the DNR database information dated May 8, 2009 (Figure 3), which did not identify rare plants and animals, native plant communities, or other rare features located within or adjacent to the project limits. Pipestone County contains several species of plant life, insects, fish, and wildlife listed as either Endangered or Threatened in the State of Minnesota. The DNR also completed a review, dated November 18, 2009, of natural heritage information in the vicinity of the Project (see Figure 5). The review identified one fish species, Notropis topeka (Topeka shiner), on the Federal Endangered Species List that has been observed in the discharge stream, Pipestone Creek. The State of Minnesota lists the species as SPC (special concern). The USFWS, in a letter dated January 22, 2010 (see Figure 6), also discussed the Topeka shiner and recommended upstream and downstream monitoring to better understand the existing conditions within Pipestone Creek, as well as to develop baseline information to compare to future flow increases to potential impacts to the Topeka shiner. The USFWS does not believe that a Habitat Conservation Plan or an Incidental Take Permit would be necessary at this time. The proposed effluent limitations and monitoring requirements in the draft permit, based on water quality standards and effluent reviews, are considered protective for the Topeka shiner in Pipestone Creek. The ponds will not be permitted to be discharged when the receiving water is ice-covered, and the temperature of the proposed expanded discharge is expected to be the same as the ambient temperature in Pipestone Creek. The Project is expected to meet NPDES/SDS Permit effluent limits and be protective of the water quality standards for Pipestone Creek. The discharge is not expected to have a negative impact on the Topeka shiner. Other endangered or threatened species in Pipestone County would be outside of the Project area. The Project is proposed to be constructed from existing cropland and not expected to affect any species of concern.

Describe any measures that will be taken to minimize or avoid adverse impacts. Provide the

license agreement number (LA __________) and/or Division of Ecological Resources contact number (ERDB__#20100298____________) from which the data were obtained and attach the response letter from the DNR Division of Ecological Resources. Indicate if any additional survey work has been conducted within the site and describe the results.

Construction stormwater best management practices (BMPs) will be selected and used during construction of the additional pond cells to control sediment transport to Pipestone Creek. Erosion control will be required for excavated material and disturbed surfaces, and erosion control barriers will be installed around material piles and in drainage ways to capture sediment. Tracking control will be required for construction equipment exiting the site. Vegetative cover will be planted on earthen dikes surrounding the ponds to establish a natural cover. A dechlorination agent may be required if potable water is used for water balance testing and discharged into the receiving stream.


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 and give the DNR Public Waters Inventory (PWI) number(s) if the water resources affected are on the PWI. Not Applicable Describe alternatives considered and proposed mitigation measures to minimize impacts. The water resource to be affected is located in the same section of the proposed Project, Section 15, in Sweet Township, Pipestone County, T106N R46W. The water resource is a stock dugout that was constructed in 1981. It is intended to be filled to maximize the utilization of the Project area. The stock dugout is not identified on the Protected Waters and Wetlands Pipestone County-1983 inventory map.

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. The Project is proposed to include drain tile around the periphery of the additional cells to reduce hydrostatic pressure and insure the integrity of the pond liner. The drain tile will discharge into the perimeter ditch surrounding the existing stabilization ponds. The NPDES/SDS Permit will include monitoring of the drain tile discharge three times per year for fecal coliform, chlorides and conductivity. This is required to identify if there are leakage problems over time that may need to be addressed. Dewatering is anticipated during the installation of the drain tile at the appropriate depths. If required, a temporary dewatering permit will be obtained prior to construction activity. The construction of stabilization ponds requires a water balance to be performed. The water balance for the proposed Project is anticipated to utilize chlorinated wastewater from the existing stabilization ponds. The contractor may elect pursuing installation of a temporary well for purposes of obtaining water for the water balance. The contractor will be responsible for obtaining the necessary permits for drilling a temporary well prior to construction activity. No existing wells are located within the proposed project limits. A review of the Minnesota Department of Health on-line County Well Index does not identify any wells located in the same section as the proposed Project.

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

15. Water Surface Use. Will the project change the number or type of watercraft on any water body? Yes No


16. Erosion and Sedimentation. Give the acreage to be graded or excavated and the cubic yards of soil to be moved: 48.6 acres; 267,000 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. The dikes for the stabilization ponds will be constructed at a 3:1 horizontal to vertical slope. Dikes can be susceptible to erosion before completion of the Project. Erosion control will be required for both the dikes under construction as well as excavated material by installing erosion control barriers around material piles and in drainageways to capture silt in runoff. Erosion control BMPs include silt fence, erosion control blankets, wattles, tracking control, and re-establishment of vegetative cover over disturbed areas. Tracking control will be required for construction equipment exiting the site. Vegetative cover will be planted on berms to establish a natural cover. Dust control by chemical application will be required, if necessary. Erosion control devices such as silt fence and wattles will remain until all disturbed ground has established a vegetative cover.

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. The construction of the proposed Project is not anticipated to change the long-term quantity or quality of runoff from the site. The runoff from the site will most likely experience a short-term increase in turbidity during construction prior to the establishment of a vegetative cover for all disturbed areas; however, erosion control methods utilizing BMPs will be employed to minimize the effect of runoff to the extent possible. The Stormwater Pollution Prevention Plan, required as part of the construction stormwater permit, will identify the areas susceptible to erosion and illustrate the locations that will require the erosion control BMPs.

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 from the Project site currently follows the existing topography and collects in the Main-A branch of the man-made ditch flowing into Pipestone Creek, continues to Split Rock Creek and into the Big Sioux River. The proposed Project site is currently utilized for agricultural crop production and subject to erosion during periods when topsoil is not protected by crops. The majority of the Project site will be constructed into stabilization ponds and will retain precipitation within the perimeter. The remainder of the site to be disturbed will be seeded to vegetative cover to prevent erosion. The quality of runoff from the site is anticipated to improve in the long term because of the conversion of erosion-susceptible cropland to detention ponds and vegetation that minimizes erosion. The construction of the proposed Project is expected to decrease the turbidity of the runoff. The impact of runoff quality during construction activities is further mitigated since the Main A drainageway flows through a grassed waterway approximately one-half mile before leaving the site of the existing WWTF.


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

wastewater produced or treated at the site. The wastewater influent to the WWTF is normal domestic sewage and industrial wastewater following pretreatment. The following design characteristics were used for the proposed expansion: AWWF: 0.930 mgd BOD5 130 mg/L Equivalent Population 4,280

b. Describe waste treatment methods or pollution prevention efforts and give estimates of

composition after treatment. Identify receiving waters, including major downstream water bodies (identifying any impaired waters), 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 Project will expand the treatment capacity of the existing WWTF by constructing two additional wastewater stabilization ponds and associated piping. The WWTF is designed to reduce the solids and BOD of the wastewater through settling and decomposition by the bacteria within the facility. A stabilization pond system operates as a facultative pond with aerobic (oxygenated) or anaerobic (oxygen-depleted) conditions imposed by the changing of the seasons within the upper Midwest climate. The dissolved oxygen (DO) required by the bacteria is primarily supplied by the algae living within the pond. The quality of the monthly average effluent discharge to Pipestone Creek must be less than 25 mg/L of five-day carbonaceous BOD (CBOD5), 40 mg/L of TSS, and 200 fecal organisms per 100 milliliters (mL). In addition, the City has accepted a “freeze” on mass loading limits for CBOD5, TSS, and phosphorus based on the originally constructed facility’s design AWWF of 0.600 mgd for the WWTF in 1989. The proposed average monthly concentration discharge limits established by the MPCA for the draft NPDES/SDS Permit are: • 25 mg/L of CBOD5; • 45 mg/L of TSS • 200 organisms per 100 mL fecal coliform • 1 mg/L phosphorus during the months of May through September of each year. In addition, the City will be required to continue phosphorus monitoring of both the influent and effluent when a limit is not required. The City will also be required to monitor the wastewater effluent twice per year for ammonia nitrogen, total Kjeldahl nitrogen, nitrite/nitrate nitrogen, total residual chlorine, and total dissolved solids. The receiving body for the existing WWTF and proposed expansion is Pipestone Creek, which has been listed as an impaired water for fecal coliform and turbidity. The MPCA Pipestone Creek Fecal Coliform Bacteria and Turbidity Total Maximum Daily Load May 2008 Report (TMDL Report), approved by the U.S. Environmental Protection Agency (EPA) in July 2008, states that human sources in the watershed, including the City’s existing WWTF, as well as individual on-site


systems, contribute 0.4 percent of the total fecal coliform load in the watershed. The report also concluded that the City’s existing WWTF, with 23 TSS-related violations between 2001 and 2008, appeared to represent a small or moderate contribution of turbidity to Pipestone Creek during the facility’s discharge windows. The proposed Project is designed to increase treatment capacity and increases the detention time from 180 to 193 days at design flow, which increases the length of biological treatment. The TMDL Report (page 46) notes that population has declined, but that if there is an increase, revised permits may be sought. The TMDL Report also indicates the Project will not likely have a significant impact on Pipestone Creek, provided discharge limits are met, as the increased flow will add to the overall loading capacity of the system. As previously noted, the City has accepted a “freeze” or no increase to the existing mass loading limits for CBOD5 and TSS for the expanded WWTF. There will be no permitted increase in regulated pollutant loadings to the Pipestone Creek. The Project is designed to meet the NPDES/SDS Permit mass and concentration limits and not add to the impairment according to the TMDL Report and Implementation Plan approved by the MPCA in September 2008. Minn. R. 7053.0255, subp. 3.A.(3) states that:

“phosphorus removal to one milligram per liter is required when the discharge is new or expanded as defined in [Minn. R. 7053.0255] subpart 2, except when the discharger can demonstrate to the commissioner that the discharger qualifies for an alternative phosphorus limit as provided in [Minn. R. 7053.0255] subpart 4.”

The MPCA interprets this requirement as a year-round limit. The City submitted a request to the MPCA that the proposed Project qualify for an alternative seasonal 1.0 mg/L phosphorus effluent limit applicable during the months of May through September of each year. The MPCA effluent limits staff, after the review of the additional application materials for this alternative limit, has recommended the NPDES/SDS Permit MN0054801 for the proposed Project include the alternative limit. MPCA staff has also made the recommendation that the NPDES/SDS Permit for the proposed Project include a phosphorus mass limit of 1,989 kilograms per year (kg/yr), the existing mass loading in the discharge, to ensure that no new phosphorus is discharged to Pipestone Creek. The existing mass level of phosphorus is calculated at 1,989 kg/yr and was estimated by using the current AWWF of 0.6 mgd and 2.4 mg/L (the average of three complete years of phosphorus WWTF effluent data from 2006 through 2008). During the months the WWTF does not have a phosphorus effluent limit (October through April), the expanded WWTF (at full design flow of 0.93 mgd) will have to discharge phosphorus below a concentration of 1.55 mg/L to achieve compliance with the annual mass limit. The addition to the NPDES/SDS Permit of twice-per-year-monitoring requirements for effluent total residual chlorine, ammonia-nitrogen, total Kjeldahl nitrogen, nitrite/nitrate nitrogen, and total dissolved solids is now being required for municipal permittees. The MPCA will also require sampling for total residual chlorine in all dischargers to ensure compliance with toxicity rules/regulations. Federal regulations also require additional monitoring for the nitrogen series and total dissolved solids for surface discharging municipal WWTFs with a design flow of 0.100 mgd or more. All municipal pond WWTFs in Minnesota will be required to monitor once during the spring discharge and once during the fall discharge, if discharge occurs, throughout the five-year permit terms. These additional monitoring requirements are being added to permits as they are reissued or modified.


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.

19. Geologic hazards and soil conditions. a. Depth to ground water (from ground surface ) 2.1 feet minimum; 6.5 feet average

Depth to ground water (from pond floor) 3.1 feet minimum; 5.7 feet average Depth to bedrock (from ground surface) 390 feet within ½ mile 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. No geologic site hazards are expected based on information obtained from geotechnical exploration completed in April and May of 2009. The exploration was comprised of standard penetration test borings, test pits, and installation of groundwater monitoring wells. Previous experience working in the area and existing ponds construction documentation support an expectation of absences of geologic site hazards. Bedrock was not encountered with the borings to a depth of 26 feet below the surface. Review of boring logs for a residential well approximately ½-mile from the Project area recorded bedrock was encountered at depths of approximately 400 feet, which supports expectation of not encountering bedrock. A detailed site investigation was completed in May of 2009 to better characterize the subsurface conditions and determine the suitability of on-site material for construction of the Project. Nine standard penetration test borings were completed, along with permeability tests of site materials that were determined to have acceptable seepage requirements for use in building the clay liner. Additionally, three monitoring wells were installed to monitor the groundwater level. Currently all groundwater level recordings of the monitoring wells are approximately three feet below the proposed pond floor elevations. The proposed Project will include drain tile to intercept groundwater at an elevation of four feet below the pond floor elevation, in accordance with MPCA design criteria. A review of the Regional Hydrogeologic Assessment – Southwestern Minnesota, RHA-2 Plate 4 indicated that the sensitivity of surficial aquifers to pollution is moderate, taking years to decades for estimated travel time for waterborne surface contaminants to reach the ten-foot depth to groundwater table. This same review did not indicate that there were surface aquifers located in the Project area that would yield significant amounts of water.

b. Describe the soils on the site, giving Natural Resources Conservation Service classifications, if

known. Discuss soil texture and potential for ground-water contamination from wastes or chemicals spread or spilled onto the soils. Discuss any mitigation measures to prevent such contamination.

The proposed site consists of the approximate percentages of NRCS soil classifications determined from the NRCS on-line Web Soil Survey Application: J71A-Brookings silty clay loam – 34% J86B-Vienna silty clay loam – 5% J88B-Kranzburg silty clay loam – 22% J90B-Kranzburg Brookings complex – 13% J93A- Hidewood-Badger Complex – 26%


The preliminary site investigation determined the subsurface conditions encountered consisted of surface topsoil deposits underlain by clay till.

The proposed Project is located on the Sioux Quartzite Ridge in a moderately sensitive area of surficial aquifers risk to pollution with a time frame of years to decades before an aquifer could be contaminated by water-borne surface contaminants.1 According to hydraulic investigations from 1976, regional groundwater movement is in a southwesterly direction and shallow local groundwater movement is toward creeks and rivers.2 The proposed ponds will include a liner constructed from compacted clay material with low permeability. The pond liner construction will be closely monitored by an engineering materials testing agency to document the integrity of the liner. Mitigation measures to prevent groundwater contamination include performing a water balance study to confirm the integrity of the pond liner prior to operation. Additional measures include removing and rerouting any drain tiles located within the proposed site.

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.

Biosolids produced from the biological decomposition of the wastewater will settle to the bottom of the stabilization ponds. The summer climate’s increased sunlight and wave action convert the system to aerobic conditions to the depth of the sludge layer. The winter climate’s decreased availability of sunlight through ice converts the zone above the sludge layer to anaerobic conditions. The biological process of a stabilization pond converts organics within untreated wastewater into an algal mass. The algae will settle upon the bottom of the pond and form an anaerobic sludge layer. The sludge layer will fluctuate from a depth of approximately 6 inches in the summer to 2 feet in the winter with the increased depth due to the slowdown of biological processes from temperature and reduced light affects. The sludge accumulation in a stabilization pond system is balanced between growth of algae mass and anaerobic decomposition, and sludge removal is not required.

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.

The construction of the proposed Project will require the use of earthmoving equipment and portable generators. The equipment will utilize petroleum products including diesel fuel, grease lubricants, and oil. The contractor shall be responsible for utilizing practices to prevent spills and disposing of petroleum products in an approved manner.

1 Bradt, Randy. 1997. Regional Hydrogeologic Assessment Southwestern Minnesota. Surficial Hydrogeology. RHA – 2, Part B, Plate 3. 2 Anderson, H. W. Broussard, W. L. Farrell, D. F. Felsheim, P. E. 1976. Water Resources of The Rock River Watershed, Southwestern Minnesota. Water Quality at Base Flow. Hydrologic Investigations Atlas HA-555, Sheet 3.


The contractor may exercise the option of chlorinating wastewater from the existing stabilization ponds for performing the water balance. The disinfection agent typically utilized is sodium hypochlorite granules that can be hazardous to humans with direct exposure by contact or inhalation. The contractor will be responsible for the safety of workers handling chlorine chemicals, if utilized, and handling the materials properly to prevent direct contamination of surface water bodies.

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. There are no storage tanks on the site, except for the temporary use of portable fuel storage tanks for supporting earthmoving equipment. The contractor will be responsible for emergency response containment plans according to state regulations concerning petroleum products.

21. Traffic. Parking spaces added: -- Existing spaces (if project involves expansion): -- Estimated total average daily traffic generated: -- Estimated maximum peak hour traffic generated and time of occurrence: -- Indicate source of trip generation rates used in the estimates.

Vehicular traffic entering and leaving the site will be limited to WWTF operators and other approved personnel. The site access will be controlled by locked gates at the access roads and fences surrounding the additional proposed stabilization ponds. The WWTF operators typically make one trip a day to the site for daily rounds, plus occasional additional trips for composite sampling and discharging.

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. Traffic related to the operation of the proposed WWTF expansion will not increase vehicle-related emissions. Following completion of the proposed Project, the site will be visited at the same frequency as the existing WWTF; consequently, the Project will not cause a significant increase in air emissions.

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. The proposed Project does not include any stationary source emissions.

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. Equipment and construction activities will generate dust and noise during the construction of the proposed Project, which is expected to last approximately six months. Typical working hours will be Monday through Friday from 7:00 a.m. to 6:00 p.m. for construction. BMPs to reduce dust include minimizing disturbed areas by requiring equipment to remain on designated routes on site and when leaving the site. Other practices include using water to reduce dust generation. Dust control by chemical application will be required in the event that using water does not effectively reduce the dust. Concluding the earthwork construction, the site will be seeded to establish a vegetative cover and minimize wind erosion. The nearest residences to the construction location are located approximately .21 and .32 miles to the south. The intensity of the dust and noise impacts will depend upon the direction and intensity of prevailing winds. Odor Stabilization ponds may produce odors for a small period of time (2-10 days) in the spring when the system changes from anaerobic conditions to aerobic conditions. Pond turnover occurs when the ice thaws from the pond and releases hydrogen sulfide produced during anaerobic conditions. The operation of the ponds in series prior to the turnover period will minimize the organic loading rates and is expected to subsequently reduce nuisance odors. Residences downwind of the stabilization ponds may experience brief periods of nuisance odors, which will dissipate with the completion of pond turnover.

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 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 approval of a Pipestone County Conditional Use Permit. A public hearing will be held concerning the issuance of the permit. The public hearing will occur following the completion of the EAW process. Concerns about nuisance odors have been expressed in the past; however, the completion of a pretreatment facility in April 2005 has greatly reduced the occurrence of odors. Odor reduction measures include operating the ponds in series to reduce the organic loading rates and subsequently reduce nuisance odors. Concerns identified during the public hearing process will be reviewed and addressed with the goal to create an informed consensus coinciding with the Project’s objectives.

The eastern end of the Project is currently zoned for urban expansion as per the County zoning map. The City will work with the County to ensure all applicable re-zoning requirements are met.


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.) The construction of access roads around the perimeter of the proposed ponds will be required for operators to conduct daily inspections of the ponds. The access road will be controlled by gates to allow only access for operators and other approved personnel.

29. Cumulative potential effects. 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 potential effects. (Such future projects would be those that are actually planned or for which a basis of expectation has been laid.) Describe the nature of the cumulative potential effects and summarize any other available information relevant to determining whether there is potential for significant environmental effects due to these cumulative effects (or discuss each cumulative effect under appropriate item(s) elsewhere on this form).

Water Quality The proposed expansion of the WWTF has been evaluated in conjunction with the Pipestone Creek Fecal Coliform Bacteria and Turbidity TMDL. The existing WWTF is included in the waste load allocation for the TMDL. Although the proposed expansion of the WWTF will allow for an increase in flows as a result of growth in the City, the proposed expansion of the WWTF is required and designed to treat to the level necessary to meet the existing mass effluent limits for CBOD5 and TSS, as well as to continue to treat to the secondary treatment effluent limit for fecal coliform. The proposed expansion to the WWTF will continue to have controlled discharges to the Pipestone Creek and is designed to allow for additional detention time so that the controlled discharges will take place during periods of the year (April 1 through June 15, and September 15 through December 15) when flow and temperature conditions in Pipestone Creek are most conducive to assimilation of a discharge. Growth and Development Future residential, commercial, and other types of development within the City will be enabled as a result of the Project. Future development will be accompanied by increased traffic, stormwater runoff, and solid waste generation. As residential and commercial areas expand, the amount of farmland, open space, and wildlife habitat in the area will also decrease. The City will need to regularly assess and address impacts that occur due to the development.

The growth and development that would be enabled by this Project would cause increases in impervious surfaces in the surface area. Substantial increases in impervious surfaces could result in an increase in the amount of precipitation that would run off into surface waters. Precipitation will remove nutrients from the air as it falls. Stormwater runoff transport these nutrients and numerous other pollutants, such as sediment, oil, grease, heavy metals, salt, etc., to surface water, causing degradation of water quality and aquatic habitats. Runoff may also cause erosion as it flows over the ground, entraining phosphorus and sediment and resulting in nutrients and sediment entering surface water, to the detriment of water quality. Stormwater and pollutant loading from the City were addressed in the TMDL Report and Implementation Plan.

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605-692-6342www.bannerassociates.com

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LEGEND:MCBS SITES OF BIODIVERSITY SIGNIFICANCEMCBS NATIONAL WETLANDS INVENTORYMCBS NATIVE PLANT COMMUNITIESSTREAMSPROJECT LIMITSSECTION 15 T106N R46W SWEET TOWNSHIPEXISTING WWTF

PROJECTLOCATION

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"Data included here were provided by the Division ofEcological Resources, Minnesota Department of NaturalResources (DNR), and were current as of (5-08-09). Thesedata are not based on an exhaustive inventory of the state.The lack of data for any geographic area shall not beconstrued to mean that no significant features are present."

Copyright 2007 State of Minnesota, Department of NaturalResources

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SECTION 15 T106N R46W, SWEET TOWNSHIP, PIPESTONE COUNTY, MINNESOTA

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DNR Information: 651-296-6157 ● 1-888-646-6367 ● TTY: 651-296-5484 ● 1-800-657-3929

An Equal Opportunity Employer Who Values Diversity

Phone: (651) 259-5109 Fax: (651) 296-1811 E-mail: [email protected] November 18, 2009 Correspondence # ERDB 20100298 Lance Weatherly Banner Associates, Inc. 2307 W 57th Street, Suite 102 Sioux Falls, SD 57108 RE: Natural Heritage information in the vicinity of the proposed Pipestone WWTF Expansion, T106N R46W Section 15, Pipestone County Dear Mr. Weatherly,

As requested, the Minnesota Natural Heritage Information System has been queried to determine if any rare species or other significant natural features are known to occur within an approximate one-mile radius of the proposed project. Based on this query, rare features have been documented within the search area (for details, see the enclosed database reports; please visit the Rare Species Guide at http://www.dnr.state.mn.us/rsg/index.html for more information on the biology, habitat use, and conservation measures of these rare species). Please note that the following rare features may be impacted by the proposed project:

• Pipestone Creek is federally designated as critical habitat for the Topeka shiner (Notropis topeka), a federally listed endangered and state-listed special concern fish species. Topeka shiners are adversely impacted by actions that alter stream hydrology or decrease water quality, including sedimentation, eutrophication, and pollution/contamination. Whether the project as proposed has the potential to impact Topeka shiners needs to be determined. The determination, its justification, and any proposed mitigation/avoidance measures should be addressed in section 11b of the EAW. Given the federal status of this species, I also recommend that you coordinate with the U.S. Fish & Wildlife Service’s Twin Cities Field Office (612-725-3548) regarding this project.

The Natural Heritage Information System (NHIS), a collection of databases that contains information

about Minnesota’s rare natural features, is maintained by the Division of Ecological Resources, Department of Natural Resources. The NHIS is continually updated as new information becomes available, and is the most complete source of data on Minnesota's rare or otherwise significant species, native plant communities, and other natural features. However, the NHIS is not an exhaustive inventory and thus does not represent all of the occurrences of rare features within the state. Therefore, ecologically significant features for which we have no records may exist within the project area.

The enclosed results include an Index Report of records in the Rare Features Database, the main database of the NHIS. This report is copyrighted, but may be reprinted, unaltered, in the EAW. If you wish to reproduce the index report for any other purpose, please contact me to request written permission.

This letter does not constitute review or approval by the Department of Natural Resources as a whole. Instead, it identifies issues regarding known occurrences of rare features and potential effects to these rare features. Additional rare features for which we have no data may be present in the project area, or there may be other natural resource concerns associated with the proposed project. For these concerns, please contact

Minnesota Department of Natural Resources

500 Lafayette Road

St. Paul, Minnesota 55155-4025

Division of Ecological Resources, Box 25

Figure 5A

your DNR Regional Environmental Assessment Ecologist, Kevin Mixon, at 507-359-6073. Please be aware that additional site assessments or review may be required.

Thank you for consulting us on this matter, and for your interest in preserving Minnesota's rare natural resources. An invoice will be mailed to you under separate cover. Sincerely,

Lisa Joyal Endangered Species Environmental Review Coordinator enc. Rare Features Database: Index Report Rare Features Database: Detail Report Rare Features Database Reports: An Explanation of Fields cc: Randall Doneen

of 1Minnesota Natural Heritage Information SystemIndex Report of records within 1 mile radius of:ERDB #20100298 - Pipestone WWTF Expansion

T106N R46W Section 15Pipestone County

Printed November 2009 Data valid for one year

Rare Features Database:EO ID #

Last Observed Date

GlobalRank

StateRank

MNStatus

FederalStatusElement Name and Occurrence Number

Vertebrate Animal

S3 G5 1949-06-30Mustela nivalis (Least Weasel) #13 SPCT106N R46W S14, T106N R45W S18, T106N R46W S11, T106N R45W S7, T [...] ; Pipestone County

30827

S3 G3 2007-05-(21 or 22 or 23)

LENotropis topeka (Topeka Shiner) #61 SPCT106N R47W S13, T106N R46W S5, T106N R46W S8, T106N R46W S7, T [...] ; Pipestone County

25636

Invertebrate Animal

S3 G2G3 1965-07-10Oarisma powesheik (Powesheik Skipper) #8 SPCT106N R46W S23, T106N R46W S13, T106N R46W S25, T106N R46W S24, T [...] ; Pipestone County

2678

S3 GNR 1967-07-10Phidippus pius (A Jumping Spider) #4 SPCT106N R46W S23, T106N R46W S13, T106N R46W S24, T106N R46W S14 ; Pipestone County

27640

S3 G3 1969-08-30Speyeria idalia (Regal Fritillary) #91 SPCT106N R46W S13, T106N R46W S25, T106N R46W S24, T106N R46W S26, T [...] ; Pipestone County

23596

Records Printed = 5 Minnesota's endangered species law (Minnesota Statutes, section 84.0895) and associated rules (Minnesota Rules, part 6212.1800 to 6212.2300 and 6134) prohibit the taking of threatened or endangered species without a permit. For plants, taking includes digging or destroying. For animals, taking includes pursuing, capturing, or killing.

Copyright 2009, Division of Ecological Resources, State of Minnesota DNR

Figure 5B

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pipestone wwtf expansion environmental assessment worksheet · note to reviewers: the environmental...

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