STATE OF MINNESOTA MINNESOTA POLLUTION CONTROL AGENCY

Transcription

1 STATE OF MINNESOTA MINNESOTA POLLUTION CONTROL AGENCY In the Matter of the Decision on the Need for an Environmental Impact Statement for the Proposed South Washington County Wastewater Treatment Plant FINDINGS OF FACT AND CONCLUSIONS The Metropolitan Council Environmental Service Wastewater Services Department (MCES/WWS) is proposing to phase out the existing wastewater treatment plant (WWTP) that serves Cottage Grove. The 10 acre site will be used for construction of a new 10 million gallon per day (MGD) WWTP to provide wastewater treatment capacity to the design year 2020 for a service area including Cottage Grove, the eastern portion of Woodbury, and potentially, southern Lake Elmo. The Minnesota Pollution Control Agency (MPCA) staff prepared an Environmental Assessment Worksheet (EAW) for the project, and received ten letters of comment from agencies, organizations, and individuals. After reviewing the comments, the EAW, and other information relevant to the project, including mitigative measures that have been incorporated into the design and permits for the proposed project, the staff has concluded that the project would not have the potential for significant environmental effects. Based on this record, the MPCA hereby makes the following Findings of Fact and Conclusions, signifying that the preparation of an Environmental Impact Statement (EIS) is not warranted. I. PROJECT DESCRIPTION A. Project Proposal. FINDINGS OF FACT The MCES/WWS is proposing to phase out the existing WWTP that serves Cottage Grove. The acre site would be used for construction of a new 10 MGD (average annual flow) WWTP to provide wastewater treatment capacity to the design year 2020 for a service area including Cottage Grove, the eastern portion of Woodbury, and, potentially, southern Lake Elmo. The proposed facility is the first WWTP to be built using the design-build approach as compared to the traditional design-bid-build approach to facility construction. In the latter, a facility is designed, the design is subjected to the environmental review and permitting processes, then the job is bid and the facility is constructed. In design-build a basic design concept and performance requirement is advertised and the contractor bids on finalization of the design and construction. The exact details of the project will be refined as the design/build process is completed. The practical result of the difference is that some elements of the project may change between environmental review and permitting and the actual construction. The challenge is to provide sufficient specificity about what the project nature and effects in the environmental review and permitting processes that the full nature of alternatives in design may be anticipated. Revisions to the project that would deviate substantively from the project description in the EAW and/or permit would require preparation of a revised or amended EAW. The basic design concept for this project provides for construction of retaining walls, pumps, screens, grit tanks, primary clarifiers, secondary clarifiers, and facilities for activated sludge treatment with ammonia nitrogen removal and phosphorus removal and for ultraviolet light disinfection of effluent. This construction would be staged on the existing site. The existing plant would be demolished as the new facilities are completed. A new outfall pipe and supporting structures would be built using TDD (for hearing and speech impaired only): (651) Printed on recycled paper containing at least 10% fibers from paper recycled by consumers

2 tunneling or some other technique under the bluff that would not disturb the surface. The MCES/WWS will also evaluate renovation of the existing outfall where it descends the bluff. A new river outfall line will be constructed from the bluff to a new outfall structure near or south of the Freeborn Island Light and Daymark near the Mississippi River Navigation Channel. The construction methods for this outfall line will be decided by the bidding contractor, and is anticipated to be dredged excavation and backfill. It will be subject to oversight of the Minnesota Department of Natural Resources (MDNR), the US Army Corps of Engineers, and the US Fish and Wildlife Service. The MCES/WWS is requesting a permitted annual average flow of 10 MGD and an average wet weather flow of 11.9 MGD. Effluent limits will be as follows: CBOD 5 (5-day carbonaceous biochemical oxygen demand): Winter Summer TSS (total suspended solids) Ammonia (NH 3 ) (summertime only) Phosphorus (P) (annual average) Dissolved Oxygen (DO) 25 mg/l 10 mg/l 30 mg/l 5 mg/l 1 mg/l 6 mg/l The facility will have the capability to accommodate a future expansion to provide 5-MGD additional treatment capacity. Separate environmental review and permit action would be required for such expansion. B. Project Site. The site is the location of the existing Cottage Grove WWTP. There are areas on site that have been filled or excavated to allow construction of the facility. The site is partially wooded, and there is about forty feet of topographic relief on the 10.7-acre parcel. There are no known environmental hazards present on site. The site is located atop the Mississippi River bluffs at the southern boundary of the city of Cottage Grove. At the base of the bluffs, next to the Mississippi River, are the tracks of the Burlington Northern and Santa Fe Railroad Company. Immediately to the south is the Mississippi River, which at this point is about 0.8 miles in width. To the east of the facility, a wooded ravine separates the facility from the 3M Cottage Grove industrial complex. To the west is agricultural or open land owned by 3M. II. PROJECT HISTORY A. The project entails the construction of a new municipal wastewater treatment system with an average wet weather design flow capacity of 11.9 MGD. The preparation of an EAW was mandatory pursuant to Minn. R , subp. 18.B, which establishes a minimum threshold of 50,000 gallons per day for EAW preparation. B. An EAW was prepared on the proposed project and distributed to the Environmental Quality Board mailing list and other interested parties on April 2, C. A press release containing the notice of availability of the EAW for public review was provided to media serving the project area on April 2, D. The public comment period for the EAW began on April 5, 1999, and ended on May 5,

3 Comment letters were received from: the Minnesota Historical Society (MHS), the National Park Service, (NPS), the City of Cottage Grove Advisory Committee on Historic Preservation, the MDNR, the Washington County Office of Administration, the City of Cottage Grove Community Development Director, the Minnesota Department of Transportation, the Minnesota Department of Health, (MDH), the MCES, Environmental Planning and Evaluation Department.(EPE). the MHS (second letter). These comment letters are attached to these Findings, as are the MPCA responses to comments. Both are hereby incorporated by reference. E. Subsequent to the end of the public comment period, MCES/WWS requested that a clarification be provided as to permit conditions applicable to the facility. MCES/WWS also requested that the project description be revised to allow them to study the feasibility of renovating the existing outfall line. Since the MPCA staff believed that these changes, while substantive, would not result in significant environmental impacts, a letter was sent to all recipients of the original EAW describing the changes and the reasons why the MPCA deemed them not to be significant. The letter requested any individuals desiring a full thirty-day comment period extension to make such a request by FAX, e- mail, or telephone to Eric Kilberg, the Environmental Review Project Manager. No such requests were received as of July 8, III. CRITERIA FOR DETERMINING THE POTENTIAL FOR SIGNIFICANT ENVIRONMENTAL EFFECTS In deciding whether the project has the potential to result in significant environmental effects, the MPCA considered the four criteria set forth in Minn. R , subp. 7. These criteria are: A) the type, extent, and reversibility of environmental effects; B) cumulative potential effects of related or anticipated future projects; C) the extent to which the environmental effects are subject to mitigation by ongoing public regulatory authority; and D) the extent to which environmental effects can be anticipated and controlled as a result of other available environmental studies undertaken by public agencies or the project proposer, including other Environmental Impact Statement s (EISs). The MPCA findings with respect to each of these criteria are set forth below

4 A. TYPE, EXTENT, AND REVERSIBILITY OF ENVIRONMENTAL EFFECTS 1. Potential impacts on water quality of the Mississippi River: Use Classifications and Standards. The proposed facility will discharge directly to the Hastings dam (U.S. Army Corps of Engineers Lock and Dam Number 2) pool on the Mississippi River. This reach of the Mississippi River is not a listed water in Minn. R., pt , subp. 4 (the list of classified waters in the Upper Mississippi River drainage basin). Under Minn. R. pt unlisted waters are assigned water use classifications of 2B (Aquatic Life and Recreation), 3B (Industrial Consumption), 4A (Crop Irrigation), 4B (Livestock and Wildlife Watering), 5 (Aesthetic Enjoyment and Navigation), and 6 (Other Uses) waters. The principal water quality standards associated with these use classifications are: 40 μg/l of un-ionized NH 3 as nitrogen, a ph range of 6.5 to 9.0, and a fecal coliform level not exceeding 200 organisms per 100 ml. There is also a special DO standard for this reach (between the outlet of the Metropolitan Wastewater Treatment Plant near Pigs Eye Lake to Lock and Dam Number 2 at Hastings) of the Mississippi River. Other Class 2B waters have a DO standard of 5 milligrams per liter (mg/l) as a daily minimum. In this reach, the DO standard is not less than 5 mg/l as a daily average, from April 1 to November 30, and not less than 4 mg/l at other times. The MCES evaluated the impacts on river DO of the CBOD 5 loading from the proposed discharge using the computer model AESOP and 1981 data. The Council and the MPCA agree on reaction rates and coefficients to be used in the AESOP model. The load from the Cottage Grove treatment plant was doubled and tripled, in successive model runs. The wastewater loads from the other dischargers were unchanged. The simulation showed that the river's DO would only decrease a few hundredths of a mg/l. MPCA Staff evaluated the discharge using the computer model WASP and 1994 data, with similar results. The DO water quality standard would therefore be protected. Impacts on the NH 3 water quality standard are not expected for two reasons. First, an effluent NH 3 limit of 5 mg/l will apply to the facility during summer months, when aquatic biota is most sensitive to the pollutant. Second, the effluent discharge location is being moved to the edge of the navigation channel to obtain better mixing with river water. The University of Minnesota St. Anthony Falls Laboratory predicted mixing effects would produce a ten-fold dilution of the initial effluent concentration within 100 meters of downstream travel. The analysis was completed for low flow conditions (7Q10-1,430 cubic feet per second). The facility does not presently have an effluent ammonia limit, but the ammonia concentration of the present discharge averages 4.1 mg/l. Phosphorus is a pollutant that is significant to long-term water quality in the Mississippi, and that has been a major issue in several recent EAWs. Phosphorus has historically been unregulated in most permits - effluent limits have not been assigned in the past, unless the discharge has been located within 50 miles of a lake or reservoir. This is because only recently has it become clear that phosphorus can cause water quality impacts in rivers. Consequently, when applying the nondegradation requirements of Minn. R (Nondegradation for all waters) for phosphorus for any given discharge, there is no previous effluent concentration or baseline data on which to base the evaluation of whether phosphorus loading will increase. Concerns have been expressed about the impacts of phosphorus in downstream lakes such as Lake Pepin and on in-stream water quality in the Mississippi. These concerns have prompted the MDNR and some environmentalist organizations to request that permit effluent limits for several facilities include - 4 -

5 limits on phosphorus concentration, usually 1 mg/l, or annual mass limits based on no net increase over historical discharges. While this appears to be a prudent conservative strategy, MPCA staff has not presently taken a position in favor of mandatory mass limit caps or concentration limits. Basin management is the main policy context for implementation of the phosphorus strategy. The MPCA Phosphorus Strategy emphasizes the gathering of data on instream phosphorus and a strong reliance on partnership and nonregulatory solutions until such time as the scientific basis for new regulatory approaches is established. These nonregulatory solutions have included several recent permits where permittees have agreed to voluntary effluent phosphorus mass limit caps or concentration limits. MCES/WWS proposed a 1-mg/L annual average effluent phosphorus limit using a biological removal concept. This is as rigorous a limit for phosphorus as has been applied to the vast majority of dischargers in the Upper Mississippi Basin. In summary, the proposed 10 mg/l CBOD 5 summertime limit will protect water quality standards for DO and ammonia. The 1-mg/L voluntary effluent phosphorus limit accepted by the MCES/WWS will assure that the facility does not contribute to the problem of potential cumulative impacts of phosphorus. 3 Impacts on Threatened Species. No threatened or endangered species, or their habitat, are known to exist on the site. There is the possibility that state-listed and/or federal-listed endangered or threatened species of mussels may exist in the area where the outfall line will be constructed. If excavation and backfill were used as the outfall construction technique, then state and federal mussel taking permits would be required, followed by a survey for the mussels and subsequent relocation thereof. Alternative methods of construction may obviate a taking permit, survey and relocation. 4. Consistency with the Mississippi River Corridor Critical Area and the Mississippi National River Recreation Area (MNRRA) Comprehensive Management Plan (CMP). The facility is required by the Critical Areas Act to comply with the Critical Areas standards and guidelines, now administered by the MDNR. The city of Cottage Grove requires a conditional use permit (CUP) which also must comply with these standards and guidelines. Because the project will be procured using designbuild methods, many of the details that are subject to these standards and guidelines have yet to be determined. Such details include grading, fill removal, slope stabilization, tree removal and replacement, and restoration of natural vegetation. The City, the MDNR, the NPS, and the MCAE/EPE have expressed concern that the design-build approach means that the details of the plan will not be finalized before the resolution of environmental review. A process exists to resolve this issue, as follows: The detailed plans will be completed by the design-build contractor, who will be selected by MCES/WWS on the basis of that contractor s proposal in response to a Request for Proposals (RFP) prepared by the MCES/WWS. Part of that request for proposals is a description of the Critical Areas standards and guidelines. The RFP will be provided to the interested agencies for a thirty-day review. If necessary, the RFP may be changed by addendum. When detailed plans have been developed, they will be provided for thirty day s review to the City, the NPS, the MPCA, the MDNR and the MCES/EPE. The process is described in an August 25, 1999 letter from Rebecca Flood, a copy of which is attached and incorporated into these Findings. Compliance with the NPS MNRRA CMP is voluntary, however, MCES has indicated that maximum possible compliance will be attempted

6 5. Erosion and Sedimentation during construction. The facility will be subject to the National Pollution Discharge Elimination System (NPDES) Stormwater General Permit for construction. That general permit requires that best management practices be employed to minimize erosion and off-site transport of sediment. Erosion control is also the subject of ongoing discussions between MCES/WWS and MDNR. 6. Post-construction Stormwater Runoff from the Project. Stormwater from the plant and environs will be collected and either introduced into the treatment facility or provided separate treatment before discharge to the Mississippi River via the plant s outfall structure. No adverse impact on Mississippi River water quality is expected. 7. Stationary Source Air Emissions. A back-up power source will be required for the facility, since Northern States Power Company has advised the MCES that the existing grid cannot provide a redundant power line. A backup generator will be constructed that may be used in an Energy Service Rider, where power is generated on-site during peak demand. The generator necessary for this may require an emission facility permit from MPCA. 8. Odors, Noise and Dust. The construction of the WWTP will result in some equipment noise and some minimal generation of dust. Nearest residential receptors are 3600 feet distant. The new facility will have an odor treatment capability. 9. Impacts on Scenic Views and Vistas. Executive Order 79-19, requires a minimal impact on the view of and from the Mississippi River. Consistency with the Executive Order and the Critical Areas requirements will be addressed as part of the review by the MDNR, NPS, and MCES/EPE as well as the Cottage Grove conditional use permit process, which will include public review and comment. The CUP will include a requirement for replacement of trees that are removed. 10. Cumulative Impacts. The project is in response to the area s and cities planned growth. It enables substantial residential, commercial, and other development in the cities of Cottage Grove, Woodbury, and possibly Lake Elmo. Such development will result in increased demand on existing infrastructure and the construction of new infrastructure such as utilities, roadways, fire and police, and schools. It will also result in increased impervious surfaces and traffic, which in turn may result in polluted runoff, diminished air quality and increased noise. It is the responsibility of local community and regional planning to apply necessary controls to assure that the enabled development does not result in significant environmental effects. B. CUMULATIVE POTENTIAL EFFECTS OF RELATED OR ANTICIPATED FUTURE PROJECTS 1. The discharge of treated wastewater from this facility is one of several sources of NH 3 and CBOD 5 loading to the Mississippi River. These nutrients can directly impact DO in the river, and the proposed NPDES permit for the facility includes a summertime 10 mg/l effluent CBOD 5 and a summertime 5 mg/l NH 3 limit to protect the DO standard which applies to this reach of the Mississippi. That river DO standard is not less than 5 mg/l as a daily average, from April 1 to November 30, and not less than 4 mg/l at other times. 2. Together with other existing facilities in the Upper Mississippi River Basin, this facility will be a source of phosphorus entering the Mississippi River. The projected phosphorus loading from the proposed facility at a permitted average wet weather flow of 11.9 MGD and an effluent phosphorus concentration of 1 mg/l is about 45 kg/day. The estimated phosphorus from the existing facility at average wet weather flow of 3.18, and average measured effluent phosphorus concentration of 4.2 is 51 kg/day. The MDNR and some environmental groups have - 6 -

7 recommended that, until these data are collected, subsequent dischargers should be assigned 1 mg/l effluent phosphorus concentration limits. The voluntary acceptance of a year-round effluent phosphorus limit of 1 mg/l by the MCES/WWS is consistent with this recommendation. 3. Development enabled by the project, over the long term, could result in conversion of farmland and open land to residential and commercial development with an attendant increase in impervious surfaces and stormwater runoff, which could contain nutrients and other contaminants that could impact surface water quality. C. THE EXTENT TO WHICH THE ENVIRONMENTAL EFFECTS ARE SUBJECT TO MITIGATION BY ONGOING PUBLIC REGULATORY AUTHORITY 1. The following permits or approvals will be required for the project: Unit of Government Permit or Approval Required a. US Fish and Wildlife Service (FWLS) Shellfish Taking Permit b. US Army Corps of Engineers (COE) Section 10 Permit for activities affecting navigable waters of U.S. c. COE Section 404 General Permit for dredging and filling in navigable waters d. MPCA Section 401 Water Quality Certification of COE Section 404 Permit e. MPCA NPDES Permit for a discharge to receiving waters f. MPCA NPDES General Stormwater Construction Permit for construction that will disturb more than 5 acres of vegetative cover g. MPCA Facility Plan Review and Approval h. MPCA Plans and Specifications Review and Approval i. MPCA Air Emission Facility Permit (may be required) j. MDNR Protected Waters Permit k. MDNR Shellfish Survey & Taking l. MDNR Critical Areas Review m. MDH Plumbing Plan Review n. MDH Possible Variance from Well Code o. National Park Service MNRRA Review p. MCES Environmental Planning & Evaluation Critical Areas Review q. City of Cottage Grove CUP r. City of Cottage Grove Detailed Site Plan Approval - 7 -

8 2. Description of the Scope of Key Permits/Approvals: a. US FWLS, Shellfish Taking permit. Controls the relocation of any shellfish found during the shellfish survey. b. COE. Section 10 Permit for activities affecting navigable waters of U.S. This permit regulates the construction of the outfall line and structure. c COE. 404 Dredge and Fill nationwide permit 12. The COE regulates the excavation in wetlands and placement of excavated materials. d. MPCA. The 401 Certification of the 404 Dredge and Fill Permit. The MPCA certifies that water quality impacts will not result from activities permitted under the Section 404 permit issued by the COE. e MPCA. NPDES permit for the construction and operation of the wastewater treatment facility. The NPDES permit stipulates the maximum discharge flow and pollutant loading allowed from the facility. f. MPCA. The NPDES general storm water permit. Soil will be disturbed during construction. This general permit requires the use of silt fences, bale checks, and prompt revegetation to prevent eroded sediment from leaving the construction site. g. MPCA. The Facility Plan Review assures the facility meets minimum engineering standards. h. MPCA. The Plans and Specifications Review and Approval assure the facility meets minimum engineering standards. i. MPCA. The Air Emission Facility Permit, if required, would assure that the standby power generator is compliant with the Clean Air Act. j MDNR. Protected Waters Permit for construction of the outfall line and structure in the Mississippi River k. MDNR. The Shellfish Survey & Taking Permit will regulate the survey and relocation of freshwater mussels in the area of the outfall line, if needed. l. MDNR. The MDNR has responsibility for implementing the Critical Areas Act. It reviews the MCES/WWS proposal to assure consistency with the Critical Areas standards and guidelines. It will also review the Cottage Grove CUP, the RFP, and the Detailed Site Plan for compliance with those standards and guidelines. m. MDH. The Plumbing Plan Review assures the facility will comply with the State Plumbing Code. n. MDH. The variance from the State Well Code assures that the integrity of the potable water well and its supplying aquifer is protected. o. NPS; MNRRA Review. The NPS will work with the Metropolitan Council to assure that - 8 -

9 the proposed facility is as consistent as possible with the voluntary policies in the MNRRA CMP. The NPS will also be provided with copies of the RFP and the Detailed Site Plans and may provide input to the MCES/WWS and the City regarding consistency with the MNRRA CMP. p. Metropolitan Council: Critical Areas Review. The MCES/EPE will review the CUP application, the RFP, and the Detailed Site Plans to assure that the proposal is consistent with Critical Areas standards and guidelines. q. City of Cottage Grove CUP. This permit is the main vehicle for assuring compliance with the Critical Areas standards and guidelines. MCES/WWS is submitting a conditional use permit application to the City. This application includes an Executive Summary of the Natural Resources Restoration Plan. The complete application will be subjected to review and comments by the MDNR, the MCES/EPE, and the NPS and will be available for public review. These comments will be addressed by the project proposer and incorporated into the final Natural Resources Restoration Plan and the CUP r. City of Cottage Grove. Detailed Site Plan Approval. After the CUP is approved, the MCES/WWS will issue an RFP for the design-build of the facility. (This RFP will be submitted to interested agencies, including the City, for review and comment.) Based on the RFP, the design-build contractor will prepare a Detailed Site Plan, which will be submitted to the City and interested agencies for review and comment, and city approval. 3. The MPCA finds that the potential environmental effects of the project are subject to mitigation by ongoing public regulatory authority. D. THE EXTENT TO WHICH ENVIRONMENTAL EFFECTS CAN BE ANTICIPATED AND CONTROLLED AS A RESULT OF OTHER AVAILABLE ENVIRONMENTAL STUDIES UNDERTAKEN BY PUBLIC AGENCIES OR THE PROJECT PROPOSER, INCLUDING OTHER EISs. 1. The proposed WWTP improvements have been reviewed by MPCA staff, as well as the MHS, the NPS, the city of Cottage Grove, the MDNR, the Washington County Office of Administration, the MDH, and the MCES/EPE. None of these commentors requested an EIS. 2. There are no elements of the project that pose the potential for significant environmental effects, which cannot be, addressed in the project design and permit development processes. 3. The MPCA finds that the environmental effects of the project can be anticipated and controlled as a result of environmental review, previous environmental studies, and permitting processes undertaken by the MPCA on similar projects

10 CONCLUSIONS 1. The EAW process, the permit development process, the facility planning process, and responses prepared by MPCA staff in response to comments on the EAW, have generated information adequate to determine whether the potential environmental effects of the project are significant. 2. Areas where the potential for significant environmental effects may have existed have been identified and appropriate mitigative measures have been incorporated into the project design and permits. The project is expected to comply with all MPCA standards. 3. Based on the criteria established in Minn. R , the project does not have the potential for significant environmental effects. 4. An Environmental Impact Statement on the proposed South Washington County Wastewater Treatment Plant, proposed by the Metropolitan Council, Environmental Services Division, Wastewater Services Department, is not required. 5. Any findings that might properly be termed conclusions and any conclusions that might properly be termed findings are hereby adopted as such. Karen A. Studders, Commissioner Minnesota Pollution Control Agency Date

11 RESPONSE TO COMMENTS SOUTH WASHINGTON COUNTY WASTE WATER TREATMENT PLANT (WWTP) ENVIRONMENTAL ASSESSMENT WORKSHEET (EAW) Dennis A. Gimmestad, Government Programs and Compliance Officer, State Historic Preservation Office, Minnesota Historical Society (MHS): Letter dated April 21, COMMENT 1: Mr. Gimmestad noted that the response to Question 26a in the EAW makes reference to an archaeological survey/assessment of the area that was completed by BRW, Inc. He indicated that, in order for the MHS to comment on the issue, they needed to review a copy of the report. RESPONSE: Comment noted. Craig Christenson of the Metropolitan Council Environmental Services, Wastewater Services Department (MCES/WWS) forwarded a copy of the report to the MHS, attention Dennis Gimmestad, with a letter dated April 23, JoAnn M. Kryal, Superintendent, US Department of the Interior, National Park Service (NPS), Mississippi National River and Recreation Area (MNRRA): Letter dated April 30, COMMENT 2a: Ms. Kryal indicated that the statement under question 14, sentence 6, was incorrect, and provided the correct language, as follows: The 1988 federally-designated Mississippi National River and Recreation Area (MNRRA), a unit of the National Park System, was designated a state Critical Area in RESPONSE: Comment noted. See Errata. The history of Critical Area designation is rather complex. The Critical Areas Act was passed by the Minnesota Legislature in The Mississippi River Corridor was first designated a Critical Area by executive order in 1976, then redesignated by executive order in Also in 1979, the area was permanently designated a Critical Area by action of the Regional Development Commission (The Metropolitan Council) under the provisions of the Critical Areas Act. In 1991, the Minnesota Legislature designated the federal MNRRA as a Critical Area by the enactment of Minn. Stat. 116G.15. The Mississippi River Critical Area Corridor and MNRRA are geographically identical. COMMENT 2b: The NPS indicated that wastewater treatment is not specifically recognized as a compatible river use in the MNRRA Comprehensive Management Plan (CMP), but went on to say that the CMP does recognize the role of appropriate river-related industry. The NPS requested that language in the EAW be corrected accordingly. RESPONSE: Comment noted, see errata. COMMENT 2c: The NPS has no regulatory authority over local land use, but incorporates requirements of the Minnesota Critical Areas Act by reference into the MNRRA CMP. NPS urges the Minnesota Pollution Control Agency (MPCA) to incorporate comments received from the Minnesota Department of Natural Resources (DNR). RESPONSE: The City of Cottage Grove will require a Conditional Use Permit (CUP), as well as a variance from bluff line and property line setbacks which should address, at least in part, the Critical Area standards and guidelines. It will not be possible to satisfy all of these standards and guidelines to the letter, since the available site is small, and setback requirements are already not being met. Specific details relating to removal of fill, grading, landscaping, drainage, erosion prevention, stabilization of eroded areas, retaining walls, tree removal and replacement, and general restoration of vegetation have not completely been developed at this time. The MCES/WWS has submitted a CUP application to the City, which will formally review, comment, and act on the application. The NPS, DNR, and Environmental Planning and Evaluation Department of the MCES (MCES/EPE) are expected to comment

12 on the CUP, which includes an executive summary of a Natural Resource Management Plan, but not the detailed site plans that would complete that Plan. It is expected that Cottage Grove will issue a CUP approving the basic concept of the project, and then require submittal, for approval, of the detailed site plan. The detailed site plan would also be reviewed by the NPS, DNR, and MCES/EPE. The Metropolitan Council, as a Regional Agency, is required by Executive Order to submit plans that comply with the designation order. MCES/WWS is required by law and has committed to comply with the Critical Area Standards and intends to maximize the extent of compliance with the MNRRA CMP (which is voluntary). The MCES/WWS has demonstrated a commitment to work with the NPS and the DNR. Ultimately, however, the precise nature of that compliance will be negotiated between the reviewing agencies and the MCES/WWS during the review and approval of the detailed site plan. In a recent telephone conversation with Rebecca Flood of the MCES/WWSD, she indicated that copies of the CUP application and the detailed site plan would be provided to the DNR, the NPS, and the MCES/EPE. The comments of the DNR, the NPS, and the MCES/EPE, are part of the MPCA s formal record of decision on this project. COMMENT 2d: Our greatest concerns with regard to the project have to do with the impacts to the bluff face, impact to the bluff impact area, and loss of vegetative cover. We hope that any remaining slope and erosion/sedimentation issues will be resolved with the DNR prior to the beginning of construction. RESPONSE: See response to comment 2c, above. Robert C. Vogel, City Historical Preservation Officer, Advisory Committee on Historic preservation, City of Cottage Grove: Letter dated May 3, COMMENT 3: Mr. Vogel noted the BRW, Inc. archaeological survey/assessment had not been available to him for review. He indicated that he needed to review a copy of the report. RESPONSE: Craig Christenson of the MCES/WWS hand delivered a copy of the document to the City of Cottage Grove on April 29, 1999, for their review. See also the response to the comment by Mr. Gimmestad of the MHS. Martina Johntz, Assistant Planner, Washington County: Letter dated May 4, COMMENT 4: Ms. Johntz indicated that Washington County had no comments on the South Washington County WWTP EAW, but did have an interest in seeing the South Washington County Interceptor Route utilized as a trail and integrated as part of the linear parks system. RESPONSE: A copy of Ms. Johntz letter has been provided to the MCES and this request will be addressed as part of the South Washington County Wastewater Interceptor EAW, to be prepared late in 1999 or early in Scott Peters, Senior Transportation Planner, Minnesota Department of Transportation (Mn/DOT): Letter dated May 4, COMMENT 5: Mr. Peters indicated that Mn/DOT found the EAW acceptable as presented RESPONSE: Comment noted, no response necessary. 2

13 David Wulff, Supervisor, Policy Planning, and Analysis Unit, Minnesota Department of Health, (MDH). Letter dated May 5, COMMENT 6a: Complete plans for the plumbing system must be approved by the MDH prior to any construction. RESPONSE: The plumbing system plan review/approval has been incorporated into the list of permits/approvals in the Findings of Fact. A copy of this letter has been forwarded to the MCES, who will be responsible for assuring that plumbing plan review is completed. This plan review will be accomplished at a later phase of design. COMMENT 6b: The Minnesota Plumbing Code (Mn R , subp. 2) requires that a buried sewer be located at least 10 feet from a buried water service line. RESPONSE: A copy of this letter has been forwarded to the MCES, who will be responsible for assuring that the facility is compliant with the Minnesota Plumbing Code. COMMENT 6c: This comment summarized various requirements pertaining to setbacks between water supply wells and wastewater treatment plants, components thereof, and sewage collector lines and sanitary sewers. RESPONSE: The facility is a wastewater treatment facility and it will require a potable water supply. The site is extremely constrained and compliance with some of the setback distances may not be possible. During the next phase of the design-build process, it will be necessary to resolve these types of issues and secure specific permits. The contractor hired by MCES will be responsible for obtaining such permits. The Minnesota Well Code requires that a potable water supply well be constructed by a licensed well driller. That driller will be responsible for constructing the well in a manner compliant with the Minnesota Well Code. If the driller cannot do so, he must apply to the MDH for a variance from the Code. Typically, the variance will include additional requirements to protect the well from potential pollution, such as increased well depth, more extensive grouting than normally required, air-testing of the sewer lines. The variance is an administrative decision made by MDH staff. COMMENT 6d: The isolation distance from a community water supply well is no less than 50 feet for all types of sewer lines. RESPONSE: There is no community water supply well within 50 feet of any part of the project. COMMENT 6e: Minnesota Rules Chapter 4725 specify a setback of 20 feet from any stormwater pipes 12 inches or more in diameter. RESPONSE: No such stormwater pipes are anticipated in the proposed construction. Site runoff will flow either to the treatment plant or a special treatment unit. In any case, a copy of this comment letter has been forwarded to the MCES. COMMENT 6f: Construction activities shall not bury any well. RESPONSE: The existing well will be abandoned in accordance with the Minnesota Well Code. No other wells are known to exist in the project area. COMMENT 6g: Location of sewer main stubs should be planned so as to maintain isolation distances from wells and water lines. RESPONSE: No sewer main stubs will be constructed as part of the project. 3

14 COMMENT 6h: The MDH recommends an inventory of wells in and near the project area. RESPONSE: MCES has indicated that a formal well inventory will not be undertaken. Based upon their knowledge of the site and its environs, including various surveys for archaeological resources and wildlife that would have noted the location of any abandoned or existing structures or wells, a full inventory is not warranted. COMMENT 6i: Once the existing well is properly abandoned, isolation distance requirements will not apply. RESPONSE: Comment noted. No response is necessary Thomas Balcom, Supervisor, Environmental Review and Assistance Unit, Minnesota Department of Natural Resources. Letter dated May 5, COMMENT 7a: The DNR recognizes that evaluation of a design/build project in an EAW format requires reliance upon assumptions that may or may not eventually unfold at the site. They further indicated that the DNR needed to go on record relative to some of the project uncertainties. They commented extensively to the effect that exact details about several aspects of the project would be required in order for several DNR approvals and permits to be issued. The various DNR approvals/permits include the Protected Waters Permit for the outfall line and outfall structure, a Shellfish Taking Permit (potentially) and DNR s participation in the Critical Areas review process. The DNR has specifically indicated that, although some of these details are not yet resolved, the DNR does not believe that this present lack of resolution means that an Environmental Impact Statement (EIS) should be prepared on the project. RESPONSE: The MPCA recognizes that implicit in the design/build concept is the extensive reliance of the Responsible Governmental Unit (RGU) upon the ability of the many public entities with permit/approval authority to resolve uncertainties about the nature of specific details of the project. Through these approvals and permits, mitigation will be required so that the project will not have the potential for significant environmental effects. COMMENT 7b: Item 6d states that a separate EAW will be prepared for the additional 5 million gallons per day capacity. Some of the potential structures for this future, second phase activity are already shown on Alternative Site Plans, Figures 7-9. Given the constraints of this site, it is unclear whether additional structures that are not depicted in the site plan can be placed without contradicting the requirements of the Critical Area. Although it is appropriate to separate out this aspect of the project from this EAW, DNR will be reviewing both short-term and long-term projects in terms of Critical Area compliance. RESPONSE: Comment noted. If such expansion is proposed, it will require preparation of an EAW as well as many of the permits and approvals that apply to the present proposal. COMMENT 7c: Item 11a [of the EAW] identifies that a ravine slope found at the site, adjacent to a moderate-quality bedrock bluff prairie, will be "restored" to pre-development conditions. DNR may support such an action if it occurs under consultation with the Soil and Water Conservation District (SWCD) and the DNR Area Hydrologist. However, we have many questions about the desired outcome, the need for altering the top of the slope that has been in place over 30 years, and what is meant by the term "predevelopment conditions." Depending upon how "predevelopment conditions" are 4

15 interpreted, it is conceivable that efforts to try and achieve the contours on the east back to the preexisting 750 or 755 could come forward; such an approach would likely eliminate present-day structures or the 40 ft. bluff line setback. As such, DNR will need to review any proposed restoration or alteration of the ravine slope. RESPONSE: Comment noted. MCES/WWS has recently submitted a CUP application to the city of Cottage Grove. Part of that application is the Executive Summary of the Natural Resources Restoration Plan, which contains a general description of the restoration in the ravine area. The Plan itself has not been completed, as MCES/WWS is awaiting comments that will be received during the CUP review period. Subsequent to the issuance of the CUP, the MCES/WWS will be required to submit detailed site plans describing the restoration project. The site plans will be subject to public review and comment. COMMENT 7d: The Erosion and Sedimentation discussion in Item 16 identifies that slope stabilization is proposed to deal with existing erosion problems and address potential safety concerns. DNR will need to review and approve any plans to alter slopes greater than 18%, as well as plans to permanently reconstruct or reduce what is termed as "historical fill," especially for the amount of area referenced in the Natural Resource Management Plan for the project. RESPONSE: DNR and other public entities will be afforded a continuing opportunity to review and approve any proposed slope alterations or historical fill reconstruction during review of the CUP application as well as the review of detailed site plan. See response to comment 7c. COMMENT 7e: Regarding the proposed capture and treatment of all runoff generated on the site, which is discussed in Item 17, we commend this decision because minimizing runoff, and improving water quality of runoff, is a key Critical Area requirement. RESPONSE: Comment noted. No response needed. COMMENT 7f: Item 18, Water Quality - Wastewaters, indicates that the facility will meet a 1 mg/l annual phosphorus limit, which is to be accomplished by application of Bio-P treatment technologies. We commend MCES for this aspect of the project because it will substantially reduce the potential phosphorus loading to the Mississippi River, which is best captured in the table provided in Item 18. Essentially, daily phosphorus loading decreases by approximately 6.0 kg/day from current levels while the amount of treated effluent discharged to the receiving water increases four-fold. Both MPCA and DNR have identified cumulative phosphorus loading to the Mississippi River system as an ongoing issue of concern. As such, we believe the phosphorus limit being applied is consistent with actions already taken by other point-source WWTP discharges in the contributing watershed, and we congratulate MCES for its continuing leadership in this area. RESPONSE: Comment noted. No response is necessary. COMMENT 7g: Item 23, Stationary Source Air Emissions, notes that "[t]he project proposers are also evaluating the feasibility of including low head hydropower generation using the plant effluents minimal fall height down to the river." As we noted in our opening comments, substantial consultation has occurred between MCES and DNR on this project. However, use of the site for low head hydropower generation has not been a topic of discussion with DNR prior to this reference in the EAW. DNR will want to review details of potential structures, alterations, and impacts as they may relate to the Corridor. At what point will this decision be offered? RESPONSE: Decisions relating to low head hydropower generation will be made during subsequent phases of design. As long as the final decision is within the scope of the EAW project description, renoticing of the EAW would not be required. The final decision regarding low-head hydropower must also be consistent with the project description submitted for other reviews, permits, or approvals, such as the Cottage Grove CUP and detailed site plan. 5

16 COMMENT 7h: Item 25d correctly notes that scenic views and vistas can be affected by this project. Critical Area designation requires that site plans shall include measures which address adverse environmental effects and specific conditions with regard to buffering, landscaping, and revegetation, as well as retention of existing vegetation. The intent here is to prevent and mitigate irreversible damage to this state, regional, and national resource. DNR continues to place emphasis on having the potential project-related loss of trees and wildlife habitat mitigated with replacement, with the first preference occurring on the site itself. If mitigation and replacement is not totally possible onsite, then the next preference is on adjacent lands that reconnect the lost greenways in the Corridor. The third preference is for the action to take place within the [Mississippi River] Corridor in Cottage Grove. Tree replacement to mitigate Corridor losses should not occur outside the Corridor. DNR is committed to working with MCES as the project moves into permitting. Issues related to Critical Area compliance that DNR considers open at this time include, but are not limited to: site plan approval standards from Executive Order 79-19, including minimization of all adverse environmental effects; tree replacement alternatives, on- and off-site but within Critical Area Corridor; tree removal, in terms of flexibility of retaining wall placement to retain additional trees; details of administration building and other structures, in terms of height above the retaining wall, building design, and structure placement onsite; any underground retaining walls, anchors, or excavation within 40 ft. of the bluff line setback; prevention of adverse effects to bluffs from retaining wall construction methods; screening of retaining walls; slope stability and any alterations to east ravine bluff, in terms of vegetative/nonstructural solutions vs. structural ones; topographic alterations (i.e., amount and location, vegetation removal, existing vs. predevelopment conditions or historic pushing of bluffs); restoration of eroded areas, which should occur under the guidance of the SWCD and the DNR Area Hydrologist; outfall pipe, in terms of construction method and location/placement in or on the bluff and riverbanks; related vegetative cutting, impacts, and protection of the bluffs; disposition and/or use of existing effluent pipe; improvement of stormwater runoff quality, and stormwater management; timing of finalization of details of above issues in relation to City's conditional use permit application and site plan approval procedures; the City has expressed desire that all Critical Area issues be worked out with DNR prior to the City's decision; potential low-head hydropower generation; details of structures, methods, impacts need to be provided and addressed; DNR comments relating to the Natural Resource Management Plan, dated November, 1998; and any proposed overlook or public access, in terms of structure, location, and impacts. In closing, we do not recommend preparation of an EIS for the project. This conclusion offered, substantial issues of natural resource import remain uncertain from DNR's perspective. We recommend that MPCA, in its capacity as the RGU, continue to track project implementation to ensure that the project's complete potential impact profile has been adequately reviewed. 6

17 RESPONSE: Comment noted. The MPCA Staff recognizes DNR s concerns over unresolved issues pertaining to activities in and impacts upon the Mississippi River Critical Area and MNRRA. Issues relating to the Critical Area and MNRRA are being addressed during ongoing discussions between the MCES/WWS, who is responsible for facility design, and the DNR, the NPS, the City of Cottage Grove, and the MCES/EPE, who must review it for consistency with their program requirements. The DNR has critical area review authority over the City of Cottage Grove s CUP. The MCES/EPE is cooperating with the NPS in implementing the requirements that apply to MNRRA. MCES/WWS is faced with the challenge of compliance with the requirements of the CUP, the detailed site plan, the City Tree Replacement Ordinance, the Critical Areas Program and the MNRRA CMP, while still building the new facility on a 10-acre site, and assuring slope stability. MCES/WWS is submitting a Natural Resources Restoration Plan (a copy of the finalized executive summary of which is included with the comment letters), which addresses slope stabilization, removal of fill, filling gully areas, tree removal and replacement and restoration of native vegetation, among other issues. The executive summary is a part of the CUP Application, which has been provided to the NPS, the DNR, and the MCES/EPE. The CUP application will be reviewed by these interested parties for more than 30 days prior to action by the city of Cottage Grove, and they are able to provide comments to the city council. Upon approval of the CUP and the MPCA s NPDES permit, the MCES/WWS will prepare and distribute a Request for Proposals (RFP) to the contracting community, the City, the DNR, the NPS, the MPCA, and MCES/EPE. That RFP will include the Critical Areas standards and guidelines, and can be amended by MCES/WWS up to ninety days from its issuance, if the interested agencies have remaining concerns. The Design Builder must also submit a detailed site plan for City approval. These detailed site plans will be provided by MCES/WWS 30 days prior to City Council action on the site plan. Kim Lindquist, AICP, Community Development Director, City of Cottage Grove. Letter dated May 5, COMMENT 8a: On page 7, question 8, the approval table should list site plan approval by the city of Cottage Grove. RESPONSE: See errata. COMMENT 8b: On page 11, question 11b, the City wants to assure that the installation of the outfall in the river does not disrupt threatened and endangered species. RESPONSE: The various permits required by the DNR, the US Fish and Wildlife Service, and the US Army Corps of Engineers will protect any federally or state-listed endangered or threatened species. COMMENT 8c: It is unclear at this time whether the proposed plan meets the regulations and intent of the MNRRA and the Critical Area ordinance. RESPONSE: The NPS, the DNR, and MCES/EPE are all involved in review of the proposed plan, and will be involved in review of the CUP application, RFP review and detailed site plan submitted to Cottage Grove. COMMENT 8d: The comments made in the EAW (question 21) relate only to traffic generated when the plant is fully operational, not when it will be constructed. The city was concerned about truck traffic on local streets. The city indicated it had not come to agreement with the MCES/WWS regarding necessary upgrades to the local roadway system. RESPONSE: While truck traffic will increase over the short term during construction, it seems doubtful that this increase will adversely impact the roadway system. Truck travel frequency will be limited to shipment of concrete and other construction supplies. The same roadway system is used to transport sludge in trucks that weigh 10 to 15 tons. The truck traffic issue is being resolved between the City and MCES by providing an enforcement mechanism to proactively enforce maximum speed limits and by 7