City of Park Rapids WELLHEAD PROTECTION PLAN

Transcription

1 City of Park Rapids WELLHEAD PROTECTION PLAN Image of contractor sealing City well s 1 and 2 October 11, 2016 January

2 TABLE OF CONTENTS Page Number I. PUBLIC WATER SUPPLY PROFILE 3 II. EXECUTIVE SUMMARY 4 III. CHAPTER 1 - Data Elements, Assessment 9 IV. CHAPTER 2 - Impact of Changes on Public Water Supply Well(s) 12 V. CHAPTER 3 - Issues, Problems and Opportunities 14 VI. CHAPTER 4 - Wellhead Protection Goals 17 VII. CHAPTER 5 - Objectives and Plans of Action 17 VIII. CHAPTER 6 - Evaluation Program 27 IX. CHAPTER 7 - Alternative Water Supply; Contingency Strategy 27 X. APPENDIX A - Referenced Data for Part Acronym List -Glossary of Terms -Exhibit 1: Political Boundaries & Land Survey Map -Exhibit 2: Land Cover Map -Exhibit 3: Inner Wellhead Management Zone (IWMZ) Reports -Exhibit 4: PCSI List and Map -Exhibit 5: Zoning & Comprehensive Land Use Map -Exhibit 6: Sanitary Sewer System Map -Exhibit 7: Parcel Boundary Map -Exhibit 8: WHP Plan Part 1 2

3 PUBLIC WATER SUPPLY PROFILE PUBLIC WATER SUPPLY NAME: City of Park Rapids ADDRESS: 1425 Fair Ave S., Park Rapids, Minnesota TELEPHONE NUMBER: WELLHEAD PROTECTION MANAGER NAME: Scott Burlingame ADDRESS: 1425 Fair Ave S., Park Rapids, Minnesota TELEPHONE NUMBER: TECHNICAL ASSISTANCE NAME: Mike Strodtman, MRWA ADDRESS: Minnesota Rural Water Association th Ave SE Elbow Lake, MN TELEPHONE NUMBER:

4 PART 2 EXECUTIVE SUMMARY This portion of the wellhead protection (WHP) plan for the City of Park Rapids includes: the results of the Potential Contaminant Source Inventory, the Wellhead Protection Management Strategies, the Emergency/Alternative Water Supply Contingency Plan, and the Wellhead Protection Program Evaluation Plan. Part 1 of the wellhead protection plan presented the 1) delineation of the wellhead protection area (WHPA) and the drinking water supply management area (DWSMA) and 2) the vulnerability assessments for the system s wells and the aquifer within the DWSMA. Part 1 of the WHP plan was developed by Leffett, Brashears & Graham, Inc. and approved by the Minnesota Department of Health (MDH). The boundaries of the WHPA and DWSMA are shown in Figure 1. The vulnerability assessment for the aquifer within the DWSMA was performed using available information and indicates that the aquifer used by the system is considered to be moderately vulnerable to contamination because there appears some likelihood that a small amount of recharge from the surface is occurring. Consequently, the principal potential sources of contamination to the aquifer are other wells that reach or penetrate it, shallow disposal-type wells and storage tanks. This information was presented to the WHP Team during the Second Scoping meeting held with the MDH when the necessary requirements for the content of Part 2 were outlined and discussed in detail. The information and data contained in Chapters 1-4 of this part of the WHP Plan support the approaches taken to address potential contamination sources that have been identified as potentially affecting the aquifer used by the public water supply. The reader is encouraged to concentrate attention on Chapters 1-4 in order to better understand why a particular management strategy is included in Chapter 5. In Chapter 1, the required data elements indicated by MDH in the Scoping 2 Decision Notice are addressed, as well as the assessment of data elements. Pertinent data elements include information about the geology, water quality, water quantity, land use, and the public utility services. The data elements and information supplied in Part 1 of the WHP Plan are based on the assessment that the aquifer providing drinking water for this system is moderately vulnerable to contamination from land uses, such as other wells that penetrate the same aquifer and land uses that either store liquids in tanks or dispose of liquids below the land surface. Chapter 2 addresses the possible impacts that changes in the physical environment, land use, and water resources have on the public water supply. Only small changes in land use are expected and likely will not have significant impacts on the aquifer. Neither surface water nor groundwater changes are expected to impact the aquifer. The City of Park Rapids has evaluated the support necessary to implement its wellhead protection plan. Limited resources do pose a challenge due to the size of the community and the city will focus efforts on building partnerships with local and state resource agencies to cooperate and collaborate on drinking water protection efforts. The problems and opportunities concerning land use issues relating to the aquifer, well water, and the DWSMA, and those issues identified at public meetings are addressed in Chapter 3. The moderately vulnerable status of the aquifer and the water currently produced by the system s wells leaves four major concerns to be addressed by this plan: 1) other wells located within the DWSMA that could 4

5 become pathways for contamination to enter the aquifer; 2) the pumping effects of high-capacity wells that may alter the boundaries of the delineated WHPA, reduce the hydraulic head in the aquifer, or cause the movement of contamination toward the public water supply wells; 3) underground or aboveground storage tanks that may release contaminants into groundwater and 4) shallow disposal-type wells. No shallow disposal wells were identified, although aboveground and underground petroleum storage tanks, leak sites, and wells were identified in the DWSMA. The city will proactively monitor the establishment of other high capacity wells. The drinking water protection goals that the city would like to achieve with this plan are listed in Chapter 4. In essence, the City would like to, Promote public health, economic development and community infrastructure by maintaining a potable public drinking water supply for the community. The objectives and action plans for managing potential sources of contamination are contained in Chapter 5. Actions aimed toward educating the general public about groundwater and drinking water protection issues, proper well management, and collecting data relevant to wellhead protection planning are the general focus. Chapter 6 contains a guide to evaluate the implementation of the identified management strategies of Chapter 5. The wellhead protection program implementation efforts for the City of Park Rapids will be evaluated by the city at a minimum of every 2 ½ years. Chapter 7 is the emergency/contingency plan. The city has an approved DNR Water Supply Plan to meet the requirement of the Rule. 5

6 Summary of Wellhead Protection Actions Wellhead Protection Action Item Descriptions Public Education and Outreach Provide residents with an article that explains the importance of WHP. Request a large map of the DWSMA from MDH and display at public works building for staff and the public to view. Continue to maintain the posted wellhead protection sign around the DWSMA. Potential Contaminant Source Management Provide property owners, who have a well in the DWMSA materials on proper management of the well. If the City is made aware of any unused wells in DWSMA and the landowner is willing, apply for a grant to pay the costs to seal them. The City will collaborate with the MDH Source Water Protection Unit in the identification of new high-capacity wells that are proposed for construction within the DWSMA or within one mile of the DWSMA. The WHP Manager will share the location of pending high capacity well with the MDH Hydrologist. Provide property owners who have above ground tanks (1,100 gallons or greater) with materials on best management of the tank. In addition, work with the property owner to see if it is presently being used. Provide the property owners who have underground tanks with materials on best management of the tank. In addition, work with the property owner to see if it is presently being used. If a tank is found and it s determined the tank is no longer being used or any corrective action is needed, apply for funding to perform any corrective actions, including but not limited to, having the tank properly removed. WHP Team and Manager will update the PCSI map and table. Provide the owner of the Class V injection well with education resources on management of it. Inform MDH if a new Class V well is identified within the DWSMA. Review the MPCA website to see if status of leak/spill sites has changed or other applicable information is available. Land Use Management Send Todd Township a map of the DWSMA and letter discussing the importance of WHP. Work closely with the city Planning and Zoning department to use the zoning ordinance and comprehensive land use plan to continue the protection of the city s source of drinking water. Apply for grant and if successful, work with a consultant when updating the comprehensive land use plan to strengthen the language regarding the protection of the city s source of drinking water. Data Collection Contact the MDH Hydro regarding the sampling of wells for vulnerability parameters determined by the MDH, provided MDH will cover the costs. Continue to use longer pumping durations at lower rates to reduce the stress on the upper aquifer to hopefully reduce leakage from the upper aquifer. Request MDH to develop a groundwater monitoring plan using sentinel wells for the collection of synoptic water levels and groundwater samples. As Needed As Occurs As Occurs If Opportunity Arises As Occurs On going If Opportunity Arises On going 6

7 Wellhead Protection Action Item Descriptions The DNR is working on the Straight River Groundwater Management Area (SRGWMA) Plan and it s proposed that management activities will result at the conclusion of plan development. If the opportunity arises and grant dollars are available, the city will work with the DNR and others to assist in implementing the Plan as it pertains to the city s DWSMA. Request DNR and/or other agencies, as part of the GWMA study further explore the extent of the confining layer near unique well Send a letter to MDH Well Management requesting the SRGWMA be in a special well construction area and require full length grouting of all future wells to protect the upper confined aquifer. Inner Wellhead Management Zone Implement measures that are specified in the IWMZ PCSI report. Monitor and maintain the 200 ft. radius around the wells to ensure that setback distances for new potential contamination sources are met. Request MRWA or MDH assistance to update the Inner Wellhead Management Zone Inventory for the public water supply wells. Reporting and Evaluation Prepare an evaluation of WHP plan implementation efforts every 2 ½ years. Summarize all WHP Plan implementation efforts in a report to MDH prior to the Scoping 1 meeting for the WHP Amendment. Contingency Strategy Update the DNR Water Supply Plan. If deemed necessary, drill additional wells or look for an alternate well field. Apply for grant funds to assist in paying for associated costs. It is always difficult to foresee or plan for the future. The City will use its planning and management capabilities within this plan to help respond to new/unknown source water protection issues that may impact the quality or quantity of its drinking water in the future. As Occurs As Occurs As Occurs 7

8 Figure 1 WHPA and DWSMA Map 8

9 CHAPTER ONE DATA ELEMENTS, ASSESSMENT ( ) REQUIRED DATA ELEMENTS Physical Environment Data Elements Precipitation This data element does not apply because there is not a direct hydraulic connection between the land surface and surface waters and the aquifer serving this water supply system. Geology This data element is required and is presented in detail in the first part of the WHP Plan and thus is only summarized here. The water supply for the city of Park Rapids is obtained from one primary well. The geologic conditions at the well includes a cover of clayrich geologic materials over the aquifer that may retard the vertical movement of contaminants, although it is somewhat leaky. Because of this limited geologic protection, water from the aquifer is relatively young based on tritium analysis. Additional information is included in Part 1 and included in this Plan as Exhibit 8. Soils This data element does not apply because there is not a direct hydraulic connection between the land surface and the aquifer serving this water supply system. Water Resources This data element, as defined by the state wellhead rule, does not apply because there is not a direct hydraulic connection between the land surface and the aquifer serving this water supply system. Land Use Data Elements Land Use These data elements include information about parcel boundaries, political boundaries, potential contaminant sources, land use maps and zoning maps. A map showing the political boundaries and land survey map is included as Figure 1. The city s zoning map is included as Exhibit 5 in the Appendix, and the city has a comprehensive land use map to include in this plan. The parcel boundaries map showing the parcels for the properties located within the DWSMA is included in Exhibit 7 and can also be found on the County website. Land use within the DWSMA is a mixture of commercial, residential and agriculture. A generalized land cover map and table was provided by MDH and included as Exhibit 2 in the Appendix. The Inner Wellhead Management Zone (IWMZ) is a fixed two-hundred foot radius around each City well. The public water supplier is responsible to manage all potential contaminant sources identified within that area. The IWMZ was inventoried for potential contaminant sources for this planning process and that information can be found in the Appendix as Exhibit 3. Management strategies for the IWMZ are included in Chapter 5. Due to the moderately vulnerable designation of the DWSMA determined during the Part 1 WHP planning process, an inventory of other wells, storage tanks, spill or LUST sites, shallow disposal wells, and other potential contaminant sources located within the DWSMA is required, as identified in the Scoping 2 Decision Notice. A listing of potential contaminants inventoried within the DWSMA and a map showing their locations are included in the Appendix as Exhibit 9

10 4. At this time there is one shallow disposal wells (Class V wells) identified in the DWMSA. This site was inventoried during the first WHP Plan and the city will continue to provide them information regarding Class V wells and encourage them to continue to work with the EPA and follow all regulations. Public Utility Services Records of well construction and maintenance is used to support the development of Chapter 7 of this plan, which details an emergency plan for this system. These records are kept by city staff at the public works building. Highway 34 and 71 are a major transportation routes located in the DWSMA. The WHP Team feels these two highways are a concern, although not a major threat to the city s source of drinking water for the following reasons. There is a fair amount of truck traffic on these roads, although the majority of traffic comes north on Highway 71 then travels east on Highway 34, which is outside of the DWSMA. Secondly, the majority of storm water from these Highways is brought east to the Fish Hook River which is outside of the DWSMA. The City regularly maintains its sanitary sewer and public water supply system. The City does not have maps of size to include in the plan of the sanitary sewer and public water supply system. Maps are available and can be viewed at the public works building. There are no gas or oil pipelines located within the DWSMA, nor are there any public drainage systems. As necessary, the city hires a licensed well driller to perform standard maintenance on the city wells. The city has copies of applicable documents at the public works building. Water Quantity Data Elements Surface Water Quantity This data element does not apply because there is not a direct hydraulic connection between surface waters and the aquifer serving this water supply system. Groundwater Quantity Groundwater levels are adequate for the amounts that the City of Park Rapids is permitted for under the groundwater appropriations program that is administered by the Minnesota Department of Natural Resources (DNR). There are two high-capacity wells used for irrigation within the DWSMA, although no well interference complaints with the city s wells have been documented, and no water use conflicts are known to exist. The city is unaware of an existing list of wells covered by state appropriation permits, including the amount of water appropriated, type of use and aquifer source. The city inventoried two irrigation wells that assumedly have appropriation permits since they are large irrigation wells, although the city doesn t have any additional information. Table B1 located in the Part 1 includes a number of high capacity wells that were assessed in the area and the average volume of water pumped. There are no state environmental bore holes known of in the DWMSA, therefore no other applicable information about those wells is applicable regarding this data element. At this time, there appears to be sufficient groundwater quantity, based upon the existing pumping capacity of well(s) completed in the aquifer used by the system. This data element applies as it relates to future groundwater uses that may influence the ability of the aquifer to yield water to the City. Increased water use may result in a reduction in aquifer yield or increase the likelihood that contaminants of human or natural origin may affect the quality of drinking water. 10

11 Water Quality Data Elements Surface Water Quality This data element does not apply because there is not a direct hydraulic connection between surface waters and the aquifer serving this water supply system. Groundwater Quality These data elements include information about the overall water quality of the aquifer the City of Park Rapids is using for City purposes as well as other groundwater quality information generated from groundwater contamination studies. The city doesn t have an existing summary of water quality data including bacteriological contamination indicators, nor inorganic chemicals, nor organic chemicals. Although, a general overview of water quality data can be found in the city s Consumer Confidence Report which is provided to residents yearly. It is important to note that these water quality results do pertain to the water after treatment. Other existing information consists of isotopic and chemical analyses and indicates that the aquifer used by the City may be recharged by surface water. As such, there is a moderate probability that current land use has a direct impact on the quality of drinking water. Tests conducted by MDH have revealed traces of tritium, indicating there is some component of young water recharging the aquifer used by the system. There are three known existing reports of LUST sites in the DWSMA. One site is located at a gas station, another at Richard Rutherford s residence/business and the third is at the Fair ground where the bus garage is located. All these sites were investigated and are now considered closed by the MPCA, although in their documentation it indicates groundwater contamination, soil contamination and other unknown statuses for the sites. The city will continue to monitor the MPCA website to see if any changes to these records may occur during the life of the Plan. The city doesn t have an existing site study and well water analysis of known groundwater contamination nor an existing property audit identifying contamination. The city doesn t know of any groundwater tracer studies and isn t aware of any list of water chemistry and isotopic data from wells, springs, or other groundwater sampling points. ASSESSMENT OF DATA ELEMENTS A. Use of the Wells The city currently uses Well 9 as the primary public water supply well. The city plans to keep this arrangement into the future. A number of other high capacity wells were identified during the Part 1 WHP planning process. Wellhead Protection Area Delineation Criteria See the Part 1 WHP Plan for documentation regarding how the delineation criteria were applied to determine the boundaries of the WHPA. The Part 1 WHP Plan is included as Exhibit 8 in the Appendix. 11

12 The Part I WHP Plan also discusses in detail an assessment of the data elements used for delineation purposes. The city s Part 1 WHP Plan consultant and the MDH Hydrologist propose several recommendations to improve the data set for future delineation efforts. These recommendations are included as management strategies in Chapter 5 of this plan. Quality and Quantity of Water Supplying the Public Water Supply Well Water quality monitoring of well #9 since the well was drilled in 2013 indicates an upward trend in tritium and chloride. The city will continue to work with MDH on sampling of the well for further characterization of the area s hydrology. At the present time it is expected that the aquifer will yield sufficient quantities of water for the City of Park Rapids over the life of this plan. The Land and Groundwater Uses in the DWSMA Proactive management of existing wells, unsealed or unused wells, shallow disposal wells, and storage tanks are of concern in the moderately vulnerable DWSMA. The management strategies selected and documented in Chapter 5 of this Plan will focus on activities that have the most potential to impact the aquifer this city is using for its drinking water supply. Table 1 - Potential Contamination Sources and Assigned Risk for the IWMZ Source Type Total Level of Risk Sewer Line 1 M Storm Sewer Pipe 1 L Backwash basin 1 L Wells 8 M Table 2 - Potential Contamination Sources and Assigned Risk for the Rest of the DWSMA Potential Source Type Total Number Number Within Emergency Response Area and Level of Risk Number Within Remainder of the DWSMA and Level of Risk City Wells 4 4 L 0 L Domestic Well 34 1 M 33 M Monitoring well 4 4 M 0 - Old muni well Underground Storage Tank 8 2 M 6 M Aboveground Storage Tank greater than 1,100 gallons Class 5 Well L LUST sites 3 1 M 2 L 12

13 CHAPTER TWO IMPACT OF CHANGES ON PUBLIC WATER SUPPLY WELL(S) ( ) I. CHANGES IDENTIFIED IN: A. Physical Environment -- Large-scale changes in the physical environment within the DWSMA are not anticipated during the 10-year period that the WHP Plan is in effect. B. Land Use -- Land uses that result in additional water wells in the DWSMA are possible, although additional wells would likely have little impact on the aquifer unless water demand is increased to the point that 1) additional loss in hydraulic head occurs within the aquifer used by the City, or 2) pumping changes the boundaries of the WHPA. Constructing additional wells into the aquifer may increase the points of entry, alter the WHPA, or draw naturally-occurring or human-caused contaminants towards the City well. It is presumed that the land that is presently being used for crop production will continue to be used as such. There are other parcels in the DWSMA that have the potential to be developed. Land use within the DWSMA is a mixture of undeveloped, agriculture, residential and commercial. The city doesn t see a lot of land use changes in the DWSMA because much of the growth is on the eastern side of town and the agricultural land has a lot of value for production purposes and not likely for development. If development is to occur in the DWSMA some of it will be easily serviced with city utilities, although some portions are not which would result in the property owner drilling their own well. Over all, it isn t believed major changes will occur nor have an impact to the source of drinking water. Land use inside the Inner Wellhead Management Zone: The land within the 200-foot radius consists of city-owned property and a small percentage owned by the school district. Large scale land use changes are not expected to occur during the next 10 years within the IWMZs. Changes in land uses will be closely monitored due to the susceptibility of the aquifer to contamination from some types of activities at the land surface. C. Surface Water -- This data element does not apply because there is not a direct hydraulic connection between surface waters and the aquifer serving this water supply system. D. Groundwater -- The City well has historically provided groundwater of acceptable quality and quantity. As of the date of Plan approval, the City does not anticipate a large increase in water use or is not aware of any such water use expansions in the DWSMA or immediately adjacent area. Changes in water chemistry have been noted, although it is felt it is too early to determine what long term changes there might be, if any. II. IMPACT OF CHANGES List, Describe and Assess Impacts on Aquifer From: A. Expected Changes Identified Above - The city does not anticipate any changes so significant impacts on the aquifer are not expected. Since the construction of well #9 the water test results have shown an increase in tritium, 13

14 although the city doesn t feel the quality of water will be in jeopardy during the life of the plan. The city will continue to work the MDH and collect water samples to monitor any trends. C. Influence of Existing Water and Land Government Programs & Regulation - A number of local and state programs exist that may provide assistance and benefits in managing potential contaminant sources identified in the DWSMA. Following is a brief description of the major programs that have drinking water protection interactions. The Minnesota Department of Health regulates well construction through the Minnesota well code. Code requirements include minimum isolation distances as well as construction criteria designed to protect the well and aquifer. The MDH has a Source Water Protection grant program to assist in covering costs associated with the protection of source water. The Minnesota Pollution Control Agency has a tank storage program and has developed Best Management Practices (BMPs) for tank owners to help ensure proper and safe tank operation and maintenance. In addition, the MPCA manages a petroleum remediation program that addresses leaking tanks. This program has direct interaction with MDH staff in determining potential impacts to drinking water sources. The Hubbard County Soil and Water Conservation District administers cost share dollars for well sealing. The Hubbard County Local Water Management Plan has identified the protection of groundwater-based drinking water sources as a priority. There may be existing land use ordinances by local governments that could be revised in the future to address new private wells and storage tanks within the DWSMA. However, there is no discussion or intention at this time of requiring additional regulation related to managing wells or storage tanks within the system s DWSMA. The City requires homes and businesses to be connected to sewer and water where it is provided. The City of Park Rapids and Todd Township enforce their zoning ordinances which provide oversight and control to make sure orderly growth occurs within the city and township. C. Administrative, Technical, and Financial Considerations - The City of Park Rapids assembled a Wellhead Protection Team early in the process of developing this Plan. Many of the activities during the planning process have been accomplished through the efforts of this group, with assistance from studies provided by other units of government. For the WHP Plan to be effective: 1. The City will need to raise public awareness of the issues affecting the quality or quantity of its drinking water supply through public educational programs. 2. Administrative duties will remain with the Wellhead Protection Manager who will report to the governing authority, coordinate implementation of the wellhead protection management action plan, and conduct regular meetings. 3. The City has limited funds available for new programs and the implementation of wellhead protection activities. The City plans to utilize other sources of funding or in-kind services to help achieve the goals set forth in this Plan s Chapter 4 and include 1) the Hubbard County Soil and Water Conservation District and their well sealing cost-share program; 2) the MDH grant program; and 3) the Minnesota Rural Water Association providing technical assistance during the wellhead protection implementation phase. 14

15 CHAPTER THREE ISSUES, PROBLEMS, AND OPPORTUNITIES ( ) I. LAND USE ISSUES, PROBLEMS, AND OPPORTUNITIES The WHP Team identified water use and land use issues, problems, and opportunities related to the: aquifer serving the public water supply well, well water, and drinking water supply management area. The issues, problems, and opportunities were identified by assessing: problems and opportunities discussed at public meetings; data elements described in Chapter One; and the status and adequacy of official controls, plans, and other local, state, and federal programs on water use and land use. At the beginning of the planning process other Local Units of Government (LUGs) were identified and informed that the system was beginning the wellhead protection planning process. Each unit of government was also sent a copy of the delineated WHPA and DWSMA and vulnerability assessment for the wells and DWSMA. To date, no comments from the LUGs have been received. The general public was also given opportunities to participate in the planning process and to comment at the Public Informational Meeting and Public Hearing. No concerns from the general public have been expressed at this time. A. The Aquifer The aquifer used by the city is considered to exhibit a moderate geologic sensitivity because the over-lying clay-rich sediments that protect the aquifer are prone to leakage. The moderately vulnerable portions of the DWSMA should be relatively unaffected by land use activities with the exception of other wells, storage tanks, shallow disposal wells, or other potential contaminants identified in the Scoping 2 Decision Notice Attachment. B. The Well Water -- The wellhead protection plan is primarily concerned with other water supply wells, storage tanks and shallow disposal wells located within the moderate portion of the DWSMA. The potential contaminant source inventory performed by the Wellhead Protection Team indicated the types of potential contaminants, as listed in Tables 1 and 2. The placement of additional high-capacity wells, increased pumping from existing wells, or significant changes in current groundwater appropriations within the DWSMA may have an impact on 1) groundwater availability to all users, 2) increased risk that contamination may enter the part of the aquifer used by the public water supply wells, or 3) change the delineated WHPA and the DWSMA boundaries. There are other high capacity wells in and around the DWSMA, although no major water use conflicts are occurring. The City of Park Rapids will work with the DNR and MDH if the city becomes aware of any other proposed high-capacity wells. D. Drinking Water Supply Management Area - The state s Wellhead Protection Rule requires that existing information be utilized in developing the initial WHP Plan. Much of the data collected and utilized to delineate the city s WHPA and DWSMA and to determine the vulnerability of the aquifer to possible contamination comes from small-scale or regional studies. There is a limited amount of subsurface information available to define local groundwater flow 15

16 conditions and the groundwater chemistry of the aquifer within the DWSMA. The direction of groundwater flow was evaluated to address concerns that the current amount of subsurface information does not permit an unquestioned determination of local groundwater flow conditions toward the system s water supply wells. As a result, delineation of the WHPA represents a composite of capture zones generated by varying aquifer properties, within limits determined by MDH. A concern expressed by the City is to ensure consistent and long-term management of water wells, and observation and monitoring wells within the DWSMA. The City has limited legal capabilities to regulate well construction and sealing in the DWSMA. Second, changes in land use that increase pumping of the aquifer used by the City well need to be assessed for its possible impacts on water availability and quality. Finally, the City has no regulatory authority over water appropriations and must rely on the State of Minnesota to address issues and concerns related to water appropriation. The City will coordinate efforts with the State of Minnesota regarding any additional appropriation within the DWSMA. The DWSMA lies within the city limits and Todd Township. Both the city and township have zoning ordinances and authority over land use within this area. The WHP Team assessed the current and future land use changes in the DWSMA and concluded little or benign land use changes are likely. The City plans to utilize public education opportunities, both existing and proposed, to address potential contamination of the aquifer by other wells, storage tanks, shallow disposal wells, and other contaminant sources. Additionally, the City will work in cooperation with the Hubbard County Soil & Water Conservation District to utilize the well sealing cost-share program currently available, and participate in the MDH grant program to seal any unused wells. In review of the old muni well report, it is believed that all old municipal wells have been sealed. Further, the City will work with MDH to 1) identify proposed wells that may present groundwater conflict concerns, 2) ensure these wells are properly constructed, and 3) determine whether an alternative aquifer could/should be used. The WHP Team identified eight underground storage tanks within the boundaries of the DWSMA that are currently being used. The City will work with the property owners to promote BMP s or to facilitate the removal of these tanks by offering to pay for the associated cost if awarded a grant and the costs are feasible. No aboveground tanks have been identified to date. The City will continue to work with MPCA, MDA and MDH to 1) track current and likely future locations of tanks, 2) promote best management practices for all tanks, and 3) provide educational material to tank owners/operators. Shallow disposal wells (also called Class V Injection Wells) are regulated by the U.S. EPA. One Class V Injection Well was identified during the potential contaminant source inventory. The WHP Team is aware of the potential drinking water protection issues connected with this type of disposal system and will continue to provide the property owner with best management education materials and encourage them to continue to work with EPA. If any other Class V Injection Wells are identified, the city will inform MDH of its suspected location. There are many tools available to the regulating agencies that may be used to achieve the wellhead protection planning goal identified by the WHP Team. State and local governmental units, such as MDH, Hubbard County, and the DNR, regulate: 16

17 Well construction MDH; Well sealing MDH; State groundwater appropriation permits DNR; Public water supply quality MDH; Setbacks for specific contaminant sources from a well MDH and local governments through conditional use permitting; Land use controls Local governments; Tank control program MPCA, MDA; Shallow disposal wells - U.S. EPA. The WHP Team recommends that no additional regulations be imposed at this time and are confident that local issues may be adequately addressed through existing processes. Processes include zoning and land use, public education, adoption of best management practices for different types of wells, tank maintenance, and communication with landowners in the DWSMA. One issue identified by the WHP Team concerned whether there are adequate resources to implement wellhead protection activities. The small size of the City and the limited availability of time for staff indicate that it will be a challenge to implement the WHP Plan. The WHP Team will focus its efforts on fostering partnerships to help achieve the wellhead protection goal. The MDH, DNR, Hubbard County and Minnesota Rural Water Association were identified as valuable partners. CHAPTER FOUR WELLHEAD PROTECTION GOALS ( ) Goals define the overall purpose for the WHP plan, as well as the end points for implementing objectives and their corresponding actions. The WHP team identified the following goal after considering the impacts that 1) changing land and water uses have presented to drinking water quality over time and 2) future changes that need to be addressed to protect the community s drinking water: Promote public health, economic development and community infrastructure by maintaining a potable public drinking water supply for the community. CHAPTER FIVE OBJECTIVES AND PLANS OF ACTION ( ) Objectives provide the focus for ensuring that the goals of the WHP plan are met and that priority is given to specific actions that support multiple outcomes of plan implementation. Both the objectives and the wellhead protection measures (actions) that support them are based on assessing 1) the data elements, 2) the potential contaminant source inventory, 3) the impacts that changes in land and water use present and 4) issues, problems, and opportunities referenced to administrative, financial, and technical considerations. 17

18 Objectives The following objectives have been identified to support the goal of the WHP plan for the City of Park Rapids: 1. Create awareness and general knowledge about the importance of WHP in the City of Park Rapids. 2. Properly inventory and manage potential contaminant sources to protect the drinking water supply for the City of Park Rapids. 3. Gather additional information within the DWSMA in order to better understand the extent and vulnerability of the DWSMA. 4. Effectively track and report the implementation efforts and wellhead protection plan progress to appropriate governing authorities. 5. Manage the Inner Wellhead Management Zone to prevent contamination of the aquifer near the public supply wells. 6. Effectively prepare the City of Park Rapids for disruptions to the water distribution system. WHP Measures and Action Plan The WHP team has identified WHP measures that will be implemented by the city over the 10-year period that its WHP plan is in effect. The objective that each measure supports is noted as well as 1) the lead party and any cooperators, 2) the anticipated cost for implementing the measure and 3) the year or years in which it will be implemented. The following categories are used to further clarify the focus that each WHP measure provides, in addition to helping organize the measures listed in the action plan: 1. Public Education and Outreach 2. Potential Contamination Source Management 3. Land Use Management 4. Data Collection 5. IWMZ Management 6. Reporting and Evaluation 7. Water Use and Contingency Strategy Establishing Priorities Not all of these measures can be implemented at the same time, so the WHP team assigned a priority to each. A number of factors must be considered when WHP action items are selected and prioritized (part , subpart 3): Contamination of the public water supply wells by substances that exceed federal drinking water standards. Quantifiable levels of contamination resulting from human activity. The location of potential contaminant sources relative to the wells. 18

19 The number of each potential contaminant source identified and the nature of the potential contaminant associated with each source. The capability of the geologic material to absorb a contaminant. The effectiveness of existing controls. The time needed to acquire cooperation from other agencies and cooperators. The resources needed, i.e., staff time, legal, financial, and technical resources. The City of Park Rapids defines a priority for implementing a WHP measure as an action that protects their drinking water supply from contamination from a potential contaminant source or any other possible threat to the quality or quantity of its drinking water supply. The following table lists each measure that will be implemented over the 10-year period that the city s WHP plan is in effect, including the priority assigned to each measure. 19

20 High Medium Priority Low Low High Priority PUBLIC EDUCATION AND OUTREACH: WHP Plan of Action Description Objective Responsible Party & Cooperators Cost Implementation Time Frame WHP Measure (#1): Provide residents with an article that explains the importance of WHP. 1 City, MRWA $175 X X WHP Measure (#2): Request a large map of the DWSMA from MDH and display at public works building for staff and the public to view. 1 City Staff time X WHP Measure (#3): Continue to maintain the posted wellhead protection signs around the DWSMA. 1 City $150 As Needed POTENTIAL CONTAMINATION SOURCE MANAGEMENT: Description Objective Responsible Party & Cooperators Cost Implementation Time Frame WHP Measure (#4): Provide property owners, who have a well in the DWMSA materials on proper management of the well. 2 City, MRWA $150 X X WHP Measure (#5): If the City is made aware of any unused wells in DWSMA and the landowner is willing, apply for a grant to pay the costs to seal them. 2 City, MDH, MRWA Based on bids received As Occurs 20

21 Medium Medium Medium Medium Medium Medium Priority Description Objective Responsible Party & Cooperators Cost Implementation Time Frame WHP Measure (#6): The City will collaborate with the MDH Source Water Protection Unit in the identification of new high-capacity wells that are proposed for construction within the DWSMA or within one mile of the DWSMA. The WHP Manager will share the location of pending high capacity well with the MDH Hydrologist. WHP Measure (#7): Provide property owners who have above ground tanks (1,100 gallons or greater) with materials on best management of the tank. In addition, work with the property owner to see if it is presently being used. WHP Measure (#8): Provide the property owners who have underground tanks with materials on best management of the tank. In addition, work with the property owner to see if it is presently being used. WHP Measure (#9): If a tank is found and it s determined the tank is no longer being used or any corrective action is needed, apply for funding to perform any corrective actions, including but not limited to, having the tank properly removed City, MDH, DNR Staff time City, MRWA $100 X City, MRWA, MDH City, MRWA, MDH $100 Based on bids received X As Occurs X If opportunity Arises WHP Measure (#10): WHP Team and Manager will update the PCSI map and table. 2 City, MRWA $1,000 X WHP Measure (#11): Provide the owner of the Class V injection well with education resources on management of it. 2 City, MDH $150 X 21

22 Low Low Low Priority Low Medium WHP Measure (#12): Inform MDH if a new Class V well is identified within the DWSMA. 2 City, MDH Staff time As Occurs WHP Measure (#13): Review the MPCA website to see if status of leak/spill sites has changed or other applicable information is available. 2 City, MDH $75 X LAND USE MANAGEMENT: Description Objective Responsible Party & Cooperators Cost Implementation Time Frame WHP Measure (#14): Send Todd Township a map of the DWSMA and letter discussing the importance of WHP. 1 City, MRWA $100 X X WHP Measure (#15): Work closely with the city Planning and Zoning department to use the zoning ordinance and comprehensive land use plan to continue the protection of the city s source of drinking water WHP Measure (#16): Apply for grant and if successful, work with a consultant when updating the comprehensive land use plan to strengthen the language regarding the protection of the city s source of drinking water. 1 1 City, MRWA Staff time On going City, MRWA $1,500 If Opportunity Arises 22

23 Medium Low Medium Low Medium Medium Priority DATA COLLECTION: Description Objective Responsible Party & Cooperators Cost Implementation Time Frame WHP Measure (#17): Contact the MDH Hydro regarding the sampling of wells for vulnerability parameters determined by the MDH, provided MDH will cover the costs. WHP Measure (#18): Continue to use longer pumping durations at lower rates to reduce the stress on the upper aquifer to hopefully reduce leakage from the upper aquifer. WHP Measure (#19): Request MDH to develop a groundwater monitoring plan using sentinel wells for the collection of synoptic water levels and groundwater samples. WHP Measure (#20): The DNR is working on the Straight River Groundwater Management Area (SRGWMA) Plan and it s proposed that management activities will result at the conclusion of plan development. If the opportunity arises and grant dollars are available, the city will work with the DNR and others to assist in implementing the Plan as it pertains to the city s DWSMA. WHP Measure (#21): Request DNR and/or other agencies, as part of the GWMA study further explore the extent of the confining layer near unique well WHP Measure (#22): Send a letter to MDH Well Management requesting the SRGWMA be in a special well construction area and require full length grouting of all future wells to protect the upper confined aquifer City, MDH Staff time City $100 On going City, MDH City, MDH, DNR, MRWA City, MDH, MRWA, DNR City, MDH, MRWA Based on bids received Based on bids received Staff time Staff time X X X X As Occurs X X 23

24 Low Low Priority Medium High High Priority Inner Wellhead Management Zone: Description Objective Responsible Party & Cooperators Cost Implementation Time Frame WHP Measure (#23): Implement measures that are specified in the IWMZ PCSI report. 5 City $400 X X X X X X X X X X WHP Measure (#24): Monitor the 200 ft. radius around the wells to ensure that setback distances for new potential contamination sources are met. 5 City Staff time X X X X X X X X X X WHP Measure (#25): Request MDH or MRWA assistance to update the Inner Wellhead Management Zone Inventory for the public water supply wells. 5 City, MDH, MRWA Staff time X X REPORTING AND EVALUATION: Description Objective Responsible Party & Cooperators Cost Implementation Time Frame WHP Measure (#26): Prepare an evaluation of WHP plan implementation efforts every 2 ½ years. 4 City, MRWA Staff time X X X WHP Measure (#27): Summarize all WHP Plan implementation efforts in a report to MDH prior to the Scoping 1 meeting for the WHP Amendment. 4 City, MDH, MRWA Staff time X 24

25 Low Medium Medium Priority WATER USE AND CONTINGENCY STRATEGY: Description Objective Responsible Party & Cooperators Cost Implementation Time Frame WHP Measure (#28): Update the DNR Water Supply Plan. 6 City, MRWA $900 X WHP Measure (#29): If deemed necessary, drill additional wells or look for an alternate well field. Apply for grant funds to assist in paying for associated costs. WHP Measure (#30): It is always difficult to foresee or plan for the future. The City will use its planning and management capabilities within this plan to help respond to new/unknown source water protection issues that may impact the quality or quantity of its drinking water in the future. 6 6 City, MDH City, MDH To be determined with bids Staff time with unknown associated project costs As Occurs As Occurs 25

26 CHAPTER SIX EVALUATION PROGRAM ( ) The success of the wellhead protection management program must be evaluated in order to determine whether the plan is actually accomplishing what the City of Park Rapids set out to do. The following activities will be implemented to: Track the implementation of the objectives identified in Chapter 5 of this Plan; Determine the effectiveness of specific management strategies regarding the protection of the public water supply; Identify possible changes to these strategies which may improve their effectiveness; and Determine the adequacy of financial resources and staff availability to carry out the management strategies planned for the coming year. 1) The City will continue to cooperate with MDH in the annual monitoring of the water supply to determine whether the management strategies are having a positive effect and to identify water quality problems that may arise, which must be addressed. 2) It is recommended that the WHP Team meets on an annual basis, although it will meet a minimum of once every 2 ½ years, to document and review each strategy implemented during the previous 2 1/2 years. 3) The city will prepare a written report that documents how it has assessed plan implementation and the action items that were carried out. The report will be presented to MDH at the first scoping meeting held with the city to begin amending the WHP plan. CHAPTER SEVEN The city has an approved Department of Natural Resources (DNR) Water Supply Plan to fulfill these requirements. The city will continue to update the Plan as required by DNR. A copy of the Water Supply Plan is available at the Public Works Building. 26

27 APPENDIX A REFERENCED DATA FOR PART 2 Acronym List Glossary of Terms Exhibit 1: Political Boundaries & Land Survey Map Exhibit 2: Land Cover Map Exhibit 3: Inner Wellhead Management Zone (IWMZ) Reports Exhibit 4: Potential Contaminant Source Inventory List and Map Exhibit 5: Zoning & Comprehensive Land Use Map Exhibit 6: Sanitary Sewer System Map Exhibit 7: Parcel Boundary Map Exhibit 8: WHP Plan Part 1

28 Acronym List BMPs Best Management Practices CCR Consumer Confidence Report DNR Department of Natural Resources DWSMA Drinking Water Supply Management Area ERA - Emergency Response Area IWMZ Inner Wellhead Management Zone LUGs Local Unit of Government MDA Minnesota Department of Agriculture MDH Minnesota Department of Health MPCA Minnesota Pollution Control Agency MRWA Minnesota Rural Water Association PCSI Potential Contaminant Source Inventory PWS Public Water Supply SWCD - Soil and Water Conservation District US EPA United States Environmental Protection Agency WHP - Wellhead Protection WHPA Wellhead Protection Area

29 Glossary of Terms Data Element. A specific type of information required by the Minnesota Department of Health to prepare a wellhead protection plan. Drinking Water Supply Management Area (DWSMA). The surface and subsurface areas surrounding a public water supply well, including the wellhead protection area, that must be managed by the entity identified in the wellhead protection plan. (Minnesota Rules, part , subpart 13). This area is delineated using identifiable landmarks that reflect the scientifically calculated wellhead protection area boundaries as closely as possible. Emergency Response Area (ERA). The part of the wellhead protection area that is defined by a oneyear time of travel within the aquifer that is used by the public water supply well (Minnesota Rules part , subpart 3). It is used to set priorities for managing potential contamination sources within the DWSMA. Emergency Standby Well. A well that is pumped by a public water supply system only during emergencies, such as when an adequate water supply cannot be achieved because one or more primary or seasonal water supply wells cannot be used. Inner Wellhead Management Zone (IWMZ). The land that is within 200 feet of a public water supply well (Minnesota Rules, part , subpart 19). The City must manage the IWMZ to help protect it from sources of pathogen or chemical contamination that may cause an acute health effect. Nonpoint Source Contamination. Refers to contamination of the drinking water aquifer that is caused by polluted runoff or pollution sources that cannot be attributed to a specifically defined origin, e.g., runoff from agricultural fields, feedlots, or urban areas. Point Source Contamination. Refers to contamination of the drinking water aquifer that is attributed to pollution arising from a specifically defined origin, such as discharge from a leaking fuel tank, a solid waste disposal site, or an improperly constructed or sealed well. Primary Water Supply Well. A well that is regularly pumped by a public water supply system to provide drinking water. Vulnerability. Refers to the likelihood that one or more contaminants of human origin may enter either 1) a water supply well that is used by the City or 2) an aquifer that is a source of public drinking water. WHP Area (WHPA). The surface and subsurface area surrounding a well or well field that supplies a public water system, through which contaminants are likely to move toward and reach the well or well field (Minnesota Statutes, part 103I.005, subdivision 24). WHP Plan Goal. An overall outcome of implementing the WHP plan, e.g., providing for a safe and adequate drinking water supply. WHP Measure. A method adopted and implemented by a City to prevent contamination of a public water supply, and approved by the Minnesota Department of Health under Minnesota Rules, parts to WHP Plan Objective. A capability needed to achieve one or more WHP goals, e.g., implementing WHP measures to address high priority potential contamination sources within 5 years.

30 Exhibit 1: Political Boundaries & Land Survey Map Applicable information is shown on Figure 1

31 Exhibit 2: Land Cover Map & Table

32 Land Cover Table

33 Exhibit 3: IWMZ Reports

34

35

36

37

38 Exhibit 4: Potential Contaminant Source Inventory List and Map

39

40

41 Exhibit 5: Zoning Map - A large map is available at city hall for review.

42

43 Comprehensive Land Use Map

44 Exhibit 6: Sanitary Sewer and Water Maps Sewer and water maps are too large to include in this plan, although are available at Public Works Building.

45 Exhibit 7: Parcel Boundary Map

46 Exhibit 8: WHP Plan Part 1 Amendment to the Wellhead Protection Plan Part 1 Delineation of Wellhead Protection Area, Drinking Water Supply Management Area, and Drinking Water Supply Management Area Vulnerability Assessment December, 2015 Prepared for City of Park Rapids, Minnesota by Leggette, Brashears & Graham, Inc.

47 Table of Contents Page Glossary of Terms... i Acronyms... ii 1. Introduction Assessment of the Data Elements General Descriptions Description of the Water Supply System Description of the Hydrogeologic Setting Delineation of the Wellhead Protection Area Delineation Criteria Method Used to Delineate the Wellhead Protection Area Porous Media Delineations Results of Model Calibration and Sensitivity Analysis Calibration Sensitivity Analysis Addressing Model Uncertainty Conjunctive Delineation Delineation of the Wellhead Protection and Drinking Water Supply Management Areas Vulnerability Assessments Assessment of City Well Vulnerability Assessment of Drinking Water Supply Management Area Sensitivity Assessment of the Drinking Water Supply Management Area Vulnerability Comparing Original Part 1 to Amended Part Recommendations References List of Tables Table 1: Water Supply Well Information... 1 Table 2: Assessment of Data Elements... 2 Table 3: Description of the Hydrogeologic Setting at Well No Table 4: Description of WHPA Delineation Criteria... 5 Table 5: Annual Volume of Water Discharged from Water Supply Wells... 6 Table 6: Values Used In the Uncertainty Analysis... 11

48 Table of Contents - Continued List of Figures Figure 1: Site Location, High Capacity Wells, and Local Model Boundary Figure 2: Simulated Equipotential Contours Quaternary Upper Confined Aquifer Figure 3: Model Calibration Figure 4: Model Boundary and Calibration Locations Figure 5: 1-, 5-, and 10-Year Flowpaths for Calibrated Model and 10-Year Uncertainty Zones Figure 6: Combined Wellhead Protection Area Boundary and Drinking Water Supply Management Area Figure 7: Drinking Water Supply Management Area Geologic Sensitivity Assessment Figure 8: Drinking Water Supply Management Area Vulnerability Assessment Figure 9: Original and Amended Wellhead Protection Areas Appendix A Geologic Cross Sections Appendix B Other High Capacity Wells Included In Model

49 i Glossary of Terms Data Element. A specific type of information required by the Minnesota Department of Health to prepare a Wellhead Protection Plan. Drinking Water Supply Management Area (DWSMA). The area delineated using identifiable land marks that reflects the scientifically calculated wellhead protection area boundaries as closely as possible (Minnesota Rules, part , subpart 13). Drinking Water Supply Management Area Vulnerability. An assessment of the likelihood that the aquifer within the DWSMA is subject to impact from land and water uses within the wellhead protection area. It is based upon criteria that are specified under Minnesota Rules, part , subpart 3. Emergency Response Area (ERA). The part of the wellhead protection area that is defined by a oneyear time of travel within the aquifer that is used by the public water supply well (Minnesota Rules, part , subpart 3). It is used to set priorities for managing potential contamination sources within the DWSMA. Inner Wellhead Management Zone (IWMZ). The land that is within 200 feet of a public water supply well (Minnesota Rules, part , subpart 19). The public water supplier must manage the IWMZ to help protect it from sources of pathogen or chemical contamination that may cause an acute health effect. Wellhead Protection (WHP). A method of preventing well contamination by effectively managing potential contamination sources in all or a portion of the well s recharge area. Wellhead Protection Area (WHPA). The surface and subsurface area surrounding a well or well field that supplies a public water system, through which contaminants are likely to move toward and reach the well or well field (Minnesota Statutes, part 103I.005, subdivision 24). Well Vulnerability. An assessment of the likelihood that a well is at risk to human-caused contamination, either due to its construction or indicated by criteria that are specified under Minnesota Rules, part , subpart 2.

50 ii Acronyms ATP - Aquifer Test Plan CFR - Calculated Fixed Radius CWI - County Well Index DNR - Minnesota Department of Natural Resources EPA - United States Environmental Protection Agency FSA - Farm Security Administration MDA - Minnesota Department of Agriculture MDH - Minnesota Department of Health MGS - Minnesota Geological Survey MnDOT - Minnesota Department of Transportation MnGEO - Minnesota Geospatial Information Office MPARS Minnesota DNR Permitting and Reporting System MPCA - Minnesota Pollution Control Agency NRCS - Natural Resource Conservation Service SWCD - Soil and Water Conservation District UGE - Upgradient Extensions UMN - University of Minnesota USDA - United States Department of Agriculture USGS - United States Geological Survey

51 1 1. Introduction Leggette, Brashears and Graham, Inc. (LBG) has developed an Amended Part 1 of the Wellhead Protection (WHP) Plan for the City of Park Rapids, Minnesota (City) (public water supply identification number ). The work was performed in accordance with the Minnesota Wellhead Protection Rule (MR), parts to The results of the development of this WHP Plan Amendment are presented in the text below, on Tables 1 through 6, and in Figures 1 through 9, which are listed in the Table of Contents. This report presents delineations of the wellhead protection area (WHPA) and drinking water supply management area (DWSMA), and the vulnerability assessment for the public water supply well and DWSMA. Figure 6 shows the boundaries of the WHPA and the DWSMA. These are based on a WHPA that is defined by a 10-year time of travel. Figure 6 also shows the emergency response area (ERA) for City Well No. 9, which is defined by a 1-year time of travel. This report also lists the technical information that was used to prepare this portion of the WHP Plan in accordance with the MR. Information pertaining to the Determination of Aquifer Properties - Aquifer Test Plan (DAP-ATP) and the well vulnerability sheets can be obtained from the (Minnesota Department of Health) MDH. The City Wells included in the WHP Plan are listed in Table 1. Only wells listed as primary are required to be included in the WHP Plan. Table 1 - Water Supply Well Information Local Well Name Unique Number Type Casing Diameter (inches) Casing Depth (feet) Well Depth (feet) Date Constructed/ Reconstructed Well Vulnerability Aquifer Well No Well No Well No Well No Emergency Backup Emergency Backup Emergency Backup Emergency Backup Vulnerable QWTA Vulnerable QWTA Vulnerable QWTA Nonvulnerable QBAA Well No Primary Vulnerable QBAA QWTA- Quaternary Water Table Aquifer QBAA- Quaternary Buried Artesian Aquifer 2. Assessment of the Data Elements Table 2 presents the assessment of the data elements as outlined in the MDH s scoping letter relative to the present and future implications of planning items that are specified in MR, part

52 Use of the Well (s) Delineation Criteria Quality and Quantity of Well Water Land and Groundwat er Use in DWSMA 2 Table 1 - Assessment of Data Elements Present and Future Implications Data Element Data Source Precipitation H H H H MN Climatology Office, USGS Geology Maps and geologic descriptions M H H H MGS, DNR, USGS Subsurface data M H H H MGS, MDH, MPCA, USGS Borehole geophysics M H H H None available Surface geophysics L L L L None available Maps and soil descriptions L H M L NRCS Eroding lands Water Resources Watershed units L H L L National Hydrography Dataset (USGS) DNR, National Hydrography Dataset List of public waters L H L L (USGS) Shoreland classifications Wetlands map L H L L USFWS Floodplain map Land Use Parcel boundaries map L H L L Becker and Hubbard County GIS Data Political boundaries map L H L L ESRI Data Public Land Survey map L H L L ESRI Data Land use map and inventory Comprehensive land use map Zoning map Public Utility Services Transportation routes and corridors L H L L ESRI Data Storm/sanitary sewers and PWS system map L M L L City, Hubbard County Oil and gas pipelines map Public drainage systems map or list L H L L City, Hubbard County, DNR Records of well construction, maintenance, and use H H H H City, CWI Surface Water Quantity Stream flow data L H H H DNR, USGS Ordinary high water mark data L H L L DNR Permitted withdrawals L M L L DNR Protected levels/flows L H L L DNR Water use conflicts L H L L DNR Groundwater Quantity Permitted withdrawals H H H H DNR Groundwater use conflicts H H H H DNR Water levels H H H H DNR, MPCA, MDH, City

53 Use of the Well (s) Delineation Criteria Quality and Quantity of Well Water Land and Groundwat er Use in DWSMA 3 Present and Future Implications Data Element Data Source Surface Water Quality Stream and lake water quality management classification Monitoring data summary L H L L MDH, USGS Groundwater Quality Monitoring data H H H H MPCA, MDH Isotopic data H H H H MDH Tracer studies H H H H None available Contamination site data M M M M MPCA, MDA Property audit data from contamination sites MPCA and MDA spills/release reports H H H H MPCA Definitions Used for Assessing Data Elements: High (H) The element has a direct impact. Moderate (M) The element has an indirect or marginal impact. Low (L) The element has little if any impact. Shaded The element was not required by MDH for preparing the WHP Part 1 Plan 3. General Descriptions 3.1 Description of the Water Supply System The City has traditionally obtained its drinking water supply from City Wells No. 5, 6, 7, and 8, however, the current plan is to use City Well No. 9 exclusively and use the remaining four wells for emergency backup purposes only. All of the wells are shown on Figure 1 and Table 1 summarizes information regarding them. 3.2 Description of the Hydrogeologic Setting The hydrologic setting for the Quaternary Buried Artesian Aquifer (referred to herein as the upper confined aquifer) used by the City is described in detail in Helgesen, 1977; Lindholm et al., 1972; Ruhl, 1995; Stark et al., 1994; and Walsh Cross sections of the geology for the area are in Appendix A. There are three glacial aquifers in the Park Rapids area. A shallow sand and gravel aquifer exists at the surface and is called the surficial unconfined aquifer. Below that is a till of varying thickness referred to herein as the upper confining unit. Below the upper confining unit is the aquifer that contains City Well No. 9, referred to herein as the upper confined aquifer. The upper confined aquifer overlies a second confining unit and a lower confined aquifer. The surficial aquifer is generally unconfined and even dry in certain locations. It is persistent at or near the surface throughout the model domain, though there are areas southwest of the City where the aquifer is absent and till is predominant from the surface down to the lower confined aquifer. The

54 aquifer generally consists of sand and gravel. The aquifer ranges from 0 to more than 80 feet (25 m) thick and has widely varying reported hydraulic conductivity. The average value used in the model in Stark et al, 1992, was 215 ft/d (65 m/d). The upper confining unit is estimated to have a conductivity of less than 1 foot per day (ft/day) (approx. 0.2 m/d) (Stark et al., 1994) with a vertical conductivity of approximately 0.06 ft/d (0.019 m/d) (Blum, 2015; Delin, 1986). The confining layer thickness ranges from approximately 10 to 150 feet (3 to 45 m) and does appear to be absent in the area around CWI Well No , approximately 2.5 miles west northwest of City Well No.9. The upper confined aquifer is a generally confined sand and gravel aquifer that is present over much of the area around the City. The aquifer materials and the general hydrogeologic setting at City Well No. 9 are described in Table 3. The conductivity of the upper confined aquifer, as determined by a 2014 pumping test (see Table 3) is approximately 380 ft/d (117 m/d), which correlates well with the calibrated value of approximately 300 ft/d (92 m/d) from Stark et al, The thickness of the aquifer ranges from approximately 10 to 80 ft (3 to 25 m) and is now the primary source of water for the City as well as many of the local irrigation wells, some of which are within the capture zone of City Well No.9. Table 3 - Description of the Hydrogeologic Setting at Well No. 9 Aquifer Attribute Descriptor Data Source 4 Quaternary Buried Artesian Aquifer (QBAA) Aquifer Material Sand and Gravel City Well Logs Primary Porosity 0.25 Aquifer Thickness Stratigraphic Top Elevation Stratigraphic Bottom Elevation Hydraulic Confinement Transmissivity (T) Hydraulic Conductivity (K) Groundwater Flow Field Approx. 50 ft Typical of aquifer material (Fetter, 1988) City Well Logs and other logs in CWI 1,342.5 feet AMSL City Well No. 9 Log 1,294.5 feet AMSL City Well No. 9 Log Confined Reference Value 19,200 ft2/day Reference Value 384 ft/day (117 m/day) Flow generally to the east southeast Hydraulic Gradient: City Well No. 9 Log The reference value for the transmissivity of the sand and gravel aquifer was determined from a pumping test at Park Rapids TW (792199) in 2014 as analyzed in Blum, See above. Measured from model results. Flow generally east southeast and toward Long Lake with flow locally directed toward the rivers. Annual precipitation for the area is approximately 26 inches per year (in/yr) (MN DNR, 2015). The estimates of recharge to the aquifer are generally between 5.1 in/yr (0.13 m/yr) (Helgeson, 1777) and 12 in/yr (0.3 m/yr) (Stark et al., 1994). The original Part 1 plan used both 4.5 and 12.5 in/yr in their uncertainty analysis (Walsh, 2002).

55 Groundwater flow in the Park Rapids area is generally to the east southeast with local flow directed toward the lakes and rivers. The lakes and rivers in the area, including Portage, Fishhook, Straight and Long Lakes and the Shell, Fishhook and Straight Rivers, are generally discharge locations for groundwater. 4. Delineation of the Wellhead Protection Area 4.1 Delineation Criteria The boundary of the WHPA for the City Well No. 9 is shown in Figure 6. Table 4 provides descriptions of how the delineation criteria that are specified under MR, part were included in the model. Table 4 - Description of WHPA Delineation Criteria Criterion Descriptor How the Criterion was Addressed Flow Boundary Flow Boundary Daily Volume of Water Pumped Straight, Shell and Fish Hook Rivers plus local Lakes and wetlands Other High-Capacity Wells (Appendix B) See Table 5 Groundwater Flow Field See Figure 2 These features are used to define the flow field. Surface water features are represented using the MODFLOW river package, with the exception of an unnamed, intermittent tributary to the Straight River that is represented with the drain package. The pumping amounts were determined based on the averaged pumped volumes. The pumping amounts of these high-capacity wells were included in the methods used for the delineation. Pumping information was obtained from the Minnesota Department of Natural Resources Appropriations Permits The annual pumped volumes were converted to a daily volume pumped by a well. The model calibration process addressed the relationship between the calculated versus observed groundwater flow field. 5 Aquifer Transmissivity 19,200 ft2/day The reference value for the transmissivity of the Quaternary Buried Artesian Aquifer was determined from a pumping test on the Park Rapids Test Well. Time of Travel 10 years The public water supplier selected a 10-year time of travel.

56 6 Information provided by the City and from the Minnesota Department of Natural Resources (DNR) MPARS database was used to identify the maximum volume of water pumped annually by each well over the previous five-year period. The volumes pumped from the wells over the previous five years are summarized in Table 5. The volume used in the model for City Well No. 9 is the total amount used in 2010 (the highest total over the past 5 years) plus an additional 5 percent. As the City does not expect any increase in consumption over the next 5 years, this should be considered a conservative delineation volume. The daily volume of discharge used as an input parameter in the model was calculated by dividing the annual withdrawal volume by 365 days. Table 5 - Annual Volume of Water Discharged from Water Supply Wells Well Name Unique Number Total Annual Withdrawal (million gallons/year[mgy]) Maximum Withdrawal (MGY) 5-Year Projected Value (MGY) Withdrawal used in Current WHP Plan (m3/d) Well No. 5 Well No. 6 Well No. 7 Well No. 8 Well No ,290.4 Totals * 5, Sources: MPARS Permit Number and City of Park Rapids. * Value is the maximum over the past 5 years plus 5 percent. 4.2 Method Used to Delineate the Wellhead Protection Area Figure 6 shows the WHPA delineated for City Well No. 9 using the result of the porous media modeling delineation. The WHPA is a composite of all the areas identified using methods described in this report that potentially contribute recharge to the aquifer used by the City s well within a 10-year time of travel Porous Media Delineations The porous media delineation of the WHPA for City Well No. 9 was completed by creating a finite difference flow model using MODFLOW. MODFLOW is a 3D, cell-centered, finite difference, saturated flow model developed by the USGS (Harbaugh, 2005). The model domain was divided into a three-dimensional, non-uniform grid. The model has 222 rows, 234 columns, and three layers. Finer grid spacing was applied in the model with telescopic mesh refinement used in the area of Well No. 9. This grid spacing (2 m in the area of Well No.9) provides better definition in the area of the flow field where simulating the influence of pumping from the wells is critical.

57 There are three layers in the model to represent the surficial unconfined aquifer, the upper confining unit and the upper confined aquifer. The top elevation of layer 1 was defined by USGS 10 meter digital elevation data. The bottom of each of the layers were defined by interpolation of layer bottom elevation from sets of well log data from throughout the model domain Boundary conditions within the model were created using the river package to represent the rivers and lakes. The bed conductance for the rivers and lakes was set to be equal to the vertical conductivity of the surficial unconfined aquifer as the sand is generally present at the surface and groundwater discharge to the lakes and rivers would likely prevent a low conductivity riverbed from forming. Constant head boundaries were added to represent the groundwater surface in wetland areas between the lakes and rivers on the western boundary of the model and to account for upgradient flow into the model area. Recharge of approximately 8.6 in/yr (0.22 m/yr) was applied to the majority of the model area. A lower amount was applied to a small area along the south model boundary where there is considerable surficial till. The size of the domain and the general flow-field characteristics of the model were based on the results of the USGS model from Stark et al., 1992; and the original Part 1 WHP Plan. In addition to the previously mentioned information, the following data were incorporated in the refined model: The pumping rate from Table 5 was assigned to the Well No. 9. 1) The pumping rates from Appendix B were assigned to high-capacity wells located within the local model boundary. A set of 125 particles was launched from the cell containing Well No. 9 for a ten year time-of-travel using MODPATH, a flowpath calculation program. A porosity of 25 percent was used for the aquifers (Freeze and Cherry, 1979). As part of the uncertainty analysis, further groundwater pathline analyses, each consisting of 330 pathlines for a 10-year time-of-travel, were performed to delineate the 1-, 5- and 10-year capture zones and ultimately the WHPA. The resulting WHPA boundary (Figure 6) is a composite of the 10-year capture zones calculated using this model for the base case parameters and the parameter values used in the uncertainty analysis that is discussed in the following section. The model input files are available upon request from the MDH. 7

58 8 4.3 Results of Model Calibration and Sensitivity Analysis The goal of numerical model calibration is to obtain a reasonable correlation between the simulated model results and observed field data. The calibration process is generally completed by running a series of steady-state simulations (simulations where the flow magnitude and direction are constant with time), comparing calculated heads to the measured heads at wells within the model domain while changing the model parameters until the best match between the two is achieved. After a model is reasonably calibrated, a sensitivity analysis is used to determine the impact that changes to an input parameter have on the output of the model. In areas where there is a great deal of uncertainty in the physical parameters, either as a consequence of lack of data or based on the uncertainty associated with the interpretation of available data (i.e. pumping test analyses), a number of models are generally run to observe the effect on the model results over the range of potential values for each of the significant parameters. While none of the individual capture zones delineated as part of this analysis should be considered the correct one, it is assumed that the actual capture zone is encompassed by the resulting concatenation of the zones created during the uncertainty analysis Calibration The calibration plot, showing measured versus simulated hydraulic head values, for the model is illustrated on Figure 3. The plot shows that the simulated values and measured head values generally compare quite favorably and have a normalized root mean squared (NRMS) error of approximately 7 percent for observation points in the upper confined aquifer only and 5 percent for points measured in both the upper confined and surficial aquifers. Much of the error is likely due to the fact that observed head levels were measured over many years during highly variable conditions. River flows in the calibrated model were compared to measured flows reported in (Stark, et. al.), which were collected during the summer of One section of the river indicated a flow increase of approximately 11 cubic feet per second (cfs). The calibrated model computes an increase of approximately 10.1 cfs over this same section. A second section of river measured a 5 cfs increase compared to a modeled 4.5 cfs increase. While a single measurement of flow in the river is not meant to be definitive with respect to calibration, the fact that the modeled flows are similar is a good indication of the model s fitness for use in this particular study. More extensive observation data collected within the same general time period, more accurate, sitespecific transmissivity values throughout the model domain, and a better understanding of the potential connections between the upper confined and surficial unconfined aquifers as well as better definition of the recharge rate would improve calibration and model confidence. The groundwater flow field and hydraulic heads in the area of the City for the calibrated model are shown on Figure 2. The 1-, 5-, and 10-year capture zones, predicted using the calibrated model, are shown on Figure 4. However, due to the amount of variability associated with the physical characteristics of the aquifer; an uncertainty analysis was completed as part of the modeling effort Sensitivity Analysis Sensitivity is the amount of change in model results caused by the variation of a particular input parameter. For example, changing the hydraulic conductivity of an area can change the calculated head values in and around the area of the modified model as compared to the heads in unmodified model. Because of the relative complexity of the area of interest in this model, the size and orientation of the modeled capture zone may be sensitive to any of the input parameters:

59 9 The pumping rate determines the volume of the aquifer that donates water to the well. Increasing the pumping rate will expand the capture zone, for a given thickness, and decreasing it will make the capture zone smaller. Results The pumping rate for City Well No. 9 was defined by Minnesota Rules and, therefore, is not a variable for consideration in this analysis. However, the pumping rate for the irrigation wells is defined in the calibrated model using the annual rate. These wells are often only used over a 5-month period. This higher use over a shorter time period may have an effect on the capture zone for City Well No. 9, therefore, the uncertainty analysis includes some models with the wells pumping at the annual rate divided over five months (see Table 6). While the effect of using either the annual average or the five month average is not precisely correct, the actual effect on the capture zone of City well No. 9 should be between these two endpoints and the range should be considered conservative. The direction of groundwater flow and gradient can often be variable and change significantly with changing conditions such as fluctuations in local surface water elevations or the pumping rates in local wells. Results The regional flow direction and gradient were determined through the modeling process and resemble the flow direction and gradient determined through mathematical analysis of the measured heads in the area. The model was calibrated to hydraulic heads, and the calibration mirrored regional head data. Based on the regional observation data, the characteristics of the flow field, and the use of the aquifers of interest, there is not likely to be a significant change to the flow field. The hydraulic conductivity influences the size and shape of the capture zone. Additionally, a concern in the Park Rapids area is the migration of lower quality water from the surficial unconfined aquifer through the upper confining layer into the upper confined aquifer. Results - As the surficial unconfined and upper confined aquifers are composed of varying amounts of sand, gravel, and other materials, it is likely that the aquifer will have widely differing conductivity at various locations within the aquifer. Similarly, the confining unit between the two aquifers is also likely to have varying vertical resistance to flow at different locations. Due to this heterogeneity, ranges of hydraulic conductivity for the individual aquifers and the confining layer, shown in Table 6, were used in the uncertainty analysis. The river bed conductance influences the size and shape of the capture zone. This value is virtually always determined through estimation and calibration as the conductance is extremely hard to measure and can be quite variable. Results - The bed conductance for the rivers and lakes was set to be equal to the vertical conductivity of the surficial unconfined aquifer as the sand is generally present at the surface and discharge to the lakes and rivers would likely prevent a low conductivity riverbed from forming. Changes to the bed conductance of greater than an order of magnitude produced very little effect on either the flow field or the capture zone of City Well No. 9; therefore, bed conductance is not a variable for consideration in this analysis.

60 The aquifer thickness and porosity influence the size and shape of the capture zone by limiting the water-bearing volume within a given area of aquifer. Decreasing or increasing either thickness or porosity forces a proportional decrease or increase in the areal extent of the capture zone. Results - The thicknesses of the aquifers and confining unit within the model vary widely, from less than 10 feet (3 m) to over 180 feet (55 m) thick. The delineation and thickness used in the model were based on interpolations from actual well data in the area. These data may be inaccurate, overly simplified, or too widely spaced to precisely define the actual aquifer conditions. While the thickness of the aquifers and aquitards are not exactly known, the information used should be considered reasonable and is therefore not used as a variable for this evaluation. The porosity is typical for the materials and also not considered a variable. The recharge influences the size and shape of the capture zone by providing a defined volume of water within a given area of aquifer. Decreasing or increasing this volume of water will decrease or increase in the areal extent of the capture zone. Results - Annual precipitation for the area is approximately 26 inches per year (in/yr) and the estimates of recharge to the aquifer are as low as 5.1 in/yr (0.13 m/yr) (Helgeson, 1977) and as high as 12 in/yr (0.3 m/yr) (Stark et al., 1994). The original Part 1 plan used both 4.5 and 12.5 in/yr (Walsh, 2002). The wide range of potential recharge values requires that it be included in the uncertainty analysis. To be conservative, the range of recharge used for the uncertainty analysis was chosen to be slightly lower than the previous study at 4.0 to 12.1 inches per year. The values used can be found in Table Addressing Model Uncertainty Using computer models to simulate groundwater flow always requires that simplifying assumptions be made. Local geology can be highly variable and information from well logs and pumping tests indicates that this is likely the case near the City. Unfortunately, existing information is not detailed enough to define this degree of variability and interpretation of log and test data is often inconsistent. For models of the scale used in this study, the information and computational ability does not exist to precisely delineate the WHPA. To account for this, a number of models are run to examine the various potential WHPAs for the well, given the range of the input data mentioned previously. MODFLOW models were used to delineate capture zones for the upper confined aquifer that supplies water to City Well No. 9. As described previously, the hydraulic conductivity, annual recharge, and pumping rate for the irrigation wells were the primary variables identified that would potentially cause the greatest change in the WHPA for City Well No. 9. Capture areas were delineated for the assessed range of conductivities, recharge and pumping rate for a time-of-travel period of 10 years and the resulting concatenated capture zone defines the WHPA, shown on Figure 6. A total of 16 model runs were required to include the various input parameters. The first run was simply the base case, calibrated model using the values reported previously in this report. The nine uncertainty runs that followed individually examined the high and low values for each of the ranges associated with the conductivity values, the recharge rates, and the increasing the pumping rates for irrigation wells such that the annual value was pumped over only 5 months, to match typical use of irrigation wells. The final six uncertainty models were used to examine the combined effects of high and low values (e.g. high horizontal conductivity values in Layers 1 and 3 with low vertical conductivity in Layer 2). These combinations provide a wide range of potential conditions that could be encountered in the various aquifers. 10

61 The WHPA for City Well No. 9 (Figure 6) consists of a composite of the 16 porous media aquifer delineations for the different input parameters used in the sensitivity analysis listed in Table 6. This provides a conservative approach to addressing model uncertainty and produces a WHPA that is protective of public health. Table 6 - Values Used in the Uncertainty Analysis 11 Model Run Layer 1 (Kh) Conductivity Layer 2 (Kv) Layer 3 (Kh) Recharge ft/d m/d ft/d m/d ft/d m/d in/yr m/d Pumping Rate Base Model Month Avg. Uncert Month Avg. Uncert Month Avg. Uncert Month Avg. Uncert Month Avg. Uncert Month Avg. Uncert Month Avg. Uncert Month Avg. Uncert Month Avg. Uncert Month Avg. Uncert Month Avg. Uncert Month Avg. Uncert Month Avg. Uncert Month Avg. Uncert Month Avg. Uncert Month Avg. 4.5 Conjunctive Delineation Available hydrogeologic data near the City Wells and within the DWSMA, and the original Part 1 Plan, were reviewed to determine the potential need for a conjunctive delineation. After reviewing the data and the original Plan, a conjunctive was not necessary because the WHPA did not overlap any surface water features. 5. Delineation of the Wellhead Protection and Drinking Water Supply Management Areas After the porous media flow and the uncertainty analyses were completed, the capture zones delineated for each of them were plotted together. The outline of this concatenation created the final composite WHPA capture zone, shown on Figure 6, for use in delineating the Drinking Water Supply Management Area (DWSMA).

62 12 The boundary of the DWSMA was defined by LBG, the public water supplier, and MDH using roads, Public Land Survey System coordinates, and parcels (Figure 6). 6. Vulnerability Assessments The Part 1 Wellhead Protection Plan includes the vulnerability assessments for the public water supply well and DWSMA. These vulnerability assessments are used to help define potential contamination sources within the DWSMA and to select appropriate measures for reducing the risk that they present to the public water supply. 6.1 Assessment of City Well Vulnerability The City Well vulnerability assessment was conducted in accordance with the MDH guidance document, Assessing Well Vulnerability for Wellhead Protection (MDH, 1997). Vulnerability assessment rating sheets and vulnerability scores for Well No. 9 was obtained from the MDH and reviewed by LBG. The vulnerability of a well is scored based on the following six categories: DNR geologic sensitivity rating, casing integrity, casing depth, pumping rate, isolation distance from contaminant sources, and chemical and isotopic information. Based on these categories City Wells No. 9 is considered Vulnerable as a result of Tritium above 1 Tritium Unit (T.U.). The presence of Tritium above 1 T.U. automatically triggers a vulnerable rating. 6.2 Assessment of Drinking Water Supply Management Area Sensitivity The assessment of geologic sensitivity is a useful metric when estimating the relative vertical downward travel time of contaminants from grade level to the water table or source aquifer. A Level-3 DNR geologic sensitivity assessment was used for the City Wells. The Level-3 DNR geologic sensitivity rating is an empirical value determined by dividing the cumulative thickness of low permeability units above the aquifer by 10 (DNR, 1991). The resulting score is termed the L-score. A higher L-score indicates more low-permeability material above the aquifer, and therefore a lower vulnerability. A low L-score represents higher vulnerability. For example, a rating of L-1 has a higher vulnerability than L-9, because there is less low-permeability material present above the aquifer. A Level-3 assessment was conducted since the upper confined aquifer is overlain by varying thicknesses of clay. A Level-3 assessment was also conducted for all CWI wells located in the vicinity of the DWSMA delineation. The geologic sensitivity L-scores were calculated by LBG using a MDH Geographic Information System tool that utilizes lithology information from the MN CWI. Figure 7 illustrates the geologic sensitivity for the DWSMA as determined by mapping L-scores from well logs for wells near the DWSMA. Review of site-specific data from the CWI and LBG s 2012 Phase 2 Hydrogeologic Study Aquifer Test Results report indicates that a layer of low permeability material overlies the upper confined aquifer across the DWSMA. Although this layer of material appears continuous across the DWSMA, based on geologic logs in the area, the sand and gravel content in the clay till is variable. As a result, the geologic sensitivity is moderate in the north and south areas of the DWSMA. 6.3 Assessment of the Drinking Water Supply Management Area Vulnerability Once the geologic sensitivity was determined for wells near the DWSMA and for the area within the DWSMA, the vulnerability ratings could be determined. Since tritium has been detected above 1

63 Tritium Unit (T.U), the vulnerability rating was increased one level in areas where the geologic sensitivity could not explain the presence of Tritium (Figure 8). Vulnerability throughout the DWSMA and near City Well No. 9 is considered moderate. This rating implies that the upper confining unit is leaky and that water can travel from the land surface to the upper confined aquifer over a time period of years to decades (Geologic Sensitivity Project Workgroup, 1991) Comparing Original Part 1 to Amended Part 1 The original Part 1 was completed using an analytic element model to represent the aquifer. The Amended Part 1 employs MODFLOW to represent the complex geology of the aquifer using a finite difference model and allows for variable thickness as well as more comprehensive view of the local hydrogeologic system. The original Part 1 was for City Wells No. 4, 5, 6, and 7, which are all completed in the surficial unconfined aquifer. The Amended Part 1 combines all of the pumping from those wells into City Well No. 9, which is completed in the upper confined aquifer. The WHPA determined using the MODFLOW model is shorter and wider than the WHPAs from the original Part 1 as the surficial unconfined aquifer has a higher conductivity and this elongation of the WHPAs was exaggerated by using an even higher conductivity in the uncertainty analysis. While not producing a capture zone as long as the original Part 1, this model should be considered conservative and protective of the City s source water as it is modeling a different aquifer, based on conservative pumping data, and includes a wide-ranging uncertainty analysis. 8. Recommendations Upon completion of this Amended Part 1 WHP Plan, the following recommendations are provided for the City to consider for better understanding of the hydrogeologic conditions of the source aquifer and refinement of future WHPA delineations. Collect samples of City Well water from the surficial unconfined aquifer, and from Well No. 9 and conduct analysis of chloride, bromide, nitrate, ammonia, and tritium on an occasional basis and at year 6 of plan implementation at a minimum. The sampling should be done in conjunction with MDH, as the agency can help guide collection effort and compete the analysis at no charge to the City. 2) Consider exploring the area near CWI Well No to determine if the confining layer is, in fact, absent at that location and how large the potential connection is between the two aquifers in that area. Although not grant eligible because it is outside of the DWSMA, the work could be completed under DNR s Straight River Groundwater Management Area (GWMA) goals. 3) Examine the well construction of irrigation and other wells within the WHPA of City Well No. 9 to determine if any provide a conduit for water in the surficial unconfined aquifer to migrate to the upper confined aquifer. This measure could help promote full-length grouting of irrigation wells constructed across the upper confining unit, and can be associated with the goals of the GWMA and discussions with the responsible regulatory agency.

64 14 4) Develop a groundwater monitoring plan using sentinel wells for collection of synoptic water levels and collection of groundwater samples. Wells should be strategically selected and in the DWSMA to better assess the current groundwater flow direction and water quality trends. Periodic sampling can indicate potential breakthrough of nitrate or other contaminants to the upper confined aquifer and projected concentrations in City Well No. 9. If wells are not available, and/or not located in the ideal locations then new monitoring wells could be installed. If in the DWSMA, this type of measure could be eligible for a source water protection grant (SWP) grant. Evaluate how City Well No. 9 is operated to reduce the potential stress on the upper confined aquifer. Higher pumping rates could possibly enhance leakage through the upper confining unit. Consider longer pumping durations at lower rates. Continuous monitoring of water levels Well No. 9 and select observation wells adjacent to this would provide data beneficial to this assessment.

65 15 9. References Aquaveo, 2014, Groundwater Modeling System (GMS, version 9.2) [Computer Software], Provo, UT, Aquaveo, LLC. Blum, J., 2015, Analysis of the Park Rapids TW (792199) Pumping Test, October 9-24, 2014, Confined Outwash Aquifer, Minnesota Department of Health Memorandum to Park Rapids WHP Project file. Fetter, C.W., 1994, Applied Hydrogeology, 3rd ed.: Macmillan College Publishing, Inc., New York, 616 p. Freeze, R.A., and Cherry, J.A., 1979, Groundwater: Englewood Cliffs, NJ, Prentice-Hall, 604 p Geologic Sensitivity Project Workgroup, 1991, Criteria and guidelines for assessing geologic sensitivity of ground water resources in Minnesota, Minnesota Department of Natural Resources, Division of Waters, St. Paul, Minn., 122 p. Harbaugh, A.W., 2005, MODFLOW-2005, the U.S. Geological Survey modular ground-water modelthe Ground-Water Flow Process: U.S. Geological Survey Techniques and Methods 6-A16. Helgesen, J.O., 1977, Ground-water appraisal of the Pineland Sands area, central Minnesota: U.S. Geological Survey Open-File Report , 49 p. Lindholm, G.F., Oakes, E.L., Erickson, D.W., and Helgesen, J.O., 1972, Water resources of the Crow Wing River watershed, central Minnesota: U.S. Geological Survey Hydrologic Investigations Atlas HA-380. Minnesota Department of Health, 1997, Assessing Well and Aquifer Vulnerability for Wellhead Protection. Draft document, February 1997, pp. 23. Minnesota Department of Health, 2010, Minnesota public land survey system quarter-quarter sections (derived from section corners), computer file, St. Paul, MN. Minnesota Department of Natural Resources, 1991, Criteria and Guidelines for Assessing Geologic Sensitivity of Ground Water Resources in Minnesota. Minnesota Department of Natural Resources. Minnesota Department of Natural Resources Appropriation Permit Program Website ( Niswonger, R.G., S. Panday, and M., Ibaraki, 2011, MODFLOW-NWT, A Newton formulation for MODFLOW-2005: U.S. Geological Survey Techniques and Methods 6-A37, 44 p. Pollock, D.W., User's Guide for MODPATH/MODPATH-PLOT, 1994, Version 3: A particle tracking post-processing package for MODFLOW, the U.S. Geological Survey finite-difference ground-water flow model: U.S. Geological Survey Open-File Report , 6 ch.

66 Ruhl, J.F., 1995, Presence, Distribution, and Potential Sources of Nitrate and Selected Pesticides in the Surficial Aquifer Along the Straight River in North-Central Minnesota, U.S. Geological Survey Water-Resources Investigations Report , 30 p. Stark, J.R., Armstrong, D.S., Zwilling, D.R., 1994, Stream-Aquifer Interactions in the Straight River Area, Becker and Hubbard Counties, Minnesota: U.S. Geological Survey Water-Resources Investigations Report , 83 p. Walsh, J.F., 2002, Wellhead Protection Plan for the City of Park Rapids Part I Delineation of the Wellhead Protection Areas (WHPAs), Drinking Water Supply Management Area (DWSMA) and Assessments of Well and DWSMA Vulnerability. Minnesota Department of Health. 16

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77 27 Appendix A Geologic Cross Sections 27

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