Sun Prairie Village County Source Water Delineation and Assessment

Sun Prairie Village County Water and Sewer District Public Water System

PWSID # MT0000521

SOURCE WATER DELINEATION AND ASSESSMENT REPORT

Date of Report: 06/03/2005

Contact Person:

Bobby Broadway Sun Prairie Village County Water and Sewer District Post Office Box 1127 Great Falls, MT 59403

Phone: (406) 965-3944

Table of Contents EXECUTIVE SUMMARY ...... 8 INTRODUCTION ...... 10 PURPOSE...... 10 LIMITATIONS ...... 10 BACKGROUND...... 11 THE COMMUNITY ...... 11 GEOGRAPHIC SETTING...... 11 GEOLOGY...... 12 THE PUBLIC WATER SUPPLY ...... 13 WATER QUALITY ...... 14 SUN PRAIRIE VILLAGE WATER QUALITY...... 14 DELINEATION...... 15 HYDROGEOLOGIC CONDITIONS ...... 15 AQUIFER GEOMETRY AND HYDRAULIC CHARACTERISTICS ...... 16 POTENTIOMETRIC SURFACE...... 17 CONCEPTUAL MODEL AND ASSUMPTIONS ...... 18 WELL INFORMATION ...... 18 METHODS AND CRITERIA...... 19 DELINEATION RESULTS ...... 19 LIMITING FACTORS ...... 19 INVENTORY...... 20 INVENTORY RESULTS/RECHARGE REGION ...... 22 INVENTORY UPDATE ...... 22 INVENTORY LIMITATIONS ...... 22 SUSCEPTIBILITY ASSESSMENT ...... 23 MANAGEMENT RECOMMENDATIONS...... 25 MONITORING WAIVERS...... 27 MONITORING WAIVER REQUIREMENTS...... 27 USE WAIVERS ...... 27 WAIVER RECOMMENDATION...... 27 REFERENCES ...... 28 GLOSSARY* ...... 30 APPENDICES...... 34 APPENDIX A: SITE LAYOUT...... 35 APPENDIX B: WELL LOGS ...... 37 APPENDIX C: WATER USE STATISTICS...... 43 APPENDIX D: CONCURRENCE LETTER...... 45

FIGURES FIGURE 1. SUN PRAIRIE VILLAGE COUNTY VICINITY MAP FIGURE 2. SUN PRAIRIE VILLAGE COUNTY PWS WELL LOCATIONS FIGURE 2A. AERIAL MAP OF THE SUN PRAIRIE VILLAGE PWS VICINITY

FIGURE 3. SUN PRAIRIE VILLAGE AREA GEOLOGY FIGURE 3A. SUN PRAIRIE VILLAGE GEOLOGY (CONTINUED) FIGURE 4. POTENTIOMETRIC SURFACE NEAR SUN PRAIRIE VILLAGE SUPPLY WELLS FIGURE 5. SUNPRAIRIE VILLAGE INVENTORY REGION FIGURE 6. SUN PRAIRIE VILLAGE RECHARGE REGION FIGURE 7. LAND COVER IN THE SUN PRAIRIE VILLAGE INVENTORY REGION FIGURE 8. SEPTIC DENSITY WITHIN THE SUN PRAIRIE VILLAGE INVENTORY REGION FIGURE 9. LAND COVER IN THE SUN PRAIRIE VILLAGE RECHARGE REGION FIGURE 10. SEPTIC DENSITY WITHIN THE SUN PRAIRIE VILLAGE RECHARGE REGION

Tables TABLE 1. CLIMATIC SUMMARY FOR GREAT FALLS, MONTANA (243749) ...... 12 TABLE 2. WELL CONSTRUCTION AND PUMPING RATES FOR SUN PRAIRIE VILLAGE SUPPLY WELLS...... 14 TABLE 3. SOURCE WATER SENSITIVITY CRITERIA...... 15 TABLE 4. POROSITY VALUES FOR VARIOUS GEOLOGIC MATERIALS (EPA 1993)...... 16 TABLE 5. SOURCE WELL INFORMATION FOR THE SUN PRAIRIE VILLAGE PWS ...... 18 TABLE 6. SIGNIFICANT POTENTIAL CONTAMINANT SOURCES IN THE SUN PRAIRIE VILLAGE PWS INVENTORY REGION...... 21 TABLE 7. DETERMINATION OF HAZARD OF POTENTIAL CONTAMINANT SOURCES FOR UNCONFINED WELLS...... 23 TABLE 8. RELATIVE SUSCEPTIBILITY TO SPECIFIC CONTAMINANT SOURCES AS DETERMINED BY HAZARD AND THE PRESENCE OF BARRIERS...... 24 TABLE 9. HAZARD OF SIGNIFICANT POTENTIAL CONTAMINANT SOURCES FOR THE SUN PRAIRIE VILLAGE PWS INVENTORY REGION AND RECHARGE REGION ...... 24 TABLE 10. SUSCEPTIBILITY ASSESSMENT FOR SIGNIFICANT POTENTIAL CONTAMINANT SOURCES IN THE SUN PRAIRIE VILLAGE INVENTORY REGION AND RECHARGE REGION...... 24

EXECUTIVE SUMMARY

Sun Prairie Village is located in north-central Montana about 10-miles west of the City of Great Falls, and about 1-mile north of the Sun River in Cascade County. Drinking water for the Sun Prairie Village County Water and Sewer District (Sun Prairie Village) Public Water System (PWS) is supplied by four wells located in Section 34, Township 21 North, Range 2 East. This Source Water Delineation and Assessment Report was prepared under the requirements and guidance of the Federal Safe Drinking Water Act and the US Environmental Protection Agency, as well as a detailed Source Water Assessment Plan developed by a statewide citizen’s advisory committee here in Montana. The Department of Environmental Quality (DEQ) is conducting these assessments for all public water systems in Montana. The purpose is to provide information so that the public water system staff/operator, consumers, and community citizens can ensure strategies are in place to protect the source of drinking water. The information that is provided includes the identification of the area most critical to maintaining safe drinking water, i.e., the Inventory Region, an inventory of potential sources of contamination within this area, and an assessment of the relative threat that these potential sources pose to the water system.

Based on the well logs it appears that the Sun Prairie Village PWS wells withdraw water from a thin gravel and sand unit below the glacial lake deposits. Because the gravel and sand unit is overlain by glacial lake clay, it is considered to be a confined aquifer. In accordance with the Montana Source Water Protection Program criteria (1999), groundwater within this type of aquifer is considered to have a low sensitivity to potential contaminant sources. Sensitivity is defined as the relative ease that contaminants can migrate to source water through the natural materials.

Three source water protection management regions were identified for the Sun Prairie Village PWS as part of this assessment. They are the control zone, inventory region, and the recharge region. Potential contaminant sources were identified, where present, within each of these three regions and the results are as follows:

• The goal of management in the control zone is to avoid introducing contaminants directly into the water supply's well or immediate surrounding areas. The control zone is delineated as a 100- foot radius around the wells and all sources of potential contaminants should be excluded in this region. No significant potential contaminant sources were identified within the control zones.

• The inventory region should be managed to prevent contaminants from reaching the well before natural processes reduce their concentrations. The inventory region includes the area of land overlying the gravel and sand aquifer that supplies drinking water to these wells. A modified 1000-foot fixed radius inventory region was delineated around the Sun Prairie Village PWS well field.

The most significant potential contaminant sources identified within the inventory region include: area septic systems and cultivated cropland.

• The goal of management in the recharge region is to maintain and improve water quality over long periods of time or increased usage. Hydrogeologic mapping was used to delineate the recharge region for the PWS wells. Recharge to the wells is most likely from infiltration of precipitation and snowmelt in areas at a considerable distance to the west of Sun Prairie Village

where the gravel and sand are exposed. Groundwater flow appears to be from the northwest to southeast. No additional potential contaminant sources were identified in the recharge region

Susceptibility is the potential for a public water supply to draw water contaminated by inventoried sources at concentrations that would pose concern. Susceptibility is determined by considering the hazard rating for each potential contaminant source and the existence of barriers that decrease the likelihood that contaminated water will flow to the public water supply well. The Sun Prairie Village PWS has a low susceptibility to both area septic systems and cultivated cropland. Low risk potential contaminant sources and potential sources located outside the Inventory Region, but within the Recharge Region may still pose a threat over time, but are not discussed in detail in this assessment. This provides a quick look at the existing potential sources of contamination that could, if improperly managed or released, impact the source water for the Sun Prairie Village PWS. The susceptibility analysis provides the Sun Prairie Village PWS operator and homeowners with information concerning where the greatest risk occurs and where to focus resources for protection of their valuable drinking water resource.

The costs associated with contaminated drinking water are high. Developing an approach to protect that resource will reduce the risks of a contamination event occurring. The local geology and well construction issues have been summarized in this report as they pertain to the quality of your drinking water source. The area that is believed to be most critical to preserving your water quality (the Inventory Region) has been identified and within that area the potential contaminant sources have also been identified. In addition, recommendations are provided, i.e., Best Management Practices (BMPs), regarding the proper use and practices associated with the potential contaminant source. The information provided in this report will help increase awareness about the relationship between land use activities and drinking water quality.

INTRODUCTION

Carolyn DeMartino, a Water Quality Specialist with the Montana DEQ and Aubrey Smartt, a Montana Department of Environmental Quality (DEQ) Intern, completed the Sun Prairie Village (PWSID# MT 0000521) Source Water Delineation and Assessment Report (SWDAR). There are several operators for Sun Prairie Village Public Water System (PWS) including Bobby Broadway, Ronald Levandowski, Ricardo Trujillo, and Jan Steir.

A large portion of this SWDAR was taken directly from the Delineation of the Zone of Contribution Around Sun Prairie Village Supply Wells report completed by the Montana Bureau of Mines and Geology.

Purpose

This report is intended to meet the technical requirements for the completion of the delineation and assessment report for Sun Prairie Village PWS as required by the Montana Source Water Protection Program (DEQ, 1999) and the federal Safe Drinking Water Act (SDWA) Amendments of 1996 (P.L. 104-182).

The Montana Source Water Protection Program is intended to be a practical and cost-effective approach to protect public drinking water supplies from contamination. A major component of the Montana Source Water Protection Program is “delineation and assessment”. Delineation is a process of mapping source water protection areas, which contribute water used for drinking. Assessment involves identifying locations or regions in source water protection areas where contaminants may be generated, stored, or transported, and then determining the relative potential for contamination of drinking water by these sources. The primary purpose of this source water delineation and assessment report is to provide information that helps Sun Prairie Village complete a source water protection plan to protect its drinking water source.

Limitations

This report was prepared to assess the susceptibility of the Sun Prairie Village PWS to potential contaminant sources, and is based on published information and information obtained from local residents familiar with the community. The terms “drinking water supply” or “drinking water source” refer specifically to the source of the Sun Prairie Village PWS and not any other public or private water supply. Also, not every potential or existing source of groundwater or surface water contamination in the area of the Sun Prairie Village Subdivision has been identified. Only potential sources of contamination in areas that contribute water to its drinking water source are considered.

The term “contaminant” is used in this report to refer to constituents for which maximum concentration levels (MCLs) have been specified under the national primary drinking water standards, and to certain constituents that do not have MCLs but are considered to be significant health threats.

CHAPTER 1 BACKGROUND The Community

Sun Prairie Village is located in north-central Montana about 10-miles west of the City of Great Falls, and about 1-mile north of the Sun River in Cascade County (Figure 1). According to the Census Bureau the population of Cascade County in 2000 was at 80,357 with the population of the Sun Prairie Village subdivision being at 1,500 individuals.

The local economy is based mainly on agriculture and services located in surrounding towns such as Vaughn and Great Falls. The major transportation routes in the Sun prairie Village area are U.S. Interstate 15, U.S. Highway 87, U.S. Highway 89, and Montana State Highway 200. The Burlington Northern Railroad provides daily railway service.

The Sun Prairie Village subdivision is served by a community sanitary sewer system. Other area rural residences utilize septic systems to treat and dispose of sanitary wastes.

Geographic Setting

The Sun Prairie Village PWS wells are located in Section 34, Township 21 North, Range 2 East (Figure 2). See Figure 2a for an aerial view of the Sun Prairie Village PWS well field. The climate in this area is considered to be semi-arid. Average annual precipitation and temperature is 14.97 inches and 45 degrees Fahrenheit, respectively, at the Great Falls Municipal Airport, which is located on the plateau between the Sun and Missouri Rivers (National Oceanic and Atmospheric Administration 1996). Precipitation in May and June accounts for about one-third of the annual precipitation. A summary of the available climatic data for the Great Falls area is presented in Table 1.

Table 1. Climatic Summary for Great Falls, Montana (243749) Period of Record Monthly Climate Summary Period of Record: 1/1/1893 to 12/31/1956 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual Average Max. 33.8 35.7 44.3 57.8 66.8 74.4 84.4 82.4 70.8 60.3 45.5 36.9 57.8 Temperature (F) Average Min. 13.7 14.5 22.0 33.2 41.4 48.8 54.5 52.2 43.4 36.1 25.7 18.8 33.7 Temperature (F) Average Total 0.60 0.58 0.93 1.07 2.31 3.10 1.47 1.15 1.36 0.81 0.66 0.62 14.67 Precipitation (in.) Average Total 7.7 6.8 8.6 3.4 0.8 0.0 0.0 0.0 0.9 2.0 6.2 7.1 43.6 Snow Fall (in.) Average Snow 2 3 1 0 0 0 0 0 0 0 1 2 1 Depth (in.) Percent of possible observations for period of record. Max. Temp.: 90.7% Min. Temp.: 90.4% Precipitation: 90.2% Snowfall: 89.4% Snow Depth: 26.2% Source: Western Regional Climate Center, [email protected]

Sun Prairie Village is situated in a transition zone between the rugged Rocky Mountains to the west and gently rolling hills of the plains to the east. The topography around Sun Prairie can be described as consisting of broad, gently sloping plateaus traversed by rivers and streams whose valleys are relatively wide. The difference in altitude between river and stream valley bottoms and plateau summits is typically 200 to 500 feet. The altitude of Sun Prairie Village is about 3,360 feet; the summit of the plateau located north of Sun Prairie Village attains an altitude of about 3,880 feet.

Geology

Within 5 miles of Sun Prairie Village, rock units that crop out include the Kootenai and Black Leaf Formations of Cretaceous age; lacustrine and terrace deposits of Pleistocene age; and alluvial deposits of Holocene age (Figure 3 and Figure 3a). The Kootenai Formation consists of 350 to 400 feet of nonmarine strata. The upper part of the formation is composed mostly of interbedded, red, purple, green, yellow, or gray mudstone and shale; siltstone and sandstone beds occur in lesser amounts. The lower part of the formation consists of fine-grained sandstone, shale, and siltstone (Lemke 1977). The base of the Kootenai is formed by a 25 to 45 feet thick sandstone unit (Wilke 1983).

The Blackleaf Formation consists of about 680 to 800 feet of ' marine and nonmarine strata, and is comprised by four members, in ascending order: Flood, Taft Hill, Vaughn, and Bootlegger members. Marine strata of the Flood Member consists of three distinct units: a lower unit of sandstone and siltstone, a middle unit of dark gray shale, and an upper unit of cliff-forming sandstone. Marine Strata of the Taft Hill Member is composed chiefly of bentonitic clayey to silty shale and glauconitic sandstone, but contains beds of sandstone, siltstone, bentonite and calcareous concretions (glauconite is a green mineral formed during lithification of unconsolidated sediments). Non-marine strata of the Vaughn Member consists mostly of bentonitic clay, siltstone, and sandstone. Marine strata of the Bootlegger Member consists chiefly of interbedded sandstones, siltstones, and shales; the member also contains several bentonite beds 1 to 10 feet thick.

The Pleistocene terrace deposits are on upland surfaces higher than the Sun River flood plain; a terrace north of Sun River is about 500 feet above the flood plain. At least four other terraces step downward to the Sun River flood plain. The Sun River terrace, south of Great Falls, is the lowest terrace, and is about 15 to 20 feet above the Sun River flood plain.

The terraces are underlain by 15 to 20 feet of moderately well sorted, poorly stratified gravel. The gravel consists of well-rounded pebbles and cobbles of Precambrian argillite and quartzite which reflect source areas to the west, in the head waters of the Sun River (Maughan 1961). Sand either as lenses or as matrix in the gravel is scarce. The terrace gravels were deposited on planed or strathed bedrock when the Sun River and other streams channels were at higher elevations; since that time, regional uplift and down cuttings by the major streams have left the terrace gravel in the uplands.

The lacustine deposits consists mostly of well-sorted and stratified clay, silt, and very fine sand. The sediments were deposited in Glacial Lake Great Falls, which formed in response to a glacier blocking the ancestral Missouri and Sun Rivers, flooding the low lying areas. The lacustrine deposits are thin near outcropping bedrock, but may thicken to as much as 300 feet in the preglacial channels of the Sun and Missouri rivers (Wilke 1983), with the lower 100 feet consisting of plastic clay and silt (Lemke 1977). The lacustrine deposits rest on fractured and weathered bedrock in most places, but locally rests on a thin gravel and sandy unit that overlies the bedrock. It is this thin gravel and sandy unit that forms the aquifer for many wells drilled along the Sun River Valley including the Sun Prairie Village supply wells. River and stream alluvium underlies the Sun River flood plane and other stream flood planes. Alluvium underlying the Sun River flood plane consists of silt and sand with minor clay and gravel; its thickness ranges from 10 to 40 feet. Other stream flood planes are underlain by 3 to 15 feet of silt and clay with minor sand and gravel. A precise thickness for these deposits is difficult to establish because the alluvium and glacial lake deposits are similar and difficult to distinguish in the well boring.

The Public Water Supply

The Sun Prairie Village Water and Sewer District PWS is classified as a community system under the Federal Safe Drinking Water Act, because the system regularly serves at least 25 year-round residents through at least 15 service connections. The Sun Prairie Village PWS serves 1500 residents through 473 active service connections.

Sun Prairie Village County Water and Sewer District obtains its water from four supply wells all located about 1 ½ miles southeast of the development. Well #1 is an 8-inch steel well (WL002) drilled in 1976 to a depth of 199 feet. Well #2 is an 8-inch steel well (WL003) drilled in 1975 to a depth of 192 feet. Well #4 is an 8-inch steel well (WL005) drilled in 1976 to a depth of 193 feet. The casings of these three wells were not perforated or screened; therefore all water entered these wells through the open-ended casings. Wells #1, #2, and #4 were rehabilitated in 1991. Each of the three wells were drilled to about 202 feet. Well #1 had a 6-inch diameter screen installed from 189 to 201 feet. Wells #2 and #4 had a 6- inch diameter steel casing installed inside the existing 8-inch diameter casing and were perforated from about 194 to 202.5 feet.

Well #8 (WL007) was drilled in 1997 to a depth of 204 feet. There is a 10-inch diameter steel casing with an 8-inch diameter inner casing. A 6-inch diameter screen was placed in the well at approximately

190 to 203 feet.

The potential pumping rates for the wells are: Well #1 at 46, 780 cubic feet per day (243 gallons per minute); Well #2 at 60,640 cubic feet per day (315 gallons per minute); Well #4 at 52,940 cubic feet per day (275 gallons per minute), and Well #8 at 49,478 cubic feet per day (257 gallons per minute). The wells are pumped on a rotating basis to meet the demand during low use periods (late night/early morning and winter). During high use, at least two of the wells or all of the wells are pumped at the same time to meet the demand. None of the wells are pumped continuously during a 24-hour period. Water use statistics are listed in Appendix C.

Table 2. Well construction and pumping rates for Sun Prairie Village supply wells Well # Total Depth Screen Interval Pumping Rate Feet below land surface cubic feet per day 1 202 189 to 201 46,780 2 202 194 to 202.5 60,640 4 202 194 to 202.5 52,940 8 204 190 to 203 49,478

Water that is not directly distributed is stored in either a 415,000-gallon concrete tank or an 85,000- gallon glass-lined steel tank. A diagram of the site layout is included in Appendix A. Copies of the well logs are located in Appendix B.

Water Quality

The Sun Prairie Village PWS is classified as a community water supply. Therefore, the system conducts routine monitoring of the drinking water for contaminants in accordance with the Federal Safe Drinking Water Act. Parameters such as coliform bacteria, lead, copper, nitrate, nitrite, volatile organic chemicals (VOCs) including hydrocarbons and chlorinated solvents, inorganic chemicals including metals, synthetic organic chemicals including pesticides, and radiological contaminants must be monitored in accordance with schedules specified in the Administrative Rules of Montana. All contaminant concentrations detected in the required samples must comply with numeric maximum contaminant levels (MCLs) specified in the Federal Safe Drinking Water Act.

Sun Prairie Village Water Quality

Sun Prairie Village water quality is routinely monitored for compliance with drinking water standards. Bacteriological monitoring is conducted monthly. Compliance with other drinking water standards is based on additional sampling on a variety of schedules. Within the past five years there have been no coliform bacteria or fecal coliform bacteria detections in the Sun Prairie Village PWS wells. Nitrate plus nitrite as nitrogen ranging from 0.005 milligrams per liter (mg/L) to 0.08 mg/L has been detected in Sun Prairie Village's water within the past five years but remains well below the maximum contaminant level of 10 mg/L (DEQ SDWIS database).

CHAPTER 2 DELINEATION

The source water protection area, the land area that contributes water to the Sun Prairie Village PWS wells, is identified in this chapter. The management areas identified within the source water protection area included the control zone, inventory region, and recharge region. The control zone is an area at least 100-foot radius around the well. The management goal of the control zone, also known as the exclusion zone, is to protect against the direct introduction of contaminants into the well or in the immediate area surrounding each well.

The inventory region represents the zone of contribution of the well, which approximates a 1000-foot radius. The management goal of the inventory region is to focus on pollution prevention activities at potential contaminant sources where it is likely that contaminated water would flow into the well within a relatively short time frame.

The recharge region represents the entire portion of the aquifer that contributes water to the Sun Prairie Village water system. Management in the recharge region should focus on maintaining and improving the quality of groundwater that could reach each well over longer timeframes or with increased water usage.

Hydrogeologic Conditions

Sun Prairie Village is situated in the Sun River Drainage. With its headwaters in the rugged and remote Bob Marshall Wilderness Area near the Continental Divide, the Sun River flows east and joins the Missouri River about 8 miles east of Sun Prairie near Great Falls. A dam on the Sun River forms the Gibson Reservoir. Water released from the reservoir is distributed to several smaller holding reservoirs for distribution to about 110,000 acres of land.

South of Sun Prairie Village, the USGS operates gage 06089000 on the Sun River. At this gage, the Sun River drains about 1,850 square miles; average discharge is 696 cubic feet per second (U.S. Geological Survey 1996).

Sun Prairie Village supply wells withdraw water from the thin gravel and sandy unit below the glacial lake deposits. Driller's logs of most other wells completed along the Sun River flood plane indicate that these wells also withdraw water from the gravel and sandy unit. Because the gravel and sand unit is overlain by glacial lake clay, it is best described as a confined aquifer. Based on the confined nature of the aquifer and the criteria listed in Table 3, groundwater supplying the Sun Prairie Village PWS wells would have low source water sensitivity to potential contaminant sources.

Table 3. Source Water Sensitivity Criteria

Source Water Sensitivity High Source Water Sensitivity Surface water and GWUDISW Unconsolidated Alluvium (unconfined) Fluvial-Glacial Gravel Terrace and Pediment Gravel Shallow Fractured or Carbonate Bedrock Moderate Source Water Sensitivity Semi-consolidated Valley Fill sediments Unconsolidated Alluvium (semi-confined) Low Source Water Sensitivity Consolidated Sandstone Bedrock Deep Fractured or Carbonate Bedrock Semi-consolidated Valley Fill Sediments (confined)

Aquifer Geometry and Hydraulic Characteristics

The lateral extent and thickness of the gravel and sandy aquifer is not well known. Based on bedrock outcrop, lateral extent of the modern flood plane, and driller's logs, the aquifer may be up to 1.3 miles wide near Sun Prairie Village, and may extend several miles upstream and downstream. However, it should be recognized that the gravel and sand unit may thin and pinch out over a short distance.

An aquifer test by Chamberlain (1983) for two wells near Vaughn that were completed in the gravel and sandy aquifer indicated a transmissivity of about 16,000 feet per day. The gravel and sandy unit here is about 14-feet thick. An aquifer test on the Sun Prairie Village supply wells indicated a transmissivity of about 15,000 feet2 per day (White 1976). At Sun Prairie Village, the gravel and sandy unit is about 10- feet thick. The hydraulic conductivity (transmissivity divided by aquifer thickness) for the gravel and sandy aquifer at Vaughn and Sun Prairie Village is 1,140 feet per day and 1,500 feet per day, respectively. The hydraulic conductivity values agree well with values expected for gravel (Freeze and Cherry 1979).

Porosity is the volume of void spaces in a rock or sediment divided by the total volume of the rock or sediment. Aquifer porosity is needed to calculate travel time or distance. Porosity of the gravel and sandy aquifer could not be determined using Chamberlain (1983) and White's (1976) aquifer tests data. Table 4 lists porosity values for various materials.

Table 4. Porosity values for various geologic materials (EPA 1993).

Material Porosity (%) Specific Yieldl (% by volume) Specific Retention2 (%)

Soil 55 40 15 Clay 50 2 48 Sand 25 22 3 Gravel 20 19 1 Limestone 20 18 2

Sandstone 11 6 5 semiconsolidated Granite 0.1 0.09 0.01 Basalt, young 11 8 3 lThe amount of water yielded under the influence of gravity 2The ratio of the amount of water rocks or soils will retain against the pull of gravity to the rock/soil volume Source: U.S. EPA, 1990a.

Potentiometric Surface

A potentiometric-surface map was constructed using water levels measured in private water wells in March 1996 (Figure 4). The sparse number of wells completed in the gravel and sandy aquifer near Sun Prairie Village combined with either absent or disinterested well owners resulted in relatively few opportunities to measure water levels. As a result, the potentiometric surface is depicted for less than a square mile of the aquifer. As the potentiometric surface indicates, ground water in the gravel and sand aquifer near the Sun Prairie supply wells flows approximately from northwest to southeast. Upgradient of the supply wells, the potentiometric surface is not depicted, therefore it is assumed that ground water flows from the northwest to southeast, roughly parallel to the Sun River valley. The hydraulic gradient ranges from about 0.002 feet/feet north of the supply wells to about 0.001 feet/feet near the supply wells.

Ground-Water Recharge and Discharge

The gravel and sandy aquifer is recharged by inflow from adjacent bedrock aquifers, and locally (near a pumping well), by leakage from overlying glacial lake deposits. The aquifer may be recharged by precipitation in locations where the gravel and sand are exposed at the surface which is probably a considerable distance to the west of Sun Prairie Village. Discharge is by pumpage from wells and by leakage to overlying glacial deposits.

Conceptual Model and Assumptions

Groundwater located in a thin gravel and sandy unit below the glacial lake deposits supplies water to the Sun Prairie Village PWS wells. Because the gravel and sandy unit is overlain by glacial lake clay, it is considered a confined aquifer. Groundwater recharge to the aquifer is most likely from inflow of water from adjacent bedrock aquifers, and locally (near a pumping well), by leakage from overlying glacial lake deposits.

Well Information

Well information for the Sun Prairie Village wells is presented in Table 5.

Table 5. Source well information for the Sun Prairie Village PWS

Information Well #1 Well #2 Well #4 Well #8 PWS Source Code WL002 WL003 WL005 WL007 Well Location T. 21 N., R. 2 E., Sec. T. 21 N., R. 2 E., T. 21 N., R. 2 E., Sec. T. 21 N., R. 2 E., Sec. (T, R, Sec) 34 CBD Sec. 34 CBD 34 CBD 34 CBA Latitude/ Longitude 47.5284 / 111.4702 47.5284 / 111.4702 47.5284 / 111.4702 47.5303/-111.4702

MBMG # 34534 34537 34539 167886

Water Right # N/A N/A N/A P006853-00 Well Completion 12/26/1975 03/17/1976 01/23/1976 Date Rehabilitated Rehabilitated January Rehabilitated January 11/8/1997 January 1991 1991 1991 Total Depth (feet) After rehab 201 After rehab 203 After rehab 202 204 Screened Interval 189 to 201 194 to 202.5 194 to 202.5 190 to 203 (feet) Static Water Level 2 2 0 9.50 (feet) Pumping Water 30 32 30 100 Level (feet)

Drawdown (feet) 28 30' 30 90.5 Test Pumping Rate 65 GPM 100 GPM 90 GPM 750 GPM (GPM)

Methods and Criteria

DEQ’s Source Water Protection Program specifies methods and criteria used to delineate subregions of the source water protection area for the Sun Prairie Village PWS Wells. Because Sun Prairie Village obtains its water from four wells completed in a confined aquifer, a control zone for each well, an inventory region, and a recharge region have been delineated for the wells.

Delineation Results

A 100-foot control zone has been delineated around each of the Sun Prairie Village County Water and Sewer District PWS wells. A1000-foot fixed radius inventory region was delineated around all four of the wells due to their close proximity to one another (Figure 5). The recharge region for the wells was delineated using hydrogeological mapping (Figure 6).

Limiting Factors

The EPA analytical method assumes that the aquifer is homogeneous, isotropic, and of infinite aerial extent. The major assumptions of such methods are that flow in the aquifer is along a uniform gradient and horizontal. In addition, withdrawal rates are assumed to be constant over time. Limitations to this delineation include the spatial variability in aquifer properties. Groundwater flow within an aquifer is generally not uniform or strictly two-dimensional. Therefore, the aquifer is not homogeneous or isotropic, and withdrawals may vary over time.

CHAPTER 3 INVENTORY

An inventory of potential contaminant sources was conducted to assess the susceptibility of the Sun Prairie Village PWS to contamination, and to identify priorities for source water protection planning. The inventory for the Sun Prairie Village PWS focuses on facilities in the inventory region that generate, use, store, transport, or dispose potential contaminants, and on certain land types on which potential contaminants are generated, used, stored, transported or disposed. Additionally, the inventory process identifies potential sources of all regulated primary drinking water contaminants and pathogens. Only those potential contaminant sources that pose the most significant threat to human health were selected for detailed inventory. The most significant potential contaminants in the Sun Prairie Village PWS Inventory Region include nitrate, pathogens, fuels, solvents, herbicides, pesticides, and metals. The inventory for the Sun Prairie Village PWS also focuses on all activities in the inventory region, as well as general land uses and large potential contaminant sources in the recharge region.

Inventory Method

Available databases were initially searched to identify businesses and land uses that are potential sources of regulated contaminants in the inventory region. The following steps were followed:

Step 1: Land cover is identified from the most recent version of the National Land Cover Dataset compiled by the U.S. Geological Survey and U.S. Environmental Protection Agency (1992). Land cover types in this dataset were mapped from satellite imagery at 30-meter resolution using a variety of supporting information. Current land cover may not be reflected by this dataset in some areas where major growth has occurred. For example, land cover designated in the past, as agricultural land may now be commercial or residential land.

Step 2: EPA’s Envirofacts System was queried to identify EPA regulated facilities. This system accesses the following databases: Resource Conservation and Recovery Information System (RCRIS), Biennial Reporting System (BRS), Toxic Release Inventory (TRI), Permit Compliance System (PCS), and Comprehensive Environmental Response Compensation and Liability Information System (CERCLIS). The available reports were browsed for facility information including the Handler/Facility Classification to be used in assessing whether a facility is a significant potential contaminant source.

Step 3: DEQ databases were queried to identify Underground Storage Tanks (UST), hazardous waste contaminated sites, landfills, and abandoned mines.

Step 4: A business phone directory was consulted to identify businesses that generate, use, or store chemicals in the inventory region. Equipment manufacturing and/or repair facilities, printing or photographic shops, dry cleaners, farm chemical suppliers, and wholesale fuel suppliers were targeted by SIC code.

Step 5: Major road and rail transportation routes were identified.

Step 6. All significant potential contaminant sources were identified in the spill response region, and land uses and facilities that generate, store, or use large quantities of hazardous materials were identified within the watershed region.

Potential contaminant sources are designated as significant if they fall into one of the following categories:

• Large quantity hazardous waste generators • Landfills • Hazardous waste contaminated sites • Underground storage tanks • Major roads or rail transportation route • Cultivated cropland • Animal feeding operations • Wastewater lagoons or spray irrigation • Septic systems • Sewered residential areas • Storm sewer outflows • Floor drains, sumps, or dry wells • Abandoned or active mines

Inventory Results/Control Region

Land use in the 100-foot control zone of the wells consists of the pump house and the Sun River. There are no significant potential contaminant sources in the control zone.

Inventory Results/Inventory Region

Land cover within the Sun Prairie Village Inventory Region includes mainly pasture land, grassland, and cultivated cropland (Figure 7). Other types of land cover in the inventory region and their percentages are also identified on Figure 7. Septic density within the inventory region is composed of 54.5% moderate density and 45.5% low density immediately surrounding the well (Figure 8). The residences of Sun Prairie Village and the sewage holding pond are not located in the inventory region. Significant potential contaminant sources in the inventory region are listed in Table 6.

Table 6. Significant potential contaminant sources in the Sun Prairie Village PWS Inventory Region. Significant Potential Figure # Contaminants Hazard Contaminant Sources Effluent from improperly functioning septic systems Area Septic Systems Figure 9 Nitrates and pathogens discharging into area groundwater and impacting area groundwater SOCs, nitrates, Agricultural chemicals migrating into area Cultivated Cropland Figure 8 pathogens groundwater and impacting drinking water

Area Septic Systems – Moderate septic density occurs within the majority of the inventory region. Nitrates and pathogens could leach into area groundwater from septic tanks, associated piping, and the drain field if malfunctions occur.

Cultivated Cropland – Over application or improper handling of agricultural chemicals may impact area groundwater that is used for drinking water. Excessive irrigation may cause transport of contaminants or sediments to groundwater and surface water through runoff.

Inventory Results/Recharge Region

Land cover within the recharge region consists mainly of cultivated cropland and grassland (Figure 9). Other types of land cover in the recharge region and their percentages are also identified on Figure 9. Overall, septic density within the recharge region is low (Figure 10). No additional contaminant sources were identified in the recharge region.

Inventory Update

The certified operator of the Sun Prairie Village PWS should update the inventory every year. Changes in land uses or potential contaminant sources should be noted and additions made as needed. The complete inventory should be sent to DEQ every five years to ensure the source water delineation and assessment report remains current.

Inventory Limitations

The potential contaminant sources described in this section have been identified from readily available information. Consequently, unregulated activities or unreported contaminant releases may have been overlooked. In some cases, inadequate location information precluded the inclusion of potential contaminant sources in the inventory. The use of multiple sources of information, however, should ensure that the major threats to the source water for the Sun Prairie Village PWS have been identified.

CHAPTER 4 SUSCEPTIBILITY ASSESSMENT

Susceptibility is the potential for a public water supply to draw water contaminated by inventoried sources at concentrations that would pose concern. Susceptibility is assessed in order to prioritize potential pollutant sources for management actions by local entities, in this case Sun Prairie Village.

The goal of Source Water Management is to protect the source water by 1) controlling activities in the control zone, 2) managing significant potential contaminant sources in the Inventory Region, and 3) ensuring that land use activities in the recharge region pose minimal threat to the source water. Management priorities in the Inventory Region are determined by ranking the significant potential contaminant sources identified in the previous chapter according to susceptibility. Alternative management approaches that could be pursued by Sun Prairie Village to reduce susceptibility are recommended.

Susceptibility is determined by considering the hazard rating for each potential contaminant source. Hazard for confined wells is based on the criteria identified in Table 7.

Table 7. Determination of Hazard of Potential Contaminant Sources For Unconfined Wells Potential Contaminant High Hazard Rating Moderate Hazard Rating Low Hazard Rating Sources Well(s) in the inventory All wells in the inventory Point Sources of All PWS well is not sealed region other than the PWS region are sealed through the Contaminants through the confining layer well are not sealed through confining layer the confining layer

Septic Systems More than 50 – 300 Less than (density) 300 per sq. mi. per sq. mi. 50 per sq. mi.

Municipal Sanitary More than 50 percent of 20 to 50 percent Less than 20 percent of Sewer region of region region (percent land use)

Cropped More than 50 percent of 20 to 50 percent Less than 20 percent of Agricultural Land region of region region (percent land use)

The existence of barriers that decrease the likelihood that contaminated water will flow to the Sun Prairie Village wells also determines susceptibility (Table 8). Barriers to contamination can be anything that decreases the likelihood that contaminants will reach a spring or well. Barriers can be engineered structures, management actions, or natural conditions. Examples of engineered barriers are spill catchment structures for industrial facilities and leak detection for underground storage tanks. Emergency planning and best management practices are considered management barriers. Thick clay- rich soils, a deep water table or a thick saturated zone above the well intake can be natural barriers.

Table 8. Relative Susceptibility to Specific Contaminant Sources as Determined by Hazard and the Presence of Barriers Moderate Hazard High Hazard Rating Low Hazard Rating Rating Very High High Moderate No Barriers Susceptibility Susceptibility Susceptibility High Moderate Low One Barrier Susceptibility Susceptibility Susceptibility Moderate Low Very Low Multiple Barriers Susceptibility Susceptibility Susceptibility

Hazard ratings are presented individually for each significant potential contaminant source and each associated contaminant (Table 9).

Table 9. Hazard of significant potential contaminant sources for the Sun Prairie Village PWS Inventory Region and Recharge Region

Significant Potential Hazard Figure # Contaminants Hazard Contaminant Sources Rating

Area Septic Systems Figure 9 Nitrates and pathogens Leaching into groundwater Moderate

SOCs, nitrates, Contaminants leaching into Cultivated Cropland Figure 8 Moderate pathogens groundwater

Table 10 displays the susceptibility assessment results for the Sun Prairie Village PWS. The wells are susceptible to a number of different contaminants including nitrates, pathogens, agricultural chemicals, petroleum products, solvents, and total dissolved solids.

Table 10. Susceptibility assessment for significant potential contaminant sources in the Sun Prairie Village Inventory Region and Recharge Region.

Management Contaminant Hazard Susceptibilit Contaminant Hazard Barriers Recommendation Source Rating y s Area Septic Nitrates and Leaching into Moderate Overlying glacial clay, Low Monitor to insure Systems pathogens groundwater well intake depth proper maintenance Agricultural SOCs, nitrates, Enter river and Moderate Overlying glacial clay, Low Use Best land pathogens leach into the well intake depth Management groundwater Practices (BMPs)

The susceptibility results for each significant potential contaminant source and their associated contaminants are identified as follows:

Area Septic systems – Hazard is ranked moderate based upon septic system density. Overall, the susceptibility of the wells to contamination from septic systems is low as multiple barriers to contamination were identified

Agricultural land – Hazard is ranked moderate based on the cultivated cropland covers approximately 24% of the inventory region. The overall susceptibility is low as multiple barriers to contamination were identified.

Management Recommendations

The Sun Prairie Village PWS Source Water Delineation and Assessment Report was prepared to assist Sun Prairie Village to protect its source of drinking water. The report provides information concerning the wells that supply water to Sun Prairie Village, identifies the inventory region and the recharge region, and within each of these protection areas identifies the significant potential contaminants that may impact the source of water to Sun Prairie Village. Also provided in the table are recommendations regarding how the potential contaminant could be better managed to prevent impacts in the vicinity of the Sun Prairie Village wells. If these management recommendations are implemented, they may be considered additional barriers that will reduce the susceptibility of the Sun Prairie Village wells to specific sources and contaminants.

Management recommendations fall into the following categories:

Septic System maintenance. Encourage area property owners to implement proper operation and maintenance of their septic systems. This will also reduce the susceptibility of the Sun Prairie Village wells to contamination from this type of potential contaminant source.

Advanced Septic System Treatment. Installation of advanced septic treatment systems such as sand filters for future rural residences can limit contamination from septic systems.

Agricultural Best Management Practices. BMPs that address application and mixing of fertilizers and pesticides are a viable alternative to prohibition of their use. BMPs are voluntary but their implementation can be encouraged through education and technical assistance. BMPs may also be utilized to minimize surface runoff and soil erosion on cultivated fields

Stormwater Management. Stormwater planning should address source and drainage control. Source control can be accomplished through educational programs focusing on residential and commercial chemical use, disposal, and recycling. Drainage control and pollutant removal can be accomplished through the use of vegetated retention basins at outfall locations.

Education. Educational workshops provided to the general public by the county or state promote safe handling and proper storage, transport, use, and disposal of hazardous materials. Ongoing training provided to designated emergency personnel, such as the Sun Prairie Village PWS operators, would promote the efficiency and effectiveness of emergency responses to hazardous material spills. Educational workshops provided to rural homeowners will promote the proper operation and maintenance of residential septic systems. Educational materials covering these topics are available to the public and can be obtained from the US EPA and the State of Montana.

Emergency Response Plan. This is a management recommendation that Sun Prairie Village itself could develop and implement. Coordination with the City of Great Falls, Cascade County, and state emergency response personnel would greatly benefit the plan. The plan should identify the procedures the water operators and other emergency personnel should follow in the event that contaminants enter the groundwater and there is an imminent threat that the contaminated water would reach the PWS wells. The emergency response plan should be updated annually to reflect changes in emergency contacts, phone numbers, and resources available within the city and county to respond to an emergency situation, such as a hazardous material spill.

CHAPTER 5 Monitoring Waivers

Monitoring Waiver Requirements

The 1986 Amendments to the Safe Drinking Water Act require that community and non-community PWSs sample drinking water sources for the presence of volatile organic chemicals (VOCs) and synthetic organic chemicals (SOCs). The US EPA has authorized states to issue monitoring waivers for the organic chemicals to systems that have completed an approved waiver application and review process. All PWSs in the State of Montana are eligible for consideration of monitoring waivers for several organic chemicals. The chemicals diquat, endothall, glyphosate, dioxins, ethylene dibromide (EDB), dibromochloropropane (DBCP), and polychlorinated biphenyls are excluded from monitoring requirements by statewide waivers. Following is a description of a use waiver. Monitoring waiver recommendations for the Sun Prairie Village PWS follow these descriptions.

Use Waivers

A Use Waiver can be allowed if through a vulnerability assessment, it is determined that specific organic chemicals were not used, manufactured, or stored in the area of a water source (or source area). If certain organic chemicals have been used, or if the use is unknown, the system would be determined to be vulnerable to organic chemical contamination and ineligible for a Use Waiver for those particular contaminants.

Waiver Recommendation

Currently, Sun Prairie Village has a waiver for Phase II Inorganics and a monitoring waiver for asbestos that is in place from 2002 to 2010. Based on past monitoring results and the susceptibility assessment of the Sun Prairie Village PWS wells, the Sun Prairie Village PWS may be eligible for additional waivers. For further monitoring waiver consideration, the Sun Prairie Village PWS should submit a letter to DEQ requesting additional monitoring waivers. Additional information regarding chemical use on adjacent properties in the inventory region must accompany the waiver request letter.

REFERENCES

Broadway, B.B., 1996, Sun Prairie Village manager: written communication.

Camden, John. City-County Health Department. Sun Prairie Village Sanitary Survey. January 10, 2000.

Chamberlain, V. R., 1983, Geological Research and Engineering Co.: written communication to Vaughn Water Board.

Fisher, C.A., 1909, Geology and water resources of the Great Falls region, Montana: U.S. Geological Survey Water Supply Paper 221, 89 p.

Freeze, R.A., and Cherry, J.A., 1979, Groundwater: Prentice-Hall, Englewood Cliffs, NJ, 604p.

Lemke, R. W., 1977, Geologic map of the Great Falls quadrangle, Montana: U.S. Geological Survey GQ-1414, Scale 1:62,500.

Meek, J., 1996, Montana Department of Environmental Quality, Planning, Prevention, & Assistance Division, Pollution Bureau: written communication.

Maughan, E.K., 1961, Geologic map of the Vaughn quadrangle, Montana: U.S. Geological Survey GQ-135, Scale 1:62,500.

Montana Bureau of Mines and Geology, Groundwater Information Center.

Montana Department of Environmental Quality Public Water Supply Section Safe Drinking Water Information System (SDWIS).

Montana Department of Environmental Quality Underground Storage Tank Program web-site.

Montana Department of Environmental Quality “303(d) List, Montana List of Waterbodies In Need of Maximum Daily Load Development”, 1996.

Montana Department of Natural Resources and Conservation Water Rights Bureau.

National Oceanic and Atmospheric Administration, 1996, Local climatological data, annual summary with comparative data: Great Falls, 58 years of record.

Ross, Clyde P., Andrews, David A., and Witkind, Irving J., 1955, Geologic Map of Montana, Montana Bureau of Mines and Geology.

Solley, W .B., Pierce, R.R., and Perlman, H.A., 1993, Estimated Use of Water in the United States in 1990: U.S. Geological Survey Circular 1081 76 p.

Todd, D.K., 1959, Ground Water Hydrology: New York: John Wiley and Sons. 336 p.

U .S. Environmental Protection Agency, 1993, Wellhead Protection: A guide for small Communities. Office of Research and Development, Washington, DC.

U.S. Geological Survey, 1996, Water Resources Data for Montana, Water Year 1995.

United States Census Bureau, 2000

United States Environmental Protection Agency “Envirofacts Data Warehouse and Applications”.

United States Environmental Protection Agency “Know Your Watershed”.

United States Geological Survey. 1992. National Land Cover Dataset, Montana. 30 meter electronic digital landcover dataset interpreted from satellite imagery.

United States Geological Survey Selected Realtime Stream Flow Stations.

Western Regional Climate Center [email protected], Montana Climate Summaries. Sun Prairie Village, Montana. Recording station 243749, period of record 1/1/1893 to 12/31/1956.

White, S., 1976, Department of Natural Resources and Conservation, Water Rights Bureau: Hydrologic summary of application No. 6853-g41K.

Wilke, K. 1983. Appraisal of Water In Bedrock Aquifers, Northern Cascade County, Montana. U.S. Geological Survey Open File Report 82-1025.

GLOSSARY*

Acute Health Effect. A negative health effect in which symptoms develop rapidly.

Alkalinity. The capacity of water to neutralize acids.

Aquifer. A water-bearing layer of rock or sediment that will yield water in usable quantity to a well or spring.

Barrier. A physical feature or management plan that reduces the likelihood of contamination of a water source from a potential contaminant source

Best Management Practices (BMPs). Methods for various activities that have been determined to be the most effective, practical means of preventing or reducing non-point source pollution.

Biennial Reporting System (BRS). An EPA database that contains information on hazardous waste sites. The data can be accessed through the EPA Envirofacts website.

Chronic Health Effect. A negative health effect in which symptoms develop over an extended period of time.

Class V Injection Well. Any pit or conduit into the subsurface for disposal of waste waters. The receiving unit for an injection well typically represents the aquifer, or water-bearing interval.

Coliform Bacteria. A general type of bacteria found in the intestinal tracts of animals and humans, and also in soils, vegetation and water. Their presence in water is used as an indicator of pollution and possible contamination by pathogens.

Community. A town, neighborhood or area where people live and prosper.

Comprehensive Environmental Cleanup and Responsibility Act (CECRA). Passed in 1989 by the Montana State Legislature, CECRA provides the mechanism and responsibility to clean up hazardous waste sites in Montana.

Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). Enacted in 1980. CERCLA provides a Federal “Superfund” to clean up uncontrolled or abandoned hazardous-waste sites as well as accidents, spills, and other emergency releases of pollutants and contaminants into the environment. Through the Act, EPA was given power to seek out those parties responsible for any release and assure their cooperation in the cleanup.

Comprehensive Environmental Response, Compensation and Liability Information System (CERCLIS). A database that provides information about specific sites through the EPA Envirofacts website.

Confined Animal Feeding Operation (CAFO). Any agricultural operation that feeds animals within specific areas, not on rangeland. Certain CAFOs require permits for operation.

Confined Aquifer. A fully saturated aquifer overlain by a confining unit such as a clay layer. The static water level in a well in a confined aquifer is at an elevation that is equal to or higher than the base of the overlying confining unit.

Confining Unit. A geologic formation present above a confined aquifer that inhibits the flow of water and maintains the pressure of the ground water in the aquifer. The physical properties of a confining unit may range from a five-foot thick clay layer to shale that is hundreds of feet thick.

Delineation. The process of determining and mapping source water protection areas.

Glacial. Of or relating to the presence and activities of ice or glaciers. Also, pertaining to distinctive features and materials produced by or derived from glaciers.

Geographic Information Systems (GIS). A computerized database management and mapping system that allows for analysis and presentation of geographic data.

Hardness. Characteristic of water caused by presence of various calcium and magnesium salts. Hard water may interfere with some industrial processes and prevent soap from lathering.

Hazard. A relative measure of the potential of a contaminant from a facility or associated with a land use to reach the water source for a public water supply. The location, quantity and toxicity of significant potential contaminant sources determine hazard.

Hydraulic Conductivity. A constant number or coefficient of proportionality that describes the rate water can move through an aquifer material.

Hydrology. The study of water and how it flows in the ground and on the surface.

Hydrogeology. The study of geologic formations and how they effect ground water flow systems.

Inventory Region. A source water management area for ground water systems that encompasses the area expected to contribute water to a public water supply within a fixed distance or a specified three year ground water travel time.

Lacustrine. Pertaining to, produced by, or formed in a lake or lakes.

Leaking Underground Storage Tank (LUST). A release from a UST and/or associated piping into the subsurface.

Maximum Contaminant Level (MCL). Maximum concentration of a substance in water that is permitted to be delivered to the users of a public water supply. Set by EPA under authority of the Safe Drinking Water Act to establish concentrations of contaminants in drinking water that are protective of human health.

Montana Bureau of Mines and Geology – Ground Water Information Center (MBMG/GWIC). The database of information on all wells drilled in Montana, including stratigraphic data and well construction data, when available.

Montana Pollutant Discharge Elimination System (MPDES). A permitting system that utilizes a database to track entities that discharge wastewater of any type into waters of the State of Montana.

National Pollutant Discharge Elimination System (NPDES). A national permitting system that utilizes a database to track entities that discharge wastewater into waters of the United States.

Nitrate. An important plant nutrient and type of inorganic fertilizer that can be a potential contaminant in water at high concentrations. In water the major sources of nitrates are wastewater treatment effluent, septic tanks, feed lots and fertilizers.

Nonpoint-Source Pollution. Pollution sources that are diffuse and do not have a single point of origin or are not introduced into a receiving stream from a specific outlet. Examples of nonpoint- source pollution include agriculture, forestry, and runoff from city streets. Nonpoint sources of pollution, such as the use of herbicides, can concentrate low levels of these chemicals into surface and/or ground waters at increased levels that may exceed MCLs.

Pathogens. A microorganism typically found in the intestinal tracts of mammals, capable of producing disease.

Permit Compliance System (PCS). An EPA database that provides information on the status of required permits for specific activities for specific facilities. The data can be accessed through the EPA Envirofacts website.

Phase II (and IIb) Rules. EPA updated or created legal limits on 38 contaminants. The rules became effective July 30, 1992 and January 1, 1993. Some of these contaminants are frequently-applied agricultural chemicals such as nitrate and others are industrial solvents.

Phase V Rule. EPA set standards for 23 contaminants in addition to those addressed by the Phase II Rules. The Phase V Rule became effective January 17, 1994. Some of these contaminants include inorganic chemicals such as cyanide and other Phase V contaminants are pesticides that enter water supplies through run-off from fields where farmers have applied them or by leaching through the soil into ground water. Six are probable cancer-causing agents. Others can cause liver and kidney damage, or problems of the nervous system and brain.

Point Source. A stationary location or a fixed facility from which pollutants are discharged. This includes any single identifiable source of pollution, including but not limited to any pipe, ditch, channel, tunnel, conduit, well, discrete fracture, container, rolling stock (tanker truck), or vessel or other floating craft, from which pollutants are or may be discharged.

Pollutant. Generally, any substance introduced into the environment that adversely affects the usefulness of a resource (e.g. groundwater used for drinking water).

Public Water System (PWS). A system that provides water for human consumption through at least 15 service connections or regularly serves 25 individuals.

Pumping Water Level. Water level elevation in a well when the pump is operating.

Recharge Region. A source water management region that is generally the entire area that could contribute water to an aquifer used by a public water supply. Includes areas that could contribute water over long time periods or under different water usage patterns.

Resource Conservation and Recovery Act (RCRA). Enacted by Congress in 1976. RCRA's primary goals are to protect human health and the environment from the potential hazards of waste disposal, to conserve energy and natural resources, to reduce the amount of waste generated, and to ensure that wastes are managed in an environmentally sound manner.

Resource Conservation and Recovery Information System (RCRIS). Is a database that provides information about specific sites through the EPA Envirofacts website.

Secondary Maximum Contaminant Levels (SMCL). The maximum concentration of a substance in water that is recommended to be delivered to users of a public water supply based on aesthetic qualities. SMCLs are non-enforceable guidelines for public water supplies, set by EPA under authority of the Safe Drinking Water Act. Compounds with SMCLs may occur naturally in certain areas, limiting the ability of the public water supply to treat for them.

Section Seven Tracking System (SSTS). SSTS is an automated system EPA uses to track pesticide producing establishments and the amount of pesticides they produce.

Source Water. Any surface water, spring, or ground water source that provides water to a public water supply.

Source Water Delineation and Assessment Report (SWDAR). A report for a public water supply that delineates source water protection areas, provides an inventory of potential contaminant sources within the delineated areas, and evaluates the relative susceptibility of the source water to contamination from the potential contaminant sources under “worst-case” conditions.

Source Water Protection Areas. For surface water sources, the land and surface drainage network that contributes water to a stream or reservoir used by a public water supply. For ground water sources, the area within a fixed radius or three-year travel time from a well, and the land area where the aquifer is recharged.

Spill Response Region. A source water management area for surface water systems that encompasses the area expected to contribute water to a public water supply within a fixed distance or a specified four-hour water travel time in a stream or river.

Standard Industrial Classification (SIC) Code. A method of grouping industries with similar products or services and

assigning codes to these groups.

Static Water Level (SWL). Water level elevation in a well when the pump is not operating.

Susceptibility (of a PWS). The relative potential for a PWS to draw water contaminated at concentrations that would pose concern. Susceptibility is evaluated at the point immediately preceding treatment or, if no treatment is provided, at the entry point to the distribution system.

Synthetic Organic Compounds (SOC). Man made organic chemical compounds (e.g. herbicides and pesticides).

Total Dissolved Solids (TDS). The dissolved solids collected after a sample of a known volume of water is passed through a very fine mesh filter.

Total Maximum Daily Load (TMDL). The total pollutant load to a surface water body from point, nonpoint, and natural sources. The TMDL program was established by section 303(d) of the Clean Water Act to help states implement water quality standards.

Toxicity. The quality or degree of being poisonous or harmful to plants, animals, or humans.

Toxicity Characteristic Leachate Procedure. A test designed to determine whether a waste is hazardous or requires treatment to become less hazardous.

Toxic Release Inventory (TRI). An EPA database that compiles information about permitted industrial releases of chemicals to air and water. Information about specific sites can be obtained through the EPA Envirofacts website.

Transmissivity. A number that describes the ability of an aquifer to transmit water. The transmissivity is determined by multiplying the hydraulic conductivity time the aquifer thickness.

Turbidity. The cloudy appearance of water caused by the presence of suspended matter.

Unconfined Aquifer. An aquifer containing water that is not under pressure. The water table is the top surface of an unconfined aquifer.

Underground Storage Tanks (UST). A tank located at least partially underground and designed to hold gasoline or other petroleum products or chemicals, and the associated plumbing system.

Volatile Organic Compounds (VOC). Chemicals such as petroleum hydrocarbons and solvents or other organic chemicals which evaporate readily to the atmosphere.

Watershed. The land area that drains into a stream; the watershed for a major river may encompass a number of smaller watersheds that ultimately combine at a common delivery point.

* With the exception of the definitions for Lacustrine, Phase II and Phase V Rules, and Standard Industrial Classification Code, definitions were adapted from EPA’s Term References System (formerly known as Glossary of Selected Terms and Abbreviations) which can be found at: http://www.epa.gov/trs/index.htm

The definitions of glacial and lacustrine were taken from the Glossary of Geology by Robert L. Bates and Julia A. Jackson.

The definitions for Phase II and Phase V Rules were adapted from: http://www.epa.gov/OGWDW/source/therule.html#PhaseII http://www.epa.gov/OGWDW/source/therule.html#PhaseV

The definition for Standard Industrial Classification Code was adapted from: EPA/Office of Enforcement and Compliance Assurance: Guide to Environmental Issues: Glossary of Terms & Acronyms APPENDICES

APPENDIX A: Site Layout

APPENDIX B: Well Logs

Montana Bureau of Mines and Geology Ground-Water Information Center Site Report WHITETAIL SEWER AND WATER (Well #1)

Location Information GWIC Id: 34534 Source of Data: LOG Location (TRS): 21N 02E 34 CBD Latitude (dd): 47.5284 County (MT): CASCADE Longitude (dd): -111.4702 DNRC Water Right: Geomethod: TRS-TWN PWS Id: Datum: NAD27 Block: Altitude (feet): 3340.00 Lot: Certificate of Survey: Addition: Type of Site: WELL

Well Construction and Performance Data Total Depth (ft): 199.00 How Drilled: CABLE Static Water Level (ft): 2.00 Driller's Name: BYRNE Pumping Water Level (ft): 30.00 Driller License: WWC135 Yield (gpm): 65.00 Completion Date (m/d/y): 3/17/1976 Test Type: BAILER Special Conditions: Test Duration: 1.00 Is Well Flowing?: Drill Stem Setting (ft): Shut-In Pressure: Recovery Water Level (ft): Geology/Aquifer: Not Reported Recovery Time (hrs): Well/Water Use: PUBLIC WATER SUPPLY Well Notes: Hole Diameter Information Casing Information1

From To Diameter Wall Pressure 0.0 199.0 8.0 From To Dia Thickness Rating Joint Type 0.0 199.0 8.0 32 LB Annular Seal Information Completion Information1

No Seal Records currently in GWIC. # of Size of From To Dia Openings Openings Description 199.0 199.0 8.0 OPEN BOTTOM

Lithology Information From To Description 0.0 2.0 TOPSOIL 2.0 23.0 SANDY SOIL 23.0 28.0 SAND AND WATER 28.0 35.0 BROWN SILT 35.0 160.0 GRAY SILT 160.0 177.0 BROWN SILT 177.0 182.0 SAND AND WATER 182.0 199.0 SAND GRAVEL AND WATER

1 - All diameters reported are inside diameter of the casing.

Montana Bureau of Mines and Geology Ground-Water Information Center Site Report WHITETAIL WATER AND SEWER (Well #2)

Location Information GWIC Id: 34537 Source of Data: LOG Location (TRS): 21N 02E 34 CBD Latitude (dd): 47.5284 County (MT): CASCADE Longitude (dd): -111.4702 DNRC Water Right: Geomethod: TRS-TWN PWS Id: Datum: NAD27 Block: Altitude (feet): 3340.00 Lot: Certificate of Survey: Addition: Type of Site: WELL

Well Construction and Performance Data Total Depth (ft): 192.00 How Drilled: CABLE Static Water Level (ft): 2.00 Driller's Name: BYRNE Pumping Water Level (ft): 32.00 Driller License: WWC135 Yield (gpm): 100.00 Completion Date (m/d/y): 12/26/1975 Test Type: BAILER Special Conditions: Test Duration: 1.00 Is Well Flowing?: Drill Stem Setting (ft): Shut-In Pressure: Recovery Water Level (ft): Geology/Aquifer: 112ALVM Recovery Time (hrs): Well/Water Use: PUBLIC WATER SUPPLY Well Notes: WELL NO 8 Hole Diameter Information Casing Information1

From To Diameter Wall Pressure 0.0 192.0 8.0 From To Dia Thickness Rating Joint Type 0.0 192.0 8.0 32 LB Annular Seal Information Completion Information1

No Seal Records currently in GWIC. # of Size of From To Dia Openings Openings Description 192.0 192.0 8.0 OPEN BOTTOM

Lithology Information From To Description 0.0 25.0 TOPSOIL 25.0 29.0 SAND GRAVEL AND WATER 29.0 172.0 GRAY SILT 172.0 179.0 BLACK QUICKSAND 179.0 192.0 SAND GRAVEL AND WATER

1 - All diameters reported are inside diameter of the casing.

Montana Bureau of Mines and Geology Ground-Water Information Center Site Report WHITETAIL WATER AND SEWER (Well #4)

Location Information GWIC Id: 34539 Source of Data: LOG Location (TRS): 21N 02E 34 CBD Latitude (dd): 47.5284 County (MT): CASCADE Longitude (dd): -111.4702 DNRC Water Right: Geomethod: TRS-TWN PWS Id: Datum: NAD27 Block: Altitude (feet): 3340.00 Lot: Certificate of Survey: Addition: Type of Site: WELL

Well Construction and Performance Data Total Depth (ft): 193.00 How Drilled: CABLE Static Water Level (ft): 0.00 Driller's Name: BYRNE Pumping Water Level (ft): 30.00 Driller License: WWC135 Yield (gpm): 90.00 Completion Date (m/d/y): 1/23/1976 Test Type: BAILER Special Conditions: Test Duration: 1.00 Is Well Flowing?: Drill Stem Setting (ft): Shut-In Pressure: Recovery Water Level (ft): Geology/Aquifer: 112ALVM Recovery Time (hrs): Well/Water Use: PUBLIC WATER SUPPLY Well Notes: WELL NO 10 Hole Diameter Information Casing Information1

From To Diameter Wall Pressure 0.0 193.0 8.0 From To Dia Thickness Rating Joint Type 0.0 193.0 8.0 32 LB Annular Seal Information Completion Information1

No Seal Records currently in GWIC. # of Size of From To Dia Openings Openings Description 193.0 193.0 8.0 OPEN BOTTOM

Lithology Information From To Description 0.0 35.0 TOPSOIL 35.0 45.0 SAND AND WATER 45.0 100.0 PURE SAND 100.0 179.0 GRAY SILT 179.0 193.0 SAND GRAVEL AND WATER

1 - All diameters reported are inside diameter of the casing.

These data represent the contents of the GWIC databases at the Montana Bureau of Mines and Geology at the time and date of the retrieval. The information is considered unpublished and is subject to correction and review on a daily basis. The Bureau warrants the accurate transmission of the data to the original end user. Retransmission of the data to other users is discouraged and the Bureau claims no responsibility if the material is retransmitted. Note: non-reported casing, completion, and lithologic records may exist in paper files at GWIC.

Montana Bureau of Mines and Geology Plot this site on a topographic map Ground-Water Information Center Site Report SUN PRARIE VILLAGE COUNTY WATER AND SEWER DISTRICT (#8)

Location Information GWIC Id: 167886 Source of Data: LOG Location (TRS): 21N 02E 34 CBA Latitude (dd): 47.5303 County (MT): CASCADE Longitude (dd): -111.4702 DNRC Water Right: P006853-00 Geomethod: TRS-TWN PWS Id: Datum: NAD27 Block: Altitude (feet): Lot: Certificate of Survey: Addition: Type of Site: WELL

Well Construction and Performance Data Total Depth (ft): 204.00 How Drilled: ROTARY Static Water Level (ft): 9.50 Driller's Name: CENTRAL Pumping Water Level (ft): 100.00 Driller License: WWC581 Yield (gpm): 750.00 Completion Date (m/d/y): 11/8/1997 Test Type: AIR Special Conditions: Test Duration: Is Well Flowing?: Drill Stem Setting (ft): Shut-In Pressure: Recovery Water Level (ft): 10.00 Geology/Aquifer: Not Reported Recovery Time (hrs): 0.25 Well/Water Use: PUBLIC WATER SUPPLY Well Notes: Hole Diameter Information Casing Information1

From To Diameter Wall Pressure 0.0 18.5 16.0 From To Dia Thickness Rating Joint Type STEE 18.5 197.0 13.0 -2.0 182.0 10.0 L 197.0 204.0 10.0 STEE -2.0 199.0 8.0 L STEE -1.5 18.5 16.0 L Annular Seal Information Completion Information1

From To Description # of Size of 0.0 182.0 BENTONITE From To Dia Openings Openings Description 199.0 202.0 6.0 SCREEN

Lithology Information From To Description 0.0 28.0 SAND AND GRAY CLAY 28.0 177.5 DARK GRAY CLAY 177.5 184.0 HARD TO MED HARD BLACK SAND 184.0 202.0 GRAVEL WITH HEAVING SAND COARSER CLEANER GRAVEL 200 TO 202 202.0 204.0 GRAY SANDSTONE CARBONATIOUS

1 - All diameters reported are inside diameter of the casing.

APPENDIX C: Water Use Statistics

APPENDIX D: Concurrence Letter