CANYON FERRY VILLAGE PUBLIC WATER SYSTEM

PWSID# MT0000243

SOURCE WATER DELINEATION AND ASSESSMENT REPORT

Report Date: 10/23/03

Contact Person:

Budd Breining Canyon Ferry Village – Bureau of Reclamation 7661 Canyon Ferry Road Helena, MT 59601

Phone: (406) 475-3310

Table of Contents

SECTION Page INTRODUCTION...... 1 PURPOSE ...... 1 LIMITATIONS ...... 1 PUBLIC WATER SUPPLY INFORMATION...... 1 GEOGRAPHY...... 2 GEOLOGY ...... 3 WATER QUALITY ...... 3 DELINEATION...... 3 INVENTORY...... 4 SUSCEPTIBILITY ASSESSMENT ...... 4 TABLE 1: HAZARD RANKINGS OF SIGNIFICANT POTENTIAL CONTAMINANT SOURCES IN THE CANYON FERRY VILLAGE PWS INVENTORY REGION...... 4 TABLE 2: SUSCEPTIBILITY ASSESSMENT RATINGS OF SIGNIFICANT POTENTIAL CONTAMINANT SOURCES IN THE CANYON FERRY VILLAGE PWS INVENTORY REGION...... 5 SUMMARY...... 5 REFERENCES ...... 6 APPENDICES ...... 7 APPENDIX A: AREA WELLS...... 8 APPENDIX B: SITE LAYOUT ...... 9 APPENDIX C: CONCURRENCE LETTER...... 10

FIGURES

FIGURE 1. CANYON FERRY VILLAGE VICINITY MAP FIGURE 2. CANYON FERRY VILLAGE WELL LOCATION MAP FIRUGE 3. CANYON FERRY VILLAGE REGIONAL GEOLOGY FIGURE 4. CANYON FERRY VILLAGE INVENTORY REGION FIGURE 5. CANYON FERRY VILLAGE REGIONAL LAND USE

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Source Water Delineation and Assessment Report for Canyon Ferry Village (PWSID# MT0000243)

Introduction

Carolyn DeMartino, a Water Quality Specialist with the Montana Department of Department of Environmental Quality (DEQ), and Amy C. Schlatter, a DEQ intern, completed the Canyon Ferry Village Source Water Delineation and Assessment Report.

Purpose

The Canyon Ferry Village Public Water System (PWS) Source Water Delineation and Assessment Report has been completed to meet the technical requirements of 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 protecting public drinking water supplies from contamination. A major component of the 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.

Limitations

The terms “drinking water supply” or “drinking water source” refer specifically to the source of Canyon Ferry Village public water supply and not to any other public or private water supply. Also, not every potential or existing source of groundwater or surface water contamination in the area has been identified. Identification of potential contaminant sources is limited to those regulated for this class of PWS and is generally based on readily available information and reports. Every effort has been made to ensure completeness, however, unregulated activities and unreported contaminant releases may have been overlooked.

The delineation method utilizes simplifying assumptions that may not fully represent complex ground water flow systems but is intended to be conservative and protective of public health.

Public Water Supply Information

The Canyon Ferry Village PWS, a transient non-community public water supply, is located on the northeast corner of Canyon Ferry Lake, just 1.2 miles east of Canyon Ferry Dam (Figure 1). The legal location is SW1/4NE1/4NW1/4, Section 3, T.10 N., R.1W. (Figure 2). The Canyon Ferry Village PWS has discontinued the use of surface water

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currently utilizes one groundwater well, Well #2 (WL004), to supply water through five service connections to the Bureau of Reclamation office, a warehouse, garage, carpenter shop, and the visitors center The PWS serves a transient population of 25 people in the summer (DEQ SDWIS Database, 2003). There is no available well log or water rights record for this well at either the Montana Bureau of Mines and Geology (MBMG) Ground Water Information Center (GWIC) or the Department of Natural Resources and Conservation (DNRC).

Information for Well #2 is based on information provided by Budd Breining, the water operator, a sanitary survey completed in October 2001 by the Cadmus Group, an Operation and Maintenance Evaluation from January 1995, and the DEQ SDWIS database. This PWS is supplied by one well with a 6-inch casing and submersible pump. According to Budd Breining, six fiberglass pressure tanks control the cycling of the well pump and provide 85 gallons of storage each with 35 gallons of drawdown capacity. The water runs through two small filters, in parallel, for sand removal and then is chlorinated with sodium hypochlorite. (Cadmus, 2001). According to the 1995 Operation and Maintenance Evaluation, the well yield is 50 gallons per minute (gpm). Well depth and lithology are unknown. Based on another area well log, the well appears to be completed in semi-confined Tertiary sediments that are overlain by Quaternary sediments (Appendix A). The source water sensitivity to potential contaminant sources for this aquifer type is moderate.

An estimated water demand of 250 gallons per day (gpd) in the summer was determined for this PWS by referencing the water usage value of 10 gpd for the transient population (EPA, 1991). The water demand during winter months is 50 gallons per day (B. Breining, September 2003).

Geography

The Canyon Ferry Village PWS is located on the northeast side of Canyon Ferry Lake approximately 20 miles east of Helena. Canyon Ferry Lake was created when Canyon Ferry Dam was constructed on the Missouri River near the small settlement of Canyon Ferry. The Big Belt Mountains bound the Missouri River Valley to the northeast and the Spokane Hills bound the valley on the southwest side. Prominent river-cut terraces are present at several levels (Mertie, Fischer, and Hobbs, 1951).

Climate in the Canyon Ferry Lake area is considered semi-arid. The average monthly high and low temperatures in the vicinity range from 84.0° F to 52.2° F in July and 31.3° F to 13.6° F in January. Precipitation averages 11.36 inches annually concentrated in the months May through September. Looking at historic snowfall data, it appears that snowfall in the Canyon Ferry Village area ranges between 26 to 38 inches annually (WRCC).

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Geology

Sedimentary rocks in the Canyon Ferry Lake area are comprised of rocks that range in age from Precambrian to Recent (Figure 3). The Precambrian rocks are composed of limestone and shale of the Belt Series. Tertiary lake deposits in the area are composed of volcanic debris. Recent-aged (Quaternary) river alluvium consisting of gravel, sand, and silt are found on the valley floor. Igneous rocks consisting of monzonite and granite that intruded sedimentary deposits are most likely Tertiary-aged. Lava flows and basalt dikes were intruded during the Miocene epoch. Historically, some copper, gold, and platinum mining occurred in the Canyon Ferry Lake vicinity. Sapphires have also been mined in this vicinity. Most neighboring mines in the region have been abandoned. (Mertie, Fischer, and Hobbs, 1951).

Water Quality

The Canyon Ferry Village PWS is classified as a transient non-community public water supply; therefore, the only regulated contaminants that are required to be routinely monitored in the drinking water include nitrate and microbial pathogens. In the last five years, nitrate plus nitrite levels in this public water supply well ranged between 0.0 milligrams per liter (mg/L) to 0.52 mg/L (DEQ SDWIS database). These levels are well below the EPA mandated maximum contaminant level (MCL) of 10 mg/L.

Based on a review of the DEQ SDWIS drinking water database for this PWS, there have been no detections of coliform bacteria in the past five years. Coliform bacteria are naturally occurring in the environment and while they are not considered a health threat in themselves; they are indicators that harmful bacteria like fecal coliforms are present in the water. Fecal coliforms are bacteria that are associated with human or animal wastes. They usually live in human or animal intestinal tracts, and their presence in drinking water is a strong indication of recent sewage or animal waste contamination. Fecal coliform bacteria cause concern because they can include E. coli, which is a serious threat to human health (EPA 2003).

Delineation

A 100-foot fixed radius control zone and a modified 1-mile fixed radius inventory region (Figure 4) were delineated around the Canyon Ferry Village PWS well as required for a transient, non-community PWS under the Montana Source Water Protection Program (DEQ, 1999). The 100-foot radius control zone surrounding the wellhead is the most critical area in which direct introduction of contaminants into the well or the immediate area can occur. The modified one-mile inventory region encompasses the areas that water or contaminants can flow to Well #2 over a period of months to years depending on flow velocity and well pumping capacity.

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Inventory

The Montana Source Water Protection Program (DEQ, 1999) requires that land uses and all potential sources of nitrate and microbial pathogens be identified within the control zone and inventory region of a semi-confined, transient, non-community public water system. Note, that other potential contaminant sources, such as underground storage tanks may be located within the control zone and inventory region but are not considered as regulated potential contaminant sources because this is classified as a transient non- community PWS.

An upper warehouse building owned by the U.S. Bureau of Reclamation is located within 30 feet of Well #2. The site layout for Canyon Ferry Village is located in Appendix B. Additional land uses within the 1-mile radius inventory region around the well include evergreen forest (51%), grassland (33%), shrubland (7%), woody wetlands (3%), and transportation routes (Figure 5). Canyon Ferry Village utilizes four on-site septic systems to treat and dispose of sanitary wastes. These are located beside the warehouse and across the road in the lawn of the visitors center, east of the office building, and in the park across the road from the long white buildings that house the carpenter shop and garage (Granthan, 2003). The overall septic density in the inventory region is classified as low (NRIS).

The most significant potential contaminant sources of nitrate and pathogens in the inventory region include the four on-site septic systems. Nitrates and pathogens could leach from the on-site septic systems and allow effluent to migrate into area groundwater as it travels down gradient towards the lake.

Susceptibility Assessment

The proximity of a potential contaminant source to a well or the density of non-point potential contaminant sources determines the threat of contamination, referred to as hazard. For the purpose of this assessment, the hazard ranking for the on-site septic systems within the inventory region is based on their distance down gradient from the well. The information is presented in Table 1.. TABLE 1: HAZARD RANKINGS OF SIGNIFICANT POTENTIAL CONTAMINANT SOURCES IN THE CANYON FERRY VILLAGE PWS INVENTORY REGION.

Potential Contaminants Description Hazard Rating Contaminant Source On-site Nitrates and pathogens Potential leakage of untreated Low Septic effluent into area groundwater and Systems surface water due to system failure

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Hazard and the existence of barriers to prevent contamination determine the susceptibility of an aquifer to potential contamination. Barriers can be engineered, management actions, or natural. Examples of engineered barriers are spill containment structures for industrial facilities and leak detection for underground storage tanks. Examples of management barriers include the adoption of local ordinances to keep potential contaminant sources out of the control zone for wells, completion of a emergency response plan, or the use of best management practices to manage particular potential contaminant sources. Clay rich soils or a laterally continuous clay layer are examples of natural barriers.

Based on the well log of a nearby well, the clay layers identified in the sub-surface lithology may act as barriers and prevent potential contaminants from reaching the aquifer. Also, the Canyon Ferry Village well is located upgradient from the septic systems and therefore groundwater flow direction is most likely a barrier against contamination. There are no other known barriers at this time. Table 2 identifies the susceptibility ranking for each potential contaminant source in the inventory region and also includes management recommendations for these potential contaminant sources. If implemented, these management recommendations may be considered barriers. If a well log is provided to DEQ, this may help determine any additional barriers and can be used in a reassessment of the susceptibility rating.

TABLE 2: SUSCEPTIBILITY ASSESSMENT RATINGS OF SIGNIFICANT POTENTIAL CONTAMINANT SOURCES IN THE CANYON FERRY VILLAGE PWS INVENTORY REGION.

Potential Hazard Source Barriers Susceptibility Recommendations Contaminant Rating Groundwater On-Site Septic Nitrate and Conduct regular Low flow direction, Very low Systems Pathogens maintenance Clay layers

Summary

This report was prepared to assist the water operator for the Canyon Ferry Village PWS to understand the public water system for which they are responsible. The report provides information concerning the aquifer that supplies water to the well and identifies the control zone and inventory regions. Within each of these protection areas the significant potential contaminants that may impact the well water are also identified. Also provided in the Table 2 are recommendations regarding how the potential source of nitrates and pathogenic contaminants could be managed to prevent impacts to Canyon Ferry Village Well #2.

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References

Cadmus Group, Inc, October 2001, Sanitary survey of The Canyon Ferry Village public water system (PWSID: 00243). Completed by Maureen Donnelly.

EPA, 2003, Ground Water and Drinking Water, Consumer Fact sheet on Nitrates/Nitrites.

EPA, 1991, Office of Water, Manual of Small Public Water Supply Systems, EPA, 571/9-91-003, 221 p.

Granthan, Pat, 6/18/03, telephone interview.

Mertie, John B., Fischer, Richard P., and Hobbs, S. Warren, 1951, Geology of the Canyon Ferry Quadrangle, Montana, United States Geological Survey Bulletin 972.

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

Montana Bureau of Mines and Geology Ground Water Information Center (GWIC), Butte, Montana

Montana Department of Environmental Quality, 1999, Montana Source Water Protection Program, Approved by EPA in November, 1999.

Montana Department of Natural Resources and Conservation, Water Resources Division, Water Rights Bureau, Helena, Montana.

Montana Natural Resource Information System, Spatial Query and Mapping System (NRIS).

Pagel, Craig W., Operation and Maintenance Evaluation of the Canyon Ferry Dam Public Water Supply; PWSID #00243, January 1995, Montana Department of Health and Environmental Sciences, Water Quality Division.

Ross, Clyde P., Andrew, Daniel A., Witkind, Irving, 1955, Geologic Map of Montana, Montana Bureau of Mines and Geology.

Western Regional Climate Center, [email protected], Montana Climate Summaries, Canyon Ferry Dam, Montana (241470). Period of Record : 12/28/1907 to 7/31/1996.

U.S. Geological Survey, 2000, National Land Cover Dataset, Montana.

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Appendices

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APPENDIX A: AREA WELLS

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APPENDIX B: SITE LAYOUT

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APPENDIX C: CONCURRENCE LETTER

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