Funding in Place for Monroe County Water Study
In October 2016, the U.S. Geological Survey (USGS) received a referral from Mike Hohn the Director and State Geologist for the West Virginia Geological and Economic Survey (WVGES), that resulted from a letter drafted by the Monroe County Commission to Cabinet Secretary Keith Burdette. The letter requested that the West Virginia Geological and Economic Survey:
- Undertake and complete a thorough mapping and study of the complex karst region at the base of Peters Mountain and other areas of karst on or near the Mountain Valley Pipeline proposed corridor, and
- Conduct an independent, comprehensive hydrogeological study of the water resources of Monroe County.
It was recently announced that the project is now fully funded in the amount of $360,000; with monies for the study being provided by the WV Department of Environmental Protection, the United States Geological Survey, and the Source-Water Protection Program operated by DHHR’s Bureau of Public Health.
In regard to the study, Mark Kozar, of the U.S. Geological Survey, noted: “The Greenbrier aquifer is one part of the State that the USGS has not been afforded much opportunity to study, at least from a hydrogeologic perspective. As the Greenbrier aquifer is one of the larger and more important karst aquifers in the State of West Virginia, better characterization of the hydrogeology of the aquifer to aid understanding of groundwater flow processes is imperative, and a high priority for the USGS Virginia and West Virginia Water Science Center. Since the issue is also important to County planners, we are optimistic about moving forward in our studies of the Greenbrier aquifer, beginning in Monroe County, and potentially in future years expanding our studies northward to Greenbrier and Pocahontas Counties.”
The following information is excerpted from the Project Proposal, as prepared by Mark D. Kozar, Mitchell A. McAdoo, and Kurt J. McCoy, of the US Geological Survey.
Groundwater resources are vital to the rural communities of Monroe County, and a majority of County residents and public water systems rely on groundwater as their primary water source. The County has also experienced economic growth over the last 40 years, and projections are that economic growth will continue at an increased rate in the future. Assessing water availability within Monroe County and better understanding groundwater flow processes within the fractured rock and karst aquifers of Monroe County is essential for wise management and protection of the valuable groundwater resource upon which the County depends as a source of water for residential, agricultural, and public supply
The goal of this proposal is to build a coalition of Federal, State, County, and local agencies and the U.S. Geological Survey (USGS) interested in mapping and characterizing groundwater in Monroe County, with particular emphasis on assessing the hydrogeology and groundwater resources of the Mississippian and Ordovician karst aquifers. The purpose of the hydrogeologic assessment is to supply Monroe County with information to make science-based decisions on water-resources supply and management. Potential cooperative agencies may include the U.S. Geological Survey (USGS), the West Virginia Geological and Economic Survey (WVGES), the West Virginia Department of Health and Human Resources (WVDHHR), the West Virginia Department of Environmental Protection (WVDEP), the Monroe County Commission, the Appalachian Regional Commission, the City of Union, and private entities within Monroe County.
Karst aquifers comprised of the Mississippian Greenbrier and Ordovician Beekmantown, St. Paul, Trenton, and Black River limestone Groups underlie the central and eastern portions of Monroe County and supply water for residential, agricultural, municipal, and commercial uses (fig. 1). The occurrence of solution voids in these karst aquifers (various shades of pink on fig. 1) has resulted in numerous karst features such as caves, sinkholes, disappearing streams, and large karst springs that have been the focus of numerous studies conducted by the karst community and academia since the mid 1970’s. Siliclastic sandstone and shale aquifers of Silurian through Devonian (various shades of brown and green on fig. 1) and Mississippian age (various shades of blue on fig. 1) are also important sources of rural water supplies, and comprise much of the area of Monroe County in the southwest, northeast, and eastern portions of the County.
The overall objective of this proposed study is to develop hydrogeologic maps useful for active management of the groundwater resources in Monroe County. Interpretive maps inclusive of aquifer boundaries, water table elevations or potentiometric surfaces, and dye-trace results will provide additional insights into sources and sinks of groundwater and groundwater flow paths. Hydrogeologic mapping is intended to advance the conceptual understanding of the interconnectedness between the groundwater system and activities at the land surface. Specific objectives of the study are to:
(1) Develop a hydrogeologic framework for the karst and siliciclastic (non-karst) aquifers in Monroe County. A hydrogeologic framework consists of mapping bedrock extents, thicknesses, and hydrologic properties of aquifers;
(2) Determine directions of groundwater flow by creating a regional potentiometric surface map or maps of groundwater levels. Potentiometric surface mapping will be given increased emphasis for the Mississippian and Ordovician karst aquifers. If time, funding, and well density are sufficient, potentiometric surface maps may be developed for select areas within the siliciclastic Ordovician through Mississippian age sandstone and shale rock aquifers in the county;
(3) Develop groundwater budgets for both the karst and siliciclastic aquifers in Monroe County. Groundwater budgets are used to define the volumes or rates of water flowing into and out of aquifers;
(4) Document rates and directions of groundwater flow for those areas lacking such data by conducting a series of dye tracer-tests to assess contribution of specific points of input to the groundwater system and better delineate source-water protection areas for select public supply springs and wells. Dye tracing also provides information which can be used to provide information about persistence of potential contaminants which could threaten public water systems in Monroe County should there be a contaminant release; and
(5) Assess the depth of solution development in karst areas, characterize fracture and bedding controls on groundwater flow processes, and develop a better conceptual understanding of the groundwater flow system by collecting, compiling and interpreting borehole geophysical log data. Some borehole geophysical tests will be conducted as part of an existing statewide assessment, but additional borehole geophysical tests in Monroe County are planned for this project.
A combination of digital compilation and field-based efforts are required to help develop a hydrogeologic framework which may be used to better understand, manage, and protect the groundwater resources of Monroe County.
(1) Hydrogeologic Framework — Development of the hydrogeologic framework for Monroe County will be completed by:
a. Digitizing water-bearing formations, springs, sinkholes, sinking streams, and dye tracer tests within the Mississippian Greenbrier (Ogden, 1976; Jones, 1997) and Ordovician Beekmantown karst aquifers
b. Depicting general locations of caves and spring discharges (Dasher, 2012)
c. Using LiDAR (digital elevation models) to define aquifer thickness (isopach maps) and map potential sinkhole locations.
d. Incorporating structure contour maps for the Greenbrier Group and other data available from the West Virginia Geologic and Economic Survey
(2) Directions of Groundwater Flow (Potentiometric surface mapping) – Water levels will be measured in wells within select areas of Monroe County to define depths to the groundwater table and direction of groundwater flow within Mississippian and Ordovician karst aquifers and for select areas within the siliciclastic sandstone and shale aquifers of Ordovician through Mississippian age. In areas with sufficient wells available to develop accurate maps, potentiometric surfaces will be derived from field data. An attempt will be made to measure 200 and 300 water-levels from domestic and monitoring wells, but the eventual number of water-level measurements will depend on the density of wells available for measurement in respective areas of Monroe County. It may not be practical to develop potentiometric surface maps for all areas of the County due to a lack of wells in certain areas.
(3) Rates of groundwater flowing into and out of aquifers — Groundwater budget analysis will be summarized for each aquifer in Monroe County by use of existing Soil-Water Balance model results. Precipitation data has been used with topographic and soils data to determine groundwater recharge, surface runoff, base flow, and evapotranspiration. A single base-flow seepage survey of streams across the County is planned to verify the spatial variability in base flow groundwater discharge depicted by the Soil-Water-Balance model.
(4) Assessment of groundwater flow velocities and potential for contamination — Dye tracer tests will be conducted by using Rhodamine WT, Fluorescein, or other fluorescent dyes to assess directions and rates of groundwater flow and potential recharge areas of important public drinking water supplies in Monroe County, including the town of Union. Results of dye tracer tests in conjunction with hydraulic gradients derived from the potentiometric surface maps will be used to better assess source-water protection areas for specific public supplies of concern, and to assess rates and directions of groundwater flow.
(5) Characterization of fracture and bedding controls — Borehole geophysical logging of a maximum of 20 to 25 wells is planned as part of this proposed assessment and a separate existing statewide borehole logging effort. Logs will be analyzed to assess local scale fracture- and bedding-controls on groundwater flow that can be up scaled to enhance aquifer mapping of prominent fracture zones.
It is anticipated that development of the potentiometric surface, hydrogeologic, and dye tracer test maps as would take 2 years to complete. All data collected and non-interpretive maps developed for the project will be published and made available for public access as a USGS Data Release through the USGS Science Base repository. The fourth year of the study would be devoted primarily to writing an interpretative USGS Scientific Investigations Report.
BENEFITS AND FEDERAL ROLE
Completion of the proposed work will provide the USGS with additional groundwater and surface-water data for a poorly understood karst area in West Virginia. These data will add to the USGS national database and will assist in understanding and describing the Nation’s water resources. This study aligns with the 2016 priorities for the Cooperative Water Program, including “data collection–enhance hydrologic-data networks for improved hazards protection and forecasting and to support assessments of water sustainability for human and ecological needs” and “assessments and tracking of water use, consumptive use, and water availability (Water Availability and Use Science).” This investigation will establish a baseline of aquifer status for fractured-rock aquifers in Monroe County, West Virginia. Groundwater resources are a treasured rural resource and a potential economic resource in the future development of the area. Investigations in the mid-1970’s through present (e.g. Dasher, 2012) focused on the karst aspects of Monroe County and little data are available to support management decisions elsewhere in the County. The inventory of aquifer conditions in Monroe County provided by this study will be important for assessment of source waters to public supplies where regional geologic structure may significantly influence the understanding of areas contributing to localized withdrawals. This study will build on the USGS research recently completed in the Shenandoah Valley (Kozar and others, 2006) and Appalachian Plateaus (McCoy and others, 2015) by applying the concepts developed in those studies, to further research the complex hydrogeology of fractured-rock aquifers in areas facing land-use change. Data collected as part of this study have transfer potential to similar karst aquifers elsewhere in the Appalachian Plateaus and Valley and Ridge Physiographic Provinces within the Appalachian Mountain Region between Alabama and Maine.
This study will require over the 3-year course of the project two Hydrologists, a Geographer, a Geologist, and one or more Hydrologic Technicians part time to complete.
TIME FRAME AND DELIVERABLE PRODUCTS
It is anticipated that development of the potentiometric surface and hydrogeologic maps as a USGS Digital Data Series would take 3 years to complete. Collection of water-level, stream and major spring-flow discharge data, completion of dye tracer-tests and borehole geophysical surveys would be conducted in the 1st and 2nd years of the study. The USGS on-line data release and associated Arc-GIS database would be completed in the 3rd year of the project. The 4th year of the study would be devoted primarily to writing an interpretative USGS Scientific Investigations Report to summarize the findings and of the study.