West Manheim Township Groundwater Survey

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    Information is posted here on the results of a well survey project involving Jones Geological Services (JGS), United States Geologic Survey (USGS) and York County Conservation District (YCCD).  

    The survey's goals are to establish a basic idea of the water table in West Manheim Township.  With the use of staff and volunteers, approximately 60 wells were inventoried in early August.  The three teams visited selected wells measuring the depth to the static water level.  Selected wells received water quality tests including specific conductance, pH and metals tests.  Results were presented to the Board of Supervisors in November.  

    JGS, USGS and YCCD want to thank the property owners who graciously allowed us to access their wells.  We would also like to thank the volunteers who spent two days in the heat collecting this data.

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Go Directly to MAPS

Go Directly to Geological Society of America Abstracts concerning the Township

Go Directly to Database

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Below is the report written by Jeri Jones and Kathrlyn Low about the project's findings and recommendations:

Introduction

In March, 2005, a cooperative proposal from the United States Geological Survey (USGS) and Jones Geological Services (JGS) was presented to the West Manheim Township Board of Supervisors. This 2005 study was an extension of a preliminary study by Jeri Jones in 2003. The 2003 study was a compilation of wells within the region and a general look at the geology and ground-water resources as reported by other investigators. Through a recommendation of the report, a more detailed study of wells within West Manheim Township (Township) was proposed. This report and the associated CD present the results of the 2005 study.

Acknowledgements

The investigators are grateful to the West Manheim Township Board of Supervisors for accepting the project. The project could not have been conducted without the assistance of Dennis Low of the USGS and his daughter Kathryn. Kathryn Low chose to participate in this study as a 2006 Susquenita High School science fair project. Dennis and Kathryn dedicated many hours to this project. Gary Peacock of the York County Conservation District (YCCD) provided vital field support in locating and surveying wells. Gary was also the volunteer coordinator for this project. Tim Pfaff of West Manheim Township made available drilling records and field experience. Township residents Robert Eckenrode and Deborah Maisli spent the two days of August 5 and 6, 2005 collecting water-level and water-quality data with the teams. Barry Stump of the Codorus Creek Watershed Association also assisted in the data collecting on August 5 and 6, 2005. The York County Planning Commission provided GIS coverage for the project.  Township resident Connie Martz contributed contact names who may be interested in participating in the well survey.

Method of Study

The main goals for the project were 1) locate and survey a minimum of 50 wells and springs to compile a potentiometric or water-table map; 2) conduct field (pH, specific conductance) water-quality measurements on selected wells or springs; 3) build a database that included information on wells drilled within the Township; 4) determine if the different lithologies influenced well yields; and, 5) determine if there are any areas of low well yields.

Well Inventory

In May, 2005, the USGS, YCCD and JGS began to locate wells and secure permission for later inventory and site visits. Wells were chosen either based on geographic location, having a driller’s card on file and/or contacts from friends. It should be noted, that areas within the Township being served by public water were not included in the well inventory. Also, it was discovered that few wells existed on property denoted as conservation lands. This limited the geographical coverage of the study.

As wells were selected, latitude and longitude, property owner information, history of drought information and other problems were obtained and recorded. Several wells outside of the Township were inventoried. These wells were included as they 1) provided additional control to the water-table map; 2) were located on a point of geologic interest; or 3) were part of a proposed housing development.

On evening of June 28, 2005, a volunteer meeting was held. This gathering was designed to introduce the project to any Township residents interested in assisting in the well inventory and provide an update to Township officials regarding the progress of the study. A visit to an area well to demonstrate how to measure water levels was also held.

Wells were inventoried on August 5 and 6, 2005 throughout the Township. Three teams were setup. Gary Peacock, Dennis Low, and Jeri Jones were team leaders. Home owners who were willing to have their well or spring included were contacted in advance and appointment times assigned. Static water levels were recorded and water samples collected from about 80 sites. Water samples were measured at the Township office by Kathryn Low for pH and specific conductance. About 35 samples were also packaged and transported to Dickinson College for analysis of selected metals

Database Building

Beginning in May, 2005, water-well driller records on wells within and near the Township were gathered. The following sources were used to gather this information:

Township permits and records

Pennsylvania Ground Water Information System database (Pennsylvania Topographic and Geologic Survey)

Ground-Water Site Information database(United States Geologic Survey)

Codorus State Park well records

All information was transferred into an Excel database and is included on the accompanying CD. A total of 422 water-well driller cards were recorded and utilized in evaluating well depth, casing length, depth to bedrock, yield, specific capacity. However, less than 40 percent (164 wells) were determined to have locations accurate enough to be plotted on a digital map.

General Geology

Metamorphic rocks underlie much of the Township. The Marburg Schist underlies about 90% of the Township. This unit is composed of a bluish-gray to silvery-green fine-grained schist. Within the Marburg Schist are quartzites and slate members. Stose and Stose (1944) mapped these separate from the schist. The quartzite member underlies the higher elevations within the southern portion of the Township. The quartzite is a green schistose, ferruginous quartz conglomerate with rounded fragments of quartz and slate with muscovite partings.

The slate member is a gray-to-black smooth splitting slate closely associated with the quartzitic layers.

Underlying the northwestern corner of the Township is the Harpers Formation. The Harpers Formation is a dark gray-to-green quartzose phyllite. Minor occurrences of quartzite have been observed within the Harpers Formation.

Two other rock units within the Township are the Antietam and Conestoga Formations. On the southern slope of Lake Marburg near Black Rock Road is a small exposure of the greenish-gray granular ferruginous quartzite belonging to the Antietam Formation. Underlying Lake Marburg is the Conestoga Formation which consists of a thin-bedded dark limestone.

A small diabase dike occurs in the western portion of the Township. This igneous rock intrudes the Marburg Schist and Harpers Formation. Fragments of diabase are seen on the surface near the corner of Grand Valley Road and Leppo Mill Road and along Beck Mill Road near Fairview Drive.

Bedrock and Ground Water

Metamorphic rocks like the Marburg Schist have no primary porosity or primary pore space (unlike sand or gravel deposits). This has been eliminated by a history of heating and pressure which formed differing minerals and textures and eliminated voids by compaction and re-crystallization (metamorphism). Tectonic processes (mountain building) created many secondary openings such as fractures, faults, and voids and, at the same time, locally sealed some of these features.

Despite a complex history, the Township’s bedrock aquifers can be viewed from a broad hydrologic perspective. Water moves through, and is stored in, open fractures, faults, voids, joints, and bedding planes. The size, number, and distribution, and degree of interconnection of these secondary openings are highly variable. When present, water-bearing zones generally decrease in size and number with depth. In the Township wells typically penetrate only two water-bearing zones and over half of the water-bearing zones are penetrated by a depth of 90 feet. Thus, the overall storage capacity of bedrock is small and tends to decrease with depth.

The Marburg Schist is one of the lowest yielding aquifers in Pennsylvania. Wells that penetrate bedrock in the Township, however, can yield dependable supplies of water suitable for single-family domestic needs. The median yield of the Marburg Schist in the Township is 5 gallons per minute. Zones where bedrock is extensively fractured may yield larger quantities of water.

Because ground-water flow processes in fractured crystalline bedrock are complex, developing a more complete understanding of these processes is difficult. In general, ground water is stored in the overlying soil and weathered bedrock (regolith) and migrates slowly over time into the fractured bedrock where it is stored in secondary openings. Much of this water flows from hilltops to valleys where it is released as springs. A well penetrating this flow system acts as a short cut, and the water will commonly rise within the well. If a sufficiently large number of wells exist and the depths to water are measured, then a pressure or potentiometric map can be created that provides a general idea of ground-water flow. This is what most of the effort on August 5 and 6, 2005 was directed towards.

Poteniometric (Water Table) Map

In general, the potentiometric map shows that water table is a smoothed reflection of the topographic surface. The poteniometric map suggests also that ground-water flow paths are probably shallow and that water moves fairly rapidly from hilltop to valley bottom.

The water contour lines have an interval of 20 feet. The closer the lines are together, the steeper the ground water level is. Depth to water is greater on hilltops than in valleys. In general, depth to water on hilltops averages about 30-40 feet below land surface. In valleys and upland draws, depth to water averages about 10-20 ft below land surface. At least four wells had deeper than expected depths to water. These wells were probably just recently pumped prior to or during measurement.

Numerous red lines on the map represent lineaments. Lineaments are features identified from high altitude aerial photographs that may represent fractures in the bedrock or man-made features such as fence rows. In some cases, the orientation of lineaments reflects the structural geology of the area. Although some lineaments appear to reflect the topography and geology, there are no patterns that seem to dictate the flow of the ground water.

This map can not be used to predict how much water will be found or where to find water, again, due to the unpredictable behavior of ground water in metamorphic rocks.

What Was Determined?

Two areas with limited yields were tentatively identified. The areas are along Pa. Rte. 94 between The Mason-Dixon Line and Pleasant Hill and in the vicinity of the intersection of Frogtown Road and Musselman Road.

The median depth to water-bearing zones is 87 feet. The minimum depth is 5 feet and the deepest is 380 feet.

Median depth to bedrock is 14 feet with a maximum of 145 feet and minimum of 1 foot.

Median yield is 5 gal/min with a maximum of 100 gal/min.

High-yielding wells (+10 gal/min) can be located next to low-yielding wells (< 3 gal/min).

Water levels in wells range from a minimum of 2 to 124 feet below land surface.

Water levels can vary within a short distance and are affected by topography.

Ground-water flow paths appear to be relatively shallow.

Borehole storage (water sitting in the well bore) is an important resource for about 50 percent of the wells.

About half of the wells sampled contain water with a pH below the U.S. Environmental Protection Agency range of 6.5 – 8.5. This suggests aggressive water can be a major problem.

Well drillers like to set casing in 20-foot lengths. However, depth to bedrock also significantly affects the amount of casing used.

What Was Not Determined?

The affects of lithology on well yield.

The affects of lithology on pH and specific conductance.

Spatial trends or patterns in depth to bedrock, water-bearing zones, or well depth.

Spatial trends or patterns in yields or specific capacity.

Areas where high-yielding wells can be consistently found.

Association of lineaments to well yield or specific capacity.

More specific information can be found on the CD and attached tables.

High Priority Recommendations

As found in many municipalities, ground-water statistics, permitting and record keeping is a low priority. The Township made a major advancement during the summer of 2005 when they established an ordinance for obtaining well permits. During the preliminary work of compiling drilling cards and consultant reports, a large amount of time was spent verifying the location of wells. Out of 422 wells placed into the database, 164 were determined to have acceptable spatial coordinates so that the well could be visited and a latitude and longitude determined with an accuracy of 0.1 to 3 seconds.

The following are some recommendations that should be considered:

All wells should be visited by a Township official and verified via Global Positioning System.

All wells should have an aquifer test (pump the well at a known (i.e. measured) and suitable rate and measure the decline in water level) during which the Township official is present and takes notes.

All wells should have a minimum of water-quality done (bacteria, nutrients, some metals).

No well is approved until driller cards are in hand, engineer and hydrologist reports are in hand, and water-quality results are complete.

The Township should charge a $100 fee for the visit and associated paper work and filing. The water quality test should be charged to the developer/builder and sent to a USEPA/PADEP approved laboratory.

With the rapid developmental growth within the area, it is suggested a minimum well yield of 2 to 3 gal/min for any newly constructed well may be instituted.

If borehole storage [specific capacity is <0.03 (gal/min)/foot of drawdown represents a large component of flow from the well, additional storage should be constructed. This may be in the form of a deeper well or surface storage tank

The above suggestions are made to improve the record-keeping of the wells within the Township and to provide minimum standards to Township residents.

A secondary purpose of this study was to implement a volunteer corps who would go into the Township to take similar well readings in the future. A similar study may be conducted in 2007 in the same wells to measure the difference in water levels over time and collect some water quality data.

Equipment needed and purchased by the Township to meet the suggested recommendations would include:

At least one, and preferably two e-tapes to obtain water levels (cost per unit is ~ $500.

At least one, preferably two GPS units to record the latitudes and longitudes of well locations (cost per unit is ~ $225.

The above equipment should be purchased for a Township staff person to locate and inspect new wells as indicated above.

Other Recommendations

For further consideration, these points are suggested:

Install a monitoring well in a protected area where water levels can be measured on a weekly basis or placed online to collect data. A suggested location would be in the Sheppard-Meyers Reservoir area.

Implement a volunteer water quality test where residents would submit samples to a responsible party (Township or consultant) who would forward samples to a laboratory for bacteria and metals.

Establish a ground-water quality network

Hire a consultant or train Township personnel to conduct water-quality sampling and monitor aquifer tests.

Further Reading

Fleeger, G.M., 1999.  The Geology of Pennsylvania’s Groundwater.  Pa. Geol. Survey, 4th ser., Educational Ser. 3.

Fleeger, G.M., McElroy T.A., and Moore, M.E., 2004.  Hydrogeologic and well-construction characteristics of the rocks of Pennsylvania.  Pa. Geol. Survey, 4th ser., Water Res. Rept. 69.

Jones, J.L., 2003.  A preliminary look at the groundwater in West Manheim Township, York County, Pennsylvania.

Lloyd, O. B., and Growitz, D. J., 1977. Groundwater resources of central and southern York County, Pennsylvania. Pa. Geol. Survey, 4th ser., Water Res. Rept. 42.

Low, D.J., and Conger, R.W., 2002.  Ground-water availability in part of the Borough of Carroll Valley and the establishment of a drought-monitoring well.  U. S. Geol. Survey Water. Res. Rept.02-4273.

Low, D.L., and Dugas, D.L., 1999.  Summary of hydrogeologic and ground-water quality data and hydrogeologic framework at selected well sites, Adams County, Pennsylvania.  U.S. Geol. Survey Water Res. Investigations Rept. 99-4108.

Low. D.J., Hippe, D.J., and Yannacci, D., 2002.  Geohydrology of southeastern Pennsylvania.  U S. Geol. Survey Water Resources Invest. Report 00-4166.

Moore, J.E., Zaporozec, and Mercer, J.W., 1995. Groundwater – A Primer. American Geologic Institute Awareness Series: 1. Washington, D.C.

Stose, A.J., and Stose, G.W., 1944. Geology of the Hanover-York District Pennsylvania. U.S.G.S. Professional Paper 204.

Stose, G.W., 1932.  Geology and mineral resources of Adams County, Pennsylvania.  Pa. Geol. Survey, 4th ser., County Report 1.

Stose, G. W., and Jonas, A. I., 1939. Geology and mineral resources of York County, Pennsylvania. Pa. Geol. Survey, 4th ser., Bull. C 67.

Taylor, C.J,. and Alley, W.M., 2003.  Groundwater level monitoring and the importance of long=term water level data.  U.S.G.S. Circular 1217.

Taylor, L.E., and Royer, D.W., 1981.  Summary groundwater resources of Adams County, Pennsylvania.  Pa. Geol. Survey, 4th ser., Water Res. Report W 52.

Taylor, L.E., and Werkheiser, W.H., 1984.  Groundwater resources of the Lower Susquehanna River basin, Pennsylvania.  Pa. Geol. Survey, 4th ser., Water Res. Report W 57.

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Abstracts

Below are two abstracts that were presented at the Geological Society of America's Northeastern Section meeting in March, 2006. These two abstracts outline the results of the survey.

Availability and Field Water-Quality of Ground Water in the Marburg Schist in West Manheim Township, York County, Pennsylvania – Low, Dennis J., U.S. Geological Survey, Low; Kathryn K., Susquenita High School; Jones, Jeri L., Jones Geological Services; Peacock, Gary, York County Conservation District.

Current population growth of about 5 percent per year in West Manheim Township (Township) coupled with recent droughts has led Township officials to undertake an effort to evaluate the capability of the bedrock aquifers to meet future, water-resources needs. Availability of ground water in the Township is limited by the physical characteristics of the underlying bedrock and its upland topographic setting. The Marburg Schist, which underlies approximately 90 percent of the Township, is one of the lowest yielding aquifers in the Commonwealth. About 25 percent of the wells in the Marburg Schist have driller reported yields of 2 gallons per minute (gal/min) or less, and 50 percent of the wells have specific capacities of 0.09 (gal/min) per foot of drawdown or less, indicating borehole storage contributes significantly to driller reported yields. Driller reports also indicate water-producing zones are shallow and few in number. In general, 50 percent of the water-producing zones are penetrated by a depth of 87 ft and 90 percent by a depth of 183 ft. Nonparametric tests (Spearman) indicate strong inverse correlation between well depth and yield (-0.71) and well depth and specific capacity (-0.66). Field measurements of pH and specific conductance indicate that water in the Marburg Schist is slightly acidic and relatively low in dissolved solids. Approximately 50 percent of the wells sampled contained water with a pH less than the U.S. EPA secondary drinking water regulation of 6.50. Specific conductance ranged from 80 to 1,720 microsiemens per centimeter (uS/cm), the median was 187 uS/cm.

PROBLEMS ENCOUNTERED AND RECOMMENDATIONS MADE DURING A GROUND-WATER SURVEY WITHIN THE MARBURG SCHIST IN WEST MANHEIM TOWNSHIP, YORK COUNTY, PENNSYLVANIA.  JONES, Jeri L., Jones Geological Services, 276 North Main Street, Spring Grove, PA  17362, JLJ276@aol.com, LOW, Dennis J., U. S. Geological Survey, 215 Limekiln Road, New Cumberland, PA 17070, djlow@usgs.gov, LOW, Kathryn K., Susquenita High School, and Peacock, Gary R., York County Conservation District

West Manheim Township (Township) is in southwestern York County, Pa., and is within the Piedmont Physiographic Province, Piedmont Uplands Section, where it is underlain predominantly (90 percent) by the Marburg Schist.  Because of its proximity to major metropolitan centers, the Township faces rapid development and growth - an estimated 4,000 new homes are projected in the next 5 years.  With only 30 percent of households using public supplies, much of the water needs must be met through private domestic wells.  The availability of ground water in the Township, however, is uncertain.  Homeowners commonly have described the need for drilling two, three, and in some cases, six wells before a suitable yield was established.  To better evaluate the potential of the Marburg Schist to met projected water demands, the Township initiated a ground-water study in February 2005.  As an initial step in the study, 422 well-driller cards and/or consultant reports from local, state, and Federal databases were examined.  A total of 164 wells (39 percent) were determined to have satisfactory spatial coordinates of 0.1 to 2 seconds latitude and longitude (based on site visits, street addresses, parcel or lot numbers, and/or driller maps) to accurately plot the wells on existing digital (topography, geology) coverages. The remaining 258 wells could only be roughly located (3 to +30 seconds latitude and longitude or 200 to +3,000 feet) but were nevertheless assigned to the Marburg Schist because of the predominance of this aquifer in the Township. Although all 422 wells were used to evaluate the Marburg Schist, significant hydrogeologic information (for example: effects of topographic setting, lineaments, and lithology on yields; distribution of well yields; and depth to bedrock) could not be obtained from 60 percent of the examined databases. This lack of adequate data coverage thus prevented an adequate assessment of spatial variation or trends in well yield and specific capacity. As a result, several recommendations were presented to the Township to improve their collection of well data including (1) purchase and utilize a Global Positioning System to obtain proper spatial coordinate data for each well, (2) visit sites to obtain static water levels after well completion, (3) perform minimum 1-hour drawdown tests with measurement of discharge volume, and (4) develop an electronic database for well-driller records.

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What is SWL?  It stands for Static Water Level or in more understandable terms, the depth below the surface where water is first recorded.  

Wells Surveyed with Static Water Level Depth Range

Wells within the Marburg Schist Listed Chronologically

Wells within the Marburg Quartzite Listed Chronologically

Wells within the Marburg Slate Listed Chronologically

Wells within the Harpers Formation Listed Chronologically

Comparison for SWL between 2005 Survey and Driller’s Cards

MAPS

(click on maps to enlarge)

      #1                                   #2                           #3                         #4                            #5                            #6

#1 - Location of West Manheim Township in York County, PA

#2 - Geologic Map showing well locations

#3 - Poteniometric Map

#4 - Depth to water chart for all wells surveyed

#5 - Well yields of all wells surveyed

#6 - Depth to bedrock all of wells surveyed

        #7                              #8                           #9                             #10                         #11                           #12

#7 - pH of wells tested

#8 - Specific conductance

#9 - Maximum depth of water-bearing zones vs. # of wells

#10 - Yield vs. maximum depth of water-bearing zones

#11 - Well depth vs. yield

#12 - Well depth vs. # of wells