Summer 2007 New Geologic Map of Kent County by K

RESEARCH DELAWARE

First State Geology SERVICEGEOLOGICAL Current information about Delaware‘s geology, hydrology, and mineral resources SURVEY Published twice yearly by the Delaware Geological Survey EXPLORATION University of Delaware

Vol. 25, No. 2 • Summer 2007 New Geologic Map of Kent County By K. W. Ramsey This summer, the Delaware Geological Survey will release a new geologic map, “Geologic Map of Kent County Delaware” (Geologic Map Series No. 14), which presents the results of research by Kelvin W. Ramsey. This map is the second in a series of three 1:100,000-scale county-wide geologic maps showing the formations found at the land surface. The New Castle County map (Geologic Map Series No. 13) was released in 2006. The purpose of these maps is to provide geologic information on a county-wide scale that can be used for determining the geology of watersheds, recognizing the relationship between geology and regional environmental or land-use issues, identifying potential locations of sand and gravel resources, and providing geologic data for local land-use and regulatory planning decisions. When used in conjunction with subsurface geologic information, these maps aid in locating water supplies for public, domestic, agriculture, and industrial use, mapping ground-water recharge areas, and protecting ground- and surface- water resources. The geologic map of Kent County was constructed using data collected from drilling and coring the subsurface, exam- ining outcrops, and collecting shallow hand-auger borings. Additional data were collected from drillers’ logs, geophysical logs, and samples located in the DGS data repositories. Aerial photographs and soil maps were also used throughout the investigation. Using stratigraphic units previously published on the geologic map of New Castle County and on DGS Geologic Map Series No. 8 (Milford and actually extends over much of central and tion, and industrial water supplies. Mispillion River quadrangles), surficial western Kent County into areas previous- Descriptions and ages of all the units geologic units were extended south and ly mapped as the Columbia Formation. shown on the map and cross sections are southeastward into Kent County. Accompanying cross sections show the included as well. Ongoing work in the southern portion of stratigraphic units that lie beneath the sur- The geologic map of Kent County doc- the state suggests that the Beaverdam ficial units depicted on the map. Many of uments a combination of several ongoing Formation, previously considered to be these subsurface units function as aquifers projects of the DGS to understand and restricted to portions of Sussex County, and are used for public, domestic, irriga- map the geology of Delaware and was in part funded by a STATEMAP grant from nies regularly the Association of American State install wells, col- Geologists and the U.S. Geological lect well water Survey. samples, and Geologic Map Series No. 14 will be measure water available to view online or as a down- levels from wells loadable product from the DGS Web page throughout at www.udel.edu/dgs/publ.htm. Printed Delaware. copies of the publication may be request- In recognition ed by contacting the DGS at (302) 831- of the fact that 2833 or via e-mail at water levels are [email protected]. one of the most basic and impor- Delaware Geological tant measurements Survey’s Statewide made in the study Data collection also involves gleaning of ground water, the Delaware Geological previously reported data from publica- Ground-Water Monitoring Survey has had a water-level monitoring tions and archived records. Water-levels Network network in continuous operation since the from historical well completion reports mid-1950s. The goals of the monitoring By A. S. Andres and driller’s notes are valuable pieces of network are to (1) systematically collect Ground water is one of Delaware’s information that are added to the Oracle ground-water level data; (2) analyze most important natural resources and is database. In addition, the DGS routinely trends; and (3) report our findings. the source of all retrieves, reviews, and catalogues water- Through half a century of conducting potable water for level data collected by the Department of basic research on Delaware aquifers and areas south of Natural Resources and Environmental ground water and working with water New Castle the Chesapeake Control (DNREC) and the Delaware suppliers, water managers, researchers, County and Delaware Department of Agriculture. and the public, the DGS has developed Canal. Proper use, Water samples from selected major sup- and maintained a comprehensive network allocation, manage- ply wells located along the Atlantic Coast of monitoring wells in which we collect ment, and protection of in eastern Sussex County are collected water-level measurements and water sam- our ground water and analyzed annually for chloride con- ples. require adequate infor- centrations. A key concern in this area is mation about the the potential for degradation of water aquifers that supply Data Collection quality caused by overuse of ground our water and the The DGS regularly monitors water lev- water and subsequent intrusion of salt physical and chem- els in more than 70 wells, which are water. To keep apprised of conditions in ical characteris- screened in 11 aquifers and distributed this area, ground-water levels are meas- tics of the water. throughout New Castle, Kent, and Sussex ured at high temporal and spatial frequen- To obtain this counties. Manual measurements are cies in the vicinities of several major information, taken monthly and quarterly using either water supply wells. This data collection electric tape or an electric sounder (M- effort is a part of Delaware’s Coastal Kent County the Delaware scope). Automated measurements are Aquifer Monitoring Program, conducted Geological recorded every 15 to 30 minutes by pres- in cooperation with DNREC. Survey and sure transducer-datalogger systems in 15 other gov- of the wells. Data are retrieved quarterly from these instruments and downloaded Distribution of Ground-Water Data ernmental These measurements have a wide vari- to an Oracle database. Because of agencies ety of applications. For instance, the improvements in the temporal resolution and private depth to the water table is a limiting fac- of the data and the time savings achieved compa- tor in constructing buildings and roads, collecting the data, we plan to increase designing and locating land-based waste- the number of automated systems by three water disposal systems, and for irrigating per year. crops. Ground-water elevations are used Water-Level Monitoring to calculate ground-water flow directions Continuous and rates and to support more comprehen- Monthly sive interpretations of availability and Sussex County Quarterly sustainability of water supplies, rates and directions of contaminant transport, water Chloride Monitoring Annually use and disposal permits, and to project future ground-water conditions. Total Number of Wells* The DGS received over 100 requests New Castle 23 from state agencies, consultants, and the Kent 8 pubic for ground-water data in the past Sussex 43 year, and the number of requests per year 020 Kilometers has steadily grown. This number does not * All wells are not represented include ground-water data directly on the figure due to the scale of the image. retrieved from the DGS website. Drought

2 • First State Geology Summer 2007 or flood conditions increase the number for wells with 20 or more years of (SOGW), a part of the National Advisory of these requests. In addition to respond- record. Committee on Water Information. Scott ing to direct requests, we also distribute The tables are formatted for perform- will be representing the 50 states as co- information through the monthly series ing statistical analysis and for producing chair of the Data Standards and Data Summary of Water Conditions in charts and are accessible at Management workgroup of SOGW. Delaware and through presentations at http://www.udel.edu/dgs/Hydrology/his Participation on this subcommittee will meetings of Delaware’s Water Supply torical/wl_stats2.html. keep Delaware current with national pro- Coordinating Council and the Governor’s (4) Digital water-table data for New grams that measure, manage, and distrib- Drought Advisory Committee. Castle, Kent, and Sussex counties, and ute ground-water information. While reviewing the types of data the thickness, elevation of the base, and requested over the years the DGS identi- transmissivity of the unconfined aquifer fied several commonly recurring ques- in eastern Sussex county. These digital Publications tions and developed several publications products (DP05-04, DP05-03, DP05-01, and Internet-based self-service basic data and DP06-01, respectively) are available Recent DGS Publications and interpretive products. These include: as GIS-ready map layers and can be Geologic Map Series (1) A table listing wells having 100 or accessed at http://www.udel.edu/dgs/ No. 14, Geology of Kent County, more water-level observations or wells Publications/pubform.html. Delaware: Kelvin W. Ramsey, scale having 20 more years of record and more Recent surveys of our stakeholders 1:100,000. than 75 water-level measurements. have revealed that most data users want Additional information provided includes to have more information available the northing, easting, and altitude of each through Internet-based self service means Open File Reports well, the aquifer screened, and the date and many users want some sort of map No. 46, Storm-water and Baseflow the well was drilled. Data accessible on interface to access the data and additional Sampling in the Nanticoke River this webpage (http://www.udel.edu/dgs/ tools to display the data. As a result, the Watershed: Preliminary Report of Hydrology/histgw.html) are a subset of DGS is developing the map interface for Findings 2002-2004: A. Scott Andres, DGS holdings and are updated quarterly. data retrieval and new tools to improve William J. Ullman, and Karen B Savidge, A data link for the well of interest pro- data display capabilities. 20 p. vides access to a comma delimited text DGS staff members also have begun No. 47, Digital Watershed and Bay file of all available water-level data for developing additional capabilities to link Boundaries for Rehoboth Bay, Indian that well. Hydrographs are available as our monitoring well network to other cli- River Bay, and Indian River, Thomas E. PDF files for a subset of wells that have mate and environmental data distribution water-level recorders. sites, most notably DEOS, the Delaware McKenna, A. Scott Andres, and (2) A table listing wells with 4 or more Environmental Observation System Kerrilynn P. Lepp, 8 p. water-level measurements, which are (http://www.deos.udel.edu/). To date, accessible at http://www.udel.edu/dgs/ two DEOS stations have been equipped Staff Notes Hydrology/historical/wl_rpt3.csv. with monitoring wells. The water-level Additional information provided includes data from those wells will soon be avail- Presentations the northing, easting, and altitude of each able through DEOS. Members of the Delaware Geological well, the top and bottom of the screened We also work with our federal counter- Survey were invited speakers at the 2007 interval, the number of observations, the parts, the U.S. Geological Survey, and Delaware Water Science Seminar, April 25, aquifer screened, and the period of other state agencies, including DNREC in Dover: A. Scott Andres, “3D Geologic record. Also included are the minimum, and the Department of Agriculture to average, and maximum water levels. coordinate the work of our respective Mapping at the DGS;” Thomas E. This list is formatted for easy import to agencies. Recently, DGS Senior McKenna, “Remote Sensing of geographic information systems (GIS). Scientist, A. Scott Andres, was nominat- Temperature to Characterize Ground- (3) A file containing tabulations of ed by the National Ground Water Water/Surface-Water Interaction in monthly minimums, quartiles, averages, Association and appointed a member of Delaware;” and Peter P. McLaughlin, Jr., maximums, and period of record values the Subcommittee on Ground Water “Geology of the Confined Aquifers of

First State Geology Summer 2007 • 3 Kent County: Stratigraphy, Mapping, and Delaware GIS 2007 conference, Dover, Army Corps of Engineers, Philadelphia Hydrogeological Implications” and May 2; “Geocollaboration: Collaborative District, for their work on a multi-year “Geology of the Potomac Aquifer of Methods for Working with Geospatial ground-water modeling study that provid- Northern New Castle County: Keys to Data,” TUgis conference. ed a more comprehensive understanding Improving Hydrogeological of the Potomac aquifer system. Characterization.” Service and Awards Miriam L. Pomilio presented A. Scott Andres, “Results of the A. Scott Andres was nominated by the “Geographic Information Systems, Domestic Well Water-Quality Survey,” National Ground Water Association and Lessons for Educators,” at the Delaware Delaware Cancer Consortium, appointed a member of the Subcommittee Instructional Technology Conference, Wilmington, Feb. 20; and with David on Ground Water (SOGW), a part of the April 18-19. Legates, William S. Schenck, Miriam L. National Advisory Committee on Water Kelvin W. Ramsey participated in a Pomilio, and Bradley L. Strittmatter, Information. Scott will be representing panel discussion on “Sea-Level Rise “Internet-based Hydrologic Data the 50 states as co-chair of the Data Impacts on Ecosystems and Coastal Distribution at the University of Delaware,” Standards and Data Management work- Communities,” Delaware Coastal Issues National Ground Water Association Ground group of SOGW. The National Advisory Workshop, Dover, June 25. Water Summit, April 30. Committee on Water Information repre- William S. Schenck presented a public P. Steven McCreary, “Proper Well sents the interests of water-information lecture on the Geology of White Clay Construction and Management,” Master users and professionals in advising the Creek State Park, March 23; participated Well Owner Network Workshop, Dover, Federal Government on Federal water- as a subject matter expert for the June 2. information programs and their effective- Delaware Board of Professional John H. Talley, “Ground-Water ness in meeting the Nation’s water-infor- Geologists at the National Association of Availability, Trends in Water Demands mation needs. State Boards of Geology Council of Associated with Irrigation and Public Congratulations to Steven V. Bertsche Examiners, Minneapolis, March 29–April Water Supply through 2030, and Potential for 15 years of service at the University 1; presented “Rocks, Minerals, and Conflicts that May Arise from Competing of Delaware. Geologists” to Chester County Cub Scout Demands for Water,” invited speaker at A. Scott Andres, Richard N. Benson, Summer Camp, June 20. Friends of Agriculture Breakfast, Dover, Peter P. McLaughlin, Jr., and Thomas John H. Talley represented Delaware at March 16. E. McKenna were members of the the Outer Continental Shelf Policy Lillian T. Wang, “Surficial Geologic Northern New Castle County Ground- Committee meeting, Annapolis, Feb 20-22. Mapping of Delaware in GIS,” TUgis Water Modeling Team that received the conference, Towson, March 19-20 and at External Partnering Award from the U.S.

RESEARCH DELAWARE Delaware Geological Survey First Class

N University of Delaware Postage S IO E GEOLOGICAL T R V A SURVEY R I C O Newark, DE 19716-7501 E L P A I D P X E Newark, DE 19716 Permit No. 26 First State Geology is published by the Delaware Geological Survey, a State agency established by an Act of the Delaware General Assembly in 1951 and organ- ized as a unit of the University of Delaware. John H. Talley Director and State Geologist Stefanie Baxter Editor, First State Geology CHANGE OF ADDRESS? Send mailing label and your new address, and/or REQUESTS FOR PUBLICATIONS to: Laura K. Wisk Delaware Geological Survey University of Delaware Newark, DE 19716-7501 302-831-2834 [email protected] www.udel.edu/dgs