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This work is part of a larger effort to provide estimates of water-table elevations and depths to water for the Coastal Plain portion of Delaware. These maps will be used in risk assessments and for environmental management decision-making. |
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This work is part of a larger effort to provide estimates of water-table elevations and depths to water for the Coastal Plain portion of Delaware. These maps will be used in risk assessments and for environmental management decision-making. |
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Matthew J. Martin and A. Scott Andres |
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<DIV STYLE="text-align:Left;"><DIV><DIV><P><SPAN>This digital product contains gridded estimates of depth to water (dtw) under wet conditions for Delaware. This work is the final component of a larger effort to provide estimates of water-table elevations and depths to water for the Coastal Plain portion of Delaware. Mapping was supported by the Delaware Department of Natural Resources and Environmental Control and the Delaware Geological Survey. These grids were produced with the same multiple linear regression (MLR) method as Andres and Martin (2005). Briefly, this method consists of: identifying dry, normal, and wet periods from long-term observation well data (Nc45-01, Ng11-01, Qe44-01); estimating a minimum water table (Sepulveda, 2002) by fitting a localized polynomial surface to elevations of surface water features (e.g., streams, swamps, and marshes); and computing a second variable in the regression from water levels observed in wells. A separate MLR equation was determined for dry, normal, and wet periods, and these equations were used in ArcMap v.9 (ESRI, 2004) to estimate grids of water-table elevations and depths to water. The grids have 30-m horizontal and 1-ft vertical resolutions. Grid world files and ground-water level observation data are in UTM-18N, 1983 projection in meters and elevations are in feet, NAVD 1988. Files are in ESRI, Inc., grid format. These data were combined from DGS Digital Data Products DP05-01, DP05-03, and DP05-04 Digital Water-Table Data for Sussex, Kent, and New Castle counties, Delaware, respectively. REFERENCES CITED Andres, A. S., and Martin, M. J., 2005, Estimation of the water-table surface for the Inland Bays watershed, Delaware: Delaware Geological Survey Report of Investigations No. 68, 20p. ESRI, 2004, ArcMap v. 9, Redlands, California. Sepulveda, N., 2003, A statistical estimator of the spatial distribution of the water-table altitude: Ground Water, vol. 41, p. 66-71.</SPAN></P></DIV></DIV></DIV> |
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<DIV STYLE="text-align:Left;"><DIV><DIV><P><SPAN>The Delaware Geological Survey (DGS) is constantly gathering data from multiple sources, interpreting data, and reflecting its interpretations in a variety of data formats. DGS's interpretations are conceptualized in these grids of Depth to Water for Delaware. The water table is a continuous surface; however, observations of the surface exist at irregularly spaced locations. In this instance, regularly spaced grids of water-table elevations were estimated from site-specific observational data and are the model used to represent the water-table surface. Reasonable efforts have been made by the DGS to verify that the digital data provided herein accurately interpret the source data used in its preparation. These are estimated surfaces and they may be inappropriate for some applications. Detailed site-specific investigation may be required for evaluating individual sites. Persons wishing to apply the data in these grids to more detailed scales are encouraged to contact the DGS office for advisement. Nothing contained herein shall be deemed an expressed or implied waiver of the sovereign immunity of the University of Delaware and the State of Delaware or their duly authorized representatives, agents, or employees. Additional Information In order to provide complete data coverage for the entire Coastal Plain, Sussex County, Kent County, and New Castle County grids (Digital Products DP05-01, DP05-03, and Dp05-04) were merged together. Further manipulation of these data grids by the user is done solely at the descretion of the user.</SPAN></P></DIV></DIV></DIV> |
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Depth to Water (wet conditions) |
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["New Castle","Milton","South Bethany","Blades","Felton","groundwater","Arden","Kent County","Kenton","Wyoming","Ardencroft","Bethel","Bethany Beach","Greenwood","Dagsboro","Seaford","Little Creek","Frankford","Millsboro","Ellendale","Millville","Hartly","Water Table","inlandWaters","Elsmere","Camden","Lewes","Farmington","Townsend","Woodside","Henlopen Acres","Wilmington","Harrington","Viola","Leipsic","Selbyville","Smyrna","Delaware Hydrology","Houston","Bridgeville","Rehoboth Beach","Ocean View","Newark","Middletown","Fenwick Island","Milford","Georgetown","New Castle County","Delmar","Frederica","Magnolia","Laurel","Claymont","Newport","Bellefonte","Odessa","Delaware","Clayton","Sussex County","Dover","Slaughter Beach"] |
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en-US |
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150000000 |
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