Delaware is not in a seismically active region but, even here, earthquakes occur because of sudden adjustments in the earth's crust. Even though such movements can be startling they yield important information about the behavior of the earth and the potential for future events. The Delaware Geological Survey continually monitors seismicity in the State because of both the scientific value of the information and to help address the concern of residents and other agencies over possible effects.
The Delaware Geological Survey Cartographic Information Center has made the DGS a focal point for questions concerning the availability of all types of aerial photography, thematic maps, planimetric maps, topographic maps, historic maps, LANDSAT imagery, space imagery, side looking aerial radar imagery (SLAR), and geodetic control. Sources of maps, charts, aerial photography, boundary mark information, and vertical geodetic control can be obtained for your area of interest within the State through the Center's computer-searchable data bases.
The Delaware Geological Survey has unveiled a new version of their public web site. Although many of the technologies employed are consistent with modern web standards, giving the user a familiar feel and comfort level, particular attention has been paid to information and the retrieval of it. The site is designed to encourage users to explore content they wouldn't other wise read.
The DGS, in response to the needs for efficient storage, manipulation,retrieval, and report-generating capability, has proceeded with the conversion of the paper file data base to an integrated automated geologic, hydrologic, and mineral resource management information system. It is necessary to organize data in a systematic and standardized fashion for efficient entry into the automated system. To accomplish this, the DGS has made major revisions in the data recording and filing systems.
The Delaware Geological Survey (DGS) has published the surficial geology of the state of Delaware at a scale of 1:100,000 for New Castle and Kent counties (Ramsey, 2005, 2007). Maps at this scale are useful for viewing general geologic framework on a county-wide basis, determining the geology of watersheds, and recognizing the relationship of geology to county-wide environmental or land-use issues. These maps, when combined with subsurface geologic information, provide a basis for locating water supplies, mapping ground-water recharge areas, and protecting ground and surface water. Geologic maps are also used to identify geologic hazards, such as flood-prone areas, to identify sand and gravel resources, and for supporting state, county, and local land-use planning decisions. Portions of Sussex County have previously been mapped at 1:24,000-scale.
This project is designed to deliver, by web-based technologies, the most commonly available and requested geologic and hydrologic information used in hydrologic studies required by regulation and ordinance and used by state agencies to support resource-management decisions. Available information can be associated with points or areas. Information associated with points includes descriptive logs, geophysical logs, raw and interpreted groundwater levels, aquifer and geologic unit identification, and hydraulic characteristics of wells. Information associated with areas is either in the form of raster-based (grid) data or polygons. Examples of raster-based data include water-table depths and elevations, tops and thicknesses of geologic and aquifer units, and aquifer transmissivity. Examples of polygons include surficial geology and groundwater recharge potential.
The intent of developing a web-technology enabled system is to provide a more intuitive and comprehensive toolset for locating, quickly viewing, and downloading the desired information in an efficient, extensible, and familiar manner.
Map showing the types of Earth science maps that are available from State, Federal, and County agencies. Final revision was March of 1990. This publication is now Out-Of-Print.
Scott Andres and Edward Walther, of the Delaware Geological Survey, presented "Development and Application of a GIS Screening Tool for Assessing Suitability of Land for Rapid Infiltration Basin Systems" at the National Ground Water Association Summit, Denver, April 12-15. Andres also participated in a panel discussion co-sponsored by the U.S. Subcommittee on Groundwater, "National Groundwater Monitoring Network: Listening Session."