Delaware Maps

Digital Data Availability Summary

Click for local parcel information. Map courtesy Digital Map Store

Why is marine cadastral data important for conservation and marine spatial planning?

Marine Cadastral Data Management

The Delaware Coastal Programs office participated in TNC’s Nationwide Comparative Assessment of State-level Marine Cadastral Data, including an interview on Delaware’s marine data needs and marine cadastral data management,1 and a written inventory (pdf) of Delaware’s state-level marine cadastral data (SMCD).2

State Data Management: Delaware has been a leader in the development of NSDI Framework data. Tthe Delaware DataMIL provides statewide access to state Framework layers from multiple departments. The Delaware Environmental Navigator and ArcIMS applications give access to statewide data sets from the Department of Natural Resources and Environmental Conservation. In addition, the state is currently (as of 2011) developing a statewide in-house data portal to allow agencies to access each other’s data directly. The Delaware Geographic Data Committee was awarded a CAP grant from the Federal Geographic Data Committee (FGDC) to write a strategic plan and related business plans for state spatial data infrastructure. The strategic plan calls for the establishment of a state geographic data office with a state geographic data coordinator.3

Marine cadastral data is not currently being considered within the strategic plan. Delaware Coastal Program's staff suggests that the need for detailed marine cadastral data may be mitigated by the Delaware Coastal Zone Act, which categorically excludes heavy industry from the coastal strip and subaqueous lands. Since, along the Delaware River before it opens into Delaware Bay, Delaware owns the entire bottom up to mean low water on the New Jersey side, Delaware also has a strong influence over coastal development in part of New Jersey.

A central concern for Delaware is resolution of the state marine boundary with New Jersey seaward of the mouth of Delaware Bay. Does the boundary run perpendicular to the midpoint of the bay closing line (roughly southeast) or due east? A due east line gives Delaware a larger territorial sea, but the greatest difference between the two lines is beyond the 3-nautical-mile Submerged Lands Act Boundary, where it impacts federal consistency review and federal-state revenue sharing. In 2009, Delaware initiated discussion of their concern with the U.S. Minerals Management Service, which has drawn its administrative boundary following a line perpendicular to the bay closing line. Delaware is also negotiating with the neighboring states of Maryland, New Jersey and Virginia on areas subject to interstate consistency review.

Marine Cadastre and Supporting Data

Cadastral Reference System: Delaware does not currently manage its marine cadastral data as a unified system, but has produced for TNC a first-cut inventory of state-level marine cadastral entities, data, and authoritative sources. Like most states, Delaware does not use a marine cadastral reference grid. Consistency in coastal and marine mapping has been helped by development of a common base map, including coastline, based on 2002-2005 aerial imagery.

Shorelines and Bathymetry: Shorelines are available from the DataMIL as part of the state boundary. Bathymetry is currently being developed as part of the Delaware Bay Benthic Mapping program, although coverage will not include all of Delaware waters or shallow nearshore areas. As reviewed above, the marine boundary with New Jersey lacks agreed legal clarity.

Coastal Imagery: Coastal imagery was acquired statewide in 2007 at .25-meter resolution. It can be viewed and downloaded on the DataMIL. Historic aerial imagery is also available for download (2003, 1992, 1968, 1954 and 1937).

Marine Jurisdictional Boundaries and Submerged Lands: Counties are currently working on common GIS boundaries. Not all portions of state-owned submerged lands have available digital boundaries.

Ownership, Leases and Other Authorizations: Upland ownership generally extends to mean low water, except in one area along “The Strand” in New Castle, where a small number of properties with title deriving from King’s Grants extend beyond mean low water into the Delaware River. Leases are required, but are not tracked spatially, for structures, aquaculture, dredge disposal and other activities affecting submerged lands.

Marine Managed Areas : Spatial data exist on a number of marine managed areas in Delaware waters, including artificial reefs and the Delaware National Estuarine Research Reserve, but they have not been gathered into a repository for inventory or central access. A detailed discussion is provided below in the Marine Managed Areas section.

Local Parcel Information: Local government parcel data is available for download from the DataMIL and the Delaware Environmental Navigator.

GIS Portals

• Delaware Data Mapping and Integration Laboratory (DataMIL) (web site). Metadata, downloads and web mapping services for all Delaware Spatial Data Framework layers. Contents are briefly described at the Geospatial Data Resources web page of the Office of State Planning Coordination, University of Delaware RDMS Map Server (web site)
• Delaware Environmental Navigator (web site). Search Department of Natural Resources and Environmental Control information by permitted facility, program, inspection, violation, enforcement action, permit, or release, or use online interactive map. The online interactive map includes many of the DSDF layers in the Delaware DataMIL.
• Delaware Spatial Data Catalog (web site). Provides text search of Geospatial OneStop (GOS) for Delaware and a catalog organized by category, with links to data, for “some of the key geospatial data resources for the state of Delware.”

Reference and Supporting Data

Cadastral Reference Grid

Shorelines

Coastal Imagery

Bathymetry

Marine Jurisdictional Boundaries

Submerged Lands Boundaries

No data found.

Ownership

Submerged Lands Parcels

General Property and Parcel Data

Public and Conservation Lands

Leases and Other Use Authorizations

The Wetlands and Subaqueous Lands Section of Delaware DNREC authorizes structures and activities in tidelands and submerged lands, but does not maintain digital spatial data on such authorizations.

Aquaculture and Shellfish

Other Use Authorizations

Marine Managed Areas

Delaware’s SMCD Inventory for TNC (pdf) indicates that spatial data exists for the following marine managed areas. Although this data have not been gathered in a central repository, they may be available from the responsible agency.

The National Marine Protected Areas Center’s MPA Inventory (web page) includes the following marine areas managed for conservation within Delaware state waters:

The National Marine Protected Areas Center also maintains a De Facto MPA Inventory for marine areas managed for purposes other than conservation. It includes 21 marine areas managed by federal authorities within Delaware state waters. The US Coast Guard manages anchorage areas and the Delaware Bay Regulated Navigation Area (which includes all of Delaware Bay). There is at least one restricted areas and one danger zone managed by the US Navy or other agencies. A report summarizes the De Facto MPA inventory, and a downloadable shapefile for the inventory may soon be available. (web page)

Local Parcel Information

Kent County (web page)

New Castle County (web page)

Sussex County (web page)

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