Updating Shoreline Rates of Change in Maryland
Since the early 1900s, the Maryland Geological Survey (MGS) has monitored, mapped, and quantified shoreline change along tidal bodies of water in the State – namely, the Chesapeake Bay and its major tributaries, the Atlantic Ocean, and the coastal bays separating the Atlantic coast barrier islands from the mainland.
During the 1990s and early 2000s, MGS, in partnership with Maryland’s Coastal Management Program (CMP) completed the following tasks:
- digitized a series of mapped historical shorelines;
- oversaw the interpretation of a ca. 1990 shoreline from digital orthophotography;
- published a series of more than 100 quadrangle-based Shoreline Changes maps;
- determined shoreline rates of change; and
- classified reaches of the ca. 1990 shoreline according to generalized erosion rates (e.g., no, slight, low, moderate, and high rates of erosion)
With assistance from MGS, Maryland’s CMP subsequently created a website, Maryland’s Coastal Atlas – Shorelines, that displays the results of this work, and collaborated with its Coastal Restoration Specialist and Shoreline Conservation and Management group to incorporate this work into planning, evaluation and decision-making regarding the State’s shorelines.
Historical shoreline files (.dxf, .shp, and .e00 format) and the Shoreline Changes maps (PDF format) are available online via the MGS website here under “Shorelines”: http://www.mgs.md.gov/coastal_geology/past_projects.html
Maryland’s Coastal Atlas website may be accessed here: http://gisapps.dnr.state.md.us/coastalatlas/WAB/index.html
It has been nearly two decades since the last revision and the shoreline change data is beginning to be less useful in shoreline management. Since the last recorded shoreline change rate was calculated (1990), Maryland has experienced several large storms (Isabel, Sandy) that have likely changed the shorelines in a number of coastal counties.
To address this need for current data, MGS is updating shoreline change information for several tidewater counties in Maryland. Shoreline change updates in Anne Arundel County, Baltimore County (including the Baltimore City limits), Calvert County, and Prince George’s County are complete. Updates in Harford County are currently underway with an expected completion date of October 2016.
Building on previous work, MGS is assembling newly digitized historical shorelines, acquiring recent (post-2000) shorelines, running the latest version of DSAS (Digital Shoreline Analysis System - Digital Shoreline Analysis System - http://woodshole.er.usgs.gov/project-pages/DSAS/), and assigning generalized erosion rate categories to recent shorelines in each county.
MGS is working cooperatively with Maryland’s CMP to upload the results of these activities to Maryland’s Coastal Atlas, disseminate and communicate the information to key stakeholders, and incorporate the work into shoreline management.
These county-wide projects will hopefully build upon each other, with the ultimate goal being a complete shoreline change update for all sixteen of Maryland’s tidewater counties.
Funding for these projects has been provided by grants from the National Oceanic and Atmospheric Administration (Award Nos. NA13NOS4190143 and NA13NOS4190136), administered by the Maryland Department of Natural Resources, Chesapeake and Coastal Service.