Reports
Deep Creek Lake sediment accumulation study: a map reconnaissance of selected coves
2011, Ortt, R.A., Jr., and Manship, V.
File Reports, Coastal and Estuarine Geology, File Report 2011-06
Executive Summary
Ten coves were studied in Deep Creek Lake for sedimentation which may have occurred since 1970. These coves were from different geographical parts of the lake, and they were selected based on varying land uses, watershed types, geology, terrain, and the DNR Park Manager input.
Current depths of the lake surveyed between 2007 and 2011 were compared to a historical DNR bathymetry map from the early 1970s. The difference between the current depths and the historical depths capture the sedimentation which occurred over the last forty years.
Of the ten studied sites, two sites demonstrated that they are erosional, four sites demonstrated no changes, and four sites demonstrated sediment deposition.
Where sedimentation is occurring, it is following a very standard deltaic deposition process where the headwaters of the coves have an increased sedimentation rate while the more distant portions of the lake from the stream inputs show little sedimentation. The data in this study shows that where sedimentation is occurring, it is occurring between zero and nine hundred feet from the cove headwaters (stream inputs). Beyond nine hundred feet from the headwaters, sediment accumulation is confined to isolated areas in water depths greater than 20 feet.
A majority of the observed sediment accumulation is between 0.5 and 2.5 feet over this forty year period. Of the 108 observations, there were three observations of 3 foot sediment accumulations amounts.
In over eighty-seven percent of the observed sedimentation locations, less than ten percent of the navigable water depth was impaired. Isolated locations showed a maximum of thirty-eight percent impairment from the 1970s depth (ex. 3 feet of sediment has accumulated where in 1970 there was 8 feet of water depth).
Additional studies to quantify the sedimentation throughout the lake, and the sources of sedimentation are recommended.
