Fairfax County, Virginia
Owner: Northern Virginia Stream Restoration, L.C.

WSSI performed a bathymetric survey of Lake Audubon in Reston, VA, in advance of stream restoration taking place upstream in the watershed.  The survey documented the pre-construction bathymetry and will be followed by a post-construction survey to quantify the volume of sediment deposited in the 46 acre impoundment from the stream restoration activity.

WSSI performed the survey in accordance with the U.S. Army Corps of Engineers Engineering and Design Hydrographic Surveying Manual No. EM-1110-2-1003, Chapters 5, 8, and 9 (dated April 1, 2004).  The survey was oriented horizontally to the Virginia Coordinate System of 1983, North Zone, and the Vertical Datum is referenced to the National Geodetic Vertical Datum of 1929, in accordance with both the COE manual and Fairfax County policy.  WSSI established horizontal and vertical datums using real time DGPS.

To determine depth measurements and elevations, WSSI used Single Beam Echo Sounding Equipment (ODOM ECHOTRAC CVM) in the deeper portions of the lake and a sounding pole in the shallow areas.  WSSI then created a digital terrain model (TIN) and contours based on the survey data points collected.  Upon the conclusion of stream restoration activities, WSSI will compare the pre-construction TIN to the post-construction TIN (which will be developed in the same manner) and will calculate the volume of material deposited during the restoration project.