The Naval Facilities Engineering Command (NAVFAC) Washington requested a hydrogeological investigation be completed to assess the impact of the proposed construction of a 58,800 SF 3-story underground parking garage on the nearby Lake Eleanor at the Walter Reed National Military Medical Center (WRNMMC). GeoConcepts conducted a thorough review of historical topographic maps, geological data, and hydrological data to gain an understanding of nearby hydrogeological trends and conditions. GeoConcepts utilized field investigation data compiled by others from a previous geotechnical study, including additional groundwater monitoring wells, to conduct in situ aquifer testing, estimate groundwater flow direction, and analysis recharge of the lake.
They were able to determine the transmissivity and hydraulic conductivity of the shallow aquifer based on pump tests and slug tests performed at the wells. Based on GeoConcepts’ assessment of the data the planned dewatering well and pumping test were deemed unnecessary, saving NAVFAC over $40,000 in drilling and engineering labor expense.
A final report was provided to the client summarizing the results of the hydrogeological study and the implications for any potential impact of the proposed parking garage structure to the hydrology of Lake Eleanor and its environs. Based on the findings of the field investigation, review of readily available literature, and knowledge of the regional hydrogeology, it was concluded that it would be highly unlikely for the parking deck to have a negative effect on Lake Eleanor or its source spring in terms of water volume.