Tuesday, April 1, 2008 : 10:40 a.m.

Conducting a Preliminary Water Supply Feasibility Assessment with Limited Data in Southern California

Ethan O. Weikel, PG and Brian P. Shedd, Kleinfelder Inc.

A preliminary investigation including a water balance and feasibility assessment was undertaken for a site in southern California to determine an estimate for the quantity of potentially accessible groundwater.  Limited site-specific data was available, yet information and an assessment were needed in order to guide the overall project direction.

In conducting this investigation, historic reports and other available data from the local area were acquired and assessed; including precipitation, evapotranspiration, geology, and land cover.  A water balance was created using the Thornthwaite methodology in order to evaluate the water available for infiltration per unit area of delineated watershed.  Two scenarios were assessed, the first limited to watershed area within the site area, and the second evaluated watershed area where infiltrated water may be accessible from on site pumping.  Values for precipitation available for infiltration, based on regulatory guidance, were also considered.

Analysis of the water balance results revealed that the calculation is extremely sensitive to the parameters pertaining to the availability of water for deep infiltration, indicating that site specific investigation is needed to add confidence to these parameters.  Using the water balance results, and simplified aquifer geometry, an average perennial yield and first-order approximation of water level change over time were generated.

Ethan O. Weikel, PG, Kleinfelder Inc. Mr. Weikel received a B.S. in Structural Geology from the College of William and Mary in Virginia. At William and Mary, his focus was also on sedimentology and stratigraphy, and included field mapping for the U.S. Geological Survey in the Virginia Piedmont Province. Mr. Weikel continued his work in northern California with an emphasis on hydrogeology and water resources. Mr. Weikel is a Professional Geologist with licensure in CA, DE, PA, and VA and is currently working in the Mid-Atlantic as a Project Manager and Hydrogeologist, focusing on hydrogeologic assessment and water resources management.

Brian P. Shedd, Kleinfelder Inc. Mr. Shedd received a B.S. degree in geology with a focus in water resources from the State University of New York College at Oneonta. Mr. Shedd is currently employed by Kleinfelder, working as a hydrogeologist on complex, small-scale, hydrogeologic investigations and contaminant assessment and remediation in Maryland, Virginia, Delaware, and Washington DC.


2008 Ground Water Summit