The more widespread availability of digital floodplain maps (See Field Notes Vol. 18, No. 10) have caused some confusion due to the implied level of accuracy of digital information. There has also been confusion regarding the reconciliation of flood hazard information available from multiple sources and proper use of that data with new topographic surveys for plans of various types. As a result, the Fairfax County Department of Public Works and Environmental Services has prepared guidelines (Guidelines for Delineation of Floodplain Boundaries Using Existing Flood Hazard Data) to clarify use of this information consistent with Federal, State and County requirements. The new guidelines are outlined in Fairfax County Land Development News: Technical Bulletin 12-03.

For related information on topographic data and datum issues, see Field Notes Vol. 20, No. 6 and Vol. 17, No. 5.

For questions concerning Fairfax County floodplain mapping guidelines or to learn more about how WSSI can assist with floodplain issues affecting development your property, please contact Mike Marsala, Frank Graziano, Mike Rolband or Mark Headly.