The 2014 Virginia General Assembly passed (House Bill 1006 and Senate Bill 582) and the governor approved on April 1, 2014 (Chapters 475 and 489 of the 2014 Virginia Acts of Assembly) legislation that authorized a new Virginia Probable Maximum Precipitation Study to be completed by Dec. 1, 2015. The legislation directed “[t]hat the Department of Conservation and Recreation, on behalf of the Virginia Soil and Water Conservation Board, shall utilize a storm-based approach in order to derive the Probable Maximum Precipitation (PMP) for locations within or affecting the Commonwealth. The PMP revisions shall be based on accepted storm evaluation techniques and take into account such factors as basin characteristics that affect the occurrence and location of storms and precipitation, regional and basin terrain influences, available atmospheric moisture, and seasonality of storm types. The results shall be considered by the Virginia Soil and Water Conservation Board in its decision to authorize the use of the updated PMP values in Probable Maximum Flood calculations, thus replacing the current PMP values.”
In accordance with this legislative direction, Applied Weather Associates (AWA), on behalf of the Virginia Soil and Water Conservation Board, completed a statewide PMP study for Virginia. A technical review board of experts, with additional ad-hoc participation by cooperating state and federal agencies, was established by DCR to provide advice and expertise throughout the development of the study. That board met to review and discuss study progress and results in July and November of 2014 and April and October of 2015 and accepted AWA’s estimates for PMP for Virginia.
See also: Probable Maximum Precipitation Study and PMP Evaluation Tool