Specific-capacity, storage-coefficient, and specific-yield data for wells in West Virginia were compiled to provide a data set from which transmissivity could be estimated. This data can be used for analytical and mathematical groundwater flow modeling. Analysis of available storage-coefficient and (or) specific-yield data indicates the Ohio River alluvial aquifer has a median specific yield of 0.20, which is characteristic of an unconfined aquifer. The Kanawha River alluvial aquifer has a median specific yield of 0.003, which is characteristic of a semi-confined aquifer. The median storage coefficient of fractured-bedrock aquifers is only 0.007, which is characteristic of confined aquifers.
The highest median transmissivity of a specific aquifer in West Virginia occurs in Ohio River alluvium (4,800 ft2/d); the second highest occurs in Kanawha River alluvium (1,600 ft2/d). The lowest median transmissivity (23 ft2/d) is for the McKenzie-Rose Hill-Tuscarora aquifer. Rocks of Cambrian age within the Waynesboro-Tomstown-Harpers-Weverton-Loudon aquifer had a low median transmissivity of only 67 ft2/d. Other aquifers with low transmissivities include the Hampshire Formation, Brallier-Harrell Formations, Mahantango Formations, Oriskany Sandstone, and the Conococheague Formation with median transmissivities of 74, 72, 92, 82, and 92 ft2/d, respectively. All other aquifers within the State had intermediate values of transmissivity (130-920 ft2/d). The highest median transmissivities among bedrock aquifers were those for aquifers within the Pennsylvanian age Pocahontas Formation (1,200 ft2/d) and Pottsville Group (1,300 ft2/d), and the Mississippian age Mauch Chunk Group (1,300 ft2/d). These rocks crop out primarily in the southern part of the State and to a lesser extent within the Valley and Ridge Physiographic Province in West Virginia's Eastern Panhandle.
The highest mean annual ground-water recharge rates within West Virginia (24.6 in.) occur within a band that extends through the central part of the State within the eastern part of the Kanawha River Basin. This area of relatively high relief has peaks higher than 4,000 ft and precipitation greater than 50 in./yr. The band of high recharge rates extends northward towards Pennsylvania and includes the Monongahela River Basin, which has a mean annual recharge of 21.4 inches.
To the west of this central band lies a region of lower relief with much lower mean annual precipitation rates. Mean annual recharge for the Tug Fork, Twelvepole Creek, and Guyandotte River Basins is only 12.6 inches. For the western part of the Kanawha River Basin, mean recharge is 11.9 inches. The lowest mean annual recharge rates (8.4 in.) within the State occur in the Little Kanawha River Basin and the tributary streams in the region that discharge directly to the Ohio River.
West Virginia's Eastern Panhandle is an area characterized by long linear northeast to southwest trending ridges and valleys. The mean annual ground-water recharge rate for this region, which is drained almost entirely by the Potomac River and its tributaries, is 9.4 inches. This area, which is located within a rain shadow resulting from orographic lifting in the higher altitude area to the west, receives less precipitation (approximately 30 in.) than the region to the west.