The Corps Water Management System (CWMS) includes four interrelated models to assist with water management for the basin:
- GeoHMS (Geospatial Hydrologic Modeling Extension)
- ResSIM (Reservoir System Simulation)
- RAS (River Analysis System)
- FIA (Flood Impact Analysis)
Within the Jackson James River basin there is one USACE owned dam, Gathright Dam. The structure is located in Virginia on the Jackson River, about 43 miles upstream of the Jackson River’s confluence with Cowpasture River to form the James River. The city of Covington is about 19 miles downstream of the dam. This project is regulated to reduce flood damage downstream, to improve downstream water quality and for recreation. The reservoir has a catchment area of 345 square miles and a maximum capacity of approximately 505,000 acre-feet.
Upstream of Gathright there is a pump-back hydropower facility on Back Creek that is owned by Bath County and operated by Virginia Power. This facility has very limited flood storage and has minor impacts on inflow to the Gathright Reservoir. The only other major impounding structures in the Jackson James watershed are run of river low head dams used for water supply and power generation.
The Jackson and Cowpasture rivers confluence to form the James River just south of Iron Gate, VA. Notable tributaries on the James River upstream of Richmond are the Maury River, Buffalo River, Rockfish River, Hardware River, Slate River and Rivanna River. Some of the key gages in the basin include Jackson River below Gathright Dam near Hot Springs, VA (USGS Gage 02011800), James River at Buchanan, VA (USGS Gage 02019500), James River at Holcomb Rock, VA (USGS Gage 02025500), James River at Cartersville, VA (USGS Gage 02035000) and James River near Richmond, VA (USGS Gage 02037500).
The Jackson James River watershed begins in the Allegheny and Blue Ridge Mountains. This portion of the watershed is sparsely inhabited, forested and in mountainous terrain, characterized by parallel valleys and ridges. The River then flows east through the Piedmont region characterized by rolling hills to the flat Coastal Plain eventually discharging into Chesapeake Bay.
Average annual precipitation in Richmond, VA is along the lines of 44 inches with the wettest parts of the year in July and August.
Tidal influence on the James River occurs just east of Richmond, VA.