Fulton County WRSIS site schematic
The Fulton County, Ohio site has two 8.1 ha (20 acre) fields, one that is subirrigated and the other a control plot with drain pipe for subsurface drainage only (fig. 4). Drain pipes within the subirrigated field are spaced about 4.6 m (15 ft) apart, with two newer 10 cm (4 in.) diameter corrugated plastic tubing drain lines placed between each of the existing drains comprised of 10 cm (4 in.) diameter clay tile. The control plot contains only the clay tile lines and the spacing is 13.7 m (45 ft). To regulate the subirrigated field ground water levels, three hydraulic control structures were installed. This provides three separate water table management zones within the subirrigated field (fig. 4).
Subsurface drainage from both fields is routed by gravity to a 0.57 ha (1.4 acre) wetland having a storage capacity of 3790 m3 (1.0 million gal). There is very little surface runoff that enters the wetland. Water transfer between the wetland and a 0.64 ha (1.57 acre), 8706 m3 (2.3 million gal) capacity reservoir occurs via a 3.7 kW (5 hp) submersible pump or a 1.5 kW (2 hp) submersible pump, both located within an adjacent concrete sump. Either pump can also be used to route water to the field when the system is in subirrigation mode. A stream running between the wetland and reservoir provides additional water supply for subirrigation.
The Fulton County, Ohio WRSIS site was completed by local contractors during spring 1996 at a total capital cost of $60,100 U.S. Corn and soybeans are grown predominantly on Nappanee loam (mesic Aeric Ochraqualfs). From particle size analysis of samples taken at the surface, percent sand was 17% to 66%, silt ranged from 12% to 37%, and the amount of clay was between 20% and 46%. Saturated horizontal hydraulic conductivity values measured with a velocity permeameter ranged from 4 x 10-4 cm/s (0.6 in./hour) near the surface to 7 x 10-5 cm/s (0.1 in./hour) through the rest of the soil profile down to a depth of 1.2 m (4.0 ft).