The Corps of Engineers studied several plans in order to select the best alternative. Options determined to be not feasible, unacceptable or which did not meet the needs of the area, were not considered during re-evaluation of the plans.
Alternative 1– No Action
With no action taken only 22 percent of the land that is currently irrigated would remain viable for irrigated agricultural use. This alternative was used as the basis for comparing all other alternatives.
Alternative 2 – Additional Storage
This plan outlined the construction of additional on-farm storage reservoirs without a water import system or conservation measures in place. Initial studies indicated irrigation water available for use on a farm might actually decrease if additional reservoirs were built without a source for any addition supply of water. The analysis showed that farmers in the Grand Prairie are already capturing a high percentage of the rainfall available. Building more reservoirs would not allow existing reservoirs to be filled to capacity and would increase water loss due to evaporation and infiltration as water is spread over more surface acreage. Further, additional reservoirs could only be filled in wet years without import water.
Alternative 3 – Conservation with Storage
This plan called for conservation measures without any import water to be implemented to maximize the use of existing water resources. Conservation measures would result in only 31 percent of the land remaining useable for irrigated agriculture.
Alternative 4 – Import System and Conservation without Additional Storage
This alternative couples conservation measures (without additional reservoirs) with an import system, which diverts water from the White River. Studies conducted by the National Resources Conservation Service (NRCS) showed that desired conservation impact could not be achieved without additional storage.
Alternative 5 – Combination Conservation, Storage and Importation of Water
This plan combines conservation, increased on-farm storage and a 1,800 cubic feet per second water import system. Arkansas state law limits potential water withdrawals.
Alternative 6 – Combination Alternative Plus Additional Storage
This plan was the same as the one listed above, but included 25 percent more storage capacity. According to studies by the NRCS, increased levels of on-farm storage above the optimum level were not considered feasible. Any increased benefit provided by additional storage was more than offset by the cost of building the storage facility.
Alternative 7 – Combination Alternative and Optimization of the Import System
This plan was the same as Alternative 5, except this plan optimizes the import system. Prior alternatives were used to optimize the on-farm components such as conservation measures and storage. In order to optimize the import system, on-farm components were held constant and four different import systems: 7A – 1,480 cubic feet per second import system, 7B – 1,640 cubic feet per second import system, 7C – 1,800 cubic feet per second import system, and 1,900 cubic feet per second import system. All were evaluated as separate alternatives.