Conjunctive use, irrigation management, water resources development
A computer simulation model, named Arkansas Offstream Reservoir Analysis (ARORA) was developed to simulate present worth of net income from soybean production systems for conditions varying with respect to ground water availability, offstream reservoir capacity, and many other variables. Additional algorithms were incorporated into the model to enable it to optimize reservoir dimensions given realistic constraints and to identify the reservoir capacity corresponding to maximum present worth of simulated net income. The model was written in FORTRAN programming language and requires significant input data in order to provide significant flexibility with respect to the situations which may be accomodated. The model was demonstrated using 210 hypothetical situations which varied in terms of ground water availability, initial saturated depth of the aquifer, rate of decline of potentiometric surface, interest/discount rates, soil, and soybean price. The results were very reasonable and clearly point out that all of these variables impact optimal reservoir capacity, although no single variable is the sole determining factor in the decision of whether or not to construct a reservoir. The results further indicate that depending on model accuracy, there are many scenarios in which construction of a reservoir would be to the best interests of a soybean producer - especially those in regions with no ground water available or with a saturated aquifer depth of 25 ft or less.
Edwards, D. R. and Ferguson, J. A.. 1990. Optimal Reservoir Design Criteria in Conjuctive use of Surface Water and Groundwater for Soybean Irrigation in Eastern Arkansas. Arkansas Water Resources Center, Fayetteville, AR. PUB145. 129