- A computer model is developed to estimate the initial investment and annual operating costs of feedlot runoff control systems. Costs are estimated for complete control systems consisting of a retention pond, settling basin, clean water diversion-runoff collection structures, disposal site, and an irrigation system. The model requires design inputs and cost inputs. Design inputs consist of: feedlot area, pumping rate, retention pond volume, disposal site area, and average
pumping days per year. Cost inputs consist of market prices for system components and service costs. The model is used to estimate the initial investment and annual operating costs of runoff control systems capable of complying with proposed Federal water pollution regulations for open beef feedlots. Design parameters for these systems are those developed by Wensink and Miner (1977). Runoff control costs are estimated for one, ten, and 100 acre feediots at seven U.S. locations. For the purpose of cost comparison, budgets are estimated for systems using: four different irrigation systems, 5 pumping rates, seven management alternatives, and two disposal policies. The resulting data are analyzed to determine how investment and operating costs were affected by the following seven criteria: pumping rate, feedlot size, geographic location, management alternative, disposal policy, irrigation system, and operator convenience. Estimated runoff control costs are compared to current costs of producing fed beef. The additions to current cost of production are estimated to be insignificant for larger feedlots (10-100 acres).
Small feedlots (1 ac) face costs ($/head of capacity) ranging from three to ten times as high as those estimated for larger lots. The second part of the analysis deals with the cost of controlling alternative levels of runoff, (lower than specified by federal regulations), at a specific site. Twenty systems, whose pumping rates and pond volumes represented 0, 5, 10, ..., 100% of those necessary to meet federal standards, were budgeted for a 100 acre feedlot at Pendleton, Oregon. The cost data is compared to the performance of the systems, as measured by the percent of total runoff estimated to be controlled over the time period 1914-1971. A computerized watershed model developed by Wensink and Miner (1975) is used to simulate the performance (amount of runoff controlled) of the systems. The resulting cost-performance data indicate significant cost reductions can be achieved with only minor increases in uncontrolled
runoff. A 5% increase in uncontrolled runoff is coupled with a 25% reduction in required investment; increasing uncontrolled runoff by 10% results in a 40% reduction in required investment.