Browsing by Author "Ellis, J. R."

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Economic Implications of Farmer Storage of Surface Water in Federal Projects: Elephant Butte Irrigahon District, Dona Ana and Sierra Counties, New Mexico
(Texas Water Resources Institute, 1982-12) Lacewell, R. D.; Teague, P. W.; Ellis, J. R.
This study estimated the expected regional impact and economic feasibility of a proposed water accumulation or water saving option for agricultural producers operating in the Elephant Butte Irrigation District in southern New Mexico. The water accumulation plan would allow agricultural producers to retain part of a given year's surface water allocation in Elephant Butte Reservoir, providing use of the unevaporated portion in a later year. The analysis was based upon modeling of current cropping practices subject to regional resource constraints within a static linear programming model. Pertinent input/output coefficients and costs were incorporated, with five-year (1976-1980) average output prices assumed for twelve crops spread across 11 soil groups. Applicable fixed costs and interest charges were taken into account. Net returns to the region were maximized assuming 1 and 3 acre-feet of groundwater available per year per acre irrigated. Surface water availability was varied from zero to 3 acre-feet per acre to obtain schedules depicting regional net returns and cropping patterns for varying surface water allocations for both the groundwater situations examined. These schedules were then used to build temporal linear programming models which maximized the present value of net returns for the period 1963 to 1980 subject to historical surface water allocations and reservoir evaporation rates. Calculation of these evaporation rates took into consideration increased lake levels due to surface water storage. The temporal models were used to estimate an optimal allocation of surface water over the 18 year period investigated for the two groundwater availability situations considered. Returns for the optimal surface water allocations were then upper bounds on potential net returns to the region. Projected streams of net returns were also obtained for each of the scenarios analyzed; i.e., optimal temporal allocation of surface water, 2 acre feet of surface water per year limit and actual allocation of surface water given the 1 and 3 foot groundwater limitations. These streams of net returns were valued in 1980 dollars allowing comparison among the alternative scenarios. Differences between the various returns streams for each groundwater situation provided a measure of possible economic effects of the water saving program. Results of the study for current groundwater availability conditions indicate that optimally temporal allocated surface water use would increase average annualized net returns per acre from that of the actual surface water allocation by .82 dollars per year, or less than .2 %. Use of the more realistic two acre-foot per acre limit on surface water use led to an increase in annualized net returns of only .23 dollars per acre per year. Both increases were deemed insufficient to cover anticipated administrative costs of the program. Under conditions of limited groundwater availability (1 acre-foot per acre), percentage increases in annualized net returns over those for the actual surface water allocation were more significant. Use of the water saving option and perfect knowledge of future surface water allocations resulted in increased annualized net returns of $8.41 per acre per year for an increase of 54 z. For the two acre-foot surface water use limitation case, annualized net returns increased by $3.68 per acre per year (23.7 %). In all cases considered, groundwater use increased with use of the water saving option. These economic results, coupled with possible political obstacles faced by the program, suggested that alternative water management schemes should be considered.
Impact of New Irrigation Technology on the Texas High Plains: 1980-2020
(Texas Water Resources Institute, 1983-12) Ellis, J. R.; Lacewell, R. D.; Reneau, D. R.
Crop production on the Texas High Plains is constrained by limited and erratic rainfall, hence irrigation is important. Presently, 6 million acres, or 50% of regional cropland, are irrigated annually. Irrigation water is drawn from the Ogallala Aquifer, which has a recharge rate near zero, and is being depleted at the present rate of use. Future crop production is dependent on technology, as well as the resources available. Because water is a major limiting resource, technologies that increase plant available water, such as advanced irrigation distribution systems and soil moisture conserving tillage methods, are of particular interest, and are the focus of this study. Two levels of analysis were included. The first, a farm level analysis based upon representative counties showed the similarities and differences of response given particular resource endowments, technological options and price situations. Part of the analysis considers the impact of annual qroundwater withdrawal constraints on discounted net present value for a forty year planning horizon. The discounted net revenue was higher for lower discount rates, better commodity prices, and more advanced technology. However, alternative discount rates, prices, and technology did not change the optimum annual withdrawal limit. Lower initial groundwater resources reduced the revenue level and the optimal annual groundwater decline limit. The other part of the farm firm analysis covers expected costs, returns and cropping patterns for a single period. Prices have a significant influence on production, but a far greater impact on net returns. The value of production is 64% to 85% higher for normal prices versus low prices, while net returns are from 8 to 30 times higher. The amount of available groundwater was not as important as price in the determination of production levels, but it too had a significant impact on net returns. Comparing across representative counties, with prices, technology and groundwater situations held constant, the value of production varied more than $150 per acre, but net returns changed very little. The value of production increases 17% with advanced technology, but net revenue more than doubles. The second level of analysis, a regional analysis, addressed expected changes in cropland use, groundwater pumpage, production levels, input demand, and farm income over the next forty years, under select technology and price assumptions. Water availability and hence use, drops over time, reducing irrigated cropland, gross returns and net revenue. The demand for other inputs does not decline as quickly as water usage, indicating input substitution. Further, the decline in net revenue is greater than the reduction in gross returns or variable costs of production. The intensity of crop production declines and the mix of crops changes, reducing purchased input demand and lowering regional farm income. Advanced technology enhances the value of the groundwater resource, increasing water use especially in the later periods of the time horizon. Nontheless, over the whole 40 years, technologies which improve dryland, as well as irrigated, crop production, such as limited tillage and crop rotations, have a greater impact than advanced irrigation technology. While advanced technology enhances productivity and increases net returns, technology is not a substitute for irrigation. Nor does technology save groundwater resources in the large, since the increased value of the water, given advanced technology, encourages greater use, overall. Advanced technology, however, is important to the future of crop production in the region, since it increased the level of production, and net revenue. Further, the impact of technology was proportionally greater under the low commodity price scenarios than for average prices.
Recursive Programming Model for Crop Production on the Texas High Plains
(Texas Water Resources Institute, 1984-02) Ellis, J. R.; Lacewell, R. D.; Reneau, D. R.
A flexible, recursive programming model of crop production on the Texas High Plains was developed. Besides the linear programming (LP) Optimization routine and recursive feedback section, the model also includes a matrix generator and report writer to make scenario definition and output analysts faster and easier. The production activities for each run of the model, are defined for one acre of a specific crop or crop rotation, irrigated at particular times, using a chosen irrigation distribution system and tillage method, on a given land class. The irrigation level may be zero (i.e. dryland) and the land class can include terracing when appropriate. The objective function for the LP optimization routine is the maximization of net returns (gross returns minus all variable, or variable and fixed, costs) to land, water and management. For static runs, the maximization includes net returns over variable costs only; for temporal runs, over variable and fixed costs. LP constraints include land by soil class, irrigation water availability for each of 18 irrigation periods and a total annual water use constraint. The model can be run as either a static single period optimization or as a recursive, temporal model When operated in the recursive mode, the model will loop through up to 20 iterations, rebuilding the LP matrix for each iteration and writing a report for each period. The feedback section of the recursive model is used to update the groundwater situation after solution of each iteration. The amount of groundwater used is summed and that usage translated into the reduction in aquifer saturated thickness, increased pump lift and reduced well yield per period. The new groundwater situation plus any inputted changes in prices, technical efficiencies or crop yields form the data, from which the production activities and constraints for the next iteration are built. At the end of the prescribed number of iterations, a summary report covering the whole time horizon is written and the discounted present value of net returns is calculated at three prescribed discount rates.