Civil and Environmental Engineering Commons^™

Optimizing Perennial Groundwater Yield Planning For Nonlinear Systems: Approach Comparison, Shu Takahashi, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

Four alternative simulation/optimization models useful for computing optimal sustained-yield (steady-state) groundwater pumping strategies are compared in terms of formulation, solution procedure, accuracy, and computational efficiency. The different models require different computer processing time and memory. For the aquifer tested system, if more than 10% of the cells have pumping as a decision variable, a fully linearized embedding model will require less computer memory than any other model. All the models address linear and nonlinear steady-state flow in multilayer, unconfined/confined aquifers. They also address several types of nonsmooth external flows. Newly presented are a response matrix model solving external flows described …

Optimizing Ground Water Planning And Management, Richard C. Peralta, L. S. Willardson

Civil and Environmental Engineering Faculty Publications

Simulation/optimization (S/0) models can be used to speed the process of computing long term groundwater pumping strategies. These combined models can also greatly ease the planning tasks of water management agencies. They make the process of computing optimal perennial yield groundwater management strategies fairly straightforward. S/0 models dramatically improve conjunctive water management and can help minimize the cost of groundwater contaminant clean-up. The differences between S/0 models and the simulation (S) models currently used by over 98 % of practitioners are illustrated with recent applications of S/0 models in regional planning.

Best Management Practices (Bmps) To Minimize Nitrate Leaching From Irrigated Potatoes, Ahmad Yar Ranjha, Richard C. Peralta, Robert W. Hill

Civil and Environmental Engineering Faculty Publications

Numerous preliminary simulations are again performed to determine the smallest fertilizer amount, applied througii sprinkler irrigations (chemigation), that should still yield 15.3 tons of potatoes per acre. Applying only 68 lbs/ac of ammonium nitrate fertilizer in the first irrigation on June 28, should be sufficient. Again, total crop N uptake equals potential crop N uptake throughout the growing season. Except for the net income and applied fertilizer N uptake efficiency, all the other results computed by NLEAP (Figure 4 and Table 1) are very similar to results of scenario II. Applied fertilizer N uptake efficiency is the highest (91%) in …

Optimal Groundwater Quantity/Quality Planning For Salt Lake Valley, Ali Gharbi, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

Generally, the embedding technique for optimizing groundwater management has been limited to small scale or steady-state groundwater flow management cases. The embedding approach causes sparse, highly structured constraint matrices which have been sometimes difficult to solve. Embedding applications have been limited by lack of: optimization algorithms able to easily address such matrices for large scale problems, and efficient methods for addressing common nonlinearities and converging to a solution. Computer software, USUEM, addresses these issues by: creation of alternative linear, nonlinear, combined and partitioned formulations of the same problem, implemention of an efficient cycling procedure, and good selection of optimization algorithm …

Pluman, Decision Support System For Groundwater Contaminant Plume Simulation/Optimization Management Model, Herminio H. Suguino, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

No abstract provided.

Optimal Management Of Irrigation And Vadose Zone Pesticide Transport, M. A. Hegazy, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

A management model is developed for maximizing crop yield while avoiding unacceptable pesticide leaching. Utilized constraint equations: maintain a soil moisture volume balance, describe downward pesticide transport, and limit the amount of pesticide reaching groundwater. The reported optimization model is the first which includes unsaturated zone pesticide transport. It is designed to help prevent nonpoint-source contamination of shallow groundwater aquifers. The model computes optimal irrigation amounts for given soil, crop, chemical, and climate data and irrigation frequencies. The model is tested for different irrigation scenarios. The modeling approach is promising as a tool to aid developing environmentally sound agricultural production …

Optimal Perennial Groundwater Yield Planning For The East Shore Area, Utah, Shu Takahashi, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

Computer models are developed for computing optimal perennial groundwater withdrawal strategies for the East Shore Area of Utah's Great Salt Lake. The underlying aquifer has three confined or unconfined layers. Both embedding and response matrix (RM) approaches are tested and compared. Historically, it has been difficult to incorporate simulation of an unconfined aquifer and many external flow equations described by nonsmooth functions within linear programming models. RM models normally assume system linearity. The presented RM model overcomes this difficulty using cycling and influence coefficients generated with a modified MODFLOW model. In this groundwater flow simulation model, the above nonlinear terms …

Comparing Simulated And Experimental Hysteretic Two-Phase Transient Fluid Flow Phenomena, R. J. Lenhard, J. C. Parker, Jagath J. Kaluarachchi

Civil and Environmental Engineering Faculty Publications

A hysteretic model for two-phase permeability (k)-saturation (S)-pressure (P) relations is outlined that accounts for effects of nonwetting fluid entrapment. The model can be employed in unsaturated fluid flow computer codes to predict temporal and spatial fluid distributions. Consideration is given to hysteresis in S-P relations caused by contact angle, irregular pore geometry, and nonwetting fluid entrapment effects and to hysteresis in k-Srelations caused by nonwetting fluid entrapment effects. An air-water flow experiment is conducted with a 72-cm vertical soil column where the water table is fluctuated to generate scanning S-P paths. Water contents are measured via a gamma radiation …

Optimal Sustained-Yield Groundwater Pumping Strategy For The East Shore Area, Utah, Shu Takahashi, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

Optimal sustained-yield pumping strategies were developed for the irrigated and industrialized eastern shore of the Great Salt Lake. The combined optimization and simulation model contains steady-state, finite difference, quasi-three-dimensional, groundwater flow equations embedded as constraints. The model computes the optimal spatial distribution of sustainable annual groundwater pumping rates for alternative scenarios. The addressed aquifer is a multilayer and confined/unconfined (linear/nonlinear) system. The research can help manage water in the study area, where the demand for water of sufficient quality and quantity is increasing due to urbanization.

Effects Of Alternative Sprinkler Irrigation Parameters On Pesticide Movement, Ahmad Yar Ranjha, Richard C. Peralta, Robert W. Hill, Antonio Maria Requena, Howard M. Deer, Majid Ehteshami

Civil and Environmental Engineering Faculty Publications

The relative reduction in potential ground-water contamination due to pesticides at several sites in Utah was determined by comparing alternative irrigation system designs, water management practices and pesticides. Alternative sprinkler irrigation distribution coefficients were used to estimate infiltration depths. The movement of pesticides through soils following sprinkler irrigations was simulated with one-dimensional model. Pesticide contamination of ground water can be reduced by careful selection of pesticides, properly designed irrigation systems and improved water management techniques. Procedures for selecting an appropriate sprinkler design and pesticide are presented.

Sectar: Model For Economically Optimal Sustained Groundwater Yield Planning, Richard C. Peralta, K. Asghari, R. N. Shulstad

Civil and Environmental Engineering Faculty Publications

This paper presents an approach for computing economically optimal sustained yield ground-water extract ion strategies and supportable irrigated crop acreages. Computed regional strategies maximize the present value of net economic return_ They are useful for long-term agricultural planning because they are sustainable even beyond the planning period considered within the economic optimization. The hybrid approach uses only steady-state flow equations and iterative simulation/optimization to reduce optimization memory requirements below that required by conventional models utilizing both steady and unsteady equations. SECTAR, a quadratic optimization planning model assumes heads will evolve toward optimal steady-state but does initially not know the nonlinear …

Assessing Pesticide Contamination To Groundwater: A Rapid Approach, Majid Ehteshami, Richard C. Peralta, Hubert Eisele, Howard M. Deer, Terry Tindall

Civil and Environmental Engineering Faculty Publications

A methodology has been developed for identifying hazardous pesticides/site combinations threatening ground-water contamination. Screening methodologies are required to determine which locations and pesticides now in use should receive the greatest attention to safeguard the public health. The presented method uses a hazard to ground-water hydrogeological screening model (DRASTIC) and employs a one-dimensional pesticide transport model ( CMLS). The method is an efficient and practical technique to identify where particular combinations of pesticides, water management practices, soils, and geology result in the greatest potential hazard to ground-water contamination. Use of the presented approach can reduce sampling needs and expense.

Pesticide Use On Utah's Crops, Howard M. Deer, Richard C. Peralta, Majid Ehteshami

Civil and Environmental Engineering Faculty Publications

Utah State University's Cooperative Extension Service has placed high priority on a Water Quality Initiative for Utah. As a part of that emphasis, a research project was initiated to analyze the hazards that agricultural chemicals pose to Utah's ground water. The initial phase of this research was to determine those locations in Utah that are at greatest risk of ground water contamination by pesticides. This was accomplished by interfacing data on pesticide usage with soil and hydrologic factors. The results identified specific areas in the state where potential hazards exist. This report summarizes data on the use of pesticides on …

Use Of Simplex Algorithm For Optimizing Simulation Models, M. Ehteshami, L. S. Willardson, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

A methodology and computer model is developed to determine economically optimum closed subsurface drainage systems in irrigated areas. The mode 1 maximizes net benefits, by comparing profit driven by crop yields to drain system cost and selects an optimum drain layout. The optimization methodology used is the SIMPLEX method (Nelder and Mead, 1965). The SIMPLEX model was linked to the subsurface drainage model DRAINMOD (Skaggs, 1982) and to the surface hydraulic model KINE (Walker and Skogerboe 1987). The selected optimum drainage system maximizes the difference between total revenue, and the total cost of installation, operation and management of a particular …

Modelling For Potentiometric Surface Management Of Multilayer Aquifer Systems, A. Gharbi, Richard C. Peralta, K. M. Waddell

Civil and Environmental Engineering Faculty Publications

Assuring the long-term availability of groundwater of adequate quality and quantity frequently requires the implementation of appropriate ground-water and conjunctive water management strategies. Presented is a model for developing optimal strategies for an multilayer aquifer in which stream-aquifer interflow is affected by the potentiometric surface and ground-water use. The model is applied to the Salt Lake Valley. Discussed is the use of pumping to control: l) potential migration of non-point source agricultural contaminants between aquifer layers and 2) the movement of a mile-long plume caused by mining waste.

Effects Of Alternative Furrow Irrigation Parameters On Pesticide Movement In Cropped Areas In Utah, Antonio Maria Requena, Ahmad Yar Ranjha, Richard C. Peralta, Howard M. Deer, Majid Ehteshami, Robert W. Hill

Civil and Environmental Engineering Faculty Publications

Production of adequate supplies of food and fiber currently requires that pesticides be used to limit crop losses caused by insects, pathogens, weeds and other pests. Although pesticides are necessary in today' s agriculture, they can be a serious problem if they reach and contaminate ground water, especially where drinking water needs are met by ground water. The relative reduction of potential ground-water contamination due to agricultural use of pesticides was analyzed for particular sites in Utah. The potential reduction of pesticides in ground water was considered by utilizing alternative irrigation systems, water management practices and pesticides. A one-dimensional simulation …

Modeling Of Multicomponent Organic Chemicaltransport In Three Phase Porous Media, Jagath J. Kaluarachchi, J. C. Parker

Civil and Environmental Engineering Faculty Publications

A two-dimensional finite-element model was developed to predict coupled transient flow and multicomponent transport of organic chemicals which can partition between nonaqueous phase liquid, water, gas and solid phases in porous media under the assumption of local chemical equilibrium. Gas-phase pressure gradients are assumed negligible and liquid flow equations are solved simultaneously using an upstream weighted solution method with time-lagged interphase mass-transfer terms and phase densities. Phase-summed component transport equations are solved serially after computation of the velocity field also by an upstream weighted finite-element method. Mass-transfer rates are evaluated from individual phase transport equations by back-substitution and corrected for …

A Numerical Model For Areal Migration Of Water And Light Hydrocarbon In Unconfined Aquifers, Jagath J. Kaluarachchi, J. C. Parker, R. J. Lenhard

Civil and Environmental Engineering Faculty Publications

A finite element model has been developed to simulate simultaneous flow of water and light hydrocarbon in an areal flow region of an unconfined aquifer for analyses of hydrocarbon spreading from subsurface leaks or spills and for use in design of free product recovery systems. Vertically integrated governing equations for water and oil flow are employed which assume local vertical equilibrium and negligible gas pressure gradients. Multiple water and free product recovery wells are handled as internal type-I boundary conditions by stipulating air-oil table elevation and free product height with corrections to convert grid averaged nodal heads to actual well …

Drastic Indices For Selected Agricultural Areas In Utah, Ahmad Yar Ranjha, Richard C. Peralta, Majid Ehteshami

Civil and Environmental Engineering Faculty Publications

The main objective of this report is to present contour maps of DRASTIC indices for selected areas in Utah. In general, the higher the DRASTIC index value, the greater the potential for ground-water pollution. The acronym DRASTIC is derived from the following hydrogeologic factors which affect vertical movement of water through the soil, and hence affect downward movement of contaminant.

The Policy Process: Cooperation As An Initiative In Utah, Richard C. Peralta, Ann W. Peralta

Civil and Environmental Engineering Faculty Publications

No abstract provided.

Reconnaissance-Level Alternative Optimal Groundwater Use Strategies, Richard C. Peralta, Bithin Datta

Civil and Environmental Engineering Faculty Publications

This study develops regionally optimal ground-water extraction strategies. Alternative explicit planning objectives arc: (1) Maximize total pumping from the underlying aquifer while causing the evolution of a steady potentiometric: surface: and (2) maintain a prespecified target potentiometric surface. Implicit objectives involve controlling stream/aquifer interflow and water flow across a state boundary, and attempting to avoid poss disruption of current cropping patterns. Models, bounds, constraints, and data arc: formulated. Alternative optimal strategies and the rationale for preferring one strategy arc: presented for a region in Arkansas. The objective of maintaining the relatively unstressed target potentiometric: surl1ce yields politically and socially unacceptable …

Exeis, Expert Screening And Optimal Extraction/Injection Pumping Systems For Short-Term Plume Immobilization, R. L. Ward, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

This report presents the EXEIS family of micro-computer based programs for achieving short-term contaminant plume containment. EXEIS is applicable if contaminated water cannot be extracted and water cannot be imported to or exported from the site. There are two main purposes and types of users. For persons relatively unfamiliar with groundwater remedial actions, an expert screening system gives guidance concerning whether extraction/injection (Eli) pumping, slurry wall or sheet piling are most appropriate. For personal more experienced in remedial actions, management models compute optimal E/I strategies for short-term containment. Via deterministic and stochastic multiobjective optimization models, uncertainty in both planning horizon …

Optimal Conjunctive Use Of Ground And Surface Waters, Richard C. Peralta, A. Gharbi, L. S. Willardson, A. W. Peralta

Civil and Environmental Engineering Faculty Publications

Conjunctive water management involves coordinating the use of groundwater and surface water in time and in space. The water sources might or might not be in hydraulic connection with each other. In this chapter, conjunctive water use involves the combined use of surface and groundwater to supply crop water needs.

Two simplified examples of conjunctive use follow. Farmer Allen uses river water to irrigate his crops. In dry years, with below average stream flow, his surface water supply is severely limited by late summer. To augment this surface water supply, he pumps groundwater. In wet years, when the surface water …

Conjunctive Water Use/Sustained Groundwater Yield Planning: Case History, A. R. Yar, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

A methodology for computing perennial ground-water yield and conjunctive water use strategies is presented, using the Arkansas Grand Prairie as a case study. This includes development and use of an optimization model for computing sustainable ground-water pumping strategies and a post-processor for allocating ground-water and surface water supplies in time and space. The optimization model utilizes embedded finite difference flow equations as constraints and bounds on pumping, recharge and potentiometric head. Computed conjunctive use strategies will maintain, as much as possible, the existing stressed potentiometric surface. They will also assure at least 6 meters of saturated thickness in all locations …

Pesticide Movement And Water Management, Majid Ehteshami, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

Agricultural chemicals are essential components of agricultural production systems in the United states. Pesticides control weeds, insects, and have had an important role in increasing agricultural productivity in the last 50 years, despite diminishing crop land acreage. The benefits of chemicals use options in agriculture must be balanced against potential contamination of surface water and ground water resources. This study shows the effect of water management practices on pesticide movement and its potential pollution to ground water. It indicates that careful use of pesticides, water management practices and irrigation system design alternatives could cause a major reduction in ground water …

Water Resources Development Alternatives For The Mississippi Alluvial Plain In Eastern Arkansas, Gary L. Mahon, John E. Terry, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

Effective management of the water resources of the Mississippi Alluvial Plain in eastern Arkansas involves understanding the nature of existing problems, estimating total water demands, predicting how much of the total demand can be provided by the underlying aquifer and available surface-water sources, and deducing how much water must come from alternate sources. Various Federal and State agencies have cooperatively provided hydrologic information for the area to evaluate water-resources development alternatives ensuring that (1) the use of water from the aquifer be maximized while maintaining a minimum of 20 feet of saturated thickness, (2) the use of surface water be …

Application Of Bmp For Prevention Of Ground-Water Contamination, Majid Ehteshami, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

The use of pesticides is an integral part of today's agriculture. In many cases, pesticides safeguard crops from severe pest infestation, or increase yield by suppressing competing weed growth. Pesticides often make the difference between profits and losses in farming operations. However, pesticides, even in extremely low concentrations, can pose a risk to human health and to the environment. Applied to plant or soil surfaces, or injected into the soil, pesticides may leach to the ground water or may be washed off with surface water. Pesticide contaminated surface water can reach ground water, or contaminated ground water can reach the …

On-Farm Reservoir Construction In The Grand Prairie Region Of Arkansas: An Engineering Economic Analysis, Jayson K. Harper, Richard C. Peralta, Robert N. Shulstad

Civil and Environmental Engineering Faculty Publications

No abstract provided.

Agricultural Pesticide Hazard To Groundwater In Utah, Hubert Eisele, Majid Ehteshami, Richard C. Peralta, Howard M. Deer, Terry T. Tindall

Civil and Environmental Engineering Faculty Publications

We gratefully acknowledge the funding support of the Utah Department of Agriculture and the following offices at Utah State University. The Department of Agricultural and Irrigation Engineering, the International Irrigation Center, the Department of Animal, Dairy and Veterinary Sciences, the Department of Soil Science and Biometerology, and the University Extension Services.

Computational Aspects Of Chance-Constrained Sustained Groundwater Yield Management, R. R.A. Cantiller, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

A methodology for including chance-constraints in models for maximizing regional sustained-yield groundwater extraction is presented. The procedure utilizes the spatially distributed mean and variance of saturated thickness in a confined aquifer. This data is derivable from kriging, a geostatistical technique. The technique is applied to a scenario of somewhat egalitarian agricultural development dependent on groundwater. Decision makers in this situation know that groundwater availability is insufficient to supply all potential demand. They plan to implement a sustained yield groundwater extraction strategy. They know that because of uncertain knowledge of aquifer parameters, at some point in the future, available groundwater in …