IRRIGATION DEVELOPMENT AND MANAGEMENT ALTERNATIVES OF A DOLOMITE AQUIFER IN NORTHEASTERN ILLINOIS1

ABSTRACT: Irrigation development of the dolomite aquifer in eastera Kankakee and northern Iroquois Counties, Illinois, is extensive and increasing. Interruptions of domestic supplies have been reported with increasing frequency during the 1980's. To address this issue, a regional assessment of the ground-water resources of the region was conducted in 1987 and 1988. Options for managing the dolomite aquifer were also investigated. Hydrogeology of the dolomite aquifer was determined using five aquifer tests. Tranamissivity values of the dolomite aquifer ranged from 14,000 to 50,000 gpd/ft (168 to 600 m³/m/day). Storage coefficients were between 0.0001 and 0.0002, within the range of a confined (artesian) aquifer. Based on flow-net analyses, recharge of the dolomite aquifer ranged from 85,000 to 285,000 gpd/mi² (124.4 to 417.0 m³/day/km²). Water levels of the dolomite aquifer were mapped during five periods in 1987 and 1988 by measuring up to 226 wells completed in the dolomite aquifer. Maximum regional water-level declines because of irrigation pumpage were 44 feet (13.4 m) in 1987 and 72 feet (21.9 m) during the drought of 1988. Based on ground-water use data, precipitation records, and hydrogeologic information, the magnitude of water-level declines can be attributed more to differing hydrogeologic conditions than to pumpage or climatic changes. Existing ground-water management methods for resolving conflicts over the ground-water resources of the study area are reviewed and alternative management options explored.     

OPTIMIZATION OF WATER RESOURCES FOR IRRIGATION IN EAST JORDAN1

The paper describes an approach towards optimal allocation of surface and ground water resources to three agricultural areas in the Jordan Valley under conditions of scarce water supply. The optimizing model allocates water from three main rivers, each with reservoir storage, and from two ground water sources to three irrigation regions. Productivity of irrigation water, expressed as the net present value of the regional agricultural output, but allowing for crop water deficits, is first maximized using nonlinear programming. The allocation process then adopts techniques of linear programming to determine the least cost alternative based on the unit cost of water from each resource at each destination, as it varies with time.     

POTENTIAL IMPACT OF IRRIGATION ON WATER RESOURCES IN THE LITTLE WABASH BASIN OF ILLINOIS1

The level of water demand for supplemental irrigation and the impact of such demand on water supplies were estimated, as a function of the price of corn (Zea Mays L.). The method of estimation was based on an economic analysis of irrigation practice which assumed constant irrigation costs, profit maximizing behavior on the part of irrigators, and which was deliberately structured to underestimate the level of irrigation water use. The analysis was applied to and used data from the Little Wabash basin in Illinois. No irrigation was predicted at a corn price below $3.50 per bushel. Between $3.50 and about $6.50 per bushel, irrigation was estimated to be profitable for a small region of the basin where acceptable groundwater was available. Above about $6.50 to $7.50, irrigation was found to be profitable in the remainder of the basin, where impoundment storage was required. The potential impact on the water resources of the basin is significant. For a corn price between $3.50 and about $6.50, the probability of a shortfall, defined as the event where the potential demand exceeds the supply, was estimated to be between 2 percent and 20 percent during the growing season. Above about $7.50, this probability was found to be about one-third. The development of policies to control withdrawals for irrigation and other uses is endorsed.     

REUSE OF POWER PLANT COOLING WATER FOR IRRIGATION1

ABSTRACT: Current water quality policies in California require disposal of saline blowdown waters from power plants in sealed evaporation ponds to avoid degradation of ground waters. This policy highlights the conflict between increased energy demands, increasing scarcity of water, and environmental priorities. Saline blowdown waters can be used for the irrigation of salt tolerant crops, albeit with some reduction in yields. The results of experiments intended to specify these yield reductions are reported. If such irrigation is carefully managed, the soil profile can be used to store residual salts and ground water degradation will be avoided, provided that irrigation ceases before the salts are leached to the ground water. An analysis of discharge below a carefully managed irrigation project shows that the downward movement of salts below the root zone is no worse than with conventional methods of disposal. Thus, irrigation reuse with blowdown water is shown to be a viable means of saline water disposal while maintaining existing standards of ground water quality protection. Further analysis demonstrates the economic feasibility of such irrigation reuse by showing that it is significantly less costly than the evaporation pond alternative.     

ESTIMATING THE DEMAND FOR IRRIGATION WATER IN THE CENTRAL VALLEY OF CALIFORNIA1

ABSTRACT: This paper computes estimates of the demand for surface irrigation water directly from disaggregated profit functions for fields in the San Joaquin Valley of California. It finds that treating delivered surface water and pumped ground water as separate, imperfectly substitutable inputs to production matters a great deal. We find substantial ranges of inelastic demand for delivered water, and thresholds across which demand then becomes highly elastic. The results imply that moves toward freer water markets could lead to large quantities reallocated from agriculture to urban uses in the Western U.S., but would require large price increases and would induce extensive ground water mining and major changes in cropping patterns. While these results are dependent on our particular model and simplifying assumptions, evidence exists that they may be robust.     

REGIONAL WATER SUPPLY PLANNING STUDY FOR NORTHEASTERN ILLINOIS1

ABSTRACT: The development of a regional water supply system for the six-county area of Northeastern Illinois is presented in this paper, including: 1) the establishment of regional water supply technical planning policies; 2) the development and utilization of a regional water supply computer model to identify the principal and secondary sources of water supply for each entity in the study area, based on an apparent cost-effective source analysis; and 3) utilization of the study results to develop for the year 2010 a suggested preliminary regional water supply system. Using the findings from task 2 above, a proposed plan for overall Lake Michigan water use through the year 2010 was also developed. The effects of the proposed regional water supply system on future water levels in the deep aquifer were also discussed.     

MOTIVATING REDUCTIONS IN DRAIN WATER WITH BLOCK-RATE PRICES FOR IRRIGATION WATER1

ABSTRACT: Increasing block-rate prices for irrigation water were implemented during 1989 in a 10,000-acre irrigation district in California's San Joaquin Valley. The program motivated improvements in irrigation practices that reduced the volume of water delivered to farm fields and the volume of drain water collected in on-farm drainage systems. The ratio of net crop water requirements to field deliveries increased from 0.65 in 1988 to 0.73 in 1989. The volume of drain water collected at a subset of 20 drainage systems was reduced by 351.1 acre-feet (11.5 percent). Estimated loads of salt, boron, and selenium were reduced by 2,407 tons (11.0 percent), 3.33 tons (11.0 percent), and 0.07 tons (9.2 percent).     

SOIL MOISTURE SENSORS FOR URBAN LANDSCAPE IRRIGATION: EFFECTIVENESS AND RELIABILITY1

ABSTRACT: Granular matrix soil moisture sensors were used to control urban landscape irrigation in Boulder, Colorado, during 1997. The purpose of the study was to evaluate the effectiveness and reliability of the technology for water conservation. The 23 test sites included a traffic median, a small city park, and 21 residential sites. The results were very good. The system limited actual applications to an average of 73 percent of the theoretical requirement. This resulted in an average saving of $331 per installed sensor. The sensors were highly reliable. All 23 sensors were placed in service at least three years prior to the 1997 study during earlier studies. Of these, only two had failed by the beginning of the 1997 study, both due to external factors. Including replacement of these failed sensors, the total repair cost for the 1997 irrigation season was less than $270. The effort required to maintain each system was small, only about 6–7 minutes per visit. Each site was visited weekly for this study, but less frequent visits could be made in practice. The sensors observed in this study performed well, significantly reduced water consumption, and were easy to monitor and maintain. Soil moisture sensors appear to be a useful and economical tool for urban water conservation.     

ALLOCATION MODEL FOR IRRIGATION WATER COST: CASE STUDY OF THE NILE VALLEY IN EGYPT1

ABSTRACT: An allocation model for irrigation water cost, based on the Use of Facilities method, is presented. The model is developed for large-scale irrigation systems which may include multipurpose reservoirs, irrigation control works, pump stations and irrigation canals of various orders. The model accounts for the water conveyance losses as well as the water gains in the irrigation canals, and their effects on irrigation cost. It is applied to the irrigation distribution system of the Nile Valley in Egypt, which contains the High Aswan Dam, 16 irrigation structures, 12 pump stations, and numerous irrigation canals. The irrigation water cost at 29 areas representing the Nile Valley is determined.     

WELFARE IMPLICATIONS OF TUBEWELL IRRIGATION IN BANGLADESH1

ABSTRACT: This paper investigates and estimates the welfare loss due to monopoly in tubewell irrigation water market in Bangladesh. In this context, an attempt has been made to evaluate the efficacy of the landless irrigation groups. Using cross-sectional data and regression analysis, cost and demand functions for irrigation water are estimated. The study demonstrates the relatively superior performance of the landless groups in terms of economic efficiency in shallow tubewell irrigation operation, in comparison to irrigation operation by the landowners.     

PERCOLATE WATER AND BROMIDE MOVEMENT IN THE ROOT ZONE OF EFFLUENT IRRIGATION SITES1

ABSTRACT: A bromide tracer was used to evaluate percolate water and ion movement in the upper 1.2 m of soil at a proposed sewage effluent irrigation site located in the Missouri Ozarks. Two plots representing Doniphan silt loam and Crider silt loam soils were sprinkler irrigated with local ground water at a rate of 7.62 cm/week from June through August 1976. Soil water potential, percent soil moisture by volume, and background levels of bromide in soil water, ground water, and precipitation were measured at the study plots. Bromide exchange properties and saturated hydraulic conductivity of the soils were determined in the laboratory. During two selected time periods, irrigation water, was spiked with NaBr (5.0 mg/l Br). Bromide movement through the upper profile was quantified by soil water samples and post-sampling neutron activation analysis. Soil moisture was near saturatin in both soils when the Br tracer was applied. Bromide concentrations above background levels (0.023 mg/l Br, Doniphan silt loam and 0.016 mg/l Br, Crider silt loam) were detected within 2.60 hours at 0.9 m in the Doniphan soil and within 3.75 hours at that depth in the Crider soil. The rate of Br movement in the profile was greater in both soils than the measured saturated hydraulic conductivity, Bromide concentrations above background levels were present in soil water from the study plots for a minimum of 21 days after irrigation with the Br tracer.     

WATER QUALITY FROM TWO SMALL FORESTED WATERSHEDS IN SOUTHERN ILLINOIS1

Two intermittent streams on oak-hickory watersheds in southern Illinois were gaged with a V-notched weir and sampled with an automatic water sampler. For three years data were collected on flow volume and water quality. Flow volumes show large variations between years and watersheds. Samples were analyzed for Na⁺, K⁺, Ca⁺⁺, Mg⁺⁺, P, and NO^-₃. Water quality was consistently high, although there were significant differences between watersheds. A baseline for water quality has been established for comparison after one of the watersheds is clearcut at a later date.     

EFFECTS OF LAKE MICHIGAN DIVERSION ON THE WATER CHEMISTRY OF THE ILLINOIS WATERWAY1

: Chemical quality characteristics of the Illinois waterway covering a stretch of 270 river miles were monitored at approximately 10 mile intervals, during the period June to September of 1978 and 1979. A statistical method was used to define the interstation relationships for the chemical parameters. These mathematical models were used to predict the effects of Lake Michigan diversion. The mineral content of the mixed flow resulting from increased diversions are not likely to be altered drastically.     

GROUND WATER QUALITY IMPLICATIONS OF SOIL CONSERVATION MEASURES: AN ECONOMIC PERSPECTWE1

ABSTRACT: An evaluation of the intermedia movement of pesticides applied under various land management systems already in place, or to be implemented, under the Conservation Reserve and Conservation Compliance programs is presented. The simulation modeling approach followed in this analysis consists of a mathematical programming model and leaching/surface runoff, Pesticide Root Zone Model (PRZM) models. Special care was taken to ensure that the physical model was sensitive to the chemical characteristics of individual pesticides and the important physical changes brought about by different agricultural practices. Results show that, although these programs as now planned, increase farm income and achieve soil conservation goals, they may adversely affect ground water quality. Also, depending on soil and location characteristics, there are tradeoffs between surface and ground water quality implications. Hence, if these programs are to address water quality problems, the recommended practices must be evaluated for their impact on water quality, particularly in potentially vulnerable areas.     

PRICING IRRIGATION WATER IN DEVELOPING COUNTRIES1

ABSTRACT Alternative combinations of water pricing and regulations are possible in allocating irrigation water. The best combination will depend on the value of water, ability to control deliveries, desire to subsidize agriculture, ownership traditions, crops grown, return flows, drainage problems, staff training, ability to collect fees, the number of farmers involved, etc. Marginal cost pricing is just one possible alternative and it is more a way of thinking about prices rather than a set system. The possibilities for achieving an equitable and efficient distribution of water are improved if some form of marginal cost pricing is included in the system of water charges.     

REAL-TIME SOIL WATER MONITORING FOR OPTIMUM WATER MANAGEMENT1

Abstract: Efficient water resource management is one of the most important policy issues facing agriculture in Hawaii in the years ahead. Soil water sensors, multisensor capacitance probes (MCP), have been successfully used for different water management projects. These MCPs monitor water content at multiple depths and at various locations in real-time. The objectives of this study were to determine the effect of water content on field soil bulk density of Wahiawa silty clay tropical soil; measure field saturated hydraulic conductivity of this tropical soil: calibrate MCP system for this soil: and monitor and evaluate real-time soil water content variations under a tomato crop using the calibrated MCP system. Sensor calibration was conducted under laboratory conditions. Soil bulk density at different water contents and saturated hydraulic conductivity were measured on the field. Bulk density increased with increasing water content: there was a 30 percent bulk density increase as a result of 0.25 cm³ cm^-3 water content variation. Compared with the manufacturer's calibration, site specific laboratory calibration of MCP gave a more accurate determination of soil water. Field determined saturated hydraulic conductivity was higher than laboratory determined values reported in the literature for the same soil type. Real-time soil water content monitoring within the root zone showed substantial variations due to water input (irrigation and rainfall) and water output (evapotranspiration and deep percolations). However, water content variations were much further reduced in the soil layer below the root zone.     

CENTER PIVOT IRRIGATION IN THE COLUMBIA BASIN OF WASHINGTON AND OREGON: DYNAMICS AND IMPLICATIONS1

ABSTRACT: As of 1976 over 225,000 acres were being irrigated by center pivot units in a five-county area of the Columbia Basin in Oregon and Washington. Most of the development took place since 1970. Dynamic application of center pivot technology altered the concept of irrigability in the study area, converting lands that were often rolling, sandy, and plagued by wind erosion from low grade grazing to productive irrigated units. This development was entirely by private enterprise, with large corporate farms accounting for much of the effort. Little prior comprehensive planning or coordination took place. When the circulation of water is altered on such a massive scale, however, unplanned impacts may be far reaching. In this case they include:1) acceleration of the shift to high cost thermoelectric generation, 2) alteration of state institutions designed to allocate water, and 3) possible significant alterations of the socioeconomic fabric of small rural service centers.     

IMPROVING IRRIGATION WATER MANAGEMENT IN THE INDUS BASIN1

ABSTRACT: Over half of the water delivered from the canal system to the watercourses managed by the farmers is not made available to the farmers' crops in Pakistan. Most of this water loss is due to loss of water through the banks of the watercourses. Lack of maintaining these banks and lack of cleaning the watercourse is a result of inadequate organization of the 10 to 150 farmers who use the watercourse, and a deficiency of knowledge concerning the amount of their water which is being lost. Various methods of watercourse improvement have been evaluated including concrete and masonry linings and simple earthen improvements of the ditches with concrete control structures, junctions, and turnouts. With the cost of labor low in Pakistan, the earthen improvements with concrete structures appear to be the best investment. Farm water management improvement programs have been implemented in most of the provinces which include this type of watercourse improvement, land leveling and advice to the farmers on how and when to irrigate his crops to optimize his production. The rate at which personnel can be trained to help the farmers implement these improved water management practices is limiting the rate of implementation.     

THE IMPORTANCE OF SOIL IN EVALUATING POTENTIAL WASTE WATER DISPOSAL SITES IN THE MISSOURI OZARKS1

ABSTRACT: A number of criteria can be used in the selection of an area for the irrigation disposal of secondary treated waste water. The inherent capacity of the surface soil to retain, or at least detain, the various nutrient ions passing through the profile in the percolating waters becomes the prime consideration in regions with shallow water tables or in Karst areas such as the Missouri Ozarks where the risk of ground water supply contamination is high. A comprehensive study of the nutrient renovation potential of several soils was undertaken at a proposed effluent irrigation site along the Ozark National Scenic Riverways in south central Missouri. The surface soil hydrology was evaluated employing selected soil water parameters. Exchange equilibria studies determined the retention capacity for Ca and Mg while the concentrations of other selected ions were analyzed in the soil water to measure their retention time and net removal. The movement of a bromine tracer was monitored as an index of the renovation capacity of these soils for the more mobile anions such as nitrate. Neutron activation analysis proved to be a useful tool in the water quality analyses. All surface soil profiles demonstrated some degree of nutrient renovation for the various nutrients studied.     

TEMPORAL RESPONSES OF SURFACE‐WATER AND GROUND‐WATER TO PRECIPITATION IN ILLINOIS1

ABSTRACT: Illinois data from 168 months (1986–1999) were investigated to determine the responses of surface‐water and ground‐water resources to precipitation. Such responses were generally within the month of occurrence or one to two months later, with recovery being reached another one to three months into the future, depending on season of the year. Although the drought of 1988 immediately impacted surface‐water and ground‐water resources, the time of recovery was substantially longer compared to those of individual dry months, generally continuing for several months. The extremely wet summer of 1993 resulted in elevated responses in water resources almost immediately, but in this instance continued through the following fall and winter, into the spring of 1994.