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as Resolving Problems: Identifying and Evaluating Alternatives 1 The ultimate goal of the problem-solving process discussed in this re- port is to select and implement responses to help reduce or solve irrigation- induced water quality problems. The problem-solving process described is one that can be applied broadly to the nation's environmental problems. Regardless of the specific circumstances, however, one step in this pro- cess merits special emphasis: identifying and evaluating the full range of alternative solutions available. Chapter 4 outlined the generic systems approach necessary to assess any complex environmental problem and discussed the first steps of such a process. This chapter concentrates on the final steps- identifying and evaluating the range of responses available to decisionmakers. This committee has emphasized just how important it is for decision makers to display and debate openly the full range of available alternatives before filtering this broad group to a subset of most appropriate options. No potential option should be dismissed a priori, even if intuition judges it to be impractical or unpopular. In conceiving alternatives, there is a tendency to restrict the range of alternatives considered for two reasons: first, the people developing the list may have backgrounds that steer them to consider approaches within their expertise and leave them biased against "unconventional" solutions, and second, some obvious alternatives may be rejected a priori because they are assumed to be impractical, legally difficult, or politically unpopular. This tendency to prejudge or to fail to recognize" a number of alternatives must be overcome. As with problem definition, the judgment of a team 94
IDENTIl;YING AND EVALUATING ALTERNATIVES 95 of outside experts without vested interests can be useful in providing fresh insights and ideas. A few examples may illustrate the issue, even if their simplicity appears to overstate the point. The mission of the U.S. Bureau of Reclamation has been to develop water resources for irrigation. In searching for solutions to irrigation-induced problems, its personnel historically have not been likely to seriously consider reducing or eliminating the use of irrigation. Ocean disposal of irrigation drainage water, as another example, has been restrained by laws and regulation. Those accustomed to operating within the rules may not appreciate that laws can be changed; an academic scientist, on the other hand, is likely to see ocean disposal as a natural process, only accelerated by irrigation. This outside vision might recognize the value of assessing the costs, benefits, and disadvantages of various means of ocean disposal. Fish and wildlife specialists are accustomed to being last in line when it comes to water resource allocations. They may not appreciate that water for wildlife purposes might be provided at the upper end of an irrigation scheme, prior to use for irrigation, rather than at the lower end, after degradation. Thus, a wide range of alternatives structural and nonstructural, tech- nical and institutional-should all be displayed and openly debated. These also should consider shifts in priorities or shifts in the end use of the resource. Identifying and evaluating a full range of options should ensure that innovative ideas are not prematurely eliminated and that the true costs and benefits of each of the options can be assessed. To ignore certain options whatever the reasons for doing so- is to jeopardize the credibility of the overall analysis. Obviously, in the latter stages of any study the time and energy spent on the various options will begin to be weighted in favor of the more appropriate options (after all, this is the point of the study and evaluation process), but this should never preclude the importance of giving all options equal consideration in the early stages of an analysis. Using irrigation-induced water quality problems as a focus, the two sections below list selected classes of options to demonstrate the range that must be considered. One section discusses technical responses and the other discusses institutional responses, even though it is clear that successful strategies will need to combine elements from both categories. No attempt is made to be exhaustive or to advocate any particular option. Specific action packages from this range can only be chosen deliberately on a case-specific basis, and they must incorporate the essential elements of good problem solving described in Chapter 4.
96 IRRIGATION-INDUCED WATER QUALITY PROBLEMS TECHNICAL OPTIONS The irrigation of arid lands brings about major changes in land use and in the distribution and use of water. This in turn leads to a redistribution of salts, with unintended and sometimes unanticipated consequences. These impacts of redistribution often are minor initially, but they tend to become increasingly important over time. The primary and long-recognized adverse effect of irrigation is the generation of drainage water that carries substantial amounts of salts. The more acute and less common effect, vividly illustrated in the San Joaquin Valley, is the mobilization of specific trace elements in relatively small, but potentially toxic, concentrations. In evaluating drainage options, this distinction between types of problems must not be lost. A response that may be feasible for selenium removal may not be applicable for boron or nitrate removal. A treatment for a specific trace element may have no application for total salt load management. The redistribution of salts is a universal feature of irrigation in arid lands, and many of the problems associated with irrigation are due to excessive salt concentrations. Thus the long-term viability of irrigated agriculture becomes a matter of "salt management"-devising strategies to prevent salts from accumulating either in the irrigated area or downstream. The basic approaches available for this task include transporting the salts out of the system and storing salts where they will do no harm, leaving the salts in place, or treating the drainage water. Retiring problem lands from irrigated agriculture is an example of an approach directed at leaving salts in place. Deep-well injection is an example of storing salts, while building drainage canals to take the salts to the ocean is a means of exporting them. The following sections explore these classes of options in more detail. Through most of history, the most common approach to salt manage- ment on irrigated lands has been to discharge drainage water into streams. In the process, the often highly concentrated drainage waters are diluted by mixing with the river flow so that no adverse environmental effect is noted immediately. While this process has been used many times in many places, the cumulative effect can be severe, especially if it is combined with water diversions from the river. In fact, in principle, concentration is desired to reduce the cost of handling the waste stream and to reduce the volume of water dedicated to the disposal process. Transport and Disposal of Drainage Water The primary objective of draining irrigated lands is to remove excess water and salts in order to maintain a root environment suitable for crop
IDENTIFYING AND EVALUATING ALTERNATIVES 97 growth. However, once the drainage water has been collected, the salts must be transported and disposed of in some acceptable manner-by dilution or by storage in a location where they will cause little damage. Treatment of the drainage water may also be necessary to facilitate either transport or disposal. Ocean Disposal One direct way to dispose of drainage water is to discharge it to the ocean. The challenge is to avoid adverse effects in transit. In some cases, salts in the discharged water can be sufficiently diluted with other water so they do not create a water quality problem during transport. This traditional approach has often been carried out by constructing drainage canals to carry drainage water either back to a river with enough dilution water in it, or directly to the ocean. If the salts do not ultimately reach the ocean, however, the water quality problem is only being postponed or moved elsewhere. For instance, the disposal of the return flows from the New Lands Project into the Mucked River in Nevada has only served to cause severe water quality problems in the Stillwater basin. Studies assessing disposal of the San Joaquin Valley's drainage water by discharging it into San Francisco Bay or directly into the ocean have shown these options to be expensive and controversial. As indicated in Chapter 1, the San Luis Drain originally was to extend to the bay, but its high construction cost and public opposition resulted in its being terminated in the ponds at Kesterson National Wildlife Refuge (NWR). Although the planners had hoped that additional funds would be allocated to complete the drain, such a solution is probably no longer socially or politically acceptable because of concerns over possible adverse impacts on water quality at the point of discharge. Another ocean disposal option would be to transport the San Joaquin Valley's drainage water directly to the ocean through closed conduits con- structed over the Coast Range. This approach would be expensive and also has generated substantial opposition. Eking the analysis beyond the example in the San Joaquin Valley, it must be recognized that ocean disposal generally involves transporting drainage water in natural channels (e.g., the Colorado River). The question to be answered regardless of site is whether a management plan can be devised that avoids or reduces adverse effects associated with transport and discharge. Deep-Well Injection Another technology undergoing study is deep-well injection, when excess salts are disposed of by injecting them into abandoned deep wells
98 IRRIGATION-INDUCED WATER QUALITY PROBLEMS (Lee et al., 1988b). Deep-well injection has long been used by the oil and gas industry to dispose of oil field brines. The application of this technology for agricultural drainage water is a relatively recent modification, however, and it faces a variety of technical, financial, and institutional constraints. For instance, because of the great volume of drainage involved, it may not be feasible to inject the entire return flow, requiring first that the drainage be treated to reduce the volume and as a consequence concentrate the salts. This would be an expensive undertaking. If the entire return flow were injected, substantial amounts of water would be removed from possible use by downstream residents or to support in-stream flows. Furthermore, it is difficult to establish with certainty that the injected water will not have long-term negative effects on regional water quality. Also, there is some concern that large volumes of injected water could destabilize the region tectonically. Source Control Source control can be described as those salt management activities that are undertaken at the farm level, the source of the drainage water. Salt management approaches that rely on source control essentially rely on leaving the salts on the land. Retirement of Land from Irrigated Agriculture One way to manage salt loads is to retire the most problematic lands from irrigated agriculture. Land retirement eliminates the need for salt and water disposal on those lands retired. As a result of reducing the number of acres irrigated, the rate of export of salts offsite through ground water and surface runoff also is reduced. Alternate land uses chosen for the retired acreage must be assessed to ensure that water use and drainage volumes would be reduced. Managen~ent of Iwigai'on Another approach to managing salts at their source is through irrigation management. The quantity and quality of irrigation drainage water can be affected significantly by increasing the efficiency of irrigation by better management of existing systems or by introducing more advanced irrigation technology (van Schilfgaarde et al., 1974~. One example of a technologically advanced system enabling precise control of water application is subsurface trickle irrigation with automatic feedback control for determining the timing and amount of water application. Such systems are designed to reduce drainage while increasing water use efficiency and crop yield, but at a relatively high cost of capital investment and management skills (Phene et
IDENTIFYING AND EVALUATING ALTERNATIVES _..... . ~.~. ~ ,',: ~-4 L. . 99 _ 3~ _ :: I One technical approach for managing salts at their source is through improved irrigation management. Drip irrigation, used here on furrowed cotton in California, conserves water and energy and reduces the threat of erosion. Such systems can reduce drainage but are expensive and require increased management skills. Inset: close-up of an "in-line" emitter. CREDIT: Soil Conservation Service, T. McCabe. al., 1988~. Such techniques can reduce drainage volumes well below 10 percent of the amount of irrigation water applied. One approach is to recycle drainage water and use it directly, perhaps diluted and supplemented with additional irrigation water, to grow salt- tolerant crops. Rhoades et al. (1988) demonstrated that as much as 50 percent of the water used to irrigate crop rotations that included cotton, alfalfa, melons, and sugar beets could be supplied from a drainage source containing over 3000 mg~l total dissolved solids. This option, however, may simply transfer increasing salinity problems to smites downstream. Irrigation management alone will not provide a long-term solution to salt management but can delay the onset of a problem until other approaches become more feasible. It can retard the rate of salt discharge in the drainage water and, at a steady state, often reduce the total mass of salts discharged. In addition, irrigation management simultaneously reduces the amount of drainage water that ultimately needs to be removed. Unlike land retirement, irrigation management allows agricultural production to continue. However, source control activities generally require more careful
100 IRRIGATION-INDUCED WATER QUALITY PROBLEAdS Throughout history, the main challenge for irrigated agriculture has been salt management. Evaporation ponds are a commonly used means to deal with saline subsurface drainage water, but the potential for adverse environmental impacts is significant. The light-colored areas in cropped fields are due to high soil salinities resulting from poor drainage. CREDIT: Jim Oster, University of California, Riverside. management than is necessary with more traditional irrigation techniques, and they result in higher salt concentrations in the drainage water. Onsite Evaporation Ponds The major mechanism available to concentrate salts is evaporation, a process seen throughout the arid West in naturally formed salt lakes and dry salt beds. The construction of onsite evaporation ponds to collect and concentrate salts from irrigation water drainage is an attempt to use this natural process to store salts temporarily or permanently at a selected location. Evaporation ponds are a commonly used means to deal with saline subsurface agricultural drainage water (Lee et al., 1988a). Although many drainage dischargers view ponds as a viable means of disposal, the potential for adverse environmental impacts is significant. One disadvantage of evaporation ponds is that the area devoted to the ponds is removed from agricultural production or other uses for the
IDENTIFYING AND EVALUATING ALTERNATIVES 101 foreseeable future. Typically, 15 percent of the land area farmed must be sacrificed to the pond (Tanji et al., 1985~. Another is that evaporation ponds remove water from the system and thus reduce the amount available to downstream users and for in-stream How. Evaporation ponds can be biologically productive and attractive to waterfowl. The biological productivity can be expected to decrease, how- ever, as the salt concentration increases. Also, unless specific measures are taken to prevent the seepage of saline waters into ground water, evap- oration ponds also can contaminate local ground water. However, after evaporation ponds have been in use for some time, the ponds tend to seal, substantially reducing saline water intrusion into the ground water. The presence in the drainage water of trace elements, even in relatively small quantities, changes the situation drastically. Concentration through evaporation can lead, in short order, to levels that are toxic to fish and fowl. In fact, in the San Joaquin Valley, excessive levels of arsenic, boron, molybdenum, and selenium have been noted in some evaporation ponds (Schroeder et al., 1988~. Such ponds are no longer just evaporation ponds, but need to be considered as potentially hazardous waste disposal sites, subjecting them to stringent regulations. Extensive studies of both the biological and chemical characteristics of evaporation ponds where trace elements are a problem have led to design recommendations intended to reduce the ponds' use by biota. Mul- ticell ponds with a minimum water depth of 1 m, with steep sides, and with banks and levees cleared of vegetation will reduce use by waterfowl, shore birds, and macroinvertebrates. Aquatic plants can be controlled with herbicides, and other pesticides may be needed to control invertebrate populations (Parker and Knight, 19894. In short, this presumably simple solution to a waste disposal problem can readily grow into an expensive and environmentally hazardous endeavor that may no longer be called a solution. Thus onsite evaporation ponds can offer only an interim service that can be useful while other, permanent solutions are sought. They will also, however, create a neat range of problems in the long run. Drainage Water Treatment Technologies Scientists and engineers have developed a number of water treatment technologies that might be applied to irrigation-related problems. Some are applicable to specific substance removal; others remove all salts. These technologies are, in general, an expensive approach to salt management. They also add the problem of disposal of the removed salts.
102 Desalinization Technologies / IRRIGATION-INDUCED WATER QUALITY PROBLEMS Desalinization technologies usually are used to create high-quality water, usable for drinking or other purposes, from a saline source. The primary technologies used in desalinization are reverse osmosis and flash evaporation. Both are capital and energy intensive, and thus the cost of separating the salt from the water tends to be high. A desalinization plant is being built near Yuma, Arizona, to remove salts from the Wellton- Mohawk Irrigation and Drainage District before the drainage water is released to the Colorado River. However, analyses show that this is a very expensive option (van Schilfgaarde, 1982~. The use of such technologies also creates the problem of disposing of the highly concentrated salt-rich waste. Thus these technologies only provide ways of concentrating the mixture to be disposed of; they are not a solution to the problem itself. Desalinization plants need to be part of an integrated strategy for residual salts management. Chemical and Biological Removal Chemical and biological approaches can also be used to address some salt management issues. In the San Joaquin Valley, for instance, high concentrations of selenium are of special concern; Studies have shown that ferrous ions or iron filings can be used to create selenium-rich sludges that can be separated from the drainage water (Lee et al., 1988a; Murphy, 1988~. However, even if one of these processes were perfected and made economically attractive, it would still leave two problems. First, the total salt concentration would not be affected and the need would remain to dispose of the selenium sludge. Second, these approaches are specific to selenium and do not address the wider question of other trace elements. One biological approach investigated in the San Joaquin Valley uses fungi to remove selenium. Certain fungi, when provided with a source of energy and maintained in a favorable (anaerobic) environment, will metabolically convert selenium compounds to volatile dimethyl selenide (Lee et al., 1988a). This process shows potential to remove selenium from contaminated soils (Frankenberger and Karlson, 1988~. Again, however, this approach is selenium specific. Another proposed biological approach that deals specifically with sele- nium involves using organisms that facilitate selenium accumulation in biota without causing toxic responses (Lee et al., 1988a). In small pilot projects, bacterial filters have demonstrated some success, but the feasibility of this approach at a large scale is uncertain, and it is doubtful that the technology can be worked out in the short time frame necessary for remediation. The biologically oriented technologies that show some promise have
IDENTIFYING AND EVALUATING ALTERNATIVES 103 not advanced past the research or pilot stage. If found to be feasible, they would need to be evaluated as part of an overall management strategy. INSTITUTIONAL OPTIONS Finding a solution to the complicated water quality problems caused by irrigation requires a careful review of institutional as well as technical options. Although the two options are addressed separately in this chapter, they cannot be dealt with separately in actual practice. As was discussed in Chapter 3, the social and scientific aspects of a problem are inextricably intertwined. In many cases, an institutional option would be used to bring about the use of a preferred technical option. Ultimately, the finest technical option is of little value if there is no institutional way of assuring its implementation and continuing operation. Situations exist where institutional change alone might bring about desired improvements. Even if no specific technical option is preferred, adopting certain institutional changes can encourage irrigators to adopt one or more of several beneficial options. The choice is left to the individual decisionmaker, depending on the particular circumstances. The strategies ultimately chosen to cope with irrigation-related prob- lems will undoubtedly involve a mix of various institutional options. This section discusses four types of institutional options: price adjustments, legal changes, organizational changes, and political and social changes. Price Adjustments Chapter 3 discussed the various economic factors that contribute to the water quality problems associated with irrigation drainage water. Many of these problems occur because the prices irrigators pay for their resources or receive for their products do not reflect actual social costs. Thus one way to correct these discrepancies is to adjust the relevant prices. Accurate Market Prices The most obvious discrepancy is in the price that irrigators pay for irrigation water. Adjusting the price of water so that irrigators pay the full cost of providing it would make those farmers served by government irrigation facilities operate more efficiently. In situations where irrigation proved to be an uneconomic operation, it would reduce the amount of irrigated acreage. Irrigators would tend to use less water, thus leaving more to serve other social purposes. Even a relatively small reduction in demand would free significant water supplies for other uses because of the substantial amount of water consumed by irrigated agriculture in western states.
104 IRRIGATION-INDUCED WATER QUALITY PROBLEMS Similarly, removing price supports for surplus crops would induce irrigators to grow fewer of these products, again resulting in an increase in efficiency and a reduction in government price support payments. However, such changes, as much as they might improve the system's general efficiency, are unlikely to correct drainage problems fully. They might reduce the amount of drainage generated, but they would not neces- sarily reduce it in those areas causing the most serious problems. Making such major price changes could also significantly worsen the financial condi- tion of many farmers and cause other unwanted social repercussions. Many of the people affected would not be causing downstream water quality prob- lems. Others would find it more difficult to invest in alternative actions to reduce drainage problems. Finally, as simple as such price adjustments appear in theory, they would be difficult to implement. Many irrigators ob- tain their water under long-term contracts in which the prices already have been established. For irrigators who provide their own irrigation supplies, the only way to adjust the cost of water is for the state to charge for the right to use water. Although such charges are not unknown, they would represent a radical change and would be hotly resisted. Similar implementation problems affect proposals to remove price sup- ports from irrigated crops. There would be no effective way to implement such a policy unless the supports were eliminated for all farmers. Nor would such a change necessarily have a significant impact on irrigation drainage problems. Truces and Charges One way to adjust costs in a manner more closely focused on drainage problems is to impose taxes or charges on the irrigators responsible for these problems to pay the costs of ameliorating the damages. Special drainage taxes could be instituted for problem lands or inputs such as water, fertilizers, or pesticides in problem areas. Economic theory suggests that increasing the eRective price of these inputs would induce some farmers to conserve them. Practical problems arise, however. It may not be legal or possible to focus taxes on inputs used only in specific drainage problem areas. Furthermore, input taxes are not necessarily an efficient approach to solving environmental problems caused by output (e.g., drainage). However, this approach has the benefit of providing a source of revenue that could be used to fund mitigation programs. Alternatively, irrigators could be charged on the basis of the amount of drainage they generate or the amount of contamination in that drainage. Such charges (or effluent fees) might act to induce irrigators to take actions
IDENTIT;'YING AND EVALUATING ALTERNATIVES 105 to reduce the volume of drainage or the quantity of harmful constituents in the drainage. Charges on outputs also provide the advantage of generating revenue. Again, however, this approach would be difficult to implement, particularly in irrigated areas where drainage is difficult to measure because it occurs underground in natural channels rather than in constructed networks. Subsidies Another way to adjust prices is to subsidize those investments or other purchases that the government wants to encourage. Such subsidy programs are particularly common in the agricultural sector. The government often shares in the cost of soil and water conservation measures on private farms or provides free services such as education and extension. In other sectors, tax benefits and tax-free bonds may be more common types of subsidies. Subsidies have the advantage that they can be focused on the most serious problem areas. Subsidized technical assistance, for instance, can be focused on the farms thought to be creating the most serious problems. Extension agents can work directly with farmers to identify the most effec- tive means of eliminating problems at a given site. If a proposed solution involved some investment (e.g., the installation of a more efficient irrigation system), the government might also share in its cost. Cost-sharing is gen- erally more difficult, although not impossible, when the response involves improved management practices. The major difficulty with subsidies is that they require increased gov- ernment expenditures for a sector that is already heavily subsidized. Adding additional subsidies may only increase overall inefficiencies. Furthermore, the subsidies typically are available only for certain types of activities, and these are not always the most effective or efficient solutions. It is possible, however, to use subsidies in conjunction with regulatory procedures. The Food Security Act of 1985 introduced the principle of cross-compliance: farmers' eligibility for various support payments was made contingent on their adoption of conservation practices. Similar cross- linkages between good management practices or drainage reduction on the one side, and subsidized water prices or crop price supports on the other, may offer an opportunity for persuasion without excessive unilateral controls. Legal Changes Existing legal provisions strongly influence the feasibility of selecting various technical solutions to reduce the water quality problems associated with irrigation drainage water. In some cases, modifying these provisions to remove certain constraints could help in the implementation of desired
106 IRRIGATION-INDUCED WATER QUALITY PROBLEMS solutions. However, it is also possible that new laws may have to be enacted to authorize a preferred approach. Constraints on Water Transfers Both state and federal laws and procedures significantly affect the economic benefits and costs associated with market transfers of water rights (Colby, 1988~. Some improvements in the efficiency of irrigation systems could be accomplished by addressing these legal constraints. Perhaps the most important of these would be modifying~existing provisions for selling water rights. Although they vary from state to state, existing provisions often provide no incentive for irrigators to use water more efficiently because they are unable to sell the water that is conserved. State policies that allowed conserved water to be applied to new land and new uses and that allowed conserved water to be leased or sold would reward conservation efforts and could reduce disincentives for water conservation generated by forfeiture and abandonment laws (Saliba and Bush, 1987~. At this time, laws in the western states vary considerably. In Arizona, while no specific statutes regulate the transfer of conserved water, case law seems to preclude transfers to lands other than those to which the water right was originally assigned. California, on the other hand, specifically provides that conserved water may be sold, leased, or otherwise transferred. Nevada law takes the position that "since beneficial use is the limit and extent of a right, a water user has no right to his inefficiencies." Thus conserved water is considered unappropriated and any applicant may file to appropriate it (Saliba and Bush, 1987~. As was discussed in Chapter 3, the question of who actually owns the rights can also be complicated. In some cases it is the irrigator, in some cases the irrigation district, and in some cases the U.S. Bureau of Reclamation (USER); in some cases ownership may not be clear. Even if state law supports efficient water transfers, federal authorizing statutes or the USBR's administrative procedures may inhibit such an approach. Reducing the constraints on water transfers would not, by itself, neces- sarily reduce the water quality problems associated with irrigation drainage. In a manner similar to increasing water prices, it could lead to a general improvement in the efficiency with which water is used, but these im- provements would not necessarily be focused on areas creating the most serious water quality problems. However, if the preferred technical so- lution involves improved water management or taking certain lands out of production, easing the irrigator's ability to sell the water saved could significantly encourage implementation.
IDENTIFYING AND EVALUATING ALTERNATIVES 107 Constraints on Drainage Existing water law also could be modified to make it pertain to the quality of the drainage water as well as to the quantity withdrawn and consumed by irrigators. At the federal level, abolishing the section of the Clean Water Act that exempts irrigation return flows from the pollution control provisions governing other dischargers might be the most direct approach. Similar changes could be made in state water quality laws. Such changes, however, would retain the existing separation between the legal structure governing water quantity and that governing water quality. Incorporating water quality concerns directly into the legal structure governing the allocation of water would probably require states to modify their existing legislative doctrines. Conceivably, the reasonable use doctrine could be expanded to include a water quality dimension, for instance by declaring that reasonable use requires that any unused water or waste water be of sufficiently good quality that it causes no damage to downstream users or to the environment. Such a concept is at least implicitly incorporated in the riparian doctrine of water use but historically has had little influence on the quality of water discharges in areas where that doctrine prevails. Another approach might be to expand the concepts incorporated in the public trust doctrine to include water quality concerns. This doctrine was used by the California Supreme Court to control the amount of water that Los Angeles could remove from the Mono Lake basin because of the impacts these withdrawals were having on the water quality in Mono Lake and on the viability of the ecosystem. This doctrine, however, is not clearly defined, and how it might be applied to any particular circumstance is very uncertain. Regulatory Approaches The most direct legal approach would be to adopt new regulatory pro- grams that would require the implementation of desired technical solutions in those areas causing significant water quality problems. These programs could control any or all stages of the irrigation and farming process: the use of inputs, irrigation management, or the quality of the drainage. Controls on inputs could limit which lands are irrigated, restrict the amount of irrigation water applied to the land, or restrain the types or quantities of agricultural chemicals used (if these are the cause of the water quality problem). However, controls on inputs may not solve the problems and are likely to be inefficient. One method proposed to control agricultural use would be to define soils containing trace elements in problem-causing quantities as "geologic hazard areas" and restrict agricultural use that would cause leaching and deep percolation. This could be legally similar to existing floodplain management strategies.
108 IRRIGATION-INDUCED WATER QUALITY PROBLEMS Controls on irrigation management could include any of the techniques described previously in the "Technical Options" section of this chapter. Again, adopting such a regulatory approach implies that the regulator knows how to solve the problem as well as or better than the individual farmer. In some cases, it can be difficult to enforce this type of approach because of the difficulty of determining whether the farmer is in fact using the required management practice. Controls on the quality of the drainage water or on the ambient quality of the receiving water focus most directly on the problem of concern and allow the irrigator the most flexibility in choosing how to solve the problem. However, enforcing such an approach can be a problem because of the difficulty and cost of monitoring drainage flows., Controls on ambient quality also raise questions about allocating responsibility for the problem among the various dischargers. One possibility might involve raising the level of control from the individual irrigator to the water district. This could reduce the need for intensive monitoring and quantitative source determination at the farm level by passing the responsibility of allocation to the members of the district. This issue is addressed further in the section "Organizational Changes" in a somewhat different context. Organizational Changes Implementing effective and efficient solutions to the problems being experienced in the San Joaquin Valley may require modifications in certain administrative organizations because of the conflicting responsibilities of the different agencies and institutions involved in water management. Broadening and Redefining Responsibilities One way to reduce the institutional problems caused by conflicting responsibilities would be to broaden the responsibilities of existing institu- tions. For instance, water supply institutions such as the USER and the water (and irrigation) districts could be made responsible for the quality of drainage water as well as the provision of water for irrigation. Alter- natively, water pollution control agencies could be given responsibility for supplying water as well as controlling the amount of pollution in water discharges. The geographic jurisdiction would have to be defined along hydrologic boundaries rather than political ones. If a major effort were made to broaden some agency responsibilities, some conflicts and confusion would likely result because several different agencies could then have responsibility for dealing with the same problem. Thus there would need to be a concurrent redefining and consolidating
IDENTIFYING AND EVALUATING ALTERNATIVES 109 of agency responsibilities. These changes would probably be very diffi- cult to implement. They might, however, help significantly to prevent future problems such as the contamination of Kesterson NWR. They also might improve the nation's capability to respond to those problems that have already occurred if they ultimately helped improve coordination and communication among the nation's water resource and water management agencies. Correcting Other Insi~tutzonal Impediments In the process of attempting to deal with the problems at Kesterson NWR and similar sites throughout the West, numerous other institutional constraints will undoubtedly be discovered. Problems involving the length of irrigation contracts and the question of who actually owns water rights have already been mentioned. Another institutional impediment in some parts of the San Joaquin Valley is that water often is delivered to irrigation districts and individual farmers on a fixed schedule, regardless of whether it is needed. This can result in the farmer applying excess water to the land, thus causing increased drainage. Such a system also precludes the farmer from adopting efficient irrigation systems that apply low volumes of water on an almost continuous basis. A water delivery system set up to make water available when it is needed would reduce these problems and would probably increase production and improve water use efficiency. Such a change, however, would require investments to increase the capacity of water supply systems and to provide nearby storage facilities. The types of changes needed to resolve such institutional constraints will depend on the technical solutions that are selected. For some techno- logical choices, institutional constraints may be very important; for others, the significance may be less. Finally, the search for the best solution must recognize that different agencies and institutions are governed by different legal standards and follow different administrative procedures. Some of these standards and procedures may be too ponderous to allow an agency to respond effec- tively to the problems associated with irrigation drainage water. Thus the institutional procedures governing the institution itself can constitute an important consideration when an institutional response is selected. Political and Social Changes No technical or institutional solution, no matter how elegant, is likely to be implemented successfully if it does not have adequate political and social support from all sides of the controversy. This is one reason why the entire process of identifying and evaluating alternative solutions should
110 IRRIGATION-INDUCED WATER QUALITY PROBLEMS be open and should involve substantial public participation. Active efforts need to be made to build support for the desired changes in the state and federal legislatures as well. One primary consideration in developing social and political support for a proposed solution is how the costs and benefits are distributed among the affected populations. If this distribution is seen as inequitable, significant opposition can develop. Finding the "right" balance can be one of the trickiest parts of deciding on a solution. If it offers powerful political interests too few benefits, or if they are expected to pay what they perceive as an undue portion of the costs, they may be able to block a proposed solution politically. However, significant opposition also can result if less powerful interests such as small farmers or minorities are unfairly affected, or if the general taxpayer is expected to pay a major portion of the bill for investments that will benefit a small group of already heavily subsidized irrigators. EVALUATING ALTERNATIVES The final step in the study process is to evaluate the technical and institutional options that have been identified and select those that appear to be most attractive. Although this is the final step in the study process, the criteria and procedures that will be used need to be clearly thought out and made explicit at the beginning of the study. If this is not done, the prior steps may not provide the information necessary to conduct solid evaluations, and the evaluations and ultimate decision may be considered suspect. Thus much of the planning for the evaluation phase should be con- ducted early in the study, most appropriately at the time that the problem is being defined. Like the problem-definition process, this planning should incorporate substantial public input and discussion. All segments of the public need to have confidence that the decision-making process is legit- imate and that it will reflect their values. Making an effort to build this confidence at the beginning of the process should help the entire study proceed more efficiently and should result in the final recommendations being broadly supported. It is an investment that is usually very profitable, but all too rarely made. Thus the committee cannot overemphasize the importance of defining the problem clearly and comprehensively. How the problem is defined- whether explicitly or implicitly-will determine what solutions are explored and implemented. Obtainable goals can be set only if the problem to be solved is clear and agreed upon by all parties. All responses have different impacts on the affected interest groups. A response at the local level may aggravate the problem at the state or national level. The simplest
IDENTIFYING AND EVALUATING ALTERNATIVES 111 engineering response may be an environmental mistake. A quick fix may preclude a future, permanent cure. The benefits of each alternative for all affected parties must be carefully assessed, and decisionmakers must remember that all responses have costs money, resources, energy, and social costs. Who will pay becomes an essential consideration, and, like the other questions raised, the answer depends very much on the perspective from which the question is asked. It may be that no answers are possible in which all the parties win, so that compromise is more often than not the only realistic goal. Evaluation Criteria The principal evaluation criterion is, of course, the extent to which the proposed option will help solve the problem the study is addressing. Again, this emphasizes the importance of defining the problem accurately and early. The link between problem definition and the ultimate choice of options can be solidified by including in the definition explicit mea- sures for determining how success will be measured. For instance, if the problem is defined to be deteriorating water quality, the definition of the problem should indicate which particular contaminants are of concern (e.g., selenium alone, other specific salts, all salts, all agricultural chemicals, all contaminants for which water quality standards are in place, or some other specific list of substances). The definition should also indicate whether im- provement would be measured by the average concentration of pollutants in the receiving water, the maximum concentration of pollutants in the receiving water, or some other criterion. Success in solving the defined problem is not, however, the only crite- rion for evaluating alternative options. Various other technical, economic, institutional, and environmental criteria must also be considered. In the water resources field, substantial effort has been spent over the past 40 years developing criteria and procedures for project evaluation. These were first compiled and published in the Federal Register in 1973 (Water Resources Council, 1973~. This landmark discussion of principles and standards set forth four "accounts" national economic development, environmental quality, social well-being, and regional development that are to be evaluated when analyzing the advantages and disadvantages of proposed water resources projects supported by any federal agency. An update published in 1983 provides additional principles and guidelines (Wa- ter Resources Council, 19834. The regulations implementing the National Environmental Policy Act's requirement that environmental impact state- ments be prepared for such projects, and Executive Order 12291, which requires that cost benefit analyses be conducted for many federal activities,
112 IRRIGATION-INDUCED WATER QUALITY PROBLEMS also influence the structure and content of evaluation processes carried out for federal actions. Regardless of the particular requirements or emphases of these specific evaluation procedures, any comprehensive evaluation should consider four general categories of criteria-technical, environmental, economic, and other institutional. Again, the way in which these evaluations will be conducted and the specific criteria and measurements that will be used in the evaluation process should be spelled out early in the study process. Technical Criteria Any proposed response to an irrigation-induced water quality problem needs to be technically and scientifically sound. Where the technology has been proven and widely demonstrated to be effective in real applications, the primary concern is whether there is anything different about the pro- posed application that might disrupt the technology. For new technologies, however, the evaluation will need to consider whether the technology acts in concert with scientific principles, whether it is consistent with existing engineering practice, whether it is likely to have any adverse side effects, and whether there are any characteristics of the proposed application that might interfere with its functioning properly. Any technology ought also to be evaluated on the basis of whether it truly resolves or only changes the problem, and whether the solution is long term or short term. A technical approach that simply removes the salt from the drainage water (e.g., using a membrane desalinization process) has a disadvantage; although it may remove the contaminants from the water, it creates another waste stream of high salt concentration that still requires disposal. Some solutions, such as the original proposal to use Kesterson NWR to evaporate irrigation drainage water, may work in the short term but be ineffective or even create more serious problems in the long term. Environmental Criteria Although the environmental and ecological viability of proposed ac- tivities often was not given significant consideration in the past, this has now become a primary concern. At the least, the proposed action should have little adverse impact on the stability and functioning of existing nat- ural ecosystems. Beyond being environmentally nondamaging, however, responses that help restore degraded ecosystems and increase the provision of environmental amenities are generally to be preferred over those that do not. Evaluating the absence of negative impacts and the provision of en- vironmental benefits needs to be closely tied to the technical analysis and evaluation of the option. Otherwise the technical analysis may miss some
IDEN1:~IFYING AND EVALUATING ALTERNATIVES 113 potentially significant impacts, and the project design may miss some im- portant opportunities to generate environmental benefits. The environmental evaluation is often difficult for two reasons. One is the often substantial uncertainty involved in efforts to assess and predict environmental effects. The second is the problem of developing good, unambiguous measures of these effects. Economic Criteria The third set of criteria relate to the economics of the proposal. Economic efficiency is usually a major consideration. Is the proposal cost-effective that is, does it represent the least-cost way of achieving the benefits it provides? How efficient is it that is, by how much do the expected benefits exceed the expected costs? These are the standard questions regarding the proposal's economic efficiency. But economic efficiency is only one aspect of the economic evaluation. A second is the financial question is the proposal affordable? Particularly in times of tight government budgets, very expensive projects are unlikely to be funded even though they appear to be very efficient. No matter how efficient a proposal may appear in theory, the concept has little meaning if the project is never implemented. Another important economic consideration is how the benefits and costs of the proposal are likely to be distributed. Who will end up paying for, and who will end up receiving, the benefits? Is this distribution equitable? Is there any way of getting the beneficiaries to pay more of the costs? This distribution question will be closely tied to the financial question of how the proposal will be funded. Other Institui'onal Criteria All proposed alternative responses also must be evaluated in light of various other institutional criteria such as social and political acceptability, whether the responses are in accord with existing laws and court interpre- tations, and whether they fit into existing institutional responsibilities. The more congruent the proposal is with existing practices, the more likely it is to rate well according to these criteria. On the other hand, however, environmental problems are often caused by existing practices; when that is the case, any effective solution will have to change those practices. The questions then become how much the practices have to be changed, how difficult these changes will be, and what incentives can be created to encourage them. The fundamental question in this part of the evaluation is whether the proposal can actually be implemented. The most effective and efficient approach is of little value if it cannot (or will not) actually be put in place.
114 IRRIGATION-INDUCED WATER QUALITY PROBLEMS In this case, the evaluation phase may involve significant effort to develop effective implementation strategies. An assessment of the likely success of these options should then be fed back into the technical, environmental, and economic evaluations to develop improved estimates of how well the proposal will in fact address the problem. Clearly there are very few ways of quantitatively measuring these institutional criteria. That fact, however, does not diminish the importance of their evaluation. The Evaluation Process Evaluation the analysis and interpretation of data-is required for understanding. Careful thought is necessary to turn data into informa- tion. The interpretive activities that facilitate the conversion of data into information are seldom given sufficient attention in study design. Programs of the magnitude required to solve environmental problems must establish a specific plan to evaluate and interpret the data. Re- searchers should not expect that some obvious answer will emerge on its own or that the measurements acquired by the individual disciplinary team members will be integrated for effective interdisciplinary problem solving without pointed efforts. Serious effort is necessary to transform data into relevant information. Although the evaluation process is the last to be completed, it should not wait until all the other study elements are accomplished. Instead, the evaluation process should be ongoing. Nor should every proposed response necessarily receive the same thorough analysis. Relatively simple evaluations conducted early in the study may demonstrate that some options are clearly undesirable, for instance because they are technically infeasible or prohibitively expensive. Thus the evaluation process may be a series of evaluation filters, with increasingly rigorous analyses being conducted as the study progresses. Another reason for beginning these analyses early is that they may demonstrate that some important questions are not being asked or necessary information is not being collected. Thus there should be feedback from the evaluation phase to the information-collection phase. The feedback can also occur in the opposite direction if information- collected in other phases of the study indicates a need for modifying evaluation criteria for instance, by adding additional contaminants or considering additional environmental effects. The process of investigation, analysis, and evaluation of alternatives is dynamic. Judgment must be exercised in a process that weighs criteria, con- straints, and opportunities and that uses comprehensive, interdisciplinary analysis to generate a variety of possible appropriate responses.
IDENTIFYING AND EVALUATING ALTERNATIVES 115 ~ determine the appropriate responses, decisionmakers should as- sess how the various actions respond to the goals articulated early in the problem-solving endeavor. In most cases, a combination of approaches will be necessary. Four sources of input need to be weighed in the decision-making process, including: 1. technical input and scientific standards; 2. legal mandates and administrative guidelines; 3. political input; and 4. public desires (which sometimes can differ dramatically from polit- ical input). In the past, professionals with relevant technical expertise tended to make most resource management decisions. Over time, however, the U.S. legal system has evolved to provide broader guidance, and the public has become increasingly involved. Also, it was assumed in the past that the public view was represented by the political input, but that perception has now become more realistic. The identification and evaluation process must consider questions such as the following: Does the option involve proven technology? What are the costs, and what are the benefits? Who pays, and who benefits? · How difficult is it to implement the option? · What is the time frame is the option a temporary or a permanent solution? What emerges from a constructive consideration of these questions will not be one "right" solution but rather a combination of institutional initiatives and technical measures. In the process of formulating this mix, trade-offs associated with different options will become evident. Legal or political constraints will emerge that might interfere with the implementa- tion of some options that may appear technically attractive. The final decision will involve a difficult process of weighing competing and conflicting demands and developing procedures to alleviate or manage the conflicts. ~ade-offs must be recognized and compromises negotiated. Each stage in a problem-solving endeavor should involve some effort to consider equity questions-basically, who pays and who benefits. An effec- tive solution cannot be implemented without weighing the trade-offs that are inherent in any judgments and choices. Resolving disputes early in the process reduces the probability that the courts will need to play a role later in the process. In the end, the ultimate decision on what actions to
116 IRRIGATION-INDUCED WATER QUALITY PROBLEMS take to reach the stated goals will be a compromise blending technical and institutional components. CONCLUSIONS Chapter 4 introduced five basic functions that characterize problem solving: (1) recognizing a problem, (2) defining the problem, (3) assessing the data base and collecting data, (4) identifying alternative responses, and (5) evaluating those responses. Although these discussions have focused on independent system components, the importance of an interdisciplinary approach cannot be overemphasized. The ultimate task in problem solving is to evaluate the information gained for each component in relation to the others and to integrate that information for interpretation. Thus the final function to consider in any problem-solving endeavor is how to use an iterative process incorporating these basic steps. As data are gathered and evaluation proceeds, a series of possible responses will evolve some with less certain outcomes than others. While some types of uncertainty can be dealt with explicitly and quantitatively through good quality control, other types of uncertainty can only be han- dled through the adoption of compromise. The goal of using an iterative problem-solving process is to provide feedback for midcourse corrections, so that control can be exercised even when the events cannot be predicted. In the management of natural resources, the ecosystem processes that are being managed occur on time scales longer than the design of most experiments. The areas being managed typically are large. It follows, therefore, that knowledge from experimental science at these scales is likely to be sparse. Monitoring can be thought of as the straightforward data- collection phase of long-term, large-scale experiments. Monitoring plays a crucial role in evaluating and assessing the success (or lack of success) of management in meeting stated goals. Because a system's response to management at these scales is not likely to be perfectly predictable, and because, as a system changes in response to management, predictability may be even less certain, it may be necessary to alter management strategies as data become available. A mechanism for continuously reevaluating the data and information base in light of emerging alternative responses needs to be formalized. This evaluation should determine how well management goals are being achieved so that alterations in the whole problem-solving and data-gathering process can be implemented. Another crucial aspect of the iterative process involves analyzing the full range of possible alternatives, including those that appear to warrant further attention as well as those that appear flawed. This is helpful to the long-term success and eventual public acceptance of the chosen option. An analytical methodology to identify the diverse and often conflicting
IDENTIFYING AND EVALUATING ALTERNATIVES 117 environmental and economic considerations can be developed through iter- ative reevaluation. It aids in identifying and quantifying diverse elements. Iteration also provides a process for presenting relevant information and mechanisms for compromise (making the necessary trade-off. The public Is more likely to have confidence in the final decisions if they are made in a logical and open manner, following a process that has been carefully thought out and subjected to public review. REFERENCES Colby, B. G. 1988. Economic impacts of water law-state law and water market development in the southwest. Natural Resources Journal 28, 721-749. Frankenberger, W. T., Jr., and U. Karlson. 1988. Dissipation of Soil Selenium by Micro- bial Volatilization at Kesterson Reservoir. Final report, Project 7-FC-20-05240. U.S. Department of the Interior, Washington, D.C. Lee, E. W., G. H. Nishimura, and H. L. Hansen. 1988a. Agricultural Drainage Water Treatment, Reuse, and Disposal in the San Joaquin Valley of California, Part I: Treatment Technology. Technical report, San Joaquin Valley Drainage Program, 2800 Cottage Way, Rm. W-2143, Sacramento, California. Lee, E. W., G. H. Nishimura, and H. L. Hansen. 1988b. Agricultural Drainage Water Treatment, Reuse, and Disposal in the San Joaquin Valley of California, Part II: Reuse and Disposal. Technical report, San Joaquin Valley Drainage Program, 2800 Cottage Way, Rm. W-2143, Sacramento, California. Murphy, A. P. 1988. Removal of selenate from water by chemical reduction. Ind. Eng. Chem. Res. 27, 187-191. Parker, M. S., and A. W. Knight. 1989. Biological characterization of agricultural drainage evaporation ponds. Water Science and Engineering Paper No. 4521. Department of Land, Air, and Water Resources, UC-Davis. 51 pp. Phene, C. J., K. R. Davis, R. L. McCormick, and D. Heinrick. 1988. Subsurface Drip Irrigation: Management for Maximizing Yields and Reducing Drainage. Proceedings of Drip Irrigation Symposium, San Diego, California, pp. 34-54. Rhoades, J. D., F. T. gingham, J. Letey, A. R. Dedrick, M. Bean, G. J. Hoffman, W. J. Alves, R. V. Swain, and P. G. Pacheco. 1988. Reuse of drainage water for irrigation: Results of Imperial Valley study I. Hypothesis, experimental procedures and cropping results. Hilgardia 56~5), 1-16. Saliba, B. C., and D. B. Bush. 1987. Water Markets in Theory and Practice: Market Transfers, Water Values, and Public Policy. Westview Press, Boulder and London, pp. 64-65. Schroeder, R. A., D. U. Palawski, and J. P. Skorupa. 1988. Reconnaissance investigation of water quality, bottom sediments, and biota associated with irrigation drainage in the ll~lare Lake bed area, southern San Joaquin Valley, California, 1986-87. U.S. Geological Survey, Water Resources Investigations Report 88-4001. U.S. Geological Survey, Books and Open File Reports Section, Denver, Colorado. Tangi, K. K., M. E. Grismer, B. R. Hanson. 1985. Subsurface drainage evaporation ponds. California Agriculture 39~9 and 10), 10-12. van Schilfgaarde, J. 1982. The Wellton-Mohawk dilemma. Water Management and Supply 6~1/2), 115-127. van Schilfgaarde, J., L. Bernstein, J. D. Rhoades, and S. L. Rawlins. 1974. Irrigation management for salt control. J. Irrig. Drain. Div., ASCE 100(IR3), 321-338. Water Resources Council. 1973. Establishment of principles and standards for planning water and related land resources. Federal Register, Vol. 38, No. 174, Part III, September 10. Water Resources Council. 1983. Economic and environmental principles and guidelines for water and related land resources implementation studies. U.S. Army Corps of Engineers, Department of the Army, Circular No. 1105-2-115. 137 pp.