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OVERVIEW AND CONCLUSIONS Humankind Is in a continuous struggle with a vast range of natural hazards. Many of these hazards (e.g., floods, earthquakes, tornadoes, and hurricanes) are encountered as short-duration, high-intensity, and relatively localized events. In this country, most research and formal emergency planning procedures are directed toward damage mitigation and rehabilitation needs associated with such events. Drought is different in that it seldom has a spectacular or sudden onslaught. Damage inflicted by drought usually occurs rather subtly over a span of months to years instead of minutes to days. Truly serious drought is usually a regionalized--as contrasted to localized--trauma, with the attendant need to broaden preplanning and mitigation efforts. A precise definition of drought is difficult, because the meaningful threshold of significant moisture deficiency is a function of the water use being impacted. For the purpose of the colloquium, drought was considered to represent a period of time when streamflows, reservoir storage, and shallow ground-water levels are abnormally low as a result of climatically- induced moisture deficiency. Drought severity as it relates to public water systems is necessarily a function of human actions and/or inactions as well as the magnitude and duration of the individual hydrologic event. There is need to direct both research and pragmatic mitigation efforts toward the neglected problems of water management during drought episodes. This colloquium was limited to the subject of drought as it affects the management of public water systems. The observations and recommendations summarized herein 1

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2 reflect that constraint. No attempt has been made to capture individual views. Instead, emphasis has been placed on those points for which a general consensus was identified in the floor discussion. Research Concerns There are numerous areas of inquiry where research can be expected to be productive. Categories of primary interest include cause and effect aspects of the drought mechanism, the probability distribution of drought events, measurement of the consequences of system failure, and the legal aspects of drought management. Our lack of ability to provide a firm rationale and explanation of the drought mechanism impedes efforts to develop reliable alert systems. The development of such systems would represent a crucial step toward implementation of effective and efficient drought contingency plans. Our present capability to predict drought appears to be confined to empirical equations relating such factors as sunspot numbers to streamflow and various physical anomalies, such as sea surface temperature and the positioning of land-based high-pressure centers, and to projected precipitation patterns. Though such correlations have been well documented, why or when these relations trigger the occurrence of significant drought is not understood. Analysis of drought frequency relationships has lagged appreciably behind the companion efforts related to flood discharge. There are several reasons for this, not the least of which relates to difficulties associated with the definition of drought. Annual peak discharges are a meaningful measure of flood size and are easily identified for purposes of flood frequency analysis. Neither minimum instantaneous flows nor lowest daily Round-water levels provide a meaningful measure of and the magnitude ot flow oet~c~ency anti/or moisture availability must be known in order to characterize a drought. Clearly, design of water supply system components based on drought of record begs the issue. Tree ring analyses have suggested the possible occurrence of historic droughts more severe than those readily documented by available flow records in this country. Nonetheless, we need to develop our knowledge of drought occurrence, for such knowledge is a , ~ , ~ of the magnitude of drought. Both the duration

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3 prerequisite for effective analysis of drought management alternatives. Equally key to the analysis of drought management alternatives are valid assessments of the costs associated with different types and durations of system failure. Several difficulties are encountered in attempting to develop generalized and transferable relationships. First, certain costs can be very site specific. Second, acquisition of firm data is difficult until a drought is encountered. Third, the average time span between significant droughts for a given system may be so long that the local economic and social patterns, and thereby the potential consequences of different types of system failure, may have changed appreciably. These obstacles should not be allowed to deter continued inquiry. Though they may work against the quantification of well-defined cost benchmarks, they do not lessen the need to develop methodological concepts to allow for an orderly process of analysis of alternative management strategies. Proper institutional arrangements can facilitate effective management of water supplies during drought periods. Conversely, inadequate or unwieldy institutional frameworks can effectively destroy the most industrious of management efforts. Since the management of public water systems is primarily a local responsibility, research is needed on the powers local authorities require to implement effective drought management programs. In addition, legislation at other than the local level can either expedite or constrain effective management choices. Little research has been directed at the effectiveness or influence exerted by different state laws and/or subregional, state, and interstate organizational structures during droughts. Management Concerns A wide range of decision issues was touched upon during the formal presentations and subsequent floor discussion. They generally can be categorized as follows: appraisal of risk, choosing between relying on supplemental supplies or relying on the management of demand, social aspects of demand management, water transfers from other uses, and other regional solutions. There was consensus that a uniform level of hydrologic risk should not be advocated as a design or decision

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4 parameter for a variety of reasons. The use of this approach in floodplain management has discouraged rational evaluation of floodplain productivity. In addition, the risk of system failure could be as sensitive to the quality of system maintenance as to variations in hydrologic events. Consideration of scale also influences this decision. That is, a small system can, from solely a logistic consideration, accept a higher risk of having to resort to emergency supplies than can a large system. Finally, site-specific considerations must be taken into account. A system with little access to alternative or emergency supplies must seek a more risk-free environment than one not so constrained. Despite lack of unanimity as to what constitutes an acceptable risk, there was general support for the need to integrate risk analysis into system planning as opposed to basing evaluations solely on the drought of record. Without risk appraisal, quantitative comparison of trade-offs between investments in supplemental emergency sources and demand management techniques could be meaningless. Application of demand management techniques should increase as the relative risk of system failure, especially the hydrologic portions thereof, decreases. This concept is supported by the recent trend in legal liability decisions that suggest the designer or planner could well be required to keep the risk of ~ ~ - general agreement management should capitalize on the decades of evolution in trade-off analysis that has taken place in the overall field of water resources planning. A primary prerequisite is development of an orderly and systematic matrix for analysis, and a current constraint is the lack of reliable data for quantifying the consequences of system failure. Several major considerations surfaced in the comments related to implementation of demand management techniques. First, there is little evidence these techniques will produce a continued reduction in water demand in postemergency conditions. The public obviously feels that such reductions do, indeed, adversely affect the quality of life and finds them unacceptable in the long term. Second, public cooperation in implementing demand management techniques has been shown to be excellent provided there is clear evidence of need. Third, the successful implementation r hydra ~ og~c system failure low. There was that system planning for drought

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5 of demand management techniques requires an adequate legal foundation. These factors must be understood by managers developing drought contingency plans. Appreciable attention was directed toward the possible diversion of water from other uses, primarily agriculture, as a means of mitigating public system drought issues. The legal concept is well established via the route of condemnation, but implementation can lead to much acrimony and is often costly and time consuming. Two alternative approaches, responsive to different physical situations, were examined and found attractive. In the case of large, rapidly growing urbanized regions, the projected transfers may be so large as to have an impact on the associated agribusiness industry. In this case, urban investment in conservation facilities for agriculture in return for the water saved has been found attractive to all three parties (i.e., the public system, the irrigator, and the related agribusiness interests). For many systems, the problem is quite different: existing sources are adequate for most years. The agricultural transfer is not needed on a permanent basis. In such cases, negotiated lease transfers wherein the irrigator is provided an initial signing bonus and then compensated for each subsequent year his water is used have proven successful. Legal Concerns Several legal concerns surfaced during the presentations, some of which have already been noted. Matters of primary concern to public systems confronted with drought management issues relate to questions of authority, water transfer, and constraints imposed by state or federal actions. Several participants in the colloquium emphasized the need for public systems to have their legal house in order before the onset of drought. The point was made that, in some instances, this might require a regional approach. Of main concern is the system's ability to initiate demand management techniques involving voluntary or mandatory conservation, revised rate schedules, or imposition of penalties. For publicly operated systems, this can be handled by the pre-enactment of a drought contingency ordinance that spells out the authority granted and the actions

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6 permitted. Privately operated systems, in the absence of supporting ordinances from local government, can establish the necessary authority via contractual arrangements with individual customers. The need for system managers to be aware of the status of their water rights, and the related state administrative and judicial procedures, was stressed. In this light, system managers should explore ways of increasing system yield within the confines of existing rights and seek administrative or legislative relief if unnecessary and ill-advised constraints are encountered. For example, conjunctive use of ground and surface waters is not widely practiced, although the practical advantage of conjunctive management is quite clear. Often its successful implementation would require a higher maximum rate of withdrawal from the ground water during the drought, although the overall demand on the ground water through the combined wet and dry cycle would be reduced. In such cases, existing administrative and legislative policies may prohibit implementation of a conjunctive use pattern. Public system managers need to move to lessen such constraints. There is every reason to believe that an increasing number of water supply problems will be resolved via water transfers. Again, the point was made that these solutions may need to be appraised in a regional context. This phrase "water transfer" may relate to change of use or to change of location or both. Public system managers need to know about the legal controls relating to such transfers. Where the need for transfer is of limited duration, the use of leases as described above deserves exploration. The competition for water has prompted the enactment of various state statutes concerning both intrastate and interstate transfer of waters. Judicial interpretation of these statutes is undergoing rather rapid evolution. Similarly, recent decisions citing the public trust doctrine may have an impact on water allocation issues. These several matters deserve continued examination. Conclusions 1. There is substantial need for continued research on drought and its impact on the management of public water systems. Key research topics include (a) cause of drought, (b) development of effective drought alert

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mechanisms, (c) probability analysis of drought, (d) quantification of the consequences of system failure during drought, and (e) identification of the institutional environment necessary for successful implementation of drought management plans. Federal agencies, universities, the water supply industry, and private foundations should all support research in these areas. 2. Sizing of the physical facilities of a system should not be based solely on full-service requirements during the drought of record, nor should such facilities be sized by the arbitrary specification of hydrologic risk. The reasons are many and range from the inadequacy of existing records to individual system characteristics. Instead, the measure of facility adequacy should be established by orderly comparison of incremental facility requirements versus the use of demand management techniques over the range of probability conditions. As the risk of system inadequacy decreases, the relative advantage of demand management techniques can be expected to increase. 3. The key to adequate drought management of public water systems lies in predrought preparation. This consists of a variety of actions best typified as drought contingency planning, including (a) a good system maintenance program, (b) periodic assessment of system capacity and the relative balance among all system components (source, transmission, treatment, and distribution), (c) identification and appraisal of the reliability of emergency or supplemental sources of supply, (d) analysis of the probable effectiveness of demand management techniques and determination of criteria for implementation, (e) development of the framework of public information programs needed to implement drought management measures, and (f) establishment of the legal foundation necessary to implement emergency source plans and projected demand management techniques.

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