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3 WHAT ARE ACCEPTABLE RISKS FOR PUBLIC SYSTEMS? Duane L. Georgeson Los Angeles Department of Water and Power Los Angeles, California The subject of drought management in the context of risk assessment is a relatively new concept in terms of urban water supply planning. Simply stated, the concept of drought management would be to plan for a water supply that would be available at all times except during droughts with some calculated recurrence interval, say once in 50 years or once In _ . . . . ~ ~ _ 100 years. Determining an appropriate drought recurrence interval for water supply planning is extremely difficult due to the highly unpredictable nature of droughts. This discussion briefly describes some of the problems associated with this type of risk analysis and examines some practical drought management strategies in the context of past experiences and necessary future planning. FLOOD MANAGEMENT PLANNING Although risk assessment has been applied to flood damage mitigation for many years, there is-no simple formula, such as one percent chance of exceedence, that can be applied to all situations. The planning of flood mitigation facilities is far more complex and rightly so. For example, along California's largest intrastate river, the Sacramento, some agricultural lands are inundated every two or three years by flood waters that overflow at seven control structures, ~ cost of flood control along the river the Sacramento-San Joaquin Delta area below-sea-level islands protected by delta islands, composed of primarily agricultural lands with some urban development, experience flood perhaps thus reducing the There is also in a complex of levees. These -49-
-50- every 20 years. Although most urban flood control facilities are designed to accommodate a 100-year flood, certain other structures, such as dam embankments and spillways, are often designed to safely pass the probable maximum flood that approximates a 1000-vear recurrence interval. Because of the potential of catastrophic loss of life and property damage associated with dam failure, particularly in urban areas, public policy dictates that special consideration be given to the construction of dams. Similarly, no set recurrence level can be used for . · . trough planning. the ~mposs'n~l~ty at predicting bow and when a drought will unfold and the problems of applying uniform measures to deal with the drought make risk assessment very difficult. During drought periods, various management strategies have been employed to allocate an inadequate water supply among competing users for that supply. AGRICULTURAL DROUGHT MANAGEMENT One example of drought management applied to agricultural water users is the U.S. Bureau of Reclamation's Central Valley Project in California, which serves almost 3 million acres of land. The Central Valley Project has "firm" water or Class 1 water available in most years, and in addition has Class 2 water that is available on a "less firm" basis. In dry years, when little or no Class 2 water is available, the farmers have the option of reducing their irrigated acreage of annual crops or increasing their production from alternative supplies such as individual wells. The Bureau's system. in eeneral. works well: however the example above does not fit the typical urban situation, since most urban water users neither make an explicit annual decision on their needs for domestic water or water-using vegetation nor do they have the option of turning to individual wells. Also, while a contract system might work fine for a few hundred to a few thousand agricultural water users, it has some obvious limitations for an urban setting with hundreds of thousands of small customers.
-51- THE GREAT CALIFORNIA DROUGHT OF 1976-1977 From November 1975 through November 1977, California experienced its most severe drought of this century. Although most of the urban and farming areas are accustomed to the almost total absence of precipitation during the growing season from April through October, in 1976 and 1977 the winter periods experienced only one-half and one-third of normal precipitation, respectively. The result was California's fourth driest and driest years of record, successively. Most surface storage reservoirs were substantially drained in 1976, with the result that there were widespread shortages when 1977 turned out to be even drier. Many dramatic and imaginative programs were implemented by federal, state, and local officials, as well as private companies, farmers, and individuals to cope with the water shortage. In general, the public response and cooperation were outstanding because the evidence of shortage was clear and uncontrovertible--bare ski slopes in the winter and empty lakes and reservoirs in the summer. Southern California with its access to the giant Colorado River reservoirs at Lake Mead and Lake Powell was less hard hit than the normally wetter areas of Central and Northern California (interestingly, the Colorado River also experienced its driest year in recorded history in 1977~. As a result, Southern California was able to give up substantial quantities of its contracted rights to water from the State Water Project to assist the San Francisco Bay area (approximately 40 billion gallons) and the San Joaquin Valley farmers (approximately 100 billion gallons). The cost of the two-year drought has been estimated at $2.5 billion, with those hardest hit economically being businesses directly dependent on precipitation--cattle ranches and recreational facilities, particularly ski resorts. Also hard hit was hydroelectric generation in Northern California (only 38 percent of normal), with replacement made up at much higher cost from burning increased quantities of fossil fuels at Southern California plants for export to Northern California. The impact on farm production, other than range cattle, was substantially lessened by the increased use of ground water with accompanying higher costs. It has been estimated that up to 10,000 new wells were drilled or deepened to provide replacement agricultural water. , .
-52- (See Table 3-1 for a comparison of agricultural production in 1977 with the previous three years.) Much media attention was received by the urban water conservation programs in California during the drought, and in particular, the programs in Marin County, where, due to a particularly severe supply deficiency, water use was reduced by approximately 65 percent to only 45 gallons per person per day. However, other urban water customers throughout California also enthusiastically cut their water use as can be seen on Table 3-2. Public opinion polls in water-short areas during 1977 determined that city dwellers had substantial sympathy for the plight of the farmers and frequently stated the opinion that the urban water user could more easily conserve than the farmers. TABLE 3-1 Agricultural Response to Drought Field Fruit- and Nut- Vegetables Year Crops Bearing Crops and Melons Total - . Acreage 1974 6,520,300 1,508,010 861,320 8,889,630 1975 6,602,000 1,571,440 921,660 9,095,100 1976 6,590,000 1,634,540 829,466 9,054,006 1977 6,359,000 1,673,890 914,652 8,947,542 Production (tons) 24,986,000 8,702,700 11,820,750 45,509,450 28,566,000 9,794,800 13,312,050 51,672,850 28,965,000 9,626,600 11,051,650 49,643,250 25,009,000 9,673,700 13,037,750 47,720,450 This table displays the harvested acreage and production of the principal crop groups in California during the drought of 1976-1977 as compared with the two previous years. These figures include both irrigated and dry farm acreage and production. As indicated, acreage and production actually increased in the drought year 1977 for fruit- and nut-bearing crops, vegetables, and melons SOURCE: From The California Water Atlas (1978~.
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-55- DEVELOPMENTS SINCE 1977 Because of the dramatic urban water conservation achievements during the drought there was, during 1977, substantial debate regarding whether the per capita water use assumptions for water planning should be substantially reduced to reflect an enlightened new "urban water ethic." Unfortunately, water use habits of Californians, from both the north and south, have proved difficult to modify. Table 3-3 shows that per capita water use has returned to near predrought levels in most cities, even though many cities continue with water conservation programs. A recent news article reported that even though water use in Marin County had returned to predrought levels, the public perception was that they were still conserving. In one survey, 45 percent of the people responded that they were already doing all that they could do to conserve. Another survey in California determined that 80 percent of respondents felt that substantial water could be conserved, but only 30 percent believed that they personally could conserve water. Another interesting development relates to the public's growing recognition that 85 percent of the agriculture and that less than 15 percent is used for all urban purposes. Much attention has focused on the alleged waste of water bY the Imnerial Irritation District. the water used in California is used for ~ . ~ largest agricultural district in California. As a result of continuing pressure, preliminary approval has been given to a plan to conserve 100,000 acre feet per year (approximately 90 million gallons per day) by lining canals and reducing water losses. The conserved water would be made available to urban Southern California, which would reimburse Imperial $10 million annually to develop the conservation programs. This proposed transaction has stimulated a growing debate regarding the need for developing a "free market" to permit water to be sold to the highest bidder, just as any other commodity. WATER PLANNING IN CALIFORNIA Most urban areas of California, whether the San Francisco Bay area or Los Angeles or San Diego, depend
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-57- for most of their water on long aqueducts from either the Sierra Nevada, the Sacramento Delta, or the Colorado River. In addition, there are 9 million acres of irrigated lands that are also supported by similar aqueduct systems moving water great distances (see Figure 3-1~. The management of California water systems involves all levels of government--federal, state, 20 different special districts, counties, cities, the other six states of the Colorado Basin, and even Mexico. The abundance of water in the rural north and the need for water in the more arid areas from San Francisco south gives most major water planning activities a statewide character. For that reason, the state legislature has been the focal point of three me jar efforts in the last eight years to develop a statewide program to complete the State Water Project, which voters approved narrowly in 1960 and which today can meet only one-half of its contractual commitments. Although one of these legislative proposals was approved by 60 percent of the legislators in 1980, it was subsequently repealed in a statewide referendum, which 6~0 percent of southern- voters approved but which 90 percent of northerners rejected. The extreme difficulty of achieving a statewide consensus on water development in the face of continued population and economic growth, together with the future loss to Arizona of more water than is used by the City of Los Angeles, raises the specter of more frequent drought shortages in the years ahead. There is little question that all aspects of drought management will get increasing attention from water professionals, environmental organizations, and government leaders, but how the decision-making will take place is difficult to forecast. POTENTIAL CONSEQUENCE S OF URBAN WATER SHORTAGE S Serious consideration needs to be given to the potential magnitude of the urban water shortage in order to consider which decision-makers should be involved in deciding what constitutes acceptable risk for shortages. For example, if the shortage is to be one of limited duration or severity that can be accommodated by short-ter~ conservation programs (such as odd and even days for lawn watering), perhaps such decisions could be
58 SHASTA (USBR) ...... ·..l, . . : : i,` ~ " " i._-_ ~ A. ·.l'. {''''" ~~ ~3 . ; w r~S,~,~''' ;_- , ~ ~LU~NE (E.~.~.U.De) _\~HETCH HETCHY (8.F.) SAN FRANCISCO ~ it: ,~`DELYA-~ENDOTi`(U4R.) ~ jRIAN4KERN 4.R.) CALIF. A..... ....... ...... _' . ~--~-~- :- ~ os A~ FIGURE 3-1 California water transfer facilities. \LOS ANGE4. (L.~.) .. .... \. ,,_ .1 I_ - ·:--.~ 1 A\ . t ~ W. :_ ~ ·: C;. ." ~ : .: : a. .. _ .
-59- made by the local water utility board. On the other hand, if the potential water shortage would necessitate "Hong Kong" type rationing, where the public water supply system would operate only a few hours per day to conserve a very limited resource, the decisions should be made by general government and elected officials, since important public safety considerations are involved. (Profound impacts on the public include diminished fire protection and greater contamination threats because of backflow potential into unpressurized water mains.) Even if the potential water shortage is well short of a "Hong Kong" type of shortage, local government should almost certainly be involved in the planning stages, since many of the drought management options require the leadership of top elected officials to convince the public of their necessity. Other options require the exercise of police powers, which are available to local general government, but which are usually not available to the local water utility board. URBAN AND AGRICULTURAL COMPETITION AND COOPERATION Following the drought of 1977, there developed some support for the notion that urban water users are more able to conserve than farmers and perhaps contractual provisions which require agriculture to take the first shortages should be reversed to require urban users to accept initial shortages. As discussed above, urban users developed substantial sympathy for water-short farmers during the 1977 drought. Whether this sympathy would have continued into 1978, if it had been a third dry year, is very uncertain particularly if urban users had become generally aware that total irrigated acreage slipped very little in 1977 and that productivity actually increased in several major areas (see Table 3-1~. In normal water supply years, over 10 million acre feet per year of water is used to irrigate alfalfa and cotton. Some critics of California water development have suggested that, since these crops have a gross value of only about $1 billion per year or about $100 per acre foot, during drought periods alfalfa and cotton production could be curtailed to provide water (at a profit to the alfalfa and cotton farmers) for urban users and higher valued agricultural commodities. These simplistic proposals, however, fail to consider that
-60- while such financial transactions might be very appealing, they do not usually suggest any form of compensation to third parties such as farm workers, crop dusters, farm equipment dealers, and the myriad other support businesses and employees. Even local governments have their concerns because of potentially reduced tax levies and increased welfare costs e A more likely, near-term, scenario of urban and agricultural cooperation would be expansion of the above-mentioned pending transaction between the Imperial Valley and the Metropolitan Water District of Southern California. The concept of using urban dollars to increase the efficiency of agricultural water use while maintaining farm production provides a win-win-win solution including benefits, not detriments to virtually all third parties including workers, support businesses, and even local tax collectors. PUBLIC COMMITMENT As discussed, the success that urban areas in California achieved in reducing water use (see Table 3-2) has lead to speculation that sharp reductions in urban use could be easily achieved again in the future. Water planners and those involved in public policy development in this area should keep in mind that mandatory conservation and rationing programs lasted a relatively short time. By early November 1977, when heavy statewide precipitation mercifully arrived, most urban water customers and public officials were growing weary of the problems and nuisances of living with the water shortage. For example, in the City of Los Angeles, which had implemented water rationing for the first time in the 75-year history of the municipal water system, 85 percent of the water customers were meeting their water conservation goals; however, this still left approximately 100,000 different residential, commercial, and industrial customers who were in violation. Under the City's Emergency Water Conservation Plan (see Appendix A), these 100,000 customers were scheduled to have flow restrictors installed on their service lines during November and December of 1977 at a minimum charge of $25 per customer. The logistics of such an effort and the enormous customer relations problem associated with it would almost certainly have forced the Los Angeles City Council to modify this portion of the
-61- emergency plan, and of course any weakening of the plan would bring loud complaints from the 85 percent of the customers who were, at some expense and inconvenience, meeting the plan's requirements. The experiences with emergency water ordinances in Marin County, San Francisco, and dozens of other California communities were very similar to that being experienced in Los Angeles. One can only speculate on the political, administrative' legal, and other problems that would have resulted if the drought had extended through 1978. As discussed above, it is very likely that the continuing high rate of agricultural water use in California would eventually have come to the attention of urban areas and very likely undermined the enthusiasm of urban areas for maintaining the increasingly less popular restrictions. The success of urban water conservation in 1977 was undoubtedly due to the public recognition of a real and widespread problem and the perception that water restrictions and penalties were being fairly administered. Public commitment to water conservation would likely erode quickly if financial penalties and other restrictions were perceived as not being enforced. For example, water agencies in New Jersey experienced substantial public backlash a few years ago when financial penalties imposed during the drought on a number of large customers were waived upon easing of the drought. WATER AGENCY RESPONSIBILITY If the public feels that water agencies are managing water supplies responsibly and efficiently, they will be more likely to support proposed conservation measures in emergency situations. The ability to extend supplies during water-short periods is important to public confidence. One important way to extend water supplies and increase flexibility during emergency situations is through the increased use of ground-water storage basins. Additional wells and distribution lines can be constructed to give greater ability to pump ground water when other sources grow scarce. Conversely, pumping can be curtailed in wet periods and recharge programs can be expanded to ensure that basins will be adequately full to handle emergency situations.
-62- FINANCIAL AND INSTIfUTIONAL PROBLEMS In California, with its multitude of different levels of water agencies, there are major legal and contractual problems associated with drought management planning. In Southern California, there is a large wholesale water agency, California (MWD), which provides supplemental water to Los Angeles, San Diego, and 24 other cities and water district. ~ The MW1) Ant nr~vi H~.c ~ ' ~ ~ ' the Metropolitan Water District of Southern r ~ ~ ~ _ _ _ ~ r~~~~~~~ Gnat each member agency has a preferential right to purchase water based on the proportion of property taxes paid by each member agency. When the 1977 drought occurred, the City of Los Angeles had a preferential right to 30 percent of the MWD supply, and San Diego County had a right to 10 percent of that supply. (Normally, Los Angeles uses only 2 percent of the supply, and San Diego uses 25 percent.) However, during 1977 for a variety of complicated legal and political reasons, the City of Los Angeles imposed water rationing and was able to limit its use of MWD water to approximately 7 percent of the HWD supply, or one-fourth of its legal right, whereas San Diego did not impose rationing and purchased 27 percent of the MWD supply or almost 3 times its legal right. There is no suggestion of impropriety on San Diego's part intended by these remarks, merely a statement of what took place during the 1977 drought. It is likely that the events of 1977 would receive considerable attention when a water shortage within the MWD service area occurs at some future time. This issue remains a matter of considerable interest in both Los Angeles and San Diego, since Los Angeles continues to pay property taxes that are approximately $19 million per year, and San Diego only pays $10 million. There is also extensive debate with MWD at the present time as to whether the entire preferential right concept should be modified or abolished, given the fact that preferential rights have never been used to allocate water during a time of shortage. Solutions with acceptable public risks for drought management are elusive. The above example has been debated for more than two decades. The hundreds of other water agencies throughout California have institutional and financial relationships of similar complexity. v - - . .
-63- DROUGHT MANAGEMENT DECISION-MAKING Since the consequences of urban water shortages are potentially very serious and involve great numbers of people, the decision-making unquestionably must take place by the elected officials. Given the great uncertainty about the timing or severity of future droughts, water officials are understandably reluctant to "cry wolf" and urge elected officials to immediately begin development of what would have to be fairly complicated water curtailment ordinances. There is a concern that pressure by the water managers for such ordinances would be perceived as merely a poorly disguised "hype" for additional expensive water projects. In the case of the City of Los Angeles, there is an existing Emergency Water Conservation Ordinance (see Aonendix A), which was hastily developed during the spring of 1977 to deal with the water shortage of that time. Although the ordinance is far from perfect, it at least provides a standby mechanism that could be triggered in the event of some future water shortage and perhaps fine-tuned on rather short notice. Other cities and counties that do not currently have in place such ordinances will probably do as Los Angeles did, namely, wait to implement such a plan until conditions demand such action. Leaving the development of water curtailment ordinances to over 100 cities and counties in Southern California is clearly a fragmented approach to dealing with a regional problem; however, since the regional agency, MOOD, is a special district without the police powers of general purpose government, it is difficult to conceive how regional water curtailment plans could be implemented even in the presence of a severe drought. The same is true for a statewide water curtailment program. Although the state legislature has adequate police power, the water supply issues become almost hopelessly complicated with thousands of different water purveyors with vastly different circumstances and involving both agriculture and urban water supplies. CONCLUDING REMARKS The experience of the 1976-1977 drought in California demonstrated that, at least over a limited period of approximately 6 months, urban areas are capable of
-64- achieving imaginative and substantial reduction in water use. It is far from clear how the achievements of 1977 can be translated into some rational quantitative risk management approach to water supply planning, given the impossibility of predicting when and how future droughts will unfold. Perhaps, the best that can be achieved is for the water managers to be familiar with the variety of strategies that succeeded and those that failed for implementation of appropriate ones on an ad hoc basis during future water shortages. As crises occur, drought management will continue to improve as we build upon past experiences. California in 1985 is experiencing a year almost as dry as 1976. The hot, dry weather is causing reservoir levels to drop sharply throughout the state (with the exception of the Colorado River, which this year is above normal) causing farmers and city dwellers to wonder whether 1986 will bring the repeat of 1976-1977 drought. Perhaps by September 1986, California will have some new chapters to add to our drought contingency plans and perhaps the subject-of drought management will be receiving even greater attention than it is today. REFERENCE Governor's Office of Planning and Research in Cooperation with the California Department of Water Resources. 1978. The California Water Atlas. Sacramento, California.
