this reservoir system was managed so as to maintain a flow pattern in the Lower Basin within the framework of the flood control regulations for Hoover Dam. Effective management was possible because of foresight in developing this system so as to allow for surcharge at these reservoirs. This surcharging at Flaming Gorge Dam, Glen Canyon Dam, and Hoover Dam became a successful management tool that protected the lower reach of the River from receiving serious flooding. Mr. Chairman, the Upper Colorado River Commission believes that the long-term operation of the Colorado River system should continue to be based on providing conservation of our precious water resources for the benefit of all its users. Operation of the River should not be based on an extreme event, because over time this would prove wasteful and lessen the region's benefits from its limited water resources. It is our position that the Bureau of Reclamation has operated the Colorado River reservoir system successfully within the framework of the "Law of the River." We support the method used during Water Year 1983. Furthermore, we see no reason to change the "Law of the River" for future operations of the River system. We suggest that consideration be given to the development and enforcement of a flood plain management plan as a means of achieving Lower Basin protection against possible future high flows of the Colorado River. This would provide the desired protection for Lower Basin river front development while conserving the usability of the water resources of the Colorado River system. On behalf of the Upper Colorado River Commission, I thank you for the opportunity to present the Commission's views on these matters. STATEMENT Myron B. Holburt, Chief Engineer I appreciate the opportunity to submit to the Committee this statement regarding the management of Colorado River reservoirs during the 1982-83 water year. The Bureau of Reclamation (Bureau), Corps of Engineers (Corps), and the National Weather Service have presented statements covering many of the background aspects of Colorado River operations and events that resulted in the high flows of 1983. I plan to present mainly an overview and commentary on this year's operations and related matters. The Colorado River Board of California is the state agency charged with protecting the rights and interests of the state, its agencies and its citizens to the waters of the Colorado River system. The Board consists of eleven members that are appointed by the Governor: one from each of the six major public agencies having rights to the use of water or power from the Colorado River, three from the general public, and the Directors of the Departments of Water Resources and Fish and Game. The public agencies are: Coachella Valley Water District, Department of Water and Power of the City of Los Angeles, Imperial Irrigation District, Metropolitan Water District of Southern California, Palo Verde Irrigation District, and San Diego County Water Authority. River Management Commissioner Broadbent has described many of the documents that comprise the "Law of the River" in his statement. These documents describe the water and power rights and priorities of the seven basin states and the entities within those states, and the United States treaty obligation to Mexico. They also describe the procedures to be followed for the storage and release of water, and for flood control as well as other matters. The Secretary of the Interior follows the "Law of the River" in operating the river's reservoirs. In effect, he is the river's watermaster and he has delegated this responsibility to the Bureau. Presented before the House Committee on Interior and Insular Affairs, September 8, 1983 at Needles, California. The term "Law of the River" seems to imply to many people that the Colorado River operations are rigidly constrained. In some cases the directions are specific but, in other cases, they are very broad. With respect to those documents pertaining to river operations-the Hoover Dam Flood Control Regulations and Criteria for Coordinated Long Range Operation of Colorado River Reservoirs-the Bureau is allowed a considerable amount of flexibility in the manner in which it operates the river. Guided by the Corps of Engineers' flood control regulations and the National Weather Service's forecasts of runoff, the Bureau can vary operations based on its judgment. Specifically, it can release flows in excess of the minimum required by the regulations, develop flood control storage space greater than required, and shift required flood control storage space to different reservoirs. This flexibility is consistent with the authority given the Secretary of the Interior in the Boulder Canyon Project Act for the operation of Hoover Dam to control floods and to regulate the flow of the Colorado River so as to make its water available for beneficial use. 1983 River Operations by the Bureau of Reclamation The high flows released into the Lower Colorado River from Hoover Dam, commencing in June 1983, have been blamed by some people on the Bureau. The essential charge is that earlier in the year the reservoirs were kept too full and that the Bureau did not release enough water from the reservoirs. The test to be applied to this charge is one that Congress has applied before: What did the Bureau know and when did they know it? Commissioner Broadbent has provided the Committee a detailed account of the monthly forecasts of April-July runoff into Lake Powell, the water releases and other pertinent information starting on January 1, 1983. The account shows that based on all forecasts through May 1, there was no reason for the Bureau to release any more water than they did. The May forecast is usually the last forecast and is usually very reliable. To avoid damaging flows, the Bureau would have had to release high amounts as early as February. Furthermore, as illustrated in the following summary of events, the Bureau created more flood control space early in the year than required, released more water early in the year than required, and, when the high flows became critical, released with the concurrence of the Corps less damaging flows than allowed by the flood control regulations. 1. December, 1982 - The International Boundary and Water Commission was notified by the Bureau that it considered 1983 to be a surplus water year as defined by the U.S. - Mexico Water Treaty. This meant that Mexico could increase its scheduled deliveries in 1983 by 200,000 acrefeet. This action was based on a statistical probability analysis that showed that there was a probability that surplus water would be available. 2. January, 1983 There was 6.6 million acre-feet of vacant reservoir storage in the Colorado River system on January 1, about 25 percent more than the minimum required by the flood control regulations. 3. April and May, 1983 - About 600,000 acre-feet were released from reservoir storage in these months in excess of the releases required by the flood control regulations. These excess releases resulted in additional vacant reservoir storage space that aided the later efforts of the Bureau to limit flood flows in the lower Colorado River. 4. June and July, 1983 - The runoff forecasts increased dramatically from week to week during this period but the Bureau was able to keep the flow below Parker Dam at less than the 40,000 cubic feet per second desirable maximum release rate of the flood control regulations. During this period, the Bureau and Corps exercised their judgment in maintaining releases below the 40,000 cubic feet per second level, rather than increasing them up to the greater damaging flow rates of 65,000 to 70,000 cubic feet per second specified in the regulations. 5. During the floods, the Bureau initially installed wood flashboards and later constructed higher metal flash boards at Glen Canyon Dam which enabled Lake Powell to temporarily store an additional 1,370,000 acre-feet, thereby resulting in a reduction of flows below Hoover Dam. The Colorado River Board of California was consulted by the Bureau concerning the declaration of surplus for Mexico and the extra releases in April and May and agreed with the Bureau's decisions. The high flows in June and July were largely due to very unusual meterological events that occurred in the late spring and early summer. The net result of these high flows is that the 1983 water year runoff is projected to be the highest of record, going back to 1896. Statistically, the unique combination of events is probably even rarer than the one in a hundred year occurrence that is being preliminarily ascribed to the total volume of runoff. It is clear that the Bureau passes the test referred to earlier in this statement. They operated responsibly and did a fine job in coping with fast moving and unprecedented weather events. Flood Control Regulations by the Corps of Engineers Colonel Higbee has described the studies and report that were the basis for the Corps 1982 Hoover Dam Flood Control Regulations, which represent the third modification of the regulations in the history of Hoover Dam. Flood control operations at Hoover initially followed the plan that was developed before the dam was constructed. The plan provided for fixed amounts of storage being required on the first of each month with the minimum amount of required storage space available from August 1 to October 1. After that date, the storage requirement was increased each month until a maximum of 9,500,000 acre-feet of storage space was reached on April 1. This initial operation plan was formalized in a 1955 Corps of Engineers report, and was continued in effect until 1968. In that year, the Corps revised the Hoover Dam Flood Control Regulations to provide for using monthly inflow forecasts as a basis to determine required storage and releases. The change was made because refined forecasting techniques and construction of Upper Basin reservoirs made it possible to reduce the January 1 flood control storage space in Lake Mead specified in the earlier regulations by 500,000 acre-feet and to eliminate the fixed spring period storage space requirements in favor of a more flexible operation. The monthly inflow forecast used since 1968 gives a minimum and maximum April-July runoff forecast which includes 95 percent of possible future flows or, in other words, the range in forecast would not be exceeded in 19 out of 20 years. Under these regulations, a very high April 1 forecast would result in an April 1 storage space requirement of more than 9,500,000 acre-feet. Thus the current regulations could provide even a greater level of flood protection than did the fixed storage space schedule of the earlier regulations. The Corps presented nine alternative flood control operating plans for Hoover Dam in a 1981 draft report on the regulations. The recommended plan was similar to the previous operating plan in that it set a January 1 flood control storage requirement of 5,350,000 acre-feet. The adopted 1982 regulations are not a major change from the 1968 regulations. However, the following changes provided in the 1982 regulations improve the operations when compared to 1968 regulations: |