Agenda - 04-03-2001-10b - Laserfiche WebLink

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Jordan Lake Water Supply Allocation January 2001 Page 4 of 6 timing of this is known. At that time, the historic trend of increasing water demands would level off at a demand of between 16 and 22 MGD (not depicted on this graph, which extends only to 2035). Rate of Quarry Expansion and Ultimate Capacity -The ultimate yield of the Quarry Reservoir will depend on its water storage capacity. Sustainable yield projections illustrated in the attached figure are based on a final capacity of 3 BG. The current capacity of ,American Stone's active quarry is approximately 1 BG. OWASA's existing Quarry Reservoir has a storage volume of 0.2 BG. American Stone's agreement with OWASA contains a "due diligence" commitment to maintain rock production at an average rate of 650,000 tons per year, which corresponds to a quarry pit volume increase of 0.065 billion gallons per year. At this rate, quarry volume will increase by 1.95 BG over the next 30 years, providing a total volume of slightly more than 3 BG. If -due to economic conditions, market competition, or changes in corporate policy -American Stone's production activity decreased below this level, or if the company went out of business arid stopped production altogether, then the usable storage volume and resulting water supply yield would be less than what has been projected. Meteorological Variation and Climatic Change -The sustainable yield estimates calculated for OWASA's existing and future raw water supply system were based on historic temperature and streamflow records that reflect the natural variation and uncertainty characteristic of such observations. To the extent that future weather conditions differ from the historic range -- reflecting either short term variation or longer term climatic changes -the yield of OWASA's water supply system will differ from what has been projected. Is There Still a Rale for Jordan.Lake in OWASA's Water Supply Fntnre? Even assuming the anticipated approval of the Extended Stone Quarry Reservoir, OWASA faces a potential 1 to 3 MGD water supply shortfall for a period of several years before the new 3 BG Quarry Reservoir can be put into service. If any conditions of service area growth, quarry production rates, or 30-year weather trends differ fmm those that have been assumed, the extent and duration ofthe water supply shortfall may be greater or lesser. In keeping with OWASA's past practices and with industry standards of maintaining as many viable and reliable water supply options as possible, OWASA should retain at least a portion of its Jordan Lake water supply allocation. How Much? It is clear from the EMC's application requirements that the new round of allocations will be based on a more rigorous analysis of demand forecasts and supply alternatives than has been applied in the past. It is unlikely that allgcations will be issued in the absence of thorough and credible demonstrations of need, which have been provided in the application materials. Because OWASA recognizes tl:at its anticipated needs do not warrant the full IO~MGD Level II allocation that it currently holds, the draft application voluntarily offers to adjust OWASA's allocation downward to S MGD.