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Examples of natural disasters that jeopardize South System water supply include forest fires, landslides, earthquakes, and floods. Manmade disasters include terrorism, and chemical spills. After the 1996 Buffalo Creek fire, a major rainstorm and subsequent runoff containing ash, sediment, and debris, seriously impaired the quality of water entering Strontia Springs Reservoir, restricting significantly the treatment rate at the Foothills and Marston treatment plants, These two treatment plants treat all of the water derived from the South System. If this natural disaster had occurred during a drought, or the fire and subsequent flooding had been more severe, or another mishap had occurred in the system, Denver Water's ability to meet its customers' water demands would have been jeopardized, The terrorist attack of September II, 200 I, has forced all utilities to consider new kinds of vulnerabilities, Denver Water has just completed a vulnerability assessment required by federal legislation passed in 2002, Obviously, the ability to satisfy water demands from more than one source and enhanced operational flexibility are essential to reduce Denver Water's vulnerability to this type of event. System failures include the failure of pipes and tunnels, reservoirs, treatment plants, pipelines, valve malfunctions, and electrical failure. An example of such a failure is the 1996 Roberts Tunnel valve and powerhouse flood caused by a burst in the domestic water supply line in the valve and powerhouse. Deliveries of water from the Roberts Tunnel were suspended for several weeks while the control equipment to operate the valves and generate power was replaced. The Flexibility Problem Both Denver Water's treated water transmission and distribution system and its source water collection system are subject to outages caused by routine maintenance, pipe failures, treatment process problems, power outages and a host of other predictable and unpredictable occurrences inherent in operating and maintaining a large municipal water supply system. For these reasons the system seldom operates at full capacity. Maintenance-required shutdowns or outages can reduce supply availability from the South Collection System, necessitating more use of Moffat Collection System supplies, A greater degree of operational flexibility is needed to keep these factors from impairing Denver Water's ability to satisfy its customers' water needs. However since the Moffat Collection System is supply short, Denver Water is constrained in its ability to load shift to the Moffat Treatment Plant under such circumstances. In short, even though Denver Water has three treatment plants and two main collection systems, there is insufficient water supply presently available from the Moffat Collection System to provide the needed range of operational flexibility to meet customer demands. Problem Summary The flexibility, vulnerability, and reliability problems all compromise Denver Water's ability to provide existing customers a safe, dependable water supply. By developing 18,000 acre-feet of firm yield needed for meeting future customer demands within the 6 C:\Documents and Settings\vyp\Local Settings\Tempora'Y Internet Files\OLKI50\MoffatSystemIOO603.doc