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I I I I I I I I I I I I I I I I I I I The river section downstream of the diversion has been rated to determine the flow at different gauge heights. However, the date of the rating and the accuracy are in question. The allocation of water in the Poudre River system is based on f11ling senior direct diversion rights in order of priority or order of rank within the system. This system of f11ling the water right with the highest priority fIrst is essentially followed. However, in wet years, reservoirs in the system are often f11led out of order. During an operating season, The New Cache La Poudre system operates in the following manner. As flows begin to rise on the Poudre in the spring, senior decrees are maintained below the diversion and as much river flow as possible is diverted into Fossil Creek Reservoir. Fossil Creek Reservoir acts as an "equalizer structure" to contain peak flows. As flows continue to increase, NCLPIC begins diverting into their canal. When flows exceed the capacity of their canal, the overflow gates on the diversion structure are opened to pass water downstream. The canal flows through Windsor Lake, which acts as an equalizer basin and provides for more constant flows downstream of the lake. The Company continues to use their direct diversion rights as long as possible. This typically lasts about seven weeks, ending in late June. At that time, the Company begins releasing water from the reservoirs. These include Timnath Reservoir, Fossil Creek Reservoir, and Windsor Reservoir. Agreements for renting water are made with the North Poudre Irrigation Company for Fossil Creek and with Larimer- Weld for Windsor. NCLPIC has traditionally operated the main canal under the assumption that seepage depletes about 30% of the total flow rate. It is believed that the losses from upstream irrigation, which do not drain back into the Poudre River, constitutes this seepage loss. During dry irrigation seasons, this creates management problems for the Company not only in terms of increased demand for water but also due to a potential reduction in return flows that have traditionally been relied upon to stabilize the main canal's head during the season. Water Records. Summaries of several years of diversion records for the canal are shown on Figures IV-2 through IV-7. The maximum diversion rate recorded since 1987 was 465 cfs. Table IV-2 shows the Peak Flows in the Poudre River before any diversions, the peak flows diverted by the canal, and the total diverted flow for the NCLPIC diversion structure. PAGE-) . Chapter IV