WSPP358 - Laserfiche WebLink

Home Browse Search

UOJGG8 Ms. Maryanne C. Bach 12/28/98 Page 2 TABLE II - Biue River Water Diversions and Utilization This table shows monthly totals, in acre-feet, for the 1998 water year for Denver's deliveries of Blue River water through the Roberts Tunnel. These figures include water withdrawn from storage in Dillon Reservoir and water diverted directly from the Blue River. Also shown are monthly totals for: I) carrying charges assessed by the State Engineer on deliveries, 2) the portion of the Roberts Tunnel discharge delivered or exchanged into South Platte storage, 3) the portion used directly, and 4) the amount of Blue River water previously stored in South Platte reservoirs and subsequently released for municipal use in the Denver area. TABLE III - Return Flow of Colorado River Water This table presents the calculations to determine the percentage and amount of Colorado River water used by Denver that returns to the South Platte River through wastewater treatment plants. The table presents total monthly amounts of water delivered by Denver to its treated water and raw water customers during water year 1998. Also shown are monthly amounts of Moffat Tunnel water used from Column 8 of Table I and Blue River water used from Column 6 of Table II. The sum of these two gives the monthly totals of Colorado River water delivered by Denver to its treated and raw water customers. The percentage of Denver's water usage that is Colorado River water was calculated by dividing the amount of Colorado River water usage by the total water usage and appears in Column 5 of the table. Column 6 shows the monthly amounts of wastewater effluent base flow from Denver's customers. Base flow is the discharge of effluent during the months of December, January, and February. Utilizing data from these months minimizes or removes the effects of collection line infiltration from the effluent quantities. And, since water usage and, consequently, wastewater production is principally limited to inside uses in the winter and remains relatively constant throughout the year, the base flow amount can be assumed to be available throughout the year. The monthly totals of effluent base flow were then multiplied by the corresponding monthly percentage of Colorado River usage to yield the quantity of Colorado River water returned through the metropolitan area's wastewater systems. TABLE IV - Successive Use Operations Involvin~ Colorado River Water This table shows monthly totals, in acre-feet, for the 1998 water year for the successive use Denver made of its transmountain return flows. The figures reflect the . successive use of a portion ofthe return flow shown in Column (7) of Table III. Reported in Column (I) of this table is the amount of transmountain effluent exchanged to South Platte Reservoirs attributable to Colorado River water imported through the Roberts Tunnel and Cabin-Meadow Creek water imported through the Moffat Tunnel and used under contract by Denver. Column (2) shows the amount of water stored in Antero, Eleven Mile, and Cheesman Reservoirs equivalent to the evaporation losses from those reservoirs. This amount of water can be stored in those reservoirs pursuant to the April 12, 1989 decree in the "1940 Agreement" litigation (Case No. 8I-CW-405, Water Division 1). On February 25, 1991 the Colorado Supreme Court upheld the trial court's ruling that Denver's May I, 1940 agreement with members of Consolidated Ditches precludes Denver from reusing return flows from Colorado River water appropriated prior to May I, 1940. In lieu of not reusing this water, Denver is not required to make evaporation releases at Antero, Eleven Mile, and Cheesman Reservoirs. Since Denver is effectively replacing these evaporation