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SPDSS Task 4 Memorandum <br />November 23, 2004 <br />• The City of Aurora Utilities Department provided monthly electronic records <br />back though 1989 and provided access to monthly operational records on paper <br />back to 1971. <br />• Daily and monthly continuously monitored streamflow data for Homestake <br />Pipeline deliveries upstream of Eleven Mile Reservoir (Station 07086300) are <br />available for portions of 1980, 1981, and 1982. This data varies significantly <br />from the data provided by the City of Aurora. Because of the short period of <br />record for this Station, the incomplete data, and the significant difference between <br />this source and the more complete data set provided by Aurora, this data was not <br />used in the creation of the StateMod format data file for Homestake Pipeline. <br />• Daily and monthly continuously monitored streamflow data for Station <br />HOMSPICO upstream of Spinney Mountain Reservoir are available from 1989 <br />through present. <br />• Based on information provided by Aurora, it was learned that Aurora did not use <br />Homestake Pipeline extensively between 1967 and 1970 because of financial <br />difficulties. In a March 23, 1970 memo from C.A. Wemlinger to the City of <br />Aurora, discovered in the City of Aurora files, an annual value was reported for <br />1969 of 2,718 acre-feet annual diversions. Based on the distribution of diversions <br />in 1971, 1972, and 1973 the diversions for 1967 through 1970 were estimated at <br />an annual diversion level of 2,500 acre-feet distributed as 1,000 acre-feet in July <br />and August, 200 acre-feet in September and March, and 100 acre-feet in April. <br />• As a result of the variety of diversion data sources available a StateMod format <br />data file (HOMSPICOfilled. stm) was created for Homestake Pipeline. <br />• For future data acquisition, the recommended source for Homestake Pipeline <br />diversion records is the continuously monitored data at Station HOMSPICO. <br />Berthoud Pass Ditch <br />• Continuously monitored Station 09021500 represents a complete set of diversion <br />data for the SPDSS study period and is the preferred source for historical and <br />future diversion data for Berthoud Pass Ditch. <br />Boreas Pass Ditch <br />• Administrative records for Boreas Pass diversion at Structures 2304611 and <br />3604685 are inconsistent, with differences ranging from 0 to 68 percent. The <br />reason for these inconsistencies is unknown. <br />• Diversion records provided by the City of Englewood are similar to but not the <br />same as continuously monitored streamflow data for Station 09046000. <br />Discrepancies between the City of Englewood diversion data and Station <br />00046000 were identified in the early 1990s. Possible reasons for these <br />discrepancies may include revisions to Boreas Pass Ditch including the <br />installation of a new flume. When installed, it was understood that the new flume <br />for Boreas Pass Ditch was a 2-foot Parshall flume, however, upon inspection by <br />Division 1 Hydrographer Bob Cooper, he found that the new flume was an 18 <br />inch flume, not a 2-foot flume. If applied, use of incorrect rating tables for <br />Page 10 of 19 <br />