Tamarack Contract and Supporting Docs

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nn w nn�r l _. TL his J L -.. .. -.�.. .. - -,. .. L 2001 through June 21, 2001 was 4,aL i acre -fe et r his p uii p eu water went to three rech aueas with a total surface area of 14 acres All three areas have an SDF value of 60 days The evaporation rate was determined from the NCWCD Crook weather station with the total net evaporation from the 14 acres for January through June 2001 being 16 acre -feet The total net recharge was 4,811 acre -feet The pumping to recharge ended on June 21, 2001 when a river call occurred Wells Nos 1, 2, 3, 5, 6, 7, and 8 are all 300 feet from the edge of the river and Well Nos 4, 9, and 10 are all 600 feet from the edge of the river Table 4 shows the depletive effects on the river after the wells were turned off on June 21, 2001 Table 4 also shows the accretions to the river due to all prior recharge activities at Tamarack which began in February 1997 when dust Well No 1 was operating This depletion/accretion analysis was done with the same procedures as analysis for the previous Tamarack Substitute Water Supply Plans The balance (accretions minus depletions) column in Table 4 shows that post - pumping Water Year 2001 depletions of the ten wells at Tamarack are replaced for the remainder of the South Platte River Compact period to October 15, 2001, and therefore senior downstream water rights are not impacted by Tamarack operations The balance column in Table 4 are the excess accretions available for other augmentation purposes The above mentioned additional Tamarack Ranch State Wildlife Area features to be supplied by some combination of Wells 1 through 10 could have an evaporative surface area of up to 60 acres Based on average net pond evaporation rates from the NCWCD Crook weather station, the following compares the evaporation depletions from 60 acres to excess accretions (Balance column of Table 4) for Water Year 2001 Evap Depletions from 60 acres Excess accretions July 30 0 ac -ft 572 4 ac -ft August 243 3222 September 190 2098 Oct 1 -15 59 830 Totals 792 11874 The above comparison shows there are abundant excess accretions to replace evaporation depletions resulting from use of some of the ten Tamarack wells to supply additional water surface features The 79 2 acre -feet of depletions is only 7% of the available excess accretions (1,187 4 acre -feet) for July through October 15, 2001 This comparison supports the above request that any of the ten wells be allowed to operate during periods of river call because and so long as accretions exceed depletions and therefore no injury to senior water rights occurs The remaining 93% of excess accretions is leased to VASP alyd/ 1.SP VY CD for t h eir well augmentation heeds in the lower South Platte River As Table 4 illustrates, the most critical period to track accretions versus depletions is the days surrounding when the wells next to the river are turned off or on Accounting on a daily basis will direct actual operations to assure accretions exceed depletions If need be, wells will be shut off the appropriate number of days before a river call or be delayed being turned on to assure accretions always exceed depletions on a daily basis for critical periods 2