Laserfiche WebLink
Mr. Joe Kraig <br />Heit SWSP <br />September 22, 2015 <br />Page 2 of 5 <br />the construction bond that was posted for the slurry watt. The remaining bond of $197,280 <br />remains in place to cover the remainder of the reclamation plan. With the slurry wall <br />installed and approved by DWR as meeting the State Engineers lining criteria for gravel pit, <br />the Heit Mine is in compliance with the State Engineer's requirements pursuant to 5 37-90- <br />137(11). <br />Depletions <br />You have estimated that up to 2.0 acres of ground water surface will be exposed at <br />the Heit Pit in the settling ponds. Net evaporative depletions were calculated using a gross <br />annual evaporation of 44 inches from the exposed water surface, with a credit of 9.05 inches <br />for effective precipitation. The net depletion of ground water due to evaporation from the <br />2.0 acres of ground water exposed at the site was calculated to be 5.82 acre-feet. <br />The settling pond water is used onsite for washing aggregate and dust control. The <br />onsite production well, permit no. 66319-F (WDID 0205038), will also be used for dust <br />suppression and the washing of mined aggregate. You have estimated that a total of 1.0 <br />acre-foot of ground water will be used for dust control purposes at the site during this plan <br />period. You have projected washing up to 485,000 tons of mined aggregate a year. The <br />annual consumptive use for aggregate washing was estimated at 10.7 acre-feet using a <br />depletion factor of 3 percent by weight. There will be no concrete production at the Heit Pit <br />during this plan period. <br />The Glover method was used with to lag evaporative and operational depletions to the <br />South Platte River. The following parameters were used in the model: transmissivity (T) _ <br />140,000 gallons per day per foot, distance (X) from the surface of the exposed ground water <br />to the river = 2,750 feet for evaporation losses and 3,000 feet for operational losses, distance <br />(W) from the aquifer boundary through the exposed ground water to the river channel = <br />10,000 feet, and specific yield (SY) = 0.2. The location of the stream depletion is assumed to <br />be perpendicular to the river. Lagged depletions for this plan period will total 17.42 acre- <br />feet. <br />Replacements <br />The proposed source of replacement water for the Heit Pit is a total of 20.70 acre-feet <br />of fully consumable effluent leased from the City and County of Broomfield ("Broomfield"). <br />Of this amount, 20.46 acre-feet will be used for replacement purposes under this SWSP. The <br />existing lease was extended for a one-year period beginning September 1, 2015 and ending <br />August 31, 2016. The replacement water will be released from Broomfield's wastewater <br />treatment plant (WDID 0201021), which is located on Big Dry Creek approximately 29.75 miles <br />upstream from the Heit Sand and Gravel Mine. Of the 20.46 acre-feet of teased replacement <br />water from Broomfield, approximately 15% (3.04 acre-feet) will be lost during transit, based <br />on a transit loss of 0.5% per mile for the 29.75 miles from the Broomfield wastewater <br />treatment plant to the Heit Sand and Gravel Mine. The amount of Broomfield replacement <br />water that reaches the Heit Sand and Gravel Mine is 17.42 acre-feet, sufficient to cover the <br />projected lagged evaporative and operational depletions for this plan period. These transit <br />Loss amounts are subject to review and modification by the division engineer or water <br />commissioner. If a different transit loss is determined by the division engineer or water <br />commissioner the Applicant must modify their accounting and replacements, as necessary, to <br />be consistent with the determined transit loss. The monthly depletions and replacement <br />deliveries are found on the attached Table 3. <br />