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Mr. Rick Parsons, P.E. February 10, 2016
<br /> L.G. Everist Combined SWSP
<br /> Page 5 of 14
<br /> to the water table. According to the "General Guidelines for Substitute water Supply Plans for Sand
<br /> and Gravel Pits" the product moisture loss is calculated as four percent by weight of mine material
<br /> excavated below the ground water table and two percent by weight for the mined material excavated
<br /> above water table. The Applicant anticipates 2016 mining production at the Carbon Valley Resource,
<br /> Rinn Valley Pit, Firestone Pit and Fort Lupton Sand and Gravel to be 200,000 tons, 380,000 tons,
<br /> 1,200,000 tons and 1,600,000 tons respectively. For 2017, production at these same sites is
<br /> anticipated to be 128,000 tons, 0 tons, 1,200,000 and 1,600,000 tons, respectively.
<br /> Water used for dust control at Carbon Valley Pit, Rinn Valley Pit, and Firestone Pit will come
<br /> from water originally pumped from the pits for dewatering. Water used for dust control at the Fort
<br /> Lupton Sand and Gravel was previously used from an existing alluvial well, permit no. 57957-F (WDID
<br /> 0205018 DI TIRRO WELL 2), located outside of the approved slurry wall on the Fort Lupton Pit site.
<br /> Well permit no. 57957-F is no longer being used for dust control, as Everist has a re-circulating water
<br /> system at the site where reusable water is pumped from lined cells to wash material and for dust
<br /> control.
<br /> Continuous dewatering operations at Carbon Valley Pit, Rinn Valley Pit, and Firestone Pit are
<br /> occurring in order to facilitate dry mining conditions. This water is used for dust control at these pits,
<br /> and is used for concrete production at the Rinn Valley pit. All other water pumped for dewatering is
<br /> returned immediately to the river system. The applicant has performed a lagged water balance for
<br /> these operations and account for the lagged depletions which is offset by monthly net accretions.
<br /> Totalizing flow meters have been installed and monthly meter readings showing dewatering volumes
<br /> were reported on the 2014-2015 submitted accounting.
<br /> A stream depletion model using the Glover method was used to calculate the lagged depletions
<br /> to the River. The alluvial aquifer model uses four aquifer input parameters for each site as follows: 1)
<br /> X-distance from centroid of the well to the river, 2) W-distance from the aquifer boundary through the
<br /> well to the river channel, 3) T-transmissivity of the alluvial aquifer (in gallons per foot/day) between
<br /> the well and the river, and 4) S-specific yield. The following parameters for each site listed in the
<br /> table below were used in the model:
<br /> TABLE E - AQUIFER CHARACTERISTICS
<br /> Site Name T X W S
<br /> Carbon Valley Pit 50,000 2,000 4,173 0.2
<br /> Rinn Valley Pit 125,000 715 4,173 0.2
<br /> Firestone Pit 72,300 2,210 2,262 0.2
<br /> Fort Lupton Pit 90,000 300 to 1,200 4,500 to 7,996 0.2
<br /> Star Water 120,000 558 4,300 0.2
<br /> Resources
<br /> Replacements
<br /> Saint Vrain Creek
<br /> L. G. Everist owns 8.45 shares of the Rural Ditch Company. Of the 8.45 shares of the Rural
<br /> Ditch (WDID 0600551) water, 1.41 shares will be available for replacement in this SWSP for 2016 and
<br /> 2017. On January 15, 2016 you submitted a historical consumptive use ("HCU") analysis. The 1.0 Rural
<br /> Ditch share previously included in the SWSP associated with the Rinn Valley Pit was removed from the
<br /> plan. However this SWSP will make replacement of the remaining return flow obligations (January
<br /> through April) from the use of the 1.0 Rural Ditch share associated with the Rinn Valley Pit in the
<br /> previous SWSP (see Table 16).
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