Laserfiche WebLink
Ready Mix Concrete Substitute Water Supply Plan <br /> February 13, 2020 <br /> Page 3 of 10 <br /> prevent the exposure of groundwater. The current bond amount for the new <br /> Morton-Holton Lakes site is $4,150,000.00. <br /> Depletions <br /> The projected depletions for Stages 1, 2, 6A, 6B, 3, 4, 5 and 6C/6D are resulting from <br /> evaporation, water washed for the mined product, dust control, water for slurry wall <br /> construction, and the refill of Stage 1. The Applicant proposed to replace evaporation <br /> from exposed ground water at the Morton-Holton site based upon evaporation atlases in <br /> NOAA Technical Report NWS 33 and the SEO monthly distribution factors for sites below <br /> 6,500 feet, as shown in attached Table 1. Gross annual evaporation at these gravel pit <br /> locations is estimated to be 44.27 inches per year. Net evaporation is defined as gross <br /> evaporation less the consumptive use of water by vegetation that naturally occurred at <br /> the site prior to construction of the pit. The historical consumptive use was assumed to <br /> be equal to the effective precipitation, which was estimated based on the data from the <br /> Fort Lupton 2SE (ID 3027, record 1950-1976) and Brighton 1 NE (ID 950, record 1976-2014) <br /> NOAA weather stations. The net evaporation rate for the exposed water surface is <br /> estimated to be 2.92 acre-feet/acre, as shown on the attached Table 1. <br /> The projected maximum exposed ground water surface area at each stage is described <br /> below. <br /> Stage 1-As described above the exposed groundwater surface area in the southern <br /> portion of Stage 1 is projected to be 11 acres in January, 2 acres in February and 11 acres <br /> for the remainder of 2020. <br /> Stage 2 - Stage 2 currently exposes 12.5 acres excavated at a depth of 20 feet. As <br /> described above the exposed groundwater surface area in Stage 2 is projected to be 12.5 <br /> acres for January and February, 7 acres in March and 5 acres for the remainder of 2020. <br /> The Applicant plans to refill Stage 2 in 2021 or sooner if free river conditions allow in late <br /> 2020. <br /> Stage 6A - Mining at Stage 6A is completed. The exposed groundwater surface area <br /> will remain at 0.1 acre through the end of December 2020. Stage 6A will remain <br /> dewatered throughout the SWSP approval period. <br /> Stage 6B - Stage 6B currently exposes 2 acres of groundwater and the exposed <br /> groundwater surface area is expected to decrease to 1.0 acre by July 2020, which will <br /> remain throughout the period of this SWSP. Stage 6B will continued to be dewatered <br /> throughout the period of this SWSP. <br /> Stage 3 - Stage 3 was backfilled with overburden from other stages at the end of <br /> 2019 and therefore there is no permanent surface areas or first fill depletions. <br /> Stage 4 - RMCC constructed a slurry wall around Stage 4. The groundwater <br /> surface area at Stage 4 is currently 0.5 acre and will remain at 0.5 acre through the end of <br />