2017-08-22_HYDROLOGY - M1981112 - Laserfiche WebLink

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Builder’s Aggregate SWSP August 18, 2017 Page 2 of 7 Evaporation The Applicant proposed to replace evaporation from exposed ground water at the site based upon evaporation atlases in NOAA Technical Report NWS 33 and the SEO monthly distribution factors for sites below 6,500 feet, as shown in attached Table 1. Gross annual evaporation at the gravel pit location is estimated to be 4.1 feet per year (49.2 inches). As shown in Table 2 (attached), there was no exposed ground water in April through June and therefore, the total evaporative depletions from the 3.45 acre area is 10.33 acre-feet through March 2018. The Applicant has elected not to claim any historical consumptive use credit for native vegetation against the gross evaporation amount. Mined Product The applicant plans to mine approximately 3,000 cubic yards of material during the plan approval period. The material is washed and was assumed to have 4 percent moisture content by weight. This results in 0.04 acre-feet of water removed with the mined material, as shown in Table 2. First Fill The applicant has estimated a volume of first fill that results in a depletion to the stream when mined material is removed, waste material fills part of the hole created by removal of material and groundwater fills the rest of the hole. The applicant assumed a porosity of 0.407, corresponding to the characteristics of the desired materials that are not returned to the hole. The volume of water in the first fill is estimated as 1.1 acre-feet. Replacement of Depletions During SWSP Approval Replacement supplies are provided from excess credits generated under the Riverside Irrigation District augmentation plans. BA has arranged for a 1 year trade related to shares of the Riverside Irrigation Company owned by BA. A copy of the water order with Riverside was provided with the SWSP request. The water order lists recharge credits from case number 02CW86 (WDID 0102522), but the Applicant’s engineer requested to use all excess recharge credits legally available through Riverside. Riverside’s representative 1 confirmed their willingness to apply any legally available excess credits to meet BA’s obligations. Riverside has access to recharge credits from several decrees in addition to 02CW86, but not all of the decrees allow the leasing of excess credits to others, and some of the decrees place limits on the length of time that a particular source may be leased. The following table describes Riverside’s recharge decrees and if credits from that particular decree may be used for BA’s replacement pursuant to this SWSP. 1 Don Chapman phone call with Tracy Kosloff on August 8, 2017.