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b. Surface Water Effects and Mitigation <br />Drainage and sediment control measures implemented by the applicant are <br />sufficient to ensure that the quality of water downstream from the site is not <br />impacted. The only impact on water quantity is the consumptive use of <br />approximately 6 acre -feet per year. <br />The Terror Creek Loadout withdraws water from two sources. Water for dust <br />suppression is supplied by senior water rights from the Deer Trail Ditch. The <br />ditch withdraws water from Hubbard Creek. Use averages 5,000 gallons per <br />day (5.6 acre - feet /year). Previously, this water was used to irrigate orchards <br />where the loadout is now located. A domestic well which supplies about 450 <br />gallons per day (0.5 acre- feet/year) is used for domestic use at the Loadout <br />office and bathhouse. Terror Creek's consumption amounts to 0.002% of the <br />North Fork's mean annual yield at Somerset. This amount of consumption is <br />considered by the Division to be insignificant. <br />Upon final reclamation, the essential hydrologic functions of the site will be <br />restored. The essential hydrologic function which must be restored within the <br />affected area is the capability of the site to support flood irrigated agricultural <br />production levels comparable to pre - disturbance levels. The major <br />components of the reclamation plan which will ensure that this essential <br />hydrologic function is restored are the following: <br />Regrading of the loadout pad and diversion structures to <br />approximate original contour so as to allow for distribution of <br />irrigation water as was practiced prior to disturbance. <br />Scarification and ripping of the regraded slope so as to relieve <br />compaction and allow for root penetration and aeration. <br />Replacement of a sufficient depth of a plant growth medium so as <br />to provide for a water holding capacity within the rooting zone that <br />will support irrigated agricultural productivity comparable to <br />pre - disturbance levels. <br />Soil physical data and analyses supplied by the applicant for topsoil, subsoil <br />and colluvium indicate that available water at field capacity would vary from <br />3.41 inches to 4.81 inches within the identified rooting zone (44 inch depth) in <br />orchard land immediately adjacent to the disturbed area. The analyses indicate <br />that the physical characteristics and water holding capacity for the colluvial <br />deposit are consistent throughout its entire depth. Thus mixing of the material <br />as a result of construction and reclamation would not reduce water - holding <br />capacity. <br />Assuming that 10.9 acres of disturbed land will be retopsoiled, and that there <br />are 5,243 cubic yards of stockpiled topsoil and 15,206 cubic yards of subsoil <br />suitable as a plant growth medium, the total soil layer would be 14 inches in <br />depth. This compares favorably with the 13 -inch depth which existed prior to <br />disturbance. The water holding capacity of the reclaimed land would be <br />comparable to orchard soils adjacent to the permit area. <br />17 <br />