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anticipated to be exposed by excavation, if it is exposed, excavation will cease at an elevation of <br /> 2 feet above the groundwater level. <br /> 4. Irrigation Water <br /> The land within and surrounding the permit area is not irrigated. <br /> 5. Water Consumption for the Operation <br /> The Hayden Gravel Pit is on an elevated terrace and there is no groundwater on the terrace. This <br /> is known from existing operations on the terrace further north of this site and also the lack of <br /> springs emanating from the base of the gravel anywhere on the site. There is very little moisture <br /> in the gravel that will evaporate when the material is mined. Table G-2 shows the total <br /> consumptive uses anticipated for this site. <br /> 5.1 Control dust on the haul roads and excavation areas <br /> Water used for dust suppression is usually 100 percent depletive with no measurable return <br /> flows to the river system. Dust from the haul roads will be controlled by paving for all areas <br /> outside the mining pit boundary. Water will be used on all in pit roads. Water will only be <br /> applied when needed at this elevation, since cold conditions on site for much of the year <br /> result in little evaporation and/or dust. The main access road will be graveled to reduce the <br /> water requirements. It is assumed that watering of roads will require 900 gallons water 4x per <br /> day for 100 days per year. Other days will have natural moisture on the roads or the site will be <br /> inactive since the annual production is not very high. This is equivalent to 1.10 acre feet per year. <br /> It is also assumed that additional amounts may be needed during very dry windy conditions <br /> during the mining operation. This use is expected to be 1.2 acre feet per year. Therefore,the total <br /> consumptive use for this category is 2.3 acre feet per year. <br /> 5_2 Crushing and Screening Plant Operations <br /> The crushing/screening plant uses roughly a gallon of water per ton of raw gravel. This equates <br /> to roughly 100,000 gallons per year, or 0.31 acre feet per year. <br /> Hayden Gravel Pit G-3 Greg l rwicki and Associates,PLLC <br /> May 2020 <br />