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Second Submittal <br /> shown in Figure 8,there is a small deposit of terrace sediments associated with an unnamed <br /> drainage to the north that are connected to the alluvial aquifer. This small alluvial extension <br /> is treated as a steady flux boundary because the mechanisms for flow into the conceptual <br /> model are dampened by the porous media flow in this alluvial extension. Flux rates are <br /> estimated to range between 1.9 and 4.5 acre-feet/day as shown in Appendix C. <br /> The eastern and western boundaries of the model are flux boundaries that vary in time. To <br /> represent this flux, constant head boundaries are used that are related to the stage in the <br /> river. <br /> Internal Boundaries <br /> Within the area of interest, several types of hydrologic boundaries exist related to <br /> groundwater flow. Old gravel ponds that have been sealed from interaction with the <br /> groundwater system have zero flux boundaries as groundwater flow through the seals is <br /> insignificantly small when compared to fluxes through the alluvial aquifer. Area ditches <br /> provide recharge and discharge opportunities for groundwater. Leakage rates can range <br /> from 10 to 25% of the flow in'the ditch. Un-sealed gravel lakes and active mining pits <br /> become discharge points for the'alluvial aquifer. Evaporation can be a significant sink in <br /> the summer when evaporation rates can reach up to 5.74 inches in the month of July <br /> (CDWR, 2011). While no large capacity pumping from wells is known to exist in the area, <br /> groundwater wells are documented sinks to groundwater in the area of interest. These <br /> range from 20 to 40 gpm. <br /> 2.3.2 Hydraulic Parameters <br /> Porosity/Storage Coefficient <br /> The storage coefficient dictates the amount of groundwater that moves in and out of the <br /> pore space as aquifer conditions change (e.g., pumping from a well or cessation of <br /> irrigation returns). Storage coefficients for the Cache la Poudre alluvium range from 15 to <br /> 25%. A typical value used in the LaPorte area is 20% (CDWR, 2017). <br /> Loveland Ready-Mix Concrete 11 Telesto Solutions,Inc. <br /> 20180112_gnmxIwataamdy_2.d.bnuaald . January2018 <br />