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mowed grass up near trails by the road. If additional storage is needed, these cells <br />could be changed to contain ponds of the needed size. <br />Following the development of a drainage system, detailed modeling was done for the <br />individual blocks within the RTC site, and combined with the model output for the areas <br />draining into the site from the north and northwest. All of this drainage was then routed <br />through the site, into the stormwater handling facilities south of the site, and through the <br />proposed drainage corridor to the Mississippi River. <br />Two modeling scenarios were run to bracket a range of flow under maximum and <br />minimum conditions. The first run of the XP-SWMM quantity modeling developed <br />traditional runoff estimates for the 100-year design event with no infiltration occurring on <br />site. This "maximum runoff condition" is contained in Table 17.2. <br />In the second scenario, a factor was incorporated into the model on a block -by -block <br />basis to account for some infiltration under small-scale events, reflective of the sandy <br />soils inherent to the site. Infiltration is not a design element for the 100-year event, but <br />rather used to estimate volume and rate reductions during frequently occurring events. <br />Infiltration features will be considered during the design phase, but are not proposed as <br />part of this evaluation. However, to demonstrate the effect of infiltration on the 100-year <br />event, Table 17.3 contains the results of the "minimum runoff condition". <br />17-7 <br />