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Phase I South Drain Outlet -discharges into the west drainage swale above the 100yr local <br />storm discharge water surface elevation. The outlet is not expected to undergo <br />submergence and will perform as designed under 10yr-100yr storm events. <br />Phase II West Drain Outlet -discharges into the west drainage swale above the 100yr local <br />storm discharge water surface elevation. The outlet is not expected to undergo <br />submergence and will perform as designed under 10yr-100yr storm events. <br />Phase II East Drain Outlet -discharges into the east drainage swale above the 10yr local . <br />storm discharge water surface elevation, but below the 100yr local storm discharge water <br />surface elevation. The outlet is expected to undergo submergence for less than 1 hour <br />during a 100yr local storm event. Under submergence conditions the drain is not expected <br />to function at its designed capacity, however due to the short duration of outlet <br />submergence, it is not expected that groundwater mounding will have a chance to develop. <br />For Big Thompson River Flood Events; <br />All drain outlets are expected to undergo submergence during the 10yr, 50yr and 100yr river <br />flood events. The duration of flood peaks (taken from enclosed hydrograph) under which <br />the outlets are expected to undergo submergence are as follows: <br />10 yr - 2-3 hours <br />50 yr - 4-5 hours <br />100 yr - 8-9 hours <br />Under submergence conditions the drain is not expected to function at its designed capacity, <br />however due to the short duration of outlet submergence, it is not expected that <br />groundwater mounding will have a chance to develop. <br />c) To ensure that the drain is functioning properly, piezometers have been added to Exhibit <br />C-2 will and monitored monthly for 3 years following completion of each phase's slurry wall <br />and drain installations to verify that the predicted groundwater impacts have been <br />sufficiently mitigated. <br />6.4.12 EXHIBIT L -Reclamation Costs <br />10. Exhibit L now contains comprehensive itemized reclamation costs by phase of the <br />operation. <br />6.4.19 EXHIBIT S -Permanent Man-made Structures <br />11. Originally only Weld County was specifically notified regarding County Line Road as they <br />are responsible for maintenance of the structure. A letter and a structure agreement have <br />been sent to Larimer County Engineering for the same structure. Once their response is <br />received, it will be forwarded to the DRMS. If an agreement is not reached, a geotechnical <br />~hapg stability analysis will be provided demonstrating adequate structure protection. <br />Page 3 of 4 <br />