Laserfiche WebLink
CENTER STREET AREA FRAMEWORK + POLICY PLAN <br />Stormwater Management System Project Elements <br />Rainfall Event <br />1" Event <br />Rainfall Depth <br />(IN) <br />1.00 <br />Runoff <br />Volume (CF) <br />5,500 <br />Runoff <br />Volume (GA) <br />41,140 <br />1-Year <br />2.46 <br />109,956 <br />14,700 <br />2-Year <br />2.86 <br />17,600 <br />131,648 <br />5-Year <br />3.58 <br />22,700 <br />169,796 <br />10-Year <br />4.26 <br />27,500 <br />205,700 <br />Table 1: Summary of expected runoff volumes. <br />Additional Considerations <br />A simplified estimate of stormwater runoff expected <br />from the street section was assembled to ensure the <br />watershed can produce enough runoff to adequately <br />fill the tanks. Table 1 is a summary of expected <br />runoff volumes for a variety of events. A rainfall event <br />producing between 3.6 and 4.3 inches in 24 hours <br />(5-year to IO-year return interval) can completely fill <br />the tank. <br />During final design, additional hydraulic information <br />will be provided to provide an effective high flow <br />bypass system. In other words, if the tank is full and <br />the City experiences a 100-year rainfall event, there <br />will be adequate bypass capacity to reduce local <br />to rains: <br />n..Mr�. avnnarycrs+stmm+sewer r,.,In�.,,,�.. <br />• <br />Storm Serer %Wee Mein° <br />flooding and protect the tank(s). Also, since the COR <br />trunk storm sewer system is already designed to <br />accommodate a 100-year rainfall event with discharge <br />to regional flood storage areas, the bypass system <br />will effectively mimic the originally designed scenario. <br />In between events when irrigation is occurring, or <br />the tanks is being filled, there will be hydraulic relief <br />on the trunk system and volume control provided. <br />Since the reuse water will pass through a filter and <br />potentially other treatment methods, the impact to <br />groundwater resources through the infiltration of <br />irrigation water is expected to be very minimal. <br />Impacts to groundwater resources in the Downtown <br />District are not anticipated. <br />0Smrry <br />29 <br />