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The Blanco Gardens north side storm sewer system drains Bugg Lane <br />and River Road with odual 4B -inch outfall tothe Blanco River. The Blanco Gardens mouth side <br />system drains tomn outfall on the San K8aropo River. The current storm water infrastructure is not <br />adequate to address drainage issues from local rain events and will he upgraded with two other <br />CDBG-DRprojeote. <br />The Blanco Gardens area is influenced by the Blanco River overflows. The <br />B|enon Gardens and Clarewood/Barbara Drive projects Will upgrade the storm sewer system to <br />provide capacity for local storm events. However, the infrastructure which would be required to <br />convey the overflow from the Blanco River would be too large to construct within the existing <br />neighborhood. <br />:COBG-URfunds will beused for land acquisition tosupport this project. <br />This project will make bank improvements toblock low bank areas inthe Blanco River ovedzonk <br />which allow the overflow to occur. With the improvements, the Blanco Gardens area can gain <br />protection from approximately 3-4 feet of river rise. The bank improvements would have the <br />purpose of setting maximum grade |imitotiona, minimum widths and surface. It is possible that <br />the improvements could also provide a dual purpose of a greenway if desired by the community. <br />The blockage of diversion flow will cause n minor rise in water surface elevation. To address this <br />minor rima, this project will also include flow capacity improvements to the Blanco River. These <br />capacity improvements could include modifications to the channel and/or an overflow channel on <br />the opposite bank. <br />The project benefit will reduce the risk for flooding to the Blanco Gardens neighborhood <br />by 44% annually by reducing the level of floods from overtopping the bank from m 20 -yr or higher <br />floods to m 36 -yr or higher. And during higher floods the Omm and depth ofwater will be reduced. <br />The graphic below illustrates the additional protection based upon previous flood events. <br />�160,000 <br />�140,OOn <br />�120,000 <br />� <br />C u`0,nnv <br />M <br />� <br />' vv'mm <br />60,000 <br />� *o'mm <br />0. <br />Historic Flood Events - Blanco River <br />May Oct. Oct. Oct. May Nov. Apr. Jun. Feb. Oct. Dec. mac mu Sep. Nov. <br />Date of Historic Flood Event <br />National Obliective: Low Moderate Income <br />p. 285 of the electronic document <br />