Laserfiche WebLink
City Council Meeting Minutes June 14, 2019 <br />Atlas 14, and receive a Storm Water Utility Update; and provide direction to Staff. <br />John Espinoza, Project Engineer, led the presentation regarding Atlas 14 which <br />relates to rainfall and how we use it. Some uses include the following: <br />Design Infrastructure <br />— Storm drains / inlets <br />— Open channels <br />— Detention systems <br />— Bridges / culverts <br />Basis for <br />— Floodplain Regulations <br />— Design Criteria <br />— Hydrologic & Hydraulic Analysis <br />There have been increases in rain events that have impacted our region. Mr. <br />Espinoza explained the change in frequency, the annual chance probability, <br />and the average 24-hour precipitation depths. With more rainfall there will be <br />a requirement for larger infrastructure which effects private development, <br />Public/Capital Improvement Projects. Floodplain maps will expand and more <br />homes and businesses will be at risk than previously thought. Regulations and <br />Criteria will require updates. <br />Mr. Espinoza explained there is a Central Texas Atlas 14 Group that meets <br />monthly to share efforts. This group consists of the following entities: <br />City of Austin, City of San Marcos, City of San Antonio, City of Georgetown, <br />Hays County, Travis County, Williamson County, and Texas Department of <br />Transportation. <br />San Marcos will make the following considerations: <br />-FEMA Floodplain maps <br />— New version to be released in Summer 2020 <br />— New maps will not reflect Atlas 14 rainfall <br />— To update, will require revised H&H models, mapping and Federal <br />Emergency Management Agency (FEMA) approval process <br />— Coordination with FEMA and United States Army Corp of Engineers <br />• Changes to City ordinances and design criteria <br />• Changes to CIP projects <br />The city has done hydrological testing that have presented preliminary results <br />indicating flow increases in riverine and non-riverine areas. The City will <br />update design criteria to reflect Atlas 14 and further evaluation will be needed <br />City of San Marcos Page 2 <br />