Res 2013-124/Approving an agreement between the City and Espey Consultants, Inc. in connection with the Comprehensive Watershed Master Plan

Home Browse Search

SCOPE OF WORK The scope of work for this project has been divided into the following tasks: • Task 1: Data Collection • Task 2: Field Reconnaissance and Survey • Task 3: Hydrologic Analysis • Task 4: Hydraulic Analysis • Task 5: Storm Drain Analysis • Task 6: Rapid Creek Erosion Assessment • Task 7: Capital Improvement Plan • Task 8: Programmatic and Financial Analysis • Task 9: Reports and Meetings (Project Management) • Task 10: San Marcos Watershed Protection Program Management TASK 1: Data Collection To inventory storm water related issues in the City, this project includes a data collection effort consisting of Halff staff to locate and organize all available floodplain information. This collection will include all available Guadalupe - Blanco River Authority (GBRA), 2007 Flood Protection Plan (FPP), Federal Emergency Management (FETMA), City of San Marcos, Hays County and development information regarding streams within the San Marcos ETJ. TASK 2: Field Reconnaissance and Survey Halff will perform field reconnaissance to inspect problem areas, take photographs and collect measurements along study streams. 2.1 Problem Areas: Visit identified problem areas to assess source, gather notes, and take photographs. 2.2 Field Reconnaissance: Because field reconnaissance was performed in the GBRA and 2007 FPP studies, there are only a few locations where field reconnaissance is necessary. Field reconnaissance will be performed along all Type C stream and as needed along Type A and B streams. (9 structures) 2.3 Hydraulic Survey: Survey identified bridges and culverts as necessary for hydraulic modeling. — Types A and B — Structures along these streams will utilize the 2007 FPP surveys that were performed in 2007 with updates as needed under the GBRA project. — Type C — Since no recent surveys have been taken along these streams, new survey is requite along the streams to be studied using detailed methodology. A total of 4 structures and 3 cross sections will be surveyed. 2.4 Storm Drain Survey: Survey storm drain or other identified features not to exceed 10 days of work. TASK 3: HYDROLOGIC ANALYSIS Hydrologic analysis shall be conducted in accordance to FEMA and City of San Marcos guidelines and specifications. 3.1. Hydrologic Modeling: Develop new Hydrology using Snyder's UH approach for the existing and ultimate conditions 2 -, 5 -, 10 -, 25 -, 50 -, 100 -, 250 -, and 500 -year events. All approaches will be consistent with the GBRA methodology. Ultimate conditions will be based on the San Marcos Comprehensive plan. It should be noted that the GBRA methodology uses a Snyder's unit hydrograph approach. — Types A and C: The hydrology for these streams will be generated under the GBRA project. No new analysis is necessary. Page 3 of 10 ON HALFF`