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HomeMy WebLinkAboutIR 8597 INFORMAL REPORT TO CITY COUNCIL MEMBERS No. 8597 To the Mayor and Members of the City Council May 18, 2004 4 ax TZ SUBJECT: Flood Hazard Assessment 1673 The April 30, 2004 storm was the third flash flood event within four years that has resulted in a tragic loss of life by drowning. The attached report outlines immediate, short term, and mid term actions the Transportation and Public Works Department is undertaking to review the City of Fort Worth's flood hazards. For some perspective, the following information gives some perspective to the magnitude of the city's stormwater concerns: • Over 5,600 properties in Fort Worth are located in the Federal Emergency Management Agency (FEMA) mapped floodplain areas. • Over $300 million in drainage capital improvement needs have been identified. • Over 130 roadway locations are periodically overtopped by stormwater, of which 32 have been identified as high priority. The City of Fort Worth has responded to these needs by undertaking capital improvements, reviewing and inspecting new construction to minimize future stormwater runoff, providing 24/7 emergency services, and by installing warning devices at known roadway flooding locations. The City recently implemented a *demonstration project where automated warning flashers were installed at three roadway locations. The -004 bond allocated $14.8 million for watershed planning studies and storm water capital improvements ""including the expansion of the automated warning system. The attached report further details actions that the City of Fort Worth will take to continue to protect lives and property from serious flooding dangers. ary W. Jack n City Manager Attachment rr ISSUED BY THE CITY MANAGER FORT WORTH, TEXAS TRANSPORATION AND PUBLIC WORKS Flood Hazard Assessment and Emergency Response Programs May 18, 2004 FORTWORT14 The April 30, 2004 storm was the third flash flood event in Fort Worth within the last four years that has resulted in loss of lives. The following facts provide information regarding the City's flood hazards. • Over 5,600 properties in Fort Worth are located in FEMA mapped floodplain areas. • Over $300 million in drainage capital improvement needs have been identified. • Over 130 roadway locations are periodically overtopped by flood, of which 32 . have been identified as high priority. The City of Fort Worth has responded to these needs by undertaking capital improvements, reviewing and inspecting new construction to minimize future stormwater runoff, providing 2417 emergency services, and by installing warning devices at known roadway flooding locations. The City recently implemented a demonstration project where automated warning flashers were installed at three roadway locations. The 2004 bond allocated $14.8 million for watershed planning studies and storm water capital improvements including the expansion of the automated warning system. City staff will undertake a broad review of our Flood Hazard Assessment and Emergency Response Programs to ensure that we are spending our limited resources effectively to reduce storm water hazards and respond to emergencies as proactively as possible. Both these programs are already in place; each will be reviewed in detail. The following action plans are already underway. 1 of 4 Flood Hazard Assessment and Emergency Response Programs Immediate Actions • Butler-McClure Flood Hazard Action Plan 1. REPAIR/ENHANCE TRAFFIC SIGNS Scope: Replace and/or repair all STOP signs, High Water warning signs, and storm gauges damaged at site. Add High Water warning sign between Butler and McClure culverts for eastbound and westbound traffic on Butler. Completion Date: Completed 2. REPAIR ROADS AND DRAINAGE INFRASTRUCTURE Scope: The McClure culvert will be repaired by removing and re-setting portion of culvert pipes,extending and repairing headwalls,placing flowable fill in voids,and repairing roadbed and pavement. Culvert headwalls on Butler will be repaired. Scour holes will be filled and sediment, debris, and tree snags will be removed to improve flow. Completion Date: June 4,2004 • City-wide 3. REVIEW ALL CRITICAL LOW WATER CROSSINGS(32 crossings) Scope: Replace and/or repair all,High Water warning signs,and storm gauges at sites. Completion Date: Completed Short-term Actions • Butler-McClure Flood Hazard Action Plan 1. AUTOMATED HIGH WATER WARNING FLASHERS Scope: A warning system will be installed to automatically warn traffic by flashing lights whenever roads in the area are over-topped by a storm. Completion Date: November 2004 2. COMPLETE WATERSHED STUDY Scope: Consultant has been retained to study flooding conditions in the Fair Park Channel(SC-5)between 1-35 and Sycamore Creek. Alternative treatments and costs will be developed for addressing these problems as part of long-term capital improvement program. Completion Date: August 2004 • City-wide 1. Develop Public Education Program. In cooperation with the Public Information Office, public education programs of the National Weather Service (NWS) and other cities would be reviewed and used as a basis for developing"best practices"to use for a similar program in Fort Worth. 2. Review locations where flooding historically occurs and evaluate existing prioritization of the most critical crossings. 3. Re-evaluate design standards and criteria to determine when and where warning devices should be used for the various types of roadway flooding hazards. Detailed checklists for maintaining each type of warning device, procedures defining frequency and responsibility of maintenance, and records keeping will be developed. 4. Review emergency response policy/practice to determine how personnel can be deployed during a storm event to best protect the public. 2 of 4 Flood Hazard Assessment and Emergency Response Programs Mid-term Actions ❑ Butler McClure Flood Hazard Action Plan 1. PHASED ROADWAY/DRAINAGE UVIPROVENIENTS Scope: It is anticipated that short-term improvements can be made to the existing culverts as part of a phased implementation plan to be developed in the watershed study cited above. $150,000 has been earmarked for these improvements under the 2004 CIP Minor Drainage Program. Staff will also evaluate opportunities for making complementary improvements to general road conditions in the immediate vicinity of the two culverts. Completion Date: March 2005 • City-wide—(see detailed work program below) 1. Review/re-evaluate all hazardous crossings in the City. 2. Compile engineering data for each flood location. 3. Evaluate Design Standards and Treatments. 4. Determine Priorities. 5. Prioritize Locations for High Water Warning System expansion. 6. Propose funding prioritization for storm water capital improvements to maximize public safety using available fmancial resources. Products rr Three documents will be prepared: e Flood Hazard Inventory—Data compiled for each flood-prone roadway location will be preserved for continuing reference in several large three ring binders. This will include engineering design information, hydrologic and hydraulic data, aerial and floodplain mapping, assessment of flood hazard, priority, recommended design treatment, and layout sketches. • Watershed Assessments Report—Rather than focusing on discrete locations on the public street system, this report will summarize topographic and flood plain data on a watershed-by-watershed basis. The purpose of this report will be to summarize the extent and severity of flooding hazards in each watershed, as well as the priority and approximate scope and cost of capital improvements to correct these problems. • Summary Report—This report will briefly summarize the findings and recommendations of the study in a format suitable for briefing the City Council. The focus of the report will be to describe a broad overview of flooding problems in Fort Worth and their severity, along with recommendations for mitigating these hazards. Scheduled for completion in December 2004. o 3 of 4 Flood Hazard Assessment and Emergency Response programs Detailed Work:Program The scope of the work is summarized below: • Develop Public Education Program: In cooperation with the Public Information Office, public educations programs of the National Weather Service (NWS) and other cities would be reviewed and used as a basis for developing a similar program for Fort Worth. Water bill mailers are envisioned as an effective way to increase public awareness and to obtain citizen input on where flooding has occurred. Town hall meetings and outreach efforts to high school drivers education programs will also be considered. • Review/re-evaluate all hazardous crossings in the City: Existing documents will be reviewed to identify street locations subject to periodic flooding. These documents include the inventory of flood-prone structures within fort Worth, the Hazard Mitigation Action Plan (HazMAP) recently completed NCTCOG, floodplain maps and data compiled by FEMA, and historical records of flooding contained in City's drainage and citizen request files. • Compile engineering data for each flood location: Existing GIS data will be compiled for each crossing, including structure dimensions and photographs of the structure and roadway. These will be supplemented as needed for recently annexed areas. FEMA data and topographical maps will be analyzed along major streams to determine flow depth and velocity for various flood events. Site visits will be used to verify data, including flood profiles and the elevations of roadway and nearby private structures. • Evaluate Design Standards and Treatments: Roadway and traffic control design standards will be reviewed, including those used in other cities, to make sure that they effectively respond to public safety needs. Standard treatments will be developed for application to various categories of hazard. • Determine Priorities: The extent and severity of flooding hazard will be assessed at each site previously identified, based upon established criteria, which will in turn identify the type of treatment that will be used. • Prioritize Locations for High Water Warning System expansion: The 2004 CIP provides $500,000 for expanding the automated High Water Warning System, which should be sufficient to fund 10 to 12 sites. This study will develop a prioritized list of locations for these devices based upon hazard, and develop a layout sketch plan and control data for each site selected. Scheduled for completion in August 2004. 4 of 4 ...................