Project Fact Sheet - colorado.gov

1 Project fact Sheet Animas Watershed Phase 2 Flood Study Floodplain Mapping Coordinator, CWCB Thuy Patton, MPA, CFM O: 303-866-3441 x3230 Community Assistance Program Coordinator, CWCB Stephanie DiBetitto, CFM O: 303-866-3441 x3221 Project Manager/Engineer, AECOM Geoff Uhlemann, PE, CFM O: 303-796-4783 Project Manager/Engineer, AECOM Rigel Rucker, PE, CFM O: 575-545-1107 COMMON QUESTIONS REGARDING THE ANIMAS WATERSHED PHASE 2 FLOOD STUDY What is the Project ? The study will provide more accurate hazard data for flooding and related hazards (ice jamming, post-fire flooding, sediment-bulked flooding, etc.)

2 Once the study is complete, the Federal Emergency management Agency (FEMA) will likely use the data in their Risk Mapping, Analysis, and Planning Program (Risk MAP) to update Flood Insurance Rate Maps (FIRMs); however, a regulatory update is not funded at this time. This Project includes field reconnaissance, channel and overbank surveys; creating terrain models from updated topographic data; evaluating hydrology; hydraulic modeling; and flood hazard delineations. Field survey will be completed in the Spring/Summer of 2018 with and draft floodplains for community review in late 2018.

3 Why was it Initiated? The Project was initiated in 2018 by the colorado Water Conservation Board (CWCB) and Federal Emergency management Agency (FEMA) to meet needs that were identified in coordination with community officials, government agencies, and local initiatives during a Discovery Project (Phase 1) conducted in this area in 2016 & 2017. The updated hazard data can be used by communities and agencies for planning, permitting, and design decisions along with emergency response, infrastructure rebuilding, and private development and reconstruction.

4 Furthermore, the effective special flood hazard area (SHFA) delineations in the Project Area are often in excess of 30 years old and do not accurately reflect flood hazards. What is the Study Process? The study includes a science- and engineering-based approach to identify potential flood risk zones: Topographic data is obtained to determine ground elevation. This elevation information, obtained via aircraft, was acquired during various years between 2012 and 2016 throughout the study area, and provides a snapshot in time to conduct the study.

5 Survey data will be obtained in Spring/Summer 2018 to supplement the topographic information and to gain the necessary detail on bridges, culverts and the ground below the water line. Streams that will not show base flood elevations on FIRMs will not include survey. Hydrology uses historical stream flow data from gages and regional equations to determine predicted flow rates for select flood events. Hydraulic models are then built to simulate flow through rivers using topographic, survey, hydrologic, and ground-cover information. These models simulate river conditions and produce predicted water surface elevations anticipated during flood events.

6 These results are compared to known flood elevations of similar events to verify findings, if available. Predicted water surface elevations are mapped on work maps for review and use. These include calculated floodplain limits and other helpful information. Project fact Sheet Animas Watershed Phase 2 Flood Study Floodplain Mapping Coordinator, CWCB Thuy Patton, MPA, CFM O: 303-866-3441 x3230 Community Assistance Program Coordinator, CWCB Stephanie DiBetitto, CFM O: 303-866-3441 x3221 Project Manager/Engineer, AECOM Geoff Uhlemann, PE, CFM O: 303-796-4783 Project Manager/Engineer, AECOM Rigel Rucker, PE, CFM O.

7 575-545-1107 Since topographic data is a snapshot in time, local communities and counties have also been providing updated information for areas where there are multiple concurrent construction and/or recovery efforts happening. If it is possible within the Project timeline, updated information is incorporated into the modeling; if they are not captured, additional changes still can be made to these studies after the Project is finalized through FEMA s Letter of Map Change (LOMC) process. What are the Roles of Specific Stakeholders? The colorado Water Conservation Board (CWCB) is in charge of managing the Project and overseeing work being conducted.

8 CWCB partnered with AECOM, a nationally recognized firm, to complete this flood risk study. The Project team is also partnering with community officials to provide outreach support. FEMA is reviewing results and providing feedback. Ultimately, FEMA administers the NFIP and oversees any regulatory floodplain updates. If a regulatory update is funded at a later time, FEMA will use the final study results to update FIRMs. Local officials from counties and communities are being updated regularly on the progress of the study, and are given the opportunity to review draft results.

9 This will allow concerns to be communicated to CWCB before preliminary information is released for public review. Local officials are also being asked to identify public outreach opportunities so that homeowners and businesses can also see Project results. The data will ultimately be owned by community leaders as local administrators of the NFIP and they will communicate and adopt flood risk, manage development and construction, and enforce regulations. If a regulatory update is funded at a later time, property owners will have an opportunity to review results of the analysis prior to FIRMs being finalized.

10 The forum to view this information will vary depending on each community, so please contact your local floodplain administrator for more information. Who Approves these Changes? CWCB is working with FEMA to review results of the study throughout the process. Community officials are also being asked to review the results to avoid concerns when the results are released. At a later time, everyone is given an opportunity to review the maps when FEMA publishes them on preliminary FIRMs. After the preliminary FIRMS are released, FEMA will also initiate a statutory appeal period, where the new floodplains can be appealed using technical data.