The Iowa Watershed Approach

Transcription

1 Larry Weber Director, IIHR Hydroscience & Engineering 1

2 North Kickoff Raccoon meeting River follow-up Watershed Project Update 2

3 Review: National Disaster Resilience Competition Funder: US Dept. of Housing and Urban Development, in collaboration with the Rockefeller Foundation Funding level: $1B; CDBG; Superstorm Sandy Applicant: State of Iowa, Iowa Economic Development Authority (IEDA) Iowa Watershed Approach program developed by IFC in consultation with many, many partners Iowa award: $96,887,177 (fourth largest award behind Virginia, New York City, and New Orleans) 3

4 Review: NDRC Qualifications Presidential Declared Major Disaster in 2011, 2012, or 2013 Benefit to low to moderate income (LMI) areas Environmental and/or infrastructure most impacted and distressed and unmet recovery needs areas (MID-URN) present 4

5 Review: IWA Goals Reduce flood risk Improve water quality Increase resilience Engage stakeholders through collaboration and outreach/education Improve quality of life and health, especially for vulnerable populations Develop a program that is replicable throughout the Midwest and the United States 5

6 Review: IWA Project Description Built of the framework of the IWP Establish a WMA Develop a hydrologic assessment and watershed plan Deploy monitoring equipment Work with project coordinators and volunteer landowners to implement projects that reduce the magnitude of downstream flooding and improve water quality Assess project benefits based on monitoring data and modeling 6

7 Kickoff meeting follow-up 7

8 Previous Kickoff meeting Meeting follow-up IWA website launched ( Flooding trends Modeling introduction BMP mapping inventory ACPF tool 8

9 Project Update Overview IWA Program Timeline Hydrologic Assessment Hydrologic Model Development Review Hydrologic Model Updates Radar Rainfall Estimate Inputs to Model Initial Hydrologic Model Results Sensor Deployment 9

10 Kickoff IWA Program meeting Timeline follow-up 10

11 Hydrologic Assessment Develop and run watershed-scale hydrologic models (HEC-HMS) to estimate watershed responses to rainfall events Modeler breaks the watershed down into manageable and representative user defined areas (called subbasins) Simulate hydrologic processes using a mathematical approach Compare simulated results to observed streamflow (where known) to assess model performance Documentation

12 Hydrologic Model Development Review Approximately 2470 square miles Subbasins Delineated

13 Hydrologic Model Development Updates Watershed breakdown includes: Lake/Reservoir Outlets that Regulate Discharge Known Discharge (or Stage) Measurement Locations - United States Geologic Survey (USGS) Points of Interest North Raccoon HEC-HMS Model: Subbasin Delineation Refined Increased to 1154 Subbasins Delineated Average of approx. 2.1 square miles IFC has obtained stage-storage-discharge relationships for: Storm Lake Black Hawk Lake Twin Lakes

14 Hydrologic Model Development Updates North Raccoon + South Raccoon Watershed To get discharges in the Raccoon River coming into the Des Moines area, IFC will also simulate discharge in the South Raccoon Watershed (inflow near Van Meter) North Raccoon HEC-HMS Model: 1154 Subbasins Delineated South Raccoon HEC-HMS Model: 417 Subbasins Delineated

15 Model Calibration Rain Events Using radar rainfall estimates from past storms as rainfall input to drive the hydrologic modelling Stage IV Radar Rainfall Product produced by National Weather Service (NWS) Available February 2002 Present Increased accuracy for rainfall location and timing

16 Model Calibration Rain Events Storm Lake Jefferson May 25 June 1, everywhere in both North and South Raccoon Watersheds Highest Local Totals 5 6 around Storm Lake ~4.5 in 36 hours, May 26th & 27th near Jefferson ~5 in 36 hours, May 26th & 27th

17 Rainfall Animation May 25 th June 1 st, 2013

18 Model Calibration Rain Events Sac City May 25 June 1, everywhere in both North and South Raccoon Watersheds Highest Local Totals 5 6 around Storm Lake near Jefferson Jefferson Peak Discharges Sac City 5/28/2013 7,510 cfs {Max at site 3/23/ ,100 cfs} Jefferson 5/30/ ,800 cfs {Max at site 6/23/ ,100 cfs}

19 HEC-HMS Interprets Rainfall Grid, Converts Rainfall to Runoff for each Subbasin

20 Model Calibration Simulation Evaluation Initial Assessment Focus: Upper portion of North Raccoon Watershed (Upstream of Sac City) ~900 sq. miles Includes Storm Lake Drains to Black Hawk Lake Storm Lake USGS near Sac City Black Hawk Lake

21 Model Calibration Simulation Evaluation Simulation: Peak = 8245 May 28, 2013 (11:55) Observed: Peak = 7510 May 28, 2013 (17:00) Volume is good, however, further refinement of timing coming from east and west headwater areas to be investigated

22 Model Calibration Simulation Evaluation During May 2013 at the time of this storm, the water surface of the lake was lower than the elevation of the outlet weir. Outflow from the lake occurs when the water surface elevation is greater than feet

23 Attenuation of Inflow by Storm Lake Inflow Outflow Storm Lake reduced and delayed the discharge to downstream in the watershed.

24 Sensor Deployment

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27 rainfall Hydrologic Sensor Network rainfall wind speed and direction Vaisala WTX531 soil moisture and temperature Vaisala WTX533 shallow ground water Campbell Scientific CS655

28 Hydrologic Sensor Deployment

29 Existing BMPs BMPs are being collected by 12-digit HUC and finished products can be downloaded at:

30 Agricultural Conservation Planning Framework: Staff Creek Watershed Conservation Practices: Drainage Water Management Grassed Waterways Buffer Strips Water and Sediment Control Basins (WASCOBs) Nutrient Removal Wetlands Saturated Buffers Further Information:

31 Iowa Soybean Association Headwaters Cedar Creek Watershed Study

32 Iowa Soybean Association Headwaters Cedar Creek Watershed Study

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34 A vision A for vision a more for a resilient more resilient Iowa Iowa The The Iowa Iowa Watershed Approach Iowa Flood Center The University of Iowa 100 C. Maxwell Stanley Hydraulics Laboratory Iowa City, IA

35 Watershed Planning Kyle Ament Iowa DNR

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37 Watershed Planning Locally Led (WMA and Lead County) Two levels of planning (HUC12) and (HUC8) RFA for Planning once WMA in formed

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41 Watershed Planning Should be Integrated with other planning efforts! Hydrologic Plan (IFC) Disaster Recovery Plan(HSEMD) Hazard Mitigation Plan (HSEMD) Resiliency Action Plan (IFC, CEA)

42 Source: ISA Cedar Creek Plan

43 Goals Develop a watershed-based management plan to enhance flood resilience and strengthen natural ecosystems (WQ, Species, habitat). Don t reinvent the wheel- integrate and build upon previous work. (Previous master plans) Questions?

44 Iowa Watershed Approach Jim Marwedel, State Hazard Mitigation Planner March 2017 A vision for a more resilient Iowa

45 Connecting the Plans A vision for a more resilient Iowa

46 Hazard Mitigation Plan What is it, and why? One reason why : The Mitigation Plan is the key to funding streams under FEMA s Hazard Mitigation Assistance (HMA) HMA provides $ to plan and implement actions (projects) that: Reduce the impact, and/or Reduce the expense of natural hazard events The Hazard Mitigation Plan identifies those actions that reduce risk of hazards (i.e. mitigate hazard risks). A vision for a more resilient Iowa

47 FEMA Hazard Mitigation Assistance (HMA) Programs: HMGP - Hazard Mitigation Grant Program To implement long-term hazard mitigation planning and projects after a Presidential disaster declaration PDM - Pre-Disaster Mitigation Provides funds for hazard mitigation planning and projects on an annual basis FMA - Flood Mitigation Assistance Provides funds for planning and projects to reduce/eliminate risk of flood damage to buildings that are insured under NFIP

48 Mitigation Projects Funded with PDM or HMGP In Iowa Acquisitions With demolition With relocation of building Safe rooms (weight rooms, classrooms, auditoriums, swimming pool locker rooms) Flood walls Well houses Generators for vital services (like water, wastewater, police dispatch and firestation doors) Warning sirens Installation of pumps (for flooding) Iowa and/or Elsewhere Retrofit overhead lines Sewer reconstruction Lift station reconstruction Sanitary sewer flood protection Structure Elevation Dry floodproofing Elevation of HVAC, appliances, etc. and/or other wet floodproofing Soil stabilization Extraordinary post-disaster code enforcement costs

49 Hazard Mitigation Plan and Watershed Plan Another reason to have Hazard Mitigation Plan: So we ll know what to do to avoid future damages and problems (Even if we can t get funding from FEMA) The watershed planning process can help us figure that out! So, idea is: Use the watershed planning process to develop mitigation plan for flooding Incorporate the watershed plan into the Hazard Mitigation Plan Use the WMA as a means to accomplish flood mitigation actions And, do this without jurisdictions having to do extra effort A vision for a more resilient Iowa