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HomeMy WebLinkAbout191119 TF Staff Report_newNovember 19, 2019  Flood Risk Reduction Strategy Task Force  Ross Bintner, P.E., Engineering Services Manager  Flood Risk Reduction Strategy - Meeting 10  Introduction This report is meant to establish a framework, outline sectors of work, list possible actions in each sector for discussion, and to inform a prioritization exercise used in developing the flood risk reduction strategy. This outline would then be used to draft the staff report for the flood risk reduction strategy. Framework Climate change is the lead driver of increasing flood risk in Edina. We will use the framework provided by the IPCC for understanding the components of risk and actions to reduce risk, and a modified definition for flooding based on the FEMA definition. Flooding is the primary hazard relating to climate change that we are studying. Risk is defined by the hazard, and our exposure and vulnerability to it. Flood risk reduction actions will increase resilience by reducing exposure and vulnerability and may use resilience and adaptation strategies. Mitigation actions will reduce the rate of change of future hazards. Definitions Flood: A general and temporary condition of partial or complete inundation of normally dry land areas from: The overflow of ponds, lakes, wetlands or creeks; The unusual and rapid accumulation or runoff of surface waters from any source; The unusual flow of surface waters along planned or unplanned paths; Floods inundate flood areas or flood plains and flow along emergency overflow paths; Floodplain is classified as local or regional, and emergency overflow paths are classified as planned or unplanned, based on the CWRMP. Risk: Disaster risk signifies the possibility of adverse effects in the future. It derives from the interaction of social and environmental processes, from the combination of physical hazards and the vulnerabilities of exposed elements. Exposure: The nature and degree to which a system is exposed to significant climatic variations. Vulnerability: The degree to which a system is susceptible to, or unable to cope with, adverse effects of climate change, including climate variability and extremes. Vulnerability is a function of the character, magnitude, and rate of climate variation to which a system is exposed, its sensitivity, and its adaptive capacity. Flood risk reduction: Actions that reduce risk by: Reducing exposure to flooding or reducing the vulnerability of any system to effects of flooding. Resilience: The ability of a social or ecological system to absorb disturbances while retaining the same basic structure and ways of functioning, the capacity of self-organization, and the capacity to adapt to stress and change. Adaptation: The process of adjustment to actual or expected climate and its effects. In human systems, adaptation seeks to moderate or avoid harm, or exploit beneficial opportunities. Mitigation: A human intervention to reduce sources or enhance the sinks (or reductions) of greenhouse gases. *The term ‘mitigation’ is commonly used to describe a reduction in flood risk as well as to describe a reduction in atmospheric carbon. In this context, ‘mitigation’ refers to reducing carbon. Sectors Infrastructure (meeting 2) What is the outcome; Building infrastructures that reduces areas of vulnerability and are less exposed themselves to extreme events. The service provided by water resource and other infrastructure is defined in the 2018 City of Edina Comprehensive Plan and Comprehensive Water Resources Management Plan. Who does the work; Public Works, Engineering, private redevelopment, contractors, property owners. Who is involved; Planning, Building, future property owners. How is flooding risk considered; At decision points, in projects, design, failure analysis, during infrastructure planning. Gaps; Actual service level falls short of expected service, aging infrastructure, reactive maintenance, reactive emergency response, capital improvements do not have scale to ‘fix it’ or even keep up with climate change trend. Regulatory program (meeting 5) What is the outcome; New homes and buildings have reduced exposure to flood, and are less vulnerable to flood. Grading and private systems do not increase exposure of nearby properties, and reduce it if possible. Who does the work; Engineering, Building, private permit applicants Who is involved; Public Works, Planning, future property owners How is flooding risk considered; At application and permit, during construction, at final. Gaps; No impervious cap, long term maintenance of private drainage systems, limited areas of work, limited resources, very low existing homes/areas Engagement and outreach (meeting 6) What is the outcome; People understand the vulnerability and exposure to flooding, know what action to take to reduce each in the immediate, short and long term. People are motivated to take action to protect themselves. Who does the work; Engineering, Communications, partner agencies, community groups. Who is involved; The public, public and private organizations. Gaps; No coordinated plan and message, limited resources. Emergency services (meeting 6) What is the outcome; Parties respond, provide aid. Limited disturbance/damage. Rapid return to normalcy. Who does the work; Police, Fire, Engineering, Public Works, County/State/Federal Emergency Responders Who is involved; Executive leadership, emergency responders, property owners, visitors How is flooding risk considered; disaster planning, training and drills, post-hazard recovery Gaps; Current response is triggered only in major/severe events Possible Actions for Each Sector Infrastructure Better and broader awareness of system function Education and outreach program connections Standardize failure analysis and reporting Publish flood peak elevation visualization for entire system Publish flow path visualization for entire system Predictive snowmelt modeling (based on winter snowpack information – most informative for landlocked basins within the City) Retrofit or build new level sensors at key system points Reduce vulnerability of infrastructure systems Better maintain what we have Proactive assessment of condition Fixing minor issues before they cause a problem Control the sources of clogs and debris Maintain creek or swales to keep them clear of debris Sweep street more frequently Inspect private erosion and sediment control features Reduce exposure of infrastructure systems Raise or relocate sanitary lift stations out of floodplain Raise or relocate water supply systems out of floodplain Notify private utilities of flood prone facilities Reduce vulnerability of community assets Search easy to solve standalone retrofits such as single pipe constrains or inlet capacity constrained low points that associate with flooding Retrofit bigger pipes in specific flood areas Retrofit new storage into or under park spaces Retrofit new storage into or under roads Choose a future climate risk event commensurate with the lifecycle of the infrastructure. Plan emergency overflow paths Buyouts of vulnerable structures Incentive for redevelopment of vulnerable structures Surface water level measurements to optimize operations and monitor vulnerability Use new technology to increase utilization of time and space Retrofit predictive pumping on existing lift stations Consider flood storage with predictive pumping or valves to draw down water bodies in anticipation of a flood. Regulatory program Consider and reduce exposure at flood storage areas for a greater range of permitted activities Consider and reduce exposure in flow paths Consider and reduce neighboring home vulnerability on a greater range of permitted activities Consider and reduce neighboring home vulnerability on currently unpermitted activities Use regulatory program to reduce community vulnerability by controlling impervious Use regulatory program to reduce community vulnerability by requiring private flood storage Regulate development for bigger storm modeled inundation areas (500-year floodplain) Engagement, communication, education Proactively communicate flood threat with property owners Forecast with precip gages. model? Ice jams, saturated conditions, snow melt Groundwater level – is there a USGS gauge we can reference and generalize relative scale, low to high Promote WaterAlert (USGS) subscription for Gray’s Bay outlet Provide flooding and drainage resources Create and promote ‘What is my flood risk?’ map Searchable by address 10% and 1% chance layers Pulls in flood threat category (low, moderate, major) Pulls in groundwater level category (very low, low, normal, high, very high) “Where does the stormwater go?” application “What watershed am I in?” application (link to cleanwatermn map) Requests for service. Sandbags. Edina 311 How to sandbag video What can I do? City flood protection projects and programs Create community flood risk FAQ Gray’s Bay Dam CWRMP/FRRS history, TF process Local v. regional Drivers – climate change, service level expectations, land use Hydro 101 - Links to someone else that’s doing this well already. Technical assistance grant case studies How to sandbag Insurance Link to others tools (FEMA, USGS) Various other products referenced in other sections of this report Pre/during/post flood resilience – buildings Fact sheets for each and an overview comparing cost and appropriateness. Sump pumps, floodproofing, elevating utilities, insurance, smart storage in lower levels, sanitary backflow, sand bags, hydrabarrier, adopt-a-drain Contractor list Post-event call for photos/stories Pre/during/post flood resilience – landscaping Fact sheets and other resources Adopt-a-drain Contractor list Classes (Metro Blooms) Stormwater Technical Assistance Grant Case studies to FAQ Flooding and drainage expo (biannual?) Direct mail invitations to at-risk properties Looping video (<5 min) describing flood risk in Edina Looping video describing general tools and introducing available resources (<5 min) Print media and other resources One-on-one counseling (pre-register?) Expert panel – city staff, state climatologist, public health, housing, landscapers, floodproofers, engineers Private sector exhibitors Engage with stakeholders at time of capital investment Public Improvements Street Reconstruction Develop engagement plan as appropriate (Pamela Park water quality ponds rehab and 58th St Reconstruction example) Audiences/potential partners: residents, neighboring cities, watershed districts, state agencies, USGS/MGS, non-profit groups, volunteer groups, Master Water Stewards, lake associations, neighborhood/homeowner associations, realtors, appraisers, insurers, contractors, developers, businesses, commissions (Planning and Energy & Environment). Modes of dissemination: Face to face, Youtube videos, social media, print media (About Town, others), press release, online newsletter (City Extra), website, utility bill notices, literature handouts, infographics, direct mail, EdinaTV, presentations, events (Open Streets), workshops/training (Metro Blooms). 4. Emergency services Develop city-wide flood preparedness program Source flood threat information (stream gages, rainfall gages, precip gages, radar). Predict flood threat (model? Ice jams, saturated conditions, snow melt). Define affected areas/parties. Warning system and dissemination. Neighborhood/watershed specific. Local and regional messages. Emergency response plan. Tasks and assignment of responsibility. Equipment and supply requirements. Sources of assistance. Schedules for performance. Public information program. Continuing public awareness. Pre and post flood information dissemination. Maintenance and improvement program. Drills, training, routine updating, post-event debrief. Coordination with neighboring cities and other agencies (Watershed Districts, County, MN DNR). Info about what the City can and can’t do about active flooding; explanation of how the City prioritizes flood-related requests for service. Prioritization Criteria and Categorization In terms of a set of criteria such as the following; Effectiveness and confidence At reducing community vulnerability to flood At reducing community exposure to flood At reducing community share of climate change drivers Tradeoffs, possible regrets, other impacts, opposition Community impacts Land, other services Sustainability goals Environmental outcomes Cost, time and resources Minor; Savings or efficiency, takes minor amount of staff time, or can roll into existing duties with existing staff time and resources, <0 to 10hrs, <0 to $1K Modest; Modest additional costs, modest amount of staff time. 20 to 50hrs, $2-5K Moderate; Moderate additional costs, takes moderate amount of additional staff time, or can be contracted out in future budgets. 100-200hrs, $10-20K High; Additional costs, takes additional staff time, can be contracted out with additional resources. 500-1000hrs, $50-100K Major; Significant costs, takes significant amount of staff time, or can be included in future capital improvement plans. 2000+hrs, $200K+ Categorize based on composite scores Quick Win = do now or contract under flood risk reduction effort. Planning = develop a plan as part of flood risk reduction effort, or include in Comprehensive Water Resources Management Plan amendment, future budget, or Capital Improvement Plan (CIP). Development = may be worth doing with additional resources, a special circumstance, a partnership or technology improvements change cost structure. None = benefit is not worth the cost or effort.