The URL can be used to link to this page

Home My WebLink About2020-09-01 City Council Work Session Meeting PacketAgenda City Council Work Session City of Edina, Minnesota VIRTUAL MEETING Call 833-360-0793, enter Conference ID 3192517 to listen to meeting Tuesday, September 1, 2020 5:30 PM I.Call To Order II.Roll Call III.Morningside Flood Infrastructure Project Update IV.Adjournment The City of Edina wants all residents to be comfortable being part of the public process. If you need assistance in the way of hearing ampli$cation, an interpreter, large-print documents or something else, please call 952-927-8861 72 hours in advance of the meeting. Date: September 1, 2020 Agenda Item #: III. To:Mayor and City Council Item Type: Reports / Recommendation From:Ross Bintner P.E., Engineering Services Manager Item Activity: Subject:Morningside Flood Infrastructure Project Update Discussion CITY OF EDINA 4801 West 50th Street Edina, MN 55424 www.edinamn.gov ACTION REQUESTED: No action is requested INTRODUCTION: Engineering staff will present a project update for the Morningside Flood Infrastructure Project. Initial concepts for infrastructure options and their benefits, costs, and tradeoffs will be shared. ATTACHMENTS: Description Staff Presentation Morningside Flood Infrastructure Project City Council Work Session September 1, 2020 Ross Bintner –Engineering Services Manager 1.Context 2.Infrastructure Goals 3.Key Issues & Opportunity Areas 4.Infrastructure Choices 5.Discussion & Next Steps EdinaMN.gov 2 Outline Staff & Consultants •Ross Bintner –Engineering Services Manager •Jessica Wilson –Water Resources Coordinator •Sarah Stratton –Senior Water Resources Scientist, Barr Engineering •Patty Day –Engagement Specialist, Zan Associates How we work with the community to comprehensively reduce flood risk: •INFRASTRUCTURE: We renew our infrastructure and operate it to reduce risk. We plan public streets and parks to hold and move flood waters to reduce the disruption of city services. •REGULATION: We understand competing demands of land use and their effect on drainage, groundwater and surface water issues. We help solve issues while looking at the bigger picture. •OUTREACH & ENGAGEMENT: We make flood information available to the public and give residents tools for flood resilience to help reduce their risk. •EMERGENCY SERVICES: We help people prepare for floods, remove people from harm during floods, and help people and the city recover after floods. EdinaMN.gov 3 Context - Flood Risk Reduction Strategy EdinaMN.gov 4 Context & Timeline •Spring 2020: Flood Risk Reduction Strategy Approval •2020: Preliminary Engineering and engagement •2020-2021: Comprehensive Water Resources Management Plan Major Amendment & Utility Rate Study •2021: Design •2022: Phase 1 construction Morningside (Area D&E) •2023: Phase 2 Construction Morningside (Areas C) EdinaMN.gov 5 Content & Timeline EdinaMN.gov 6 •Safely store and move flood water by repairing and upgrading aging infrastructure to share benefits and risks neighborhood-wide •Lower flood elevations to reduce private property flood exposure •Upgrade and protect existing infrastructure to decrease flood exposure and vulnerability •Prepare for increased risk cause by climate change Infrastructure Goals EdinaMN.gov 7 EdinaMN.gov 8 Infrastructure Goals –How we view risk𝑭𝑭𝑭𝑭𝑭𝑭𝑭𝑭𝑭𝑭𝑹𝑹𝑹𝑹𝑹𝑹𝑹𝑹=𝑪𝑪𝑭𝑭𝑹𝑹𝑪𝑪𝑪𝑪𝑪𝑪𝑪𝑪× 𝑪𝑪𝒆𝒆𝒆𝒆𝑭𝑭𝑹𝑹𝒆𝒆𝒆𝒆𝑪𝑪× 𝒗𝒗𝒆𝒆𝑭𝑭𝒗𝒗𝑪𝑪𝒆𝒆𝑪𝑪𝒗𝒗𝑹𝑹𝑭𝑭𝑹𝑹𝑪𝑪𝒗𝒗 Flood Infrastructure Focus Reduce private structure exposure; reduce public infrastructure exposure; reduce vulnerability EdinaMN.gov 9 Infrastructure Goals – Drivers of increasing risk Plan for and address leading drivers of increased risk: PLAN: Climate change has already and will expose more assets to flooding in the future. This driver is predicted to overwhelm the other drivers in terms of scale. ADDRESS: Private and public asset and infrastructure are both exposed and vulnerable. Public infrastructure can define flood exposure for different points in the landscape, and serve as a pathway for private risk Infrastructure Goals – Pathways to structural flood risk EdinaMN.gov 10 Groundwater Sanitary Backflow Surface Water What is new? •2011 LIDAR •2019 Flow monitoring & stormwater model calibration •2019 2D Hydrologic model conversion •Best “neighborhood scale” flood map in the state •Room for improvement of flood map on a “lot-by-lot scale” EdinaMN.gov 11 Key Issue & Opportunity Areas What have we learned? •A lot about extent and risk of surface overflow paths. •Deep appreciation for the scale and interconnectedness of the problem •There is no substitute for elevation, and when an area is low, the opportunity window for new storage is narrow. •The limitations of pipe, the value of planned land overflows. Key Issue & Opportunity Areas EdinaMN.gov 12 Issue areas -downstream to upstream Weber Park Monterey to Grimes low area Grimes and Crocker steep flow paths Branson Key Issue & Opportunity Areas EdinaMN.gov 13 Major Flow Paths West to east pipe West to east surface North/South steep slope pipe and surface Major Storage Areas Land / Temporary Water Key Issue & Opportunity Areas EdinaMN.gov 14 Weber •41st and pond pipe system •42nd pipe system •41st overflow east Key Issue & Opportunity Areas EdinaMN.gov 15AvailWeber Park Weber Woods Weber Pond Low area west •Private surface overflow path •41st Right of Way •42nd Street Key Issue & Opportunity Areas EdinaMN.gov 16 Lynn/ Kipling temporary inundation area Susan Lindgren School Grimes/Crocker steep flow paths •over flow potential •Steep flow path Key Issue & Opportunity Areas EdinaMN.gov 17 Branson •Over flow Key Issue & Opportunity Areas EdinaMN.gov 18 •2020 Morningside Flood Videos from the latest hydrologic model are posted on the EdinaTV YouTube page •The playlist is available at: https://tinyurl.com/2020MFV Key Issue Areas EdinaMN.gov 19 •Scalability and cost •Levels of effort •0 –Status Quo ($2M) •1 –“Upgrade” (+$2M, $3k/lot) •2 –“Go big” (+$4M, $6k/lot) •3 –“Go bigger” (+$8M, $12k/lot) •Rate study connections •More discussion next time Infrastructure Choices EdinaMN.gov 20 •Storage •Flow path •Vulnerability Reductions •Cost •Benefit •Opportunities •Tradeoffs Infrastructure Choices EdinaMN.gov 21 •Water •Land •Surface •Pipe •Public •Private •Opportunities at Weber Pond and Lynn/Kipling Inundation Area •Low relative costs, high for floodwalls •Good flood benefit •Tradeoffs include loss of use of land, park or nearby trees. Loss of view for wall. •Could improve habitat and be part of new park feature. Infrastructure Choices -Storage EdinaMN.gov 22 •Floodwall Examples Infrastructure Choices / Storage EdinaMN.gov 23 EdinaMN.gov 24 Infrastructure Choices -Storage •Opportunities at Weber Park, Weber Woods, Susan Lindgren School, Avail Academy •Medium relative cost for grading, high cost for flood walls •Good flood benefit •Tradeoffs include more frequent flooding of land, limited use of land EdinaMN.gov 25 Infrastructure Choices / Storage EdinaMN.gov 26 •Example of extensive grading and pond expansion in storage option model run EdinaMN.gov 27 EdinaMN.gov 28 Infrastructure Choices -Storage •Opportunities at parks, parking lots. •High relative cost •Medium relative benefit •Less trade offs to land use, but future structures of improvements may be limited. EdinaMN.gov 29 EdinaMN.gov 30 EdinaMN.gov 31 EdinaMN.gov 32 Stormwater Infrastructure Choices -Storage & Flow Paths •Opportunities in flat street right of way •Very high relative cost for underground storage, low for surface, medium relative cost for flow path. •Low relative benefit for storage, medium benefit for flow path. •Tradeoffs include, need to mitigate risk transferred downstream and right of way conflicts EdinaMN.gov 33 EdinaMN.gov 34 Infrastructure Choices -Flow Paths •Opportunities on steep flow paths, and areas with bypass flow •Low to medium relative cost for flow paths. •High flood benefit to correct bypass, or plan for flow path. •Tradeoffs include, lowering streets, driveway impacts, utility impacts. EdinaMN.gov 35 Public Vulnerability Reductions •Sanitary lining •Manhole rehab •Floodproof or relocate lift station •Armor high flow paths / streets Private •Sewer service lining, backflow prevention, overhead sanitary service and many more… •http://www.edinamn.gov/Flooding Infrastructure Choices •Opportunities on existing sanitary sewer system, and Monterey lift station, •Variable relative cost •Medium relative benefit •Tradeoffs include construction impacts Major flow paths West to east pipe West to east surface North/South steep slope pipe and surface Major Storage Areas Land / Temporary Water Infrastructure Choices EdinaMN.gov 36 Combined Option •Pipes + Storage + Predictive Pumping + Overflows •$8M+ •Extensive tradeoffs •Good 20%, Okay 1% Infrastructure Choices EdinaMN.gov 37 Combined Option •Pipes + Storage + Predictive Pumping + Overflows •$8M+ •Extensive tradeoffs •Good 20%, Okay 1% Infrastructure Choices EdinaMN.gov 38 EdinaMN.gov 39 Discussion & Next Steps Share Information -Summer 2020 Information about flood risk, Edina's Flood Risk Reduction Strategy, and actions people can take to reduce their own flood risk will be shared. Present Initial Concepts -Fall 2020 Initial concepts will be presented for feedback. Present Refined Concepts -Winter 2020 Refined concepts based on feedback will be presented. Make a Decision -Spring 2021 Staff will make a recommendation and City Council will make a decision. Close the Loop -Spring 2021 The decision will be communicated to the public and archived on the Better Together Edina project page. EdinaMN.gov 40 Discussion & Next Steps Discussion Questions •General agreement with infrastructure goals? •General agreement with storage/flow path strategy? •Anything to take off the table? •Anything that must be achieved? •Which land or water areas seem to hold the most promise? •Guidance on balance between costs, benefits, tradeoffs, opportunities? •Rate study / CIP connections