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HomeMy WebLinkAboutStorm Presentation City of MedinaStormwater SystemPhase 1 March 22, 2021 Research Field Investigation Mapping Phase 1 Scope Historically drainage of property was implemented to remove stormwater and shallow groundwater from property in order to: Farm Develop into cities Construct road network Drainage/Runoff History Land development created problems: Downstream flooding Erosion Filling of shipping channels Pollution of drinking water supplies Habitat damage Loss of recreation Runoff Problems Specific modern pollutants/problems: Oils and grease Heavy metals Nutrients Bacteria Fine sediment Temperature increase Flashy hydrologic response Specific Modern Runoff Issues Stormwater Runoff is: Dirty Ubiquitous Diffuse Highly variable Nobody wants it Stormwater Runoff Summary Standard of Practice for conveyance design Development of runoff models Clean Water Act of 1972 Nationwide Pollutant Discharge Elimination System (NPDES), Phase II State & Local Regulations for Development Regulation and Design 1985 Maps 1992 Comprehensive Stormwater Plan ~2010 GIS Basemap with Handheld GPS These resources were: incomplete Inaccurate Slow incremental development throughout the City – is system adequate? Research for City of Medina Field Investigation Find all system components Cleaning Needs Maintenance Needs Update the map: Gaps Collection points Outfalls Pipe size & material Updated map using GIS-based platform Asset Essentials tool: Tracking maintenance activities NPDES tracking Inventory Identify problems Mapping System Inventory Component Length, LF 12-inch or smaller 39,331 15- to 21-inch 3,841 24-inch 2,746 30-inch 44 36-inch 948 48-inch 84 60-inch 99 Unknown 5,749 Swales/Ditches 11,130 Catch Basins 1,012 Outfalls 24 Culverts 9 of various size General Findings Lots of older, smaller diameter pipes Variety of catch basins, frames, & grates Structures hidden by landscaping Additional video inspection needed Few treatment systems Few flow control facilities Next Steps Perform additional investigation Identify maintenance needs Identify capital needs Present needs to Council Mike intro Ryan: back story Roger: First, a little history. For most of time, humans have tried to get rid of water from their property Roger: But, with these development “improvements” come some problems Roger: As runoff flows across the land, it picks up lots of pollutants Roger To summarize…. Roger: Over the course of time, the management of runoff has evolved from a strictly engineering task to a mix of engineering, political, and regulatory task Roger: Now back to the work that has been done for Medina. Responding and resolving to runoff problems is an analytical task; and knowing your system is key to success Roger: Over the last 6 months, we had 3 junior engineers walk the City, with the latest GIS-based map on their phones and inspect the system Over the last 6 months, we had 3 junior engineers walk the City, with the latest GIS-based map on their phones and inspect the system Over the last 6 months, we had 3 junior engineers walk the City, with the latest GIS-based map on their phones and inspect the system Roger: Basically, what we found was an older drainage collection and conveyance system that may need upgrades to address new standards, new regulations, and changes in Medina Ryan/Mike?