“There isn’t a cookie-cutter, one-size-fits-all approach,” says Lauren Grubbs, lead engineer. “We wanted to give the city a realistic plan that catered to its staff’s availability and timeline. Instead of creating more responsibilities for the city, we delved into all the activities that they were already implementing that could also count toward their MS4 goals.”
Based on the assessment, our team updated the city’s stormwater management program plan with reasonable BMPs — and within an aggressive timeline — and compiled documentation on the city’s existing activities and practices that support its MS4 goals. Next, training was held to educate staff on identifying and documenting relevant tasks and metrics that demonstrate the city’s ongoing effort to resolve compliance issues.
To meet the conditions of the good housekeeping minimum control measure, we conducted a detailed stormwater inspection and analysis of the city’s public works maintenance facility. From that, we developed a facility stormwater runoff management plan that outlined specific responsibilities, in a monthly inspection checklist format, for each of the four city departments using the facility. The plan, specific to the site, also included training for facility staff on the proper storage of equipment and materials to better protect the city’s streams.
Documentation for these plans is accessible via a digital file and hard-copy binder, allowing staff members to easily make updates as well as compile information for the city’s annual report.
Expanding on the regulatory base of the stormwater management program plan, our team also was tasked with refining the city’s stormwater master plan. Its original plan had served its purpose, with many of the defined projects constructed over a 20-year period.
Instead of developing the traditional capital project list, which would require significant funding, our team took the master plan in a different direction. In conjunction with TREKK Design Group, we developed a suite of tools that provide real-time analysis of stormwater issues using current city data. Among these tools are hydrologic and hydraulic calculations and parameters for delineated watersheds, major overland flow paths, flow path obstructions and drainage service request layers. The tool set, developed in a geodatabase framework, is compatible on a multitude of platforms, including Esri’s ArcMap, Google Earth and ArcOnline dashboard. Though Grandview already had an ArcGIS Online account, its use of the software was fairly limited.
Layering these tools together paints a picture of how water moves through the city, allowing city engineers to not only know there’s a potential drainage problem but also begin to understand the source of that problem. These tools identify locations of current drainage issues, visually showing where the issue is located with respect to major overland flow paths and obstructions to that flow path. Engineers also can see how much area (acres) is draining to that point and how much stormwater (cubic feet per second) is anticipated during various storm events.
Additionally, these tools can determine if existing pipes meet the minimum level of service per current regional design standards, as well as estimate the pipe capacity needed for future development. With the right tools in an easy-to-navigate dashboard, the city can better manage stormwater on a day-to-day basis and more accurately address drainage complaints with the public.
RESULTS
In December 2018, our team provided a fourth-quarter update to MDNR on behalf of Grandview, with proof that the city had taken corrective action, as promised. MDNR agreed, and the city is now fully back in compliance. Open communication with MDNR and staff members helped generate a solid game plan, within a nine-month time frame, to address compliance issues.
That same month, we also handed over the new stormwater tools to the city, which staff members started using the same day. This new master “plan” sets the stage for the future of stormwater management in Grandview, providing technical and communication tools for everyday use. This work will save the city time in responding to drainage complaints, reviewing development plans and preparing the MS4 report.
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