Storm Lake, Iowa Green Infrastructure Plan for Water

In 2014, the City of Storm Lake, Iowa was chosen for a pilot project by the Iowa Economic Development Authority to develop a plan for city-wide green infrastructure technology for improved urban water management - including storm, sanitary, and potable water solutions. This Plan is meant to serve as a case study and guidance document for green infrastructure planning in other communities. The Plan demonstrates a process that can be replicated and scaled to any size city.

The Plan emphasizes green infrastructure practices that mimic natural processes to restore natural hydrology, improve water quality and increase biodiversity. The report provides an assessment of the overall water condition of Storm Lake, stormwater modeling, land use scenario templates, key green infrastructure practices and strategies, and an Implementation Plan. 

The first step in developing the water plan was to identify green infrastructure tools appropriate for accomplishing the performance goals and standards applicable to Storm Lake. The Plan’s “Green Infrastructure Toolbox” includes recommended high-performance green infrastructure strategies. 

The applicable green infrastructure tools identified include:

  • Green Roofs
  • Permeable Paving
  • Street Trees
  • Bioretention
  • Naturalized Swales
  • Naturalized Detention
  • Cisterns
  • Wastewater Discharge Reduction 
  • Onsite Wastewater Treatment

Each tool is described in terms of the benefits it provides, how it functions, and its estimated performance based on previous installations.

Land Use Templates were developed to demonstrate the application and integration of these tools in typical settings found in the area. The Templates illustrate potential arrangements of Toolbox strategies for the given land use. 

Four templates were used based on predominant land use throughout the city:

• Downtown Commercial

• Residential

• Campus

• Big Box Commercial / Industrial

 

The Plan also includes stormwater modeling of most areas of the City of Storm Lake identifying surface flood areas and recurring flood patterns. Appendix C provides further details on the modeling and pollutant load estimation approach.

For green infrastructure practices that capture pollutant loads near their source, unit area pollutant load maps identify those land use areas where green infrastructure practices should be targeted to have the greatest pollutant load reduction benefit.

In addition, the report has an Implementation Plan which identifies three phases of capital projects to achieve short range, medium, and long-term performance objectives around water. The “Implementation Scenarios” include public improvement (streets and parks) as well as private and institutional site enhancements and renovations. Each Scenario reflects a different set of assumptions regarding individual green infrastructure practices, level of green infrastructure implementation within a Template, and targeted implementation of green infrastructure Templates. The Implementation Plan presents a case for  short-term expenditures as a strategy to attract long-term support and community investment.

Storm Lake adopted a post-construction stormwater control ordinance (Appendix A) for new development and redevelopment in an effort to minimize runoff and non-point source pollution.

 

Publication Date: April 2015

Related Organizations:

  • Iowa Economic Development Authority
  • City of Storm Lake, Iowa

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Resource Types:

  • Case study
  • Planning guides

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