As part of RDG's comprehensive assessment of Ankeny's stormwater management system, eighteen miles of stream corridors were examined by land, water and air. An extensive GIS analysis of the watershed conditions across the City and within its projected 2040 growth boundary was completed.
RDG worked with the Iowa Flood Center to complete hydraulic modeling to evaluate existing and future conditions within key watersheds and around the community. The overarching goal was to recommend system improvements and evaluate policies to maintain a sustainable system of stormwater infrastructure for this community, which is expected to grow to nearly 90,000 residents over the next quarter-century. This Master Plan was developed after a year-long effort was completed in 2018, assessing conditions throughout the City of Ankeny and its potential future growth area. Extensive Geographic Information System (GIS) analysis was conducted to map and understand key properties and characteristics across these areas. This was paired with assessments of key stream corridors across the city. Collectively, these assessments were conducted to identify areas of streambank erosion, understand flood risk, analyze storm networks in select areas and understand how such items could be influenced by future land use changes. In the recent past, the City has spent millions of dollars on repairs related to stormwater issues, including addressing erosion and protecting infrastructure. There has also been flood damage to private properties. The Master Plan is intended to identify design methods, projects, policies and maintenance arrangements to address such issues proactively, to reduce the long-term potential of expensive repairs.
This Stormwater Master Plan defines the need for stormwater management as the City of Ankeny continues to grow. This plan was completed to:
• Identify current problem areas and infrastructure or properties that are at risk
• Review past stormwater management efforts and apply lessons learned toward future applications
• Recommend adjustments to policies to reduce long-term costs by addressing the causes of observed issues
• Determine methods to reduce the potential of flood damage in future growth areas
• Delineate clear standards that can be used by City staff when working with design professionals
• Detail resources required for projects, maintenance and acquisitions