Stormwater Management

Biscuit Creek retention pond

Managing Stormwater in Our Community
About Stormwater
Stormwater can pose a risk to our water resources. Pollutants in stormwater can impact lakes, streams, and rivers. Our community has adopted programs to control stormwater pollution.

Who Manages Stormwater Runoff?
The traditional approach to stormwater management focused on flood control. Today, Coralville manages both water quality and quantity by using practices that infiltrate more rainfall and reduce the volume of stormwater runoff. Residents, businesses, and builders and developers also have a role to play.

Notice of Proposed Update
To the City's Erosion & Sediment Control Ordinance
Proposed updates include:
  • Update of permit issuance guidelines
  • Update of stormwater pollution prevention requirements
  • Update of City inspection schedule
  • Addition of guidance for situations that involve damage to public property

View the Proposed Ordinance
View additions and deletions to the former ordinance (PDF)

Share your comments about the proposed ordinance by September 14, 2023, with Amy Foster, Stormwater Coordinator, at

Slow the Flow

Grants Available
Residents can apply for a grant to help install stormwater management practices on their property like rain gardens, soil quality restoration, and more.

Stormwater Management Best Practices Grants

Stormwater in Coralville
The City of Coralville proper consists of 12 square miles of mostly urban land uses. There are approximately 17 miles of streams, 1.5 miles of river, 7 regional stormwater ponds, and 900 infiltration-based stormwater practices (rain gardens, porous paving, infiltration trenches, green roofs, stormwater planter boxes, and soil quality restoration practices).

Where Does the Water Go?
All of the streams and ponds drain into the Iowa River. The Clear Creek Watershed and its tributaries (Biscuit, Muddy, Oakdale, and Un-named) collect 70% of the stormwater runoff in Coralville. The remaining 30% is conveyed to the Muddy Creek Watershed (and its tributary Altana Creek).  

Stream NameLinear Ft.Miles
Iowa River8,3661.6
Clear Creek35,3436.7
Biscuit Creek5,3501
Muddy Creek12,8492.4
Oakdale Creek7,4321.4
Un-named (west land use)11,4402.2
Altana Creek16,4723.1

Stormwater Best Management Practices Map 2017

What Is Stormwater Runoff?

Stormwater runoff is rainfall or snowmelt that runs off impervious surfaces like roads, buildings, and compacted soils. Stormwater runoff is collected and conveyed through storm sewers directly into streams, rivers, and lakes without being treated.

The Problem

Pollutants accumulate on impervious surfaces between rainfall events. Frequent, small rains wash pollutants into streams, rivers, and lakes. These pollutants negatively impact water quality.

As communities grow, impervious areas increase. Greater impervious surfaces cause the volume and rate of stormwater runoff to increase. This can result in flooding, stream channel degradation, and increased water pollution in our surface waters.

Learn More

  1. Residents
  2. Builders & Developers
Grants for Residents
Get help from the City when installing stormwater management practices on your property.
Link to page

Awareness, Responsibility, & Construction Sites
Prevent stormwater pollution, learn how pollutants are managed at construction sites, and report a stormwater concern.
Link to page

City Stormwater Regulations
See Coralville's requirements for the City's stormwater management program.
Link to page

Helpful Resources
Find guides to help you learn about and manage stormwater.
Link to page

Post-Construction Stormwater Ordinance & Redevelopment Policy
Learn about the ordinance that addresses how stormwater is managed on new development and re-development in our community.
Link to page