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General Permit 2 Information

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Overview

Stormwater runoff from a construction site carries sediment and other pollutants that have a negative impact on water quality and aquatic life. According to a National Water Quality Inventory completed by the Environmental Protection Agency, stormwater runoff is a leading source of water pollution. The U.S. Environmental Protection Agency estimates that 20 to 150 tons of soil per acre are lost every year to stormwater runoff from construction sites.

General Permit No. 2

Stormwater erosion control

Controlling erosion can significantly reduce the amount of sedimentation and other pollutants transported by runoff from construction sites. To keep our valuable water resources clean the Iowa Department of Natural Resources (IDNR) issues a General Permit no. 2 for projects that disturb one or more acres. Site owners and their contractors must meet several requirements with the goal of preventing stormwater pollution during and after construction.  

 Apply for a General Permit 2 (link to Iowa DNR Website)

Construction projects that disturb one or more acres or less than one acre of soil if activity is part of a “larger common plan of development” greater than one acre are required to obtain a General Permit No. 2 through the Iowa Department of Natural Resources. General Permit no. 2 requires that a Stormwater Pollution Prevention Plan (SWPPP) be submitted to the Environmental Services Division for approval. 

Required Stormwater Pollution Prevention Plan (SWPPP) Documentation

  • Description of the project
  • Contact information for project owner, contractor, and SWPPP manager
  • Certification Sheet signed by the owner, contractor, and any subcontractors
  • Site map showing where erosion control is to be implemented
  • Summary of stabilization practices
  • Copy of inspection sheet to be used for erosion control inspections completed every 7 calendar days
  • Permit Authorization issued by the Iowa DNR for General Permit No. 2
  • Copy of General Permit No. 2

The permit holder is responsible for compliance with permit requirements. The City’s MS4 Permit requires City staff to conduct inspections on all sites having an NPDES General Permit No. 2. Below you will find several resources including example SWPPPs, General Permit 2, and inspection form for projects with an active General Permit 2.

Erosion and Sediment Control

Erosion control practices attempt to stabilize disturbed soils in order to prevent soil particles from being transported to nearby waterways. Effective controls prevent detachment of soil particles and minimize the deposition of sediment downslope or offsite.

General Permit No. 2 in Iowa requires the installation and maintenance of effective controls to minimize the discharge of pollutants into Waters of the United States and to minimize the amount of bare soil exposed during construction. The permit also requires controlling stormwater volume and velocity to minimize channel and streambank erosion.

Examples of Best Management Practices

The Iowa Statewide Urban Design and Specifications (SUDAS) specification manual Chapter 9 and design manual Chapter 7 provides guidance on some of the following practices. Common erosion control practices used in Iowa include:

Sediment and Velocity Control Practices

What is Sediment Control?

Sediment and velocity control practices attempt to slow and trap sediment-laden runoff onsite, which helps filter pollutants and minimize further erosion. Sediment controls are often considered the “last line of defense” before sediment-laden runoff is discharged into Waters of the United States. Therefore, investments in effective erosion control practices can reduce the need for sediment controls.

Examples of Best Management Practices

The Iowa Statewide Urban Design and Specifications (SUDAS) specification manual Chapter 9 and design manual Chapter 7 provides guidance on some of the following practices. Common best management practices in Iowa include: