Erosion Control & Slope Hazards

Erosion ControlControlling sediment from entering our waterways and contaminating our streams and rivers has historically been a difficult task. Storm water management has evolved over the years from primarily flood control to improving our water quality as well. With the development of our community due to increased population growth it becomes even more important to pay more attention to water quality.

As we increase the percentage of impervious surfaces such as roads, parking lots and rooftops, we increase the risk of additional pollutants including sediment entering our streams and rivers. Sediment in streams fills gravel beds which spawning fish need and clouds the water which impairs the feeding ability of fish and can clog gill passages.

Erosion Factors
The problem of erosive materials entering our waterways can be attributed to several factors. Although a certain amount of the problem is a result of natural causes, the construction of new development, especially hillside development, also plays a role. Today, you must be concerned with how much, and how clean, water flows from your site. Part of this process entails controlling erosion on the site and preventing sediment from leaving construction sites.

Governing Ordinances
Ordinances governing requirements for installation of erosion control measures for development of property located in the slope hazard area can be found in Article 13.100 (PDF) of the City of Grants Pass Development Code.

The Slope Hazard Area contains land that has slopes of greater than 15%.

Best Management Practices
Measures that prevent erosion, commonly referred to as BMPs or Best Management Practices, include temporary and permanent seeding, mulching, dust control, and using undisturbed buffer zones. Sediment control methods can prevent sediment already suspended in runoff water from leaving a site and include use of silt fences, gravel construction entrances, sediment traps and inlet protection.

  • Before Construction -View information on basic best management practices that should be installed before construction begins.
  • During Construction - View information on some basic best management practices that can be done during construction.

Steep Slope Hazard Deadline
The Development Code requires that any construction work disturbing the soil or affecting the natural drainage and runoff shall terminate not later than October 15. The Parks and Community Development Director may, on a case-by-case basis, extend starting and completion dates by no more than 30 days based on the weather conditions prevailing at the time of the extension. To apply for an extension, fill out the Request for Extension to Work in the Steep Slope Hazard Area form (PDF) and submit it to the Parks and Community Development office.

To avoid fines, all construction sites must have erosion control measures in place by October 15.