Rainwater and Land Development

Ohio’s Standards for Stormwater Management, Land Development and Urban Stream Protection

Stream systems, including their corridors, and wetland resources are vital environmental features and are extremely sensitive to urbanization. The intent of this book is to allow development to occur while minimizing the impact to water resources, especially streams.

This manual defines Ohio’s standards and specifications for storm water practices implemented during land development. The target audience is that group of professionals involved in the design and implementation of development projects, but it is also used by others interested in implementing sound practices that minimize erosion, sediment and storm water impacts.

The manual integrates water resource protection into development site planning in order to maintain or improve stream integrity. Early chapters discuss practices and strategies for protecting streams and wetlands, treating storm water pollutants, and establishing permanent runoff controls. The latter chapters include chapters regarding construction-phase practices, including standards and specifications for sediment control, temporary runoff control, soil stabilization and control of pollutants other than sediment. Appendices offer additional important information for design such as storm water design examples, soils, planning around streams, and use of and impacts to soils.

Manual Updates

The last entirely new edition of the Rainwater and Land Development manual was issued in November of 2006, but new materials have been added with changes and corrections made since that time. These are always included in new printings and in files posted to this site, but your manual may be older and need updating. Since 2012, updates have been indicated in the manual’s table of contents (Introductory Information) and is the best way to see what has been updated and when it occurred. You are encouraged to provide your name and contact information to us in order to receive news of updates and proposed changes for the manual (john.mathews@epa.ohio.gov).

Stream Channel and Flood Plain Erosion

To control pollution of public waters by soil sediment from accelerated stream channel erosion and to control flood plain erosion caused by accelerated storm water runoff from development areas, the increased peak rates and volumes of runoff shall be controlled such that:

  1. The peak rate of runoff from the critical storm and all more frequent storms occurring on the development area does not exceed the peak rate of runoff from a one year frequency storm (of 24 hours duration) occurring on the same area under pre-development conditions.
  2. Storms of less frequent occurrence than the critical storm, up to the one hundred year storm, have peak runoff rates no greater than the peak runoff rates from equivalent size storms under pre-development conditions.

The critical storm for a specific development area is determined as follows:

  1. Determine by appropriate hydrologic methods the total volume of runoff from a one-year frequency, 24-hour storm occurring on the development area before and after development.
  2. From the volumes determined in (a), determine the percentage increase in volume of runoff due to development, and using this percentage, select the 24-hour critical storm from this table.

If the percentage of increase in volume of runoff is:

Equal to or Greater Than
and Less Than
the Critical Storm for Peak Rate Control will be

1 year
10 20 2 year
20 50 5 year
50 100 10 year
100 250 25 year
250 500 50 year
600 100 year


Download the Ohio Storm Water Control Guidebook


Central Office Storm Water Technical Assistance Staff

Mathews, John


(614) 265-6685

Reinhart, Justin

Water Resources Engineer

(614) 705-1149


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