County Low Impact Development (LID) Outreach County Low Impact Development (LID) Outreach BRIAN LEADERS, RLA REGISTERED LANDSCAPE ARCHITECT

Discussion Topics _______________________________________________  What is a watershed?  Why we need a Stormwater Management Ordinance  Problems caused by not having a Plan  Urban Conservation Problems  EPA “Today”  BMP’s (Best Management Practices)  Iowa DNR

What is a Watershed?

A watershed is a geographic area from which water drains toward a common watercourse (such as a lake, stream or ocean) in a natural basin.

When thinking of a watershed do not just think of water, include land, landuse, topography, geology etc. All of these components affect watersheds.

Why do we need a Stormwater Management Ordinance?

This is what we are seeing now!

Yes this is a paved street!

What problems are caused by not having a Stormwater Management Plan?

Watershed Hydrology BEFORE Development evapotranspiration: 40-50% interflow: 20-30% surface runoff: <1%

Watershed Hydrology AFTER Development evapotranspiration: ~25% interflow: 0-30% surface runoff: ~30%

Urban Conservation Problems ___________________________________

__________________________________ __________________________________ 10 to 20 times higher erosion than agriculture 10 to 20 times higher erosion than agriculture

Urban Conservation Problems ___________________________________ Storm water runoff is carrying high concentration of pollutants directly into creeks, stream and river. Storm water runoff is carrying high concentration of pollutants directly into creeks, stream and river.

Urban Conservation Problems ___________________________________ Developing in the fragile loess soils Developing in the fragile loess soils

Urban Conservation Problems ___________________________________ Rural vs. urban conflicts Rural vs. urban conflicts

EPA and Effluent Discharge Limits

Effluent Limitation Guidelines (ELG’s) _______________________________________________ On December 1, 2009, the U.S. Environmental Protection Agency (EPA) released effluent limits on stormwater discharges from many construction and development sites (the Construction Rule). (74 Fed. Reg. 62,996) 1 On December 1, 2009, the U.S. Environmental Protection Agency (EPA) released effluent limits on stormwater discharges from many construction and development sites (the Construction Rule). (74 Fed. Reg. 62,996) 1

The Construction Rule became effective February 1, 2010, and imposes the following general requirements: _________________________________________________________________________________ 1) Non-numeric limitations apply to construction activity that disturbs one or more acres; 2) Beginning August 2, 2011, a numeric turbidity limit and related monitoring requirements will apply to construction activity that disturbs 20 or more acres at one time;

Numeric Turbidity _______________________________________________ EPA’s Numeric Turbidity Limit is 280.

3) No later than February 2, 2014, the numeric turbidity limit will apply to projects that disturbs 10 or more acres.

EPA’s Main Goals Main Goals______________________________________________________  Preserve and improve water quality on a national scale.  Reduce sediment discharged from construction sites by four billion pounds each year.

Effective Controls and Required BMP’s ________________________________________________________ Controls are considered Effective When: “…bare soil is uniformly and evenly covered with vegetation or other suitable materials, storm water is controlled so that rills or gullies are not visible and channels or stream banks are not eroded.

Selecting temporary BMP’S (Best Management Practices) for you!

Down Gradient Perimeter Control _______________________________________________ _

Ditch Checks _______________________________________________

Channel Protection _______________________________________________

Temporary Ponding _______________________________________________

Construction Phasing _______________________________________________

Access Protection _______________________________________________

Inlet Protection _______________________________________________

Temporary Cover & Protection _______________________________________________

Spoil and Stockpile Areas _______________________________________________

Selecting permanent BMP’S (Best Management Practices) for you!

Rain Garden _______________________________________________

Infiltration Berm _______________________________________________

Soil Testing Infiltration and Embankment _______________________________________________

Sand Filters Sand Filters _______________________________________________

Dry Detention _______________________________________________

Wet Detention _______________________________________________

Constructed Wetlands _______________________________________________

Grassed Swales _______________________________________________

Dry and Wet Swales _______________________________________________

Grassed Vegetated Filter Strips _______________________________________________

Pervious Pavement _______________________________________________

Open Channel Flow _______________________________________________

Iowa Senate File Bills _______________________________________________ Working on an act related to flood plain management.

In a nut shell… _______________________________________________  Prohibit the reconstruction of structures and infrastructure substantially damaged by floods in a floodway.  Limit reconstruction or new construction in a flood plain.  Require new construction of facilities critical for health and safety of the public and the environment to be located in areas that are not flood plains whenever practicable.

In a nut shell… _______________________________________________  Conduct a subsurface tiling study to determine the impact that tile drainage has on infiltration, surface runoff, and flooding.  Evaluate the feasibility of seasonal retention of water in tile drained fields as a drainage management strategy.  Integrate multipurpose wetlands into watersheds.

In a nut shell… _______________________________________________  DNR will seek funding to plan, implement, and monitor a watershed demonstration pilot project for urban and rural areas involving a twelve=digit hydrologic unit code subwatershed as defined by the United States geological survey.

In a nut shell… ______________________________________________ IOWA DNR WILL CONDUCT A STUDY PROJECT THAT SHALL INCLUDE FEATURES THAT SEEK TO DO THE FOLLOWING: 1. Maximize soil water holding capacity from rain. 1. Maximize soil water holding capacity from rain. 2. Minimize severe scour erosion and sand deposition 2. Minimize severe scour erosion and sand deposition during floods. during floods. 3. Manage water runoff in uplands under saturated soil 3. Manage water runoff in uplands under saturated soil moisture conditions. moisture conditions. 4. Reduce and mitigate structural and nonstructural flood 4. Reduce and mitigate structural and nonstructural flood damage. damage.

In a nut shell… _______________________________________________  DNR will change climate criteria due to weather changes. Adopt minimum storm water standards to be implemented July 1,2011 to limit: Adopt minimum storm water standards to be implemented July 1,2011 to limit: 1. Limit water runoff 2. Reduce potential future flood damage 3. Assess effects of stream channelization 4. Improve watershed management for both water quantity and quality.

In a nut shell… _______________________________________________  Modify NPDES permits to require the mitigation of soil compaction and replacement of topsoil as part of the completion of construction for permitted actions involving one or more acres of disturbed land.

Stormwater Management is here.

Questions? _______________________________________________ Special thanks to the following sources:  Mike Isensee CPESC, Urban Conservationist Farmington, Minnesota Farmington, Minnesota  Blayne W. Renner, NPDES Stormwater Coordinator  Iowa Department of Ag. And Land Stewardship  Natural Resource Conservation Services  - _______________________________________________________________ BRIAN LEADERS, RLA REGISTERED LANDSCAPE ARCHITECT ROSEWOOD ROAD UNDERWOOD, IOWA