Rainscaping Iowa’s Landscapes

Wayne Petersen, Urban Conservationist,Iowa Dept of Agriculture and Land Stewardship

wayne.petersen@iowaagriculture.gov319-430-7480

Grey Infrastructure vs. Green Infrastructure

Grey Green

We need to utilize green infrastructure and LID in all new development

…and on all redevelopment

National Research Council - 200942% of urban lands will be redeveloped by 2030.

A second chance….

Rainfall Data 1948 - 2004

What we’ve been doing…

Regional wet detention ponds are becoming popular

Need green infrastructure throughout the watershed of wet detention ponds

D.A. = 48. 3 acresResidential = 34 acAg = 14. 3 acP. Surface= 2.4 ac

Or the water feature that should be an amenity becomes a nuisance and a liability

Practices / Projects throughout Iowa

» Green Roofs» Rainwater Harvesting» Soil Quality Restoration» Porous Pavement » Bioretention» Stream Corridor Stabilization

IDALS’s Urban Conservation Program

Amy Bouska,

Jennifer Welch

Wayne Petersen

Two UC positions are currently open.

Rich Maaske, from Council Bluffs, recently retired.

Steve Anderson, from Spirit Lake recently accepted a new position.

We hope to fill one position.

One will not be filled.

Need support for UC funding

Green Roofs

Sedum flats system being installed - Des Moines

Water Tower Place – Cedar Rapids

Genesis Hospital - Davenport

View from patient’s room

An alternative system that allows deeper soil media

Permeable Pavement(60% -70% of imperviousness)

Permeable pavers streets in Charles City

Permeable pavers in West Union’s business district infiltrates fire hydrant water

At the lot level – a permeable driveway in Des Moines

Bladensburg, Maryland Parking Lot

Installation

Reduced maintenance?

Rainwater Harvesting

1,500 gallon tank at Forever Green Landscaping - Coralville

6,000 gal tank capturing roof water for greenhouse use at Kirkwood Community College in Cedar Rapids

A rain barrel capturing roof runoff and overflowing into a rain garden. Permeable pavers round out this system in West Union that manages roof runoff.

Rain gardens

Rain garden at Forever Green Nursery and Landscapeing in Coralville.

Rain garden at a church in downtown Des Moines

Enhanced rain gardens

Before – a major problem for these Davenport neighbors

After - an enhanced rain garden solved the problem

Bioretention cells

Okoboji’s green street project

Davenport’s green street project

A curb cut lets street water flow onto a vegetative filter strip and then into this biocell

Summerbrook Park - Ankeny

Bioswales –enhanced rain gardens with grade.

Bioswales infiltrate the WQv and convey runoff from larger events

Before – gully erosion and wetness problems

After - a subdrain, enhanced soil, and check dams have been installed

After native vegetation is established in this Davenport bioswale

Soil Quality Restoration

» De-compaction» Apply compost to increase OM

content» Strive for Five (5% OM content

minimum)

Soil Quality Restoration

Decompacting

Incorporating compost to increase organic matter content

Aerate prior to compost application to create macro-pores.

Existing yards

Applyingcompostafteraeration to increase OM content

The neighbor’s untreated yard

Yard with fall applied

soil quality restoration

Early the following spring

Stream corridor stabilization

60% -70% of sediment loading is from stream corridor erosion

Properties threatened by stream erosion in Des Moines

Before – Field Sike Creek in Bettendorf

After sloping back vertical banks

Create a flood plain if room is available and budget allows

After native vegetation is established

Deep rooted native vegetationprotects the toe of the slope during frequent ,small bounces in flows

Flood plain of Catfish Creek in DubuqueCounty after 14 inches of rain fell overnightin late July 2011. Note the high water makr

Note how this outside bend of Catfish Creek held up during the high stress of this flash flood. Banks had been slopedback and vegetated with deep rooted native plants.

Room to improve

The downspout outlet and overflow riser should be 9 inches above the floor of the biocell.

The fix – raise the overflow pipe

Overflow pipe is elevated but perforated. Riser pipesMust be non-perforated to Impound at least 6-9 inches

The fix: non-perforated pipe forces water to pond to design depth.