Holding up in the Rain: Success on Jordan Creek

In June 2016, a rain garden was constructed at the Central Council of Tlingit and Haida’s property at the Edward K. Thomas building located in the Airport Shopping Center. The rain garden has proven successful in handling its first Juneau rainy season.

The purpose of the rain garden is to capture and infiltrate the pollutant-laden stormwater that flows across the parking lot before it enters Jordan Creek. Stormwater is a concern for Jordan Creek because it is listed as an Impaired Water Body by the State of Alaska for non-attainment of sediment, dissolved oxygen, and residue (debris) standards, and urban stormwater run-off is identified as the major source of pollution.

The rain garden was designed to handle 1.51 inches of rain over a 24-hour period. However, the rock swale that provides a stabilized flow path and inlet into the rain garden has been effective in infiltrating most rainfall events before the water even makes its way into the rain garden (Photo 1 and 2).

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Photo 1. Rock swale during a rain event on 11/29/2016. Rainfall totaled 1.42 inches that day.

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Photo 2. The rain garden during a rain event on 11/29/2016. Rainfall totaled 1.42 inches that day.

 

 

 

 

 

 

 

 

Larger storms do make their way into the rain garden. A large storm in September 2016 topped the rain garden and stormwater had to discharge through the overflow outlet rather than infiltrate into the ground as intended (Photos 3 and 4). However, this storm was over an inch greater than the design storm.

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Photo 3. The rock swale during a rain event on 9/9/2016. Rainfall totaled 2.69 inches that day.

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Photo 4. The rain garden during a rain event on 9/9/2016. Rainfall totaled 2.69 inches that day.

The rain garden was funded by the Alaska Clean Water Actions (ACWA) Grant Program administered by the Alaska Department of Environmental Conservation and a National Fish and Wildlife Foundation (NFWF) Wells Fargo Environmental Solutions for Communities Grant.

If you would like more information about the rain garden project, please see our project website at http://www.juneauwatersheds.org/programs/stormwater/raingarden.html or contact JWP via email at juneauwatersheds@gmail.com.

SPECIAL THANKS TO OUR PARTNERS, WITHOUT WHO THIS PROJECT WOULD NOT BE POSSIBLE:

Central Council of Tlingit and Haida, for their overall project support

SOURCE, LLC, for donating staff and equipment time in construction

The Alaska Department of Environmental Conservation and National Fish and Wildlife Foundation for project funding support

U.S. Fish and Wildlife Service, for continued project advice and guidance

Trout Unlimited and Wells Fargo, for recruiting volunteers for installation of the fence and planting

All volunteers who participated

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A Rain Garden for Jordan Creek

Saturday, June 11, 2016, the Juneau Watershed Partnership (JWP), the Southeast Alaska Watershed Coalition (SAWC) and a handful of volunteers planted a rain garden built on the Central Council of Tlingit and Haida’s property at the Edward K. Thomas building located in the Airport Shopping Center. Volunteers planted a variety of native plants including willow (Salix species), lady ferns (Athyrium felix-femina), Alaska wild iris (Iris setosa), Tuft hair grass (Deschampsia cespitosa), Bunchberry (Cornus canadensis), and Red twig dogwood (Cornus sericea). The purpose of the rain garden is to capture and infiltrate the pollutant-laden stormwater that flows across the parking lot before it enters Jordan Creek (see Photo 1 below). Stormwater is a concern for Jordan Creek because it is listed as an Impaired Water Body by the State of Alaska for non-attainment of sediment, dissolved oxygen, and residue (debris) standards, and urban stormwater run-off is identified as the major source of pollution.

Runoff from Site

Photo 1. Stormwater run-off from the Edward K Thomas Building parking lot, prior to construction of the rain garden.

This project was the culmination of several years of work. The need for stormwater treatment at this location was originally identified in a stormwater inventory and assessment for the Lower Jordan Creek watershed conducted in 2012-2013 by the United States Fish and Wildlife Service (USFWS) and the JWP. The recommendations for this site were to:

  • Construct an infiltration basin on a portion of the gravel parking area to promote stormwater infiltration and trap sediment and other pollutants before they reach the stream.
  • Pave the remaining portion of the gravel parking area to eliminate sediment sources.
  • Use fencing to establish a 25 foot wide riparian setback from the outfall upstream to Glacier Highway to protect riparian area.

In 2014, the USFWS and JWP approached the Central Council of Tlingit and Haida (CCTHITA) with the idea of constructing a rain garden and installing a snow barrier fence to address two of the three recommendations; CCTHITA supported the idea.

The JWP subsequently listed the Edward K Thomas Building Stormwater Treatment project in the compilation of restoration, enhancement and mitigation measures for Juneau’s watersheds developed under a Coastal Impact Assistance Program (CIAP) grant. The JWP identified the Edward K Thomas Building Stormwater Treatment project as a high priority for the Jordan Creek watershed due to the benefits, land-owner buy-in, feasibility in construction, and ability to obtain funding, and developed a conceptual design for the project under the CIAP grant in order to facilitate its implementation.

The JWP then partnered with SAWC and CCTHITA to pursue funding for the construction of the stormwater treatment and the snow barrier fence. In 2015, funding was secured from the Alaska Clean Water Actions (ACWA) Grant Program administered by the Alaska Department of Environmental Conservation and a National Fish and Wildlife Foundation (NFWF) Wells Fargo Environmental Solutions for Communities Grant.

The construction of the snow barrier fence  was completed in the fall of 2015 (Photo 2) and construction of the rain garden was completed this month (Photo 3).

However, there are still a few finishing touches that remain. The JWP will install an interpretive sign near the rain garden to make the public aware of the project and explain its water quality benefits, and barriers will be placed to protect the rain garden from truck traffic. If you would like more information about the rain garden project, please see our project website at http://www.juneauwatersheds.org/programs/stormwater/raingarden.html or contact JWP via email at juneauwatersheds@gmail.com.

SPECIAL THANKS TO OUR PARTNERS, WITHOUT WHO THIS PROJECT WOULD NOT BE POSSIBLE:

Central Council of Tlingit and Haida, for their overall project support

SOURCE, LLC, for donating staff and equipment time in construction

The Alaska Department of Environmental Conservation and National Fish and Wildlife Foundation for project funding support

U.S. Fish and Wildlife Service, for continued project advice and guidance

Trout Unlimited and Wells Fargo, for recruiting volunteers for installation of the fence and planting

All volunteers who participated