Seattle Public Utilities
The Ballard Natural Drainage System project now complete will help prevent an average of 1 million gallons of untreated sewage and stormwater per year from entering the Ship Canal and Salmon Bay.

Ballard Natural Drainage system is complete: Here's what's next

The Ballard Natural Drainage System project, in the works for the past three years is complete according to Seattle Public Utilities. The work done will help prevent an average of 1 million gallons of untreated sewage and stormwater per year from entering the Ship Canal and Salmon Bay.

In a press release from Seattle Public Utilities they outlined how the infrastructure will be maintained and what the public can do to help.

"SPU is responsible for maintaining the roadside rain gardens. This includes the thin grass strips in-between the cells and walkways/sidewalks. It can take from one to three years for the plants to fully establish, so please be patient while they’re small and growing. During the early plant establishment phase, you can expect to see crews on site about once per month to maintain the plants, water, mulch, weed and mitigate sediment build up. After the establishment phase, SPU crews will be on site approximately quarterly to maintain the cells and ensure they are functioning properly.

The inlets to the cells will remain temporarily plugged with asphalt to allow the newly laid compost to settle with rain water and the plants to take root before they are immersed in stormwater. If we allow large streams of stormwater into the cell too early, it can remove or erode the compost and plants and create other maintenance issues. The plugs will be removed by our contractor this spring.

SPU crews will:

· Check for proper function

· Remove sediment

· Clear curb openings

· Remove trash and debris

· Remove weeds

· Water plants

· Prune, replace or remove trees if necessary

· Adjust soil grades as necessary

You can help by:

· Clearing curb openings

Please do not:

· Prune or trim vegetation

· Add or replace plants

· Use chemicals, herbicides, fertilizers or insecticides

· Add or remove soil, compost, sediment or fill

· Store items in the rain garden

· Remove dead or dying plants

· Plant edibles in the rain garden

· Play or work in the roadside rain gardens

After a heavy rain or storm, it is not uncommon to see standing water in the roadside rain gardens. The cells will typically drain within 24 hours after the rain stops falling. However, if you notice a system is not draining after 72 hours, or if it has been damaged in any way, please call SPU’s 24/7 hotline to report it at 206-386-1800. SPU will check the system to see if it needs any maintenance adjustments.

If you don’t have a roadside rain garden in front of your property, you may have an improved planting strip.

· New grass will be maintained by SPU for one year

· New groundcover and trees will be maintained by SPU for three years

Maintenance of the planting strips is the responsibility of the adjacent property owner after these allotted time periods. Street trees within the landscape strips are the property of Seattle Department of Transportation’s Urban Forestry program. Please be careful not to damage the trees when mowing or maintaining the planting strip.

On the project website’s Documents Tab, you can see how the natural drainage systems will change over time. For general information about maintaining SPU and King County’s green stormwater infrastructure, please see the online care guide.

To help us improve how we provide information about construction projects in the future, please fill out a quick survey at https://www.surveymonkey.com/r/BallardNDS by Friday, Jan. 27, 2017.

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