Storm/Wastewater Strategies

[Kevin Fraser]

Looking for case studies and precedents of storm and wastewater treatment/mitigation strategies, such as drainage swales, permeable paving types, retention ponds, etc… Specifically systems that are feasible on relatively steep slopes (streets) and can handle alot of rain (ie. Costa Rican cloudforest levels)…

Any help would be much appreciated!

cheers

[Roland Beinert]

Portland’s green streets are the examples that come to mind. Here’s a link to their website: http://www.portlandonline.com/BES/index.cfm?c=44407
The website has details and pdfs you can download. I’m not sure how steep the slopes are on the Portland’s green street’s, since I haven’t been to Portland all that often. As you may already know, you’ll have to slow the flow of the stormwater on a steep slope , so it has time to infiltrate. There are many strategies for doing this, but in general water will slow down when you have a wider channel and obstacles like rock dams. I think it’s better to have multiple areas and strategies that infiltrate a relatively small amount at a time than one big area that has to hold and infiltrate it all.

[Kendall Flower]

Hi Kevin,

Take a look at terraced rice cultivation and the system of steps and spillways Terracing would be a way to slow the flow of water, and increases the amount of water that can be infiltrated (or deal with larger quantities). Also look at agricultural practices in the Andes… and then reduce the scale of the whole idea just a little bit.

Also – how’s it going? :o)

[Tosh K]

I remember seeing terraced bioswales somewhere online (had to design one for a development in VA). Don’t know where it was – the thing with steep slopes and heavy rains is that you will need a fairly large volume storage area that is relatively flat to allow for long term infiltration.
As for US examples, the bioswale options from the Mid-Atlantic/Southeast areas probably match your rainfalls better than Northwest. Maryland has some “go-to” examples and details (search under LID/Stormwater).

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