What is a Swale?
by Jesse Fox, Tel Aviv, Israel 
on 02. 4.08
In this video from The Permaculture Research Institute, Geoff Lawton explains the simple yet elegant concept that is the swale. Formally defined by Bill Mollison as "long, level excavations, which can vary greatly in width and treatment from small ridges in gardens, rock-piles across slope, or deliberately-excavated hollows in flatlands and low-slope landscapes," the actual function of the swale is so simple and effective that it's a wonder we don't see more of them dotting the landscape.
When partnered with trees, swales are an excellent tool for recharging groundwater, reducing soil runoff, capturing water for agriculture and creating rich, green landscapes in hilly areas. Appropriate to arid and humid areas, steep slopes and flatlands, urban and rural areas, swales hold water for several days, until it is gradually absorbed into the soil.
For a visual explanation about how to build a swale, check out this site. For more in-depth info, check out the writings of Bill Mollison and David Holmgren.
Via:: The Permaculture Research Institute
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"...it's a wonder we don't see more of them dotting the landscape"
Go to SE Asia. There they inject them with steroids and call them rice paddies. been using them for thousands of years, I hear.
I like to compensate for living the the Dutch flatlands by spending my summer holidays in the mountains (Pyrenees, Alps, Wales, Scotland). There I have seen many new bulldosered roads, that change into mudstreams when it rains. I was wondering if the swale concept could be used to somehow lessen the erosion caused by these news roads.
A swale looks like mosquito breeding ground to me.
Mosquito breeding ground ... every storm sewer with standing water is a potential mosquito breeding site, and are ubiquitous throughout urban/suburban areas ... and, have no natural predation or sunlight.
If you're concerned about mosquitos, what is already all around is a much greater threat. Out of sight, out of mind.
bloody 'eck, made one of those at my house without even realising that it was a swale! And it works EXACTLY like in the movie!
This looks like how hillsides in California become oversaturated and collapse in mudslides. Nice idea, but it needs to be done very carefully and only in the right areas.
I'm a civil engineer and using a vegetated swale with a low slope is a great way to treat stormwater runoff and encourage recharge. That being said, I would like to interject that a swale is more properly defined as a sloped channel that is used to convey stormwater runoff. Most people connotate a swale with a "ditch". It can be lined with vegetation (typicaly grasses or small plants) or gravel, or even in some cases pavement or concrete. Although some swales are designed with an outlet to maintain some level of (standing) water within the swale, they can be designed to drain to a "dry" level if mosquito breeding is of concern. To address some of the comments: 1. Yes, swales are typically used along roadsides to collect runoff from roadways and adjacent areas and are an integral part of an erosion and sediment control program. 2. In very few cases should a piped storm drainage system contain standing water. The objective of this type of system is to remove water from an area quickly.