Catching and directing water with a swale
I am sometimes unsure why the Sunshine Coast is called that, when we can get such massive rains. Last week we had around 350mm in 30 hours. This came following a heavy rain in the week before and continuing rain during that week, so the ground was absolutely saturated! The reason I am only posting this article now, is because our phone line was washed away and we were without phone or internet for about a week…
On Monday morning, after a night of heavy rain, we went and checked the swale and the dam. Tom made our big swale an overflow of our dam, to ensure excess water was directed away from our house, animal pens, driveway and access roads.
|Our dam is to the right, this is the overflow going over an access road|
We followed our swale and noticed the water was moving too quickly in the swale. It is supposed to move no quicker than walking pace, and it was definitely moving quicker!
|The swale mound starting to flood|
|Water pouring into the swale from the bank|
|Puddles forming on swale mound, held back by the lip|
The swale mound was starting to flood, water was pouring into the swale from the bank and puddles were forming on the swale mound.
Tom was very happy he had spent some time creating a lip on the mound, which was doing its job and keeping the water in.
The swale did a good job at redirecting the water, at the end of the swale it flowed down a grassy hill, causing minimal erosion and was directed to join the creek.
|Overflow rapid over grass|
|The swale overflow water running
down the hill over the paddock
|Our access road; the creek had swollen
so much, the road itself was a river…
To date (16 March 2012) we have had 1382.4mm of rain this year. It is the most we have had in a short period of time, and it has made Tom realise that the large swale (see article http://permaculture.org.au/2011/08/03/farm-tour-of-kin-kin-souls-permaculture-demonstration-site-plus-one-tip-you-must-know-before-for-setting-up-your-first-swale/ ) needs help, and that another swale needs to be dug on the other side of the dam and go the other way, to moderate the water flow. It will also have a spillway, with sandbags we can then regulate the flow either way. We live and learn, and sometimes we need events like this to realise what is needed on a property. Eventually we would like to incorporate more dams in our swale system. But everything is done bit by bit, and we will get there in the end!
©2012 Permaculture Research Institute Sunshine Coast – Permaculture swale systems