Home › Forums › SUSTAINABLE CONSTRUCTION, ENERGY and WATER CONSERVATION › Water Conservation › French Drains/Drainage Pits
September 22, 2013 at 6:28 pm #257910Gabs247Member
We have a 50m long block which has a mild slope down from the road. We’re building a new house, and have planning consent to put in a drainage pit/French drain to absorb any run off from paths/driveways, and then any overflow from the tank can flow out to the storm water drain (as gutters/tank should be higher than street level).
I’m planning to put a small orchard of fruit trees at the back of the yard, effectively the bottom. I guess drainage will be important, especially because the soil has a high clay content. What I was thinking, was digging a deep, narrow channel in between a row of fruit trees, which will be the low point so any water flows into the drainage pit and will have capacity to allow water to slowly seep into the ground without water logging the fruit trees, but still providing them with a source of underground water.
My questions are:
– Is this crazy, and will it create more problems than it solves?
– Is there a good way to determine the depth that will allow the fruit tree roots to take a drink without drowning them or causing rot?
– Is there a way to calculate the size of storage that would work well?
Basic research has indicated that watering trees anywhere from 300-500mm below the surface at the drip line is optimal, and I was thinking having it say half a metre deep, a metre wide and maybe 10 m long…which would be about 5KL water capacity minus the gravel or substrate? I have an area of 6m x 12m, and so was thinking of putting in two lines of trees, so this drainage pit would be about 1m from each tree.
Any advice appreciated.
gabsSeptember 22, 2013 at 8:50 pm #533802SnagsMember
Swales are a great way of charging the ground with water
Turn you clay into top soil and problem solved
Gypsum, mulch, microbes,crusher dust,bio char and sand if you can get it and lots of time.September 22, 2013 at 9:10 pm #533803Gabs247Member
Thanks Snags, I will probably be improving the soil in some way.
Some people suggest gypsum, some people suggest sand…not sure which is better, or wehther a bit of both?
But I guess I’m wondering if the idea of drainage pit would work as a potential extra water storage or just cause problems?September 22, 2013 at 9:29 pm #533804SnagsMember
Use everything you can get cheaply/can afford.
Most of all heaps of organic matter
Grow lots of green manure crops.
Constantly fill your swales with mulch
Get the worms to do the digging and aerating.
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