Bioswale as rainwater harvesting media, how effective is it?

Question

Bioswale as rainwater harvesting media, how effective is it?

Answer 1

Depends on how well it is designed and what it keeps the rainwater from.

Answer 2

SWALES

On slopes we plow contours very slightly declining ,you have to do it with a level just enough to drain ,

At the end you have a wide part and a little bit deeper ,this is the swale

the rain water runs down the slopes along the contour in to the swale

and slowly drains into the ground .

this feeds the underground water supplies after it has saturated the ground above ,

after a series of these ,on the bottom you could have a well or a pump and pump the collected underground water up again.

Water over the ground takes minutes to move along and usually into ditches ,into creeks or rivers

But by redirecting it into the ground it takes months

in Dry parts of the country you can ensure growth by many months if you do this because of the wet ground .

Sand underneath works almost the same as a pond ,sand absorbs and hold water ,so failing a dam you direct water in to sandy dips and can also have a pump on the low end .

dry ponds are holes that fill up with water during the rain,but they are sandy or at least leaky ,do not hold the water for long ,usually only a few days ,or if there is clay underneath in patches, maybe a week .

But as mentioned above this water is not lost ,it is only out of sight ,and is stored in the ground .

just check after a heavy rain ,only the top few inches of the ground is wet ,because the water moves to fast ,

So to not waste the rain water ,we direct it into the ground .

I made one garden ,in Africa in front of a huge mountain wall ,this in itself collected tons of water during the rains ,by digging a ditch in front of the mountain ,

I controlled the water leading into various ditches going down hill(never straight ,so as not to have to much erosion,into many holes ,with over flows continuing in ditches to the next hole ,(the holes varying from a few square meters,

and then into level deep ditches .closed at intervals ,with an over flow ,using a pipe into the next one ,and so on.

About 5 large ditches in all ,the last one almost never got water ,

all of it had gone into the ground by then ,and in any case at the end was a water retaining dam.

the rain falls in this part of Africa are enormous and can wash away roads in hours ,or flood fields .

this never happened in my big water system spanning a few acres which was the vegetable gardens

The fact that not a drop of all this water left the garden ,is called zero run off ,which is the rule of the principle of water harvesting in PERMACULTURE

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