View Full Version : Dam on steep slope 20-30, any advice?
Hi, i recently purchased a piece of land on the island of lombok in indonesia, am looking to build a small dam for water plants, ducks, fish. not sure of size yet, will start digging and see how i go.
90% of the block is very steep, so i have no choice but to build on slope. all work will be done by hand, so will take a few months, no rush really :)
i am aware of all the erosion possibilities with the onset of the wet, as i won't be able to stabilise the area till it is completed i was thinking of building a retaining wall out of bamboo down slope to become my dam wall?? then stabilising it with vetiver to take over as the bamboo breaks down. open to any advice and ideas.
01-09-2010, 10:14 PM
Selamat datang Jjef! Apa kabar?
Swales, or keyline dams are the words you want to be searching on. And maybe gabions. Of course terraces would be pretty prevalent through your region too. I only have a regular backyard so I don't have the expertise myself but there are others here that can help out.
02-09-2010, 04:44 PM
You are close enough to the Wet Season to wait a bit longer and observe how the block handles the water and which way it goes etc. You can also start small and use the force of water to loosen or wet the soil a bit and make for easier digging.
Local advice is probably best here. Also if you want to kick off swaling get a couple of kerbau and one of those long bajak they use for deep ripping. Should be cheap enough to hire.
Lastly, wouldnt it be better off to put a dam at the bottom of the slope? I appreciate you are probably thinking keyline here. If so it may be prudent to get some level pegs and topographically plot your land.
thanks for your advice. my block is very simple, 30x50m on the side of a hill, it is pretty obvious what will happen when the rain hits, no real outstanding topographical features and there are no flat bits so no bottom of the slope :)
plan is to have it close to the house so i can jump of the deck on hot days.
i will definitely be starting small. do you think building a retaining wall out if bamboo is a good idea?
thanks again jjef
02-09-2010, 08:45 PM
with steep slopes like that, your best hope for a stable dam is to use good, free draining rock fill or gravel. Obviously to hold water, you would need to have clay, but stability is provided by the rock fill with a good, stable foundation. The rock fill is used as a "butress".
@ adrians - well there is no shortage of rock around here, it's bloody heavy but a great idea, many thanks
04-09-2010, 09:49 PM
I visited the 'island of cowboys' as a kid. This is where Indonesia 'shot it's westerns'. A nice place. Jjef, you can build some amazing stuff by relying solely on local bamboo culture. So you can achieve whatever you want with local knowledge. Ask the village heads..
05-09-2010, 09:16 AM
You could plant bamboo around the bank and use it as a growing support wall. Geoff mentioned something similar in one of his video's. The bamboo will grow fairly quickly and you can move the soil down from the top of the bank to form a dam around the bamboo. Since the work has to be done by hand the bamboo can establish as you build it up over time...
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