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23:41, 19 November 2014 [[Image:rwsn_rain.png|right|80px|link=https://dgroups.org/rwsn/rainwater/]]
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| valign="top" rowspan="7" | <font size="5" color="#adadad"> <center><br><br>Using <br><br>local <br><br>materials <br><br>for pond <br><br>lining </center></font>
| style="border: 3px solid #efefef;" valign="top" | '''I was wondering if any of you have experience with lining surface runoff harvesting ponds, using local available materials as clay, bentonite or gley or cement/clay mixtures or that sort of stuff? Plastic liners are all good of course, but perhaps some local materials will also do the job if you allow some small seepage?'''
For instance, imagine I have a hole in the ground of 50 to 70 meter cubic somewhere at a small farm in Uganda where a farmer would like to grow tomatoes during the dry season using the runoff from her compound. Would properly puddled clay do the job or will it just crack up when empty and be useless the next year?
- M
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|style="border: 3px solid #efefef;"| Hi M,<br>
Here are some ideas we use in Western Australia. <br>
You could adapt them for your situation. These are other publications which go into more detail if you are interested.
- N <br>
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* [https://www.dropbox.com/s/mzunli8rv1bhzpt/Fixing%20Leaky%20Dams.pdf Fixing Leaky Dams.pdf] 0.1MB
* [https://www.dropbox.com/s/er0bs8tb5ftusfj/Designing%20for%20reliabl%23BC331.pdf Designing for reliabl#BC331.pdf] 54.0kB
* [https://www.dropbox.com/s/2cxwl7t6a3l5d3s/Using%20Windbreaks.pdf Using Windbreaks.pdf] 0.1MB
* [https://www.dropbox.com/s/6mkqleaxclyh6uh/Building%20Farm%20Dams.pdf Building Farm Dams.pdf] 0.1MB
* [https://www.dropbox.com/s/drercq60ad7yy5k/Building%20Roaded%20Catchments.pdf Building Roaded Catchments.pdf] 0.1MB
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|style="border: 3px solid #efefef;" |[http://searnet.net/ SearNet] conducted some on-farm trials of pond sealing materials and had very interesting results. We tried out engaging pottery experts to line the sides of the ponds using clay. the result is that depending on moisture/dry conditions, the layer expanded/contracted, and eventually they failed. My take is that runoff ponds seal themselves gradually. During Y1, the sealing is optimal but progressively become effective with time.
- A
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|style="border: 3px solid #efefef;" |Hi M,
This FAO document, Controlling Water Losses in Ponds, has some good ideas for sealing ponds.
Manual puddling may be combined with the overflow of a runoff infiltration pit (i.e. attempt to separate the fine clay particles from the heavier sand/silt) could work and doesn't involve transporting a lot of clay.
Moving pigs into a ditch that fills with water after rains and having them puddle & compact and somewhat "glei" it is also a traditional way to reduce soil infiltration, but it takes a while to work.
However you are right, longish dry-out periods will likely affect the pond seal.
- K
|style="border: 3px solid #efefef;" |[ftp://ftp.fao.org/fi/cdrom/fao_training/FAO_Training/General/x6709e/x6709e03.htm CONTROLLING WATER LOSSES IN PONDS]
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|style="border: 3px solid #efefef;" |Thanks B, <br>
I suppose this is a returning problem when using clay, you mean the ponds stop sealing themselves after year 1 already? I suppose also, if this is in really arid lands the long dry spell will make it more difficult...
- M
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|style="border: 3px solid #efefef;" |Does anyone have an example of ponds that have already worked for say 5 years in a development context? <br>
Thanks again!
- M
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|style="border: 3px solid #efefef;" |Hi M,<br>
Apart from focussing on the pond I would also suggest storing water where the crops grow by putting the right biology into the soil: soil bacteria secrete a sticky substance that glues soil particles together and gives the soil structure, greatly enhancing its water-and-oxygen-holding capacity. The fungi grow filaments of great lengths, functioning like extended roots and bringing nutrients to the plants from deep down and far away. The way to get these microorganisms is by creating a good compost pile (takes about one month) and from that making 'compost tea' (easy!) and then just spray it on soil and crops.
Concerning sealing the pond, yes pigs could work well, and cattle, because of their weight, even better...
- A
Sri Lanka
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