One of the most important steps to take in our site is to ensure enough water for the whole year, even in the driest period. In our case we decided to make an earth dam, according to the techniques given in the Permaculture Design Course (PDC). In another article later will we get pictures of the whole process, but now we could say that it has made only with stone and earth of the place itself, entirely by hand and no machinery, just pick and shovel, two people, working approximately three full days.

It was made in several steps, and was looking forward to do in case there was any change in the original design. The end result was very satisfactory, but it remains to see how it evolves over time and especially to see if it holds the winter time that sometimes there is too many water.

The dam has a height of 1.5 m and a width of 6m, inside contains approximately 7m3 of water,  it takes to fill about 3 hours and can be emptied through a valve in about 45 minutes for maintenance. It has two water outlets with prefilter and filter, leading to the house and future garden, the other will be used to produce electricity with a self-builded small turbine. There is a height difference of 10 m, so falls by gravity and gives enough pressure to the house. The potential to generate electricity is low but enough for our needs (lighting and small appliances such as laptops, mobiles, etc, do not want more).

The place where we put the dam is very clayey and moist soil, rich in herbs of all kinds. The water flowed on the surface, a minimum flow like a faucet, not accumulated, spent all along the ground without embalming. Here we see a picture of the land before the changes:

The ground where we have the dam

At the time of the access road was opened a ditch leading the water through a pipe under the road outside, to avoid eroding the road. One year ago I made a pond test closing the ditch, I used a wooden board, a stake to hold it and a plastic liner. Could save 1m3 of water. Here is how it looked:

Pond test a year ago

After the work the result is as follows:

The earth dam completed

We see the dam, built with stone at the bottom to build well, and compacted earth on top. To his right the overflow made ??of stone to prevent erosion,  excess water drains underneath the road. A ditch on the right leads the excess water drain directly to ground without passing through the dam to prevent overfill in the rainy season. At the bottom we see the set of valves and tubes, is pending to protect them with a chest. Right there is the drain, although not shown in the photo. And finally a photo of the inside of the dam:

View from the dam

We see two areas of different depth, one on the right has 1.5 m, at the bottom are the output tubes and water filters. On the left an area of ??about 30 cm deep, in the future can be emptied for more volume of water stored if necessary. The water runs slowly but continuously, our experience with the pond test is not full of algae.

In future articles I will explain more details.