Our vision of realizing reforestation for the entire valley of Vilcabamba has taken a step forward with the contract to design and supervise implementation of a 17 hectare property, El Mirador, in barrio San Jose de Vilcabamba. In the video we made for our crowd-funding project, Water and a Forest for Every Village, we mention the need for more and larger models. This property has the potential of filling the need for a mid-size model. The project proposal can be seen here
We are pushing the envelope on Permaculture standards for digging contour canals on steep slopes. When you collect water in any form, the effect of the water weight must be considered. Causing the land to de-stabilize is a concern.However, after 5 years of working these slopes with these methods, I've found that steeper drops within narrower canals can move the water safely off the mountain while accomplishing the aim of slowing the water down so it can penetrate the soil. Yes, there is risk, but doing nothing is more risky.
It is important to include an outlet when water is collected. We have used many "sills" in the project, which is a level cut in the down-hill side of the canal/swale wall. A sill creates a long spillway for the water to exit in a sheet. It can vary from one meter to several meters in length, depending on the scope of the project. In this project, because erosional breaks in the land are frequent, it makes it difficult to direct the water completely away from any erosion zone, before running into another. Thus, we used sills to spread the water out in zones that are less prone to erosion, and less steep.
Narrow swales, with a slope within the swale of .3-.6 % to help rainwater in a strong storm move off the mountain safely without furthering erosion. The vetiver grass forms a barrier subteraneally and above ground. Roots grow 4-5m deep and form a thick web.