Water harvesting at PORET
Mini dams are constructed along the gullies to capture the rain as it flows down the slope. We have planted the edges with pawpaws and other food crops, which not only make use of the water but also strengthen the dam walls.
PORET operates in a semi-arid part of Zimbabwe. Being in climatic zone 5, harvesting water is critical if we are able to realise our goal of transforming desert into habitat. To demonstrate how it is done, PORET has embarked on constructing a comprehensive water harvesting system in its Upper Forest garden. The aim is to slow the flow of water over the landscape when it rains, through a systems of swales and dams, to sink the water into the soil.
Swales are the digging of a ditch along the contour, normally 0.5m deep and 1m wide. Not only does this slow the water, but it also reduces soil erosion and protects the land below the contour. The edge of the ditch can be planted up with trees and other vegetation which increases water capture and reduces evaporation.
We have constructed 34 dams at the Centre, with a water holding capacity of over 1 million litres. Most importantly, the success of this system has inspired others to do the same. The project has led to the implementation of water harvesting techniques across all three wards in which PORET works.
55 farmers have taken part in the project from 18 villages across all three wards. 10,436 metres of swale have been dug, amounting to a potential volume of over 3m litres of water if they are filled by the rain.
Unfortunately in the 2019/2020 season we experienced a drought and therefore it has not been possible to fully test the water systems that have been created. This is an ongoing project. We'll keep you updated.
Before & after:
The picture on the left shows the process of constructing the dam. On the right, the dam is filled after a rain.