Sustainable Agriculture Extension Manual

Gully reclamation

Once they start, gullies can rapidly erode valuable topsoil and expose the subsoil or bedrock, and making the land very infertile. It is important to halt the process of gully formation early, before they have had a chance to erode a large area. Reclaimed gullies can make valuable land for growing crops.

Location

This method has been used in Zvishivane District in Zimbabwe, a dry region that gets an average rainfall of 400-500 mm a year. Most of the soils are sandy. Due to a lack of ground cover, water runoff is a big problem and many gullies have formed.

Advantages

Stopping gullies recharges the water-table and may make water available in the dry season.
It reduces the amount of soil erosion downslope.
It turns a totally unproductive area into productive land.

Work on reclaiming a gully starting at the top. The storm drain higher up diverts the bulk of the water. Build more stone barriers downslope.

Disadvantages

Gully reclamation requires a lot of labour.
It is treating a symptom. The real problem is higher in the watershed where the water is coming from.
Sometimes it does not work if a very heavy storm comes at the beginning of the reclamation work.

Requirements

Rocks, vetiver grass (or another tough bunch- or creeping grass).
Wheelbarrows, picks, shovels, iron bar to dig out rocks.

Procedure

1. Construct a storm drain above the gully to lead the water away from it. Do this in such a way that the water is well-managed and does not lead to erosion itself.

2. Start work at the top end of the gully. Throw the soil from both sides into the gully, down to where you want to build the first stone barrier. This soil will introduce grass seeds into the gully as well as flattening out the gully sides.

4. Construct the first stone barrier across the gully floor. Make the barrier widest in the middle, so that it has a point of stones facing upstream to break the force of the water. The barrier should be at least 1 m wide and 30 cm high. It should cut into the gully walls on each side.

5. Below the barrier put flat stones on the gully floor to break the force of water flowing over the barrier.

Working from the beginning of the gully downwards to where the first stone barrier will be built the steep sides of the gully are flattened with the soil being thrown into the gully.

6. Plant vetiver grass (or another strong bunch- or creeping grass ) below the barrier, and on the banks that have been bevelled above the barrier.

7. Going downslope, build barriers roughy every 10 m across the gully.

8. During rains, soil will settle and gradually fill up the area behind the barriers. When it is full of soil, add more rocks on top of the barrier to trap more soil. Keep the wall 1 m thick.

9. Plant trees and shrubs along the side of the gully. These should not cause too much shade, as this would not allow the grass to grow.

Gully reclamation in Mudenda, Zambia

A large gully had developed in the village of Mudenda, Kalomo West, Zambia. In October 1997, a team from CARE-Zambia's Livingstone Food Security Project and the Department of Agriculture conducted a participatory appraisal to understand the causes and consequences of this gully. This revealed that the community recognized that the catchment was not well taken care of as a result of bush fires, overgrazing, deforestation and inappropriate cultivation. The men of the village were afraid the gully would expand further and threaten other fields; but the women, who collected water from the gully and grew vegetables on its sides, wanted to develop a water-harvesting scheme for it. The community agreed to rehabilitate the gully and to continue to harvest water from it.

Several visits to the village by project and department staff helped establish rapport and enabled the outsiders to understand the different perceptions of the men and women. These led to an agreement to conduct a second participatory rural appraisal, focusing on

the Mudenda gully. During the first day of this appraisal, the villagers mapped the community, its resources and social structures, listed the rainfall history of the area, and collected the yields of crops. This information helped the community and the staff to analyse the catchment-level issues surrounding the gully and how the community used it, and to understand the link between soil erosion in the catchment and low crop yields.

The second day of the appraisal consisted of a holistic planning exercise. The villagers were first asked to think about possible solutions to some of the issues identified the previous day. They then drew up plans to revegetate the upper portion of the gully, improve their land-husbandry practices (such as by using cover crops) around the gully (and especially upstream from it), build a fence around the gully, and build a drop-structure at the head of the gully to prevent it from eroding further upstream.

The villagers emphasized that their conservation efforts should have benefits in the short- as well as the long-term. It was important to analyse the views of different members of the community, as in this case, men and women saw the gully from very different perspectives. -For more information, contact Robby Mwiinga, CARE-Zambia.

In areas where it is difficult to find rocks, logs can be used. They should be pegged and tied in place. Another alternative is to use sacks filled with sand or soil. Make small holes in the sacks for grass to grow through.

Do's

Keep livestock away from gully until it has been reclaimed.
Use other measures to control water runoff above the gully, such as harvesting water off paths and roads.
Repair and extend the walls if necessary, for instance if a flood washes away sides of the gully on one side of the wall.
Learn how to reclaim a small gully first, before trying to do the same on a larger one.

Don'ts

Don't create another gully with the storm drain.
Don't make the gap between the barriers too wide.
Don't build the barriers too high too quickly. A gully has to be healed gradually.


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