3.4 Local Environmental Knowledge
The DEM image generated considerable interest amongst participants. The first step was to orientate the image to local landmarks, to enable those present to identify their own land on the DEM and situate their understanding of the real world three-dimensional landscape within the context of the two dimensional aerial view. Once done, participants used the infographic tool to begin relating their understanding of water flow across their own land, and its associated connection to gullying downslope. This was the first time that local participants could see ‘from above’ how the complexity of landscape topography played a critical role in whether specific mitigation actions would have the planned effect:
VLG1: In order to fill gullies and look as what we see from the map, we have to plant grasses as it looks down there. This erosion occurs because when the rainwater flows from the upslope it lacks barriers which protect soil from being washed away. So now as the water flows downslope it erodes soil and leave cracks on land surface. All we have to do is plant grasses and trees.
Although initial discussions centred primarily on how hydrological processes had created rapid overland flow leading to severe erosion and gullying downslope; the focus rapidly shifted towards the physical drivers (lack of effective terracing in upland farms to slow overland flow; lack of trees and vegetation upslope) and associated socio-economic drivers (lack of conservation agriculture knowledge, skills or resources; lack of compliance) as this participant notes:
VLG8: Some of people living uphill there haven’t terraced their farms and when it rains water flows through their farms till down here.Facilitator: Why is it that some haven’t terraced their farms. Have they not been told or it’s just that they don’t want? VLG4: It’s because of ignorance because everyone has got their own knowledge and understanding. You can find someone lacks even the basic knowledge of doing something in order to prevent soil erosion.
Further discussion highlighted a particular issue on land outside of private ownership, where less effort was made on soil erosion mitigation, and where water was directed towards, to avoid eroding private land. This resulted in faster flow along cattle trackways and paths which were located on common areas. In order to deal with this specific issue, participants identified areas on the map which could be zoned as priority areas to plant trees and shrubs in order to mitigate and slow hydrological flow. The DEM played a critical role in enabling participants to identify the areas for actions likely to have most impact in slowing flow based on their overview of the topography; and supported a much more focussed debate regarding the specific actions (tree-planting; terracing; education) needed to suit the differing soil types in each area:
VLG6: First of all, the places you see are fields that people grow crops. Although people farm, there is a difference in soil between one zone and another. Where you see there is erosion is the newly cultivated farming area and the other side which is uneroded it’s uncultivated area. And areas you see as eroded are cultivated areas. Erosion takes place downstream there. But what causes erosion downstream is the difference in soil between down here and up there. Therefore, as water flows from upstream it doesn’t erode as it does down here.
Using the DEM, participants also reflected on the relative success of the demonstration plots set up with the community during the original Jali Ardhi project. These areas highlighted the close coupling between institutional factors, such as the commitment of village leadership to maintain these areas as livestock exclusion zones. As a result of that commitment, gullies in the excluded zones had begun to show significant vegetation growth, with the resulting reduction in hydrological flow across this lower-level topography, as this participant noted:
VLG2: Another lesson, you might for example set aside an area for 3 years without livestock getting in. […] For example, down there you can see we have set an area and prevent cattle from getting in and we have seen changes as gullies are now filling up. The best practice therefore is to set an area and leave it for a while without allowing cattle in so as to allow grasses grow and reduce speed of water flow.
The community-led outcome of this workshop was a commitment to deliver a tree and shrub planting programme, with specific species and planting locations selected by community members. In order to facilitate this next step, a community tree committee was set up, led by the Village Leader, with externally-provided practical training and support in planting techniques and ongoing maintenance. This programme was delivered during the short rainy season in December 2019 to allow the trees to use rain for survival.