Watershed Management Is Decreasing the Need for Humanitarian Assistance in the Sahel
This post was written by Julius Bright Ross (American Association for the Advancement of Science (AAAS) Science and Technology Policy Fellowship (STPF) fellow), Nicole Van Abel, Arif Rashid, Joseph Grange, Michael Manske, Elhadji Mahaman and Alexis Jones with USAID’s Bureau for Humanitarian Assistance (BHA).
Some miles outside the small village of Dan Gueza, under the bright sun and cloudless blue skies of southern Niger, a goat meanders away from a thicket of scrubby brown grass. Bleating softly, it moves on to another patch, quickly passing out of view among the dense thorns of Acacia trees. The vegetation might seem scant, but over the past nine years, vast swathes of Niger’s semiarid lands have undergone a dramatic transformation.
A decade ago, repeated droughts and soil overexploitation had left villages such as Dan Gueza and others like it with little to no crops or grassland for people or for grazing livestock to eat. Since 2014, BHA has funded the World Food Programme’s (WFP) Integrated Resilience Programme activities in Niger, conducting integrated watershed restoration with the dual goal of restoring silvopastoral ecosystems — those that rely on both trees and grass for forage — and improving the resilience of agricultural production.
Vulnerable households received food aid and cash in exchange for work to build half-moon bunds and zaï pits to capture water and topsoil runoff, to remove Sida cordifolia (an invasive, unpalatable species that crowds out native vegetation), and to encourage productive tree growth on agricultural lands. Because of these efforts, soil quality has improved and increasing vegetation now covers over 100,000 hectares of land, with 155,023 hectares targeted for completion by the end of 2023.
According to a local pastoralist, “before, if you left your goat, she’d be walking for 30 minutes and you’d still see her. Now if you leave your camel, you can’t see it in the bush.”
A collaboration between BHA and NASA assessed these vegetation changes by measuring the increase in overall greenness over the course of the program (published January 2023 in Nature Scientific Reports). NASA’s Landsat 7 satellite provided data on greenness across 18 sites with soil and water conservation structures through the normalized difference vegetation index (NDVI), which provides a measure of the quantity of actively photosynthesizing plant material covering a given patch of ground. On average across these sites, annual peak NDVI increased from 2010 to 2020 by nearly 50 percent. The study also controlled climatic drivers of increased vegetation by comparing nearby sites to find over 25 percent relative NDVI differences between experimental and control sites. In other words, while increased rainfall helped, BHA-supported interventions were key to the increase in vegetation.
In early 2023, a BHA team visited four of the 18 areas studied in the NASA analysis and found meaningful on-the-ground improvements. Participants reported significant restoration of degraded land, improvements in water harvesting, more porous and nutrient-rich soil, slowing of desertification and the return of many flora and fauna species not seen in years. Herders no longer have to travel as far to find food for their animals, and there is more of it to go around.
There was more food for people to consume as well; all 13 communities visited reported increased millet and sorghum yields, with annual production ranging from 1.5 to 5.5 times what people had produced previously. One farmer described this change more tangibly: before adopting soil and water conservation measures, he would spend three months farming and the food he produced wouldn’t last three months. Now, he has food year-round.
While most households report that their crop production does not last the whole year, their stock runs longer. Before, “we had to rely on tree leaves (hanza and jiga) to survive the lean season; now we have food. Goats and sheep eat the tree leaves now."
Silvopastoralists still face challenges. While BHA support has improved food, firewood and environmental services, few of these benefits translate into liquid assets. Hay and seed sales provide some income, but the geographic areas for communities to maintain are necessarily large, and as a result, only some had operational plans to maintain half-moons. Some structures have begun to fill with soil and reduce their water retention capacity, and BHA saw no expansion of the approach planned for other communal pastoral sites. Alternative models for generating income from these silvopastoral interventions may be required for their maintenance and expansion.
The integrated watershed work on agricultural lands is proving incredibly popular. Households widely reported they had replicated soil and water conservation structures on their own land — including many nonparticipants. And there is no question why — everywhere you look, livelihood options are improving. As productivity goes up, some households are even experimenting with new crops, such as sesame and groundnuts, diversifying their nutrition and income.
In 2021-2022, Niger suffered a severe drought. Cereal production dropped by 39 percent and in some regions, 61 percent of adults went hungry to give more to their children. Even so, the WFP estimated that 80 percent of villages in affected areas covered by the Integrated Resilience Programme — roughly half a million people — did not need humanitarian assistance during this difficult time. These data are key; as semiarid regions across the world face historic droughts, this work shows the strength of watershed management for mitigating this devastating natural hazard.
Ultimately, there is progress yet to be made, but as one man interviewed for BHA’s 2023 assessment put it: “before we participated in the program, a year like last year would have been harder.”