The impact of nature-positive interventions for improved watershed management in the Western Ghats of India

CGIAR’s Nature-Positive Solutions Initiative (NATURE+), in collaboration with partners Mahatma Phule Krishi Vidyapeeth Rahuri (MPKV) and BAIF, conducted a study on nature-positive watershed strategies for carbon sequestration in two micro watersheds in Akole taluka, Ahmednagar district, Maharashtra, India. The study’s purpose was to provide a comprehensive understanding of how watersheds function and how nature-positive solutions can optimize their role in carbon sequestration. The research reinforces the importance of sustainable watershed management in building resilient and climate-adaptive landscapes.

Land degradation and soil erosion are urgent challenges, with almost 40% of the world’s land degraded, according to the UNCCD’s Global Land Outlook published in 2022. The mismanaged land resources, including soil, water, and biodiversity, impact a quarter of the world’s population by causing food insecurity, decreased access to safe water, disease transmission, and economic hardships. Extreme weather events, such as floods and droughts, further aggravate land degradation, causing loss of soil structure, nutrient loss, soil salinity, and compaction, affecting soil health and productivity.

The primary drivers of land degradation are water and wind erosion, which affect 94.87 million hectares of land in India (ICAR, 2010). Degradation of soil affects soil fertility and increases sedimentation and pollution in water bodies, reducing the water-holding capacity of the land, leading to flooding and loss of biodiversity. When natural resources are degraded, it disproportionately impacts vulnerable local populations who heavily rely on ecosystem services for survival and livelihoods.

Through effective management of land resources, the negative impacts of soil and land degradation can be reduced. This is feasible if we start working at the watershed level, which has great potential to measure and anticipate the negative impacts of land degradation on upstream and downstream communities.

Chichundi village in the Western Ghats

Situated in the Western Ghats, Chichundi village in the Akole cluster is rich in scenic beauty and biodiversity that attracts tourists in the monsoon season. Located in the rugged hilly terrain, watershed-1 (136 ha) and watershed-2 (63 ha) (see figure below) within the village receive an annual rainfall of approximately 1,700 mm. High runoff within the watersheds frequently erodes the topsoil.

The two watersheds have more than 40% of the area affected by moderate to extremely severe soil loss, causing the loss of associated carbon and nutrients. The reduced levels of soil organic carbon directly affect soil fertility, limiting the soil’s capacity to support productive vegetation. The soil is predominantly sandy loam to sandy clay with high drainage capacity, largely minimizing the water retention within the watersheds, causing water scarcity in the non-monsoon period.

This seasonal water scarcity forces the local community and farmers to rely extensively on the groundwater. Over-reliance on groundwater further intensifies water scarcity in the region by widening the gap between groundwater recharge and withdrawal.

Nature-positive interventions in the watersheds: soil health and carbon sequestration

Nature-positive soil and water conservation interventions in the two watersheds of Chichundi village were implemented by BAIF with the expertise of MPKV Rahuri, IWMI, and supported by Alliance of  Bioversity International and CIAT as part of NATURE+. Interventions such as drainage line treatment and land area treatment were implemented to enhance carbon sequestration potential, improve soil health, conserve water, and prevent land degradation in the watersheds. The drainage line treatment involves check dams, gabion structures, loose boulder structures, and percolation tanks, whereas the area treatment involves bunding, trenching, and terracing in the watersheds.

Drainage line treatments focus on controlling water flow and sediment transport, while land area treatments aim to reduce erosion and improve soil moisture retention. Together, these measures are expected to create a more resilient watershed capable of withstanding the impacts of hydroclimatic extremes.

Observed impacts of nature positive interventions

Within the study period (2023-2024), the overall soil loss was reduced by approximately 18% in both watersheds, contributing to better soil health and enhanced soil stability. Consequently, a significant decrease in the rate of carbon loss was observed. Within one year of nature-positive interventions, the carbon loss rate decreased by more than 21% in each watershed. This reduction further indicates the enhanced carbon sequestration capacity across the landscape with the effective interventions.

Rainfall and runoff directly impact water movement, soil loss and associated carbon loss, particularly in the peak monsoon months of July and August. Despite the increase in rainfall between 2023 and 2024, the post-intervention runoff depth did not rise at the same rate, indicating effective soil and water conservation due to bunding, trenching, and terracing. The average runoff coefficient — a measure of the fraction of rainfall that becomes surface runoff — decreased from 0.42 to 0.32 in watershed 1, and 0.28 in watershed 2. This reduction highlights an improvement in water retention within the watersheds, with more rainfall infiltrating the soil rather than contributing to the surface runoff after nature-positive interventions.

Conclusion and way forward

Implementing nature-positive soil and water conservation measures in the watersheds of Chichundi village significantly improved soil health and hydrological dynamics. A substantial reduction in soil erosion and carbon loss was observed in the watersheds, along with increased water retention. Although the study only reveals the outcomes for one year, the impact of the interventions is significant in the watersheds. Appropriate soil and water conservation measures need to be applied in the region, depending on the topography and other aspects of the watershed.

An in-depth analysis of the long-term impacts of different interventions requires prolonged monitoring and assessment of soil and carbon dynamics to capture seasonal and interannual variations for a more robust understanding of individual conservation measures. Another interesting impact assessment in the longer term would be assessing the impact on biodiversity health within the watershed and its subsequent effects on ecosystem health. As the Nature Positive initiative transitions into the Multi-Functional Landscapes Science Program, this study holds immense potential in investigating various land-use practices contributing to carbon sequestration across diverse land uses.