Nature-based solutions in Tanzania’s Mindu Dam Catchment for water security

In Morogoro, Tanzania, the Mindu Dam plays a critical role in providing drinking water to over 75% of the city’s population. However, increasing pressures on soils and the watershed—such as deforestation, land degradation, and erosion—combined with the impacts of climate change, threaten the long-term reliability of this vital water source.

To address these challenges, World Waternet, the Wami Ruvu Basin Water Board (WRBWB), and drinking water utility MORUWASA are piloting an Integrated Water Resources Management (IWRM) approach rooted in nature, using nature-based solutions (NbS). Supported by the Dutch NWB Fund and the Climate Adaptation Fund of the WaterWorX programme, the project “Piloting Nature-Based Interventions along the Ngerengere River” aims to restore and protect the Mindu Dam Catchment Area (MDCA) by combining ecological restoration with community engagement, market development, and participatory monitoring.

Nature-based solutions offer a sustainable and cost-effective way to strengthen ecosystem functions, while supporting local livelihoods. Interventions such as agroforestry, riverbank restoration, and reforestation not only reduce erosion and sedimentation, but also improve water retention capacity, enhance biodiversity, and strengthen the income for farmers.

Agroforestry demo plots

In 2024, the project team established ten agroforestry demonstration plots in the upstream villages of Mnyanza and Tangeni. These plots showcase various systems—such as fruit, banana, spice, and riparian agroforestry—designed to stabilize riverbanks, reduce erosion, and create higher income opportunities for farmers. Participating farmers, supported by agricultural extension officers and trainers of the local NGO Sustainable Agriculture Tanzania (SAT), received hands-on training both in the field and through structured sessions, including tailored agroforestry designs and planting demonstrations.

To ensure their full functionality, a targeted “gap filling” effort was conducted in early 2025, which included the supply of additional seedlings, updates to planting schemes, and follow-up farmer support.

Tree nurseries

Building on this success, the project has now started the establishment of five community-based tree nurseries in Mnyanza, Tangeni, and Mzinga. These nurseries—set up in collaboration with Sustainable Agriculture Tanzania (SAT)—are expected to produce more than 75,000 planting materials, benefiting over 240 farmers. The nurseries will serve as a key engine for scaling up restoration efforts throughout the catchment while providing lasting economic benefits to the local communities.

Strengthening market access

While agroforestry creates ecological benefits, the economic incentive is equally important for long-term adoption. To this end, a market study was conducted in beginning of 2025 with support from the NWB Fund’s Community of Practice on Nature Based Solutions. The study explored the demand for fruits and spices produced in Morogoro, identifying the most promising crops for smallholders in both domestic and export markets. The results are now being used to refine nursery crop selection and guide development of value chains and business models together with local stakeholders.

Strengthening monitoring for long term impact

To support data-driven decision-making, the project is also launching a new monitoring station along the Ngerengere River. This upgraded hydro-meteorological and water quality station will provide real-time data on streamflow, rainfall, and key water quality parameters. It will allow the project team to measure the direct impact of NbS interventions—such as agroforestry and check dams—on water retention, sedimentation, and overall ecosystem health.

The station, located at Konga A, will be complemented by multiple sampling points along the river and upgraded weather equipment at the Mindu Dam. Monitoring results will guide adaptive management and feed into a long-term monitoring framework for the entire MDCA. The installation is scheduled for Q2 2025.

A participatory and integrated approach

The participatory approach forms the core of the project. Activities—such as tree nurseries, agroforestry demo plots, communication strategies and monitoring stations—are jointly designed and developed with local partners and communities. These are documented in concept notes, which include technical descriptions, expected outcomes, and risk mitigation strategies, and serve as flexible planning tools throughout implementation. This approach ensures that all interventions are well-aligned with local priorities, knowledge, and conditions, and are carried out in close collaboration with the people who live and work in the landscape.

The project is also implementing a Participatory Monitoring Framework to track environmental and social impact over time. Using tools like FarmTree, QField, and satellite imagery, data is collected on soil erosion, water infiltration, shade levels, biodiversity, and socio-economic indicators. These insights support adaptive management and help build a case for future investment and scaling of interventions.

Building local stewardship

The project strongly emphasizes local ownership by working closely with institutions such as Water User Associations (WUAs), Village Agricultural Extension Officers (VAEOs), and school environmental clubs. These groups play a key role in mobilizing communities, maintaining field activities, and ensuring that knowledge is shared and applied locally. All training and technical assistance are provided in collaboration with experienced Tanzanian partners, including Sustainable Agriculture Tanzania (SAT) and Sokoine University of Agriculture (SUA). Together, they help build long-term capacity in areas such as agroforestry practices, nursery management, participatory monitoring, and sustainable land use planning.

Toward a climate-resilient catchment

The broader ambition is to create a climate-resilient Mindu Dam Catchment Area (MDCA), where human activities and natural systems are balanced. This entails improved water availability, restored ecosystems, and sustainable land use—all while generating income opportunities for local communities.

The project will run until June 2026, and several impactful activities are planned in the coming period. These include the construction of a cattle trough in Sanga Sanga village and two check dams to reduce erosion and enhance water retention. In addition, a comprehensive communication and awareness component will be implemented, including the production of two documentaries—one aimed at local communities and one targeting institutional stakeholders and potential funders—to share experiences, results, and lessons from the pilot.

Beyond the pilot interventions, the project team—together with Wami Ruvu Basin Water Board and MORUWASA—intends to develop a financeable landscape plan, supported by a dedicated finance facility. This facility, potentially structured as a water fund, would aim to mobilize long-term blended financing to sustain and scale up nature-based solutions across the full catchment area.

By combining technical expertise with local leadership, and linking on-the-ground results with investment-readiness, the initiative offers a scalable model for integrated watershed restoration. The strong partnership between MORUWASA, WRBWB, and World Waternet (through WaterWorX), with support from the NWB Fund and the Climate Adaptation Fund of WaterWorX, plays a vital role in making this kind of long-term, system-based transformation possible.