Sustainable management of Mindu Dam catchment in Tanzania

The Wami-Ruvu Basin Water Board (WRBWB), water utility MORUWASA and World Waternet have been working together for several years to develop a sustainable approach to managing the Mindu Dam catchment, the main source of drinking water for the city of Morogoro in Tanzania. Erosion, sedimentation and increasing pressure on land and water resources demonstrate that protecting this vital water source requires more than investments in infrastructure alone. The surrounding landscape, from which the water originates, also needs protection and restoration.

We are therefore working towards a broader approach to sustainable watershed management across the entire Mindu catchment. The ambition is to gradually develop a Mindu Watershed Investment Programme (MWIP), with a Water Fund as a potential financing mechanism through which different stakeholders can jointly invest in restoring and protecting the watershed.

To support this ambition, we have established a pilot project along the Ngerengere River, one of five rivers flowing into Mindu Dam. The pilot represents the first practical step towards achieving this broader ambition. It provides an opportunity to gain experience with nature-based solutions, collaborate with local communities and identify which approaches offer the greatest potential for replication along the other four rivers in the catchment.

The Contribution of the NWB Fonds

Within the broader pilot project, the NWB Fonds has played a specific role. While other funding has primarily focused on implementing measures in the field, the NWB Fonds has supported the activities needed to successfully implement and scale up nature-based solutions. These include community engagement, technical assessment of interventions, testing agroforestry systems and developing a participatory monitoring framework.

Working with Local Communities to Develop Solutions

A key principle of the pilot is that sustainable watershed management can only succeed when local communities are actively involved. From the outset, farmers, village communities, local authorities, Water User Associations and other partners have therefore participated in the development and implementation of activities. Village meetings, training sessions, exchange visits and demonstration activities have helped raise awareness and strengthen local engagement.

This approach has not only encouraged active participation in the various activities but has also strengthened local organisations. One example is the establishment of UWAMAMI, a community-based organisation that will play an important role in the future management of activities within the watershed.

Agroforestry as a Practical Learning Environment

Agroforestry demonstration plots have played a central role in the pilot. Working together with farmers, different agroforestry designs have been tested. The aim is to reduce erosion, improve water retention, enhance biodiversity and, at the same time, create new income opportunities for farmers.

The demonstration plots have provided valuable insights into how nature-based solutions work in practice. They enable farmers to exchange experiences while also serving as learning environments for partners involved in watershed restoration. Community tree nurseries have also been established to increase the availability of planting material and further strengthen local engagement.

The pilot has confirmed that successful watershed restoration depends on more than technical solutions alone. Access to markets, farmers' incomes, training, local organisation and long-term support have also proven to be important conditions for success. These insights will be highly valuable for future projects in other parts of the Mindu catchment.

Measuring What Works

One of the project's most important achievements is the development of a participatory monitoring framework. Together with farmers, Water User Associations, local authorities and technical partners, indicators have been developed to track the progress and impacts of nature-based solutions. These indicators cover both the implementation of interventions and their effects on water management, soil erosion, biodiversity and local incomes.

The monitoring framework has been tested in practice and further refined. Water User Associations have received training in data collection, while local partners have gained experience in processing, analysing and communicating results. To make the results accessible and useful to different stakeholders, a dashboard has been developed. It combines field data collected by farmers and local partners with analyses generated by FarmTree's Watershed Reforestation Tool.

This enables partners not only to monitor what is happening on the ground but also to better assess the potential long-term impacts of nature-based solutions on water resources, soil, biodiversity and local incomes. The dashboard thus supports monitoring, decision-making and the further development of investment proposals for the Mindu catchment.

From Pilot Project to Investment Programme

Perhaps the most valuable outcome of the Ngerengere pilot is the knowledge gained. Testing interventions in practice provides insights into what works, which conditions are necessary for successful implementation and how results can be demonstrated. These lessons are already being used to prepare follow-up activities along another river in the Mindu catchment.

The experiences gained through the pilot also contribute directly to the further development of the Mindu Watershed Investment Programme (MWIP). This involves not only scaling up interventions but also establishing the institutional, organisational and financial conditions needed to enable sustainable watershed management.