Project context and challenge
The Msimbazi River basin covers a large part of Dar es Salaam. It combines some of the fastest informal urban growth in Africa with major roads and infrastructure, a patchwork of land uses and serious sanitation and solid waste problems. Flash floods are becoming more frequent and more severe, regularly cutting off the city centre and putting thousands of residents at risk. In the Jangwani valley, floods regularly block Morogoro Road and the Bus Rapid Transit depot.
These problems are closely linked and involve many parties, from national ministries and city authorities to local neighbourhood leaders and residents. Solving them requires more than an engineering plan: it calls for a shared vision that people understand and support. The World Bank therefore commissioned a participatory design process, led by Ecorys, to develop together with all stakeholders a strategic framework for the entire basin and a detailed plan for the lower basin.
CDR’s approach and contribution
Over about six months, two stakeholder workshops and six design charrettes brought together government agencies, experts and communities, including the chairpersons of the 16 neighbourhoods in the lower basin. Charrettes are intensive, interactive design sessions in which participants work around the table on maps and plans, making them well suited to complex issues that combine social, technical and environmental aspects.
CDR facilitated the sessions and provided the technical backbone of the process: GIS analysis and mapping, river engineering, hydraulic modelling support, design alternatives and conceptual designs for flood mitigation measures. Each design step was tested with the flood model and the results were explained to participants, so that everyone could see how choices affected flood safety.
Between the charrettes, CDR and its partners translated the input into spatial alternatives. These were discussed and refined with participants, combined into a preferred alternative and finally worked out into a detailed plan for the lower basin.
Step by step, the participants agreed on ten strategic directions, ranging from making room for ecosystems, retention and flood protection to resettlement in safe locations, better water quality, solid waste management, a new city park and good governance.
Result
The process resulted in the Msimbazi Opportunity Plan, a blueprint for turning the basin from a hazard into a showcase of urban resilience. For the lower basin, the detailed plan combines a city park, wetlands, mangrove forest and raised terraces for safe urban development, with enough space to rehouse households living in flood-prone areas.
The plan received broad commitment from stakeholders and laid the foundation for follow-up investments in the Msimbazi basin, including the Lower Msimbazi Upgrading Project.
