Meeting Multiple Objectives with Flood Risk Management

Water and sanitation are intrinsically linked to flood risk management, particularly in urban areas. When sewage and drainage infrastructure is unable to keep up with population growth, flood risk is increased; flood risk can also be compounded when outflows, drains and waterways are blocked by debris or encroached upon or occupied by informal settlements. Such a situation often causes average rainfall events to result in localized flooding and decreased water quality.

Many natural and nature-based flood risk management techniques, however, can also improve water quality, in turn benefiting community public health, because pollutants and trash are either removed from the water source or are partially filtered out as the water moves through vegetation and soil. The two examples below describe how flood risk management and disaster risk reduction projects can meet such multiple objectives as promoting solid waste management, clearing waterways of debris, managing upstream flow, and the co-benefits of improved public health and improved water quality. Using a watershed approach to flood risk reduction can also reduce the devastating human and economic losses associated with repeat flooding, particularly at a household level, as evidenced in the Bamako, Mali, case.

Bamako, Mali

In 1999, Bamako, the capital city of Mali, experienced devastating flash floods that were responsible for a significant loss of life, property and the livelihoods of several thousand families. Contributing to the floods was the fact that infrastructure investments and waste management services had been unable to keep pace with the approximate 500% population growth experienced by the city over the previous 40 years. The city’s waterways and drainage systems deteriorated and became obstructed by trash and debris during this period.

In response to the floods, the USAID Office of US Foreign Disaster Assistance (OFDA) funded a project by the Action Contre La Faim (ACF) with the objective to reduce flood risk, but also to improve watershed and solid waste management, livelihood generation, and public health and sanitation. The project objectives also included implementing flood risk reduction techniques, education, training, microfinance and stakeholder involvement.

Working with the commune (district), local governments and community members, ACF held trainings and distributed information on improving solid waste disposal practices and cleaning up refuse in neighborhoods. ACF also hosted tea-talks, theater presentations, and primary and secondary school presentations to increase community awareness about the connection between waste management and flooding, and to introduce concepts of composting (for waste reduction) and rainwater harvesting (to reduce stormwater runoff). ACF also offered literacy training for women in the commune to encourage their involvement.

The project addressed the causes of flooding both upstream and downstream. Working with the community, ACF restored natural drainage paths, installed soakpits (narrow trenches to capture runoff), and implemented other upstream diversion techniques. In the urbanized areas, ACF worked with the local government to develop a replicable, low-cost refuse collection and removal service and landfill operations. Throughout project design and implementation, ACF held stakeholder meetings, inviting representatives from the Regional Division of Sanitation and Pollution and Nuisance Control (DRACPN), local associations, research groups and commune residents.

To facilitate a reliable refuse collection service, ACF developed a micro-finance program component, and collection teams from within the commune organized to provide refuse collection. The teams received training and used small diesel tractors with locally made trailers, which replaced donkey-drawn carts, to collect refuse along eight routes. This service provided income for unemployed youth and became cost effective as collection fees were generated. The refuse was brought to a landfill operated by ACF and compost was collected and stored for fertilizer.

By promoting solid waste management services and clearing the waterways of debris, this project successfully reduced flood risk in part of Bamako. The reduction in urban waste also improved water quality and reduced the incidence of mosquito- and water-borne illness in the area by 33%-40%, improving public health outcomes. At the household level, the project demonstrated the net benefit of investments in flood risk reduction in improving long-term development outcomes. OFDA has estimated that for every US$1 invested in this project in 1998, a “savings” of approximately US$46 was generated during the following rainy seasons. The benefits of this type of investment have been compounded by the fact that there have not been any widespread flood losses since. For a household this has meant an annual savings of US$426, more than half the average income, which could be spent on household needs rather than disaster rebuilding and recovery.

This case study has been adapted from the following source:

Charles A. Setchell, “Multi-Sector Disaster Risk Reduction as a Sustainable Development Template: The Bamako Flood Hazard Mitigation Project,” Monday Developments Magazine 26, no. 4 (April 2008): 18-19.