Sediment management

The challenge

Over the lifetime of a hydropower dam, sediment will be trapped behind the infrastructure and deposited in the reservoir.

Dams are traditionally designed to provide enough reservoir storage to offset at least 50 to 100 years of sedimentation, which is caused by natural erosion and activities such as construction, deforestation and agriculture.

As the reservoir accumulates sediment, its storage capacity will decrease. Sedimentation also causes operational and maintenance challenges, resulting in the obstruction of water intake, the abrasion of mechanical equipment, and reductions in power supply.

Downstream environmental impacts can include increased erosion, reduction in nutrient deposits inland and retreat of deltas. Changes in sedimentation due to climate change can also compromise the performance of a facility.

Effective sediment management is essential for ensuring storage capacity for water and renewable energy supply, and for protecting the health of the ecosystems that a river system supports.

Our strategy and action

IHA is building awareness and disseminating knowledge on successful sediment management strategies.

Working in close collaboration with a group of industry experts and partner organisations, we are identifying and sharing good practices on managing sediment in a variety of geographies and environments.

In December 2016, we partnered with the World Bank on a project to study and document strategies and case studies across the world. These resources are now available on a new Hydropower Sediment Management Knowledge Hub.

In our engagement with IHA members, emphasis is always given to the adoption of sustainable practices: both at the initial stages of hydropower development and throughout the operation of a project.

Throughout 2018, we will continue to provide a platform for the sharing of strategies and resources to minimise the impacts of sedimentation and extend the life of hydropower facilities and reservoirs.

Recent activities

In January 2017, we began work on a project funded by the South Asia Water Initiative - a partnership between the World Bank and the governments of UK, Australia and Norway - to document sediment management strategies and case studies around the world.

In May 2017, at the World Hydropower Congress, we convened a workshop of members and stakeholders to discuss success stories and lessons learned in sediment management. In two other events, initiatives to reduce upstream erosion were introduced. They included cloud-forest conservation mechanisms and watershed management in the Ethiopian highlands.

In September 2017, a beta version of the Hydropower Sediment Management Knowledge Hub was made accessible online and later, in November, was showcased at a hydropower sector conference in Medellin, Colombia.

In December 2017, the Hydropower Sediment Management Knowledge Hub was launched with 18 case studies from 15 countries in Africa, Asia, Europe, Central and South America and the Pacific. Downloadable resources include the RESCON2 tool to help developers and operators choose an appropriate sediment management strategy.