10. Super Use Case


The Government of Saint Lucia has recognized the importance of a national integrated watershed management plan to ensure sustainable use of its water resources, because the country depends primarily on surface water for its potable, agricultural, commercial and industrial needs. With increasing demands due to increasing socio-economic development, and competing uses among the various sectors, this water supply is highly vulnerable. Some watersheds experience multiple environmental problems that are interrelated. One of the most re-occurring problems are flash floods from tropical storms and hurricanes, that affect most watersheds once in 5 year if not more, leading to loss of lives and damage to houses and infrastructure. In spite of the extremeness of these weather events, it is often possible to mitigate the effects in a catchment, usually with a mixture of land use planning and engineering. Added to these challenges are the impacts of climate change, which are expected to reduce water quantity and quality within rivers.

Other problems are also part of integrated watershed management: loss of productivity, guarding ecosystem services, salinization close to the sea etc. However, floods and drought cause very different processes for different stakeholders, often needing different analysis techniques and different solutions and strategies. This super-use case focuses on flash floods only, fitting within the context of the CHARIM project. Nevertheless there are two clear links between flash floods and other processes: upstream water harvesting can be a solution to prevent flash floods, while this water becomes available for other uses (e.g. agriculture), and soil erosion often leads to blockage of the drainage system during storm events, leading to flooding. Therefore prevention of soil erosion (and even landslides) can be a necessary tactic in watershed management. However, soil erosion and landslides are not part of this report and analysis.

The development of the IWRM plans is part of the St. Lucia Disaster Vulnerability Reduction Project, supported by the World Bank. It was therefore suggested that the development of the CHARIM "super use-case" - one of the CHARIM deliverables - could contribute by informing the creation of watershed management plans with flood hazard information. The target organization is the St. Lucia Water Resource Management Agency (WRMA) that has been charged with the development of the watershed management plans.


  • The first objective is to develop a practical approach for flood modeling with existing information complemented with limited data collection for one watershed - which can be replicated in other watersheds. This watershed is used as an example case study, to illustrate the steps that have to be taken to do a model analysis for integrated watershed management.
  • The second objective is to increase the capacity at WRMA to carry out/plan hydrological and hydraulic analyses for flood modeling using a hands-on approach with the above mentioned flood model.

Download the materials for the Super Use Case: