Study Area: Hydrology and Drainage

Hydrology and drainage are important natural processes centered on how water moves across the surface of the island and where it ends up. Without proper study, infrastructure projects have the potential to disrupt this natural flow.

Hydrology and drainage are important natural processes centered on how water moves across the surface of the island and where it ends up. Without proper study, infrastructure projects have the potential to disrupt this natural flow.

This section of the EIA focuses on establishing baseline hydrology and drainage conditions, assessing the potential impacts of the EWA, and proposing mitigation and minimization measures. The focus is on maintaining the natural drainage of the island while meeting current and future transportation needs. Because sea-level rise and storm flooding are a large concern for the Cayman Islands, establishing resiliency to climate change is an important part of the hydrology and drainage study.

Key aspects:

  • Prior storms and flooding conditions, as well as field evaluation of the hydrological processes on the island, help inform this portion of the study
  • Studies for hydrology include a rainfall analysis, water budget analysis for the Central Mangrove Wetland, surge analysis, wave overtopping analysis, and a hydrology and hydraulic analysis

Understanding the study

Hydrology and drainage are important processes on Grand Cayman and within the EWA EIA study area. These processes support the health and safety of residents and natural resources.

The project’s study of hydrology and drainage examines the relationship between road construction and surface water run-off movement across the island, considering whether construction of the road would significantly impact natural flow patterns and how to mitigate for those effects.

The EIA also considers what design conditions need to be satisfied to minimize flooding and inundation from the roadway during heavy rainfall and/or severe storm events and potential measures to reduce stormwater runoff pollution during the construction and operation phases of the roadway.

Flooding on Bodden Town Road during July 2023 rainfall event.

Here’s what we are doing

Hydrology and Drainage in action.