Studies were conducted to identify all the flood-prone areas in Asaba, Warri, Effurun, and environs, all in Delta State of Nigeria.

These studies were to help develop efficient and effective flood water control measures that would safely convey run-off from the streets to the natural watercourses and rivers without loss of lives and property.

The major objectives of the study were:

1. To identify the root cause(s) of flooding in Asaba, Warri, Effurun, and environs.
2. To provide primary drainage channels that would incorporate the existing and new secondary and tertiary drains for efficient and effective evacuation of the floodwater from the environment to the natural watercourses.
3. To make the natural watercourses efficient by desilting and removal of obstructions on flow paths.

Asaba, Warri, Effurun, and environs are viewed as hydrological basins that drain to the major Rivers (Niger and Warri) within their localities. These basins were broken into catchments using existing road networks for delineation as boundaries.

In the case of Asaba, the absence of water bodies limited the design approach to nature-based types, such as valleys, streams, and rivers that are tributaries to the River Niger.

But in the case of Warri and Effurun, the catchment areas contain lots of water bodies (swamps) and natural watercourses, which serve as the receiving basins for floodwater evacuation from the environment.

The delineation with existing road networks into catchment areas made the application of the Rational Formula and the Hydrological Analysis convenient.

Studies were conducted over the entire flood-prone areas, valleys, natural watercourses, swamps, and rivers, including existing drains in Asaba, Warri, Effurun, and environs.

The outcome of these studies is properly captured in my next post, Findings and Observations in Flood-prone Areas of Delta State, Nigeria.