Through the ‘Green Roads for Water’ program Makueni County is at the forefront of utilizing existing and new road infrastructure to capture and manage rainfall and surface runoff effectively. This approach not only enhances water availability but also mitigates rain-related damages in the area.
As part of the Drain2Gain project, implemented by MetaMeta and the Makueni County Government, a recent study focused on enhancing road water harvesting techniques in Mbooni Sub-County. The study employed an analytical hierarchy process framework to select and rank several biophysical and socio-economic criteria to determine the most suitable sites for road water harvesting. This method helped create detailed suitability maps, pinpointing optimal locations for various water harvesting structures such as mitre drains, farm ponds, and sand dams. The results of this study showed that this framework has the potential to be an effective tool for preliminary site evaluation, with the ability to incorporate both local and expert knowledge.
To quantify the effectiveness of mitre drains in capturing road runoff, a comparative analysis using the Storm Water Management Model was used. The findings revealed that mitre drains could reduce runoff losses by 62% during a 6-hour, 70 mm storm event, demonstrating their potential to capture substantial amounts of water. However, further calibration and validation was needed to make definitive conclusions on the exact volumes of water captured.
Despite its current limitations, the framework could provide a tool that is able to give theoretical backing for the effectiveness of implementations. Preliminary site evaluation has the potential to streamline the process of selecting suitable locations for water harvesting, reducing the time and effort required for fieldwork and leading to more efficient design and management of water resources.
For more detailed information, you can access the full report of this study here. This study forms the thesis of Joram Niemans, conducted as part of his studies at Vrije Universiteit Amsterdam.
Last modified: July 12, 2024