What is it about?

This study aimed at estimating the reduction in peak flow and flood volume when rainwater harvesting systems are theoretically installed to all of the buildings found within the study area with the help of ARCGIS and HEC-HMS. Only a few studies have explored on the use of HEC-HMS in modelling the effect of the RTRWHS on a large scale basis. The results were validated in two ways, one by comparing the ARC-GIS generated curve number with that of the calibrated one for several sub-catchments and second, by comparing the total runoff mitigated to the total volume of theoretically installed water tanks to all the buildings in the study area.

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Why is it important?

This study is timely because it helps the stakeholders reason why the state declared a certain minimum and maximum value to the rainwater tanks to be installed for future or on-going building construction. The state policy has declared that the tank sizes to be installed should be within 0.5-4 cubic meters for domestic households, and 1-7 cubic meters for other building occupancy types. It also gives water engineers an idea of how much water can be mitigated when RTRWHS are in place which will greatly help in the inception, design and implementation of a more effective flood mitigating structure in the future.

Perspectives

Writing this article was an exciting task for a newbie researcher like me. This would not have been possible without the help of an experienced hydrologist, my adviser. I hope that this research pave the way for the makers of HEC-HMS to put in an additional feature to their software that will make modelling of the effect of rainwater tanks easier and yield better estimation results.

Kathrina Marie Borgonia
University of San Carlos

Read the Original

This page is a summary of: Estimation of the reduction in flood peak and flood volume due to rooftop rainwater harvesting for nonpotable use, January 2020, American Institute of Physics,
DOI: 10.1063/5.0014516.
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