How Active Rainwater Harvesting may help Reduce Nuisance Flooding: Flood Analysis and Social Barriers to Adoption

As urbanization continues to expand, fewer pervious surfaces are available to help reduce stormwater runoff from rainfall. The impacts of urbanization are becoming evident through sunny day flooding - flooding that occurs in areas not designated by the Federal Emergency Management Agency (FEMA) as flood zones. Nevertheless, water accumulates in low-lying areas and compromises street intersections and other parts of neighborhoods. Some methods can help alleviate the impacts of unexpected heavy rains, such as passive and active rainwater harvesting. As a pilot study, in a selected area in the northeast of El Paso, the level of adoption (e.g., what percentage of people may be able to harvest rain), feasibility (appropriate structure, sufficient land), and land cover (e.g., turf, xeriscaping) were evaluated. The GIS approach was employed to generate a land cover map to obtain the necessary parameters for SCS calculations. The SCS curve number was utilized to account for losses due to infiltration. RWH potential of roofs as catchment areas were calculated and in conjunction with the data obtained from GIS, a rainfall-runoff model was developed in HEC-HMS to simulate different volumes for frequency storms ranging from 1-Year to 500-Year. The comparison of the results from the HEC-HMS model and the storage capacity roof indicates that for the most common storms, RWH storage exceeds the volume produced during those storms. In general, the reduction of water that can be kept off the streets is significant even in extreme storm scenarios. Overall, the results are indicative that RWH can help alleviate sunny day flooding. In addition, we explored the community\u27s attitude and understanding of RWH and climate change and their opinions on the impact, if any, they believe has been identified in the region. The views and knowledge of the residents about rainwater harvesting and climate change must be considered to fully gauge the barriers that could present themselves in the case of implementation