September 16, 2016

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Hassan Tavakol Published in ASCE's Journal of Sustainable Water in the Built Environment

Hassan Tavakol (California) published a technical paper entitled "Performance and Cost-Based Comparison of Green and Gray Infrastructure to Control Combined Sewer Overflows" in the Journal of Sustainable Water in the Built Environment, Volume 2, Issue 2, May 2016. His co-authors were Steven J. Burian, Jay Devkota, and Defne Apul.

The Journal of Sustainable Water in the Built Environment is published by The Environmental & Water Resources Institute, the American Society of Civil Engineer's (ASCE) technical resource for environmental and water-related issues. The journal presents activity and research developments in water issues, challenges, and opportunities throughout the developed landscape. The scope covers sustainable stormwater management and broader water systems interactions. Subjects include urban stormwater quantity, quality, hydrology, characterization, treatability, and impacts; water harvesting; urban water ecosystem services; sustainable urban watershed management; urban streams; combined sewer overflow/stormwater interactions; urban energy/water interactions; lifecycle analysis; and related policy, implementation, and economics.


Rainwater harvesting (RWH) is being used more often today as a water supply and stormwater management green infrastructure (GI). In recent years, GIs in urban water engineering have gained attention due to their lower lifecycle costs—in both implementation and operation phases—rather than traditional gray approaches. The research described in the present paper compared implementation of RWH systems to gray approaches previously designed as a part of the long-term control plan (LTCP) for combined sewer overflow (CSO) control in Toledo, Ohio. RWH scenarios in this study were defined based on different system capacities and release policies, and then combined gray and green scenarios were analyzed according to their hydrologic performance and cost. This study employed long-term continuous hydrologic and hydraulic (H&H) simulations as well as lifecycle cost (LCC) analysis techniques. The results showed that greening the LTCP via RWH could improve the lifecycle cost-effectiveness by 48%. The captured rainwater was considered to supply toilet flushing water demand in buildings.

More Information

For more information or to read the paper, visit Journal of Sustainable Water in the Built Environment
For more information about the Journal of Sustainable Water in the Built Environment, visit
For more information about ASCE's Environmental & Water Resources Institute, visit: ASCE
For more information on rainwater harvesting, contact Hassan Tavakol at This email address is being protected from spambots. You need JavaScript enabled to view it..