UNTAPPED POTENTIAL FOR RAINWATER HARVESTING: “We need to elevate the role of stormwater capture across the country as part of the toolbox to help alleviate the increasing stress in our water supplies,” stated Bruk Berhanu, Ph.D., a senior researcher for the Pacific Institute
Note to Reader:
Long seen as a nuisance to be gotten rid of as quickly as possible, urban stormwater increasingly is being viewed as a resource. Although the concept of capturing and using urban stormwater has gained attention in recent years, the full promise of this approach is far from being realized.
This is the assessment of a new report released in early March by global water think tank the Pacific Institute and 2NDNATURE Software Inc., a provider of stormwater management software. Titled Untapped Potential: An Assessment of Urban Stormwater Runoff Potential in the United States, the report finds that U.S. cities, particularly those in coastal regions, could benefit in multiple ways by making greater use of stormwater.
‘Vast opportunity’: Captured stormwater could be urban boon
“Urban communities across the United States face a range of water challenges. These include intensifying impacts of flooding and drought, water scarcity risks, constraints on traditional water supplies facing peak water limits, and water pollution. Novel approaches are needed to address these challenges and improve long-term water resilience,” state the report authors.
Why capture rain where it falls
“Stormwater capture offers a promising tool. It can help close the gap between water supply and demand by augmenting and diversifying water supplies. It can also mitigate impacts on communities from intensifying flooding and drought and reduce water pollution.”
“Stormwater capture also offers additional co-benefits, including greening communities and cooling urbanized areas. However, greater uptake of stormwater capture is hindered by a lack of comprehensive data on the amount of stormwater available.”
Volumetric potential of urban runoff
“This assessment from the Pacific Institute, in partnership with 2NDNATURE, quantifies the volumetric potential of urban stormwater runoff in the United States. This groundbreaking report estimates U.S. Urban Areas have the potential to generate 59.5 million acre-feet of stormwater runoff annually on average.”
“This is equivalent to an annual average of more than 53 billion gallons per day. It equals 93% of municipal and industrial water withdrawals in 2015, the most recent year with available data.”
Opportunities in coastal areas
“Notably, coastal areas offer outsized opportunities for stormwater capture and use. While coastal subbasins constitute just 12% of urban land area, they generate 37% (21.9 million AFY) of the national stormwater runoff potential. Capturing runoff in coastal subbasins could have fewer adverse impacts on downstream users and can also improve water quality in coastal waterways.”
“Despite the potential, capturing all available stormwater is not always feasible or desirable due to various challenges, including legal constraints and ecological considerations. The report recommends strategies tailored for different regions, emphasizing the need for detailed local assessments.”
Now what
“The report calls for national guidance to streamline stormwater capture and use, encouraging regional collaboration, and expanding applications for stormwater use. It also identifies the need for more funding and financial mechanisms to support stormwater projects, increased integration of water and non-water benefits into water management strategies, and public-private partnerships to leverage stormwater capture’s full potential.”
To Learn More:
Download a copy of the Executive Summary for Untapped Potential: An Assessment of Urban Stormwater Runoff Potential in the United States.
