Home > Press Release > WMG report shows rain gardens can reduce flooding and benefit Tucson neighborhoods

WMG report shows rain gardens can reduce flooding and benefit Tucson neighborhoods

Release Date:

August 12, 2015

Media contact: Kieran Sikdar 520-396-3266 x3 or ksikdar@watershedmg.org
Rain gardens can reduce flooding and benefit Tucson neighborhoods

Watershed Management Group’s latest study found that adoption of green infrastructure – water harvesting practices – can reduce flooding from large storms while benefiting Tucson neighborhoods by promoting shade, beauty, traffic calming, and property values.
A recent study released by Tucson non-profit Watershed Management Group (WMG) found that water harvesting can reduce major flooding while creating $2 – 4 of community benefits in return for every $1 invested.

WMG worked with the Pima County Regional Flood Control District (PCRFCD) to understand the potential for water harvesting to cost effectively address flooding challenges in the Airport Wash area. The Airport Wash study area, located between Drexel/Los Reales and I-19/Tucson Airport, experiences regular and chronic flooding. A monsoon rain in August 2010 flooded businesses and churches and made streets impassable.

WMG identified water-harvesting opportunities for streets, homes, businesses, schools, and churches within the Airport Wash area. Two water-harvesting scenarios were developed and evaluated for both flood reduction and cost-benefit effectiveness. The study shows results from scenarios where 10% and 25% of the private and public properties implement water-harvesting features.

Results from modeling show water harvesting can have a significant impact on both large and small rain storms. For example, water harvesting resulted in a reduction in peak flooding of a 100-year 3-hour rain event by 24% in the Valencia watershed. Peak flow conditions decreased from 10% to 24% based on the 25% water-harvesting adoption scenario.

Since every $1 invested in water-harvesting green infrastructure results in $2 – 4 in community benefit, retrofitting landscapes with rain gardens and curb cuts is well worth the cost. Roadway redevelopment following the City of Tucson’s Green Streets Active Practice Guidelines (Green Streets Policy) also provides benefits that outweigh investment costs, a $2.10 return on investment. The Green Streets Policy requires all new and redeveloped city streets to incorporate streetside water-harvesting features to capture stormwater and support shade trees and other landscaping. This policy ensures our streets capture the rains for our benefit instead of contributing to flooding.
In addition to flood reduction, rain gardens help cool our city by growing an urban forest that can shade our streets and homes. A shadier, more forested city increases property value, reduces energy needs related to cooling, and improves our air quality. Rain gardens also reduce irrigation needs with potable water and help process stormwater pollution to keep our washes and creeks cleaner.

The study confirms that Tucson’s innovative water-harvesting policies, including Tucson Water’s rainwater harvesting rebate, the City’s commercial rainwater harvesting ordinance, and the Green Streets Policy, are valuable long-term investments in our city infrastructure. These policies help to facilitate the adoption of rain gardens and begin managing stormwater as a resource across the Tucson basin.

For the full report and other information on green infrastructure, visit our website: watershedmg.org/green-streets/resources#airport-wash or contact Kieran Sikdar, ksikdar@watershedmg.org.