During 2012 and 2013, Watershed Management Group led a collaborative process between the City of Tucson Department of Transportation and many other stakeholders to develop a Green Streets policy. The policy, passed unanimously by Tucson’s Mayor and Council in May of 2013, requires that stormwater-harvesting features, such as vegetated streetside basins, be integrated into all publicly-funded roadway development and re-development projects. These features will be included from the beginning of the design process in order to ensure their effectiveness.
We already know how to design roadways to promote water conservation and enhance our urban forest. Now, the City of Tucson has taken the necessary steps to ensure that new projects integrate this knowledge in order to promote a more livable Tucson and a healthy urban watershed.
This policy will:
- Grow more shade trees—our “urban forest”
The recommended canopy cover for arid cities like Tucson is between 25-30%; Tucson’s canopy cover is estimated to be between approximately 5%. This policy will require 25% canopy coverage along new roadways.
- Cool our streets
Trees and shade reduce urban heat island effect by shading and cooling streets and buildings. Our urban spaces are considerably hotter than the surrounding natural environment due to streets, buildings, parking lots, and other impervious surfaces that absorb heat and then radiate it back into the environment. Urban heat island effect has numerous negative impacts on public health and quality of life.
- Conserve water
While it’s critical that we plant trees, it’s also critical that those trees don’t cause additional stress on our scarce potable water resources (sourced from our aquifer and the Colorado River). That’s why stormwater harvesting is so important – the policy requires that vegetation planted be able to survive on stormwater capture alone. It also reduces flooding along city streets because water is captured close to where it falls.
- Support wildlife
Trees and other vegetation provide urban habitat for many native species. Tucson’s abundant urban wildlife provides a sense of place, a connection to nature, and attracts tourists.
- Clean our air and water
Trees enhance air quality by filtering pollution. Green infrastructure treats stormwater pollution naturally by filtering pollutants, from motor oil to pet waste out of stormwater.
- Beautify our city
Trees increase real estate value, enhance community pride, and provide beautification and sense of place rooted in our Sonoran Desert environment. Shaded roads and sidewalks are much more appealing for bicyclists and pedestrians.