The soil checks out. It’s loose and permeable. What we found as we dug deeper, though, was hard layers several feet under. This limits the potential for rain gardens so cisterns look like better options for this site.
The Project’s Beginnings
The Holy Family Parish, a 2000 family parish, is working with Sustainable Seattle and Rain Dog Designs to install rain gardens, cisterns and other sustainable sites.
This provides an enormous opportunity for green infrastructure – especially with 30,000 square feet of roof and a significant amount of asphalt.
In June of 2013 Rain Dog Designs, Sustainable Seattle, and Holy Family Parish and School partnered up and developed a project proposal to submit to King Conservation District for support. With the grant awarded in November, this project had the support it needed to move forward.
Even before this grant was awarded, work on the project was underway. RainWise, Seattle Public Utilities, and Rain Dog Designs worked to develop the technical process required to implement such a project. This includes soil testing, ground water testing, high-flow infiltration testing, and a rain garden designed to manage a 100-year storm. As the project progresses, this process will become available.
The first step was testing the ground water level at the site as well as evaluating the soil of each of the locations selected for green infrastructure. With digs to 20 feet, the results were very positive! The infiltrative soils are expected to allow an infiltration of 2 inches per hour – and up to 12 inches per hour. The well, at 30 feet deep, shows a low groundwater level allowing a high volume of infiltration on site. These findings allowed the project to advance toward its current stages of infiltration testing, and, eventually, implementation and planting!
Implications and Impacts
This project is more than just your ordinary RainWise project. The bilingual Parish and School has the potential to catalyze multi-benefit large-scale projects throughout the RainWise basin:
·Partners are implementing a RainWise project for a roof of an unprecedented size of over 30,000 square feet, a process that includes the additional engineering requirements being developed.
·In addition to RainWise incentives earned, installations will also qualify for the Stormwater Credit Program. This will reduce the property’s $18,000 per year surface water fees by 13% to 36% in the long term.
·Sustainable Seattle works to gather community input and ensure these interests and needs are being addressed through the development of a Greening Team that provides input on outreach, design, and maintenance plans.
· The collaboration with the community has the potential to result in even more on-site projects, like an urban farm, energy efficiency for the buildings, and possibly a Depave event!
In addition, the project provides a vibrant source of education for the community and the on-site school. Sustainability Ambassadors is collaborating with teachers to incorporate the tangible project into the school’s curriculum, ultimately enabling students to be the caretakers of the gardens as well as the mouthpiece of the project.
The high-visibility of the project is allowing it to become a model for other RainWise projects. For many large-scale projects, there was no financial-incentive for installing green infrastructure features. This project will provide a guide to access financial incentives – all while developing community assets! In addition to talking with large sites about the potential for replication, the project will publish a step-by-step guide when the key components of the project are in place.
Help make this project the best it can be! The project’s design and any projects that come after will be driven by the Greening Team. We invite members of the parish, parents at the school, and residents of the surrounding community to participate in he planning.