This project aimed to evaluate the impact of community stewardship on the performance of Green Rainwater Infrastructure (GRI) assets in Vancouver. Our goal was to answer a critical question for the City’s Green Infrastructure Team: What added value does community stewardship bring to the performance of Green Rainwater Infrastructure?
We analyzed condition data from 106 rain gardens between 2022 and 2024, comparing sites with active volunteer stewardship against those without. Using R and Tableau, we calculated performance trends by measuring the change in condition scores over time (where a lower score indicates better condition).
Our analysis uncovered a counter-intuitive trend: sites under active stewardship were more than twice as likely to decline in condition as non-stewarded sites. Conversely, non-stewarded sites, which started in worse condition, saw better condition scores.
Stewards successfully improved vegetation, inlets, and planting beds, meaning site functionality was improving in the majority of subcomponents. But, condition scores still, on average, were worse for stewarded sites. This means subcomponent scores are weight differently when factored into condition scores.

Our recommendations are to audit how condition scores are measured and weight, scale active subcomponent monitoring and practices across non-stewarded sites, and roll out stewardship to sites with worse final condition scores.