https://resilient.mysticriver.org/
Check out the Mystic River website, and some of the data you can find there.
As well as some of the work they are doing.
https://resilient.mysticriver.org/our-work
The business case from "Building Community Resilience with Nature-Based Solutions: A Guide for Local Officials" by FEMA:
The Quabbin and Wachusett Reservoirs serve 2.5 million people in central Massachusetts and the Boston area. Over 20 years, the Massachusetts Water Resources Authority spent $130 million on nature-based solutions. The nature-based solutions protect 22,000 acres of the watershed that drains into these reservoirs. A water filtration plant would have cost $250 million to build and $4 million annually to operate and maintain.