The Boston Globe How a tiny Massachusetts river has become a star in the fly-fishing world Cold water, big fish, bigger crowds. Fly fishermen Walter Sysunwater (right) and Thomas Schubert took to ...

Their goal is to stock brook, brown, rainbow, and tiger trout in 264 Massachusetts cities and towns. Stocking will begin the second week of March in the southeast.

The largest in the state, the behemoth structure opened in 1939 and eventually backed up the original three branches of the Swift River, flooding four towns off the map forever.

The Charles River, for example, has 10 different CSOs that flow into it. WBUR has built a tracker map that constantly updates based on real-time alerts for more than 180 CSOs across the state.