Thanks to the hard work and dedication of the Charles River Alliance of Boaters (CRAB) and the Massachusetts Institute of Technology (MIT), boaters can now see the water depth across the width of the Charles River from the Galen Street Bridge at Watertown Square all the way downstream to the Zakim Bridge, without even touching the river bottom. CRAB and MIT were able to produce this river depth chart, also available in Google Map, Google Earth, booklet, and poster formats, by recording water depth measurements using a Lowrance HDS-7 chartplotter/fishfinder with Point-1 GPS, HST-WSBL broadband, and LSS-2 sidescan sonar transducers.
In addition to providing useful information to boaters trying to navigate the Charles, the results from this mapping effort highlight the physical impacts of urbanization on the Charles River. Scour pools, areas where the river channel has been made deeper because water moves faster through constricted areas, have formed around every bridge from Arsenal Street to the Boston University Bridge. Stream restoration science suggests that the communities around the Charles River should seek opportunities to lengthen these bridge spans and create more natural, vegetated river banks as redevelopment projects are planned in these areas.
Immediately upstream of the Massachusetts Avenue Bridge, the opposite scenario occurs. Where the Muddy River discharges into the Charles, we see deposition of sediment and mud, creating a potentially dangerous shallow area. Both Boston and Brookline are already obligated to help reduce sediment pollution in the Muddy River as part of the Muddy River Restoration Project, but water quality monitoring in the Muddy and Charles Rivers should continue during the implementation of these restoration measures in order to ensure that they are effective.