CRAB and MIT Sea Grant Chart of the Charles River

We have made great progress toward establishing a depth chart of the Charles River between the New Charles River Dam and the Watertown Dam. Except for a few small areas, we've measured the depth from the New Charles River Dam to Hyde Brook west of Newton Yacht Club. With field measurements finished for this year, hard-copy and on-line versions of these depth charts will be released to the public soon. We need your help to allow us to finish the field measurements next summer and to further refine the charts. Any excess funds will be set aside for future work to characterize changes in the river.
If you use the river, please make a contribution to the project by sending a check to
Dave Amicangioli, CRAB Treasurer
25 C Street
Belmont, MA 02478


As can be seen in the graphic above, we have measured data along much of the river. However, at this point in time, we have publicly released data for the area between the BU Bridge and the New Charles River Dam. We are still reviewing data upriver of the BU Bridge to ensure accuracy. We anticipate releasing the full chart, in several different formats, later this winter.

The Charles River in Massachusetts is an urban river that is also one of the most active recreational rivers in the country. Unfortunately, sediment deposition has been a long standing problem in the Charles River. It was recently highlighted in articles published by the Boston Globe in 2011 and WGBH in 2016. In recent years, sediment deposits have caused several incidents that have resulted in damage to watercraft and personal injury. While the sediment appears to be a larger problem where major tributaries - Laundry Brook, Hyde Brook, Faneuil Brook, Muddy River, Stony Brook - empty into the Charles, once the sediment is in the river, it can spread to other areas, causing further problems especially where it is already shallow. This problem is not limited to the areas upstream of the BU Bridge. A significant bar upriver of the Massachusetts Avenue Bridge is shallow enough and large enough to be a navigation hazard to both sailboats and motorboats. There are also the extraordinary events such as the water main breaks in Weston in May 2010 and near the Anderson Bridge in August 2015, both of which caused large amounts of sediment to be moved.

It has been difficult to marshal the resources to remediate areas impacted by sedimentation since much of the knowledge about the shallows and bars has been anecdotal, coming from the daily experiences of the boaters on the river but not backed up by quantitative data. To address this issue, the Charles River Alliance of Boaters (CRAB) has developed a partnership with the MIT Sea Grant College Program to create a chart of the river depth between Science Park and the Watertown Dam, and to monitor changes in the river bottom in the future. Based upon some feasibility studies done in late 2015, more detailed and extensive measurements were undertaken in 2016. To date, most of the river between the New Charles River Dam and Hyde Brook west of the Newton Yacht Club has been surveyed. We plan to complete measuring the few remaining sections once the plant growth there has died back with the colder weather that autumn brings.

The initial scope of the project is described below:

  1. Depth Measurements:
    Inexpensive fish-finders were used to record the depth, as well as the time and GPS position of each sonar reading. While the depth is measured by the delay in the sonar echo, the relative hardness of the river bottom can be inferred from the strength of the sonar echo. The project team used a Lowrance HDS-7 chartplotter/fishfinder with Point-1 GPS, HST-WSBL broadband, and LSS-2 sidescan sonar transducers for depth measurements. In areas of the river that are wide, survey lines were spaced between 30 and 65 feet apart and driven at speeds generally between 3 and 4.8 knots. Where the river is narrow, several passes were made up and down the river over multiple weeks. Broadband sonar was used during the entire survey, resulting in recordings of both depth and relative hardness of the river bottom, as well as time and position of each sonar reading. In addition, sidescan sonar was used downriver of the BU Bridge to capture images of the river bottom and objects of interest.

  2. Influence of Daily Water Releases:
    As part of flood control measures, water from the river is released into Boston Harbor at low tide and held in the river at high tide, slowly accumulating. This causes the water level in the river to change over several inches during the course of a day. A gauge at the First Street Bridge in Cambridge records the variation in the height of the watersheet. While this gauge is a good measure of the watersheet downstream of the BU Bridge, there are no gauges further upriver and the variation in the height of the watersheet is not well understood.
    In order to better understand the variation in watersheet over the entire survey area, the project team installed Crain 4 ft. stream gauges and Onset HOBO Model #U20L-04 Water Level Data Loggers at Riverside Boat Club, Herter Park, and Community Rowing. These additional gauges provided insight into how the height of the watersheet varies along the length of the river. During the 2016 summer, the gauges indicate that the river acted as a lake, with the height of the watersheet varying uniformly along its gauged length within 0.1 ft. If there had been more rainfall or more substantial dam releases, it was expected that the height of the watersheet would have varied along the length of the river. We plan to keep the additional gauges installed for a few years and to monitor how the height of the watersheet changes during periods of significant rainfall.
    In order to more accurately determine the depth of the river, all raw depth measurements have been adjusted to account for the variation in the height of the watersheet, and referenced to a First Street Bridge gauge height of 107.5 ft. Datum of gauges are from the Massachusetts Metropolitan District Commission base, which is 105.62 ft higher than NGVD 1929.

  3. Development of Digital Charts:
    The raw sonar data gathered in the field was first processed using ReefMaster PRO mapping software. This generated two-dimensional contours of both depth and relative hardness that were then exported as ESRI shapefiles. ReefMaster was also used to construct sidescan sonar mosaics of the river bottom. ArcGIS ArcMap was used to organize additional geospatial data, including landmarks, elevated structures, detailed shorelines, and contour annotation into completed charts. The web version of the chart is the product of a simplified workflow combining the best of ArcGIS and open-source web mapping frameworks. The refined, multi-layer map package developed in ArcMap is uploaded to ArcGIS Online, where the individual layers are made available as Web Map Services (WMSs). WMSs is then used to import the ArcGIS Online layers into a mobile-friendly, highly-customizable web environment coded in Leaflet and CartoDB javascript frameworks.

    To enable the public to access this data, the following formats have been developed:
    • Chart Booklet: A printable PDF file that includes an overview of the river from Watertown to Boston Harbor, and more detailed charts of each section of the river.
    • Large Format Overview: Intended as a 24"x36" print, it presents a view of the entire river from Watertown to the Charles River Dam, showing river bottom depths and contours. This format is suitable to be displayed on the wall of every boathouse.
    • Google Map and Google Earth: On-line versions of the depth data using both Google Maps and Google Earth.
    • Online GIS: Additional representations of the river data using ArcGIS are available on the MIT Sea Grant project website.

These charts are intended to be used as an aid to recreational boaters, but should not be relied upon for navigational purposes because of the limitations on scale and ever-shifting depths of the river. The use of these charts are at the user’s sole risk. The user agrees that neither CRAB nor MIT shall be responsible for any injuries or property damage that a user or others suffer or cause from the use of these charts or any Data related to the Project. The user shall indemnify and hold CRAB and MIT harmless from any claims arising from its use.
Copyright © 2016 Massachusetts Institute of Technology. All Rights Reserved.

Financial Support:

To complete this project and ensure operation in future years, to develop comparative data over time, we need funds to obtain the equipment and to support the personnel working on the project. If you would like to financially support this project please send your checques to:
      Dave Amicangioli
      CRAB Treasurer
      25 C Street
      Belmont, MA 02478
Thanks in advance for your support!!!

Depth Charts

Limited Public Release
New Charles River Dam to BU Bridge only
Full Release expected soon

Useful Information

Press Coverage

Help Support the Project...

For those interested in financially supporting this project, please send your checques to:
      Dave Amicangioli
      CRAB Treasurer
      25 C Street
      Belmont, MA 02478
Thanks in advance for your support!!!

We would like to thank the following donors that provided the initial funding to get the project started:

MIT Sea Grant
Boston Duck Tours
Head of the Charles Regatta
Newton Yacht Club
Riverside Boat Club
Union Boat Club
Community Boating