An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

Charles River

History of Human Impacts on Charles River

Charles River Timeline
Date Human Activity Impact on the River
4000 BC to 1617 AD Native Americans inhabit watershed Only known impact is remains of fishing weirs discovered in Back Bay
1625 John Blaxton becomes first settler in Boston, building his home near freshwater spring on western flank of Beacon Hill  
1630 John Winthrop and Massachusetts Bay Colony joins Blaxton; additional springs used for water supply  
1634 Grist mill dam erected at Watertown, first of 43 industrial mills to be built on lower Charles Dam changes flow of river, captures sediments, limits fish migration
1643 Dam and mill constructed on current Causeway St. Mill ponds become repositories of industrial waste; 1656 ordinance allows dumping of "beast entralls and garbidg" at North St. without fine
late 1700s Boston streets are paved with cobblestones; underground drainage system for gray water created Paving eliminates recharge of aquifer; springs dry up and become contaminated by privies; private water company brings water into Boston from Jamaica Pond; in 1840 Boston constructs enlarged water supply at lake Cochituate in Natick
1790-present Paving of street surfaces and creation of other impervious surfaces continues; turns an "absorbent" land surface into a "waterproof" land surface; for example, some residential areas of Cambridge are 73% impervious Runoff carries away contaminants such as bacteria, phosphorus lead and Polychlorinated Biphenyls (PCBs) degrading river uses, poisoning fish and increasing algal growth; increases flooding; lowers water table in Boston; creating host of problems. Even today, buildings on pilings at risk due to dry rot; see Globe story of Feb. 2004
1799 First filling of marshes occurs by lopping of the top of Trimountain (now Tremont St.) to make Charles St. Filling eliminates natural estuarine habitat, limits water available for assimilating wastes
1840 Introduction of public water supply spurs development of internal plumbing for waste; waste is conveyed directly to Charles through pre-existing street drains and through newly constructed common sewers carrying storm and sewer water Bacteria load to river increases dramatically; waste on exposed mudflats causes stench thought to spread disease (before germ theory of disease, illnesses thought to be spread by odors or "miasma")
1855-1880s 738 acres of tidal marsh in Back Bay is filled with material from Boston drumlins and then Needham quarries Goal was to eliminate stench from poorly flushed tidal flats: results in reduced estuarine environment, limits assimilative capacity of basin
1878 Construction of first metropolitan sewer creates additional concern over lowered groundwater table; network of groundwater observation wells initiated Goal was to eliminate stench from poorly flushed tidal flats: results in reduced estuarine environment, limited assimilative capacity of basin.
1879 Boston adopts Olmsted's "Sanitary Improvement" of Back Bay; Fens is created by filling 90% of 190 acre section of Back west of Gavelly point. Stony Brook wet weather flow designed to overflow into fens, an artificial marsh with tide gate to keep water elevated; Muddy River diverted to culvert under Brookline Ave to Charles Riverine habitat of Muddy lost. Combined sewer overflows (CSO) discharge into fens remains today; constriction of flow causes flooding in lower Muddy, a problem being ameliorated by $100 million Muddy River Restoration project currently underway
1884 All of Back Bay other than portion at entrance of Stony Brook and Muddy River filled. Reduced river area in combination with sewage load from drains raises public health concerns Sewer interceptors parallel to shore line conveying waste to Moon Island constructed to address sewage discharge to tidal flats and waters; interceptors designed to overspill into surface waters in large storms, creating "combined sewer overflows"
late 19th, early 20th century Stony Brook, largest tributary to Charles is culverted; many of the other major Charles tributaries, including Faneuil Brook, Village Brook, Tannery Brook and parts of Laundry Brook, are also culverted over time Culverted means that the flow of open streams was placed in underground pipes (culverts) and covered over.
1903 Increasing CSO flows into basin along with growing population leads to creation of committee to examine sewage problem; committee decides upon creation of freshwater basin to flood the flats See Dam Construction below
1908 Dam constructed between Boston and East Cambridge at the locus of the current Museum of Science. This dam is replaced by New Dam at Boston harbor in 1978. Intended to alleviate sewage threat by covering tidal flats, dam eliminated estuarine environment in total and created a settling basin for suspended sediments in water: results in heavily contaminated bottom sediment; anoxic zone created by salt water intrusion from harbor; also eliminates tidal flushing in river and makes the "fens solution" unworkable as a result
1965 Charles River Watershed Association founded  
1978 Dam constructed at mouth of harbor to control flooding and enhance fish passage  
1988 As a result of the EPA/CLF (Conservation Law Foundation) Boston Harbor Cleanup Lawsuit, Massachusetts Water Resources Authority (MWRA) creates its combined sewer overflow (CSO) program. Lower Charles had 19 CSOs discharging 1.7 billion gallons per year into lower Charles, 150 million gallons per year (MGY) untreated
1995 EPA issues orders to municipalities to eliminate illicit discharges in city storm drains.  
1995 Clean Charles Initiative launched, with many partners including, the Charles River Watershed Association, Charles River municipalities, and Massachusetts state agencies. Report card issued: grade D  
1997 MWRA's Long Term CSO Plan Approved Plan requires closure of 7 CSOs and reduction of discharges to 162 mgy, 2.3 mgy untreated
2000 Deer Island Plant and outfall tunnel complete

Charles River Conservancy founded
Greatly expanded capacity and secondary treatment at Deer Island reduces CSO flows to Charles and improves water quality in Boston Harbor.
2005 Most known illicit discharges have been removed resulting in well over 1 Million Gallons per Day (MGD) of sewage removed from storm drains. Massachusetts Water Resources Authority (MWRA) has completed most of its 1997 combined sewer overflow (CSO) control plan.

Charles River Swimming Club founded.
Under orders issued in the fall of 2004, Waltham, Watertown, Newton and Brookline required to eliminate illicit discharges. Work continues on illicit discharges by Boston Water & Sewer Commission by 2012 consent decree. CSO flows in lower Charles have been reduced by 90%.
2005 Report card issued: B+  
2006 Separation of Stony Brook completed Stony Brook is the largest remaining source of bacteria to the lower Charles
2007 EPA and Massachusetts Department of Environmental Protection (MassDEP) establish Total Maximum Daily Load (TMDL) for lower Charles River to reduce levels of phosphorus  
2008 Municipalities with known problems are currently under orders to find and eliminate problems through comprehensive, top-down investigation.  
2012 EPA, Department of Justice (DOJ), and Conservation Law Foundation sign Consent Decree (CD) in U.S. District Court – CD requires Boston Water and Sewer Commission (BWSC) to identify and remove illicit connections to the storm drain system on a schedule  
2013 MWRA and Town of Brookline complete $26.7M Brookline sewer separation project – Project will lower CSO discharges to the Charles River  
2014 20th anniversary year report card grade: B+