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Summary of Health Hazards in Cambridge and Belmont
Winter 2003, Little River - Alewife Brook subwatershed
Mark Kirk of FAR with information from the water quality testing team of the Mystic River Watershed Association.
Mystic River Monitoring Network - Libby Larson: Coordinator

 

Alewife Brook

 

Testing Sites:

For baseline monitoring, samples are collected the second Wednesday of each month from the Somerville side of the Brook, just downstream of the Broadway Bridge.  This site is referred to as ALB006.

 

For the samples collected from pipes, the following abbreviations were used:

 

MBTA48

48”Alewife ‘T’ outfall beside Yates Pond

CAMD37

Alewife Brook ‘beginning’ near ‘T’ marked CSO004

ACORN1

Pond East of Acorn Park Drive’s West end

HWY001

Mass Highway drain by concrete post to ditch between Oliver Rd, Lake St

CAMD38

Huge round pipe on South end of open segment by Fawcett St.

CAMD36

Fawcett St rectangular drain to West side of open segment

CAMD34

Little Pond Conduit to Wellington Brook North of R/R tracks

CAMD33

Blanchard St drain (rectangle) at Wellington Brook

BEL08S

Center (round) outfall to Wellington Brook at Brighton/Blanchard

BEL08N

Northernmost (outside round) Wellington Brook @ Brighton/Blanchard

BEL01x

Brighton St drain to Little Pond between Pond St and Sandrick Rd.

WEB013

Wellington Brook @ Common Street

WEB007

Wellington Brook outfall to Claypit Pond

WIB001

Winn's Brook outfall to Little Pond

SOMD11

CSO SOM004 by pump station

MDC86

36" MDC #8(6) by Fairfax Street

SOMD10

12"clay aka MDC #6(6)

SOMX01

Clay pipe in square bulkhead

ARL027

Pipe with flap on end

SOMD09

CSO SOM002A/SOM003

SOMD08

CSO SOM002

ARL026

In front of gate in fence

MDCX01

MDC 'lost' drain in undercut in bank

SOMD07

Storm drain just downstream of Broadway

ARL017

Broadway main drain

ARLX02

Smaller Broadway drain under bridge near upstream end

SOMD05

2nd pipe downstream of Henderson

ARL014

First drain upstream of Henderson

ARL013

2nd drain upstream of Henderson

ARL011

Mass Avenue Drain in abutment

ALB013

Alewife Brook centerline downstream of Rt 2

ADL001

ADL office park drain

ADL001

ADL office park drain DUP

MARSH1

Outflow from 'Martignetti Marsh'

WEB001

Wellington Brook mouth @ Perch Pond

BEL013

Spy Pond Conduit

BEL011

Drain to NW corner of Little Pond

 

For centerline sampling, the last 3 digits of the site ID indicate the location of the site in river miles from the mouth, e.g. ALB006 is 0.6 miles from the mouth at the Mystic River.

 

Results (Summary):

 

All of the waters tested have been classified as Class B waters, meaning that the water should meet fishable and swimmable standards.  The Massachusetts Surface Water Quality Standards (MASWQS, 314 CMR 4.00) for primary and secondary contact are 200 cfu/100ml and 1,000 cfu/100ml, respectively, of fecal coliform from a single sample.

 

For the June 2002 sampling event, again four out of twenty-seven samples met the MASWQS for swimming, with the same three Little River samples coming up "clean."  None of the samples violated the criteria for boating.  The geometric mean for this event was 296 cfu/100 ml.  Rainfall prior to the event was 0 inches, except 0.07 inches was recorded two days before the event.

 

Pipes monitoring – Most of the pipes sampled in April 2002 were clean, however there are several exceptions to note:  MBTA48, HWY001, WEB013, MDCX01, SOMD07, ARL014, ARL013,  MARSH1, BEL013, BEL011 (with exceptionally high results above 100,000 cfu/100 ml), and WIB001.   There was only trace rainfall in the three days prior to this event.   Repeated sampling of select pipes in June 2002 showed reduced levels at both ARL014 and ARL013, and increased levels at BEL013, BEL011, and WIB001.  BEL011 had results greater than 200,000 cfu/100 ml. 

 

 

Conclusion:

 

It is quite striking that during dry weather, the centerline results for Alewife Brook have consistently across time and space come up relatively "clean," despite some very large inputs from area pipes.  The high inputs into Little Pond clearly settle out so that the Little River water is very clean.  Following the Brook downstream, however, inputs from Wellington Brook again raise the bacteria levels, which then generally decline as the Brook flows to the Mystic, although there is some elevation in the ALB009 - ALB015 range. 

 

The variation seen in the "Alewife Brook Centerline Fecal Coliform Results" could be due to the poor precision of bacteria analysis methods alone (i.e. culturing bacteria from the same sample bottle often yields results that differ widely but are the same order of magnitude).  The results are all in the same order of magnitude and the graph could be considered essentially flat line.  Eliminating these large point sources and improving the flow conditions of the Alewife could potentially lead to the development of a dry-weather TMDL for Alewife well within the limits of the MASWQS for Class B waters.

 

Baseline monitoring at ALB006 revealed that the Brook violates both the primary and secondary standards for Class B waters, especially during rain events.  In October 2002 we completed some wet-weather sampling of select pipes along the Brook, although we have not yet received the results from the Lab.  We hope to do more in the future as weather and resources permit, in order to evaluate the impact of wet weather pipes and non-point sources on the system.


 

Wellington Brook

 

Testing Sites:

 

WEB022

Belmont source for Junction Brook at 170' elevation off Pleasant Street @ McLean.

WEB020

Belmont's Junction Brook by Pleasant Street at 80' elevation.  Just before it goes underground to join Wellington Brook.

WEB013

Belmont where Wellington Brook emerges from under Common Street to run behind the Library.

WEB010

Belmont behind East end of Library where brook goes back underground next to the pool and low area used for skating.

WEB007

Belmont by Concord Avenue where Wellington Brook flows into the SW corner of Claypit pond.

WEB005

Belmont in the NE corner of Claypit Pond by outlet.

WEB003

Belmont where Wellington emerges from beneath Brighton Street before it mixes with Cambridge drain to enter Blair Pond.

WEB002

Cambridge Blair Pond outlet North just before R/R.  This shows both the addition of the Cambridge drain at Blanchard Street, and some settling of contaminants in the pond.

WEB001

Cambridge before Perch Pond (end of Wellington Brook) but after the last stormdrain mixes in from Normandy Terrace and Blacks Nook.

 

Results (summary):

 

All of the waters tested have been classified as Class B waters, meaning that the water  should meet fishable and swimmable standards. For fecal coliform, all but two of the results violated the Massachusetts Surface Water Quality Standards (314 CMR 4.00) for primary and secondary contact.  The two sites which met primary contact standards were Belmont in the NE corner of Claypit Pond (WEB005), and Junction Brook at Pleasant Street (WEB020).  The highest result for fecal coliform (65,000 cfu/100 mL) was at WEB013, Wellington Brook behind the library.

 

Two sampling locations had dissolved oxygen (DO) results below one of the criteria established by the state.  Wellington Brook in Cambridge before Perch Pond (WEB001), and Wellington Brook in Cambridge at Blair Pond (WEB002) both had percent saturation readings below the MASQWS standard of 60%.

 

Conclusion:

 

The high levels of fecal coliform and E. coli bacteria are of concern for public health, especially because many of the sampling locations have easy public access.  The two locations nearest the Library have the easiest and most frequent public use.  However, during these winter months the potential for public contact is reduced.  Due to the very high results at several locations (particularly the location behind the Library), we hypothesize that sewage is contaminating the Brook at points currently culverted.  Additional bracket sampling would be required via manholes to determine precise locations.  The Mystic River Watershed Association would be happy to assist the town of Belmont in any further sampling and investigation.

 


Winn's Brook

 

Testing Sites:

 

WIB001

Winn's Brook outfall to Little Pond

WIB003

Grate over Brook East side of Waterhouse Road

WIB005

Grate over Brook North side of Sherman Street

WIBUTA

Grate over Tributary 'A' @ 32 Frost Street

WIB009

Brook beside 73 Claflin Street upstream of grate

WIB012

Brook East side of Clifton Street by Hickory Lane

WIB013

Brook at Howells Road footpath bridge

WIBUTB

Tributary 'B' South side of Pleasant West of Clifton St

ATB004

Atkins Brook by wetland pond in Audubon Sanctuary

 

Results

 

For the baseline monitoring, the geometric mean for WIB001 is 844 cfu/100 ml for the period 7/2000 – 5/2002.  For these samples, 75% violated the standard for primary contact, and 46% violated the standard for secondary contact.

 

For the March 26th monitoring, 4 samples violated the primary contact standard, and only 2 violated the secondary contact standard.  The two violations occurred at WIB001 and WIB005 (Grate over Brook North side of Sherman Street). 

 

One sampling location had dissolved oxygen (DO) results below one of the criteria established by the state.  Atkin's Brook had a percent saturation of 58.3%, just below the state standard of 60%.  This is probably due to the effect of the nearby wetland on the Brook.

 

While there are no state standards for salinity, salinity can be an indicator of probable contamination.  For the March 26th sampling, salinity ranged from 0.2 ppt at Tributary A (WIBUTA) to 0.6 ppt at Tributary B (WIBUTB) and WIB003. 

 

Conclusion

 

The high levels of fecal coliform and E. coli bacteria are of concern for public health, especially because Winn's Brook discharges into Little Pond, which is used recreationally.  Atkins Brook and upstream sections of Winn's Brook are very clean.  Due to the higher concentrations of fecal coliform downstream at WIB001 and WIB005, we hypothesize that sewage is contaminating the Brook at points currently culverted.  Additional bracket sampling would be required via manholes to determine precise locations.  The Mystic River Watershed Association would be happy to assist the town of Belmont in any further sampling and investigation.