Alewife Study Group > other Alewife events > Jan.31 2000, bacteria report Search 

A Snapshot of the Alewife Watershed:
observations and bacterial sampling results from Fall, 1999

Prepared for the Mystic River Watershed Association, January 31, 2000 by Roger Frymire

Full report includes Arlington, Belmont, Somerville, and flooding
As of December 2004 it appears this report is no longer online at - the Mystic River Watershed website is now

Please read sampling scope/procedure and caveats near the bottom of this page.


The 86" Blanchard St. outfall to Wellington Brook also drains significant sections of Belmont. Dry weather tests showed 1,200 cfu/100ml; but 85,000 cfu/100ml in rain. This outfall is immediately adjacent to Belmont outfall #8. This section of Wellington Brook flows into Blair Pond where a huge sandbar has been deposited.

The 36" Normandy Terrace outfall to Wellington Brook north of the R/R tracks tested 1,000 cfu/100ml in dry weather and 11,000 cfu/100ml in rain. However, this pipe was observed flowing in reverse during one rainfall, so these numbers may simply be those of Wellington Brook in this stretch. This conduit was originally built to conduct water from Spy Pond to Fresh Pond. This section still extends under Concord Avenue to the Black's Nook area of Fresh Pond Reservation. It is meant to conduct storm water or overflow from Black's Nook to Wellington Brook. The inverse flow seen could easily be explained by a cross connection to three MWRA sewer mains it crosses just south of the tracks. If that is the case, this inflow could be adding to overflows at CSOs in Cambridge and Somerville. In any case, all flows to Wellington Brook need to be clean in case floods ever send a backup through this pipe to the drinking water at Fresh Pond.

Perch Pond was tested at it's outflow during one rain event at 21,000 cfu/100ml. This was higher than expected and may be due to sediment picked up by storm currents in this very shallow pond, or from a slug of sewage from an upstream source which just happened to pass by at the time.

The marsh west of AD Little corp. drains south through a culvert to more marsh and then the Little River. Wet weather flow at the river tested at 3,600 cfu/100ml. This is higher than expected from a sediment-trapping marsh and could be explained by the possibility that higher river levels could have first stored dirtier flows in the marsh which later flowed out somewhat cleaner. Alternately, Arlington drain #001 could be a partial source of this flow.

The ~30" pipe fronting AD Little corp. tested at 120 cfu/100ml during dry weather one hour after it was seen not flowing.

The beginning of the aboveground portion of Alewife Brook, labeled as CSOs #004 and #401 had an appearance and smell of wastewater, but tested at <10 cfu/100ml during dry weather flow. A wet-weather sample taken downstream of a construction site dewatering discharge registered 4,000 cfu/100ml.

Parkway Pond east of Rt. 2 tested at <10 cfu/100ml during dry weather.

Yates Pond north of the Alewife T station tested at 20 cfu/100ml in dry weather and 570 cfu/100ml in wet weather. This pond is both filled and emptied through a connection to the shallow ditch between Alewife Brook and the following MBTA outfall.

MBTA 48" outfall tested at 760 cfu/100ml during wet weather and had a substantial amount of oil apparently coming from the MBTA garage or station sumps.

Alewife Brook under Rt. 2 tested at 3,900 cfu/100ml during wet weather.

MDC outfall #16(6), over 100 yards upstream of Mass Ave. tested at 1,100 cfu/100ml during wet weather. A significant slick of oil was also traced to this outfall. This is 12" concrete adjacent to a spot on Alewife Parkway where a metal guardrail ends by sloping into the ground. It is in line with a parkway catch basin and also inline with one of the Cambridge streets pointing directly at a WR Grace corp. building.

At a signalized pedestrian crossing of Alewife Parkway is a 15" concrete outfall with a huge rim on the pipe. Wet weather flow was 540 cfu/100ml. I am unclear on whether this is MDC outfall #13(6) or #14(6), listed at 12" and 18"; or possibly CSO #400, listed at 30". None match with my 15" taped measure, possibly due to the rim.

In summary, 15 samples were tested in Cambridge. The two Wellington Brook outfalls as well as a marsh outflow, CSO #004/401 and MDC road drain #16(6) tested over the state boating limit of 1,000 cfu/100ml. In addition, MDC road drain #16(6) and an MBTA garage drain were seen to a significant amounts of oil during wet weather.

Preface and Acknowledgments

In November and December of 1999, I sampled every source pipe evident along Alewife Brook, Little River, Wellington Brook, and Little Pond in the cities of Arlington, Belmont, Cambridge, and Somerville. The samples were analyzed for fecal coliform (a sewage indicator) in the Charles River Watershed Association laboratory headed by Jim Fitzgerald. Testing was funded through the Mystic River Watershed Association. I thank the many employees in these four cities who assisted by helping with documentation and discussion of my observations. All maps are based on historic 1946 USGS topographic maps available online from the University of New Hampshire Library through  


The four cities just got through reporting via the "308" process to the EPA about their stormwater systems, so I will use the same identifiers for outfalls wherever possible. I will group all samples in one city together in a separate section then cover wider issues in separate sections.

The Study Area and Overall Findings

map of study area, with locations of samples and pipes

dot for sample location Location of samples testing over the state boating limit of 1,000 cfu/100 ml for fecal coliform bacteria
symbol for pipe location Pipes seen contributing significant slicks of oil to the waterways

6 - Sampling Scope and Procedures

Mystic River Watershed Association volunteer sampling of Alewife Brook and tributaries excluding Spy Pond - November 1999

SCOPE - One hundred samples will be tested for Fecal Coliform from sources along the banks of Alewife Brook and the Little River. Also included are Blair Pond, Little Pond, and Wellington Brook. Every dry-weather source pipe will be sampled, and most wet weather sources as well. If sample numbers allow, a single set covering the main stem flow during wet weather will be conducted. An estimated 35 dry-weather and 65 wet-weather samples will result. [[Only 66 samples were taken before ice set in. Six wet weather samples would be needed to finish. The main stem series was abandoned as unlikely to useful data.]]

OBJECTIVE - A snapshot of current conditions should result, allowing comparison with recent 308-letter responses, as well as a baseline for noting future improvements in stormwater and sewage. Results will be shared with affected cities as well as EPA and DEP.

PROTOCOL - Standard chain-of-custody forms will document all samples. Sterile containers and sampling methods are employed, with immediate storage on ice. Delivery to the lab is within 2-4 hours of earliest sample time. Though this lab is not certified, I have had excellent replicability here in the past. At the very least, results should be considered highly indicative and used to highlight areas for more official study. [[Certification efforts are underway.]]

PARAMETERS - Dry weather follows at least 72 straight hours of zero measurable precipitation. Wet weather avoids the first-flush phenomenon by waiting until after an hour of minimum 0.1 inch/hour intensity. Acceptably wet weather continues from then for a number of hours equal to the total storm accumulation in tenths of an inch. The ideal is testing during rainfall events of at least 0.1 inch/hour intensity. [[One wet weather set of samples did not fully meet the intensity standard, but the data are still considered indicative.]]

OTHER - Most samples are taken from a kayak in the water. Samples are taken on the initial upstream leg of a paddle trip to avoid contamination or sediment stirring by the sampler. Earlier work on the Charles basin used smell as the prime sampling site indicator. This is impossible on the Alewife, as the entire area scoped stinks intensely of sewerage. Similarly, plumes are useless downstream of the T station since CAM004 and 401 make the water opaque downstream of the Alewife/Little River junction. Luckily most pipes are at or above water level.

7 - Caveat

All opinions and errors in the above report are strictly mine. Maps shown are based on 1946 USGS quadrangles so some streets are missing. Pipe identification from a floating platform is especially hard, but observations coupled with every outfall and drainage map I could locate should ensure that any pipe misidentified is only wrong by one position in an actual accounting. I plan to use a MassGIS DGPS unit to precisely locate each of the outfalls I've listed. This should allow a final correlation as cities computerize their mapping data.

This study is NOT copyrighted. Electronic distribution and unlimited hard copies are explicitly permitted.  

If I can be of assistance in answering specific questions or by giving short presentations on this study, feel free to call or write:

Roger Frymire
22 Fairmont Avenue
Cambridge 02139-4423

(Information from the Mystic River Watershed Association website, - the association is not affiliated with the Alewife Study Group)

Contact the Alewife Study Group, North Cambridge Massachusetts, by email at