Belmont Has One Year to Clean up Waterways

By Anne-Marie Lambert

A 2017 consent order from the US Environmental Protection Agency (EPA)  gave Belmont five years to stop underground sewage from leaking into our waterways. We made a lot of progress in 2020, but there could be a long way to go before all our outlets run clean.

In 2020, the town undertook a $550,000 sewer system rehabilitation construction project (SSRCP). More work is planned in 2021 under a sump pump removal and sewer rehabilitation contract. The SSRCP included significant work such as:

• Repairing and lining several sewer mains
• Lining many sewer service laterals
• Removing a few sewer service laterals from the drain system
• Replacing several sewer and drain segments that are beyond repair

Good News

There are some encouraging examples of 2020 rehabilitation work improving water quality at downstream outlets. Up on Belmont Hill by Route 2, for example, outlet 15A by Frontage Road near Radcliffe Road went from over 14,900 E. coli MPN/100 ml in 2017 to under 100 MPN after a 2020 project to reline and repair mains under Knox, Herman, and Bellington Streets. The EPA threshold is 235 E. coli MPN/100 ml.

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MPN Measurements

The concentration of E. coli bacteria in water is measured in terms of MPN per 100 ml. MPN stands for “most probable number.” Several samples of the liquid are cultured and checked for signs of E. coli growth. The pattern of growth across samples is used to estimate the concentration of bacteria in the water source.

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In other areas of town, water quality improved after significant rehabilitation, but still not enough to meet EPA requirements. Work in the Oliver Road neighborhood should address water quality issues at outlets 11, 11A, and 12. In other areas, there is no more construction or investigative work planned. The hope is that after recent repair work, the system will eventually run clean.

Rehabilitation work is planned on Hoitt and Westlund Roads in the lower part of catchment 10. More investigation is planned in 2021 to discover additional upstream sources of sewage infiltration. Techniques may include sending CCTV cameras down the drains, going door-to-door, and doing dye testing to find illegal connections of sewers to the drain system.

		Pollution Measurement (E. coli MPN/100 ml)
Sub-catchment	Location	Before (2017)	After (2020)
11	Oliver Road	13,800	1,200
11A	Oliver Road	>20,000	2,600
12	Oliver Road	1,600	200
11,11A,12	Upstream Project 6 (planned): Oliver Road Point of Service Replacement, lateral liners
15	Park Rd @ Grove St North	10,200	700
8-6	Outlet 8-6: Pearson and Gordon Terrace	14,400	1,300
8-6-6	Creeley @ Leslie from easement	>20,000	5,000
8-6-22	Trapelo from TD Bank pipe	N/A	4,300
8-6	Upstream Project 5: Relining of mains and laterals on Maple, Bartlett, Trapelo

Table 1. Some areas showed significant improvement, but are still above EPA’s E. coli threshold

Measuring Pollution, Managing Odds

The town’s consultants usually take samples from our drains and outlets in the early morning and also measure levels of E. coli during wet weather. The reason for this timing is that a single good measurement at a downstream outlet is not necessarily a reliable indicator that all is well upstream. Sewage enters the drain system sporadically, with each flush or laundry load, so any given measurement may miss E. coli leaking into the drain system. Standard practice is to take measurements in the early morning as residents are waking up so that there is a better chance of detecting waste leaking into the drain system.

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Human or Animal Waste?

How does the EPA tell if the E. coli is from animal or human waste? In 2017, the EPA included measurements of pharmaceuticals unique to humans to verify the E. coli were coming from human waste and not from dogs, geese, or other animals.

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Another reason for making several measurements is that the E. coli bacteria being measured in the drain or waterways decay over time. E. coli can survive on dry surfaces for about a day, in still or culverted water for up to two months or more, and in the soil for up to three months (or longer if it becomes established in the soil). Survival rates vary based on temperature, availability of nutrients, pH, and solar radiation. Depending on the weather conditions, a single measurement at an outlet may not detect a problem far enough upstream for E. coli to have decayed or dissipated into the soil.

All this makes me wonder how valuable the town’s sporadic measurements of the Winn Brook outlet are. Luckily, there is another group measuring this outlet monthly: the Mystic River Watershed Association.

 

		Pollution Measurement (E. coli MPN/100 ml)
Sub-catchment	Project/Location	Before (2017)	After (2020)
1	Outlet at 9 Oxford Circle, near Belmont Street and Mt. Auburn Street	1,900	<100
1-4A	Fairview and Van Ness from easement	7,000	12,300

Table 2. At our border with Cambridge near Belmont Street and Mt. Auburn Street and at the Winn’s Brook outlet into Little Pond, the main outlets seem to be acceptable despite evidence of pollution upstream. Some upstream areas still have disturbingly high levels of E. coli. Source: Town of Belmont Order on Consent Docket No. CWA-AO-R01-FY17-11 Report On Compliance, January 31 2021.

Clearing the Upstream first

In some locations, the town’s 2020 upstream measurements showed improved water quality after major repairs and relining activities, but downstream measurements at the outlet were even worse than in 2017. For example, Catchment Area 2 results show improved water quality measurements upstream after rehabilitation, yet measurements at the downstream outlet for the entire area are worse. The results at the outlet may improve with time, or there may be yet another problem to find and fix.

This is consistent with the town’s “outside-in” approach, which involves fixing problems upstream first, on the periphery of the drainage system. The town plans to wait and see if the outlet measurements improve before investing in significant investigations downstream.

		Pollution Measurement (E. coli MPN/100 ml)
Sub-catchment	Location	Before (2017)	After (2020)
10	Outlet of Winn’s Brook into Little Pond	200	<100
10-2	Upstream project 9 (planned): Disconnect sewer service lateral from drain at Hoitt Road
10-1	Claflin north of Alexander (open culvert)	0	7,900
10-1-1	Clifton and Pleasant	500	2,100
10-1-2	Claflin at Alexander from Claflin	100	10,600
10-1-3	Belmont Hill School Athletic Center	N/A	<100
10-1-4	85 Clifton from East	N/A	2,600
10-1-5	Winn’s Brook at Hickory Lane and Clifton (open culvert)	N/A	1,500

Table 3. Winn’s Brook Catchment area 10: the outlet into Little Pond looks good, but problems persist upstream.

More Work to Do

Table 3 lists a handful of additional projects planned for the 2021 sump pump and sewer rehabilitation contract as well as some sampling and investigation projects.

The goal of all this work is simple: all outlets should have E. coli measurements below the EPA threshold. Estimating how much work remains to get there is very difficult. Because of the intermittent nature of the leakage and the uncertainty of exactly what any given measurement signifies, we have no idea if we are halfway there, 10% of the way, or 90%. Until all the outlets run clear, we won’t know whether we will meet the 2022 target set by the EPA in 2017 of 235 E. coli MPN/100 ml of water. What we do know is that there are still quite a few places well above the EPA threshold.

Despite the pandemic, the town did an impressive amount of sewer rehabilitation work in 2020. The town will need to continue to show the grit and persistence it has pursued in 2020 to find and fix all leaky mains and laterals and illegal connections between the sewer and drain system.

Anne-Marie Lambert is a former director of the Belmont Citizens Forum.