Author: Stephen Silva

The TRWA sponsored 2018 study of the threatened Diamondback Terrapin  (a brackish water turtle) are on the website under the “Protect and Restore” drop down menu at the top of our home page under “Turtle Conservation” and at this link.  Diamondback Terrapin populations occur along the southern part of the state including populations in Assonet Bay and Broad Cove.  Assonet Bay is a small, tidal inland bay surrounded by the shores of Freetown and Berkley and is part of the Taunton River Watershed.  A small freshwater river flows from Long Pond southwest into the Bay, which then connects with the Taunton River that flows into Mt. Hope Bay.  In 2018 the study area was expanded to include Broad Cove a small, tidal, natural cove located on the border of Dighton and Somerset which is adjacent and west of the Taunton River 

Nesting Diamondback terrapins at both sites have been documented, but no thorough studies have been conducted to estimate the size and structure of this/these population/s.  The objectives of this multi-year study are to estimate the population size, age structure and sex ratio of Diamondback Terrapins in Lower Taunton River through Mark-Recapture.  Results from these studies are critical in the future management and conservation of this threatened species in Assonet Bay as well as other populations in southern Massachusetts.

Fifty-seven unique individuals were captured and just one recaptured individual in the first 3 years of the study.  2018 was the first year that attempts to protect nests took place.  The nesting areas identified in the 2017 report where found to be in continued use in 2018.  Identified nests where covered by wire cloth which was kept on top of the nest by ground staples to prevent depredation along with flagging tape marked with the date each nest was found.

Our nitrate, total phosphorus and fecal coliform results for October are on the Monitoring Program Page of the website.  The October samples give us the information needed to calculate the 2018 averages for the water quality months of May through October that EPA uses in discharge permit limitation averaging (last column in the table).

Despite the fact that the summer of 2018 was hot and river flow usually low just before our sampling days in July (7/10) and August (8/7) there were rain events which temporarily increased river flow and dilution.  Our data reflects this in lower nitrate levels than those measured in July and August of 2016 and 2017 as shown on the website.  Also due to sampling after rain storms we saw higher fecal coliform results in 2018 than in the previous two summers.

Even though we sampled at temporarily high summer dilution events the average level of nitrate measured is 0.56 mg/l well above the MassDEP and EPA based instream healthy estuary target of 0.4 mg/l nitrate that we use.  This illustrates the critical importance of long term data collection or we would not have seen the much higher more typical levels measured in previous years.

Long term we are looking for two things to significantly improve water quality and aquatic life species diversity in the Taunton river watershed.  Completion of the treatment plant upgrades to remove nitrogen due by the summer of 2022 for the Taunton WWTP and the WWTPs plants upstream, and more common use of stormwater best practices to “Soak Up the Rain” (e.g. the new Taunton Riverfront Park rain gardens).

TRWA monitoring is helping us understand how the river is responding to stewardship efforts to improve wastewater treatment (better N and TP removal) and stormwater management; along with the increasingly extreme weather (droughts and floods) associated with climate change and sea level rise.

Our last 2018 sampling day is Tuesday, November 13th.  Anyone interested in joining our volunteer sampling team should contact the TRWA office and plan on attending our next sampler training event scheduled for the last Saturday in February (2/23/2019).

Please join us for the State of the Taunton Watershed Workshop: Building Partnerships for Progress on October 1, 2018, from 8:30 to 1:00 at Fall River Heritage State park.  Click here to see the draft program.

The September nitrate, total phosphorus and fecal coliform results have been added to our 2018 monitoring results summary spreadsheet and the Monitoring Results Page on the website.  We had rain before our sampling event which temporarily increased river flow.  We had the same thing happen before our July and August sampling events as well.  In the low gradient Taunton River (20 feet elevation change in 40 miles of river) summer storms increase river flow for several days until the river drops back to low flow conditions.

Despite the temporarily higher than usual river flow on our September 12th sampling date, nitrate values exceeded the water quality target by 2 to 3 times in the lower watershed and 6 to 8 times in the upper watershed.  Also as a result of the storm fecal coliform results were higher than we typically measure.

Our next sampling event is Tuesday, October 9 (the second Tuesday of the month as usual).

Please consider joining us for the State of the Taunton Watershed Workshop: Building Partnerships for Progress on October 1, 2018, from 8:30 to 1:00 at Fall River Heritage State park.  Click here to see the draft program.

The July nitrate, total phosphorus and fecal coliform bacteria monitoring results have been posted on the website under the Water Quality Monitoring tab at the top of the website home page.  The results continue to show high nitrate levels as in past sampling.  Total phosphorus levels were higher than July of 2016 and 2017.

Our monitoring continues to illustrate the importance of watershed wastewater treatment plants completing required upgrades to remove nutrients (nitrogen and phosphorus) as soon as possible as well as all watershed residents being careful to clean excess fertilizer off driveways or other hard surfaces after fertilizer application.  Another source of nutrients is stormwater runoff.  Measures to “soak up the rain” by letting stormwater runoff from hard surfaces infiltrate into the ground (infiltration Best Management Practices) also reduce instream nutrient levels and increase summer stream base flow resulting in a double environmental benefit.

The June monitoring data is available at the website Water Quality Monitoring Program tab above. River flows were still high as evident from the difficulty our canoe trip participants had making their way under the old Plymouth St. Bridge on the Nemasket River. Water temperatures were generally a couple of degrees warmer than last month.

We again had 100% coverage of all sampling location which is a tribute to the dedication of our volunteers! Despite the high flows mentioned we measured 10 exceedances of our nitrate target of 0.4 mg/l throughout the watershed and 2 exceedances of out total phosphorus target on the lower main stem of the Taunton.

Since our June 12th sampling the Taunton river watershed like all of Massachusetts has been experiencing dry conditions. River flows have begun to decrease and we are starting to see visual evidence of algae blooms. Our July 10 sampling will be important to document further exceedances of the EPA and MassDEP instream water quality targets referenced in the Fact Sheets for the last round of NPDES permit reissuances. TRWA monitoring documents the need for those municipalities that have not finished their plant upgrades to stay on schedule and for EPA and MassDEP to move forward with reissuance with the last two outdated permits in the watershed Somerset and Fall River.

Great weather and participation in this years two day canoe kayak trip made for a fun time for all!

The group started from Oliver Mill Park on Saturday, June 9th traveled down the Nemasket River to the Taunton River and on to historic Camp Titicut in Bridgewater a former Native American campsite. Several families and participants camped overnight.

On Sunday the campers were joined by new arrivals for the second leg of the trip from Camp Titicut in Bridgewater to the Taunton Riverfront Park at the Weirs where the TRWA sponsored Taunton River Festival was underway.

We had sample collection at 100% of sites again this May. Thank you to all the dedicated members of the TRWA Volunteer Monitoring Team!

The results look similar to April and May of 2016 and 2017 (past data on website) beginning to show some marginally high nitrate values on the main stem of the Taunton and lower Three Mile Rivers. Town River in Bridgewater spiked early this year to 0.9 mg/l (over twice our 0.4 mg/l target). In past years the Town River didn’t start to spike to high values until June or July. The Matfield River was high last month but low in May, We don’t know if the Brockton Wastewater Treatment Plant (WWTP) started to experiment with better nitrogen removal in May.

We will continue to watch to see if nitrogen levels spike throughout the watershed from June/July to November as we have seen the past few years once river flow is lower. TRWA is the only one monitoring in the upper Taunton watershed on a regular basis. This monitoring is very important to understanding what is happening in the watershed and documenting the need for better nitrogen removal at WWTPs which dominate summer river flow and better stormwater control to reduce pollution and conserve groundwater for river base flow augmentation.

A piece of good news is despite high rainfall and river flows the fecal coliform levels on the days we tested were low both in April and May. This is good for recreation on the river so please check out our June 9 and 10 canoe/kayak trips on the website or our Facebook page