Maple Meadow Brook is part of the headwaters of the Ipswich River. Headwaters are where rivers begin so whatever happens here affects the entire system. Water withdrawals and large amounts of paved surfaces all characterize this heavily developed area. Last week, Martha Stevenson and Suzanne Sullivan of the Headwaters Stream Team in Wilmington reported brownish colored, turbid or cloudy water in Maple Meadow Brook in Wilmington. This was observed where the brook crosses Rt. 129 and Rt. 38 in Wilmington. The situation was reported to Mass DEP who quickly followed up by measuring samples for indicators of wastewater discharge; bacteria, ammonia and surfactants (detergents). These results came back negative so I went out in the field with Martha Stevenson to see if we could pinpoint the cause. We suspected the cause was related to nearby commercial facilities or recent sediment disturbance by construction work in the area.
We first investigated the crossing at Rt. 129 next to the Textron facility. The suspended sediment was very apparent, but it was much cloudier at the next upstream crossing on Rt. 38. Neither of these crossings belongs to our monthly RiverWatch monitoring sites so we measured conductivity and dissolved oxygen as a starting point. Conductivity is an indicator of the amount of salts from runoff, sediments or materials found in wastewater that increase the ability of water to conduct an electrical current. This measurement is considered a good indicator of human influence on streams. The level for healthy fisheries is considered to be 150-500 microsiemens/cm, higher than this is a sign of impairment. We recorded a reading of 660! Other readings at our normal monitoring sites in this area have been around 500 to as high as 610 in the spring, most likely the result of road salts. Dissolved oxygen levels were acceptable at 7.5 parts/million with the healthy minimum standard set at 5 ppm. We suspected the high conductivity reading was probably the result of the suspended sediments.
We found similar conditions at the crossing on Rt. 38, further upstream. Conductivity was slightly better at 560, but still elevated. Dissolved oxygen was lower at 5.5, still considered acceptable. Since the amount of turbidity was more apparent at this location we knew we were getting closer to the source. We continued upstream where our attention was drawn to a new culvert recently installed under the railroad tracks. Suspended sediment was visible on the downstream side, but not on the upstream side where water enters from a wetland. We believe the culvert installation was the likely cause of the sediment. We concluded that since there has been so little rain and low flow the sediment had not been cleared by the stream. There were silt barriers still in place; however, we were not able to judge how effective they had been. Sediment is harmful to streams since it can hurt aquatic plants and fill in habitat for fish and other aquatic organisms.
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Protecting the headwaters is important to protecting the Ipswich River, so people in this region can make a significant difference by minimizing impacts on streams and wetlands in this critical region. Ways you can help include volunteering to monitor the watershed as a RiverWatch volunteer or become active with a Steam Team in your area. Stream Teams are made up of members of a community who take on local river protection projects unique to a region such as the headwaters. Please visit our Support page to learn more about volunteering with a Stream Team and other ways you can help.
