Embayment Monitoring to Support Nutrient Management Activities in Connecticut for Long Island Sound

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By New England Water Science Center September 27, 2021

The USGS, in cooperation with the Connecticut Department of Energy and Environmental Protection will be collecting water-quality and hydrologic data at four embayments from April 2021 to March 2025: Mystic, Norwalk, Saugatuck, Sasco-Southport complex, and Farm.

Continuous water quality station on the Mystic River at the Mystic Seaport, Mystic CT — Continuous water quality station on the Mystic River at the Mystic Seaport, Mystic Connecticut (Site ID 412141071580200). Setup includes top and bottom multiparameter sondes and velocity uplooker.

The State of Connecticut continues to promote a comprehensive approach to managing the effects of nutrients on Long Island Sound and its coastal embayments. The USGS, in cooperation with the Connecticut Department of Energy and Environmental Protection, will be collecting water-quality and hydrologic data at five embayments across Long Island Sound: Mystic, Norwalk, Saugatuck, Sasco-Southport complex, and Farm. Data will be collected in these embayments for 2 years. Data collection began in the Mystic and Norwalk in May 2021 and ended April 2023. Data collection began in the Saugatuck and Sasco/Southport Harbor starting in May 2022 and will end April 2024. Data collection began in the Farm in April 2023 and will end March 2025. Discrete water-quality samples are collected at near surface and near bottom at multiple locations at various tidal cycles in each embayment. Discrete samples will be analyzed for nutrients, carbon, total suspended solids, silica, alkalinity, biological oxygen demand, and chlorophyll a. Selected sites will also have continuous water-quality monitoring at near surface and near bottom for water temperature, specific conductance, salinity, dissolved oxygen, turbidity, and chlorophyll a. USGS will also collect hydrologic data, such as velocity and stage, at selected locations in each embayment.

The objectives of the project are to (1) Obtain representative water‐quality data under a range of seasonal conditions to characterize the water quality spatially and vertically within each embayment. (2) Collect selected water‐quality data with high temporal resolution to provide time‐series data needed for water quality model calibration and evaluation. (3) Collect selected physical water‐quality data and velocity data at multiple locations in each embayment to provide spatial data needed for water quality model calibration and evaluation. Nutrient models for each embayment will be created based on the collected data which will help improve the understanding of physical and chemical processes of embayments in Long Island Sound.

Map of Norwalk Embayment Monitoring Sites — Locations of Norwalk embayment monitoring sites in Connecticut.

Map of Mystic Embayment Monitoring Sites — Locations of Mystic embayment monitoring sites in Connecticut.

Map of Saugatuck embayment monitoring sites — Locations of Saugatuck embayment monitoring sites in Connecticut.

Map of Southport embayment monitoring sites — Locations of Southport embayment monitoring sites in Connecticut.

Locations of Farm River embayment monitoring sites in Connecticut.

Data collection sites

Site Number	Site Name
411940071590300*	Mystic River at Ram Island Yacht Club at Noank, CT
412141071580200*	Mystic River at Mystic Seaport near Mystic, CT
412240071574700	Mystic River US Rt I95 bridge near Old Mystic, CT
412047071580800	Mystic Harbor at Safe Harbor Marina near Mystic, CT
412117071580800*	Mystic River at Rt. 1 bridge, CT
410502073236000*	Norwalk Harbor at the Cove Marina near E Norwalk, CT
410606073245700*	Norwalk River at Norwalk Aquarium near S Norwalk, CT
410643073243700	Norwalk River at Ferry Point, CT
410729073171701*	Mill River at Southport Harbor near Southport, CT (Buoy)
410757073165601	Mill River at Pequot Yacht Club at Southport, CT
410613073215801*	Saugatuck River Lower Embayment near Saugatuck, CT (Buoy)
410724073221001	Saugatuck River US Route 136 near Saugatuck, CT
411513072512301*	Farm River at Farm River Marina NR East Haven, CT
411532072510801*	Farm River at Route 142 Bridge Near East Haven, CT
411626072514501*	Farm River at the Trolly Museum at East Haven, CT