Research about Herring River

USGS2023

Assessment of prerestoration water quality in the Herring River to support adaptive management at the Cape Cod National Seashore

In 2020 and 2021, the U.S. Geological Survey, Cape Cod National Seashore of the National Park Service, and Friends of Herring River cooperated to assess nutrient and suspended sediment concentrations across the ocean-estuary boundary at a dike on the Herring River on Chequessett Neck Road in Wellfleet, Massachusetts, that has restricted saltwater inputs by regulating water inflow through three culverts or sluiceways into the watershed for more than 100 years. The dike is slated to be removed, and the purpose of this project was to characterize natural variability of nutrient and suspended sediment concentration during flood tide and ebb tide conditions at the dike based on seasonal and environmental variables. This baseline can be used to assess if removal of the dike is likely to result in measurable changes in water quality. Data from the current [2023] study were aggregated with previously published data from November 2015 through September 2018 to provide a long-term record. Samples for the current [2023] study were collected from flood and following ebb tides approximately twice per month from June 2020 through December 2021 at fixed time intervals after the beginning of the tides. Samples were analyzed for nitrate plus nitrite, ammonium, total dissolved nitrogen, total nitrogen, orthophosphate, total dissolved phosphorus, total phosphorus, silica, dissolved organic carbon, and suspended sediment. Constituent concentrations generally were lower using fixed time sampling than in previous studies that used flow-weighted composite sampling, except for nitrate plus nitrite and orthophosphate. Concentrations of nitrate plus nitrite, ammonium, total nitrogen, total dissolved nitrogen, silica, and dissolved organic nitrogen generally were higher on the ebb tide than on the flood tide. By contrast, concentrations of orthophosphate, total phosphorus, and total dissolved phosphorus were generally similar between flood and ebb tides. Most nutrient concentrations except silica and ammonium varied seasonally on flood and ebb tides. Phosphorus species, total nitrogen, and dissolved organic carbon concentrations generally peaked in mid- to late summer and were lowest in winter. For nitrate, the reverse was true. Nutrient concentrations generally were higher on the ebb tide than on the flood tide except for total dissolved phosphorus and total phosphorus where differences between flood and ebb tide depended on season. Constituent concentrations were similar between spring, neap, and midamplitude tides on both the flood and ebb tides. Nitrate, ammonium, total nitrogen, and silica concentrations were positively correlated with precipitation and runoff. Orthophosphate, total dissolved phosphorus, total phosphorus, and dissolved organic carbon were positively correlated with surface air temperature, downwelling shortwave radiation, and ocean water temperature. Nitrate, ammonium, and silica concentration were negatively correlated with surface air temperature and ocean water temperature. Orthophosphate and total dissolved phosphorus were negatively correlated with runoff. Nitrate plus nitrite, ammonium, and silica concentrations were negatively correlated with downwelling shortwave radiation.

Massachusetts↗

USGS2021

Assessment of water quality and discharge in the Herring River, Wellfleet, Massachusetts, November 2015 to September 2017

The U.S. Geological Survey, Cape Cod National Seashore of the National Park Service, and Friends of Herring River cooperated from 2015 to 2017 to assess nutrient concentrations and fluxes across the ocean-estuary boundary at a dike on the Herring River in Wellfleet, Massachusetts. The purpose of this assessment was to characterize environmental conditions prior to a future removal of the dike, which has restricted saltwater inputs into the Herring River watershed for more than 100 years. Water temperature, dissolved oxygen, pH, and specific conductance were monitored continuously, and flow-weighted composite samples were collected approximately twice per month at the ocean-estuary boundary. Bidirectional discharge was computed for the U.S. Geological Survey Herring River at Chequessett Neck Road at Wellfleet, Massachusetts, streamgage (011058798) by using a stage-area rating and index-velocity ratings developed with acoustic Doppler current profile measurements made upstream and downstream from the dike. LOADEST regression modeling software was used to estimate nutrient fluxes (loads) from composite, paired nutrient concentration and discharge data in conjunction with continuous discharge data. Temperature, dissolved oxygen, pH, and specific conductance were also monitored continuously on two tributaries to the Herring River, Pole Dike Creek and Bound Brook, from late-May 2016 to mid-June 2017. Composite or discrete water samples were collected from the tributaries approximately twice per month in most months from late-May 2016 to mid-June 2017 and analyzed for total nitrogen, total phosphorus, and dissolved organic carbon. Flow-weighted concentrations of ammonium, nitrate, and total nitrogen on the Herring River at the dike on the ebb tide generally varied between 0.01 and 0.1, 0.003 and 0.03, and 0.3 and 0.7 milligram per liter as nitrogen, respectively. Flow-weighted concentrations of orthophosphate, total dissolved phosphorus, and total phosphorus generally varied between 0.002 and 0.02, 0.003 and 0.06, and 0.03 and 0.1 milligram per liter as phosphorus, respectively, on the ebb tide. Flow-weighted concentrations of silicate and dissolved organic carbon on the ebb tide generally varied between 0.08 and 3.0 milligrams per liter of silica (silicon dioxide), and 1.7 and 5.6 milligrams per liter of carbon, respectively. Ebb tide concentrations of nitrate were highest in winter and lowest in summer. By contrast, ebb tide concentrations of phosphorus species were highest in late summer and early fall and lowest in winter. Silica and dissolved organic carbon did not exhibit systematic variation in seasonal concentrations. There was uncertainty in estimates of nutrient fluxes, but the LOADEST-estimated fluxes indicated that annual (and in almost all cases seasonal) exports (ebb tides) exceeded inputs (flood tides). Ebb tide concentrations of ammonium, nitrate, total nitrogen, and silica were positively correlated with antecedent cumulative 7-day precipitation.

Massachusetts↗