Hydrodynamics2019-09-16T12:36:19-04:00

Transfer of a low-cost tidal wetland water level monitoring system: hyperlocal calculations of inundation and tidal datums for understanding change and restoration planning

Title: Transfer of a low-cost tidal wetland water level monitoring system: hyperlocal calculations of inundation and tidal datums for understanding change and restoration planning

Affiliation: Okeanolog/WBNERR

Funding Source:  NERRS Science Collaborative Science Transfer gran

Contact/Email: Megan Tyrrell, Research Coordinator, WBNERR (megan.tyrrell@mass.gov)

Abstract: Waquoit Bay Reserve ongoing water level monitoring program focusing on discrete salt marsh microhabitats and employing a simple and inexpensive system of water level monitoring developed by PI Vitalii Sheremet. The ‘Arm-and-Float’ water level instrument uses a HOBO Pendant G accelerometer. These easy to deploy loggers have been used in several types of salt marsh habitats (e.g., pools, creeks and upstream of a tidal restriction) at WBNERR and other NERRs.

The principle of operation is based on converting the raw signal of the arm tilt into the elevation of the float relative to a fixed pivot by multiplication by the arm length. In this way, accuracy of 5-10 mm is achieved, which is adequate for calculating tidal datums for each feature where the logger is deployed. In May 2021, 20 arm-and-float loggers were deployed across Sage Lot Pond for water level monitoring in conjunction with seven other Reserves spanning a range of climactic and tidal regimes which also received arm-and-float loggers as part of the science transfer grant. At the conclusion of this project, locally relevant tidal datums will be calculated, and enhanced understanding of the differences in inundation regime for 20 salt marsh features including creeks, pools, nascent pools, surrounding potential tidal restrictions will be available.

Evaluating the Impact of Hydrologic Alterations on Salt Marsh Sustainability in a Changing Climate

Project Title: Evaluating the Impact of Hydrologic Alterations on Salt Marsh Sustainability in a Changing Climate

Project Partners: Cape Cod Mosquito Control Project, Louisiana State University, National Park Service, United States Fish and Wildlife Service, Rachel Carson National Wildlife Refuge, United States Geologic Survey, Waquoit Bay National Estuarine Research Reserve, Woods Hole Oceanographic Institution

Coastal managers are faced with the challenge of managing marsh hydrology in a way that meets human health needs, optimizes ecosystem services, and supports sustainability. In New England this includes accounting for the effects of ditches that were dug decades ago in 90% of the region’s salt marshes.

Ditches increase marsh drainage and reduce the spatial extent of shallow pools that may represent physical loss of buried soil carbon. However, efficient drainage may reduce the long-term sustainability of marshes by altering below ground biogeochemical and physical processes in a way that results in subsidence and lowered marsh elevation. Managers, restoration practitioners, and scientists at the Waquoit Bay National Estuarine Research Reserve, Woods Hole Oceanographic Institution, U.S. Geological Survey, U.S. Fish and Wildlife Service, National Park Service, and the Cape Cod Mosquito Control Project have expressed a need to understand the tradeoffs of hydrologic management strategies (i.e., ditch remediation, density, maintenance) and identify actions that will achieve user-specified outcomes— such as drainage, maintaining elevation, and carbon burial.

Products:
FACT SHEET: Project Overview
WHOI Website: Marsh Sustainability & Hydrology
Marshes, Mosquitos & Sea Level Rise-Oceanus Magazine Video Link

Marsh Sustainability and Hydrology (MSH) Project Webinar
October 2020
The MSH project is a collaborative research effort involving partners from the University of Georgia, Woods Hole Oceanographic Institution, Louisiana State University, United States Geological Survey, Cape Cod Mosquito Control,  US Fish and Wildlife Service, National Park Service and the Waquoit Bay National Estuarine Research Reserve.

Coastal resource managers are tasked with making decisions that simultaneously address the welfare of local communities and the sustainability of salt marshes and the valuable ecosystem services they support. In New England, anthropogenic ditches were dug to reduce shallow ponds on the marsh platform where mosquitos breed, although this may have led to unintended consequences such as lower elevations and increased susceptibility to sea-level rise. In order to evaluate the net impacts of ditching to carbon storage and elevation resilience, we collected cores from the ditched and unditched sections of Great Barnstable Marsh (MA, USA) and measured and compared accretion rates, soil properties, soil organic carbon and ages to determine impact of ditching on marsh sustainability to sea level rise. A geomorphic model calibrated with field data was used to develop a decision support tool to help managers assess impact of different management strategies on salt marsh sustainability and ecosystem service delivery.

To view the workshop presentations please go to: Marsh Sustainability and Hydrology Project Webinar Presentation Videos

MSH Team Members:
Amanda Spivak, Principal Investigator, University of Georgia
Sheron Luk, PhD Student, Woods Hole Oceanographic Institution
Meagan Eagle, United States Geological Survey
Gabrielle Sakolsky, Director, Cape Cod Mosquito Control
Susan Adamovich, US Fish and Wildlife Service
Giulio Mariotti, Louisiana State University
Megan Tyrrell, Research Coordinator, Waquoit Bay National Estuarine Research Reserve
Tonna-Marie Surgeon Rogers, Director, Waquoit Bay National Estuarine Research Reserve

Land–sea coupling and global-driven forcing: following some of Scott Nixon’s challenges

Project Title: Land–sea coupling and global-driven forcing: following some of Scott Nixon’s challenges

Date: 2015

Principal Investigator(s): Valiela, I. & Bartholomew, M.

Summary: Adjoined watershed–estuary–coastal ecosystems are coupled by biogeochemical and hydrodynamic processes, as Scott Nixon repeatedly argued in his many contributions. Case histories from Waquoit Bay and the Pacific Coast of Panama, supplemented by information from other sites, make evident that the couplings that enable connectivity among spatially separate landscape units, while highly subject to detailed local contingencies, take place in every coastal zone, can be powerfully affected by human activities on land, and by global-scale forcings, as Scott Nixon often reminded us. Read full text…Estuaries and Coasts 38: 1189. doi:10.1007/s12237-01498083. https://link.springer.com/article/10.1007/s12237-014-9808-3

Development of Low-cost, In-situ, Precision Hydrodynamic Instrumentation for Measurement of Tides, Currents and Waves

Project Title: Development of Low-cost, In-situ, Precision Hydrodynamic Instrumentation for Measurement of Tides, Currents and Waves

PI: Vitalii Sheremet, University of RI, NOAA NMFS Research Fellow

Funding: NOAA NMFS Research Fellowship, WBNERR collaborative in-kind

Summary: An inexpensive current meter based on the drag principle is being designed and developed. It provides a simple, elegant, robust, and low-cost solution for measuring currents at the ocean bottom or from any fixed platform. Its operation is based on the drag law of a buoyant tethered cylinder in flowing water. Three-axis accelerometers measure tilts which are converted to a horizontal velocity vector. Special tethered attachment enables estimation of not only the magnitude but also horizontal direction of the current. The same accelerometers are also used to construct a simple stick-and-float tide gauge.

The performance of the instruments is being evaluated in field tests in Waquoit Bay and Nantucket Sound. Arrays of the instruments deployed for periods from days to months are used to record tidal and higher frequency oscillations in the Waquoit Bay. A dramatic double peaked flood (double height) tide arising from nonlinear interaction with bathymetry is studied. Strong seiches with periods of about 15-30 minutes are also recorded in some parts of the Waquoit Bay system.

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