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Dams and Sediment in the Hudson (DaSH)

In 2016, the Hudson River National Estuarine Research Reserve began a collaborative project with UMass, WHOI, and CBI entitled Dams and Sediment in the Hudson (or, DaSH).  The goal of this project, supported by NOAA NERRS Science Collaborative, is to quantify the effects of dam removal on sediment transport and wetland sustainability in the Hudson River Estuary.


DaSH logo


Hundreds of dams built on tributaries of the Hudson River estuary have altered the way that sediment moves through the system. Natural resource managers are now interested in removing some of these dams to improve connectivity of aquatic habitats, restore fish spawning habitat, and reduce risks of dam failures. A priority management need of the Hudson River National Estuarine Research Reserve was identified to improve the scientific understanding of the impacts that dam removals have on sediment transport and downstream tidal wetlands, including how these might change under future climate conditions.

This project addressed the needs identified by managers and regulators to assess the immediate impacts of sediment that is released when a dam is removed, as well as the longer term implications.

Water flows over a dam at Timor Park in a tributary of the Hudson River.

Timor Park Dam, photo credit: Andrew Meyer

The approach combined field observations with analysis of sediment movement using a proven hydrodynamic model. The project developed watershed assessment tools for permitting dam removals and established an improved scientific basis for considering the potential downstream benefits in regulatory decision-making.

Project Outcomes

  • Regulators have access to a new watershed assessment tool to help them evaluate the downstream impacts of dam removal.
  • Landowners, marsh managers, and federal and state restoration planners received training, project reports, and analysis tools to assess how dam removal will affect sediment conditions downstream.
  • Project findings and tools are available to resource and estuarine managers in similar systems through the links to the documents below:

DaSH Project Summary Documents

Project Overview: Download PDF

This document describes the purpose of the Dams and Sediment in the Hudson (DaSH) project, the functions of the Technical Team and Advisory Committee, and the results of the modeling and field work. It also includes a list of the project products, the main project findings, and potential next steps.

DaSH Impoundment Sediment Estimation Tool: Download PDF

This tool is designed to give dam owners and decision makers in the Lower Hudson River valley a method for assessing dam sediment inventories. It can also serve as a blue print for extension beyond the Hudson to the greater Northeast Region.

DaSH Sediment Trapping and Sediment Supply: Download PDF

This document explains the DaSH project findings on sediment. It includes a description of how sediment is transported through the watershed and becomes trapped behind dams, and how dam removals would affect sediment the Hudson River Estuary.

DaSH Rapid Tidal Marsh Growth: Download PDF

This document describes how tidal marshes in the Hudson River Estuary developed due to shoreline modifications. It explores the age of wetlands, human impacts to wetland development, and proposed future research to investigate why did some areas developed into marsh while others did not.

NERRS Science Collaborative Project Webpage


Presentations and Videos 

Brian Yellen gave a presentation on some of this research at the Edward A. Ames Seminar of the Hudson River Foundation in April, 2020.   


Hudson River National Estuarine Research Reserve

New York State Department of Environmental Conservation
NOAA National Estuarine Research Reserve System

Tivoli Bays Launch Closure – 2020

The canoe and kayak launch on the Kidd Lane access road at Tivoli Bays WMA is closed for renovations until further notice. At this time, DEC does not have an estimated completion date for the project. Please contact Nathan Ermer at 845-256-3047 for more information about this project. Thank you for your patience and understanding.