collaborative research at the Reserve

Dams and Sediment in the Hudson

The state of New York is working to remove hundreds of dams built on tributaries of the Hudson River estuary.

When dams are removed, sediment trapped behind them will be released into the estuary.

Through the Dams and Sediment in the Hudson (DaSH) project, the Hudson River Reserve brought scientists and stakeholders together to investigate the question:

How will these sediments affect the estuary and its tidal marshes? 

Dams and Sediment in the Hudson (DaSH) becan in 2016 with a collaborative project, supported by NOAA NERRS Science Collaborative, designed to quantify the effects of dam removal on sediment transport and wetland sustainability in the Hudson River Estuary.

The project used a multidisciplinary approach that combined field observations with an analysis of sediment transport using a proven hydrodynamic model. A broad coalition of stakeholders from state agencies, engineering firms, and environmental restoration organizations guided the research and its final products. 

DaSH answered key questions about how dam removal will impact conditions in the estuary and offered surprising new findings about tidal marshes in the Hudson River valley. The project found that the amount of sediment that could be released by dam removal is minimal compared to background sediment supply from the watershed. Dam removals would have a minimal impact on both sediment supply to the estuary and tidal wetland growth. The project developed watershed assessment tools to support dam removal permitting and established an improved scientific basis to consider potential downstream benefits in regulatory decision-making.

project documents

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.

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.

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.

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.


Presented via the NERRS Science Collaborative.

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


  • McKeon K, Woodruff JD, Yellen B, Fernald SH, Sheehan MC. 2021. Invasive water chestnut hinders tidal wetland development. Earth Surf. Process. Landforms. 2022;1-16. AVAILABLE HERE
  • Ralston DK, Yellen B, Woodruff JD. 2020. Watershed suspended sediment supply and potential impacts of dam removals for an estuary. Estuaries and Coasts. 44, 1195-1215 (2021). AVAILABLE HERE
  • Ralston DK, Yellen B, Woodruff JD, Fernald S. 2020. Turbidity
    hysteresis in an estuary and tidal river following an extreme discharge event. Geophysical Research Letters, 46, e2020GL088005.
  • Yellen B, Woodruff JD, Ladlow C, Ralston DK, Fernald S, Lau W. 2021. Rapid tidal marsh development in anthropogenic backwaters. Earth Surf. Process. Landforms. 2021;1–20. AVAILABLE HERE