Evaluating trends in streamflow extremes in the Northeast USA

Project Leader: 
Research Partners: 
Dr. Austin Polebitski (University of Wisconsin-Platteville), Joshua Roundy (Civil and Environmental Engineering/ Princeton University), MA Department of Transportation, The Nature Conservancy
Project Fellows: 
Status: 
Ongoing
Science Themes: 
Climate impacts on freshwater resources and ecosystems

The goal of this project is to identify statistical trends in observed and simulated maximum, minimum and base (mostly groundwater contribution during low flow months) flows in the Northeast Climate Science Center domain during the 20th and 21st century, assess the temporal (annual and seasonal) and spatial distribution of the trends, and evaluate the impact of warmer climates on the statistical properties of streamflows (mean and variance). A secondary goal is to determine what GCMs best represent the observed climatology of the region using statistical metrics.

Base and minimum flows are vital for fish ecosystem functioning and for riparian vegetation. Climate projections indicate summers will get warmer and drier in the NE CSC domain which will affect aquatic ecosystems. Larger streamflows peaks will affect existing infrastructure, e.g. bridges, dams, cities).  

Keith Kuk-Hyun Ahn completed a non stationary analysis for streamflow in the connecticut river basin, developing regional flood frequency analysis using spatial proximity and basin characteristics in the northeastern United States, and developed drought forecasting methodology using climate indices. He also built the SWAT model for Deerfield basins.

Nirajan Dhakal's findings include the following:

  1. The high and low flow seasonality of catchments in the northeastern Unites States is likely to change under climate change because of anticipated alterations of precipitation as well as snow accumulation and melt. Information on this change is crucial for flood protection polices for example for regional flood frequency analysis. The objective of this study is to evaluate the change in seasonality of daily stream flows (both high and low) in northeastern Unites States.                                                                                                       
  2. In areas where high flows are generated by more than one distinct hydrologic process (e.g., snowmelt- and rainfall generated peaks), peak discharge data should be considered to be drawn from subpopulations with different statistical characteristics. For an appropriate and effective hydrologic design it is necessary to consider these two characteristics of precipitation to estimate the probability distribution by introducing mixed distribution.

 

Publications: 
Presentations: 

  • Richard Palmer, PE, Ph.D., F ASCE, D.WRE, University of Massachusetts; David Ahlfeld, Ph.D., University of Massachusetts; Rachael Weiter, B.S., University of Massachusetts; Gordon Clark, B.S., University of Massachusetts. Developing a Screening Model for the Prioritization of Culvert Repair and Replacement. ASCE EWRI Conference, Austin, TX. May 2015. 

Other: 
  • Finished a distributed model (WR-hydro) for the deerfield, this model include NARCCAP projections to assess potential high flow impacts, now we are preparing a publication for this study.                                                                                                                                                                                   
  • We are in the phase of calibrating a hidrology model that covers the northeast of the US from Virginia to Maine in a 3 km resolution to quantify  impact  of climate change in the hydrology of the region.
  • Forecasting informed Hierarchical Bayesian modeling for low-flow in the east U.S. (December, 2015)
  • Related project: The NE CSC's NorEaST Stream Temperature Inventory and Web Portal project
  • Related project: UMass Extension's River and Stream Continuity project
  • Related project: North Atlantic LCC's Restoring Aquatic Connectivity and Increasing Resilience project