Project Directors: Dr. Allan Frei, Simon Gruber

CISC has ongoing research projects associated with climate variations and water resources in the Hudson River Valley, just north of New York City. CISC Deputy Director Frei collaborates with CISC Fellow Simon Gruber looking at the potential impacts of climate change on water resources in the Hudson River Valley, as well as potential adaptation measures such as “green infrastructure.” CISC had a one year grant from the New York State Water Resources Institute to work with the Orange County Water Authority to support their inclusion of potential climate variations in the development of their long-term water plan. CISC continues to work in this area, and continues to seek additional funding to expand this area of research. The CISC Summer 2010 Climate Change Intern, Meredith Soniat, will contribute to this project by starting a GIS-based data base of water usage and green infrastructure projects in selected counties in the lower Hudson River Valley. CISC is also planning an event at Hunter College in Fall 2010 related to green infrastructure.

For more information contact: Dr. Allan Frei,

Allan Frei (Co-Primary Investigator), Simon Gruber (Co-Primary Investigator), Joseph Zurovchak, Carina Molnar, Shihyan Lee

City University of New York Institute for Sustainable Cities, Hunter College, NY, Private Consultant, Orange County, NY,  State University of New York, Orange County

Click here to download the final report.


Orange County, New York, is beginning to include the potential impacts of climate change in their long term water resource planning, but does not have the in-house technical expertise to review and interpret the current state of knowledge on climate change.


  1. to provide to the Orange County (OC) Water Authority (OCWA) assistance that they identify as necessary to begin to include climate change in  their planning process to meet their long-term water supply objectives. The goal is to ensure that plans include sufficient flexibility so that the community is prepared for, and can adapt to, climate change;
  2. to work with OC to perform outreach, which would help generate interest, disseminate information, and encourage input from OC residents;
  3. to use our experience with Orange County to develop materials that might be useful to other regional stakeholders.


    Based on the best available scientific understanding, we expect the following changes in the Hudson River Valley region by the end of the 21st Century:

  • Temperature and Precipitation Temperatures in this region are likely to increase. Precipitation changes are more uncertain (may either increase or decrease); a greater proportion of precipitation will likely fall in larger events.
  • Surface Water Under the most likely (67%) scenario, the mean annual surface water availability will not change significantly. However, there is a possibility that surface supplies will either increase or decrease.
  • Soils and groundwater will almost certainly be drier, possibly much drier. At the lower bound of the “most likely” (67%) range of scenarios, mean soil moisture and mean ground water levels may be diminished by 25% or more.
  • Extremes It is likely that this region will experience more frequent hot days and fewer cold days. The frequency of droughts in this region is unlikely to decrease, and may not change at all. However, if precipitation decreases, the frequency of droughts in this region may rise appreciably.
  • Outreach The Orange County students who participated in the preparation of outreach materials showed great enthusiasm and interest in this subject. We expect that the interest on the part of a wider audience will be similar.


  • Evaluate Water Demand Projections Development plans must consider the potential diminishment of water resources. Implement measures to maximize groundwater recharge, minimize surface runoff, reduce the need for irrigation, and manage and restore water and soil resources.
  • Maintain Familiarity with Major Climate Change Studies OCWA should keep abreast of the major climate change reports.
  • Keep Plans Flexible Plans for development must remain flexible in terms of supply and demand in order to account for the uncertainties.
  • Maintain links to Regional Partners One strategy for flexibility is to share water resources with other regional municipalities. This would involve shared risks as well as shared responsibilities.
  • Consider Effects on Water Quality It is likely that OC surface water resources will experience a higher proportion of large precipitation events, and that water temperatures will increase, with potential implications for water quality.
  • Monitoring OCWA should fund appropriate monitoring networks for water supply and quality. This will allow the county to accurately assess any changes that might occur during the coming decades.
  • Conduct Historical Analyses This analysis uses data from the Moodna Creek Watershed, which is available for only the last 10 years. This is too short a time period for climatological analyses: it is impossible to estimate what the true historical seasonal cycle, or total annual stream flow, actually was prior this the recent period. Also, we can not gauge how future changes might compare to historical precedents, such as the record drought of the 20th century that occurred in the early-mid 1960s.

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