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Hydrologic Investigation of Water Level Fluctuations at Moreau Lake, Moreau Lake State Park, Town of Moreau, New York

Scientific Investigations Report 2026-5132
Prepared in cooperation with New York State Department of Parks, Recreation and Historic Preservation
By:
https://doi.org/10.3133/sir20265132

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Abstract

The causes of water level fluctuations at Moreau Lake, within Moreau Lake State Park in the town of Moreau, New York, were investigated from 2016 to 2021 after lake water levels dropped between 2015 and 2016, raising concerns about the loss of a shallow swimming area at the park beach. Annual variation in precipitation records from the area did not account for the lake water level decline. Two possible causes for the low lake water levels were investigated: the increase in groundwater withdrawals from new residential development since about 2000 and seasonal changes (nongrowing and growing seasons) in precipitation.

Investigation of the potential effects of nearby groundwater withdrawals required the compilation and collection of well-log data, seismic surveys, and measurements of lake and groundwater levels, field chemical parameters, and water isotopes to define the hydrogeologic system and to estimate water use. The net result of this work was the determination that Moreau Lake is a “flow though” lake with no surface water outlet; groundwater enters the lake on the upgradient side and exits through the downgradient side, however, groundwater does not flow southward from the lake toward nearby groundwater withdrawals from the semiconfined aquifer, and thus groundwater withdrawals were unlikely to have an effect on lake water levels.

Investigation of the historic precipitation records during nongrowing (November through April) and growing (May through October) indicated that (1) nongrowing season precipitation from 2011–12 to 2015–16 was more deficient than any similar period during the past 78 years and (2) since about 2000, nongrowing seasons have been drier overall and growing seasons have been considerably wetter. Initiation of lake water level monitoring in 2016 provided an opportunity to compare seasonal precipitation with seasonal lake water level changes. Nongrowing season lake water levels are very sensitive to precipitation, such that high precipitation (40 percent above the seasonal median) resulted in a 5-foot rise in lake water level. In contrast, the growing season lake water levels are sensitive to dry conditions; for example, deficient rainfall (about 6 percent below the seasonal median) resulted in a decline of lake water levels of about 3.5 feet. However, lake water levels are insensitive to high growing season rainfall inputs (about 10 to 47 percent above the seasonal median); lake water levels consistently declined about by 0.8 feet above this range of seasonal excessive precipitation.

Suggested Citation

Heisig, P.M., 2026, Hydrologic investigation of water level fluctuations at Moreau Lake, Moreau Lake State Park, town of Moreau, New York: U.S. Geological Survey Scientific Investigations Report 2026–5132, 55 p., https://doi.org/10.3133/sir20265132.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Acknowledgments
  • Abstract
  • Introduction
  • Question 1—Do Increased Groundwater Withdrawals Since 2000 Contribute to Observed Lake Water Level Fluctuations?
  • Question 2—Do Seasonal Variations in Precipitation Account for Observed Lake-Level Fluctuations?
  • Summary
  • References Cited
Publication type Report
Publication Subtype USGS Numbered Series
Title Hydrologic investigation of water level fluctuations at Moreau Lake, Moreau Lake State Park, town of Moreau, New York
Series title Scientific Investigations Report
Series number 2026-5132
DOI 10.3133/sir20265132
Publication Date April 29, 2026
Year Published 2026
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) New York Water Science Center
Description Report: viii, 55 p., 3 Data Releases
Country United States
State New York
Other Geospatial Moreau Lake, Moreau Lake State Park, Town of Moreau
Online Only (Y/N) Y
Additional Online Files (Y/N) N
Additional publication details