Evaporation from Lake Mead and Lake Mohave, Nevada and Arizona, 2010–2019

Open-File Report 2021-1022
Water Availability and Use Science Program
Prepared in cooperation with the Bureau of Reclamation
By:  and 



Evaporation-rate estimates at Lake Mead and Lake Mohave, Nevada and Arizona, were based on eddy covariance and available energy measurements from March 2010 through April 2019 at Lake Mead and May 2013 through April 2019 at Lake Mohave. The continuous data needed to compute monthly evaporation were collected from floating-platform and land-based measurement stations located at each reservoir. Collected data include latent- and sensible-heat fluxes, net radiation, air temperature, wind speed, humidity, and water-temperature profiles. Data collection, analysis methods, and monthly evaporation results for Lake Mead through February 2012 were documented in a U.S. Geological Survey (USGS) Scientific-Investigations Report, 2013–5229. Monthly evaporation and associated datasets for both reservoirs through April 2015 were published in a USGS Data Release (https://doi.org/10.5066/F79C6VG3). Average annual evaporation at Lake Mead was 1,896 millimeters (mm), which is a 10 percent difference from the 1,718 mm average annual evaporation at Lake Mohave; this was primarily due to differences in available energy. Average annual available energy at Lake Mead was 139 watts per square meter (W/m2), which is an 18 percent difference from the 116 W/m2 average annual available energy at Lake Mohave. Differences in available energy are driven by differences in advected heat between Lake Mead and Lake Mohave; advected heat at Lake Mohave is lower due to colder inflows and warmer outflows. Lake Mead monthly evaporation estimates for this study compare reasonably well to the Bureau of Reclamation’s 24-Month Study (24MS) evaporation coefficients, which are based on pioneering studies from the 1950s. Temporal trends in this study indicate that the effects of heat storage at Lake Mead were underestimated in the 24MS, particularly during the fall months when energy was released from the lake. Mean monthly evaporation rates at Lake Mead were greater than Lake Mohave from June through November during the study period. The seasonal pattern of evaporation at Lake Mohave in this study indicates that the effects of available energy were underestimated in the 24MS coefficients for this reservoir, and that evaporation was substantially overestimated from spring through summer
during the study period of 2013 through 2019.

Suggested Citation

Earp, K.J., and Moreo, M.T., 2021, Evaporation from Lake Mead and Lake Mohave, Nevada and Arizona, 2010–2019: U.S. Geological Survey Open-File Report 2021–1022, 36 p., https://doi.org/10.3133/ofr20211022.

ISSN: 2331-1258 (online)

Study Area

Table of Contents

  • Abstract
  • Introduction
  • Methods of Study
  • Evaporation from Lake Mead and Lake Mohave
  • References Cited
Publication type Report
Publication Subtype USGS Numbered Series
Title Evaporation from Lake Mead and Lake Mohave, Nevada and Arizona, 2010–2019
Series title Open-File Report
Series number 2021-1022
DOI 10.3133/ofr20211022
Year Published 2021
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Nevada Water Science Center
Description vii, 36 p.
Country United States
State Arizona, Nevada
Other Geospatial Lake Mead, Lake Mohave
Online Only (Y/N) Y
Google Analytic Metrics Metrics page
Additional publication details