Hydrologic Cycle

The hydrologic cycle is the continuous circulation of water among the oceans, continents, and atmosphere. It can be thought of as a machine endlessly in motion, powered by the sun’s energy and assisted by gravity. Essentially the same water has been circulating in this machine since the first clouds formed and the first rains fell on Earth; very little is ever lost or gained.

The continents contain about 2.5 percent of our planet’s water, mainly in the polar ice caps and groundwater. The atmosphere accounts for only about 0.0001 percent. The oceans hold the remaining 97.5 percent of our planet’s water. About 90 percent of the water entering oceans is in the form of precipitation—rain and snow falling directly on the oceans. Runoff from the land accounts for the remaining 10 percent. The only significant outlet for ocean water is evaporation via the sun’s energy (heat).

Water evaporated into the atmosphere remains an average of only 10 days before being dropped as rain, snow, or condensation back into the oceans or onto the land. In general, water precipitated onto land can

  1. infiltrate into the ground,
  2. flow across the surface in a system of streams and lakes which eventually flows to the sea, or
  3. become glacial ice, eventually flowing to the sea.

Water that infiltrates into the ground may be used by plants, flow to nearby streams or lakes, or flow down to the water table where it becomes groundwater. Although we use the term “flow” to describe the motion of both groundwater and stream water, they have different characteristics. Groundwater flow occurs through pore spaces and fractures in sediment and rock, and is much slower and more dispersed than stream flow.

Read more about Groundwater and Aquifers

Of course, this is a simple description of a complex system and not all water travels completely through the cycle every time. Some water evaporates from streams and lakes, and even glacial ice, before reaching the sea, and plants use a relatively large amount of water and transfer it directly back to the atmosphere by a process called transpiration. While the system as a whole does not lose or gain water, the distribution in various parts of the cycle over different areas of the globe can change, causing floods and droughts.

Great Salt Lake, Wasatch Front, and Great Basin

Great Salt Lake, the Wasatch Front, and most of western Utah are in the Great Basin, a hydrologic region in the western U.S. that also includes most of Nevada and small parts of Idaho, Wyoming, Oregon, and California. In the Great Basin, surface water flows to land-locked basins—in other words, no streams flow to the oceans. Storm tracks coming primarily from the Pacific Ocean provide summer rainfall and winter snowfall that supply water to streams and lakes, but this water does not return to the Pacific Ocean unless it evaporates and falls directly on the ocean or as precipitation onto basins that drain to the ocean.

Great Salt Lake and the Wasatch Front create or have a hydrologic sub-cycle that contains many complexities and feedback loops. Great Salt Lake, through a process called “lake effect,” can increase precipitation along the Wasatch Front. At least two major phenomena control lake-effect precipitation: added moisture to the air due to evaporation from the lake’s surface, and atmospheric instability caused by the temperature contrast between the air and lake water. Evaporation from Great Salt Lake increases the moisture content of storms moving in from the Pacific Ocean. When these storms hit the Wasatch Range, the moisture moves upward and cools, causing precipitation (orographic effect). This combination of lake effect and orographic effect contributes to “the Greatest Snow on Earth” at the ski resorts in the Cottonwood Canyons and along the Wasatch Front.

Antelope Island & Farmington Bay, Great Salt Lake, Davis County, Utah Photographer: Ken Krahulec; © 2012

Antelope Island & Farmington Bay, Great Salt Lake, Davis County, Utah
Photographer: Ken Krahulec; © 2012

Highlighted Scientific Publications

Report of Investigation 282

Time Series Analyses of a Great Basin Groundwater-Fed Wetland Complex, Juab County, Utah: Climate Effects on Groundwater-Dependent Wetlands

Special Study 165

Characterization of the Groundwater System in Ogden Valley, Weber County, Utah, with Emphasis on Groundwater–Surface-Water Interaction and the Groundwater Budget

Public Interest Articles

Ricks Spring, Cache County Springs 2024
Climatically Controlled Water Supply in the Bryce Canyon Region? Groundwater 2024
The Utah Flux Network Groundwater 2022
Groundwater Monitoring Well Installation at Sevenmile Canyon Near Arches National Park Groundwater Monitoring 2021
The Role of Water Quality and Quantity on Future Development Near Bryce Canyon National Park Groundwater 2021
An In-depth Look at Ogden Valley's Groundwater Groundwater 2020
Crystal Geyser, Grand County Water 2018
Does Utah really use more water than any other state? Water 2018
Monroe’s “Sweet” Groundwater Points to Contamination Source Water 2018
Monitoring Groundwater Response to Large-Scale Juniper Treatments Water 2018
UGS’s Role in Contributing Water-Quality Data to the National Ground-Water Monitoring Network Groundwater 2017
Deep Nitrate in an Alluvial Valley: Potential Mechanisms for Transport Groundwater 2015
Roosevelt Hot Springs Geothermal Area, Beaver County Water 2014
UGS Groundwater & Spring Flow Monitoring in Snake Valley Groundwater 2014
Establishing Baseline Water Quality in the Southeastern Uinta Basin Water 2013
Using Aquifers for Water Storage in Cache Valley Water 2013
Gandy Warm Springs, Millard County Water 2013
What do environmental tracers tell us about groundwater in Snake Valley? Groundwater 2011
Modeling Ground-Water Flow in Cedar Valley Groundwater 2010
Utah Geological Survey’s West Desert Ground-Water Monitoring Network: Progress Report Groundwater 2010
Unusually High Nitrate Concentrations in Southern Sanpete County’s Ground Water Groundwater 2009
Cascade Springs, Wasatch County Water 2008
Geothermal Energy Development in Utah Geothermal Energy 2008
Ground-Water Monitoring in Utah’s West Desert Groundwater 2007
Proposed Ground-water Withdrawal in Snake Valley Groundwater 2006
Groundwater Water 2006
Pilot Project Shows Promise for Aquifer Storage and Recovery Groundwater 2005
The Midway Hot Pots – Natural Hot Springs, Wasatch County Water 2004
New Aquifer Storage and Recovery Project, Ogden Area Groundwater 2003
Cache Valley sensitivity and vulnerability to pesticides Groundwater 2002
Hydrologic Cycle Specific to Utah Water 1999
Do I have to travel all the way to Yellowstone, or can I see beautiful hot springs here in Utah? Water 1998
Thermal Springs in Utah Water 1995

Topic Articles: 33