How Landsat Helps Utah: Water, Wildfire and Toxic Algae Seen From Space

Utah has a long list of notable features, and scenery tops it. In the southeast, the Colorado River winds through steep canyons cut in the eroded sedimentary rock that colors the Colorado Plateau — red arches, spires, hoodoos, cliffs and bridges that captivate residents and visitors. Mountain ranges add views, and skiing.

In the north, the Great Salt Lake is the largest saltwater lake in the Western Hemisphere. Western Utah, lake included, lies in the Great Basin, a multistate drainage with no outlet — so nothing flushes the salt out, and evaporation concentrates it (salinity). The lake has no fish, but supports algae and brine shrimp, and its wetlands draw millions of migratory birds.

Landsat satellite imagery shows surface changes such as the shallow lake's rising and falling water: it flooded in the 1980s, and its southern part hit its lowest level on record in 2021. Landsat can also look deeper into land and water conditions. Here's how it helps Utah.

Tracking water use

Long droughts have hit the whole western United States. In 2021, Lake Powell — the Colorado River reservoir on the Utah–Arizona border — fell to a historic low. The 2019 Colorado River Drought Contingency Plan, agreed by the seven Colorado Basin states including Utah, aims to reduce drought risk and sustain and protect the basin's water.

Lake Powell, behind Glen Canyon Dam, reaches from Arizona into Utah. The pale ring on the canyon walls is the lake's high-water mark; in 2021 it fell to its lowest level since the reservoir was filled. Wayne Baldwin, USGS

Utah has long relied on irrigation for its important farm industry. Landsat helps estimate how much water irrigation uses by measuring evapotranspiration (ET) — evaporation from soil plus transpiration from plants. The Utah Department of Natural Resources' Agricultural Water Optimization Task Force has recommended Landsat-based ET measurements as part of a more quantifiable way to administer irrigation water rights.

Wildfire information

Utah has hundreds of wildfires every year.

• LANDFIRE (Landscape Fire and Resource Management Planning Tools), a multi-agency partnership, maps vegetation types with Landsat and builds data layers that fire agencies, land managers and scientists use to understand the landscape and its fire vulnerability. The Utah Division of Forestry, Fire, and State Lands uses LANDFIRE data in its Utah Wildfire Risk Assessment Portal.
• Utah State University is building a Utah Fire Atlas from Landsat-based Monitoring Trends in Burn Severity maps of fires over 1,000 acres, plus its own maps of smaller fires from Landsat imagery going back to 1984.

The Dollar Ridge Fire burned nearly 70,000 acres in north central Utah in July 2018. Monitoring Trends in Burn Severity, USGS and U.S. Department of Agriculture Forest Service

Spotting toxic algae

Harmful algal blooms (HABs) — overgrowths of cyanobacteria in fresh water — produce toxins that can hurt people and animals and cost money. Satellites help officials find blooms sooner and watch large areas more easily.

In June 2017, Landsat imagery detected a bloom in Provo Bay of Utah Lake. Lab tests confirmed it, and the Utah Department of Environmental Quality issued a recreational advisory.

A deep green algal bloom on Utah Lake, June 20, 2017, in a natural-color Landsat 8 image. NASA and USGS

A later study by researchers at Georgetown University, Resources for the Future and the U.S. Environmental Protection Agency estimated that without satellites the bloom would likely have been found about 7 days later — and that in those 7 days about 8,000 visitors would have been exposed to toxins, costing an estimated $370,000 in medical care and lost productivity.

Landsat: national infrastructure

The USGS National Land Imaging Program provides satellite imagery and other remotely sensed and geospatial data to government, commercial, academic and public users, with worldwide access to Landsat data through the USGS Earth Resources Observation and Science (EROS) Center.

Landsat is the most widely used land remote-sensing data source in federal civilian agencies. Local, state, tribal and federal agencies use it to monitor and forecast what's happening on the land surface, and its information feeds everyday decisions on land, water and resources — protecting life and property, safeguarding the environment, advancing science, technology and education, supporting climate resilience, and growing the economy. It gives a landscape-scale view of changes on land, in inland lakes and on coasts, natural and human-made.

• Businesses build customer-specific applications on it for logistics, resource allocation and investment; commercial imaging firms use it to refine products.
• A 2017 USGS study put Landsat's total annual economic benefit to the U.S. at $2.06 billion — far more than it costs to build and run.
• Landsat 8 and 9 together cover Earth's land every 8 days. NASA and the USGS are reviewing a joint study that will shape Landsat Next, the successor to Landsat 9.
• Landsat 9 and its successors are meant to extend the 50-year Landsat record — the world's longest record of Earth's land surface.

Consistent, accurate data over the long term, with a no-cost data policy, let users study large areas and long-term change. New cloud computing and analytics tools put Landsat into decision-support systems for government and industry. Like global positioning systems and weather data, Landsat is used every day to understand our changing planet.

Sources

Based on U.S. Geological Survey, "Utah and Landsat," Fact Sheet 2022–3023, USGS (doi:10.3133/fs20223023); a work of the United States government in the public domain. Its opening section, missing from the imported copy, was restored from the USGS page. It cites Jacobs Engineering Group (2020), Ramsayer (2021), Straub and others (2019), Stroming and others (2020), the Utah Division of Forestry, Fire, and State Lands (2022) and the Utah Forest Institute (2020).