Studying Desert Water

Water cascades down high rocks into a desert pool
Waterfall in the Rincon Mountains

NPS/AWBiel

If you want to study water, you do not go to the Amazon or to Seattle. You come here, to the driest land. Nowhere else is it drawn to such a point. In the desert, water is unedited, perfect. ~Craig Childs, The Secret Knowledge of Water

Park staff and other experts study many aspects of the park's rare waters, including water quality, water chemistry, insects, plants, groundwater, flow patterns, and threats. Some of these projects are long-term monitoring and others short-term research studies but each one sheds new light on the hydrologic cycle at the park.

 
Green spotted frog sits at water's edge
Lowland leopard frogs (Rana yavapaiensis) rely on water resources in Saguaro National Park for their survival.
Photo by Erin Zylstra

Lowland Leopard Frog Surveys

Each spring and fall for the last twenty years members of the resource management team have walked up drainages in the park, stopping and sitting quietly at select tinajas. The deep, calm pools are perfect habitat for the lowland leopard frogs, a sensitive species. Park staff record the number of adults, tadpoles and egg masses they see in the pool before continuing to the next pool in the drainage. The surveys are an important tool to gauge the health of frog populations in the park and to understand the impact of events like drought and wildfire on the species. To learn about drought and survival and occupancy of this rare, desert-adapted aquatic frog, visit:

Isotope Studies

Although we know that all the water in the park comes from the mountains in the form of rain and snow it can be difficult to know how long the water takes to travel across the mountain front. We use isotopes - different masses of the same atom - to get a clearer picture of the water's origin and movement in the park. Water is collected from locations across the park like springs and tinajas and send to labs for testing. At the lab scientists look at the amount of oxygen, tritium and sulphur isotopes to determine the age of the water and if it fell during the summer or winter. These studies are important because they help the park make decisions about how to protect the watershed and the effect drought or wildfire might have on the springs.

 
Two people lay at the edge of a tinaja with measuring sticks
Park staff measure water height to monitor tinaja water levels over time.

Stream and Spring Monitoring

Survival in the Sonoran Desert is limited by available water. Many wildlife species depend on the park's streams, springs, and spring-fed pools that are locally called tinajas. Keeping track of these waters is important for their protection. Citizen-scientist volunteers who are willing to make a long-term commitment join park staff to collect monthly and bi-monthly data on streams, springs, and tinajas throughout the park. This multi-year project is an effort to better understand the water dynamics of the park, how and when they are used by wildlife, and how they respond to an ever-changing climate.

The Sonoran Desert Network also conducts long-term monitoring of the park's seeps, springs, and tinajas. Knowing about the status and trends of springs, seeps, and tinajas can provide park managers with early warning about potential threats to plants and animals that rely on these waters for survival. In some cases, identifying the condition of springs and seeps is also important for human health and safety. Knowing whether to expect surface water to be available at a given site is important to park visitors planning trips into the backcountry.

Saguaro National Park: Landscape of Desert Waters is a good introduction to information and research on park waters. This special booklet, supported by the Friends of Saguaro National Park, may take a few minutes to download, but is a great introduction to our water resources.

 
Local school group helping park staff with dragonfly survey.
Local school group helping park staff with dragonfly survey.

NPS photo/DJackson

Dragonfly Mercury Project

Citizen scientists in Saguaro National Park are joining citizen scientists across the nation in the Dragonfly Mercury Project to assess mercury levels in the park.

Mercury is a pollutant that can have serve impacts on human and wildlife health. The main human source of mercury in remote parks is coal burning power plants. The plants release mercury into the air whcih is eventually deposited on the landscape. Dragonfly larvae are good indicators of mercury in the food web because they live for a long time in the water as larvae and they are predatory, accumulating mercury from the other insects they eat. They are also an important source of food for birds and fish and so can indicate larger trends in the food chain. Citizen scientists at Saguaro National Park use dip nets to collect dragonfly larvae from tinajas, springs and creeks. The samples are analyzed and the data becomes part of a larger data set from parks across the country so scientists can understand larger trends in the landscape.

 
Bedrock pool under a blue sky, saguaros
One of the many tinajas monitored by staff and volunteers.

Last updated: May 9, 2022

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3693 S Old Spanish Trail
Tucson, AZ 85730

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520 733-5153
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