USGS: The science that transformed a dry streambed into an oasis

Nature-based solutions may seem too-good-to-be-true, but USGS is studying how these simple solutions provide benefits for people and the environment.

Laura Norman stood by the trickling stream and let the enchantment of her surroundings wash over her. The landscape was verdant, lush even, but Norman wasn’t standing in a tropical paradise. In fact, her oasis was in one of the driest, hottest regions in the world, and only a handful of years ago, this gully was virtually barren of plants.

In the arid and semi-arid southwestern United States, where Norman has studied watersheds for over 20 years, land use changes and climate change are causing increasing desertification. And yet where she stood, as if by magic, permanent wetlands had sprung up.

But it wasn’t a spell or a massive feat of engineering that caused moisture to seep into the land, allowing plants to grow and creating habitat for aquatic animals. It was simple technology that when carefully applied, allowed the laws of nature to transform the land.

Infographic explaining the benefits of Natural Infrastructure in Dryland Steams.

The simple technology Norman and her team used was a type of nature-based solution they call Natural Infrastructure in Dryland Streams, or NIDS. Essentially, NIDS are structures made of rock, wood or mud that people or reintroduced beavers construct across the flow of water in a gully, creek or stream.

The NIDS structures she studies seem like dams, but they don’t retain water, they merely slow it down. They are basically detention structures, not impoundments.

Norman studies these detention structures as part of her long-term Aridlands Water Harvesting Study. While simple, they have many benefits.

Slowing the flow decreases erosion and allows the water time to seep into the ground where it can recharge underground reservoirs, or aquifers. Although they slow the flow, counterintuitively they increase downstream water levels.

These detention structures also trap sediment, improving downstream water quality and creating substrate in which plants can take root. Once in place, the wetland ecosystems that form around NIDS further decrease erosion and support wildlife.

Norman’s substantial research on NIDS shows the landscape-level effects they have can help to combat desertification and increase climate resilience in the Southwest.

It may be hard to fathom that something as simple as a pile of rocks or logs across a streambed could have such an outsized impact, but that is a common feature of nature-based solutions.

Examples of other nature-based solutions include restoring coastal wetlands for flood and erosion control; restoring oyster and coral reefs for storm surge protection; and increasing trees and greenspace in urban settings to lower ambient temperatures.

But, as evidenced by Norman’s work on NIDS, the true beauty of nature-based solutions is that their benefits far exceed what they can do to directly protect human communities.
 Outline of United States, AK, & HI, with cartoons illustrating nature-based solutions spread across the country.

There are examples of nature-based solutions increasing biodiversity, increasing carbon storage and lower greenhouse gas emissions, decreasing energy and water use and providing other ecosystem services to people, like crop pollination.

With such a large pool of advantages, it’s no wonder that the USGS research portfolio includes scientists, like Norman, who study nature-based solutions.

Scientists like Martha Scholl, Ken Kraus and Peter Ibsen study how forests can mitigate drought, how coastal wetlands can reduce wave severity and how trees and grass can lower urban heat, respectively. Others, like Patrick Barnard, Curt Storlazzi, Ilsa Kuffner and Lauren Toth study how restoring ecosystems like coastal wetlands and coral reefs can help to mitigate the effects of climate change, like sea level rise.

Scientists with the Southeast Climate Adaptation Science Center even worked alongside other Department of the Interior staff to create a DOI Nature-based Solutions Roadmap, which provides DOI staff with reliable information and resources related to nature-based solutions, including examples of projects from around the nation.

Although the term is relatively new, people have been using elements of nature to modify or maintain ecosystems for our benefit for time immemorial. In recognition of this fact, the DOI Nature-based Solutions Roadmap includes Indigenous Knowledges.

Norman herself works with Tribes and indigenous peoples in the Southwest whose communities have thrived in this incredibly dry and hot region for thousands of years. Among other things, she partners with them to learn traditional practices and develop, implement and refine nature-based solutions, particularly related to water harvesting.

For example, Norman has partnered with the San Carlos Apache Reservation to study watersheds and water harvesting. The knowledge gained from their research is now being passed on. Students of the San Carlos Apache Reservation recently participated in a field day where they learned about watersheds and employing the practice of water harvesting.

Several people stand talking around a table covered in pamphlets and a laptop under a thatched, open air pavilion
Laura Norman with students at the Festival Caminos del Agua.

Likewise, Norman recently traveled to La Paz, Baja California Sur, Mexico to share her work and co-host an event geared toward students. On March 11, 2024, Norman and other USGS scientists worked with partners, including local academics, to hold a “Festival Caminos Del Agua” (Paths of Water Festival) in which 115 local middle and high school students participated.

Reflecting on watching young people learning about water harvesting, Norman is flooded by a sense of accomplishment and hope for the future. The practice of water harvesting with NIDS—something many were once skeptical about—is being embraced to the extent that is has rippled into the foundational lessons young people are learning about the world around them. These lessons lay the groundwork for a future where nature and people thrive together.

But just because NIDS and water harvesting have gained some support and understanding in the region doesn’t mean Norman’s work is done. She’ll continue to immerse herself in actionable watershed-related research and continue to learn and share findings about the benefits of nature-based solutions like NIDS.