The science of turning a dry riverbed into an oasis

Laura Norman stood beside a trickling stream, taking in the enchanting scenery around her. The scenery was lush, green even, but Norman was not standing in a tropical paradise. In fact, her oasis was located in one of the driest and hottest regions in the world, and a few years ago, there was almost no vegetation in this gully.

Norman has studied watersheds for more than 20 years in arid and semiarid regions of the southwestern United States, where land use change and climate change are causing increasing desertification. Yet, where she stood, as if by magic, permanent wetlands appeared.

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

The simple technology Norman and her team employed is a nature-based solution they call Natural Infrastructure for Dry Streams (NIDS). Essentially, NIDS are structures made of rock, wood or earth that are built by humans or reintroduced beavers over the flow of water in a gully, creek or stream.

The NIDS structures she studies look like dams, but they don’t store water; they just slow its flow. They are essentially detention structures, not reservoirs.

Norman studied these detention facilities as part of her long-term research Water harvesting research in arid areas. Although simple, they have many benefits.

Slowing water flows reduces erosion and gives water time to seep into the ground, replenishing underground reservoirs or aquifers. While slowing water flows, counterintuitively, they can raise water levels downstream.

These retention structures also trap sediment, improve downstream water quality, and provide a substrate for plants to take root. Once in place, the wetland ecosystems formed around the NIDS will further reduce erosion and support wildlife.

Norman’s extensive research on NIDS shows that their impacts at the landscape level can be Helping combat desertification and building climate resilience In the southwest.

It may be hard for people to imagine that something as simple as a pile of rocks or logs in a riverbed could have such a big impact, but this is a common feature of nature-based solutions.

Other examples of nature-based solutions include restoring coastal wetlands to control flooding and soil erosion; restoring oyster and coral reefs to protect against storm surges; and adding urban trees and green spaces to reduce ambient temperatures.

But as Norman’s work on NIDS demonstrates, the real beauty of nature-based solutions is that their benefits extend far beyond what they can do to directly protect human communities.

There are nature-based solutions that can increase biodiversity. Increased carbon storage and lower greenhouse gas emissions, reduce energy and water use, and provide other ecosystem services to humans, such as crop pollination.

With so many advantages, it’s no wonder that the USGS research team includes scientists like Norman who research nature-based solutions.

Scientists such as Martha Sauer, Ken Krauss and Peter Ibsen study how forests can mitigate droughts, how coastal wetlands can reduce the intensity of ocean waves and how trees and grasses can cool cities, respectively. Others, such as Patrick Barnard, Kurt Storlach, Ilsa Kuffner and Lauren Toth, study how restoring ecosystems such as coastal wetlands and coral reefs can help mitigate the effects of climate change, such as rising sea levels.

Scientists at the Southeast Climate Adaptation Science Center even worked with other Interior Department staff to create a DOI Nature-Based Solutions RoadmapIt provides DOI staff with reliable information and resources related to nature-based solutions, including examples of projects from across the country.

Although the term is relatively new, people have been using natural elements to modify or maintain ecosystems for the benefit of humanity since ancient times. Given this fact, the DOI Nature-Based Solutions Roadmap includes indigenous knowledge.

Norman herself works with tribes and indigenous peoples in the Southwest, whose communities have thrived in this extremely dry and hot region for thousands of years. Among other things, she collaborates with them to learn from traditional practices and to develop, implement and improve nature-based solutions, particularly as they relate to water harvesting.

For example, Norman worked with the San Carlos Apache Reservation to study watersheds and water collection. The knowledge they gained from their research is now being passed on. Students from the San Carlos Apache Reservation recently participated in a field day. They learned about watersheds and applied water harvesting practices.

Likewise, Norman recently traveled to La Paz, Baja California Sur, Mexico, to share her work and co-host an event for students. On March 11, 2024, Norman and other USGS scientists worked with partners such as local academics to host a ““Water Festival Road” A total of 115 local middle and high school students participated.

Norman recalls watching young people learning about water harvesting, and he is filled with a sense of achievement and hope for the future. The use of NIDS for water harvesting—something many were once skeptical of—is gaining widespread popularity, even influencing young people to learn basic lessons about the world around them. These lessons lay the foundation 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, it doesn’t mean Norman’s work is done. She will continue to work on viable watershed-related research and continue to learn and share findings about the benefits of nature-based solutions like NIDS.