Are any of the plants and animals in our valley dependent upon the same groundwater we humans are? This is the question at the center of a $1M study created by a partnership of the Tubb Canyon Desert Conservancy (TCDC), the University of California, Irvine, and the San Diego Natural History Museum’s Department of Botany. This three-year study that will identify, assess, and monitor potential groundwater dependent ecosystems (GDE) in the Borrego Subbasin has been included as a major component of the Borrego Water District’s $5.6M spending plan approved by the California Department of Water Resources (DWR). The first phase of the project will determine if the Mesquite Bosque – a “potential groundwater dependent ecosystem” – located near the Borrego Sink is dependent upon groundwater from our aquifer for its survival. “Mesquite” is the common name for over 40 species of trees native to the Americas that are known to have extremely deep roots. “Bosque” is Spanish for forest or thicket.

TCDC President and Founding Director, J. David Garmon, M.D., hailed the funding of this project as a much-needed step in determining the impacts the drawdown of Borrego’s critically overdrafted aquifer have on the flora and fauna of Borrego Valley. “If the plants and animals of the Mesquite Bosque are found to be dependent on groundwater from our aquifer, then they are by definition Beneficial Users of water and their welfare must be considered in how we manage our groundwater,” Garmon said. The Sustainable Groundwater Management Act of 2014 defines groundwater dependent ecosystems as Beneficial Users of Water whose needs must be taken into account in the creation and implementation of Groundwater Management Plans (GMP).

Borrego’s current GMP asserts the declining Mesquite Bosque was once dependent upon groundwater for its survival, but that it no longer has its roots in the aquifer and therefore is not impacted by the human-caused drawdown of the aquifer. Borrego’s GMP (Appendix D4) acknowledges there is no scientific data to support such an assertion, and the GMP’s authors acknowledge that the denial of the existence of GDE’s in the Borrego Subbasin was a “strategic decision,” not a scientific conclusion, made at the time of the writing of our GMP.

Mark Jorgenson, former ABDSP Superintendent and current Community Representative to the Borrego Watermaster Board has long contended the surviving Mesquite Bosque, and its associated plants and animals, continue to live because of the mesquites’ deep roots that reach groundwater. Jorgensen said, “This project is an opportunity to see if that is true or not. The funding provided by DWR will allow us to use the most up-to-date scientific methods, employed by nationally recognized scientists, to see if the Mesquite Bosque is, or is not, dependent on groundwater; and therefore is, or is not, impacted by the implementation of our GMP. We will see where the science leads.”

TCDC Vice President and Founding Director, Robert Staehle, led TCDC’s writing team. He said, “We are pleased our project is among the seven proposals funded, out of the 15 proposals originally submitted to the Borrego Water District in December 2021.” Selections were made using a Project Review Committee process overseen by the Borrego Water District. Staehle added, “This project will bring scientific rigor to one of the most important outstanding environmental questions in the Borrego Subbasin: Are any of the plants and animals in our valley dependent upon the same groundwater we humans are? If so, they must be included in our decisions about how we manage our water so the needs of all Beneficial Users of water are taken into account, as required by the Sustainable Groundwater Management Act. We look forward to working with the Water District, the Watermaster, the Borrego community, and the other awardees as we all grapple with the challenges of ensuring the sustainability of our precious and vulnerable desert.”

The Tubb Canyon Desert Conservancy is a non-profit, public benefit corporation established in 2011 to preserve habitat and biodiversity, protect native plants and wildlife, and conserve scenic vistas and historic sites in the vicinity of Tubb Canyon and the larger Anza-Borrego Sonoran Desert in southeastern California.

For more information visit http://www.tubbcanyondesertconservancy.org