Conservation of the Santa Cruz River
The importance of the Santa Cruz River to the citizens of Santa Cruz County and greater Southeast Arizona has made its conservation a high priority for many organizations. There has been much recent progress in river conservation, both in Tubac and for the watershed throughout Santa Cruz and Pima Counties. Tubac Nature Center has been active in these efforts and is bringing a focus to the river and lands along it in Tubac. Click below for general information about the Santa Cruz River.
Monsoon over the Santa Cruz River
Santa Cruz River National Wildlife Refuge?
The establishment of a National Wildlife Refuge for the lands near the Santa Cruz River in Santa Cruz and Pima Counties would preserve many miles of river and thousands of acres of land. The Santa Cruz River Coalition is working to support the establishment of the Santa Cruz River Wildlife Refuge. The Nature Center is an active member of the Coalition. The U.S. Fish and Wildlife Service could designate a National Wildlife Refuge in the future. The Sonoran Institute, one of the organizations leading the Coalition, is conducting studies that will support establishment of the refuge. The Coalition is also exploring other options for land preservation along the river.
Tubac Nature Center Conservation Projects
Tubac Nature Center is guiding efforts to preserve and restore the Santa Cruz River and its associated habitats in Tubac. Our efforts aim to enhance ecological and passive recreational values, and will support the preservation of the land. We are working with the landowner and engaging the community. We have received grants worth approximately $120,000 thus far, and are partnering with the Tucson Bird Alliance on these projects.
Tubac Nature Preserve Conceptual Master Plan
In 2023, Tubac Nature Center released a report that serves as a blueprint for the conservation of the river lands in Tubac. This plan is guiding our efforts, and should guide all future efforts for the land. A community workshop involving over 100 participants was held in February 2023 to gain community input that was used to prepare the final Conceptual Master Plan.
Tubac Borrow Pit Wetland Restoration Plan
The Tubac Borrow Pit was excavated in the early 2000s to provide fill to develop the adjacent Barrio de Tubac community. The excavation reached groundwater, which resulted in the development of a wetland and associated riparian habitat that supported many birds and wildlife. The habitat has since degraded due to multiple factors including declining groundwater levels and the establishment of non-native invasive plants such as tamarisk (salt cedar). Wetlands are rare and of exceptional ecological significance in Southeast Arizona, so restoration is a top priority. In 2023, we received a grant from the Santa Cruz Valley National Heritage Area (SCVNHA) to develop a restoration plan for the wetlands in the Tubac Borrow Pit. As part of this grant, the Tucson Bird Alliance began the task of removing tamarisk in the Borrow Pit. Also as part of this grant, we installed an interpretive sign near the Borrow Pit that explains the ecological significance of the Borrow Pit habitats.
Riparian Forest and Grassland Evaluation and Restoration Plan
The 2023 Conceptual Plan identified the cottonwood-willow riparian forest and grasslands as the two other priority Santa Cruz River habitats for restoration. Of particular concern is that riverbank erosion and declining groundwater levels, as well as grazing, are inhibiting the growth of saplings into trees. Over time, as older trees die, this could cause the loss of the forest. In 2024, The Nature Center received another grant from SCVNHA to develop a restoration plan for these two habitats. The grant also supported monthly volunteer work events run by the Tucson Bird Alliance, to remove invasive grasses around the Tubac Borrow Pit. The monthly work events are continuing.
Control of Invasive Trees and Grasses in the Santa Cruz River Floodplain
In 2025, Tubac Nature Center received a grant from the Arizona Department of Forestry and Fire Management (DFFM) Invasive Plant Grant Program to continue our invasive plant control efforts for the next three years. This continued work is essential to the ultimate success of the wetland restoration project for the Tubac Borrow Pit, as well as for the health of the broader ecosystem.
Borrow Pit Monitoring
Understanding the hydrology of the Borrow Pit is critical for designing the habitat restoration project. The water level in the Borrow Pit, and how it changes seasonally, will help determine the characteristics of the wetland and associated vegetation that can be sustained. Treated sewage effluent is discharged to the Borrow Pit from the nearby Baca Float Wastewater Treatment Plant in seasonally varying amounts. This is likely a key factor influencing groundwater levels. Conversely, as part of the restoration project, there may be opportunity to retain the discharged water at the surface to support the wetland. The Nature Center entered into a $5000 contract with the Tucson Bird Alliance to install a Johnson well (pictured at right) to allow measurement of groundwater levels, and a flow meter on the effluent discharge pipe. Monthly data collection began in winter 2026 and will continue into 2027.
Borrow Pit Stormwater Harvesting
The Tubac Borrow Pit Wetland Restoration Plan report recommends several restoration project components to increase the amount of water the borrow pit receives from rainfall runoff. One of these is to divert stormwater runoff from the Market Circle neighborhood of the Barrio de Tubac, west of the Borrow Pit. Tucson Bird Alliance constructed a “rolling dip” (a portion of which is pictured at left) to channel stormwater runoff from the existing drainage channel into the pit. A rolling dip is a gentle, smooth depression, often with a reverse-grade, built into unpaved roads, trails or paths, to shed stormwater runoff while preventing it from building damaging velocity. The project was completed prior to the 2026 monsoon season and cost approximately $6000. With the subsequent good monsoon, the dip was observed flowing several times. As many as 700,000 gallons of water annually will be diverted to the Borrow Pit, replenishing the wetland and recharging groundwater.
NEXT STEPS
The Nature Center will keep working with the local landowner and the community to implement our restoration plans for the river and its floodplain. The two remaining years of the DFFM Invasive Plant Grant are expected to be sufficient for effective control of tamarisk in the Borrow Pit. We intend to continue to advance elements of the Borrow Pit restoration, including development of a detailed wetland restoration engineering design based on the groundwater level and effluent flow monitoring data. We also intend to pursue additional stormwater management improvements to increase the amount of water entering the Borrow Pit. The wetland restoration project is expected to cost around $500,000 to implement over a five-year period, so we are seeking additional grants and donations to support the effort. We will continue to work with the Santa Cruz River Coalition to preserve the river corridor as a wildlife refuge.