The University of Arizona (UA) Water Resources Research Center (WRRC) will be hiring two post-doctoral research associates into 24-month positions beginning in early 2022. These opportunities both provide a foundation for building a research portfolio and contributing to greater awareness and understanding of water resources in Arizona and the West. Both positions require that the candidate hold a PhD in a field with relevance to the position description at the time of hiring.
Summary of Isotope Research on Sources of Perennial Flow in the San Pedro River
Some major points of the study are:
- The reaches of the San Pedro River that have perennial (year-round) surface water are critical to the existing rich riparian ecosystem. Management of the river basin with the best interests of the ecosystem in mind requires an understanding of the sources of the perennial water. Five reaches with perennial water between the international border and Redington were studied (see map).
- Measurements of stable oxygen and hydrogen isotopes enable us to distinguish three sources: (a) water flowing from upstream in or just beneath the river channel; (b) summer monsoon floodwater stored in the bed and banks of the river; and (c) water from the mountainous flanks of the valley.
- Perennial flow in the reach south of Sierra Vista (Area 1) is a combination of sources (a) and (c).
- All three sources contribute to the perennial reach near St. David (Area 2), where the source (c) is deep basin groundwater.
- In Cascabel, near Benson Narrows (Area 3), source (c) predominates. The water is probably from Red Rock Creek.
- At Cascabel, near Gamez Road (Area 4), sources (a) and (c) supplied surface flow that had disappeared by 2019. Source (c) was from Hot Springs Canyon.
- Perennial flow near Bingham Cienega at Redington (Area 5) prior to the early 2000s was of source (c) and appears to have flowed to the river through a limestone aquifer that has been quickly depleted under drought conditions.
- Impermeable sills of rock in the riverbed divide the valley into four separate groundwater basins that are becoming increasingly isolated from each other as perennial flow volumes decrease. Decrease in flow has occurred because of long-term drought in combination with pumping of groundwater.
- Increased urban growth upstream of Benson is likely to degrade the perennial reaches near Sierra Vista and St. David.
On Wednesday, November 10, the WRRC hosted a Brown Bag webinar featuring presentations by student researchers who received funding in 2020 through the WRRC from the Water Resources Research Act, Section 104(b) grant program.
Did you know that the WRRC was part of the bipartisan infrastructure bill? The Infrastructure Investment and Jobs Act, signed into law this week, contains historic investment in water resources and, of particular importance to the WRRC
The American Water Resources Association (AWRA) Annual Water Resources Conference was held virtually this week, November 8-10, 2021. On the first day of the conference, WRRC Director Sharon B. Megdal and Graduate Student Assistant Simone A. Williams presented at two separate sessions on different WRRC efforts.