Infrastructures as colonial beachheads: The Central Arizona Project and the taking of Navajo resources

Colonial difference is a story of national infrastructures. To understand how colonialism works across Indigenous lands, we need to appreciate the physical, legal, and political factors involved in the building and expanding of national infrastructures in different historical contexts; infrastructures that arrive in some places while denied in others. Using archival documents, this article accounts for the colonial politics necessary to bring Colorado River water into Phoenix and Tucson. It highlights how the following moments worked to enlarge Arizona’s population and power while denying Diné water claims: the 1922 Colorado Compact, Arizona’s 1960s campaign for the Central Arizona Project, and recent Indian water settlements between Arizona and Navajo Nation. The infrastructures that emerged from these events formed a coal–energy–water nexus reliant on Navajo coal while constructing Arizona’s water network. In sum, these projects served as colonial beachheads—temporal encroachments on Indigenous lands and livelihoods that augment material and political difference over time and exacerbate inequalities.

Groundwater Recharge for Water Security

The Arizona Water Banking Authority (AWBA) was established in 1996 to make full use of Arizona’s Colorado River entitlement. It aims to address groundwater depletion in central Arizona and to protect Colorado River water users against future shortages due to interannual variability in water availability. Each year, the AWBA pays the costs to deliver any of the state’s unused entitlement to Colorado River water into central and southern Arizona and to store that water underground. The AWBA stores water on behalf of Central Arizona Project municipal subcontractors, other mainstream municipal Colorado River water rights holders, and tribal entities. Through its interstate banking agreements, the AWBA can also store water on behalf of the states of Nevada and California. Water stored by the AWBA is accounted for using Arizona’s statutorily created system of long-term storage credits (LTSCs), which allow future pumping of stored water within the same hydrologic basin. During shortage conditions in the Lower Basin of the Colorado River, the AWBA will distribute the LTSCs, enabling recipients to pump groundwater that otherwise would not be permitted. In this way, the AWBA serves as a unique insurance mechanism against shortages for users of Colorado River water in Arizona and the Lower Basin. To date, the AWBA’s focus has been on storage, yet in the coming years, its activities will shift to recovery, and it will need to confront additional challenges associated with matching supplies with demands and limitations on water available for recharge.

Reimagining the Colorado River by Exploring Extreme Events

Workshops exploring environmental, social, and political scenarios to prepare for negotiating new Colorado River water management guidelines took on added realism when the COVID-19 pandemic started.

Feasibility of Multi-Year Forecast for the Colorado River Water Supply: Time Series Modeling

The future of the Colorado River water supply (WS) affects millions of people and the US economy. A recent study suggested a cross-basin correlation between the Colorado River and its neighboring Great Salt Lake (GSL). Following that study, the feasibility of using the previously developed multi-year prediction of the GSL water level to forecast the Colorado River WS was tested. Time-series models were developed to predict the changes in WS out to 10 years. Regressive methods and the GSL water level data were used for the depiction of decadal variability of the Colorado River WS. Various time-series models suggest a decline in the 10-year averaged WS since 2013 before starting to increase around 2020. Comparison between this WS prediction and the WS projection published in a 2012 government report (derived from climate models) reveals a widened imbalance between supply and demand by 2020, a tendency that is confirmed by updated WS observation. Such information could aid in management decision-making in the face of near-future water shortages.

Evaluation of Groundwater Sources, Flow Paths, and Residence Time of the Gran Desierto Pozos, Sonora, Mexico

Environmental isotopes and water chemistry distinguish water types, aquifer recharge mechanisms, and flow paths in the Gran Desierto and Colorado River delta aquifer. The aquifer beneath the Gran Desierto supports a series of spring-fed wetlands, locally known as pozos, which have provided vital water resources to diverse flora and fauna and to travelers who visited the area for millennia. Stable isotope data shows that local recharge originates as winter precipitation, but is not the main source of water in the pozos. Instead, Colorado River water with substantial evaporation is the main component of water in the aquifer that feeds the pozos. Before infiltration, Colorado River water was partially evaporated in an arid wetland environment. Groundwater followed flow paths, created by the Altar Fault, into the current location of the pozos at Bahía Adair. Mixing with seawater is observed at the pozos located near the coast of the Gulf of California. The wetlands or other natural settings that allowed recharge to the aquifer feeding the pozos no longer exist. This leaves the pozos vulnerable to major groundwater pumping and development in the area.

Feasibility of Multi-Year Forecast for the Colorado River Water Supply: Time Series Modeling

The future of the Colorado River water supply (WS) affects millions of people and the U.S. economy. A recent study suggested a cross-basin correlation between the Colorado River and its neighboring Great Salt Lake (GSL). Following that study, the feasibility of using the previously developed multi-year prediction of the GSL water level to forecast the Colorado River WS was tested. Time-series models were developed to predict the changes in WS out to 10 years. Regressive methods and the GSL water level data were used for the depiction of decadal variability of the Colorado River WS. Various time-series models suggest a decline in the 10-year-averaged WS since 2013 before starting to increase around 2020. Comparison between this WS prediction and the WS projection published in a 2012 government report (derived from climate models) reveals a widened imbalance between supply and demand by 2020. Further research to update similar multi-year prediction of the Colorado River WS is needed. Such information could aid in management decision making in the face of future water shortages.

Lax science can have negative impacts on conservation: A rebuttal to Lau and Jacobs (2017)

A recent paper by Lau and Jacobs (2017, PeerJ) negatively contributes to a critical conservation problem in the Gulf of California—better regulation of fisheries in the Upper Gulf of California. The paper’s broader conclusions are not supported by the data presented, and numerous assumptions and claims regarding previous work are misstated or incorrect, including claims of sister-group relationship between Colpichthys hubbsi and C. regis and an implied sister group relationship between Uca monilifera and Uca princeps, claims regarding Colorado River water flow to the Gulf of California, and claims of post-dam “significantly different adaptive regimes on taxa in the [Upper Gulf].”

Lax science can have negative impacts on conservation: A rebuttal to Lau and Jacobs (2017)

A recent paper by Lau and Jacobs (2017, PeerJ) negatively contributes to a critical conservation problem in the Gulf of California—better regulation of fisheries in the Upper Gulf of California. The paper’s broader conclusions are not supported by the data presented, and numerous assumptions and claims regarding previous work are misstated or incorrect, including claims of sister-group relationship between Colpichthys hubbsi and C. regis and an implied sister group relationship between Uca monilifera and Uca princeps, claims regarding Colorado River water flow to the Gulf of California, and claims of post-dam “significantly different adaptive regimes on taxa in the [Upper Gulf].”