More Like this

1. Redefining the age of the lower Colorado River, southwestern United States

   https://doi.org/10.1130/G48080.1  

   Crow, R.S.; Schwing, J.; Karlstrom, K.E.; Heizler, M.; Pearthree, P.A.; House, P.K.; Dulin, S.; Jänecke, S.U.; Stelten, M.; Crossey, L.J. (February 2021, Geology)

   null (Ed.)

   Abstract Sanidine dating and magnetostratigraphy constrain the timing of integration of the lower Colorado River (southwestern United States and northern Mexico) with the evolving Gulf of California. The Colorado River arrived at Cottonwood Valley (Nevada and Arizona) after 5.24 Ma (during or after the Thvera subchron). The river reached the proto–Gulf of California once between 4.80 and 4.63 Ma (during the C3n.2r subchron), not at 5.3 Ma and 5.0 Ma as previously proposed. Duplication of section across newly identified strands of the Earthquake Valley fault zone (California) probably explains the discrepancy. The data also imply the start of focused plate motion and basin development in the Salton Trough (California) at 6–6.5 Ma and relative tectonic stability of the southernmost part of the lower Colorado River corridor after its integration. After integration, the Colorado River quickly incised through sediment-filled basins and divides between them as it also likely excavated Grand Canyon (Arizona). The liberated sediment from throughout the system led to deposition of hundreds of meters of Bullhead Alluvium downstream of Grand Canyon after 4.6 Ma as the river adjusted to its lower base level. 

   more » « less
2. Simulating Groundwater‐Streamflow Connections in the Upper Colorado River Basin

   https://doi.org/10.1111/gwat.13000  

   Tran, Hoang; Zhang, Jun; Cohard, Jean‐Martial; Condon, Laura E.; Maxwell, Reed M. (May 2020, Groundwater)
3. Institutional analysis of water governance in the Colorado River Basin, 1922–2022

   https://doi.org/10.3389/frwa.2024.1451854  

   Lawless, Krista L; Garcia, Margaret; White, Dave D (November 2024, Frontiers in Water)

   The 1922 Colorado River Compact started the long history of water governance in the Colorado River Basin. Over the last century, the institutional structure has shaped water governance in the basin. However, an understanding of the long-term evolution is lacking. This study examines how water management strategies have evolved at the basin scale by incorporating institutional, temporal, and network structure analysis methods to examine long-term changes. Content analysis was employed to systematically investigate encouraged and/or discouraged water management actions at different rule levels. The water governance network was examined at four points in time to map the institutional structure, actors, and governance level at which rules are issued and targeted. Using institutional analysis, we found constitutional, operational, and collective-choice level rules for water supply, storage, movement, and use have been altered via layering of new governance rules without major rule or responsibility alteration. The network analysis results indicate that key decision-making positions have remained and actors who issue and are targeted by the rules lack significant change. We found original positions of power have been maintained, potentially stagnating the space for problem-solving and management strategy renegotiation. Our results indicate that path dependency has shaped water governance and who is able to influence decision-making. 

   more » « less
4. River corridor beads are important areas of floodplain‐groundwater exchange within the Colorado River headwaters watershed

   https://doi.org/10.1002/hyp.15282  

   Schulz, Evan_Y; Morrison, Ryan_R; Bailey, Ryan_T; Raffae, Muhammad; Arnold, Jeffrey_G; White, Michael_J (September 2024, Hydrological Processes)

   Abstract Floodplains are essential ecosystems that provide a variety of economic, hydrologic, and ecologic services. Within floodplains, surface water‐groundwater exchange plays an important role in facilitating biogeochemical processes and can have a strong influence on stream hydrology through infiltration or discharge of water. These functions can be difficult to assess due to the heterogeneity of floodplains and monitoring constraints, so numerical models are useful tools to estimate fluxes, especially at large spatial extents. In this study, we use the SWAT+ (Soil and Water Assessment Tool) ecohydrological model to quantify magnitudes and spatiotemporal patterns of floodplain surface water‐groundwater exchange in a mountainous watershed using an updated version of thegwflowmodule that directly calculates floodplain‐aquifer exchange rates during periods of floodplain inundation. Thegwflowmodule is a spatially distributed groundwater modelling subroutine within the SWAT+ code that uses a gridded network and physically based equations to predict groundwater storage, groundwater head, and groundwater fluxes. We used SWAT+ to model the 7516 km²Colorado River headwaters watershed and streamflow data from USGS gages for calibration and testing. Models that included floodplain‐groundwater interactions outperformed those without such interactions and provided valuable information about floodplain exchange rates and volumes. Our analyses on the location of floodplain fluxes in the watershed also show that wider areas of floodplains, “beads” (e.g., like beads on a necklace), exchanged a higher net and per area volume of water, as well as higher rates of exchange, compared to narrower areas, “strings.” Study results show that floodplain channel‐groundwater exchange is a valuable process to include in hydrologic models, and model outputs could inform land conservation practises by indicating priority locations, such as beads, where substantial hydrologic exchange occurs. 

   more » « less
5. Understanding the temporal variability and predictability of streamflow signatures in the Colorado River Basin

   https://doi.org/10.1016/j.jhydrol.2024.132386  

   Puente, Patricia; Rajagopalan, Balaji; Condon, Laura E (February 2025, Journal of Hydrology)