California Water Myths

Presents eight common myths about water supply, ecosystems, and the legal and political aspects of governing California's water system and explains how each myth drives the debate, the reality, and alternatives for better informed policy discussions

Effect of baselevel change on floodplain and fan sediment storage and ephemeral tributary channel morphology, Navarro River, California

Managed baselevel lowering in tributaries that emerge from small canyons onto forested floodplains affects floodplain and fan sediment storage and small ephemeral tributary channel morphology in the Navarro River basin, Mendocino Country, California, USA. Numerous small tributaries (drainage areas up to several square kilometres) flow through culverts under Highway 128 across the forested floodplain of the Navarro River and one of its major tributaries, the North Fork. Excavation significantly deepened and widened these small tributaries upstream and downstream of culverts under the highway following the 1997 flood (recurrence interval 12 years), that inundated both the floodplain and the highway and culvert system. The excavation lowered the local baselevel of the tributary systems within the floodplain. This field study documents the effect of the lowered baselevel on floodplain and fan sediment storage and ephemeral tributary channel morphology. Excavation created defined channels in the floodplain where no channels previously existed. Additionally, the excavation and baselevel change created steps, or knickpoints, that migrated headward and incised the upstream tributary channels. Tributary incision decreases the sediment storage potential of the fan and floodplain and reduces the residence time for storage of fine sediment. A reduction in fine sediment residence time degrades downstream habitat for anadromous fish and other aquatic organisms in the Navarro River. Large wood influences floodplain and small tributary channel morphology by forming steps and increases sediment residence time by trapping sediment in forested tributary-fan-floodplain systems. Although this field investigation is specific to the Navarro River basin, our findings linking culvert maintenance excavation to geomorphic processes may be extended to other roads on forested floodplains in the Pacific Northwest or other systems with roads on floodplains

UNT Libraries 30-Second Survey

This report documents the UNT Libraries 30-Second Survey project funded through the Dean's Innovation Grant funded by the UNT Libraries. The final report briefly describes the UNT Libraries 30-Second Survey project activities, budget, outcomes, best practices, and sustainability

Hydrologic Response and Watershed Sensitivity to Climate Warming in California's Sierra Nevada

This study focuses on the differential hydrologic response of individual watersheds to climate warming within the Sierra Nevada mountain region of California. We describe climate warming models for 15 west-slope Sierra Nevada watersheds in California under unimpaired conditions using WEAP21, a weekly one-dimensional rainfall-runoff model. Incremental climate warming alternatives increase air temperature uniformly by 2°, 4°, and 6°C, but leave other climatic variables unchanged from observed values. Results are analyzed for changes in mean annual flow, peak runoff timing, and duration of low flow conditions to highlight which watersheds are most resilient to climate warming within a region, and how individual watersheds may be affected by changes to runoff quantity and timing. Results are compared with current water resources development and ecosystem services in each watershed to gain insight into how regional climate warming may affect water supply, hydropower generation, and montane ecosystems. Overall, watersheds in the northern Sierra Nevada are most vulnerable to decreased mean annual flow, southern-central watersheds are most susceptible to runoff timing changes, and the central portion of the range is most affected by longer periods with low flow conditions. Modeling results suggest the American and Mokelumne Rivers are most vulnerable to all three metrics, and the Kern River is the most resilient, in part from the high elevations of the watershed. Our research seeks to bridge information gaps between climate change modeling and regional management planning, helping to incorporate climate change into the development of regional adaptation strategies for Sierra Nevada watersheds

Comparing Futures for the Sacramento-San Joaquin Delta

Analyzes expected changes to the hub of California's water system and presents a comparative assessment of four water management strategies for environmental sustainability and water supply reliability. Discusses policy and regulatory implications

Storing Water for the Environment: Operating Reservoirs to Improve California’s Freshwater Ecosystems

California’s freshwater ecosystems—its lakes, rivers, floodplains, meadows, natural and managed wetlands, and estuaries—are a vital part of the state’s natural infrastructure. These ecosystems provide numerous benefits, including water supply, hydropower, flood control, fisheries, recreation, and cultural and aesthetic value. They are also home to the nation’s most diverse array of plant and animal communities, with numerous freshwater species found only in California (Jensen et al. 1993; Grantham et al. 2017)

Managing Water Stored for the Environment During Drought

Storing water in reservoirs is important for maintaining freshwater ecosystem health and protecting native species. Stored water also is essential for adapting to the changing climate, especially warming and drought intensification. Yet, reservoir operators often treat environmental objectives as a constraint, rather than as a priority akin to water deliveries for cities and farms. Reservoir management becomes especially challenging during severe droughts when surface water supplies are scarce, and urban and agricultural demands conflict with water supplies needed to maintain healthy waterways and wetlands. In times of drought, most freshwater ecosystems suffer. This blog post examines 2021 water year actions by the federal Central Valley Project (CVP) and the State Water Project (SWP), which sought to maximize water deliveries while meeting environmental regulatory standards in a severe drought. Based on this experience, we offer recommendations to better protect the environment if California is faced with dry conditions in 2022 or beyond