Resources

Hydrogeomorphic typing of Van Norden Meadow, conducted by Dave Weixelman, Rachel Hutchinson, Sarah Yarnell, and Ryan Peek

In 2010, the USDA Forest Service Pacific Southwest Region (USFS PSW) received a grant from the National Fish and Wildlife Foundation, with matching funds from the State Department of Water Resources, to conduct an assessment of potential water resource benefits of meadow restoration on the 10 national forests distributed across much of the Sierra Nevada. Subsequently, USFS PSW contracted with the Viers Laboratory in the Information Center for the Environment at UC Davis to conduct a field verification of two important objectives of the overall project, described below. This final project report describes the methodology and results of the combined field campaigns (2010-2012). Our efforts were embedded within a broad-scale regional assessment of meadows managed by the Forest Service.

The Center for Watershed Sciences authored a technical report, "Montane Meadows in the Sierra Nevada: Changing Hydroclimatic Conditions and Concepts for Vulnerability Assessment" to better prepare the meadows community for ecosystem monitoring and restoration planning under future hydroclimatic conditions.

Natural Range of Variation (NRV) assessments (essentially equivalent to Historical Range of Variation [HRV] assessments) provide baseline information on ecosystem conditions (composition, structure, and function) that can be compared to current conditions to develop an idea of trend over time and an idea of the level of departure of altered ecosystems from their “natural” state (Morgan et al. 1984, Manley et al. 1995, Landres et al. 1999, Wiens et al. 2012; see Methods). These trend assessments form part of the basis for the assessment of ecological integrity that is required in the 2012 Forest Service Planning Rule. NRV assessments were carried out for 11 terrestrial ecosystems by the Pacific Southwest Region Ecology Program between October, 2012 and May, 2013, using historical information (primarily from the pre-Euroamerican period, 16th century to the mid-19th century) as well as information from modern-day reference ecosystems and other sources.

In this project, we sought to identify putative climate change refugia and connectivity between meadows across the Sierra Nevada and to use data on persistence, stability, and genetic diversity of mammal populations to validate these hypotheses. We addressed California Landscape Conservation Cooperative priorities of scale by analyzing across the Sierra Nevada. We involved state and federal natural resource managers throughout the project; some are already beginning to incorporate results. Our products focused on maps and tools that are user-friendly and that allow managers to make decisions and set landscape conservation priorities. We are communicating project outcomes directly to CA LCC partners to aid in decisions from immediate, small-scale adaptation projects to region-wide changes in use, development, and planning for state and federal land management.

Grazing photo examples by the Central Sierra Environmental Resource Center (CSERC), 2013

Relating watershed structure to streamflow generation is a primary focus of hydrology. However, comparisons of longitudinal variability in stream discharge with adjacent valley structure have been rare, resulting in poor understanding of the distribution of the hydrologic mechanisms that cause variability in streamflow generation along valleys. This study explores detailed surveys of stream base flow across a gauged, 23 km2 mountain watershed. Research objectives were (1) to relate spatial variability in base flow to fundamental elements of watershed structure, primarily topographic contributing area, and (2) to assess temporal changes in the spatial patterns of those relationships during a seasonal base flow recession.

Overbank flood recharge is increasingly acknowledged as important for estimations of aquifer sustainable yield. The physics of this process in areas with shallow groundwater, however, is not well understood and typically is not included in river or groundwater models. Modeling of the overbank flood recharge process was undertaken using a fully coupled, surface-subsurface flow model to compare the volume of infiltration through a floodplain with varying surface sediment, aquifer, and flood parameters. The infiltration volume was found to increase with the conductance of the clogging layer (represented by a thin veneer of sediments across the floodplain and river bed), flood wave height, peak duration, and aquifer transmissivity and to decrease with increasing water table gradient (positive toward the river). The influence of the flood wave and aquifer hydraulic parameters was more pronounced in systems with sand or loam clogging layers.

Understanding streamflow generation using natural tracers in semi-arid, seasonally snow-covered mountain streams is essential for water resources management, water quality study and evaluation of impacts from climate change. This study reports temporal variations in stable isotopic ratios and concentrations of major dissolved ions of streamwater and precipitation between October, 2005 and May, 2007 in Red Canyon Creek and its tributary, Cherry Creek, draining carbonate-rich catchments on the southeastern flank of Wind River Range (Wyoming, USA). Although the isotopic ratios of oxygen and hydrogen in precipitation increased from approximately −33‰ to −13‰ and −260‰ to −110‰, respectively, during winters of 2006 and 2007, the oxygen and hydrogen isotopic compositions of streamwater at all sites remained unchanged throughout the year at −18.6 ± 0.3‰ (n = 88) and −142 ± 1.6‰ (n = 40) for δ18O and δ2H, respectively.

Articulates methods for monitoring hydrologic and water quality impacts of meadow restoration in the Sierra Nevada. This includes recommended analyses and standard metrics that, if reported, will enable future regional studies to combine data across meadow restoration projects. These methods are not exhaustive, rather we identify the key indicators that should be monitored by all projects aiming to alter hydrology or water quality through meadow restoration. Data collected are grouped into five categories based on the objectives they support: 1) groundwater elevation; 2) stream flow; 3) water temperature; 4) sedimentation; and 5) overview data, such as photographs and maps that support multiple monitoring objectives. Table 1 summarizes which data are collected and how they are reported. Tables and figures from the text are referenced as examples of how data are reported.