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California Water Plan 2013: Mountain Counties Regional Report
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California Water Plan 2013: Mountain Counties Regional Report
California Department of Water Resources (DWR) | October 30, 2014...
Summary
As the State works to solve the water crisis in California, the potential for redirected impacts in the Mountain Counties Area is acute....
As the State works to solve the water crisis in California, the potential for redirected impacts in the Mountain Counties Area is acute. It is critical that the State recognize the significance and importance of the Sierra Nevada mountain range to the local communities, the environment, the Delta, and all of California, now and for future generations.

Water resource managers are working with elected officials, governmental agencies, businesses, farmers and conservationists on innovative programs for watershed management, water use efficiency, conservation, reuse, and recycling. Water managers and others in the region are actively balancing the water supplies that support both a vibrant economy and a healthy environment. They are also continually improving the management of surface and groundwater sources to sustain this important balance for this region and California.

Statewide Significance

Water is the number one resource exported from the Sierra Nevada, and the 16-county Mountain Counties Area is the primary source for most of that exported water. The Mountain Counties Area is over 15,700 square miles and represents 9.9 percent of the state. More than 40 percent of California’s developed water supply originates in the Mountain Counties area serving end users throughout the state.

-The reservoirs in the region produce hydroelectricity to supply homes and businesses in the western United States. Mountain Counties has more hydroelectric generation facilities than any other region in California.

- Agriculture in this region feeds the state and the world and is an economic driver for California’s economy.

Recreation and tourism in the Sierra Nevada mountains help communities thrive economically as guests come from all over the world to hike, ski, fish, raft, and boat.
- Water stored behind designated reservoirs in the ten major watershed areas have dedicated in-stream flow releases designed to meet the many beneficial uses for the environment, agriculture, and urban users and provides storage to reduce the magnitude of flood flows.
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California’s Water: Protecting Headwaters
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California’s Water: Protecting Headwaters
Public Policy Institute of California (PPIC) | October 1, 2016...
Summary
Mountainous regions provide most of the state’s water supply. But major problems loom— from a growing risk of wildfires to a shrinking snowpack....

Mountainous regions provide most of the state’s water supply. But major problems loom— from a growing risk of wildfires to a shrinking snowpack. This brief outlines ways California and the federal government—the largest landowner in headwater areas—could address critical problems in these areas.

This publication is part of a briefing kit that summarizes a dozen of the state’s most pressing water management issues.

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Climate and landscape drive the pace and pattern of conifer encroachment into subalpine meadows

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Climate and landscape drive the pace and pattern of conifer encroachment into subalpine meadows
Ecological Applications, Ecological Society of America | May 8, 2018...
Summary
Mountain meadows have high biodiversity and help regulate stream water release following the snowmelt pulse. However, many meadows are experiencing woody plant encroachment,...

Mountain meadows have high biodiversity and help regulate stream water release following the snowmelt pulse. However, many meadows are experiencing woody plant encroachment, threatening these ecosystem services. While there have been field surveys of individual meadows and remote sensing‐based landscape‐scale studies of encroachment, what is missing is a broad‐scale, ground‐based study to understand common regional drivers, especially at high elevations, where land management has often played a less direct role. With this study, we ask: What are the climate and landscape conditions conducive to woody plant encroachment at the landscape scale, and how has historical climate variation affected tree recruitment in subalpine meadows over time? We measured density of encroaching trees across 340 subalpine meadows in the central Sierra Nevada, California, USA, and used generalized additive models (GAMs) to determine the relationship between landscape‐scale patterns of encroachment and meadow environmental properties. We determined ages of trees in 30 survey meadows, used observed climate and GAMs to model the relationship between timing of recruitment and climate since the early 1900s, and extrapolated recruitment patterns into the future using downscaled climate scenarios. Encroachment was high among meadows with lodgepole pine (Pinus contorta Douglas ex Loudon var. murrayana (Balf.) Engelm.) in the immediate vicinity, at lower elevations, with physical conditions favoring strong soil drying, and with maximum temperatures above or below average. Climatic conditions during the year of germination were unimportant, with tree recruitment instead depending on a 3‐yr seed production period prior to germination and a 6‐yr seedling establishment period following germination. Recruitment was high when the seed production period had high snowpack, and when the seedling establishment period had warm summer maximum temperatures, high summer precipitation, and high snowpack. Applying our temporal model to downscaled output from four global climate models indicated that the average meadow will shift to forest by the end of the 21st century. Sierra Nevada meadow encroachment by conifers is ubiquitous and associated with climate conditions increasingly favorable for tree recruitment, which will lead to substantial changes in subalpine meadows and the ecosystem services they provide.

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Cumulative effects of fire and drought in Mediterranean ecosystems

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Cumulative effects of fire and drought in Mediterranean ecosystems
Ecosphere, Ecological Society of America (ESA) | August 18, 2017...
Summary
The occurrence of multiple disturbances can jointly affect the recovery capacity of ecosystems, potentially leading to changes in vegetation dynamics or loss of resilience....
The occurrence of multiple disturbances can jointly affect the recovery capacity of ecosystems, potentially leading to changes in vegetation dynamics or loss of resilience. The effects of interacting disturbances on ecosystems are, however, not well understood. We use a model system based on Mediterranean-type ecosystems (MTEs) to examine how the interplay between vegetation regeneration traits andcompound, stochastic disturbances modulate ecosystem dynamics. We developed a state-and-transition simulation model including two tree species with contrasting regeneration strategies (seeder vs. resprouter) and a shrub-land formation. We aim to assess potential compositional switches under contrasted scenarios of compound fire–drought regimes, and to characterize the cumulative effects of fire–drought(synergism vs. antagonism) relative to the effects of individual disturbance regimes. Our simulation results indicate that interaction between moderate fire and sporadic drought recurrence—as opposed to chronic dryness—can act as a strong mechanism generating highly heterogeneous landscapes in which different regeneration types coexist, as observed in MTEs. Resprouters dominated under individual, moderate disturbance regimes of fire or drought, whereas the interaction of the two disturbances promoted the long-term coexistence of both tree regeneration strategies. However, shrub-land expansion and persistence at the expanse of forests was favored by increases in drought recurrence and associated fire–drought interactions, highlighting the potential for important vegetation changes in MTEs under climate change. Overall, the cumulative effects of fire and drought can lead to distinct landscape configurations under moderate disturbance regimes that are otherwise only attained under high frequency of individual disturbances. At the ecosystem level, however, we suggest that disturbance-induced vegetation dynamics can modify vegetation sensitivity and resilience to further disturbances precluding the prevalence of synergistic effects of the two disturbances.

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Estimating evapotranspiration change due to forest treatment and fire at the basin scale in the Sierra Nevada, California: Forest Disturbance and Evapotranspiration Change

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Estimating evapotranspiration change due to forest treatment and fire at the basin scale in the Sierra Nevada, California: Forest Disturbance and Evapotranspiration Change
Ecohydrology | April 6, 2018...
Summary
We investigated the potential magnitude and duration of forest evapotranspiration (ET) decreases resulting from forest‐thinning treatments and wildfire in west‐slope watersheds of the...
We investigated the potential magnitude and duration of forest evapotranspiration (ET) decreases resulting from forest‐thinning treatments and wildfire in west‐slope watersheds of the Sierra Nevada range in California, USA, using a robust empirical relation between Landsat‐derived mean‐annual normalized difference vegetation index (NDVI) and ET measured at flux towers. Among forest treatments, the minimum observed NDVI change required to produce a significant departure from control plots with NDVI of about 0.70 was −0.09 units, corresponding to a basal‐area reduction of 29.1 m²/ha (45% reduction) and equivalent to an estimated ET reduction of 153 mm/year (21% change; approximate mean annual precipitation = 1,000 mm). Intensive thinning in highly productive forests that approached prefire‐exclusion densities reduced basal area by 40–50%, generating estimated ET reductions of 153–218 mm/year (21–27% change) over 5 years following treatment. Low‐intensity underburn treatments resulted in no significant change in ET. Examining the cumulative impact of wildfires on ET between 1990 and 2008, we found that the lower and wetter American River basin (5,310 km²) generated more than twice the ET reduction per unit area than those in the higher and drier Kings River basin (4,790 km²), corresponding to greater water and energy limitations in the latter and greater fire severity in the former. A rough extrapolation of these results to the entire American River watershed suggests that ET reductions due to forest thinning by wildfire could approach 10% of full natural flows for dry years and 5% over all years.

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Forest Management (Resource Management Strategy)
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Forest Management (Resource Management Strategy)
California Department of Water Resources (DWR) | July 29, 2016...
Summary
Forest lands in California, the majority of which are in the middle to high elevation foothills and mountains, produce a diverse array of...
Forest lands in California, the majority of which are in the middle to high elevation foothills and mountains, produce a diverse array of resources such as water, timber, native vegetation, fish, wildlife, and livestock, and outdoor recreation. However, the water produced by these forests has economic value that equals or exceeds that of any other forest resource (Krieger 2001; California Department of Forestry and Fire Protection 2003).

Most of California’s major rivers and a substantial portion of its runoff originate in these forests; therefore, most of California’s major water development projects are tied strongly to forested watersheds.

Forest management activities can affect water quantity and quality. This strategy focuses on forest management activities, on both public and privately-owned forest lands, whose goals specifically include improvement of the availability and quality of water for downstream users.

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Gone. Decades of greed, neglect, corruption, and bad politics led to last year’s Paradise fire, the worst in California history. It should never have happened. It will happen again.

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Gone. Decades of greed, neglect, corruption, and bad politics led to last year’s Paradise fire, the worst in California history. It should never have happened. It will happen again.
California Sunday Magazine | July 31, 2019...
Summary
By the time I made it to Paradise, the deadliest wildfire in California history was four months past, and the burned-out ridge between the...
By the time I made it to Paradise, the deadliest wildfire in California history was four months past, and the burned-out ridge between the two river canyons was pouring rain. I was riding the Skyway, the road from Chico to Paradise, flatland to hilltop, trying to understand what forces had conspired last November to create a blaze of such anger that it took the lives of 85 people and destroyed 19,000 structures.

I had puzzled out enough disasters to know that tragedy was a force of intricate construction. It wasn’t one detached act that materialized as tragedy but myriad smaller acts — some incidental, some accidental, others malevolent — that lined up in perfect continuity. Had one circumstance in the sequence lost its footing, a cosmic stumble, the next circumstance would have never hitched on, and tragedy would have been averted.

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Hydroclimate Variability in Snow-fed River Systems

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Hydroclimate Variability in Snow-fed River Systems
American Meteorological Society (AMS) | June 25, 2019...
Summary
Snow-fed river system communities are highly sensitive to climate change because the majority of their water supply is derived from snow. A warmer...

Snow-fed river system communities are highly sensitive to climate change because the majority of their water supply is derived from snow. A warmer climate shifts precipitation phase from snow to rain, altering snowpack dynamics, shifting peak streamflow timing, reducing groundwater recharge, and increasing winter and spring flooding. Warmer spring and summer temperatures further compound these “snow droughts” by increasing evapotranspiration rates and irrigation water demand. This presents critical challenges in managing seasonal water supply and demand engineered for stationary climate patterns.

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Improving the Health of California’s Headwater Forests
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Improving the Health of California’s Headwater Forests
Public Policy Institute of California (PPIC) | September 18, 2017...
Summary
California’s headwater forests are not thriving under current management practices, and changes are needed to make them more resilient to periodic drought and...
California’s headwater forests are not thriving under current management practices, and changes are needed to make them more resilient to periodic drought and long-term climate change. More active management of these lands is needed to improve forest health, reduce the risk of major wildfires and pest infestations, and maintain the flow of benefits provided by this critical natural infrastructure.

Decades of fire suppression, an emphasis on short-term management priorities, weather extremes, and a warming climate have set the stage for the decline in forest resilience. Two-thirds of the state’s surface water supply originates in these mountainous forests. California stands to lose timber production, wildlife habitat, recreational opportunities, and water supply if this vital natural infrastructure continues to decline. Management options exist—prescribed fire, managed wildfire, mechanical thinning, and forest pest treatments—that can help rebuild resilience in these forests and prepare them for a challenging future.

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Incorporating anthropogenic influences into fire probability models: Effects of human activity and climate change on fire activity in California

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Incorporating anthropogenic influences into fire probability models: Effects of human activity and climate change on fire activity in California
PLoS ONE | April 28, 2016...
Summary
The costly interactions between humans and wildfires throughout California demonstrate the need to understand the relationships between them, especially in the face of...

The costly interactions between humans and wildfires throughout California demonstrate the need to understand the relationships between them, especially in the face of a changing climate and expanding human communities. Although a number of statistical and process-based wildfire models exist for California, there is enormous uncertainty about the location and number of future fires, with previously published estimates of increases ranging from nine to fifty-three percent by the end of the century. Our goal is to assess the role of climate and anthropogenic influences on the state’s fire regimes from 1975 to 2050. We develop an empirical model that integrates estimates of biophysical indicators relevant to plant communities and anthropogenic influences at each forecast time step. Historically, we find that anthropogenic influences account for up to fifty percent of explanatory power in the model. We also find that the total area burned is likely to increase, with burned area expected to increase by 2.2 and 5.0 percent by 2050 under climatic bookends (PCM and GFDL climate models, respectively). Our two climate models show considerable agreement, but due to potential shifts in rainfall patterns, substantial uncertainty remains for the semiarid inland deserts and coastal areas of the south. Given the strength of human-related variables in some regions, however, it is clear that comprehensive projections of future fire activity should include both anthropogenic and biophysical influences. Previous findings of substantially increased numbers of fires and burned area for California may be tied to omitted variable bias from the exclusion of human influences. The omission of anthropogenic variables in our model would overstate the importance of climatic ones by at least 24%. As such, the failure to include anthropogenic effects in many models likely overstates the response of wildfire to climatic change.

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