Healthy Watersheds California

Pacific Forest Trust is advancing a new approach to permanently safeguard our water supply by restoring California’s key source watersheds.

Water security and supplies are threatened in California and the West. Catastrophic fire, periods of extreme drought alternating with major floods, and a warming climate have created a dangerous landscape for the state’s precious water resources. Water restrictions and competing demands leading to legal battles are becoming common. Even maintaining existing supplies is made more challenging with climate change. Increasing water supplies by conventional means, such as new dams or desalination, is expensive, contentious, and undependable. We are developing a new approach to permanently safeguard our water and increase supplies by restoring and securing our primary source watersheds.

Analysis:

Protecting California’s Wildlife Heritage—Climate Smart Biodiversity Planning

The 7-million-acre Sacramento River Headwaters Region, and its surrounding 3-million- acre buffer zone, has an extraordinarily important role for biodiversity as well as water supply in California. Delineated by three mountain ranges (the northern Sierra, southern Cascade and Klamath-Trinity) it’s varied topography, soils and geology support an extraordinarily wide variety of plants and habitats. The region contains over 80% of California’s natural habitat types and hosts over 60% of its vertebrate species; in fact it is one of 33 globally recognised biodiversity “hot spots”. With such a major role in supporting California’s biodiversity, PFT led a study to see how it would fare under intensifying climate change.

Watch the presentation and read the final report

Securing our water at the source.

The vast majority of California’s drinking and irrigated agricultural water—as well as 85% of freshwater to San Francisco Bay—comes from the watersheds that feed the Shasta/Trinity and Oroville reservoirs. Without these watersheds, no amount of infrastructure can guarantee California’s water security. The current conditions and future function of these watersheds are compromised by increased fire, degradation, fragmentation, and development. Current conservation and restoration efforts lack the sustained investment and landscape approach necessary for an effective, lasting solution.

A partnership for water security.

To make significant gains in enduring water security, we need a strategic, integrated, comprehensive landscape approach to restore and protect these key source watersheds. Implementing this strategy in collaboration with both private and public landowners using the best science, restoration, and conservation techniques, we can keep forests intact and healthy and increase water supplies, while also decreasing catastrophic fire risk.

Our proposed approach:

California’s key watersheds provide clean drinking water for more than 28 million Californians and support the state as the nation’s leading agricultural producer. The economic value of this water far exceeds that of any other forest product.

State funds/finances comprehensive watershed restoration (e.g. forest thinning, road removal, wet meadow, and riparian improvement) and conservation to ensure watershed integrity (permanent working forest conservation agreements that maintain desired conditions on private lands).
Contracts for work on private lands are issued; bids for federal lands work are let.
State makes a 15-20 year commitment for strategy, funding, and implementation that results in 75-85% of watersheds restored and maintained in resilient condition.

Pictured above: California’s five key source watersheds, the Feather, Pit, McCloud, Upper Sacramento, and Upper Trinity, feed the Shasta and Oroville reservoirs, the core of the state’s utilized water supply. These watersheds span seven million acres and provide drinking water for over 28 million Californians, including the large majority of the water for the State Water Project.

Cooler and wetter than other landscapes, California’s key watersheds, if protected, can help climate-proof our water supplies.

Water security, naturally.

California’s key forested watersheds are the most abundant source of the state’s invaluable water supply, receiving the large majority of the state’s precipitation. This will continue and increase with climate change.

Research shows that forest restoration can increase water flows from watersheds by 5-20%, decrease flood risks by 25-40%, and extend cold water flows by 2-3 weeks into the hot summer months. Read more in our Risk Assessment.

While each watershed differs in its specific characteristics, overall, a more natural forest structure that mimics the region’s diverse, older, and more complex structure, with a mosaic of meadows, is key to restoring more natural water capture, storage, and release. Here are some of our recommended restoration actions and approaches:

Reduce Fire Risk & Increase Fire Resiliency: Decrease fire intensity by restoring more open, natural forest structure of larger, older trees that withstand fire.

Keep it Clean: Reduce sediment through increased low-harvest buffers and upslope tree retention.

Increase Snow-Water Yield: Restore a more open, complex canopy cover to allow snow to filter to shaded areas for longer retention, slower melt, and greater soil moisture.

Keep it Cool, Slow it Down: Restore and maintain canopy cover over streams to shade and cool water; large dead trees create eddies and pools to hold water longer.

Increase Total Precipitation: Manage harvests to develop old forest characteristics. Large, tall trees with uneven canopy capture more moisture, have lower transpiration demands, and allow deeper soil moisture.

Decrease Flooding: Reduce “rain-on-snow” events in cleared openings by retaining some tree cover and shading. Slowing snowmelt also provides well-metered water yields later into the year.

Increase Summer Release: Retain big, downed logs which hold moisture longer; thin dense forests of small tree stands, restore and maintain wet meadows, and keep snow and soil moisture longer with increased tall tree shade.

Keep Forests Continuous: Conserve forests and reduce fragmentation.

Good forest management helps secure our water supplies.

Clearcut forest: Snow melts quickly and gets little ground penetration. More “rain on snow” events lead to flooding and erosion.

Illustration of dense, unrestored forest

Dense, unrestored forest: Snow cannot penetrate to forest floor, which causes canopy melt with up to 70% evaporation, less snow pack, and less soil penetration.

Healthy forest cover: 8% deeper snow and a higher snow/water equivalent with reduced sediment. Snowmelt extends 3 times longer than in overly dense forests. Downed logs hold water and release it slowly, like a sponge.

Natural Systems = Essential Infrastructure

Water authorities across the country realize that natural water infrastructure is essential for a safe and secure water supply. Built infrastructure alone cannot solve our supply problems, and neglecting our watersheds is both dangerous and costly. Unmanaged or ill-managed forests set the stage for catastrophic wildfires that take lives, damage homes, and cost the state millions of dollars in suppression and recovery efforts. Encroaching development in watersheds causes erosion and reduces water quality. We can conserve and restore our forested watersheds for a fraction of the cost, in a fraction of the time it takes to build dams and filtration systems. It is time to invest in natural infrastructure to secure our water.

Example 1: New York City

Investing in natural infrastructure over filtration facilities saved New York City more than six billion dollars while preserving the myriad benefits of healthy ecosystems, such as biodiversity and carbon sequestration.

Example 2: Denver

After a catastrophic fire cost taxpayers $160 million, Denver Water decided to restore their key watersheds. A partnership with the U.S. Forest Service protects key watersheds at a cost of just $1.65 a year per household.

McCloud River: 570,000 acre-feet of pristine water a year

The McCloud Example

The McCloud River has the coldest, cleanest water in California, and is globally recognized for its fishery, biodiversity, and recreation. It hosts some of the most productive forestlands nationally, with sustainable forestry driving the local economy.

A key source watershed, the McCloud River basin provides 10% of the Sacramento River’s water supply. This work would create potential gains of ten to twenty percent additional water supplied, reduce fire risk, and improve resilience.

Working with willing landowners, investments would protect at least 100,000 acres of forested watershed by acquiring working forest conservation easements. Easements are already in place on 44,000 acres or more of the McCloud.

For both public and private forests, investments would target thinning, riparian area restoration, and meadow area restoration. These investments would cost less than $200 million but would result in twice the quantity of water supplied by, for example, a desalinization plant at a fraction of the price.

The McCloud River basin on the eastern flanks of Mount Shasta encompasses 432,620 acres of interwoven public and private lands—a typical pattern for many of the state’s key watersheds.