FISHBIO: Fisheries research, monitoring, and conservation

January 28, 2013

It’s hard to find a “natural” river in California’s Central Valley. Significant changes over the past century, such as dams and water use, have altered the daily, monthly, and annual variations in river flow, or the hydrographs, of the valley’s rivers. At the same time, the landscape around those rivers has changed dramatically, shifting towards agriculture and urban development. In recent years, river managers worldwide have been striving to release more natural river flows, or flows that mimic the natural hydrograph of a river system. But just what is a “natural hydrograph” in a river system that has been thoroughly, and in some cases permanently, altered? The University of California at Davis and the Delta Science Program hosted a seminar this month and invited a panel of local experts to address that question.

While the seminar speakers voiced different opinions, they agreed on a take-home message: in a highly modified system like the Central Valley, we can’t use the hydrograph alone to restore our river ecosystems to a natural state. We also need corresponding changes to the way rivers connect with the landscape. Relying on river flow alone is like driving a car with only the steering wheel and no gas or brake pedals, one speaker described, pointing out the limitations of focusing on just one tool at a time. The panel speakers acknowledged that most landscape changes in the valley are irreversible, but were optimistic about opportunities to integrate the landscape and the hydrograph to benefit fish and wildlife. For example, researchers found that the rate of spring snowmelt in the Sierra Nevada Mountains is a naturally predictable cue for many species, such as frogs and Chinook salmon. Spring snowmelt recession rates are a relatively easy measurement to discuss with stakeholders, and can be modeled ecologically and economically for cost-benefit analysis under various water operation scenarios.

To broaden the perspective, one presentation offered examples of flow management from around the world, including an intriguing list of environmental flow management principles from South Africa. These included retaining continuous flow year round in naturally perennial rivers, and retaining certain floods at full magnitude and eliminating others, rather than preserving all floods at diminished levels. The keynote speaker, Dr. Geoffrey Petts from the University of Westminster, also reminded the panel that we must consider river management in a world of “uncertain environmental change.” The United Kingdom is still reeling from a year of dramatic weather patterns that has left many in Britain wondering what climate change may bring.

The seminar follows on the heels of the publication of California’s State Water Resources Control Board’s preferred alternative changes to the Water Quality Control Plan for the San Francisco Bay-Sacramento/San Joaquin Delta Estuary, presented at the seminar. One of the goals of the State Board’s flow objective for the San Joaquin River basin is to include “flows that mimic the natural hydrographic conditions to which native fish species are adapted.” Clearly, the debate over what is natural will continue well into 2013. If you are curious about the SWRCB plan and you’re feeling ambitious, dive into the full document, about 2,000-pages of information. Otherwise, you can stick to the Executive Summary, a mere 61 pages.

This post featured in our weekly e-newsletter, the Fish Report. You can subscribe to the Fish Report here.

Tags: river flow measurement, rivers, water management

Print This Post

Restoration

The rabbit and the coyote brush

January 23, 2013

Since we are pretty fish-centric people here at FISHBIO, when we think of floodplains we tend to think of Chinook salmon and Sacramento splittail. But a recent visit to the San Joaquin River National Wildlife Refuge near Modesto with the organization River Partners reminded us that many other creatures make use of floodplain habitats as well. River Partners has been restoring wildlife habitat in the Central Valley for many years, and they focus on the bigger picture: how these habitats benefit the ecosystem as a whole. Their restoration projects in the refuge have taught them the importance of incorporating suitable habitat for various birds and terrestrial animals in floodplains. For example, the riparian brush rabbit (Sylvilagus bachmani riparius, shown above), an endangered native species that has been reintroduced to the refuge, needs to escape to higher ground during floods. As with many riparian areas in the Central Valley, “higher ground” often means levees. However, most levees are intentionally stripped of vegetation due to a controversial claim that plants destabilize the structures (see Levee improvements). This poses a problem for the rabbits: escaping floods means exposure to predators.

Like most extreme events in nature, floods are a double-edged sword that can prove a blessing to fish and a danger to rabbits. River Partners has worked to provide shelter for the rabbits and other species during floods by re-vegetating some levees with native plants such as California wild rose (Rosa californica), California blackberry (Rubus ursinus), and coyote brush (Baccharis pilularis; shown above). Furthermore, they have created a network of “bunny mounds” to offer wildlife additional high-ground refugia in the event of a flood. To check out this restored habitat, stroll along the new Pelican Nature Trail in the refuge, which is part of the larger San Luis National Wildlife Refuge Complex.

Tags: floodplains, habitat, habitat restoration, levees, native species, revegetation

Print This Post

Restoration

Plant a tree, help a salmon

January 18, 2013

Do you like working outdoors? Want to help restore important fish habitat on the Stanislaus River? FISHBIO and River Partners are looking for volunteers to plant native trees at Honolulu Bar on Saturday, January 26, from 10 am to 1 pm. All the planting tools will be provided, along with drinks and snacks. We recommend bringing work gloves and rubber boots, since we’ll be wading across a shallow channel to get to the planting site. There will be waders or hipboots available for anyone who doesn’t have boots.

Volunteers will get to see the handiwork of our latest restoration project first hand. The lower Stanislaus River is crucial habitat for steelhead trout and fall-run Chinook salmon. But during the Gold Rush, dredges destroyed many of the large stretches of silt-free gravel that the fishes need to spawn and their eggs need to develop. Last year, we completed a project with the Oakdale Irrigation District, the U.S. Fish and Wildlife Service, CBEC, and River Partners to restore the floodplain at Honolulu Bar (see Restoration complete). We used some heavy machinery to level the steeply sloped banks of the island so water could flood over it, and hauled gravel to replenish spawning beds. We also cleared invasive vegetation that had taken over the site, such as tree-of-heaven and Himalayan blackberry (see On the invasive species battlefield). Now it’s time to replant native species that belong in this riparian habitat.

You can help us plant more than 100 cuttings of black willow, sandbar willow, and cottonwood trees. Native plants like these play many important roles in keeping river ecosystems healthy. They shade the water and keep it cool, stabilize the bank, filter sediments, and provide habitat for the insects that young salmonids eat. So plant a tree, help a salmon. We will be meeting at the Honolulu Bar Recreation Area in Stanislaus River Parks. For more information, please contact Jason Guignard at jasonguignard@fishbio.com.

Tags: invasive species, native species, plants, Restoration, volunteer

Print This Post

Restoration

A river undammed…

November 14, 2012

On a recent trip to the Pacific Northwest one of our fisheries biologists visited the Elwha River on Washington’s Olympic Peninsula. The Elwha is the site of one of the most ambitious dam removal projects undertaken in North America to date. Two dams, Glines Canyon (constructed in 1927) and Elwha (constructed in 1913), have been removed in less than a year. The removal project allows for passage of five Pacific salmon species (Chinook, chum, coho, pink, and sockeye) that once inhabited the Elwha. The project, which began in 1992, has been a significant undertaking by the National Park Service, United States Geological Survey, National Oceanic & Atmospheric Administration, Washington Department of Fish and Wildlife, and the Lower Elwha Tribe.

After nearly 100 years of sediment buildup and large woody debris accumulation in the upstream ends of each reservoir, the Elwha is finally moving those materials out. In the process, the river is depositing new logjams and point bars that will increase the habitat diversity in the river channel. The project also opened up almost 70 miles of nearly pristine riverine habitat in Olympic National Park for salmon and steelhead.

Tags: dam removal, Elwha River

Print This Post

Restoration

Restoration complete

October 3, 2012

Pre-construction; instream island over-run with non-native plants

Post-construction floodplain bench; juvenile salmon rearing habitat

Last week marked the end of the construction phase of the Honolulu Bar Floodplain Enhancement Project (HBFEP; see video) and it almost felt like a celebration of all the hard work and dedicationthe Oakdale Irrigation District, U.S. Fish and Wildlife Service and other partners put forth this summer at Honolulu Bar. Recently, FISHBIO had the opportunity to participate in the 12th Annual Tuolumne County Natural Resource Summit, where we set up a display on the multifaceted HBFEP and many of our fisheries monitoring efforts in the tributaries of the San Joaquin Basin. The summit was sponsored by Pacific Gas & Electric Co. and the U.S. Forest Service and was open to the public. Many Tuolumne County residents attended and were thrilled to have the opportunity to interact with summit presenters such as Congressman Tom McClintock, Assemblywoman Kristin Olsen and Tuolumne County Supervisor Randy Hanvelt. Also presenting were Pete Kampa from The Tuolumne Utility District and Chris Horgan from the Stewards of the Sequoia. The topics presented and discussed often hinged on water management and public use issues; recognizing that water is one of, if not the most important factor influencing natural resources in the western United States. It was an absolute pleasure to be able to talk fisheries with public officials and the general public. It became obvious very quickly that there are many people in Tuolumne County and the Central Valley who love the outdoors and have a strong interest in what happens to the lakes and rivers in California. We were pleasantly surprised by how many people had visited the lower Stanislaus River and were aware of the positive efforts being made to help alleviate the problems faced by anadromous fish species like Chinook salmon and steelhead.

Tags: Floodplain, Restoration

Print This Post

Restoration

Replenishing a river

August 8, 2012

As with many rivers in California, the Stanislaus River has a deficit of good quality gravel for salmon and steelhead spawning. During the Gold Rush era large shovel dredges processed vast quantities of gravel and deposited the tailings in piles, usually adjacent to the stream. One such tailing in the Stanislaus River (Honolulu Bar) formed a large in-stream island and a side channel that was not accessible to fish under most flows. We are working with the Oakdale Irrigation District (OID) and the U.S. Fish and Wildlife Service’s Anadromous Fish Restoration Program (AFRP) to decrease the island elevation, so that it will become inundated under typical spring flows and provide more juvenile salmonid rearing habitat. Gravel removed from the island is being returned to the river channel to replenish spawning beds.

The groundwork for this project began with the removal of existing vegetation on the island—mostly undesired, non-native species—to expose the stockpile of coarse gravel below. Using excavators and front loaders, crews are now extracting the gravel, sorting, and washing it before strategically placing it back into the river channel. Delayed by high flows last year, this work is taking place during the lowest flow of the year to allow heavy equipment to access the river. The team is working quickly, since this project must be completed before fall-run Chinook begin their annual spawning migration.

Tags: Restoration

Print This Post

invasive species, Restoration

On the (invasive species) battlefield

July 20, 2012

Whether you are restoring degraded habitat or trying to preserve natural landscapes, invasive species pose management challenges. Extricating well-established, invasive plants, as we are doing at a restoration site along the Stanislaus River, is a daunting task. We are clearing several acres dominated by tree-of-heaven (Ailanthus altissima) and Himalayan blackberry (Rubus armeniacus). Despite their lofty names, these plants are prolific and can quickly out compete native species in the riparian zone. Invasive plant removal can be achieved through various chemical, biological, and mechanical methods, but for our circumstances mechanical removal is the best option. Mechanical removal includes using saws, chains, or blades to dig, rip or cut undesirable plants. This method is usually labor intensive if done by hand, but tools such as a tractor or excavator with a brush shredder attachment quickly chop aboveground vegetation. This type of removal usually requires multiple visits (3-4 per year) for several years to prevent regrowth. However, that won’t be necessary for this project, since we will be using bulldozers to remove several feet of soil and grade the banks of the river channel. The outcome of this work will be additional floodplain and rearing habitat for salmon and steelhead, eliminating some non-native invasive plants along the way is just an added bonus.

Tags: invasive species

Print This Post

Restoration, Steelhead

Sticker shock

January 20, 2012

Last week the National Marine Fisheries Service (NMFS) released the final Southern California Steelhead Recovery Plan outlining what needs to be done over the next 100 years to restore endangered steelhead to Southern California rivers and streams. Perhaps the most surprising aspect of the report is the $2.1 billion projected price.

Steelhead, the anadromous form of rainbow trout (Oncorhynchus mykiss), are divided into six Distinct Population Segments (DPS) in California. The Southern California DPS includes 32 coastal watersheds extending from the Santa Maria River to the Tijuana River at the U.S.-Mexico border. The Southern California Steelhead (SCS) DPS was federally listed as endangered by NMFS under the Endangered Species Act (ESA) in 1997, following a comprehensive status review of all West Coast steelhead populations. Southern California populations were once as high as 46,000 before the rapid land and water development following WW II, but now consist of less than 500 returning adults.

The population decline is attributed to the loss of 90 percent of the historic spawning and rearing habitat above dams and the dewatering of streams by water diversions. Other threats to steelhead include degraded habitat, introduction of non-native fish and amphibians, and point and non-point water pollution. The goal of the Recovery Plan is to “recover anadromous steelhead and ensure the long-term persistence of self-sustaining wild populations of steelhead across the DPS – and ultimately to remove southern California steelhead from the Federal List of Endangered and Threatened Wildlife.” The Recovery Plan identifies a number of Critical Recovery Actions such as modifying passage barriers and ensuring adequate instream flow to protect beneficial uses. It’s going to cost a lot and take considerable time to recover steelhead, but it will provide substantial benefits for both human and ecological communities.

Tags: Rercovery Plan, Steelhead

Print This Post

Restoration

Bulldozing barriers

October 12, 2011

Fish migration barriers are any obstacles that may interfere with or prevent the upstream or downstream movement of fish. These barriers can be caused by numerous natural and manmade structures such as culverts, dams or weirs, cascades or falls, woody debris (logjams), beaver dams, and instream road crossings. Unimpeded fish passage is especially important for anadromous fish like salmon and steelhead, which migrate both downstream and up in order to complete their lifecycle.

Over the past two decades fisheries managers have become increasingly aware of fish passage barriers and have been working with local agencies to address passage issues. In this case, Stockton East Water District is taking steps to improve fish passage in the Calaveras River and Mormon Slough. A study by the California Department of Water Resources’ Fish Passage Improvement Program produced an inventory and evaluation of barriers on the Calaveras River system, a tributary to the San Joaquin River in California’s Central Valley.

One of the most difficult barriers for fish to pass in the Calaveras River system was a flashboard dam in the Stockton Diverting Canal, pictured above. A flashboard dam, is a removable dam created using boards fitted onto a concrete ‘apron’. The lower photo shows the flashboards in place. Between late spring and early fall the boards hold water back, creating pools. During the winter months the flashboards are removed, as shown in the top photo, but in this case the concrete apron remained an obstacle to migration. During low flow conditions the steep slope of the channel just downstream of the concrete apron would become a 5-foot drop, lined with rip-rap, impassible to upstream migrating steelhead (Oncorhynchus mykiss). In an effort to improve fish passage at this location, a re-designed rock ramp fishway and ‘boulder-weir’ style grade control structure is currently being constructed and is near completion. Boulder weirs are designed to create natural steps, and in this case carefully placed lines of boulders arranged in an arch pointing upstream slope upward at the bank to concentrate low flows to the center of the channel. The new contoured channel will spread the original 5-foot drop across about 100 feet of river length, making the structure passable under most low flow conditions (greater than 15 cfs) when flashboard dam is out. This is the first of four barrier removal projects planned for the next few years.

Tags: fish passage barriers

Print This Post

Restoration

A small window of opportunity

September 16, 2011

Many rivers in the Western U.S., including the Stanislaus River, have been severely degraded over time due to dams, water diversions, and gold and aggregate mining. During the 1940s over 1 million cubic yards of gravel were removed from the lower Stanislaus River channel, eliminating 55% of the spawning riffles over an 8 mile stretch of river. The upstream dams block coarse sediment supply and worsen the problem, so the remaining riffles become armored in sediments and smaller as they erode away. Unfortunately, the limited amount of spawning habitat on the Stanislaus only supports redds from about 1,250 female Chinook salmon and late arriving females may create redds on top of early redds (i.e. redd superimposition), killing the incubating eggs (Mesick 2001). To help mitigate this problem, the U.S. Bureau of Reclamation (USBR) is required by the Central Valley Project Improvement Act (CVPIA) to increase the availability of spawning gravel and rearing habitat by replenishing gravel in the river. The USBR, in cooperation with the California Department of Fish and Game, has added 17,000 tons of gravel since 1997 with an additional 5,000 tons added this year (USBR). The USBR will continue adding an additional 3,000 tons annually to meet the state and federal water operations target of placing 50,000 cubic yards of gravel by 2014 (OCAP). With above-average snow pack in California this year, river flow has been high all summer making it difficult to conduct in-stream work, but the USBR used a small window of opportunity to reduce the flow from 2,000 to 400 cubic feet per second for two weeks in order to add gravel before fall-run Chinook spawning gets underway.

Tags: spawning gravel