Hooray for Floodplains, Food Webs and Fish!


This excellent video describes the Nigiri Project at Knaggs Ranch in the Yolo Bypass. Watch as these students explain the importance of floodplains to producing food for salmon fry. These young fish move from the gravel spawning beds on the Sacramento and Feather Rivers toward the ocean. Due to our flood control levees they have lost 95% of their floodplain feeding grounds.

Lulu the Wonder Dog sniffing out the fish at Knaggs Ranch.

Lulu the Wonder Dog sniffing out the fish at Knaggs Ranch.

Farmers in the Yolo Bypass have been working with UC Davis and government scientists to prove that fish will grow at record rates on rice fields when flooded in the winter time. As the fields are drained, the fish continue their journey to the ocean and the food is flushed into the Delta where it provides food for Smelt and other native fish.

Local stakeholders have worked out an integrated plan that meets flood, fish, farm and waterfowl needs. It is now before government agencies to seize the opportunity for breakthrough.


Nigiri Project Wraps Up Another Successful Year

You can read about the conclusion of another successful year of salmon fish fattening on Knaggs Ranch rice fields on this San Francisco Chronicle cover story.  Or…

Salmon ready for their journey to the PacificOnce upon a time the California native salmon population was dwindling. Every year the fish hatcheries would release hundreds of thousands of salmon to have a miniscule return because the river was so channelized that the fish could not find the important floodplain habitat where they need to put on weight and delay their migration to sea to a time when the upwelling off the coast of San Francisco provides food.

Then one day a Department of Water Resources scientist Ted Sommers had an idea. He placed a 100,000 tagged hatchery fish in the main stem of the Sacramento River and 100,000 tagged hatchery fish in the Toe Drain of the Yolo Bypass (a flood control area that can still operate like a floodplain). He caught 16 fish in the Bay trawls at the end of a few weeks and the Bypass fish were noticeably bigger. And then Carson Jeffres, a grad student at UC Davis decided to build off of this with an experiment on one of the few remaining undammed rivers in NorCal. He created an experiment on the Cosumnes River, which resulted in the now “famous” cooler picture of floodplain salmon three times the size of the other salmon. This resulted in the National Marine Fisheries Service requiring 17,000 acres of floodplain habitat in the Sutter and Yolo Bypasses as part of the Biological Opinions for the water agencies to continue pumping water through the Delta.

In some ways this seemed like an “all is lost” moment because the agencies interpreted that as flooding the Bypasses wall-to-wall for long periods of time and this would have made it tough for the farmers and duck clubs in the Bypass to survive and then this would have compromised the Bypasses as a flood control structure.  Until one day John Brennan, a farm manager/appraiser/rice drier owner put together a group to buy Knaggs Ranch and experiment with using rice fields as surrogate salmon floodplain habitat. And now 3 years later the experiment has proven that the rice fields with water held for up to 6 weeks create “Floodplain Fatties”. And a coalition of farmers, scientists, fish advocates, county folks, wildlife area managers, and agencies are proposing a management system that is compatible with all of the existing uses in the Yolo Bypass. This year is a drought year and naturally really tough on fish. Access to the floodplain will give them resiliency to survive this kind of water year and in the future sea-level rise and warmer temps. It is also Conservation Measure 2 in the Bay Delta Conservation Plan.

Nigiri Project 2013

The experiments to test how well salmon fry will thrive on “surrogate wetlands” (a.k.a. rice fields) is in middle of year two.  The test pods were expanded from 5 acres to 10 2-acre ponds at Knaggs Ranch.  Each of the fields, now ponds, has one of three treatments: fallow with weeds, rice stubble and stomped rice (stubble rolled into soil, twice).  In addition, there are cages within the first pond with all three treatments and the telemetry to track fish behavior using technology like that in Fastrak.

Equipment in pond tracks what type of land treatment the fish prefer: rice stubble, weeds or stomped rice.

Equipment in pond tracks what type of land treatment the fish prefer: rice stubble, weeds or stomped rice.

Another experiment is comparing the success rate of fish that spend time on the floodplain getting fat for 4-6 weeks before swimming to sea, versus going directly into the Toe Drain or into the Sacramento River.  These experiments are coordinated by a Science Team led by Jacob Katz with California Trout.  Scientists from Department of Water Resources, UC Davis Watershed Science Center, National Marine Fisheries Service, CA Department of Fish and Wildlife and US Bureau of Reclamation all collaborate to design the experiments and manage the projects in the field.

The farm manager, John Brennan, is an active partner– especially in solving problems such water supply and field designs. At the beginning of February there was a concern about possible breaks in the field checks.  The good weather relieved those pressures but created other concerns.

The warm weather raised concerns about salmon tolerance for temperature. The sunshine also provided the conditions for the algae bloom that feeds the bugs that feed the fish.  The food is so abundant that the fish are growing at twice the rate of last year, reaching sizes at 3 weeks that were measured after 6 weeks in 2012.

Pilot 2 – Growth 22 days (1)

The floodplains also give the fish space to hang out with few predators while the ocean conditions change to be more salmon friendly.  In another few weeks the Science Team will measure, count and release the fish in to the Toe Drain to swim out to sea. Their report will be available sometime this summer.

Nigiri Project: salmon on rice

The Yolo Bypass is tucked between Woodland and Sacramento and yet when you are in the middle of it you feel a million miles away.  My car stirred great blue herons and snowy white egrets as I drove along the levee to meet John Brennan and Emily James.  I had forgotten just how great is the wingspan of these birds so I slowed and paid attention to their elegant flight.

John and Emily directed me to park my car and I hopped into their truck. Our first stop was at the top of the property where they operate a  seasonal earthen dam to direct water from the Ridge Cut Canal at the bottom of the Colusa Drain into the fields. This is the water that floods up the rice fields in winter to decompose rice stubble and provide waterfowl habitat. With duck season over at the end of January,most rice farmers or duck club managers have pulled out the boards on the fields and drained them. They’ll go on vacation with their duck club widows and then return to begin prepping the fields for planting rice in April.

There are other crops grown in the Bypass–safflower, sunflowers, tomatoes–and cattle and sheep graze, but in this section the predominance of clay soils makes it good for growing rice.  And there is a long established symbiosis between waterfowl and rice.   What seems like a new idea is that this seasonal floodplain might also be ideal for fish.

In 2001 Ted Sommers and colleagues published a paper about the importance of floodplains as temporary Chinook salmon habitat.  It caused some excitement at the time, but it took just over 10 years before he was able to stage an experiment with hatchery salmon fry in the Yolo Bypass.

Before the levees, when the salmon runs were much higher than today’s 50,000 fish, the young salmon would regularly find themselves out on the various floodplains that bordered the Sacramento River where they were  able to find a safe place to feed and grow before heading out to sea.

This year the seasonal floodplain was recreated on the lower five acres of a Yolo Bypass rice field. Ted’s crew with the Department of Water Resources (DWR) and a crew from UC Davis set up experiments with 10,000 hatchery fish: releasing them to eat and grow from the end of January to mid-March.

Recently I was able to visit the intentional floodplain to see the conclusion of the experiment.  The two crews worked together to catch and count the fish before they released them into the Bay Delta.

A portion of the fish had microchips inserted that made it possible to wand them and record their growth rates. The DWR study is straightforward: fish in, fish out, fish size and fish health.Their preliminary findings showed very healthy fish that had doubled in length and quadrupled in size.  The UC Davis study designed by Peter Moyle and Jacob Katz prepared various rice stubble treatments and made fish pens within the floodplain to hold fish and see if their growth and survival rates varied with the various treatments. These are the black pens in the midst of the flooded field.

The UC Davis grad students were also taking random samples of fish to measure and a few were packed to take back to the lab to check for other growth indicators.

On the day I visited the mood was jubilant.  Everyone was working to count the fish before the forecasted storm made it harder to get into the site.  They were also having a good time doing what they love most.

John Brennan the farm manager for the Cal Marsh & Farm Ventures where this project is taking place is one of the most enthusiastic and well-spoken of the team members.  He has spent hours explaining the project to reporters and others who need to understand what the potential is for fish in the Yolo Bypass.

John can envision a wayto manage for fish on the their rice fields on a seasonal basis. And he explains how this 5 acre project can be incrementally expanded until 1,000,000 small salmon safely grow to a size where they have a better shot at making it to adulthood.  If they can improve the return rate of the fish to 2% , then this site can potentially grow the salmon run from 50,000 to over 70,000 and so on.

John thinks the project is important because it stresses the integrated management of a working landscape, which he sees as the path forward, with the agricultural community, as the true stewards of the land, taking a lead role in the designing and implementing the environmental solutions of the next generation.

It is also an important lynchpin in the conservation strategy for managing the water supply operations in the Delta under the current Biological Opinion (that is the opinion by the fish agency NMFS about what steps must be taken to keep the salmon from becoming extinct). It becomes even more important in the proposed Bay Delta Conservation Plan.

The idea is controversial.  Yet, the Yolo Basin has long had multiple uses as farmers and wildlife refuge managers have worked together to provide flood protection, food, and habitat.  This is another benefit that can be accommodated if good will can prevail.