Much research in the Delta has focused on foodweb dynamics, stimulated by evidence that low productivity of plankton is linked to declines in several fish species including the endangered delta smelt. Pseudodiaptomus forbesi is the most abundant copepod (small crustaceans) in the Delta in summer. It is an important food source for many fishes and makes up about half of the food of delta smelt. This study focuses on the feeding, reproduction, and growth of copepods as essential foodweb support for fishes. This work investigates four diverse habitats including two open-water channels and two shallow habitats. The researchers will measure copepods' feeding rates on microscopic plants and animals, and relate feeding to their rates of growth and reproduction. Computer models will be used to estimate their movement and death rates. These results will show the sources of nutrition used for growth and reproduction of these key organisms. Results will inform how food webs respond to large scale changes in the Delta ecosystem, for example, restoration and the Sacramento wastewater treatment plant upgrade.
In June 2004, a 350-foot levee section gave way west of Stockton, flooding crops and more than a dozen homes, and challenging state officials to protect the state's water supply. What is the risk of that happening again somewhere in the Delta? In light of agricultural fields sinking, the sea level rising, more frequent and severe floods occurring, and earthquakes looming, improvements are estimated to cost $3.8 - $4.3 billion over the next few decades. This study combines 3-D representations with information on the levee's structure to analyze how different levees respond to floods, sea level rise, and earthquakes. State officials released the last Delta Risk Management Strategy a decade ago. Since then, scientists have collected significant amounts of data and have developed new procedures to compute the risk of failure. This work will produce new Delta-wide data sets important for characterizing the hazards coming from floods and earthquakes. It will also develop the best method to conduct levee hazard assessments. Applying this new method will ensure wise investments and effective threat mitigation Delta-wide.
