SESSION TITLE: Achieving Multi-Benefit and Sustainable Flood Management in California’s Central Valley
SESSION LENGTH: 2 hours
ABSTRACTS: 5included in one document for this proposed session
TITLE: Fish, Farms, and Fowl on the Yolo Bypass: measuring the benefits and impacts of floodplain restoration.
AUTHORS: John Cain, Conservation Director, American Rivers (presenter); Katie Jagt, P.E., Consulting Engineer to American Rivers; Seth Lalonde, Environmental Scientist, NewFields; and Mark R. Tompkins, P.E., Ph.D., Engineering Geomorphologist, NewFields
ABSTRACT: The Yolo bypass is a multi-benefit flood management facility intentionally managed to reduce flood risk for Sacramento, provide habitat for migratory birds, and produce agricultural crops. Research demonstrating the value of inundated floodplain for juvenile salmon has led state and federal agencies to consider changes to Fremont Weir that would allow active management of the bypass for fisheries benefits in addition to its other purposes. Fremont Weir is a 1.75 mile-long, seven-foot high concrete structure located at the upstream end of the Yolo Bypass, which passively allows water to flow into the bypass only when the stage of the Sacramento River exceeds 33.5 feet – the elevation of the weir crest. State and federal planners are now evaluating designs that would create an operable, gated-opening in Fremont Weir to allow fish and floodwaters onto the bypass when flows are significantly below the crest of the weir. Farmers and waterfowl managers are concerned that more frequent inundation would reduce benefits for agriculture and waterfowl. We used the estimated annual habitat (EAH) method (Matella and Jagt, 2013) to evaluate the benefits and impacts of different scenarios on fish, waterfowl, and agriculture. EAH generates area-duration-frequency curves to quantify the area of floodplain inundated for a specified duration, timing, and frequency and can thus be useful in determining the suitability of a floodplain as “habitat” for fish, wildlife, or even agricultural crop species. Operational scenarios that keep the proposed weir gate open later in the spring provide greater benefit for fish but with more impact to agriculture and waterfowl. The total benefits and impacts of later opening is limited, however, because late season inundation already occurs under existing conditions when high flows spill over the weir crest in wet years. Operations of a gated-opening, however, could allow better management of these late season events for fish while minimizing new impacts to agriculture and waterfowl.
TITLE:Advanced data integration and visualization tools to improve the planning, design, and evaluation of floodplain habitat for multi-objective flood management projects.
AUTHORS: Mark R. Tompkins, P.E., Ph.D., Engineering Geomorphologist, NewFields (presenter); Craig Williams, SeniorEnvironmental Scientist,California Department of Water Resources; and Romain Maendly, P.E., Water Resources Engineer, California Department of Water Resources
ABSTRACT: Multi-objective flood management planning is difficult.Much of this difficulty is rooted in the fundamental disconnect that typically exists between flood management engineers and biologists and ecologists who work on aquatic ecosystems within flood management systems. These two disciplines bring different training, problem solving approaches, primary objectives, and perhaps most importantly, data needs and analytical approaches to the tasks of multi-objective flood management planning. This often leads to disconnected engineering and ecological planning and analysis that result in poorly integrated flood management plans. Using Big Data technologies developed to support other sectors with multi-objective planning needs, we’ve developed a suite of analytical tools that combine engineering, ecological, and other relevant data types in an analytical and visualization framework that allows engineers and ecologists to jointly view, evaluate, and assess tradeoffs between flood management and ecological performance of alternative flood system configurations. At the core of this suite of tools is an implementation of the Estimated Annual Habitat (EAH) metric that allows rapid communication and iteration around floodplain habitat planning. This advanced, technology-empowered approach provides major improvements in the speed and transparency of floodplain habitat design and ultimately leads to more effective integrated flood management planning for multiple objectives.
TITLE: Assessment of flood management systems' flexibility with application to the Sacramento River basin, California, USA
AUTHORS: Desirée Tullos, Ph.D., P.E., Associate Professor, Oregon State University (Presenter) and Kara DiFrancesco, Ph.D. Candidate, Oregon State University
ABSTRACT: The recent rise in the variability and uncertainty of hydrologic conditions has lead water resources managers and researchers to promote the concept of increasing the flexibility of flood management systems. Building upon previous studies of flexibility in the fields of information technology and Social-Ecological Systems, among others, we outline an approach to investigate how structural and non-structural flood management actions relate to system flexibility. We assess flexibility using metrics that describe flexibility by five characteristics: slack, redundancy, connectivity, adjustability, and collaboration/ cooperation. We apply this flexibility assessment to four proposed flood management strategies, each with a unique suite of management actions, for the Sacramento River Basin in California, USA. The foci of benefits differ between the four different flood management strategies, with varying emphasis on protecting urban communities, rural and agricultural improvements, and ecosystem restoration, with a range of impacts on the five flexibility characteristics. Across all strategies, we find a disproportionate emphasis on increasing slack in the current system, as well as a concentration of expenditures towards structural versus non-structural components. Only two of the assessed strategies improve all five flexibility characteristics, and these two strategies also include the greatest number of actions that provide flexibility benefits. We do not find a clear link between these more flexibility strategies and their time and cost effectiveness in terms of reduction in damages. Through this application of the assessment to the Sacramento River flood management system, we illustrate some of the tradeoffs of increasing flexibility for managing floods under uncertainty, and discuss implications for flood infrastructure development in the developing world.
TITLE: Design and Performance of a Multi-Benefit and Sustainable Flood Management Project on the Sacramento River Floodplain.
AUTHORS: Anthony Falzone, C.F.M, Geomorphologist, NewFields (presenter) and Paul Frank, P.E., Ecological Engineer, NewFields
ABSTRACT: Impacts associated with construction of a pump station to replace the Red Bluff Diversion Dam on the Sacramento River were mitigated through construction of a three-quarter mile long, 23 acre perennial, off-channel open water and riparian wetland habitat in East Sand Slough, an off-channel area immediately adjacent to the Sacramento River. Since the 1960s, East Sand Slough has been inundated annually by backwater from Red Bluff Diversion Dam. The new off-channel habitat area will be connected to the main stem Sacramento River at low flow in three locations. The design for the habitat contains open water, riverine wetlands, and riparian shrub scrub environments intended to support habitat for rearing fish and establish native vegetation communities adapted to the site conditions. The design analyses required an understanding of the complex hydraulic and sediment flow patterns at both these connection sites and in the newly constructed channel to understand habitat conditions and avoid maintenance problems due to erosion or sedimentation that could threaten the long-term viability of the constructed habitat. We used the hydrodynamic and sediment transport modules of the Bureau of Reclamation's SRH2D model to simulate a range of flow events in the proposed design configuration. We were able to validate the hydraulic and sediment transport predictions of the model by comparing existing conditions model results with sediment transport data collected during an approximately 5-year flow event, which occurred on Sacramento River towards the end of the design process (approximately 95,000 cfs in March 2011). Additionally, we were able to assess performance of the project a during another high flow event (approximately 70,000 cfs in December 2012) at the tail end of construction of the project. Lastly, we present observation on performance of the project two years post-construction.
TITLE: Measuring the compatibility of agricultural crops with periodic floodplain inundation.
AUTHORS: Alejo Kraus-Polk, Research Associate, American Rivers (presenter); Mary Matella, Ph.D., California Sea Grant Fellow, California Coastal Commission; and John Cain, Conservation Director, American Rivers
ABSTRACT: Restoration of inundated floodplain habitat is essential to restoration of Chinook salmon populations and other fish and wildlife species in California and beyond. Several state and federal plans call for restoration of thousands of acres of floodplain habitats in the Central Valley of California, but farmers fear that floodplain restoration activities would or diminish agricultural production.
We have adapted a newly developed approach for measuring floodplain habitat suitability to quantify the suitability of periodically inundated floodplains for various agricultural crops. The estimated annual habitat (EAH) method (Matella and Jagt, 2013) generates area-duration-frequency (ADF) curves to quantify the area of floodplain inundated for a specified duration, timing, and frequency and can thus be useful in determining the suitability of a floodplain as “habitat” for a wild species or a cultivated agricultural crop. We plotted the timing, frequency, and duration of inundation on floodplain lands along the lower San Joaquin River and compared it to cropping patterns and inundation tolerances of the agricultural crops planted on the same lands. We then used production value data from the San Joaquin County Agricultural Commissioner to determine how fully removing levees would impact the regional agricultural economy. Due to extreme hydrograph alteration by upstream dams, the impact of levee removal on agricultural production value is surprisingly small. For example, a late May 15,000 cfs flood event (occurring approximately 1 in 7 years) would decrease production value by $4,000,000 - slightly over a quarter of the total gross production value of the total setback area.
This analysis demonstrates that it may be possible to advance floodplain restoration for fish and bird habitat during the winter months without significantly impacting agricultural activities during the growing season. More broadly it demonstrates how the EAH method can be used to calculate the benefits that levees provide for agricultural production