Yolo Bypass is an ecological feature of the Bay-Delta ecosystem in California that provides floodplain habitat for spawning and rearing of Sacramento Splittail (Pogonichthys macrolepidotus) and rearing of juvenile Chinook Salmon (Oncorhynchus tshawytscha) when inundated. We used outputs from 10 climate change models for two Representative Concentration Pathways (RCPs) for greenhouse gas concentrations to assess the effects of climate change on the frequency, duration, and timing of flood flows in Yolo Bypass. We also assessed a planned notched weir modification to the primary weir that controls inflow from the Sacramento River into Yolo Bypass that has been designed to allow the bypass to be inundated at lower river flows.

Largely supported by the Interagency Ecological Program (IEP), California Department of Water Resources (DWR) has operated a fish monitoring program in the Yolo Bypass, a seasonal floodplain and tidal slough, since 1998. The objectives of the Yolo Bypass Fish Monitoring Program (YBFMP) are to: 1. Collect baseline data on water quality, chlorophyll, lower trophic level biota, and fish in the Yolo Bypass to monitor spatial and temporal changes in trends and abundance. 2. Analyze and communicate Yolo Bypass data with interested parties and the scientific and management communities to address pertinent management-related questions. 3. Provide technical expertise on Yolo Bypass aquatic ecology and monitoring and sampling methods. The YBFMP operates a rotary screw trap and fyke trap and conducts biweekly beach seine and lower trophic surveys in addition to maintaining water quality instrumentation in the bypass. The YBFMP informs the restoration actions that are mandated or recommended in these plans and provides critical baseline data on the ecology of the bypass and how it interacts with the broader San Francisco Estuary. YBFMP’s data is often accompanied by information on whether the Yolo Bypass is inundated, as water quality, and species composition and abundance can be greatly altered during inundation. This dataset was created to consistently estimate inundation over time. Estimating inundation in the Yolo Bypass is usually done by referencing stage height in the Sacramento River at Fremont Weir. Stage height is the water level of the river. Fremont Weir is upstream of the Yolo Bypass and when Fremont Weir overtops, or reaches its monitoring stage, the Yolo Bypass is considered inundated. This dataset is originally published on EDI and linked to this CNRA open data portal.

Understanding the effects of climate change is a substantial challenge in estuarine systems because the mixing of freshwater and ocean water adds complexity to climate change projections. Such climate change projections have been conducted in the San Francisco Estuary as part of the U.S. Geological Survey’s CASCaDE Project. In this project, we assessed downscaled air temperature data from 10 Global Climate Change models under 2 Representative Concentration Pathway (RCP) trajectories for greenhouse gas concentrations for three regions of the upper San Francisco Estuary: Suisun and Grizzly Bays, Suisun Marsh, and the legal Delta. We also utilized previously derived regression models to estimate future water temperatures at 16 locations within the upper estuary based on the projected air temperature data.

Largely supported by the Interagency Ecological Program (IEP), California Department of Water Resources (DWR) has operated a fish monitoring program in the Yolo Bypass, a seasonal floodplain and tidal slough, since 1998. The objectives of the Yolo Bypass Fish Monitoring Program (YBFMP) are to: 1. Collect baseline data on water quality, chlorophyll, lower trophic level biota, and fish in the Yolo Bypass to monitor spatial and temporal changes in trends and abundance. 2. Analyze and communicate Yolo Bypass data with interested parties and the scientific and management communities to address pertinent management-related questions. 3. Provide technical expertise on Yolo Bypass aquatic ecology and monitoring and sampling methods. The YBFMP operates a rotary screw trap and fyke trap and conducts biweekly beach seine and lower trophic surveys in addition to maintaining water quality instrumentation in the bypass. The YBFMP informs the restoration actions that are mandated or recommended in these plans and provides critical baseline data on the ecology of the bypass and how it interacts with the broader San Francisco Estuary. YBFMP’s data is often accompanied by information on whether the Yolo Bypass is inundated, as water quality, and species composition and abundance can be greatly altered during inundation. This dataset was created to consistently estimate inundation over time. Estimating inundation in the Yolo Bypass is usually done by referencing stage height in the Sacramento River at Fremont Weir. Stage height is the water level of the river. Fremont Weir is upstream of the Yolo Bypass and when Fremont Weir overtops, or reaches its monitoring stage, the Yolo Bypass is considered inundated. This dataset is originally published on EDI and linked to this CNRA open data portal.

The data release contains data for the spatial and temporal variability of nutrients and related water quality parameters at high spatial resolution in the North Delta in the Sacramento-San Joaquin River Delta of California, USA. The data set includes nitrate, ammonium, phosphate, dissolved organic carbon, temperature, conductivity, dissolved oxygen, turbidity, and chlorophyll. Data-collection cruises were conducted over two days in March 2017 during a high flow event when Sacramento Valley flood waters inundate the Yolo Bypass.

The data release contains data for the spatial and temporal variability of nutrients and related water quality parameters at high spatial resolution in the North Delta in the Sacramento-San Joaquin River Delta of California, USA. The data set includes nitrate, ammonium, phosphate, dissolved organic carbon, temperature, conductivity, dissolved oxygen, turbidity, and chlorophyll. Data-collection cruises were conducted over two days in March 2017 during a high flow event when Sacramento Valley flood waters inundate the Yolo Bypass.

Largely supported by the Interagency Ecological Program (IEP), California Department of Water Resources (DWR) has operated a fish monitoring program in the Yolo Bypass, a seasonal floodplain and tidal slough, since 1998. The objectives of the Yolo Bypass Fish Monitoring Program (YBFMP) are to: 1. Collect baseline data on water quality, chlorophyll, lower trophic level biota, and fish in the Yolo Bypass to monitor spatial and temporal changes in trends and abundance. 2. Analyze and communicate Yolo Bypass data with stakeholders and the scientific and management communities to address pertinent management-related questions. 3. Provide technical expertise on Yolo Bypass aquatic ecology and monitoring and sampling methods. The YBFMP operates a rotary screw trap and fyke trap and conducts biweekly beach seine and lower trophic surveys in addition to maintaining water quality instrumentation in the bypass. Only juvenile and adult fish catch with associated water quality are presented in this dataset. The rotary screw trap sampling objectives are to: (1) examine species abundance and life stage of juvenile outmigrants and resident small-bodied fishes, (2) identify temporal and spatial patterns in fish abundance and species composition, and (3) examine the effect of physical and environmental conditions on these patterns. The fyke trap sampling objectives are to: (1) examine abundance of migrating and resident adult fishes, (2) identify temporal and spatial patterns in fish abundance and species composition, especially with regard to anadromous species, (3) examine the effect of physical and environmental conditions on these patterns, and (4) provide data on the timing and duration of species captured in the Yolo Bypass for comparison to those captured in other Sacramento Valley tributaries. The beach seine surveys are conducted in the Yolo Bypass’s perennial channel (Toe Drain), inundated floodplain, disconnected inundated ponds, and perennial ponds. The objectives of Toe Drain and inundated floodplain beach seine sampling are: (1) to examine species abundance and composition in different water year types and inundation conditions, (2) to spatially compare fish abundance and diversity in the Yolo Bypass, and (3) to estimate growth rates and densities of salmon in the Yolo Bypass versus the Sacramento River. The objectives for beach seine sampling in disconnected inundated ponds are: (1) measure the diversity and abundance of fish species stranded in ponds located in different regions and habitats, (2) to compare relative densities of fish before and after floodplain drainage, (3) to examine the sources of fish mortality in ponds including temperature, desiccation and predation, (4) to develop long-term annual Yolo Bypass stranding indices for reference locations, and (5) to examine relationships between annual stranding indices and physical variables such as hydrology and temperature. The objectives for seine sampling in the perennial ponds are: (1) to examine seasonal fish species abundance and diversity in the Yolo Bypass versus the Sacramento River and (2) to examine species abundance and composition in different water year types. The YBFMP serves to fill information gaps regarding environmental conditions in the bypass that trigger migrations and enhanced survival and growth of native fishes, as well as provide data for IEP synthesis efforts. YBFMP staff also conduct analyses of YBFMP monitoring data to address pertinent management related questions as identified by IEP. The Yolo Bypass has been identified as a high restoration priority by the National Marine Fisheries Service and US Fish and Wildlife Service Biological Opinions for Delta Smelt, Winter and Spring-run Chinook salmon and by California EcoRestore. The YBFMP informs the restoration actions that are mandated or recommended in these plans and provides critical baseline data on the ecology of the bypass and how it interacts with the broader San Francisco Estuary. Key

Largely supported by the Interagency Ecological Program (IEP), California Department of Water Resources (DWR) has operated a fish monitoring program in the Yolo Bypass, a seasonal floodplain and tidal slough, since 1998. The objectives of the Yolo Bypass Fish Monitoring Program (YBFMP) are to: 1. Collect baseline data on water quality, chlorophyll, lower trophic level biota, and fish in the Yolo Bypass to monitor spatial and temporal changes in trends and abundance. 2. Analyze and communicate Yolo Bypass data with stakeholders and the scientific and management communities to address pertinent management-related questions. 3. Provide technical expertise on Yolo Bypass aquatic ecology and monitoring and sampling methods. The YBFMP operates a rotary screw trap and fyke trap and conducts biweekly beach seine and lower trophic surveys in addition to maintaining water quality instrumentation in the bypass. Only juvenile and adult fish catch with associated water quality are presented in this dataset. The rotary screw trap sampling objectives are to: (1) examine species abundance and life stage of juvenile outmigrants and resident small-bodied fishes, (2) identify temporal and spatial patterns in fish abundance and species composition, and (3) examine the effect of physical and environmental conditions on these patterns. The fyke trap sampling objectives are to: (1) examine abundance of migrating and resident adult fishes, (2) identify temporal and spatial patterns in fish abundance and species composition, especially with regard to anadromous species, (3) examine the effect of physical and environmental conditions on these patterns, and (4) provide data on the timing and duration of species captured in the Yolo Bypass for comparison to those captured in other Sacramento Valley tributaries. The beach seine surveys are conducted in the Yolo Bypass’s perennial channel (Toe Drain), inundated floodplain, disconnected inundated ponds, and perennial ponds. The objectives of Toe Drain and inundated floodplain beach seine sampling are: (1) to examine species abundance and composition in different water year types and inundation conditions, (2) to spatially compare fish abundance and diversity in the Yolo Bypass, and (3) to estimate growth rates and densities of salmon in the Yolo Bypass versus the Sacramento River. The objectives for beach seine sampling in disconnected inundated ponds are: (1) measure the diversity and abundance of fish species stranded in ponds located in different regions and habitats, (2) to compare relative densities of fish before and after floodplain drainage, (3) to examine the sources of fish mortality in ponds including temperature, desiccation and predation, (4) to develop long-term annual Yolo Bypass stranding indices for reference locations, and (5) to examine relationships between annual stranding indices and physical variables such as hydrology and temperature. The objectives for seine sampling in the perennial ponds are: (1) to examine seasonal fish species abundance and diversity in the Yolo Bypass versus the Sacramento River and (2) to examine species abundance and composition in different water year types. The YBFMP serves to fill information gaps regarding environmental conditions in the bypass that trigger migrations and enhanced survival and growth of native fishes, as well as provide data for IEP synthesis efforts. YBFMP staff also conduct analyses of YBFMP monitoring data to address pertinent management related questions as identified by IEP. The Yolo Bypass has been identified as a high restoration priority by the National Marine Fisheries Service and US Fish and Wildlife Service Biological Opinions for Delta Smelt, Winter and Spring-run Chinook salmon and by California EcoRestore. The YBFMP informs the restoration actions that are mandated or recommended in these plans and provides critical baseline data on the ecology of the bypass and how it interacts with the broader San Francisco Estuary. Key

The Yolo Bypass Fish Monitoring Program (YBFMP) operates a rotary screw trap and fyke trap and conducts biweekly beach seine and lower trophic surveys in addition to maintaining water quality instrumentation in the bypass. The YBFMP serves to fill information gaps regarding environmental conditions in the bypass that trigger migrations and enhanced survival and growth of native fishes, as well as provide data for IEP synthesis efforts. YBFMP staff also conduct analyses of YBFMP monitoring data to address pertinent management related questions as identified by IEP. The Yolo Bypass has been identified as a high restoration priority by the National Marine Fisheries Service and US Fish and Wildlife Service Biological Opinions for Delta Smelt, Winter and Spring-run Chinook salmon and by California EcoRestore. The YBFMP informs the restoration actions that are mandated or recommended in these plans and provides critical baseline data on the ecology of the bypass and how it interacts with the broader San Francisco Estuary. Program objectives include: Collecting baseline data on water quality, chlorophyll, lower trophic level biota, and fish in the Yolo Bypass to monitor spatial and temporal changes in trends and abundance; Analyzing and communicating Yolo Bypass data with stakeholders and the scientific and management communities to address pertinent management related questions; Providing technical expertise on Yolo Bypass aquatic ecology and monitoring and sampling methods. We collect discrete water quality data using a YSI ProDSS and sample phytoplankton, chlorophyll and nutrients as discrete water grabs taken biweekly (or weekly during Yolo Bypass inundation) along with lower trophic tows. Water is sampled at three sites along the Yolo Bypass and Sacramento River, then processed and analyzed by an internal DWR laboratory.

The Yolo Bypass Fish Monitoring Program (YBFMP) operates a rotary screw trap and fyke trap and conducts biweekly beach seine and lower trophic surveys in addition to maintaining water quality instrumentation in the bypass. The YBFMP serves to fill information gaps regarding environmental conditions in the bypass that trigger migrations and enhanced survival and growth of native fishes, as well as provide data for IEP synthesis efforts. YBFMP staff also conduct analyses of YBFMP monitoring data to address pertinent management related questions as identified by IEP. The Yolo Bypass has been identified as a high restoration priority by the National Marine Fisheries Service and US Fish and Wildlife Service Biological Opinions for Delta Smelt, Winter and Spring-run Chinook salmon and by California EcoRestore. The YBFMP informs the restoration actions that are mandated or recommended in these plans and provides critical baseline data on the ecology of the bypass and how it interacts with the broader San Francisco Estuary. Program objectives include: Collecting baseline data on water quality, chlorophyll, lower trophic level biota, and fish in the Yolo Bypass to monitor spatial and temporal changes in trends and abundance; Analyzing and communicating Yolo Bypass data with stakeholders and the scientific and management communities to address pertinent management related questions; Providing technical expertise on Yolo Bypass aquatic ecology and monitoring and sampling methods. We collect discrete water quality data using a YSI ProDSS and sample phytoplankton, chlorophyll and nutrients as discrete water grabs taken biweekly (or weekly during Yolo Bypass inundation) along with lower trophic tows. Water is sampled at three sites along the Yolo Bypass and Sacramento River, then processed and analyzed by an internal DWR laboratory.