water quality

South Bay Salt Pond Waterbird Surveys, September 2021 – May 2022

ariela — Wed, 19 Feb 2025 19:40:41 +0000

South Bay Salt Pond Waterbird Surveys, September 2021 – May 2022 ariela Wed, 02/19/2025 - 11:40

Document Category

Scientific Reports

Author(s)

Gabbie Burns

SFBBO

Date

2022-10

Summary

FINAL REPORT

Suggested citation: Burns, G. 2022. South Bay Salt Pond Waterbird Surveys: September – May 2022. Report prepared for the South Bay Salt Pond Restoration Project.

Executive Summary
This report serves as a data summary and coarse-scale assessment of waterbird and water quality monitoring efforts at six pond complexes in the South San Francisco Bay. Coyote Hills, Dumbarton, and Mowry salt ponds are owned by Don Edwards San Francisco Bay National Wildlife Refuge and managed for salt production by Cargill Salt. Alviso and Ravenswood complexes are owned and managed by Don Edwards San Francisco Bay National Wildlife Refuge. Eden Landing Ecological Reserve (Eden Landing) ponds are owned and managed by California Department of Fish and Wildlife (CDFW), with the exception pond CP3C, which is owned by Cargill Salt. This report is based primarily on data collected by the San Francisco Bay Bird Observatory between September 2021 and May 2022.

From September 2021 – May 2022, we conducted waterbird surveys and water quality sampling at 82 ponds (22 Cargill-managed salt production ponds and 60 SBSPRP managed ponds). We examined species richness, abundance, and behavior of waterbird assemblages within and among pond complexes. We grouped species into guilds (e.g., dabbling ducks, diving ducks, gulls) based on foraging methods and prey requirements to understand waterbird use of these ponds. We also put these waterbird counts in the context of long-term trends to assess changes in waterbird numbers relative to baseline counts from before marsh restoration.

We recorded 1,248,069 waterbird observations of 78 species (all sites combined). The Alviso and Eden Landing pond complexes supported the greatest species diversity and Alviso had the highest abundances of all complexes. The abundance of 6 out of 10 species/guilds has increased in SBSPRP ponds since prior to restoration activities in 2005 – 2007. Exceptions comprise phalaropes, Bonaparte’s gulls, dabbling ducks, medium shorebirds. Bonaparte’s gull counts declined by 84% which exceeds the threshold of a 50% decline in a single year.

As the SBSPRP progresses, we recommend a precautionary approach to waterbird management and tidal marsh restoration and maintenance of enough of the ponds within the project footprint to provide a variety of salinity and water levels suitable for many different guilds. Special consideration should be given to birds that traditionally prefer medium to high salinity ponds, such as phalaropes and Eared Grebes, since restoration activities have already reduced the prevalence of these habitat conditions and the remaining high salinity habitat is managed for salt production rather than waterbird needs. Creating or maintaining islands or undisturbed levees will provide additional nesting and roosting habitat for other guilds. As the restoration advances, continued monitoring of avian use of Cargill-managed and SBSPRP ponds will be valuable in assessing progress toward the management target of maintaining baseline waterbird numbers.

However, a regional perspective will be needed to tease apart drivers of waterbird use in the project area. With more than a decade of bird and water quality monitoring data available, a useful next step will be to model bird habitat use and to use the model to predict the impact of future restoration scenarios on bird abundance.

Keywords

Pond Complex

Alviso

Eden Landing

Ravenswood

South Bay Salt Pond Waterbird Surveys, September 2019 – February 2021

ariela — Wed, 19 Feb 2025 19:26:38 +0000

South Bay Salt Pond Waterbird Surveys, September 2019 – February 2021 ariela Wed, 02/19/2025 - 11:26

Document Category

Scientific Reports

Author(s)

Max Tarjan

Gabbie Burns

SFBBO

Date

2021-06

Summary

EXECUTIVE SUMMARY
This report serves as a data summary and coarse-scale assessment of waterbird and water quality monitoring efforts at six pond complexes in the South San Francisco Bay. Coyote Hills, Dumbarton, and Mowry salt ponds are owned by Don Edwards San Francisco Bay National Wildlife Refuge and managed for salt production by Cargill Salt. Alviso and Ravenswood complexes are owned and managed by Don Edwards San Francisco Bay National Wildlife Refuge. Eden Landing Ecological Reserve (Eden Landing) ponds are owned and managed by California Department of Fish and Wildlife (CDFW), with the exception pond CP3C, which is owned by Cargill Salt. This report is based primarily on data collected by the San Francisco Bay Bird Observatory between September 2019 and February 2021.

From September 2019 to February 2020, we conducted waterbird surveys and water quality sampling at 82 ponds (22 Cargill-managed salt production ponds and 60 SBSPRP managed ponds). Due to site access limitations associated with the COVID-19 pandemic, we surveyed 45 ponds across multiple complexes from March to April 11, 2020 and 25 ponds within Eden Landing Ecological Reserve from April 15 to May 2020 and December 2020 to February 2021. We examined species richness, abundance, and behavior of waterbird assemblages within and among pond complexes. We grouped species into guilds (e.g., dabbling ducks, diving ducks, gulls) based on foraging methods and prey requirements to understand waterbird use of these ponds. We also put these waterbird counts in the context of long-term trends to assess changes in waterbird numbers relative to baseline counts from before marsh restoration. We recorded 1,293,322 waterbird observations of 78 species (all sites combined). The Alviso and Eden Landing pond complexes supported the greatest species diversity and also the highest abundances of all complexes. The abundances of diving ducks, Ruddy ducks, dabbling ducks, and medium shorebirds in winter, as well as small shorebirds in fall and Least Terns in summer have increased in SBSPRP ponds since prior to restoration activities in 2005–2007. Counts of small shorebirds in spring remain at baseline values. Eared Grebes have increased in active salt production ponds (Coyote Hills, Dumbarton, and Mowry complexes), but not in SBSPRP ponds (Alviso, Eden Landing, and Ravenswood complexes), and Bonaparte’s gulls have declined by 18%. Since limited ponds were surveyed in 2020, meaningful comparisons to previous years’ data were restricted to a subset of sites in spring and winter. Further, no fall surveys were completed in 2020. While the results presented in this report are informative, a complete understanding of contemporary waterbird trends in the project area will require resumption of surveys at all sites in fall, winter, and spring of 2021-2022.

Phalarope migration surveys in 2020 found that counts of Wilson’s phalaropes peaked at 767 phalaropes on July 21 and counts of Red-necked phalaropes peaked at 1,700 phalaropes on August 28. The peak count of Red-necked phalaropes was higher than in 2019 (1,447 phalaropes), despite visiting fewer ponds in 2020.

As the SBSPRP progresses, we recommend a precautionary approach to waterbird management and tidal marsh restoration and maintenance of enough of the ponds within the project footprint to provide a variety of salinity and water levels suitable for many different guilds. Special consideration should be given to birds that prefer medium to high salinity ponds, such as phalaropes and Eared Grebes, since restoration activities have already reduced the prevalence of these habitat conditions and the remaining high salinity habitat is managed for salt production rather than waterbird needs. Creating or maintaining islands or undisturbed levees will provide additional nesting and roosting habitat for other guilds. As the restoration advances, continued monitoring of avian use of Cargill-managed and SBSPRP ponds will be valuable in assessing progress toward the management target of maintaining baseline waterbird numbers. However, a regional perspective will be needed to tease apart drivers of waterbird use in the project area. With more than a decade of bird and water quality monitoring data available, a useful next step will be to model bird habitat use and to use the model to predict the impact of future restoration scenarios on bird abundance.

Keywords

Pond Complex

Alviso

Eden Landing

Ravenswood

South Bay Salt Pond Waterbird Surveys, September 2022 – May 2023

ariela — Wed, 19 Feb 2025 19:04:36 +0000

South Bay Salt Pond Waterbird Surveys, September 2022 – May 2023 ariela Wed, 02/19/2025 - 11:04

Document Category

Scientific Reports

Author(s)

Nathan Van Schmidt

SFBBO

Date

2023-10

Summary

REVISED FINAL REPORT

Suggested citation: Van Schmidt, Nathan D. 2023. South Bay Salt Pond Waterbird Surveys: September 2022–May 2023. Report prepared for the South Bay Salt Pond Restoration Project.

Executive Summary
This report serves as a data summary and coarse-scale assessment of waterbird and water quality monitoring efforts at six pond complexes in the South San Francisco Bay. Coyote Hills, Dumbarton, and Mowry salt ponds are owned by Don Edwards San Francisco Bay National Wildlife Refuge and managed for salt production by Cargill Salt. Alviso and Ravenswood complexes are owned and managed by the U.S. Fish & Wildlife Service as part of the Don Edwards San Francisco Bay National Wildlife Refuge. Eden Landing Ecological Reserve (Eden Landing) ponds are owned and managed by California Department of Fish and Wildlife, with the exception pond CP3C, which is owned by Cargill Salt. This report is based primarily on data collected by the San Francisco Bay Bird Observatory between September 2022 and May 2023.

The purpose of this ongoing study is to describe avian use of ponds to guide regional waterbird conservation, management, and habitat restoration efforts. The South Bay Salt Pond Restoration Project (SBSPRP) is restoring 15,000 acres of former salt evaporation ponds to a mix of tidal marsh and enhanced managed pond habitats. Restoration and monitoring is entering its third decade, and long-term population analyses have shown declines in some species and guilds, but evidence of cyclical trends (regular increases and decreases) in others, which may be driven by climate patterns or density-dependent regulation. It is therefore important to determine the drivers of these long-term trends, and to contextualize local trends with population trends elsewhere in the range, to assess the likelihood that observed declines are driven by SBSPRP actions rather than other factors. Understanding how waterbirds use ponds, identifying key habitat associations, and incorporating features essential to pond-dependent species into restoration plans is important for helping maintain baseline numbers of waterbirds in the South Bay and recovering populations that have experienced long-term declines.

From September 2022 – May 2023, we conducted waterbird surveys and water quality sampling at 82 ponds (22 Cargill-managed salt production ponds and 60 SBSPRP-managed ponds). We examined species richness, abundance, and behavior of waterbird assemblages within and among pond complexes. We grouped species into guilds (e.g., dabbling ducks, diving ducks, gulls) based on foraging methods and prey requirements to understand waterbird use of these ponds. We used these data to assess long-term changes in waterbird numbers relative to baseline counts from before marsh restoration. We recorded 1,246,072 waterbird observations of 82 species (all sites combined). The Alviso and Eden Landing pond complexes supported the greatest species diversity and Alviso had the highest abundances of all complexes. The abundance of 5 out of 7 currently tracked species/guilds has increased in SBSPRP ponds since prior to restoration activities in 2005–2007 (6 of 8, if counting small shorebirds in both the fall and spring). Exceptions comprise Bonaparte's gulls, dabbling ducks, and medium shorebirds; plus phalaropes, which supplemental summer surveys show have declined. For most of the species/guilds that increased in abundance across all ponds, the increases are largely due to higher counts within the SBSPRP area. This indicates long-term benefits of the project for many waterbird populations within South San Francisco Bay. However, 6 of the currently tracked fall/winter/spring taxa have declined in recent years, which is cause for caution. Only small shorebirds are currently stable (slightly increasing in fall and slightly declining in spring).

Two species/guilds have declined below trigger values defined in the Adaptive Management Plan: Bonaparte’s gulls and phalaropes. In the previous year, Bonaparte’s gull had declined by 84% relative to their baseline abundance, crossing the adaptive management plan’s trigger threshold of >50% decline below the baseline in a single year, or >25% in three consecutive years. This winter, detections of Bonaparte’s gull had increased from the previous year to an average of 763, but this still represents a decline of -40% and the running average two-year decline is -62% (winter 2021 and 2022 seasons; winter 2020 was not surveyed due to COVID-19 restrictions).

Given that two other saline specialist guilds also show signs of decline within the SBSPRP area–phalaropes have passed the trigger level, and eared grebes remain in salt production ponds but have dwindled in the SBSPRP footprint–the loss of high-salinity habitats is likely one of the causative factors. We recommend special consideration should be given to habitat needs of phalaropes and Bonaparte’s gulls, but note that these are poorly understood within the South San Francisco Bay ecosystem. More focused field studies on their habitat use and selection are needed to identify their habitat requirements and understand how to manage them effectively to recover these populations. In the meantime, we recommend cautiously maintaining a variety of water quality parameter levels in order to support guilds with different habitat requirements.

Keywords

Pond Complex

Alviso

Eden Landing

Ravenswood

Continuous Suspended Sediment Monitoring in South and Lower South San Francisco Bay: Year Two (2023) Report

ariela — Thu, 08 Aug 2024 16:56:03 +0000

Continuous Suspended Sediment Monitoring in South and Lower South San Francisco Bay: Year Two (2023) Report ariela Thu, 08/08/2024 - 09:56

Document Category

Scientific Reports

Author(s)

San Francisco Estuary Institute

Date

2024-07

Summary

Executive Summary
This report provides a project update for year two of a three-year collaboration between the San
Francisco Bay Nutrient Management Strategy (NMS), San Francisco Bay Regional Monitoring Program,
and South Bay Salt Pond Restoration Project, to estimate high frequency suspended sediment
concentration (SSC) in San Francisco Bay (SFB). Through its role in monitoring water quality in SFB, the
NMS maintains an array of autonomous sondes that record high frequency (15-minute) water column
turbidity, amongst a suite of other environmental parameters. Turbidity data from these monitoring
sites was combined with discrete SSC samples to create a bay-wide turbidity-SSC calibration, allowing
for estimates of high frequency SSC. The calibration for 7 of these sites was performed using a linear
mixed effect model (LMM), which leverages similarities in the turbidity-SSC relationship between sites
while allowing for potential differences. An additional turbidity-only sensor was deployed at an 8th site
along with discrete SSC collection, with this calibration performed via least squares linear
regression. Both models showed reasonable agreement between turbidity and SSC, with R2 = 0.62 for
the LMM, and R2 = 0.72 for the regression performed at the turbidity-only site.
Using these calibrations, we created continuous 15-min SSC datasets at all 8 locations, representing 1
channel, 4 shoal, and 3 slough sites. These calibrations are considered preliminary and will be finalized
as part of the final year 3 report after SSC sample collection is completed. For these datasets, only
turbidity data less than 110% of the maximum calibration value were converted to SSC. In total, SSC
estimates were generated for ~90-99% of the data record at the water quality monitoring sites and 68%
of the record at the turbidity-only station.

This work was funded by the South Bay Salt Pond Restoration Project, the Regional Monitoring Program
for Water Quality in San Francisco Bay, and the San Francisco Bay Nutrient Management Strategy.

Suggested citation:
Mourier, L.; Montgomery, L.; Volaric, M.; Chelsky, A.; Senn, D. 2024. Continuous Suspended Sediment
Monitoring in South and Lower South San Francisco Bay: Year Two (2023) Report. SFEI Contribution No.
1188. San Francisco Estuary Institute: Richmond, CA

Keywords

Pond Complex

Alviso

Eden Landing

Ravenswood

2023 Self-Monitoring Report Eden Landing Ecological Reserve

Dave Halsing — Sat, 02 Mar 2024 01:14:29 +0000

2023 Self-Monitoring Report Eden Landing Ecological Reserve Dave Halsing Fri, 03/01/2024 - 17:14

Document Category

Monitoring Reports

Author(s)

Carly White

Date

March 1, 2024

Summary

2023 Self-Monitoring Report prepared for CDFW's Baumberg Complex/Eden Landing Ecological Reserve in compliance with the San Francisco Bay Regional Water Quality Control Board.

Keywords

monitoring

water quality

Pond Complex

Eden Landing

Self-Monitoring Report - Don Edwards San Francisco Bay National Wildlife Refuge - 2022

ariela — Wed, 31 May 2023 20:07:02 +0000

Self-Monitoring Report - Don Edwards San Francisco Bay National Wildlife Refuge - 2022 ariela Wed, 05/31/2023 - 13:07

Document Category

Scientific Reports

Author(s)

USFWS

Date

2023-03

Summary

Introduction
The South Bay Salt Pond Restoration Project (Project) 2022 Annual Self-monitoring Report on Water Quality has been prepared to provide an overview of the Projects effects on water quality and habitat suitability of managed ponds due to management and restoration activities. This report includes: 1) Water quality results from the U.S. Fish and Wildlife Service (Service) Site Specific Protocol for Monitoring of South Bay Ponds (in draft), 2) A summary of the Project’s Phase 2 progress during 2022 and 3) A summary of 2022 Refuge Operations and Maintenance activities, and 4) Update on research happening on managed ponds.

This annual report is designed to meet California Regional Water Quality Control Board (RWQCB) permitting requirements for a water quality self-monitoring plan as described in R2-2018-0020, Findings 9, & 111-113, as well as South Bay Salt Pond Restoration Project Phase 2 Monitoring Plan and Water Quality Self-monitoring Program for Refuge Lands (C. Strong & Underwood 2018), which was prepared as part of the compliance with RWQCB’s permitting requirements. This Report will also be submitted to NOAA’s National Marine Fisheries Service (NMFS) per the Project’s Phase 2 Biological Opinion, WCR-2017-6803.

It is anticipated that both water quality and fisheries information will help the RWQCB and NMFS: 1) understand the status of the Project; 2) provide feedback and guidance to the Project Management Team on current and future applied studies and monitoring; and 3) assist in identifying emerging key uncertainties and management decisions required to keep the Project on track toward its restoration objectives as we implement Phase 2.

Keywords

monitoring

water quality

fish

Pond Complex

Alviso

Ravenswood

South San Francisco Bay Salt Pond Restoration Project—A Synthesis of Phase-1 Mercury Studies

ariela — Wed, 15 Mar 2023 01:38:40 +0000

South San Francisco Bay Salt Pond Restoration Project—A Synthesis of Phase-1 Mercury Studies

Cover of publication

ariela Tue, 03/14/2023 - 18:38

Document Category

Scientific Reports

Author(s)

Mark Marvin-DiPasquale

Darrel Slotton

Joshua T. Ackerman

Maureen A. Downing-Kunz

Date

2023-03

Summary

Abstract

The South Bay Salt Pond Restoration Project (SBSPRP) encompasses over 6,000 hectares of former salt production ponds along the south edge of the San Francisco Bay and represents the largest wetland restoration effort on the west coast of North America. A series of studies associated with Phase 1 (2010–2018) restoration activities that are focused on a historically mercury contaminated slough and series of ponds within the restoration area have recently been completed.

This report brings together the key findings of these loosely coordinated studies and integrates the results into a more comprehensive and holistic product that informs future restoration activities associated with the SBSPRP and elsewhere. This report documents key findings associated with the breach of pond A6: (1) a short-term spike in slough fish (Mississippi silverside) total mercury concentration in lower Alviso Slough; (2) a short-term spike in surface-water particulate total mercury in lower Alviso Slough; (3) significant sediment scour in Alviso Slough adjacent to and downstream of the breach points; (4) a decrease in surface-sediment methylmercury (as a percentage of total mercury) in lower Alviso Slough; (5) the transport of 70 kilograms per year of sediment-associated total mercury into pond A6 during the first 2 years following the breach but with much of this coming from outside of Alviso Slough, presumably from the nearby shallows, Guadalupe Slough, and the larger southern San Francisco Bay area; and (6) a slowing of bed sediment erosion in lower Alviso Slough 3–5 years after the breaching of pond A6.

Although this report is not intended to be prescriptive in terms of the next steps the SBSPRP should or should not take, the totality of the findings presented provide critical process-level information regarding the extent and the duration of spikes in mercury levels in water, sediment, fish, and birds, which appeared to result from the two management actions under study. Thus, these results can be used to anticipate similar ecosystem responses associated with similar management actions that may be considered in the future. We also conclude this report by highlighting unanswered questions associated with mercury dynamics as it relates to the restoration project, and possible future directions for research.

Suggested Citation

Marvin-DiPasquale, M., Slotton, D., Ackerman, J.T., Downing-Kunz, M., Jaffe, B.E., Foxgrover, A.C., Achete, F., and van der Wegen, M., 2022, South San Francisco Bay Salt Pond Restoration Project—A synthesis of Phase-1 mercury studies, U.S. Geological Survey Scientific Investigations Report 2022-5113, 147 p., https://doi.org/10.3133/sir20225113.

First posted March 7, 2023

For additional information, contact:

Director,
Water Resources, Earth System Processes Division
U.S. Geological Survey
345 Middlefield Road
Menlo Park, California, 94025

Keywords

Pond Complex

Alviso

Eden Landing

Ravenswood

Content available here

USGS Publications Warehouse: South San Francisco Bay Salt Pond Restoration Proj…

2022 Annual Self-Monitoring Report - Don Edwards SF Bay National Wildlife Refuge

ariela — Wed, 15 Mar 2023 00:59:56 +0000

2022 Annual Self-Monitoring Report - Don Edwards SF Bay National Wildlife Refuge ariela Tue, 03/14/2023 - 17:59

Document Category

Monitoring Reports

Author(s)

USFWS

Date

2023-03-01

Keywords

monitoring

water quality

fish

Pond Complex

Alviso

Ravenswood

South Bay Salt Ponds Restoration Project Final Data Acquisition Plan

admin — Thu, 23 Nov 2017 00:21:53 +0000

South Bay Salt Ponds Restoration Project Final Data Acquisition Plan admin Wed, 11/22/2017 - 16:21

Document Category

Scientific Reports

Author(s)

H.T. Harvey & Associates

Date

2004-03-25

Keywords

birds

fish

habitat evolution

trail use/public access

Mercury speciation and other constituent data for surface sediment and water associated with the South San Francisco Bay Salt Pond Restoration, 2010-18

Dave Halsing — Sat, 09 Jul 2022 01:47:51 +0000

Mercury speciation and other constituent data for surface sediment and water associated with the South San Francisco Bay Salt Pond Restoration, 2010-18 Dave Halsing Fri, 07/08/2022 - 18:47

Document Category

Scientific Reports

Author(s)

Mark Marvin-DiPasquale

Jennifer L. Agee

Le Kieu

Evangelos Kakouros

Date

2019-05-06

Summary

This dataset includes mercury and other constituent concentration and physical properties data for surface sediment, pore water and surface water collected as part of the South San Francisco Bay Salt Pond Restoration Phase 1 (2010 to 2018) studies. The overarching focus of these studies was to monitor mercury (Hg) biogeochemistry in both sediment and water in response to management actions associated with the conversion of former salt producing ponds to contemporary wetland habitat.

Keywords

mercury

water quality

Pond Complex

Alviso

Content available here

https://www.sciencebase.gov/catalog/item/5b68c246e4b006a11f75b90b