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A Delta Renewed: A Guide to Science-Based Ecological Restoration in the Sacramento-San Joaquin Delta

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A Delta Renewed: A Guide to Science-Based Ecological Restoration in the Sacramento-San Joaquin Delta
San Francisco Estuary Institute (SFEI) | November 1, 2016...
Summary
A Delta Renewed and the larger Delta Landscapes project are part of an ongoing effort to address these critically important challenges. They provide guidance...
A Delta Renewed and the larger Delta Landscapes project are part of an ongoing effort to address these critically important challenges. They provide guidance for restoration that renews critical functions over time without having major negative impacts on the current human enterprise in the Delta area and on other areas dependent on its services. The idea is to determine the most efficient ways to recover Delta functioning so that human benefits are maintained, while investing in process-based recovery of landscape functions. The scientists working on this project assume that this goal is best achieved if we can understand how the Delta functioned before major European modification. We can then use that knowledge as a guide to developing a diverse portfolio of habitats and connections that might sustain native species, and the attributes of a healthy Delta into the future. The effort to reconstruct the Delta of the early 1800s has been challenging, but is now completed. The next step is to devise management scenarios that will recover important functions and native species where possible. There is no intent to try to recreate the Delta of the past. That is impossible without sacrificing our objective of maintaining and even improving the human enterprises now present. What is essential now is to obtain general agreement among all of the stakeholders, which includes all citizens of California, that the Delta should be managed for the benefit of people and wildlife in a sustainable way. Given the uncertainties inherent in any large-scale reconciliation effort, there is a real need to appreciate the complex interactions and inter-dependencies that characterize the various components of the Delta landscape. There is also a need to understand the uncertainties of future climate change and to recognize the diversity of needs among our fellow citizens. Our hopes for success will ultimately depend on generating a spirit of cooperation for the common good. It won’t be easy, but the stakes are high. The Delta Landscapes project is dedicated to that goal.

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A Menu of Fire Response Water Quality Monitoring Options and Recommendations for Water Year 2019 and Beyond

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A Menu of Fire Response Water Quality Monitoring Options and Recommendations for Water Year 2019 and Beyond
San Francisco Estuary Institute (SFEI) | July 2, 2018...
Summary
In October 2017, the Tubbs Fire and the Nuns Fire burned 93,400 acres of the Mark West Creek and Santa Rosa Creek watersheds,...
In October 2017, the Tubbs Fire and the Nuns Fire burned 93,400 acres of the Mark West Creek and Santa Rosa Creek watersheds, killing 22 people, and incinerating approximately 7,000 structures. After the fires, many agencies worked together to deploy water and sediment related best management practices (BMPs) in the burn area (e.g., waddles, emergency hydroseeding, and filter systems on storm drains) and worked on removing contaminated debris and soil from burned properties. The City of Santa Rosa conducted water quality sampling to verify that the BMPs were working. Water quality samples were collected at selected sites before and after flow interacted with the BMP; the City was generally pleased with the results. Subsequently, the North Coast Regional Water Quality Control Board (Water Board) developed a preliminary monitoring design for WY 2018 to measure potential water quality impacts of the fires in relation to beneficial uses. Selected streams were sampled for parameters that could be compared to regulatory water quality criteria. The attachment contains a summary of the results for WY 2018. Based on this initial dataset, the apparent early success of the BMP program, and the soil clean-ups that have occurred, the focus going forward should be on monitoring larger-scale and longer-term impacts. This document outlines monitoring options for consideration for WY 2019 and beyond for four categories: Water Chemistry, Hydromodification, Geomorphic Response, and Ecology.

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A Rapid Assessment Method to Identify Potential Groundwater Flooding Hotspots as Sea Levels Rise in Coastal Cities

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A Rapid Assessment Method to Identify Potential Groundwater Flooding Hotspots as Sea Levels Rise in Coastal Cities
Water, Multidisciplinary Digital Publishing Institute (MDPI) | October 25, 2019...
Summary
Sea level rise (SLR) will cause shallow unconfined coastal aquifers to rise. Rising groundwater can emerge as surface flooding and impact buried infrastructure, soil...
Sea level rise (SLR) will cause shallow unconfined coastal aquifers to rise. Rising groundwater can emerge as surface flooding and impact buried infrastructure, soil behavior, human health, and nearshore ecosystems. Higher groundwater can also reduce infiltration rates for stormwater, adding to surface flooding problems. Levees and seawalls may not prevent these impacts. Pumping may accelerate land subsidence rates, thereby exacerbating flooding problems associated with SLR. Public agencies at all jurisdiction levels will need information regarding where groundwater impacts are likely to occur for development and infrastructure planning, as extreme precipitation events combine with SLR to drive more frequent flooding. We used empirical depth-to-water data and a digital elevation model of the San Francisco Bay Area to construct an interpolated surface of estimated minimum depth-to-water for 489 square kilometers along the San Francisco Bay shoreline. This rapid assessment approach identified key locations where more rigorous data collection and dynamic modeling is needed to identify risks and prevent impacts to health, buildings, and infrastructure, and develop adaptation strategies for SLR.

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Alternative Flame Retardants in San Francisco Bay: Synthesis and Strategy

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Alternative Flame Retardants in San Francisco Bay: Synthesis and Strategy
San Francisco Estuary Institute (SFEI) | September 3, 2018...
Summary
The RMP Small Tributaries Loading Strategy (STLS) Team and the Sources, Pathways and Loadings Workgroup (SPLWG) developed and funded a $13,000 special study...
The RMP Small Tributaries Loading Strategy (STLS) Team and the Sources, Pathways and Loadings Workgroup (SPLWG) developed and funded a $13,000 special study in 2018 to review available data and previously developed conceptual models for polybrominated diphenyl ethers (PBDEs) to support a stormwater-related alternative flame retardants conceptual model. This technical report summarizes the results of the study.

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Assessing the effectiveness of drywells as tools for stormwater management and aquifer recharge and their groundwater contamination potential
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Assessing the effectiveness of drywells as tools for stormwater management and aquifer recharge and their groundwater contamination potential
Science Direct | May 24, 2016...
Summary
Drywells are gravity-fed, excavated pits with perforated casings used to facilitate stormwater infiltration and groundwater recharge in areas where drainage and diversion of...
Drywells are gravity-fed, excavated pits with perforated casings used to facilitate stormwater infiltration and groundwater recharge in areas where drainage and diversion of storm flows is problematic. Historically, drywells have predominantly been used as a form of stormwater management in locations that receive high volumes of precipitation; however the use of drywells is increasingly being evaluated as a method to supplement groundwater recharge, especially in areas facing severe drought.

Studies have shown that drywells can be an effective means to increase recharge to aquifers; however, the potential for groundwater contamination caused by polluted stormwater runoff bypassing transport through surface soil and near surface sediment has prevented more widespread use of drywells as a recharge mechanism. Numerous studies have shown that groundwater and drinking water contamination from drywells can be avoided if drywells are used in appropriate locations and properly maintained.

The effectiveness of drywells for aquifer recharge depends on the hydrogeologic setting and land use surrounding a site, as well as influent stormwater quantity and quality. These parameters may be informed for a specific drywell site through geologic and hydrologic characterization and adequate monitoring of stormwater and groundwater quality.

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Bay Area Green Infrastructure Water Quality Synthesis

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Bay Area Green Infrastructure Water Quality Synthesis
San Francisco Estuary Institute (SFEI) / Aquatic Science Center (ASC) | June 1, 2018...
Summary
San Francisco Bay is impacted by the numerous urban pollutants that flow from the surrounding landscape during storm events. In San Francisco Bay, total...
San Francisco Bay is impacted by the numerous urban pollutants that flow from the surrounding landscape during storm events. In San Francisco Bay, total maximum daily load (TMDL) clean-up plans are in place for polychlorinated biphenyls (PCBs) and mercury (Hg) (Davis et al., 2007; Davis et al., 2012).

As municipalities strive to reach regulatory targets, green infrastructure (GI) presents a promising solution for managing stormwater pollutants while achieving additional environmental and social benefits. However, remaining data gaps including the best design layout, media composition, and vegetation and submerged zone effects on performance can prevent local managers from accurately assessing water quality benefits provided by green infrastructure as well as the maintenance needs to sustain adequate performance.

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Benefit Accounting of Nature-Based Solutions for Watersheds

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Benefit Accounting of Nature-Based Solutions for Watersheds
Pacific Institute | March 1, 2021...
Summary
Nature-based solutions (NBS) have the potential to combat pressing global problems, including climate change, water security and biodiversity loss. This guide builds on Benefit...
Nature-based solutions (NBS) have the potential to combat pressing global problems, including climate change, water security and biodiversity loss. This guide builds on Benefit Accounting of Nature-Based Solutions for Watersheds Landscape Assessment (Shiao et al., 2020), which highlights the barriers for businesses to implement NBS at a large scale. The primary challenge for corporations is that there is no standardized method to identify, estimate and monitor the benefits that NBS can provide, making it hard to build the case for investments in these solutions.

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Building Ecological Resilience in Highly Modified Landscapes

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Building Ecological Resilience in Highly Modified Landscapes
BioScience | November 7, 2018...
Summary
Ecological resilience is a powerful heuristic for ecosystem management in the context of rapid environmental change. Significant efforts are underway to improve the...

Ecological resilience is a powerful heuristic for ecosystem management in the context of rapid environmental change. Significant efforts are underway to improve the resilience of biodiversity and ecological function to extreme events and directional change across all types of landscapes, from intact natural systems to highly modified landscapes such as cities and agricultural regions. However, identifying management strategies likely to promote ecological resilience remains a challenge. In this article, we present seven core dimensions to guide long-term and large-scale resilience planning in highly modified landscapes, with the objective of providing a structure and shared vocabulary for recognizing opportunities and actions likely to increase resilience across the whole landscape. We illustrate application of our approach to landscape-scale ecosystem management through case studies from two highly modified California landscapes, Silicon Valley and the Sacramento–San Joaquin Delta. We propose that resilience-based management is best implemented at large spatial scales and through collaborative, cross-sector partnerships.

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Clean Water, Clean Beaches Water Quality Funding Measure*

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Clean Water, Clean Beaches Water Quality Funding Measure*
Los Angeles County Department of Public Works, Los Angeles County Flood Control District | September 21, 2012...
Summary
The Problem: Stormwater and runoff rushes down the street, picking up trash and toxic pollutants. On a rainy day, over 10 billion gallons...

The Problem: Stormwater and runoff rushes down the street, picking up trash and toxic pollutants. On a rainy day, over 10 billion gallons of contaminated stormwater flows directly — untreated — into rivers, creeks, lakes and our bay and coastal waters. Polluted stormwater and urban runoff include toxins and pathogens that can affect our health, drinking water supplies, and the health of marine life. Contaminants include: Industrial solvents, paints and chemicals; heavy metals like lead, mercury, chromium and arsenic; infection-causing bacteria; pesticides and fertilizers; and trash like plastics, cigarette butts, candy wrappers and syringes.

*The proposed solution, a parcel tax to fund stormwater remediation and capture projects, failed before the Los Angeles County Board of Supervisors in 2013.

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Climate warming enhancement of catastrophic southern California debris flows

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Climate warming enhancement of catastrophic southern California debris flows
Nature | June 29, 2020...
Summary
The sequence of wildfires followed by debris flows, frequently affects southern California, reflecting its drought-heavy precipitation climate bipolarity. Organic debris from incomplete burning...
The sequence of wildfires followed by debris flows, frequently affects southern California, reflecting its drought-heavy precipitation climate bipolarity. Organic debris from incomplete burning is lighter than inorganic matter, and partially inviscid. Hence lower rainfall totals can trigger downslope motion than typically required by the underlying clasts of loose inorganic granular material. After advection downslope, the pebble-laden organic debris has a higher capacity for rilling; a positive feedback process. A mechanism is proposed whereby boulders are ‘rafted’ by organic debris. This coordinated movement of boulders greatly enhances the debris flow erosion capacity. This climate change sensitive debris flow enhancing mechanism, through organic–inorganic granular material interaction, is supported by observations and the numerical simulations. Using a model explicitly parameterizing erosion processes, including runoff entrainment, rilling incision, and bank collapse, the lifecycle of the Montecito debris flow of January 9, 2018 is simulated, providing quantitative estimates of mass conveyed and debris sorting at the terminus. Peak rafting speeds are ~ 12.9 m/s at ~ 300 m asl. Total boulder (effective diameter > 25 cm) volume involved for the Ysidro Creek area alone is ~ 5 × 10⁴ m³, scattered between the region 50–260 m asl. Debris flows are highly repeatable and locations prone to debris flows are identified and their likelihood of realization estimated.

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