Adaptation of a reference site selection methodology to creeks and sloughs of California’s Sacramento Valley and alternative strategies for developing a regional bioassessment framework

Central Valley Regional Water Quality Control Board (CVRWQCB) | November 14th, 2005

Bioassessment has shown significant promise as an effective tool for ambient water quality management in many regions of California. However, the scale and intensity of l

Bioassessment has shown significant promise as an effective tool for ambient water quality management in many regions of California. However, the scale and intensity of landscape and water transport alteration in the Central Valley pose substantial challenges to implementing bioassessment to its full potential in the region. Bioassessment programs usually are established around a careful characterization of regional reference conditions, which can be defined as the condition of waterbodies that are least impaired by human activities. The reference condition defines a benchmark against which to infer biological impairment and to set expectations for biotic condition. Although there are several techniques available for determining reference condition, by far the most commonly applied is the use of reference sites, which are used to establish the range of natural variability in biotic condition. We investigated the potential for identifying reference sites for segments of sloughs and creeks of the Sacramento Valley at elevations less than 85 meters. We describe here the results of a pilot study designed to adapt an existing reference site selection methodology for use in the Central Valley. Potential reference sloughs and creeks were selected on the basis of a suite of visual assessments of riparian and instream condition and qualitative GIS-based land use data. Analysis of the benthic macroinvertebrate (BMI) assemblages collected from 30 targeted reference sites (23 creeks and 7 sloughs) was focused on addressing two main questions: 1) should creeks and sloughs be considered unique waterbody classes for the purposes of bioassessment?, 2) what is the potential for reference site based bioassessment in valley waterbodies? We addressed these questions with the BMI data using a combination of direct metric comparisons and NMS ordination. To improve our ability to interpret patterns at our 30 sites, we included two additional datasets of BMI data recently collected from nearby waterbodies. We drew three general conclusions from this study: 1) the adaptation of reference site selection to Central Valley streams was effective; we were able to find sites in the valley to use as reference and there is enough diversity in the BMI assemblages at these reference sites to use them to detect impairment, 2) although creeks and sloughs may need to be treated as separate classes of waterbodies for bioassessment-based regulation, there is evidence to suggest that the differences are not clear-cut and the question needs further investigation, 3) BMI assemblages in valley floor reference sites are clearly different from those in foothill reference sites. We discuss the potential for reference site based determination of reference conditions and summarize the current state of the science for defining reference condition in regions without adequate reference sites. We also list a set of recommendations that the Central Valley Regional Water Quality Control Board should consider while constructing a defensible framework for bioassessment in the Central Valley.

Adaptation Pathways: San Leandro Operational Landscape Unit

San Francisco Estuary Institute (SFEI) | May 15th, 2022

Given the diverse uses and conditions of San Francisco Bay’s 400-mile shoreline, a framework is needed to guide development of adaptation strategies appropriate to loca

Given the diverse uses and conditions of San Francisco Bay’s 400-mile shoreline, a framework is needed to guide development of adaptation strategies appropriate to local conditions. Operational Landscape Units (OLUs), outlined for the San Francisco Bay in the San Francisco Bay Shoreline Adaptation Atlas (SFEI and SPUR 2019), share common physical characteristics and therefore can benefit from being managed as individual units. OLUs cross traditional jurisdictional boundaries (cities, counties), and instead follow the boundaries of natural processes like tides, waves, and sediment movement. By planning at the OLU scale, it is possible to prioritize adaptation strategies that work synergistically. Coordinated OLU planning can help avoid unintended impacts on neighboring locales and identify synergies to make use of limited resources in a more efficient manner.

Adaptation Planning for the Bay Point Operational Landscape Unit

San Francisco Estuary Institute (SFEI) | April 15th, 2022

This document is not a vision or an adaptation plan, but rather is meant to catalyze discussion and offer resources around nature-based opportunities for SLR adaptation a

This document is not a vision or an adaptation plan, but rather is meant to catalyze discussion and offer resources around nature-based opportunities for SLR adaptation along Bay Point’s shoreline. The engagement and leadership of community-based stakeholders is key to the success of any adaptation planning effort, especially around issues as long-term and far-reaching as SLR and associated storm and tidal flooding. Without transparency and intentional community engagement throughout the planning process, opportunities for creative solutions will surely be missed and might lead to new problems or exacerbate existing ones disproportionately felt by low-income communities and communities of color. At the time this memo was written, there was not an active SLR adaptation working group or equivalent effort happening along the Bay Point shoreline. Consequently, the intent of this memo is to offer useful resources and ideas to support meaningful dialogue among stakeholders about shoreline adaptation planning. The Bay Point OLU study area is a mix of open space and developed areas at the mouth of the Sacramento and San Joaquin rivers, where the Delta meets the San Francisco Bay. The Bay Point OLU comprises unincorporated land known as Bay Point, a census-designated place within ContraCosta County, the City of Pittsburg, the spheres of influence of Pittsburg and Concord, and District V of Contra Costa County (Figure 2). Chapter 2 examines how Bay Point’s landscape has changed over time and Chapter 3 summarizes some of the vulnerability studies, habitat goals, and adaptation plans that have been developed for the study area. Chapter 4 offers more in-depth descriptions of the Bay Point OLU along with detailed maps that can be used to kick start SLR adaptation planning with a stakeholder working group along this reach of shoreline. Chapter 5 concludes with conceptual ideas that may be appropriate for different reaches of the shoreline, as a menu of possibilities to be further developed through a stakeholder process. Chapter 6 suggests ideas on next steps needed to move this work forward and offers a list of potential stakeholders as a starting place towards an adaptation working group to identify, evaluate, and prioritize adaptation strategies to manage flood risks along Bay Point’s shoreline.

Adaptation Strategies for Agricultural Sustainability in Yolo County, California

California Energy Commission (CEC) | July 31st, 2012

This place-based case study in an agricultural county in California’s Central Valley focused on the period of 2010–2050, and dealt with biophysical and socioeconomic

This place-based case study in an agricultural county in California’s Central Valley focused on the period of 2010–2050, and dealt with biophysical and socioeconomic issues related to both mitigation of greenhouse gas (GHG) emissions and to adaptation to an uncertain climate. In the past 100 years, changes in crop acreage has been more related to crop price and availability of irrigation water than to growing degree days during summer, and in fact, summer temperatures have increased less than winter temperatures. Econometric analysis indicated that warmer winters, as projected by Geophysical Fluid Dynamics Laboratory-Bias Corrected Constructed Analog during 2035–2050, could result in less wheat acreage, more alfalfa and tomato acreage, and slight effects on tree and vine crops. The Water Evaluation and Planning (WEAP) model showed that these econometric projections did not reduce irrigation demand under either the B1 or A2 scenarios, but a diverse, water-efficient cropping pattern combined with improved irrigation technology reduced demand to 12 percent below the historic mean. Collaboration during development of Yolo County’s Climate Action Plan showed that nitrous oxide (mainly from nitrogen fertilizers) was the main source (40 percent) of agricultural emissions. Emissions from cropland and rangeland were several orders of magnitude lower than urbanized land per unit area. A survey distributed to 570 farmers and ranchers achieved a 34 percent response rate. Farmers concerned about climate change were more likely to implement water conservation practices, and adopt voluntary GHG mitigation practices. Use of the urban growth model (UPlan) showed that channeling much or all future urban development into existing urban areas will increase ecosystem services by preserving agricultural land and open space, immensely reducing the Yolo County’s GHG emissions, and greatly enhancing agricultural sustainability.

Adapting California’s Water Management to Climate Change

Public Policy Institute of California (PPIC) | January 12th, 2009

Among the potential impacts of climate change, accelerated sea level rise and a reduced Sierra snowpack are the most certain. Both will pose significant challenges for wa

Among the potential impacts of climate change, accelerated sea level rise and a reduced Sierra snowpack are the most certain. Both will pose significant challenges for water supply and flood management. Water utilities have already begun to plan for these changes, but flood control agencies are lagging behind and face greater regulatory constraints. State leadership is needed to resolve some threats, including the risk of catastrophic failure in the Sacramento-San Joaquin Delta. This report was prepared as part of the Preparing California for a Changing Climate project.

Adapting Restoration for a Changing Climate Symposium

Delta Stewardship Council (Delta Council) | November 5th, 2021

Adapting to Change: Utility Systems and Declining Flows

California Urban Water Agencies (CUWA) | November 1st, 2017

During the recent historic drought, Californians responded to the call for emergency statewide water use reductions, which the state has recognized as a highly su

During the recent historic drought, Californians responded to the call for emergency statewide water use reductions, which the state has recognized as a highly successful outcome. However, this significant reduction in water demands has brought to light some unintended consequences of declining flows that ripple throughout the interconnected urban water cycle. These observations offer a preview into the potential impact of establishing permanent indoor water use targets at or below the thresholds achieved as a result of the governor’s emergency conservation mandate. California’s water industry leaders, including regulators and purveyors, are working to understand the system-wide impacts of increased conservation so that decision makers are better informed as they address California’s current and future water challenges. Through a partnership with California Association of Sanitation Agencies (CASA), Water Research Foundation(WRF), WateReuse California, and California Water Environment Association(CWEA), California WaterUrban Agencies(CUWA) has developed this white paper to provide decisionmakers, water/wastewater system managers, and other stakeholders an understanding of the impacts of declining flows resulting from substantial reductions in indoor water use and how utilities are adapting to these circumstances.

Adapting to Climate Change and Drought in Selected California Groundwater Basins: Local Achievements and Challenges

California Natural Resources Agency (CNRA) | August 27th, 2018

Climate change projections are for higher temperatures and extreme droughts by the end of the 21st century. This will alter the natural recharge of groundwater, including

Climate change projections are for higher temperatures and extreme droughts by the end of the 21st century. This will alter the natural recharge of groundwater, including decreased inflow from runoff, increased evaporative losses, and warmer and shorter winter seasons, impacts that are likely to exacerbate already existing groundwater overdraft in many basins. Additionally, the imported surface water that can be delivered from the Central Valley Project (CVP) and State Water Project (SWP) to areas reliant on this water for groundwater recharge and consumptive use is projected to be less reliable and more expensive. Yet groundwater is a critical water supply source during drought when it compensates for reduced surface water supplies. The need for proactive adaptation strategies to address the extreme droughts projected under climate change are frequently discussed, yet there are limited examples of such groundwater management strategies. This paper therefore explores:  1) How groundwater management agencies are planning for drought  2) What new approaches are currently being used that show promise for addressing the more extreme droughts projected under climate change? 

Adapting to Climate Change: Catching and Moving Water from Big Storms

California Department of Water Resources (DWR) | February 15th, 2024

Adapting wastewater management systems in California for water conservation and climate change

Sustainable and Resilient Infrastructure (Taylor & Francis) | February 27th, 2023