Microplastic pollution is widely detected in US municipal wastewater treatment plant effluent

Environmental Pollution (Elsevier) | August 27th, 2016

Municipal wastewater effluent has been proposed as one pathway for microplastics to enter the aquatic environment. Here we present a broad study of municipal wastewater t

Municipal wastewater effluent has been proposed as one pathway for microplastics to enter the aquatic environment. Here we present a broad study of municipal wastewater treatment plant effluent as a pathway for microplastic pollution to enter receiving waters. A total of 90 samples were analyzed from 17 different facilities across the United States. Averaging all facilities and sampling dates, 0.05 ± 0.024 microparticles were found per liter of effluent. Though a small value on a per liter basis, even minor municipal wastewater treatment facilities process millions of liters of wastewater each day, yielding daily discharges that ranged from ∼50,000 up to nearly 15 million particles. Averaging across the 17 facilities tested, our results indicate that wastewater treatment facilities are releasing over 4 million microparticles per facility per day. Fibers and fragments were found to be the most common type of particle within the effluent; however, some fibers may be derived from non-plastic sources. Considerable inter- and intra-facility variation in discharge concentrations, as well as the relative proportions of particle types, was observed. Statistical analysis suggested facilities serving larger populations discharged more particles. Results did not suggest tertiary filtration treatments were an effective means of reducing discharge. Assuming that fragments and pellets found in the effluent arise from the ‘microbeads’ found in many cosmetics and personal care products, it is estimated that between 3 and 23 billion (with an average of 13 billion) of these microplastic particles are being released into US waterways every day via municipal wastewater. This estimate can be used to evaluate the contribution of microbeads to microplastic pollution relative to other sources (e.g., plastic litter and debris) and pathways (e.g., stormwater) of discharge.

Microplastic Strategy Update on behalf of the Regional Monitoring Program (RMP) for Water Quality in San Francisco Bay

San Francisco Estuary Institute (SFEI) | December 2nd, 2019

Based on the detection of microplastics in San Francisco Bay surface water and Bay Area wastewater effluent in 2015, the Regional Monitoring Program for Water Quality in

Based on the detection of microplastics in San Francisco Bay surface water and Bay Area wastewater effluent in 2015, the Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) convened a Microplastic Workgroup (MPWG) in 2016 to discuss the issue, identify management information needs and management questions (MQs), and prioritize studies to provide information to answer these management questions. The MPWG meets annually to review on-going microplastic projects and to conduct strategic long-term planning in response to new information in this rapidly evolving field.

Missing the Boat on Freshwater Fish Conservation in California

Conservation Letters (Society for Conservation Biology) | March 30th, 2016

Population growth and increasing water‐use pressures threaten California's freshwater ecosystems and have led many native fishes to the brink of extinction. To guide fi

Population growth and increasing water‐use pressures threaten California's freshwater ecosystems and have led many native fishes to the brink of extinction. To guide fish conservation efforts, we provide the first systematic prioritization of river catchments and identify those that disproportionately contribute to fish taxonomic diversity. Using high‐resolution range maps of exceptional quality, we also assess the representation of fish taxa within the state's protected areas and examine the concordance of high‐priority catchments with existing reserves and among distinct taxonomic groups. Although most of the state's native fishes are found within protected areas, only a small proportion of their ranges are represented. Few high‐priority catchments occur within protected areas, suggesting that fish conservation will require active management and targeted river restoration outside of reserves. These results provide the foundation for systematic freshwater conservation planning in California and for prioritizing where limited resources are allocated for fish recovery and protection.

Mission Bay Historical Ecology Reconnaissance Study: Data Collection Summary (Technical Report)

San Francisco Estuary Institute (SFEI) | February 1st, 2016

The goals of the Mission Bay Historical Ecology Reconnaissance Study were to collect and compile high-priority historical data about the Mission Bay landscape, identify

The goals of the Mission Bay Historical Ecology Reconnaissance Study were to collect and compile high-priority historical data about the Mission Bay landscape, identify sources that could help to develop a deeper understanding of early ecological conditions, and to identify future possible research directions based on the available data. This technical memorandum is intended to document the archives consulted during the reconnaissance study, summarize the collected and compiled data, and to identify potential next steps. A separate technical presentation to project staff and advisors will summarize the preliminary findings and questions generated from a review of the historical dataset. Ultimately, this research is intended to support the San Diego Audubon Society’s Mission Bay Wetlands Conceptual Restoration Plan (CRP) and the ReWild Mission Bay project. Also on this topic: Mission Bay Historical Ecology Reconnaissance Study: Data CollectionSummary and Initial Findings (Presentation)

Modeling Functional Flows in California’s Rivers

Frontiers in Environmental Science (Frontiers) | March 11th, 2022

Modeling guides groundwater management in a basin with river–aquifer interactions

California Agriculture (UCANR) | March 13th, 2018

The Sustainable Groundwater Management Act (SGMA) of 2014 seeks to maintain groundwater discharge to streams to support environmental goals. In Scott Valley, in Siskiyou

The Sustainable Groundwater Management Act (SGMA) of 2014 seeks to maintain groundwater discharge to streams to support environmental goals. In Scott Valley, in Siskiyou County, the Scott River and its tributaries are an important salmonid spawning habitat, and about 10% of average annual Scott River stream flow comes from groundwater. The local groundwater advisory committee is developing groundwater management alternatives that would increase summer and early fall stream flows. We developed a model to provide a framework to evaluate those alternatives. We first created a water budget for the Scott Valley groundwater basin and integrated the detailed, spatiotemporally distributed water budget results into a computer model of the basin that simultaneously accounted for groundwater flow, stream flow and landscape water fluxes. Different conceptual representations (using the MODFLOW RIV package and MODFLOW SFR package) of the stream–aquifer boundary provided significantly different results in the seasonal dynamics of groundwater–surface water fluxes. As groundwater sustainability agencies draw up plans to meet SGMA requirements, they must choose and test simulation tools carefully.

Modeling residential development in California from 2000 to 2050: Integrating wildfire risk, wildland and agricultural encroachment

Land Use Policy (Elsevier) | November 1st, 2014

Between 1940 and 2000, nearly 10 million housing units were constructed throughout California. This increased interaction between human and natural communities creates a

Between 1940 and 2000, nearly 10 million housing units were constructed throughout California. This increased interaction between human and natural communities creates a number of significant socio-ecological challenges. Here we present a novel spatially explicit model that allows better characterization of the extent and intensity of future housing settlements using three development scenarios between 2000 and 2050. We estimate that California’s exurban land classes will replace nearly 12 million acres of wild and agricultural lands. This will increase threats to ecosystems and those presented by wild fire, as the number of houses in ‘very high’ wildfire severity zones increases by nearly 1 million.

Modeling the effect of habitat availability and quality on endangered winter-run Chinook salmon (Oncorhynchus tshawytscha) production in the Sacramento Valley

Ecological Modelling (Elsevier) | March 13th, 2021

Reconciliation between water uses and sustaining aquatic species populations requires an effort to identify and quantify essential habitat characteristics for ecosystem h

Reconciliation between water uses and sustaining aquatic species populations requires an effort to identify and quantify essential habitat characteristics for ecosystem health and valuation methods to predict ecosystem response to restoration actions. This process is particularly challenging for anadromous fish species such as California's Sacramento River winter-run Chinook salmon, due to their limited geographic range and diverse life history habitat requirements. Tools, such as life-cycle models, are needed to manage population dynamics and quantify the composite effects of processes across space and time. Nevertheless, complex institutions can hinder result interpretation and communication, and limit model use in decision-making. This paper focuses on the federally endangered and endemic Sacramento River winter-run Chinook (Oncorhynchus tshawytscha) by developing a Winter-Run Habitat-based Population Model (WRHAP). WRHAP is a conceptual, freshwater rearing stage model that includes alternative rearing habitats reported in the literature (e.g., floodplains, off-channel and tributaries), defines rules of habitat use based on instream conditions, and incorporates a juvenile growth module that combines bioenergetics modeling with empirical growth rates. Model outputs reasonably follow observed out-migration patterns and provide a realistic smolt size distribution arriving at the San Francisco Bay. This effort demonstrates the importance of currently “non-critical” habitats (as defined by the Endangered Species Act) for juvenile development, with floodplain habitat contributing to a quarter of out-migrating biomass (despite < 18% availability and <10% of total rearing days), and off-channel growth being one of the most sensitive parameters (explaining ~13% of average juvenile weight variance). The model shows the utility of a simple population model to explore relationships between habitat quality/quantity and juvenile development, and to assist water/environmental management and decision-making processes focused on species recovery.

Mokelumne watershed avoided cost analysis: Why Sierra fuel treatments make economic sense

Sierra Nevada Conservancy | April 10th, 2014

High-severity wildfires in forests of California’s Sierra Nevada pose a serious threat to people and nature. Although proactive forest management can reduce the risk of

High-severity wildfires in forests of California’s Sierra Nevada pose a serious threat to people and nature. Although proactive forest management can reduce the risk of high-severity wildfire, the pace and scale of fuel treatments is insufficient, given the growing scope of the problem. Using the upper Mokelumne River watershed as a representative case, we sought to answer the following question: Does it make economic sense to increase investment in fuel treatments to reduce the risk of large, damaging wildfires? Our analysis suggests that the economic benefits of landscape- scale fuel-reduction treatments far outweigh the costs of wildfire. 

Mono Lake Committee request for an emergency action to protect Mono Lake and its public trust resources

California State Water Resources Control Board (SWRCB) | December 16th, 2022