This report is one of three technical reports of Tracking California's Trash – a Proposition 84 Storm Water Grant Program project funded in large part by the State Water Board.  BASMAA and its project partners – 5 Gyres, City of Fremont, City of Oakland, City of San Jose, San Mateo Countywide Water Pollution Prevention Program, and Santa Clara Valley Urban Runoff Pollution Prevention Program provided the match funds.

The primary objectives of the project were to:

1. Develop and test scientifically sound and cost-effective stormwater and receiving water trash monitoring methods that allow agencies to measure sustained, long-term water quality improvements over time.
2. Fill critical information gaps on the effectiveness and costs/benefits of implementing specific stormwater BMPs (e.g., street sweeping) that address trash.

This report presents an evaluation of effectiveness and cost of two best management practices for trash – street sweeping and curb inlet screens.  

• Street Sweeping – Scientists and engineers have conducted numerous studies designed to quantify the effectiveness of street sweeping at removing various pollutants over the last 30 years.  The vast majority of these studies have focused on evaluating the effectiveness of different types of street sweepers in removing sediments and pollutants associated with sediment, such as PCBs, metals (i.e., mercury, copper, lead, zinc, etc.), petroleum products, chlorinated and organophosphate pesticides, and polybrominated diphenyl ethers (PBDEs).  In contrast, few have focused on their effectiveness in removing trash from street surfaces.  Although lessons learned from studies focused on sediment and other pollutants may assist practitioners in evaluating the trash control benefits of street sweeping, there are considerable differences in densities and other characteristics of these substances.  

• Curb Inlet Screens – Partial-capture devices are treatment devices that have not been certified/approved as full capture systems, but have some level of trash reduction benefit.  Curb inlet screens are one type of partial capture device.  Curb inlet screens are perforated screens or evenly spaced bars that are designed to fit outside or immediately within the storm drain curb opening.  Inlet screens may be fixed or retractable.  Retractable screens open either manually or hydraulically when a storm flow/volume is detected.  Since curb inlet screens block trash and debris from entering the storm drain inlet or storm drain, trash remains in the street and is removed by regular street sweeping or other measures.  

Monitoring was conducted at seven study areas located in the cities of Fremont, Oakland, and San Jose, California.  Monitoring activities included the removal of trash from streets, sidewalks, and drain inlets in three of the seven study areas (i.e., quantitative study areas) immediately before and after street sweeping events.  The collected trash was quantitatively characterized in terms of weight, volume, and item counts.  Quantification events were supplemented with qualitative On-land Visual Trash Assessments (OVTAs), which were conducted at all seven sites before, after and between street sweeping and rainfall events.

This report is one of three technical reports of Tracking California's Trash – a Proposition 84 Storm Water Grant Program project funded in large part by the State Water Board.  BASMAA and its project partners – 5 Gyres, City of Fremont, City of Oakland, City of San Jose, San Mateo Countywide Water Pollution Prevention Program (SMCWPPP), and Santa Clara Valley Urban Runoff Pollution Prevention Program (SCVURPPP) provided the match funds.

The primary objectives of the project were to:

1. Develop and test scientifically sound and cost-effective stormwater and receiving water trash monitoring methods that allow agencies to measure sustained, long-term water quality improvements over time.
2. Fill critical information gaps on the effectiveness and costs/benefits of implementing specific stormwater BMPs (e.g., street sweeping) that address trash.

This report presents an evaluation of a monitoring protocol (on-land visual assessment (OVTA)) to assess the levels of trash on land (streets and sidewalks) that could reach storm drain inlets as a surrogate for trash discharged from stormwater conveyances.  Although several studies have predicted or quantified trash discharges from stormwater conveyance systems, none appear to have attempted to empirically measure reductions over time from this specific trash transport pathway.  In the Los Angeles region, trash reductions are currently based on the geographical extent of trash control measure implementation and predetermined trash reduction values for each type of control measure implemented.  In the San Francisco Bay Area, trash reductions in stormwater are calculated using three methods.  The first two are equivalent to the two methods used in the Los Angeles region (i.e., areas treated by full capture systems and the results of agreed upon control measure specific studies).  The third, on-land visual assessment, is currently Bay Area specific.  The OVTA is a qualitative protocol that results in observations of trash levels on streets and sidewalks in specific assessment areas.  The protocol assumes that the level of trash that is observed on streets and sidewalks is consistent with the level of trash discharged by stormwater conveyance systems.  Quantitative monitoring and OVTA assessments were conducted at seven study areas located in the cities of Fremont, Oakland, and San Jose, California.  Quantitative monitoring activities included the removal of trash from streets, sidewalks, and storm drain inlets.  The trash collected was characterized in terms of weight, volume, and item counts.  Quantification events were supplemented with qualitative OVTAs conducted before, after and between street sweeping, and before and after rainfall events.  In addition to OVTAs conducted as part of the project, the results of approximately 3,100 OVTAs conducted at roughly 1,200 assessment sites by SCVURPPP and SMCWPPP were utilized to address the project monitoring questions.

This report is one of three technical reports of Tracking California's Trash – a Proposition 84 Storm Water Grant Program project funded in large part by the State Water Board.  BASMAA and its project partners – 5 Gyres, City of Fremont, City of Oakland, City of San Jose, San Mateo Countywide Water Pollution Prevention Program, and Santa Clara Valley Urban Runoff Pollution Prevention Program provided the match funds.

The primary objectives of the project were to:

1. Develop and test scientifically sound and cost-effective stormwater and receiving water trash monitoring methods that allow agencies to measure sustained, long-term water quality improvements over time.
2. Fill critical information gaps on the effectiveness and costs/benefits of implementing specific stormwater BMPs (e.g., street sweeping) that address trash.

This report presents information on developing, testing, and evaluating monitoring methods designed to accurately calculate trash loading rates in stormwater conveyance systems and receiving waters that vary in type, size, flow, and location.  Standardized and reproducible monitoring methods to empirically measure trash loading (i.e., flux) in either stormwater discharges or receiving waters have not been available.  A literature review was carried out to analyze existing methods and projects that monitored trash within water bodies.  The review found that few municipalities and entities in the U.S. have attempted to evaluate concentrations and loads of trash discharged in receiving waters.  The biggest source of references was from studies designed to monitor plastic pollution in marine environments, mostly at sea.  Methods used during the project were based primarily on NOAA’s Marine Debris Monitor and Assessment Document, Algalita’s River Los Angeles Study, and 5 Gyres’ global estimate that compiled data from multiple partners to determine a global estimate for plastic pollution.  These studies suggested that using multiple trawls to capture samples of plastic pollution floating on the surface of a water body, with some focus on what is in the water column, would be the most successful approach.  Therefore, methods described in these studies were modified to capture trash samples in receiving waters to accommodate the higher flows observed in rivers, creeks, and channels during wet weather events.  Monitoring methods were evaluated in four creeks (three in the Bay Area: Colma Creek, Coyote Creek, and San Mateo Creek and one in Los Angeles: Arroyo Seco, a channelized river in Pasadena).  

On June 30, BASMAA convened over 40 experts at a biotreatment soil and tree round table to review the current soil specifications to determine if improvements to the specification can be made to positively impact the health of trees planted in bioretention areas.