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Problem Regional ConditionsLongitudinal Trends Case Study: San Mateo Creek Watershed Trash adversely affects numerous beneficial uses of waters, particularly.

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Presentation on theme: "Problem Regional ConditionsLongitudinal Trends Case Study: San Mateo Creek Watershed Trash adversely affects numerous beneficial uses of waters, particularly."— Presentation transcript:

1 Problem Regional ConditionsLongitudinal Trends Case Study: San Mateo Creek Watershed Trash adversely affects numerous beneficial uses of waters, particularly aesthetics, recreation and aquatic habitats Urban runoff is the primary source of trash in the ocean, which can harm aquatic life through entanglement or ingestion Certain trash items, such as discarded medical waste, human or pet waste, and broken glass can threaten human health Household and industrial wastes may contain toxic substances of concern to humans, wildlife, and aquatic life A rapid trash assessment method applied to waters of the San Francisco Bay Region: trash measurement in streams Steven M. Moore Matthew R. Cover, and Anne Senter Surface Water Ambient Monitoring Program, San Francisco Bay Regional Water Quality Control Board, Oakland, CA Methods Conclusions We developed a Rapid Trash Assessment (RTA) protocol that generates assessment scores, provides quantitative measurements of trash levels, and documents rates of return of trash, based on a quantitative tally of trash pieces picked up in a 100 foot, landmarked reach of stream Six scoring condition categories, scored between Level of Trash: a qualitative first impression 2. Actual Number of Trash Items Found: greater than 100 pieces per reach receives a poor score of 5 or less 3. Threat to Aquatic Life: persistent, buoyant, ingestible, and toxic trash items 4. Threat to Human Health: medical waste, syringes, diapers, condoms and human or pet waste that may contain dangerous bacteria or viruses 5. Illegal Dumping and Littering: direct placement of trash items from adjacent land use practices or site accessibility 6. Accumulation of Trash: accumulation from upstream locations via downstream transport 26 sites in six urbanized watersheds; 85 total site visits Comparison between watersheds: bottom of the watershed (BOTW) sites (near tidal influence) Comparison within watersheds: tributaries and/or public-access sites along a longitudinal gradient Each site visited 3 to 4 times to estimate trash deposition in dry and wet seasons Picked up trash during each visit Determine regional conditions, longitudinal patterns, and deposition rates Results confirm remarkably high levels of trash in all urban streams surveyed On average, 293 pieces of trash were collected per 100 foot reach of stream, or about 3 pieces per linear foot of stream Plastic, most of it disposable packaging, made up over 50% of this total, or 1.51 pieces per linear foot of stream. Glass (21%) and biodegradable items including paper (10%) were also commonly found. 72% of items found below the high-water mark Study Design Case Study: Baxter Creek at Booker T. Anderson Park Average Condition Category Scores by Season and Site Type (BOTW = Bottom of the Watershed) Bottom of the watershed site Highest recorded number of pieces of trash: 1133 / 100 ft. Highest recorded trash deposition rate: 7.47 pieces / reach-day Triple whammy of trash sources: dumping, littering, and downstream transport (accumulation) The ubiquitous, unacceptably high levels of trash in waters of the San Francisco Bay Region warrant a comprehensive and progressive program of education, warning, enforcement and consideration of structural controls and treatment. The preponderance of trash accumulation from upstream sources suggests that the public-at-large do not grasp the risks associated with littering on streets that drain to waters, let alone in parks that have running streams. Plastic is the dominant source of trash found at lower watershed sites where trash accumulates, suggesting that urban runoff is a major source of floatable plastic found in the Bay and ocean and on beaches as marine debris. Trash source hotspots near creek channels, e.g. parks, schools, arterial roadways, or poorly kept commercial facilities, appear to contribute a significant portion of the trash deposition at lower watershed sites. Dry season deposition of trash, associated with wind and dry season runoff, contributes measurable levels of trash to downstream locations. Parks that have more evident management of trash by City staff and local volunteers, including the placement of trash receptacles and cleanup near/within the creek channel, have measurably less trash pieces and higher RTA scores. The Rapid Trash Assessment (RTA) can distinguish clean and dirty sites, engage citizens, inform the development of site- specific remedies, and evaluate the success of future management actions. Bottom of the watershed (BOTW) sites received the lowest scores for qualitative and quantitative trash levels, aquatic habitat, and accumulation, as a result of higher levels of plastic Accumulation from upstream sources was significant even during the dry season at BOTW sites Littering and dumping scores were similar between seasons and site types. Gateway Park, like other publicly accessible bottom of the watershed (BOTW) sites, had high deposition rates associated with littering in the dry season and accumulation from upstream sources in the wet season. The middle mainstem site, Arroyo Court Park, exhibited similar but less marked patterns as the BOTW Gateway Park site. Scores improved at the upper watershed, residential Polhemus Creek site following trash pickup, but wet weather brought a significant return of trash, resulting in a lower score. The upper San Mateo Creek site, which is upstream of the urban boundary but affected by historic roadside littering, exhibited a more desirable pattern in trash deposition. The site improved dramatically following pickup of trash (i.e. a management action), and saw less return of trash with wet weather. Photo by Friends of Coyote Creek, January 27, 2004, Julian Street Bridge, downtown San Jose *Miscellaneous includes cigarette butts, golf and tennis balls, balloons, foam rubber, ceramic pots/shards, and hose pieces *


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