| Water Body Name: | Grayson Creek |
| Water Body ID: | CAR2073301020080624163514 |
| Water Body Type: | River & Stream |
Lines of Evidence (LOEs) for Decision ID 7643 |
| LOE ID: | 5409 |
| Pollutant: | Trash |
| LOE Subgroup: | Pollutant-Nuisance |
| Matrix: | Not Specified |
| Fraction: | None |
| Beneficial Use: | Wildlife Habitat |
| Number of Samples: | 5 |
| Number of Exceedances: | 2 |
| Data and Information Type: | Occurrence of conditions judged to cause impairment |
| Data Used to Assess Water Quality: | Data available consist of photographic evidence of trash and interpretation of these photos by an experienced trash assessment specialist. Each photograph was analyzed to establish the RTA score for the level of trash and threat to aquatic life parameters, which relate to impairment of REC2 and WILD, respectively. Only those photos clear enough to establish these RTA scores were relied on for the listing determination. This waterbody had threat to aquatic life parameter scores in the poor category (indicating threat to Wildlife Habitat beneficial uses) at two different locations on two different dates. |
| Data Reference: | Archive of Trash Photos for Old Alameda Creek submitted for 2008 303(d) list consideration |
| Assessment by Matt Cover of Trash Photos (submitted to Region 2 in response to 2008 Data Solicitation) | |
| Archive of Trash Photos for Grayson Creek submitted for 2008 303(d) list consideration | |
| Water Quality Objective/Criterion: | The Basin Plan prohibits discharge of Rubbish, refuse, bark, sawdust, or other solid wastes into surface waters or at any place where they would contact or where they would be eventually transported to surface waters, including flood plain areas.
The Basin Plan has a narrative objective for floating material, Waters shall not contain floating material, including solids, liquids, foams, and scum, in concentrations that cause nuisance or adversely affect beneficial uses. The Basin Plan has a narrative objective for settleable material, Waters shall not contain substances in concentrations that result in the deposition of material that cause nuisance or adversely affect beneficial uses. |
| Objective/Criterion Reference: | San Francisco Bay Basin (Region 2) Water Quality Control Plan (Basin Plan) |
| Evaluation Guideline: | If the Rapid Trash Assessment (RTA) Parameter 1 (Level of Trash) is in the poor condition category (scores 0-5), REC2 is not supported. This level of trash distracts the eye on first glance, making the site unsuitable for recreation. The RTA defines poor condition for this parameter as follows, trash distracts the eye on first glance. Stream, bank surfaces, and immediate riparian zone contain substantial levels of litter and debris (>100 pieces). Evidence of site being used frequently by people: many cans, bottles, and food wrappers, blankets, clothing. Regional Water Board staff trained in the RTA inspected the available photographic evidence and applied the assessment method to determine the Level of Trash score.
If the RTA Parameter 3 (Threat to Aquatic Life) is in the poor condition category (scores 0-5), then WILD is not supported. This level of trash is a large amount (>50 pieces) of transportable, persistent, buoyant litter that is detrimental to aquatic life. The RTA defines poor condition for this parameter as follows, large amount (>50 pieces) of transportable, persistent, buoyant litter such as: hard or soft plastics, balloons, Styrofoam, cigarette butts; toxic items such as batteries, lighters, or spray cans; large clumps of yard waste or dumped leaf litter; or large amount (>50 pieces) of settleable glass or metal. Regional Water Board staff trained in the RTA inspected the available photographic evidence and applied the assessment method to determine the Threat to Aquatic Life score. |
| Guideline Reference: | A Rapid Trash Assessment Method Applied to Waters of the San Francisco Bay Region:Trash Measurement in Streams |
| Spatial Representation: | Photographic evidence was analyzed using the RTA methodology for this waterbody for five different locations spanning dates from 2006 through 2007. The assessments were conducted at the following locations: Elinora Drive Bridge, trail between Center Ave. and 2nd Ave., Center Ave. Bridge, Pacheco Blvd., and Imhoff Drive Bridge. |
| Temporal Representation: | Photographic evidence was collected for this waterbody on four separate dates from 2006 and 2007 including:
Elinora Drive Bridge on 4/3/2006, 1/4/2007, 2/13/2007 Trail between Center Ave. and 2nd Ave. on 4/3/2006, 12/8/2006, 2/13/2007 Center Ave. Bridge on 2/13/2007 Pacheco Blvd. on 1/4/2007 Imhoff Drive Bridge on 4/3/2006 |
| Environmental Conditions: | |
| QAPP Information: | Assessments of the photographic evidence using the RTA were performed by Regional Water Board staff person who was a co-author of the Rapid Trash Assessment methodology.
Assessments based on photographic evidence were only conducted when sufficient reach-scale and close-up photos were available for a site on a specific date. Photos used for the evaluation needed to be numerous enough and clear enough to document the level of trash at the site in a similar way as the assessor would experience during an actual site visit in the field. For example, at a minimum, one reach-scale photograph (showing at least a 100 linear foot section of the waterbody) and two close-up photographs (of representative trash deposits) were required. |
| QAPP Information Reference(s): | |