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DECISION ID |
16622 |
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| Pollutant: |
Invasive Species |
| Final Listing Decision: |
List on 303(d) list (TMDL required list) |
| Last Listing Cycle's Final Listing Decision: |
New Decision |
| Revision Status |
Revised |
| Sources: |
Nonpoint Source | Point Source |
| Expected TMDL Completion Date: |
2021 |
| Impairment from Pollutant or Pollution: |
Pollutant |
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| Weight of Evidence: |
This pollutant is being considered for placement on the section 303(d) list under section 3.10 of the Listing Policy. Under section 3.10, waters are listed when a declining trend in water quality is substantiated.
Two lines of evidence are available in the administrative record to assess this pollutant. One of 1 site showed an increase in density of mud snails over the three years of sampling (2006, 2007, 2008) and 1 out of 3 sites sampled showed medium or high densities of mud snail in 2008. (One site also exhibited a low density of mudsnails in 2008.)
At high numbers, mud snails can completely cover a stream bed and damage local stream ecosystems. The colonies outcompete native aquatic invertebrates that the watersheds fish and amphibians rely on for food, disrupting the entire food web.
Benthic macroinvertebrates as measured by Southern California IBI (index of biological integrity) in Solstice Creek were good in 2005 indicating no impairment of the benthic community structure.
Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.
This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Data was collected over a three years time frame and a baseline condition of zero abundance of the invasive species was used.
3. One of one sites showed an increase in density of mud snails over a three years of sampling and one of three sites sampled showed medium or high densities of mud snail in 2008.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are met. |
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| RWQCB Board Decision / Staff Recommendation: |
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| SWRCB Board Decision / Staff Recommendation: |
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| USEPA Decision: |
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| LOE ID: |
28704 |
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| Pollutant: |
Invasive Species |
| LOE Subgroup: |
Population/Community Degradation |
| Matrix: |
Water |
| Fraction: |
None |
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| Beneficial Use: |
Warm Freshwater Habitat |
| Aquatic Life Use: |
Fish Migration | Fish Spawning | Wildlife Habitat |
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| Number of Samples: |
1 |
| Number of Exceedances: |
1 |
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| Data and Information Type: |
Benthic macroinvertebrate surveys |
| Data Used to Assess Water Quality: |
One of one sites showed an increase in density of mud snails over the three years of sampling (2006, 2007, 2008) and one of three sites sampled showed medium or high densities of mud snail in 2008. |
| Data Reference: |
New Zealand Mudsnail Surveys July 2006, July 2007 and October 2008 Santa Monica Mountains. Santa Monica Bay Restoration Commission / Santa Monica Baykeeper.
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| Water Quality Objective/Criterion: |
The Basin Plan states that: "All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant or animal, or aquatic life. Compliance with this objective will be determined by use of indicator organisms, analysis of species diversity, population density, growth anomalies, bioassays of appropriate duration or other appropriate methods as specified by the State or Regional Board. |
| Objective/Criterion Reference: |
Water Quality Control Plan Los Angeles Region R4 Basin Plan |
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Basin Plan Amendments to the Water Quality Control Plan Los Angeles Region R4 Basin Plan as of 02/02/2009 |
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| Evaluation Guideline: |
Presence of high densities and increasing densities. While quantitative and predictive research continues, due to its ability to attain extremely high densities, the impacts of the mudsnails on aquatic ecosystems where it occurs in the western U.S. are large and include: decreased densities of native macroinvertebrates and reduced food resources; decreased whole-stream algal production; poor food source in that mudsnails are much more difficult to digest, with their hard shells and operculum than are the thin-shelled, native pulmonate snails that do not have opercula or than soft-bodied, aquatic insect larvae. |
| Guideline Reference: |
The New Zealand Mudsnail Invades the Western United States. Aquatic Nuisance Species Digest Volume 4 No. 4. |
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| Spatial Representation: |
Three sites were sampled in the following locations in Solstice Canyon Creek: NPS U.S. wood bridge; U.S. 2nd bridge; and1st bridge-PCH culvert. |
| Temporal Representation: |
The 1st bridge-PCH culvert site was sampled in in July of 2006, July of 2007 and October of 2008. The other two sites were sampled July of 2007 and October of 2008. |
| Environmental Conditions: |
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| QAPP Information: |
Data was collected as detailed in the Santa Monica Bay Restoration Commission and Santa Monica Baykeeper New Zealand Mudsnail Surveys. |
| QAPP Information Reference(s): |
New Zealand Mudsnail Surveys July 2006, July 2007 and October 2008 Santa Monica Mountains. Santa Monica Bay Restoration Commission / Santa Monica Baykeeper.
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| LOE ID: |
30182 |
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| Pollutant: |
Invasive Species |
| LOE Subgroup: |
Population/Community Degradation |
| Matrix: |
Water |
| Fraction: |
None |
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| Beneficial Use: |
Warm Freshwater Habitat |
| Aquatic Life Use: |
Fish Migration | Fish Spawning | Wildlife Habitat |
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| Number of Samples: |
0 |
| Number of Exceedances: |
0 |
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| Data and Information Type: |
Benthic macroinvertebrate surveys |
| Data Used to Assess Water Quality: |
One sampled in 2005 - IBI scores was calculated at 63 category good |
| Data Reference: |
Malibu Bioassessment Winter 2005 |
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| Water Quality Objective/Criterion: |
The Basin Plan states that: "All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant or animal, or aquatic life. Compliance with this objective will be determined by use of indicator organisms, analysis of species diversity, population density, growth anomalies, bioassays of appropriate duration or other appropriate methods as specified by the State or Regional Board. |
| Objective/Criterion Reference: |
Water Quality Control Plan Los Angeles Region R4 Basin Plan |
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Basin Plan Amendments to the Water Quality Control Plan Los Angeles Region R4 Basin Plan as of 02/02/2009 |
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| Evaluation Guideline: |
The IBI is a multi-metric assessment that employs biological metrics that respond to a habitat or water quality impairment. Each of the biological metrics measured at a site are converted to an IBI score then summed. These cumulative scores are then ranked as very good (80-100), good (60-79), fair (40-49), poor (20-39) and very poor (0-19) habitat conditions. Sites with scores below 39 are considered to have impaired conditions. |
| Guideline Reference: |
A Quantitative Tool for Assessing the Integrity of Southern Coastal California Streams. Environmental Management Vol. 35, No. 4, pp. 493-504. |
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| Spatial Representation: |
One site in Solstice Creek was sampled, SC14 |
| Temporal Representation: |
Sites were sampled in winter of 2005. |
| Environmental Conditions: |
Benthic macroinvertebrate populations and IBI scores may also be affected by a wide range of anthropogenic stressors. |
| QAPP Information: |
Data was collected in compliance with California Stream Bioassessment Procedure. Collection procedures were audited by California Department of Fish and Game in 2006. |
| QAPP Information Reference(s): |
California Stream Bioassessment Procedure (Protocol Brief for Biological and Physical/Habitat Assessment in Wadeable Streams) California Department of Fish and Game Water Pollution Control Laboratory Aquatic Bioassessment Laboratory Revision Date - December, 2003 |
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California Stream Bioassessment Procedure Biological and Physical Habitat Field Audit |