PARENT SESSION
PM18 - TMDLs
Monday, 18 November 2002
8:00 AM to 6:30 PM
Exhibit Hall
(P390) A new 303(d) listing and TMDL requirement based on citizen monitoring in a southern California watershed.
Luce, Shelley*,1,2, Abramson, Mark1, 1 Heal the Bay, Santa Monica, CA, USA2 University of California, Los Angeles, Los Angeles, CA, USA
ABSTRACT- Heal the Bay's Stream Team is a citizen monitoring program designed to assess the ecological health of streams and riparian habitat in the Santa Monica Mountain region of southern California. Data from the Stream Team program were the basis of a new listing for sediment impairment in Malibu Creek on California's most recent 303(d) list. This is the first listing for sediment in the Los Angeles-Ventura region, and may be the state's first 303(d) listing based entirely on citizen-collected monitoring data. We present the program's three-pronged approach to monitoring (water chemistry monitoring, identification and mapping of in-stream and riparian habitats, and benthic macroinvertebrate sampling) and how it provides useful data for regulation and decision-making, and specifically for determining impairments and restoration needs. Stream Team assessed Malibu Creek's benthic macroinvertebrate community and physical habitat structure using the California Department of Fish and Game's California Stream Bioassessment Procedure. The watershed showed signs of ecological impairment due to sediment. Low physical habitat scores and in-stream mapping data reflected the influence of heavy sediments in causing reduced macroinvertebrate habitat quality and availability. The dominant taxa in the watershed were sediment-tolerant, rapid colonizers adapted to collecting organic matter as a food source. The low diversity of substrates and simplicity of the physical environment are primarily responsible for the overall low bioassessment scores in this watershed. The new 303d listing will result in stricter controls on sediment discharges to the creek, and development of a Total Maximum Daily Load regulation for sediment in the watershed.
Key words: TMDL, monitoring, sediment