California Stream Condition Index Csci Score Analysis Of Streams Sampled From 1998 To 2017 In The San Francisco Bay Region

Human impacts to California's streams have altered the state's riparian and hydrological landscape. This is a critical issue with regard to natural resources, including ecosystem services such as water availability and water quality. Regulations have a limited amount of impact on the improvement of this landscape and can also become complicated by politics. Scientific advances have developed ways to quantify and describe the quality of streams, this includes the development of the California Stream Condition Index (CSCI) which is based on benthic macroinvertebrate (BMI) population numbers and functions. This index allows scientists to not only score the quality of a stream, but to analyze the details of the data that produce the CSCI scores. The CSCI scores also provide a means to spatially analyze large data sets of stream quality. This project evaluates the spatial distribution of CSCI scores for the San Francisco Bay region. Several streams within the San Francisco Bay region confirm that very urban and developed areas contain highly impacted streams, whereas areas that are less or not urban and developed (rural) have less impacted or higher quality streams. The variation in CSCI scores within a stream over time were analyzed for ten streams in the San Francisco Bay region. The data were limited, therefore spatial consideration of where samples were collected, was accounted for. Predictably, lower CSCI scores were indicative of urban and developed areas; and higher CSCI scores were indicative of less impacted areas. The CSCI quantitative scores were less indicative of possible temporal trends in stream quality, however the CSCI qualitative categories were more indicative of possible temporal trends in stream quality. More data analysis will be required to prove any definitive temporal trends in stream quality with regard to the CSCI number scores. These CSCI data will be more useful when compared with additional stream data such as physical habitat and water quality data.