The Santa Clara River, its tributaries and the associated riparian or streamside habitats comprise the largest natural river systems remaining in Southern California. In 1991 it became apparent to agencies regulating the Santa Clara River and the various organizations with interests along the river that a consensus plan was needed to manage the river and its many
resources. As a result, all involved parties agreed to work together and formed the Project Steering Committee (PSC) to oversee the planning process. Among the issues of concern identified by the PSC was the need for development of a management plan focused on addressing water quality and quantity in the Santa Clara River. In November 2003, AMEC
Earth and Environmental, Inc. (AMEC) was retained by the Ventura County Watershed Protection District (VCWPD), under the direction of the State Water Resources Control Board (SWRCB), to compile and review existing water quality data, determine data gaps, and develop a Comprehensive Monitoring Plan (CMP) for the Santa Clara River. The goals of this plan are to: 1) develop baseline conditions for the watershed; 2) have a mechanism to measure improvements or degradations in the water quality; and 3) provide sufficient information to assist the PSC in making important management decisions regarding the watershed. To develop the CMP, AMEC gathered existing monitoring data for the Santa Clara River, assembled a comprehensive water quality and flow database, identified data gaps, evaluated the constituents monitored and made recommendations regarding modifications to existing monitoring protocol and procedures necessary to ensure development of a comprehensive water quality monitoring program.

In general, the results of the Data Gap Analysis revealed clear data gaps for fecal coliform, total suspended solids (TSS), total dissolved solids (TDS), flow, all metals, nitrite, phosphorus, phosphate, chemical constituents such as polychlorinated biphenyls (PCBs), and toxicity testing. Further, sampling appeared to be the most prevalent in the Upper Santa Clara River
watershed compared to all other subwatersheds. Based on these results and the identified need to develop a monitoring program that would establish baseline conditions in the watershed, AMEC has recommended a slightly modified systematic sampling program and selected monitoring locations at regular intervals along the Santa Clara River. The recommended frequency of sampling at all stations is monthly for most chemical and physical parameters and for total and fecal coliform. Sediment sampling and bioassessment monitoring has been recommended on an annual basis at only specific sites on the watershed. Additional measurements can be added at any time to address local or regional environmental issues.
Flow, measured as discharge, is one key variable that needs greater attention because it is a keystone for any TMDL calculation. Therefore, monthly flow sampling has been recommended at all monitoring locations. Sites that are currently measuring physical conditions on a real-time, daily, or weekly basis shall remain in operation.

Data quality objectives (DQOs) are described for each type of testing. Methods will be chosen by stakeholders based on their intended use to fulfill monitoring data gaps, while maintaining consistency with past measurements, where appropriate. DQOs such as precision, accuracy, and sensitivity will be considered during method selection. Additionally, funding and
implementation for the recommended monitoring plan will be determined by the stakeholders prior to the initiation of any sampling program.