Monitoring Plan for the Santa Margarita River

Purpose of the Monitoring Program

May 2002

The purpose of the Santa Margarita River monitoring program is to (1) provide a quantitative assessment of the key ecological processes and ecological integrity of the Santa Margarita river system below the Temecula-Murrieta Creek confluence, (2) determine the potential effects of stressors on the system, and (3) evaluate the success of stressor abatement strategies and allow adaptive management to modify and refine strategies. The development of the monitoring program was initiated in response to the upcoming discharges of water to the river as part of the water rights settlement between USMC Base Camp Pendleton and the Rancho California Water District. The Nature Conservancy, which has an interest in maintaining and enhancing the resource values of the Santa Margarita River system, participated in development of a settlement agreement that provided for the maintenance of base flows in the river. Maintaining base flows and other physical, hydrological, and biological processes and conditions is critical to maintaining the high resource values of the system. The monitoring program is designed to measure a number of metrics relating to these processes and conditions so that resource values can be assessed and managed at the watershed scale to ensure their long-term conservation. Decision-makers within the watershed can use the results of the monitoring program to determine the current status of resources, measure changes over time, and assess the potential effects of proposed activities, such as development and water supply management, on the critical processes and conditions of the river system.

This monitoring plan summarizes the conservation targets and associated key ecological factors identified for the Santa Margarita River system (Section 2.0), discusses stresses and sources of these stresses and their potential effects (Section 3.0), and describes physical, hydrological, and biological elements for monitoring potential changes in the system associated with the array of stressors (Section 4.0) and the rationale for their inclusion. The monitoring plan also recommends a sampling design for the field monitoring program, suggested field monitoring methods, and a monitoring schedule.

Program Objectives

The ecological integrity or condition of the river is a function of an array of interrelated physical, hydrological, and biological factors. In many instances, our understanding of these interrelationships in the Santa Margarita River system is poor. In addition, a number of these factors may be influenced by stresses present in the Santa Margarita watershed, the prescribed settlement flows, or other strategies to abate threats to the Santa Margarita River system and, therefore, are subject to change even as we attempt to monitor their baseline patterns. The monitoring program has been developed to address the following general objectives:

1. Identify and monitor key ecological factors of the Santa Margarita River system to gain a better understanding of the baseline patterns of key riverine processes operating in the watershed, their range of variation, and their interrelationships.

2. Assess ecological integrity of the Santa Margarita River system, evaluate effects of stressors, and monitor future changes from stressor abatement strategies.

3. Document changes in the quality of habitats for target species to inform management decisions and evaluate management actions.

4. Communicate information on the condition of the Santa Margarita River system to the general public, resource users, resource managers, regulators, and researchers.

For more information, contact Jerre Stallcup (email: jastallcup@consbio.org) or Mike White (email: mdwhite@consbio.org) in the CBI San Diego office (phone: 760-634-1590).