San Diego Management & Monitoring Program

Threats and Stressors
Urban Aseasonal Flow Study

in progress

Project description

Non-native plants and animals with associated changes to ecological processes cause threats to native plants and animals. The San Diego Management and Monitoring Program’s Management Strategic Plan (MSP) identifies these threats and stressors, and presents goals and objectives to monitoring their affects. The MSP has prioritized the study of the impacts of urban aseasonal flow on local and regional stream systems. The issue of seasonal wetlands in urbanizing landscapes has received varying amount of attention. The runoff can create a range of results from increased soil moisture levels, to geomorphic changes in creeks and perennial flows in xeric landscapes. USGS is working with SDMMP and their partners in the Management Strategic Plan Area (MSPA) to determine what GIS covariates of land cover/land use might correlate with field measurements of the phenology of water presence in small watersheds. This will help to identify where urban runoff is providing habitat for aquatic nonnative problem species in areas inhabited by arroyo toads, western pond turtles and vernal pool areas. Study sites were selected using a spatial model including layers for watershed size, land use, and conserved lands. Site selection also considered surface water monitoring sites for arroyo toad monitoring (Brown et al. 2016) and surface flow monitoring stations used by the California Water Quality Control Board, San Diego Region (SDRWQCB unpub. data). The combination of the three studies provide a network of surface water availability and temperature data from coastal San Diego to the foothills of the Cuyamaca, Laguna, Palomar, and Santa Margarita mountain ranges. A total of 56 sites were selected, assessed, and Stream Temperature, Indeterminacy, and Conductivity (STIC) loggers were deployed. This adds to the existing 64 loggers that were deployed to measure Arroyo toad habitat. For 120 loggers, the following steps took place. 1. The logger was placed in the field and the location was recorded with a high resolution GPS. 2. Photographs were taken of each logger location 3. Each site was revisited several times through 2015-2017 and native and non-native aquatic species were recorded. 4. The drainage area (or watershed size) for each logger was calculated in ArcGIS. 5. The land use upstream from the logger was assessed by calculating the percent urban, percent agriculture, percent open space, percent residential, and percent commercial/industrial. 6. Temperature and Conductivity were collected from loggers and graphed. Future work will include continued logging and graphing of temperature and conductivity, continued survey of the sites for native and non-native aquatic species, and statistical analysis

Project groups


Project Group: Urban Runoff Studies

Project protocol

Name: Robust, low-cost data loggers for stream temperature, flow intermittency, and relative conductivity

Description: Water temperature and streamflow intermittency are critical parameters influencing aquatic ecosystem health. Low-cost temperature loggers have made continuous water temperature monitoring relatively simple, but determining streamflow timing and intermittency using temperature data alone requires significant and subjective data interpretation. Electrical resistance (ER) sensors have recently been developed to overcome the major limitations of temperature-based methods for the assessment of streamflow intermittency. This technical note introduces the STIC (Stream Temperature, Intermittency, and Conductivity logger); a robust, low-cost, simple to build instrument that provides long-duration, high-resolution monitoring of both relative conductivity (RC) and temperature. Simultaneously collected temperature and RC data provide unambiguous water temperature and streamflow intermittency information that is crucial for monitoring aquatic ecosystem health and assessing regulatory compliance. Wi

Project Data - Online Map

Project focus

Project type: Monitoring

Target species: California Treefrog, goldfish, largemouth bass, Pacific Chorus Frog--TREEFROG

Investigator: Robert Fisher

Main implementing entity: U.S. Geological Survey

Partner: San Diego Management and Monitoring Program

SDMMP lead: Emily Perkins

Study lead: Chris Brown

Strategic elements

MSP Objectives and actions:ALTHYD-1

Budget year: FY15-16; Work plan objectives number: 2.1

Files and Documents

2019 Amphibian IBI and Hydrological Impact Score

Author(s):Fisher, Robert N.

2020 Aseasonal Flow and Associated Nonnative Species in San Diego: Data Summary

Author(s):Brown, Chris; Perkins, Emily; Hitchcock, Cynthia J.; Aguilar Duran, Angelica; Guerra Salcido, Omar ; Watson, Elise; Fisher, Robert N.

2020 Draft Final: Associations Between Arroyo Toads, Nonnative Species, Drought, and Impervious Surfaces in San Diego County

Author(s):Brown, Chris; Perkins, Emily; Hitchcock, Cynthia J.; Aguilar Duran, Angelica; Grolle, Lizzie; Watson, Elise; Fisher, Robert N.

2019 Effects of drought on aquatic biodiversity and the effect of landscape-scale urbanization on aseasonal flow

Prepared by:San Diego Management and Monitoring Program; U.S. Geological Survey, Western Ecological Research Center

2018 Longevity and population age structure of the arroyo southwestern toad (Anaxyrus californicus) with drought implications

Author(s):Brehme, Cheryl; Fisher, Robert N.; Hathaway, Stacie; Hovey, Tim; Stokes, Drew; Warburton, Manna