NPS: Nature&Science»Networks: San Francisco Bay Area Network»Monitoring

Freshwater Dynamics

Streamflow characteristics offer some of the most appropriate and useful indicators for assessing river ecosystem integrity over time. The streamflow characteristics of a watershed reflect vegetation type, land characteristics and human use, the weather and climate conditions, and soil characteristics. Streamflow characteristics are extremely sensitive to human actions. Common human activities such as increasing impervious surface area in watersheds change the timing and magnitude of peak runoff events resulting in “flashy” systems. Hydrologic variation in turn shapes the biotic diversity within river ecosystems by controlling critical habitat conditions within the river channel, the floodplain, and hyporrheic zones. Stream hydrology data provides key “support” data for existing NPS vital sign protocols including stream threatened and endangered (T&E) species and fish assemblages, T&E amphibians and reptiles, wetlands, and riparian habitat.

Monitoring Objectives

Monitor the variability and long-term trends in stream flow using fixed water stage recording stations by producing annual mean daily and monthly discharge estimates.

Monitor the frequency, magnitude and duration of peak flow events at fixed water level monitoring stations by producing peak and daily summaries of stage height and discharge.

Monitor the frequency, magnitude and duration of unnatural or extreme low water/low flow events in stream reaches known to support threatened and endangered aquatic species in the dry season at GOGA, PINN, and PORE.

Reports and Resources

Contact Darren Fong for any past stream flow reports

Contact Information

Darren Fong
GOGA Aquatic Ecologist
415-331-8716

Link to Intranet Page (NPS only)

Monitoring Protocol

Nine stations were selected for monitoring including two within GOGA, one at The Presidio, two at PORE, one at JOMU, and three at PINN.
Primary monitoring tasks include obtaining stream flows; developing hydrographs and other data analysis tools for each stream gauge; downloading, maintaining, and calibrating hydrologic equipment; and refining the methodology for these tasks. Duties also include conducting literature reviews on monitoring parameters, instrumentation, and protocols for hydrologic monitoring.
Flow measurements will be obtained monthly during the summer (in conjunction with station maintenance and downloading) and at regular intervals during winter storms to maintain the stage-discharge rating curve. Current meters at most sites will be used to obtain discharge following the USGS standard protocol (Rantz 1982). At PRES, a calibrated flume will be used to obtain discharge. Water level monitors (pressure transducers) will be utilized as well as staff and crest gages. Data collection and management will focus on the seven automated stream gauging stations within the network. However, as the monitoring plan is implemented and streamlined there will be opportunities to include data from locations without automated stream gages (e.g., staff gages at water quality monitoring sites and fish traps).
Additional data may be obtained from groups withdrawing surface or groundwater from monitored streams (e.g., Redwood Creek) in order to understand streamflow dynamics.

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