National Park Service

Sierra Nevada Network (SIEN)

River Monitoring

Hydrologists taking stream measurements at Devils Postpile National Moument
Hydrologists taking stream measurements at Devils Postpile National Moument. Photo by Alice Chung-MacCoubrey.

River Monitoring Briefs

River Protocol Documents

Links

For more information contact: Andi Heard

Rivers Monitoring brief

River Hydrology monitoring in the Sierra Nevada Network parks resource brief
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Importance & Issues

Hydrology, the distribution and movement of water and its interactions with the surrounding environment, in the Sierra Nevada is a critical component of both the parks' ecosystems and the larger California water infrastructure.

The Sierra Nevada Network (SIEN) parks contain the headwaters of seven major river watersheds (Figure 1). Most of the parks' land area is mid- to high-elevation, where snow is the major form of precipitation. As the winter snowpack melts in spring and summer, it supplies water to park ecosystems through dry summer and early fall seasons. Water from Sierra Nevada snowmelt also flows down rivers and streams to serve as a primary source of water for domestic, commercial, and agricultural use throughout California.

Major watersheds in the Sierra Nevada Network parks. Figure 1. Major watersheds in the Sierra Nevada Network parks.

In the coming decades, climate change will have profound effects on water resources and associated ecosystems in the Sierra Nevada. Rising air temperatures are one of the most widely observed trends that affect hydrology. The Sierra Nevada has warmed 0.5 to 1.5o C over the last 50 years. Air temperature influences the form in which precipitation falls, and warmer air temperatures raise the elevation of the rain-snow transition zone. In the mountains, as this zone moves upward, more precipitation falls as rain rather than snow. Changes in precipitation type and timing will result in a reduced snowpack, earlier snowmelt runoff, and longer and drier summers with less water available during the months it is most needed. Increased flooding and erosion and lower summer flows will threaten water quality and aquatic life.

Altered fire regimes also influence hydrology. Fire suppression policies have reduced fire frequency in much of the parks' landscapes. Lack of fire can reduce stream flows. Less frequent but higher severity wildfires can change hydrologic patterns by increasing flooding, erosion, and sediment input. Fire also influences water quality by increasing the input of nutrients to aquatic systems.





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Monitoring Objectives and Approach

This streamflow gaging station on the Marble Fork of the Kaweah River In Sequoia National Park has operated since 1992. The station measures water level (stage), temperature, and conductivity every hour. This streamflow gaging station on the Marble Fork of the Kaweah River In Sequoia National Park has operated since 1992. The station measures water level (stage), temperature, and conductivity every hour.

Sierra Nevada Network and Park staff evaluated existing stream gaging stations and selected 14 gages to include in this monitoring project. Eleven of these gages are managed entirely by cooperators in other agencies and organizations, and three receive some financial or operational support from SIEN. The objectives of the river hydrology monitoring project are to:

  1. Detect long term trends in timing and volume of streamflow using fixed, continuous, water stage recording stations at existing streamgages in selected major watersheds of the SIEN, and

  2. Record, measure, and/or calculate a set of specific hydrologic measures related to the timing and quantity of streamflow (e.g., stage, discharge, number of days to onset of snowmelt, measures related to low and high flows, and other parameters).

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Management Applications

Rainbow Falls, Middle Fork San Joaquin River, Devils Postpile National Monument. Rainbow Falls, Middle Fork San Joaquin River, Devils Postpile National Monument.

Data from this protocol will:

  • Contribute to the understanding of the effects of climate change on the hydrology of Sierra rivers.
  • Contribute to the understanding of flood dynamics.
  • Contribute to the understanding of the relationships between fire and hydrology and guide fire management decisions.
  • Inform park managers who oversee hydropower and other related licensing.
  • Inform managers so they may plan for short- and long-term changes in surface water dynamics and the effects of those changes on park resources such as wetlands, forests, and terrestrial and aquatic wildlife.
  • Inform parks so they are able to better define desired future conditions for long-term resource management planning.

Project Cooperators

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Last Updated: December 30, 2016 Contact Webmaster