Aquatic Long-term Monitoring

measurement collecting

SPU staff collect numerous measurements within selected stream reaches.

SPU is implementing a long-term aquatic habitat research and monitoring program to measure the overall ecological response of the aquatic systems in the watershed to HCP management activities and inform adaptive management.

In this program, SPU is monitoring stream health, documenting recovery from past water supply and land management operations, evaluating the success of aquatic habitat restoration projects, and identifying possible impacts of the City's operations on stream ecosystems. Long-term aquatic habitat monitoring will utilize data collected from Permanent Monitoring Reaches (PMRs), using long-term aquatic monitoring protocols established by SPU staff.

Since stream reaches having channel gradients less than 4% (termed response reaches) are generally the most biologically active and most susceptible to changes in the inputs of wood, water, and sediment, only response reaches are sampled. In order to ensure that sampling sites are spatially well-distributed, representative, and randomly selected, a “master sample” of response reaches was generated using a geographic randomized tessellation system (GRTS) algorithm.

Using a 5-panel design with five sites per panel, two panels (or 10 sample sites) are visited each year. Sites are revisited two years in a row with three years off before the next revisit.

We are using the following physical habitat indicators to assess aquatic health and track the effects from the City’s operations on the aquatic environment: stream temperature, pool frequencies and residual depths, large woody debris frequency and volume, and surface particle size distribution.

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