The Borel Project Study Plan for sampling benthic macroinvertebrates in the Kern River was developed in consultation with the State Water Resources Control Board, the California Department of Fish and Game, the Sequoia National Forest and other interested parties. The Plan conforms to CDFG’s California Stream Bioassessment (CSBA) protocols. This report discusses the objectives and methods of the Study Plan and describes how the results will be reported.

The objectives of the Study Plan are as follows:

• to assess ecosystem integrity of the Borel reach of the Kern River using CSBA community metrics,
• to evaluate food resources for fish in the Borel reach, and
• to assess whether or not the Kern River biota near the tailrace is affected by the Borel Powerhouse discharge.

Sampling will be conducted at the following seven stream reaches in the study area:

1. North Fork Kern River upstream of Lake Isabella,
2. Borel diverted reach within a mile of the dam,
3. Borel reach two to three miles downstream of the dam,
4. Borel reach four to five miles downstream of the dam,
5. Borel diverted reach within a mile upstream of the Borel Powerhouse,
6. about 1 mile downstream of the Borel Powerhouse, and
7. immediately downstream of the Borel Powerhouse tailrace.

The objective for sampling below the tailrace is to determine if the Borel Powerhouse discharge has any significant local effect on the river’s biotic community. The discharge affects stream depths and current velocities of habitat near the tailrace and may affect water chemistry because of algicide treatment of the Borel Canal. Evaluating effects of the algicide treatment will be specifically addressed in a separate study plan. The objective for sampling above Lake Isabella is to provide a control site that is relatively unaffected by human impacts on flow or potential influences of the reservoir.

The specific locations sampled within the first six stream reaches listed above will be selected following the CSBA protocol for "non-point source sampling". This protocol is used to assess conditions within an entire stream section. The protocol calls for selecting stream locations with productive riffle habitats. At least five riffles will be marked along the stream channel in each stream reach and three of the riffles will be randomly selected for sampling. A sampling transect will be selected in each riffle by placing a measuring tape along the bank of the entire riffle and randomly selecting one of the meter intervals along the upstream third of the riffle. Modifications to this protocol may be necessary if suitable riffle habitat is limited.

The specific locations sampled for the final stream reach, downstream of the Borel Powerhouse tailrace, will be selected following the CSBA protocols for "point source sampling". This protocol is used to assess potential point sources of pollution. At least one riffle will be selected just downstream of the tailrace and one or more riffles will be selected just upstream of the tailrace. The upstream riffle would probably be one of the riffles selected in the fifth sampling reach listed above, i.e., the Borel diverted reach within a mile upstream of the Borel Powerhouse. Three sampling transects will be randomly selected in each of the selected riffles.

For both sampling protocols, three sites will be sampled along each sampling transect and the material collected from the three sites will be combined into one composite sample. If the substrate and structure of the stream channel along the transect is fairly uniform, the three sampled sites will be near each side and in the center of the stream. If the substrate and channel structure are not uniform, the selection of the three sampled sites will seek to represent the variation present.

A kick sample of 2 to 3 minute duration will be collected at each site along each transect. A pair of biologists using a 40-inch x 40-inch Zo Seine (0.5-mm mesh) will conduct sampling. During sampling, one biologist will hold the net immediately downstream of a 2-foot x 1-foot patch of riffle substrate, while the other biologist disturbs the substrate. Immovable substrate will be rubbed in place to wash invertebrates free of the surface. After combining the material from the three sites in each transect into a jar, water will be drained from the jar and replaced with a 95 percent ethanol solution to preserve the sample.

Water temperature, dissolved oxygen, pH, electrical conductivity and standard physical/habitat characteristics will be measured in each sampling reach.

All locations will be sampled during the same 5-day period during late February 2001. The sampling will be conducted during daylight hours.

A total of at least 21 samples (three composite samples per sampling station) will be obtained from the Borel Project CSBA sampling program. All of the samples will be processed and enumerated by specialized taxonomic laboratories. The laboratory results will be used to compute the CSBA community metrics, which will be used to assess the condition of the river’s macroinvertebrate community, food resources for the fish, and ecosystem integrity.

Twenty percent of the samples (five samples) will be randomly selected and will be processed by a lab selected by the Department of Fish and Game for QA/QC purposes.

Following completion of the sample processing, a draft technical report of the results will be prepared. The report will provide a table listing numbers of each taxa collected and a discussion of the QA/QC results. Other tables and graphs will present the computed community metrics for each sampling station. A summary table will give the water quality results and habitat characteristics for each station. The report will also provide a comparison of the results with CSBA results from other Sierra streams and will include a discussion of the significance of the results with regard to ecosystem integrity of the Borel Reach of the Kern River, the food resources for fish in the reach, and any local impact of the Borel Powerhouse discharge.

The fieldwork will be completed by April 1, 2001. Assuming the taxonomic and QA/QC labs can complete sample processing in a timely manner, the results will be available by May 15. If the lab results are completed on time, the draft report will be made available about July 1 and a technical meeting to discuss the results will be held about July 15, 2001.

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