Environmental Monitoring Program

Physical water quality parameters are measured using YSI EXO2 multi-parameter sonde with sensors for water temperature, dissolved oxygen, specific conductance, pH, turbidity, chlorophyll fluorescence.

Water for nutrient samples are collected at a depth of approximately 3 feet using a Van Dorn sampler (van stations), a submersible pump or a flow through system (vessel stations). Samples are analyzed by DWR’s Bryte Laboratory for chloride, chlorophyll a, pheophytin a, nitrate, nitrite, nitrogen, organic carbon, organic nitrogen, ortho-phosphate, phosphorus, silica, total/dissolved solids, and total/volatile suspended solids.

Phytoplankton samples are collected alongside discrete nutrient samples with a submersible pump from a water depth of one meter (approximately three feet) below the water surface. Samples are stored in 50-milliliter glass bottles with 2mL of Lugols solution to act as a stain and preservative. Currently, phytoplankton samples are analyzed by BSA Environmental, Inc.  Phytoplankton are identified to the lowest taxonomic level possible using the Utermöhl method and APHA standard methods (Utermöhl 1958, APHA 1998).

The project uses three types of sampling gear: a mysid net (505 um mesh), a Clarke-Bumpus net (160 um mesh, targets adult and juvenile copepods, and cladocerans), and a pump (43 um mesh, targets adult and juvenile cyclopoid copepods of the genera Limnoithona and Oithona, copepod nauplii, and rotifers). The zooplankton tows are conducted obliquely through the water column for 10 minutes. A total of 19.8 gallons of water are sampled vertically through the water column for the pump samples. All samples are preserved in 10% formalin with Rose Bengal dye to aid in laboratory processing.

Fact sheets on how zooplankton can be incorporated into resource management.

• Fact sheet for managers (PDF)
• Fact sheet for zooplankton researchers (PDF)

A Hydraulic winch and Ponar dredge are used to collect four replicate grabs at each of the ten benthic stations. The contents of each grab sample are washed over Standard No. 30 stainless steel mesh screen and carefully washed with a fine spray to remove as much of the substrate as possible. All material remaining on the screen after washing is preserved in a solution of approximately 10% buffered formaldehyde containing Rose Bengal dye for laboratory analysis, followed by transfer to 70% ethanol for long-term storage. An additional Ponar grab sample is taken and 500 ml of sediment is collected for analysis at the DWR Soils Laboratory.