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Composite samples will be taken by automatic stormwater samplers (American <br /> Sigma Model 900 MAX ) . Each automatic sampler will take lowmweighted <br /> composite samples ( Le , the amount of sample collected is proportional to the <br /> flow rate ) . The composite sample containers will be thermally preserved during <br /> the collection process , the composite jug will be stirred and siphoned into lab- <br /> supplied bottles ( in the field ) that have been properly chemically p eserved , and <br /> the samples will be transported to the laboratory on ice in order to ensure proper <br /> preservation . <br /> Each automatic sampler will be activated based on a rise in water depth in the <br /> pond . Once activated , the samplers will take flow-weighted samples at fifteen <br /> minute intervals , for twenty-four hours . However , if the lake depth drops to a <br /> predetermined level within four hours after initiating sampling , the sampler will <br /> shut off, since this will indicate a non -significant rainfall event . The sample <br /> suction points are located near the influent pipe or effluent weir (within ten to <br /> fifteen feet ) , as applicable , and are approximately mid -depth in the water column . <br /> Field samples (Temperature , pH , Salinity , and Dissolved Oxygen ) will be taken in <br /> the vicinity of each sample suction point . Proposed field instrument are : <br /> ( 1 ) YSI Environmental 4 YSI 63 pH /Salinity/Conductivity emperature <br /> Instrument , and <br /> (2 ) YSI Environmental 4 YSI 55 Dissolved Oxygen Instrument . <br /> Reporting . <br /> A component of this project involves developing a detailed and systernatic record - <br /> keeping system to report water quality monitoring activities . The intent is to gauge the <br /> overall effect of the stormwater improvements . Water samples from thepond ' s influent <br /> and outfall will be periodically collected , tested and analyzed to develop trend curves . <br /> Bimonthly and semiannual review reports will be produced as necessary . A final report <br /> will be provided when sampling is complete . <br /> 4 <br /> F :\Public Works\KeithM\Stormwater Projects\Gifford East\Water Quality Monitoring Program\Quality Assurance roject Plan\Gifford <br /> Water Quality Sampling Plan . doc <br />