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10 <br /> <br /> <br />4.0 WATER QUALITY MONITORING PLAN <br /> <br />4.1 OBJECTIVE <br /> <br />The objective of the Water Quality Monitoring Plan is to document representative water quality <br />conditions in the receiving/treatment area (the area receiving aquatic pesticides) and the <br />adjacent untreated water both prior to (pre-treatment) and after (post-treatment) the application <br />of aquatic pesticides. The resulting water quality data can then be used to evaluate the potential <br />impacts on beneficial uses from the pesticide applications. This data can also be used to <br />develop, evaluate, and refine Best Management Practices (BMPs). <br />4.2 SAMPLING FREQUENCY <br /> <br />Pre- and post-treatment monitoring of dissolved copper and/or diquat levels in the water column <br />will be conducted during the April through September season of the aquatic pesticide <br />applications. State regulations require that pre- and post-treatment sampling shall be conducted <br />for every pesticide application events/sites for up to 6 consecutive samplings under required <br />concentrations of receiving waters. At such time when 6 consecutive samplings meet or are <br />under required concentrations, sampling will continue with a frequency of once (1) per year for <br />the deration of the permit period. If during this annual sampling concentrations exceed limits for <br />receiving waters 6 consecutive samplings will have to meet or be under required concentrations <br />for the frequency to revert back to an annual basis. The State uses the term, "application sites" <br />instead of application events, and individual treatment sites within a large body of water would <br />apply if there were only two or three treatments for the season. In a large and complex body of <br />water that may have several spot treatments in a given day and be treated several times a month <br />throughout most of the growing season, the term "application event" might encompass all the <br />treated sites on a given day and a representative site chosen for sampling during that application <br />event. <br /> <br />4.3 SAMPLING LOCATIONS <br /> <br />The following descriptions of sampling locations are taken from the description of the <br />Monitoring and Reporting Program, Water Quality Order No. 2013-0002-DWQ, with an <br />interpretation of each requirement relative to Redwood Shores Lagoon shown in italics. <br /> <br />1. Background Monitoring - Background monitoring samples shall be collected upstream at the <br />time of the application event or in the application area just prior to (up to 24 hours in <br />advance of) the application event. (pre-treatment) For Redwood Shores Lagoon, this will be <br />within the treatment are, typically 50 feet inside the boundary of the treatment zone. For the <br />sake of efficiency, sampling just prior to the application event will likely be most convenient <br />at Redwood Shores lagoon as this will allow it to be combined with the Event Monitoring. <br /> <br />2. Event Monitoring - Event monitoring samples shall be collected immediately downstream of <br />6.3.A. - Page 175