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CLP in Demontreville–Olson (Washington Co, MN) – April+June 2024 <br />© 2024 – Freshwater Scientific Services, LLC Page 2 of 5 <br />... <br />Purpose of Survey <br /> <br />This report includes survey results from an April survey of Lake Demontreville, and a June <br />survey of Olson Lake. These surveys were conducted to locate and delineate areas of curlyleaf <br />pondweed (CLP) in the designated portions of Lake Demontreville (#82-0101) and Olson Lake <br />(#82-0103). This information will help to guide CLP management in the lakes and is required as <br />a part of the DNR permitting process for herbnicide treatments. <br /> <br /> <br /> <br /> <br /> <br />CLP Delineation Surveys <br />We surveyed designated portions of Lake Demontreville on April 5, 2024 (pretreatment), and <br />portions of Olson Lake on June 4, 2024 (peak abundance, no treatment). During these surveys, <br />we navigated a meandering path over the designated search areas while using a combination <br />of surface observations, sonar readings, and rake tosses to locate and delineate areas of CLP <br />growth. When we encountered CLP plants, we marked the location, recorded the water depth, <br />and rated the density of the growth using visual and rake density scores as described in the <br />table below. <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br />For rake samples, we dragged a sampling rake over approximately 10 square feet of lake <br />bottom and recorded the CLP density based upon the number of plants (stem count) retrieved <br />on the rake. The recorded water depths and density scores were linked to the appropriate GPS <br />locations and then mapped using desktop GIS software. <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br />Survey Method <br /> <br />Score Visual Rake <br />1 Light / Solitary plants 1-2 stems <br />2 Moderate / Scattered dense patches 3 to 9 stems <br />3 Dense / Uniform dense growth 10+ stems <br />