Summary of Diver Assisted Suction Harvesting Efforts. Lake Ellwood Florence County, WI

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Lizbeth Parsons
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2527 Lake Ottawa Road Iron River, MI 49935 906.284.

1 2527 Lake Ottawa Road Iron River, MI Summary of Diver Assisted Suction Harvesting Efforts Lake Ellwood Florence County, WI 2015 WDNR Mechanical Harvesting Permit Annual Report Permit ID NO M Date: Submitted To: Lake Ellwood Association and Wisconsin Department of Natural Resources Submitted By: Many Waters, LLC 2527 Lake Ottawa Road Iron River, MI Contact: Bill Artwich: Barb Gajewski: Lake Ellwood, Florence County, WI DASH 2015 Page 1

Introduction The Lake Ellwood Association solicited the services of Many Waters, LLC to use Diver Assisted Suction Harvesting (DASH) to manage for hybrid watermilfoil (HWM) on Lake Ellwood located in

2 Introduction The Lake Ellwood Association solicited the services of Many Waters, LLC to use Diver Assisted Suction Harvesting (DASH) to manage for hybrid watermilfoil (HWM) on Lake Ellwood located in Florence County, WI. DASH is a mechanical process and requires a mechanical harvesting permit (Form (R 3/04)) from the Wisconsin Department of Natural Resources (WDNR). The 2015 WDNR Permit ID is NO M. Dive Methods While using DASH, a diver typically will begin by locating the invasive plant such as Eurasian watermiloil or in the case for Lake Ellwood hybrid watermilfoil from the surface, and then descend next to the plant while simultaneously lowering the nozzle. Divers works along the bottom by using fin pivots, kneeling on the bottom or hovering above the bottom at a distance where the root mass of the plant is within hands reach. Lake Ellwood s organic marl substrate does pose some difficulties for the diver compared to other lakes. Due to the unconsolidated nature of this organic marl substrate, divers do not have as much leverage removing roots from the sediment. Some leverage is gained however, by holding onto the handle of the nozzle. The diver will either feed the top of the plant into the hose first and then uproot the plant or uproot the plant and feed it root wad first into the hose. It is very important that the diver shake as much sediment from the root wad before getting the root wad near the nozzle. Shaking the root wad away from the nozzle helps maintain visibility for the diver and minimizes debris and sediment in the holding bins. The diver carefully observes plants fed into the nozzle for possible fragments. Fragments are caught by hand and fed into the nozzle. Work sites that have dense monotypic beds of EWM, the initial DASH efforts are quite simple. The diver will descend adjacent to the bed and begin hand pulling or harvesting systematically across the bed to dismantle the bed. Once the majority of the bed is removed, a more systematic approach follows to target remaining clustered, scattered or outlier plants in the work site. As part of our method for covering a work area while using DASH (or divers alone), a grid pattern is used. A diver will start at either the port or starboard side of the boat and work to and from the boat perpendicular to the direction the boat is facing. For example, with the boat facing north and the diver starting on the port side, the diver begins by heading west. The diver will continue to work perpendicular to the boat until reaching the end of the suction hose. The diver then works back to the boat on a new transect line. Distance between each transect is dictated by visibility, density of EWM, and obstructions. The diver may need to move to a new portion of the work area if visibility is reduced due to sediments suspending from the dislodged root wad. This process is repeated on the opposite side and in front of the boat. Depending on the site, once the diver has adequately covered the area, which the suction hose can reach, they will signal the deckhand to let out more anchor line or determine that the boat needs re-positioning. Lake Ellwood, Florence County, WI DASH 2015 Page 2

3 Once plants reach the surface, a hose dispenses the plant material into a series of screened bins located on the deck of the boat. These bins capture plants and allow water to drain out back into the lake. Plants on deck are sorted into two categories: the targeted invasive plant and native vegetation. A wet weight of both the invasive plant and all native species combined is taken. Plants are placed in sealable containers or bags for transport to the dumping site. The dumping site is a pre-determined site upland, away from any water body. Figure 1: 2015 DASH Work Areas (Onterra, 2015) Lake Ellwood, Florence County, WI DASH 2015 Page 3

4 Summary Table 1: Daily Summary of DASH Efforts Date Location Ave. Depth (ft) DASH Boat Location Lat (NAD 83) Long (NAD 83) Working Direction Dive Time (hrs) EWM (lbs*) Incidental Native Plant Harvest (lbs*) Incidental Native Plant Harvest (%) Total (lbs*) 7/22/2015 D-14 located in C NNW % /23/2015 D-14 located in C W & SW % /23/2015 D-14 located in C WSW % /24/2015 D-14 located in C SSE % /27/2015 D-14 located in C ESE to S % /28/2015 D-14 located in C SE & S % /29/2015 D-14 located in C SW to SE % /30/2015 D-14 located in C NNW % % (Average) Lake Ellwood, Florence County, WI DASH 2015 Page 4

5 Daily Log Initial DASH efforts focused on D-14, an area of denser HWM located along the northwest portion of C-15. The strategy was to work from D-14 southeast to C-14, removing larger colonies nearing the surface. After completion of this area (C-15), DASH efforts would shift focus to B-15. All seven days of DASH efforts took place along the northwest portion of C-15 in and around D-14. No efforts took place within B-15. July 22 nd 2015 Weather- Sunny, 75 degrees, light N-NW wind We motored a quick pass around D-14. Few outlying plants were observed, however for the most part a very distinct core area of HWM existed. Divers worked systematically north to south taking the outer HWM plants on each pass. Four and a quarter diver hours removed 449 pounds of HWM. Incidental harvest of native plant species remained nominal, similar to previous DASH efforts. July 23 rd 2015 Weather- 80 degrees, Sunny, light W-SW wind Positioned along the northern edge of C-15, five and a half hours of diving removed 584 pounds of HWM. Incidental harvest of native species remained similar compared to the previous days efforts. July 24 th 2015 Weather- 70 degrees, overcast, SW wind 5-10 mph DASH work continued on the north side of the D-14 area. Diving conditions remained good except for the overcast skies, which can reduce visibility; however, it did not have much effect on the diver this particular day. Systematic back and forth passes across the dense area of HWM was the method used to harvest pounds of HWM in four hours of diving. July 27 th 2015 Weather- Sunny, 85 degrees, light and variable wind Weather and water clarity conditions remained excellent as we continued harvesting on D-14. Five hours of diving, removed pounds of HWM. Incidental harvest of native plant species remained similar to previous days and included water celery (V. americana), sago pondweed (S. pectinatus), slender naiad (N. flexilis) and Illinois pondweed (P. ilinoensis) however primarily consisted of water celery. July 28 th 2015 Weather- Mostly Sunny, 74 degrees, S-SW wind 5-10 mph DASH efforts continued along the northern portion of D-14. Conditions were good and systematic passes across the dense area of HWM was the method used. Five and three quarter hours yielded pounds of HWM. Brenda Nordine from the WDNR and her field technician made a field visit. July 29 th 2015 Weather- Sunny, 70 degrees, W-NW wind We continued to harvest along the south central portion of D-14 but the strong winds made holding position difficult. All anchors on board were used with longer leads than normal. The high winds made thing difficult for the deckhand but had little effect on the diver. Five and a quarter dive hours harvested 564 pounds of HWM. Lake Ellwood, Florence County, WI DASH 2015 Page 5

6 July 30 th 2015 Weather- Sunny, 65 degrees, N-NW wind mph The wind switched to a more northerly direction from the previous day making a longer fetch and subsequent larger waves. Initial positioning was a struggle, however, once got setup the boat held position fine. Four and a quarter dive hours removed 544 pounds of HWM. Lake Ellwood, Florence County, WI DASH 2015 Page 6

Management of Hybrid Watermilfoil (Myriophyllum sibericum x spicatum) using Diver Assisted Suction Harvesting

2527 Lake Ottawa Road Iron River, MI 49935 906.284.2198 Management of Hybrid Watermilfoil (Myriophyllum sibericum x spicatum) using Diver Assisted Suction Harvesting Lake Ellwood, Florence, WI - 2014 Final