**The title, authors, and abstract for this completion report are provided below. For a copy of the completion report, please contact the GLFC via e-mail or via telephone at 734-662-3209**
Hydrodynamic Model Study: Lampricide Plumes in Lake Champlain Near the Lamoille River
Roger C. Binkerd
664 Hills Point Road
Charlotte, VT 05445
The Lake Champlain Fish & Wildlife Management Cooperative (the Cooperative) has proposed a lampricide treatment in the Lamoille River, a tributary to Lake Champlain, to control a recently discovered population of sea lamprey larvae. As required by the State of Vermont permit process, the Cooperative needs to provide information regarding potential lampricide exposure to Lake Champlain water users. To provide this information the fate of lampricide as it enters, distributes, and decays in Lake Champlain is required. The Cooperative will use this information to delineate zones in Lake Champlain where the public would be advised not to use lake water until concentrations dilute and degrade to below a threshold concentration. The Cooperative contracted with BINKERD ENVIRONMENTAL to provide predictions, using mathematical modeling, of lampricide distribution and concentration in Lake Champlain.
BINKERD ENVIRONMENTAL selected Delft3D-FLOW, a generalized hydrodynamic model by WL/Delft Hydraulics. The objective is achieved using two parallel analysis procedures. In the first procedure, TFM distributions are simulated for uniform and steady winds using various combinations of wind direction (NNW, NNE, SSE, or SSW), wind speeds (2 and 8 m/s) and river discharges (28 and 48 m3/s). Results of simulations with steady winds indicate that plumes are larger for an increase in river discharge and/or wind speed. Steady winds from the north resulted in more rapid dilution compared with steady winds from the south due to shallow depths north of the Lamoille River adjacent to the Sandbar Causeway compared with deeper water south of the river. In the second procedure, five dates in October from 1999 to 2005 are selected randomly as start times for simulations using real, variable winds. Wind data are from a weather station at Colchester Reef, a location in Lake Champlain near the study area.
The time to achieve a TFM concentration of less than 20 ppb everywhere in the study area for the variable wind simulations is 41-94 hours; the longest duration correlates with lowest winds. Composite plumes showing maximum concentrations from steady winds at 8 m/s from four directions are quite similar to the composite results from the variable wind simulations. The 20 ppb TFM contour extends westerly from near Robinson Point, to just north of the opening in the Sandbar Causeway and extending from the west and to east shores of the Inland Sea, and south past the Lamoille River to near Malletts Head.