An Okanagan Collaborative Conservation Program report on Kalamalka and Wood lakes found that lake bottom sediment contains bacteria, heavy metals, pesticide residues and hydrocarbons.
The boat impact study also found that boat propellers can stir up these sediments, re-suspending them in the water, where they can drift into drinking water intakes.
The report is due to be received by Vernon city council on Monday.
Growth in the Okanagan and increased boating activity generated a need for a comprehensive and scientific analysis for the potential impacts of motorized boating on water quality and environmental values, the report states.
The Districts of Lake Country and Coldstream, North and Central Okanagan regional districts, along with the Okanagan Similkameen lnvasive Species Society and OCCP collaborated on the study.
The report recommends recreational use should occur in locations that reduce risk to drinking water intakes and the environment, and that power boat corridors be designated away from shorelines, along with low-wake zones, and that spill safeguards and response plans be put in place.
The report also identified large waves from boats are damaging shoreline property through erosion, swamping floating bird nests, and destroying Kokanee salmon spawning habitat.