PUBLIC CONSULTATION: WAKESURF ACTIVITIES – LAKE ST-PIERRE
1 PROBLEM SPACE
The restrictions on the use of the municipal ramp (2014) have had no effect on the number of wakeboats and on the popularity of wakesurfing… Users have access to private ramps Wakesurfing activity is dominated by a minority of lake St-Pierre property owners (~23 out of +400) Over 115 complaint letters addressed to mayor in fall 2020 ! Wakesurfing dominates over all other activities of lake St-Pierre… Canoe capsizing, kayaking (dangerous outside the morning hours) Violent rocking of boats/docks, broken docks, fallen children/pets Dirty water unsuitable for swimming, pumps blocked Codes of ethics /nautical guide / awareness campaigns published by the municipality are ignored 2 PROBLEM SPACE (CONT’D)
Wakeboat horsepower is huge (200-500 HP) … and continues to increase year over year
All of this horsepower is dedicated to the generation of waves, and not to propel the boat (since wakesurfing is conducted at a speed of 11.2 mph = 18 km/h) Wave action on shorelines is equivalent to > 100 – 200 H.P. Significant shoreline erosion caused by wakesurfing waves Wave amplitudes ~ 20x greater than those caused by winds (0-20 cm VS 1-2m) Erosion is deposited onto lake bottom leading to accelerated aging of lake Uprooted waterfront trees and other vegetation Loss of up to 13’ of shoreline reported by one owner!
3 PROBLEM SPACE (CONT’D)
Shaking/mixing/suspension of sediments by wave action - conditions conducive to the growth of milfoil more milfoil Most shoreline consists of organic layer of sediments approx. 2’ – 3’ in thickness Embedded phosphates and other organic mixing of materials are released promoting sédiments more
growth of milfoil erosion
winter winter
Other organic materials are released summer Filthy water – unsuitable to swimming waves
Spread of invasive species more (such as Eurasian milfoil, mussels…) via sediments wakeboat ballasts from lake to lake Dangerous waves for pets/seniors/children/small boats) Destructive waves (to shoreline property/installations) 4 PROBLEM SPACE (CONT’D) Mixing / Shaking of Bottom Sediment Layer
milfoil zone 1’
2’ < depth < 15’ 15’
sediment layer thickness > 2’
5 PROBLEM SPACE (CONT’D) Mixing / Shaking of Bottom Sediment Layer
wakesurf waves > 2’ shaking/mixing of sediment layer Promotes suspended sediment milfoil growth Release of phosphor and other organic matter
6 PROBLEM SPACE (CONT’D) Coalition Navigation (https://coalitionnavigation.ca/fr/)
According to scientific studies…
Wakeboat waves must travel a distance of 300 metres before losing their power (paper published by l’UQAM)
Effects of wakeboat waves act up to 5m deep (paper published by l’U. Laval (2015) - Dr. Sébastien Raymond
A wakeboat requires a 600 meter channel and a water depth of 5 meters to avoid negative impacts on the environment NOTE: Average Wakeboat HP has increased since study !!! 7 LAKE ST-PIERRE Navigable area: ~ 3 km2 Shoreline1: ~ 25 km 1buffer zone of 30m
Note: For comparison, a circular lake would offer 4x more navigableA surface area milfoil per km of shoreline
virtually all of lake Large waves don’t have St-Pierre’s shoreline a chance to dissipate is exposed to because the lake wave action is very narrow (~300m) from wakesurfing
8 LAKE ST-PIERRE
Lake St-Pierre is naturally protected from winds
no waves
NO EROSION
9 LAKE ST-PIERRE lake St-Pierre is protected from winds
shorelines have NEVER been exposed to waves a fragile lake when subjected to 20X NO NATURAL wakesurfing waves
EROSION 10