Assessing the Impacts of Recreational Boating Activities on River Bank stability - M/BUS/226
MDFRC Technical Report
1 of 3 reports associated with project see (Impacts of Recreational Boating on River Bank Stability in the River Murray) and (Impacts of Recreational Boating on River Bank Stability: Wake Characteristics of Powered Vessels).
Recreational boat wakes have clearly been implicated in bank erosion in a wide variety of river types and sizes, both in Australia and internationally. Detailed studies of the rates of bank erosion and boat activity in river systems as different as the Gordon River (Tasmania), the Mississsippi River (USA), the Waikato River (NZ) and the Kenai River (USA) have all shown measurable impacts of recreational boats on the river bank stability. However even these studies have not always established the exact quantitative relationship between boat speeds, intensity or frequency of boat use, types of boats and the observable bank erosion. Studies have been conducted to develop predictive formulas for the size of wakes generated by a given boat size or speed; however these are not easily applicable in settings where there may be multiple boats operating at different speeds. Despite these limitations, in many places management responses have ensued and policies have been implemented, or are proposed, to limit boat speeds and otherwise minimize the impact of boat wakes. On the Murray River there have been few studies examining the role of boat wakes but all studies to date suggest that other processes, specifically the seasonal cycle in flow rates in this highly regulated river, may in fact be equally or more significant than recreational boat use.