The NSW MARITIME AUTHORITY has released its "Boating Plan for Tweed Estuary" . Released on Wed 9 Aug 2006.

The Boating plan does make some interesting reading and has provided stats about PWC use and enforcement action  taken during the survey period.

Examples and quotes are shown in the report include;

TABLE 5  VESSEL ACTIVITY 2004
Activity Vessels %
CRUISING         105 37.8%
FISHING            70 25.3%
MOORED             4 1.6%
SAILING              1 0.4%
SKIING              43 15.5%
WAKEBOARDING  18 6.7%
PWC                 35 12.7%
Grand Total                277 100.0%

It should be noted that PWC accounted for 25.1% of all infringements issued over the 1998-2004 period..

As 81% of all personal water craft on the Tweed are registered in QLD, it is imperative from a safety point of view, that the operators of these craft are familiar with NSW legislation. Maritime will target a number of education campaigns towards QLD PWC users aimed at improving compliance with NSW regulations.

Quote
Decibel Limit:
"In line with the principals of the above legislation NSW Maritime will introduce a 75dB(A) noise restriction in selected areas where riverside residents reside close to a narrow section of the estuary, eg. Tumbulgum Village and Murwillumbah.
The 75dB(A) noise restriction will be measured in accordance with the Authority’s noise testing procedures and will be measured at 30 metres."

Full public documents are placed on the Waterways web page.

http://www.maritime.nsw.gov.au/index.html