Tauranga – Mount: Dredging Versus Natural Processes, What’s Going On?
photos courtesy of Jerry Aubertin
A high degree of concern over degraded surfing conditions at the Mount – Papamoa surfbreaks over the last year or so has been directed to the Surfbreak Protection Society (SPS) via the local surfing community, many of whom have been surfing the area for decades.
Spurred on by this concern SPS have engaged the Regional Council and Port over monitoring of these surfbreaks, including Matakana Island, with regard to effects from port dredging activities.
At the Mount, what has been observed by local surfers is channels forming close to the beach and the disappearance of localised sandbars, with peaks forming out to sea, then fading or loosing steepness and the waves dumping on the shore.
The uncompleted artificial reef only contained half of the 6500 cu meters originally consented for, yet the areas surf lifesaving clubs continue to report 100% increase in rescues, it seems implausible that the effects of the reef would be the cause when depositing of dredge spoil has continued in this time frame.
Since May, SPS has been engaging Bay of Plenty regional Council and the Port with regard to what has been observed in regard to the areas surfbreaks, and the response has been generally supportive though the speed to set up a proper monitoring / analysis has not been to our liking, we have had a couple of hurdles to overcome;
The council expert has been away for a month, and we are awaiting his assessment of a technical memo provided on our behalf by eCoast marine and Consulting Ltd.
The eCoast technical memo highlights what is lacking in the port activities for protecting the area’s surfbreaks, and offers methodology to protect them.
We have also approached local iwi through the Mauao management committee regarding the placement of a monitoring system on the slopes of the Mount for the benefit of Matakana Island, such a system will assist with seeing how the dredging effects the ebb tidal delta and Matakana Island’s surfbreaks and the coastline that supports them, this would be beneficial for all parties.
Other major capital dredges took place in 1968 and 1992, and the challenge is to separate natural erosion and accretion effects on surfbreaks from manmade, there have also been three significant tsunamis over the last 150 years, which may have had an effect on the area.
The Bad news? We would have really preferred to see a proper monitoring system in place before Capital dredging started in order to establish good baseline data, that is obviously now not going to happen. SPS believes that while we cannot hope to influence the speed for iwi to consider the monitoring system for Matakana on the Mauao, SPS feel however that the Council and Port could move quicker to install a system for Mount beaches in the vicinity of Tay St.
The good news? Waikato University has an established partnership with Port Tauranga to monitor Port dredging activities/ impacts around the Mount, and while surfing science has not been a part of it to date, that is about to change, much of the data collected to date by the University will be useful for surfing effects analysis. Historical Google earth imagery and Whites aviation photography will also assist with creating an adaptive management model.