Mount Maunganui

Construction, led by local contractors, started in 2005 and ended in 2008. Poor weather, cost overruns and other problems plauged construction. According to ASR, the construction team never completely built the reef to match the design specifications.

Construction started on the “left” side of the reef in November 2005, and after a break due to a windy summer, continued in early March 2006 with the addition of three bags. Even with the reef only partially complete, on March 8th 2006, Mount Reef turned a small windswell into quick, head-high, left-hand barrels.

In October 2006, the side of the reef that produced right-hand waves was completed nearly to specifications. Mead and Borrero report that the waves breaking around this time were considered very good and offered barrels, as designed. Unfortunately, one of the geotextile containers was damaged during installation and had to be removed. Because of the gap, which was left unfilled for 9 months, an adjacent bag slumped and lost roughly 1m in height.

The gap was filled and the construction continued as funding and weather would allow until June 2008. The resulting structure was far from the specified design and fell critically short on volume at 2,800m³ vs 6,000m³ as designed. Total cost of the project was around $1.5 million NZ (just under $1 million USD).

The Results

Reports on the performance of the Mount Maunganui artificial surfing reef vary wildly. Research and press articles indicate that Mount Reef occasionally produced some really good surf during and after installation, but became increasingly fickle as time passed. According to most reports, the poor performance was primarily due to construction issues and failure to build the reef to the specified design.

When it worked, Mount Reef tended to produced quick barreling waves similar to what you might find at a ledge like the Box but smaller. The ride length was between 20 and 40 meters left and right.

Mike Smith, who had Mount Reef to himself on a particularly good morning in October 2006, told the NZHerald “I was definitely pleased with how it was working. Pretty awesome for the Mount.”

Good days like that occurred with decreasing frequency through 2009.

In December 2009, Surfer.com reported on a fun session at Mount Reef. A clean 1 meter swell produced head high waves that offered some deep barrels with a quick, sharp drop that was dominated by body boarders while it humbled most surfers.

The Mount Reef also provided research opportunities into the reef’s effect on other coast processes including beach profiling, ecological and safety surveys. In a 2009 study, Weppe’s research suggested that the beach widened up to 25 meters along roughly 150m of beach to the southeast of the reef. However he concluded that shoreline was dynamic, and that there was no evidence of a persistent salient. The reef also produced more sandbars around the area which helped reduce closeouts, according to some reports. From an ecological standpoint, the biodiversity on the reef was found to be similar to adjacent rocky reefs.

After 2009, performance deteriorated quickly. Sand leaked from some bags while others were buried in sand. Scouring lead to unexpected holes in adjacent sand and rip currents lead to increased lifeguard saving activity.

In the December 2013 report titled “Mount Maunganui Reef – Assessment of Management Options”, Dahm and Gibberd conclude that “the expected positive impacts on surfing amenity and beach width have largely not been realised…. partly due to problems with construction.” The report also pointed out a significant and unanticipated scour hole on the leeward side of the reef. The hole was three times as big as the reef itself and 1.75m deeper than the ambient sea levels (Scarfe, 2008).

Dahm and Gibberd also point out safety concerns in their report, including stronger and more frequent rip currents. Through interviews with local lifesaving clubs, they found that “the reef has increased the hazard posed to swimmers …and that the reef should be removed.” Additionally, in 2011, local lifeguards labeled the reef a “dangerous flop” according to the Otago Daily Times and recommended its removal. The lifeguards said the reef was causing an increase in rip currents.

The Dahm and Gibberd report also found “very clear evidence of damage to bags near the apex of the structure”. This can be seen seen in the image below, where deeper blue spots can be seen in the apex of the reef. The image also shows (or fails to show) the buried smaller bags on the outside of each arm.

According to Shaw Mead, who also previously worked for ASR, the Mount Maunganui artificial surfing reef was “over-sold and under-delivered”. In a 2011 report, Mead reported that the reef delivered quality waves when it was initially installed but deteriorated since then. Between April and September 2008, Mead recorded surfing activity on and around the reef. Out of 102 days sampled, surfers were on the reef 10 days. They were on the beach adjacent to the reef 28 days. Mead cites the missing bag from 2007, settling and leakage and a lack of volume (2800m³ installed vs 6500m³ designed) as the primary problems.

The Bay of Plenty Regional Council agreed that the reef was dangerous, and not worth saving. They decided to remove the reef at a cost of $87,000 NZ. Construction crews completed the removal in November of 2014.

Sources: Surfline, Adventure Sports Network, NZ Herald, Otago Daily Times, Surfer, Mount Maunganui Reef – Assessment of Management Options (Dahm and Gibberd), Marine and Coastal Resource Management: Principles and Practice (Mead and Borrero), The Reef Journal.