The North Narrabeen master plan: What's at stake?

Stu Nettle picture
Stu Nettle (stunet)
Surfpolitik

What makes a great wave great? Besides good swell that is. What is it that happens under the surface, down there among the bottom contours that can transform a line of swell into something surfers will devote their whole lives to?

At reefs and rock breaks, where the bottom is somewhat permanent, the answers are evident; bottom topography can be mapped and the secrets of a surf break exposed. Yet at sand bottom waves, where the system is in a constant state of flux, the secrets are less tangible and therefore harder to know.

Last year the entrance to Narrabeen Lagoon, which flows out in front of the famous North Narrabeen left, was blocked and a joint council project initiated to clear the channel. The project began in September 2011 and was finished early 2012. Interestingly, while the project was underway the waves at North Narrabeen were the worst they'd been in many years. It became apparent that Narrabeen - the most famous wave in Sydney, and the home of Australia's most successful and fiercest boardriders club - was dependent on continuous sand flow. It was one of the secrets to its wave quality.

The dredging project at Narrabeen Lagoon finished in February and the channel now flows freely again, yet local surfers have found that the wave quality hasn't been fully restored. They, along with local environmentalists, are now pointing the finger at the sand dune at the very tip of the Narrabeen Peninsula. The dune - known as Birdwood Dune as it sits at the northern end of Birdwood Park - is adjacent to the lagoon entrance and directly in front of Northy.

Upon being told of this news my first response was to dismiss the local reaction as misguided. So the waves aren't as great as they were, what role did a vegetated sand dune, seemingly in its natural state, have to do with it? Were the locals guilty of sporting rose tinted glasses and looking to apportion blame?

According to Brendan Donohoe, local surfer and Surfrider representative, Birdwood Dune has a lot to do with the current state of the waves at Narrabeen. The whole area has been mismanaged, and to explain how Donohoe gives me a short history lesson on the region.

Although the Birdwood Dune looks to me like a healthy, natural sand dune I'm surprised to learn it is an artificial construction. Birdwood Dune is actually man-made. The dune was built in 1974 and 1975 following a period of intense swell activity. It was during this time, when Sydney was ravaged by huge storms, that the dune was built as a buffer to protect the coast and the lagoon entrance. Vegetation was planted to stabilise it and access restricted to set paths.

Once it was built Birdwood Dune did its intended job of sand gathering well - too well, in fact. Originally designed at three metres above sea level the effect of a constant sand supply from both the lagoon and longshore drift combined with surface vegetation that trapped the sand meant its size grew far beyond the original design. Indeed, sand that would naturally find it's way out to sea, forming the banks under Alley Rights, Narrabeen proper and Carpark Rights, now gets trapped in the ever-growing Birdwood Dune. Such is the height the dune has reached that it now blocks the line of sight between North Narrabeen Surf Club and the waves. A sure sign of its ever-growing bulk and how it is impeding natural sand flow.

A commonly cited fact about Collaroy - Narrabeen is that it ranks as the beach third most at risk from coastal processes in Australia, though a source for this information isn't easy to find. Perhaps it's one of those factoids that gets forever repeated without anyone stopping to confirm it. What can be confirmed is that the Collaroy-Narrabeen stretch is an extremely dynamic coastal system with many smaller interdependent systems within it. If one component is tampered with the effect is felt throughout the whole system.

What can also be confirmed is that the Collaroy-Narrabeen stretch, including the beach and the lagoon, is one of the most intensely capitalised shorelines in Australia with Warringah Council estimating the real estate to be worth in excess of $500 million. The council have good reason to want to protect its coastal properties. What is being questioned by the likes of Brendan Donohoe, Tom Kirsop and others are the methods used to achieve this.

Recently Surfrider Foundation listed North Narrabeen as an endangered wave due to the sand-starving impact Birdwood Dune is having on the waves. Not a title given lightly, Northy is now keeping dubious company with Bastion Point in Victoria, Kirra in Queensland, and Tam O'Shanter in Tasmania.

It's with this background knowledge that Warringah Council has proposed a master plan to improve public amenity at North Narrabeen, including Birdwood Park and Birdwood Dune. "The development of a master plan is to create an overall vision for the area to stop ad hoc development and to ensure the area is conserved and maintained," said Warringah Mayor, Michael Regan last December. In the same statement Mayor Regan also said, "North Narrabeen is a National Surfing Reserve with iconic surf breaks and a rich surfing history." A statement aimed squarely at Narrabeen's large surfing constituency.

In May a draft version of the master plan was released by landscape architects Clouston Associates. To the dismay of local surfers it does nothing to address the state of the 'iconic surf breaks' of Narrabeen. To the contrary, this version further increases the sand trapping capability of Birdwood Dune. On the western side will be a new asphalt carpark, on the eastern side a new managed dune area replanted with Acacia, and on top of the dune a permanent boardwalk leading from the surf club carpark to the northern tip of the dune.

It's obvious what Warringah Council is trying to achieve at Narrabeen. Rather than overseeing an ever-changing coastline, and dealing with the ongoing costs and risks to property that may occur, they can simply erect unimposing yet permanent structures on the dune. Reclaim it as an area for recreation and lock it down for good.

The issue, however, is that sand bottomed waves such as North Narrabeen rely on the surrounding ecosystems to be in a constant state of flux. Sand needs to be available for storage and nourishment as the perpetual cycle of storms and swells change the profile of the beach and the underlying shape of the banks. What is becoming apparent to Narrabeen surfers is that the state of the Birdwood Dune is being reflected in the local bottom topography. An abundance of sand on shore heralds a shortage of sand underwater. It's a situation they don't want to become permanent.

Comments

memlasurf's picture
memlasurf's picture
memlasurf Wednesday, 4 Jul 2012 at 4:50pm

I am a landscape architect and surfer and last time I looked Cloustons didn't have any real keen surfers on their payroll. Understanding the ever shifting processes at work is the first step in the design processes. I would like to see Cloustons analysis plans to check if they even took the coastal processes into consideration (or if they were even allowed to in their fee). There was a project here in Victoria at Frankston where the landscape architects were obviously from Latte Land RMIT and knew nothing of the wind, tides, long shore drift, etc.. and consequently was full on ongoing issues like sand drift. If the Warringah council are serious about the role the wave quality plays in the area, they need hydrodynamic studies, historical studies, etc. built into the analysis before trotting out pretty plans.

andycumo's picture
andycumo's picture
andycumo Wednesday, 4 Jul 2012 at 5:02pm

It should also be noted that this dune has been detrimental to the entire ecosystem of Narrabeen Lakes.
The reduced flow to the ocean has caused large amounts of sediment to back up in the lagoon, which buries sea-grasses that are essential for fish breeding nurseries.
The reduced depth in Narrabeen Lakes, due to the backing up of sediment has also caused warming of lake which is far too warm for many fish species.

So it shouldn't just be surfers jumping up and down about this dune! We need to get everyone on board!

memlasurf's picture
memlasurf's picture
memlasurf Wednesday, 4 Jul 2012 at 5:54pm

For sure it sounds like there are a few more issues than parking and pedestrian access.

peter73's picture
peter73's picture
peter73 Wednesday, 4 Jul 2012 at 8:22pm

Fortunately this initial concept for development has been made public at an early stage, meaning that the local surfers, fishermen and residents are aware of the potential outcome if action isn't taken.

grommit's picture
grommit's picture
grommit Wednesday, 4 Jul 2012 at 10:50pm

With all the $$$$ on the northern beaches & the amount of people jostling for a decent wave, it deems like the times come for artifical reefs to make an appearance on the Narra stretch. Blow Northy it's overated anyway, this will sort the ongoing erosion problems for all the cash chukkers living on the beach give surfers a decent wave to have a crak at in most conditions & restore & retain the pride all the Narra locals have , not to mention surf comps etc. C'mon Warringah Council have a go.

fitzroy-21's picture
fitzroy-21's picture
fitzroy-21 Thursday, 5 Jul 2012 at 12:12pm

I,ve carried on enough about this in other posts, but in the 3rd photo (airial shot), when I was growing up it was deep water all the way to the caravan park bridge and from there wide and reasonably deep to the, now, entrance. I've watched it progressively choke until I moved years ago. Now look at it.
Being a lagoon, the old entrance used to shift anywhere across that whole birdwood dune area. Now, because they forced it over to the rock pool, it can't get depth to maintain maximum flow because of the coffee rock under it.

fatjackdave's picture
fatjackdave's picture
fatjackdave Thursday, 5 Jul 2012 at 1:05pm

There's a fair bit of half info in this article. Creating some strong, positive comments, but mostly slighly off context. The masterplan was initiated due to disappearing sight lines from the water to the life saving building. Nearly all of the structures currently exist - including the mentioned carpark. MHL have modelled the impacts.

Most importantly, Birdwood dune is a tiny part of the problem. The bridge near the caravan park is the source of the restricted outflow and is the reason why the lagoon is more tidal dominated than flood.

fatjackdave's picture
fatjackdave's picture
fatjackdave Thursday, 5 Jul 2012 at 1:24pm

Continuing on...an image reference as an example - check #17 here to see the site prior to the bridge. A smaller version of Birdwood lagoon exists at this point in time.
http://acms.sl.nsw.gov.au/album/albumView.aspx?acmsID=73267&itemID=823330

After the rain of the current months, it would possibly wash away, but natural drift would return it before long.

malibumick's picture
malibumick's picture
malibumick Friday, 6 Jul 2012 at 11:48am

Thanks for the link fatjackdave. As a kid in the 1950s I remember the lake entrance as wide as #17 and in times of flood we'd pinch rowboats and float down the rapids. No shortage of sand flowing out and a great wave out in the alley.
Note in the old photos how wide the beach is all the way to Collaroy. At the end of Loftus St(4-5 blocks south of northy) there was a sand quarry with a big scoop on cables and truck after truck of beach sand was carted away for building. All the sand hills have been carted away and now it's all housing with back fences constantly under threat from erosion. Used to be big channels all along the beach with lefts & rights aplenty.The lake was clear as could be with big fish aplenty.
Open the entrance up I say and take it back to how it was before the white fella started stuffing around with it!

the_b's picture
the_b's picture
the_b Friday, 6 Jul 2012 at 4:05pm

I'm lucky to have access to aerial photography dated 1943 which shows the whole lower section of the lake choked with sand. The sand delta from sediment coming in the lake (which now currently extends to just upstream of the caravan park) actually located all the way past Pittwater Road bridge back then, with the visible edge of the sand delta extending from west of Wimbledon Ave (north end ) to Robertson Street (East end) with Wimbledon Island comprising a part of the delta.

The mouth area east of Ocean Street is completely blocked off and it's 100m between the lake and the surf. No veg on Birdwood Dune, and no one in the water ; ) Ocean Street bridge was built by 1943 in pretty much it's current configuration.

Anyway just an observation... very interesting to see how the lake has changed over the last century.