Hiking to the Meromictic Lake in Penang State Park
It was my English colleague-friend who told me about the meromictic lake in Penang State Park.
I can’t remember now why I contacted him in the first place. Or whether it’s because he replied to an old email or something when I was there. Anyhow, I was already in Penang for the street art when he told me. Apparently he discovered the lake hiking in the State Park.
So of course, I had to go too.
What is a meromictic lake?
A meromictic lake is a lake which has two layers of water that do not mix. Typically the bottom layer is more saline than the top (otherwise the top would be denser, and there will inevitably be mixing). This phenomenon results in a lake with a sharp halocline, or saline gradient, separating the two parts.
I suspected that the one in the State Park was probably going to be due to the lake being fed both by incoming sea tide, as well as a freshwater creek. But it surely needed to be fairly smooth, almost laminar flow for those streams not to disturb the stratification. Unless the lake was big, but it didn’t seem likely.
It’s pretty cool. I mean, it’s not like it’s visible to the naked eye, but nonetheless pretty cool.
Penang State Park
I took the Hop-On Hop-Off tourist bus to get to Penang State Park (Taman Negara Pulau Pinang, for locals). It was not a long ride, though it was nearly the last stop on the route.
The entrance had a convincing arch, assuring me of my arrival. Around the entrance were stalls and shops with sellers hawking food and other tourist wares. When I exited the park, this was where I bought my favourite blue-and-magenta pareo.
The hike to the meromictic lake
There are a number of jungle trails within the park. However, I had determined that the meromictic lake lay along the route towards Pantai Kerachut. So I registered myself at the ranger station and started on that route. Having just returned from the Blue Mountains, I had recovered a considerable amount of my hiking confidence.
The start of the trail was easy enough. It even had boarded tracks, and well-constructed steps to manage inclines, all of which looked reasonably well-maintained. I was pretty impressed, especially considering the not inconsiderable challenges posed by equatorial rainforest conditions.
A bit further though, and the park authorities have allowed more natural tracks to dominate. The atmosphere inside was – as is typical – very humid and very hot. The sun is blinding white, but the trees close overhead and buffer its intensity.
Occasionally there are some discreetly constructed hiking aids, such as anchored ropes to assist with inclines, or stumps over waterlogged stretches.
Later on though, there were quite a few tough stretches. It’s not exactly difficult, but challenging enough that I recalled how my friend claimed he hiked it in sandals. Which is impressive, considering the muddy inclines were slippy enough with my hiking boots.
The “invisible river”
Along the way the Forestry Department has placed information placards and boards, in an admirable persistence to ambush the hiking public with education.
I can never remember the information. Not even useful ones of survival importance, despite the best efforts of my mother and various quite excellent jungle guides. I kind of remember what the hanging root looks like that you can cut open for potable water, and the leaf that you can use as soap. But that’s about it.
But I recognise this one, because it is my day job. So I geeked out a bit to see it. :)
The usual term for ‘groundwater’ in Malay is a fairly literal translation, ‘air tanah’. But here, the powers that be have opted for a more romantic – albeit less accurate – term: ‘sungai halimunan’. Which renders it as ‘invisible river’. I sent the pic straightaway to a couple of colleagues, who felt it was rather a dashing improvement.
There are ranger guide services that you can ask for, but usually I can manage the smaller of our parks with a map of the trails. This is riskier for hikers who are not used to jungle trekking in general, since you would be less habituated to recognise what would be considered a trail – or ‘the’ trail.
Definitely have a guide for proper-sized jungles on the mainland, like Taman Negara or any of the Borneo ones, unless you have significant local woodcraft. Think of them as ‘mentors’ sharing trail knowledge if it makes you feel better. Quite enough people have been lost already. See, it’s not like the rangers make sure you check back out at the end of the day. So really, if you’re lost in there, there’s not going to be a search until someone else misses you.
In terms of fauna, I have found that at least for hiking in locations that are most accessible to visitors, you would be hard-pressed to see anything as long as you keep to the trail. Well, maybe skinks scurrying away into the detritus. And they’re so fast that I’d hardly count that as ‘seeing’, really.
But you can always, always hear the noisy jungle.
The Meromictic Lake
As I emerged out of the jungle into the open banks, and gained upon the lake, I immediately sensed my mistake.
Thus far during the hike, I had entertained fanciful ideas about what I could possibly engineer with just the things I brought on the hike, to detect the salinity change. Since I wouldn’t be able to visually appreciate the halocline.
An experiment, if you will. Just for fun. Nothing viable came to mind, but it was fun to pretend I might’ve thought of something. But it was beside the point with the too-shallow lake.
Timing is everything
It was a smallish lake. I walked around it and found the place where the sea pushed inland into it through a small channel. I didn’t yet have a tide app on my phone, nor did I check the tide tables beforehand. So I did not know the tide cycle.
Nonetheless, water was visibly flowing from the sea through the channel. It widened and meandered for a short distance to the lake. Apparently it was enough to quiet the flow enough, that by the time it entered the lake, it glided smoothly in.
The problem was the freshwater side.
On the other side, the creek had dwindled to but a trickle. I was there in the early part of the year, and the north of Malaysia does have a distinct dry season similar to Thailand.
There was not enough flow from the creek to balance out the flow from the sea. Even the water at the very surface was brackish to the taste. Perhaps later in the year, there would be a more equal flow meeting the tide. I can see how the stillness of the lake could easily cause the two salinities to settle as layers, undisturbed.
Pantai Kerachut & Epilogue
The trail ends at the little beach of Pantai Kerachut.
At one end of the beach, there was a turtle sanctuary of sorts. It seems that turtles do come to lay eggs on this beach. I learned it was possible to camp here, with permission from the park authorities.
It’s a charming strip of sand, shaded lightly by stands of casuarina trees. Reachable by boat as well as by hiking through the park, I could see families enjoying the beach and having picnics. In fact, I returned to the entrance by boat, with an off-duty ranger and his boatman friend.
This was, of course, the very boat trip with the Manchester medical students that led me to Barnsly, England, which took me on the second phase of my Blue Period odyssey.
*Tip: bring food and water in reuseable containers. There are no food sellers within the park, including at Kerachut beach, and limited sanitation services. So it is best to minimise the potential for litter. Think of the baby turtles!!