The Sepik River

After working for a week close to the coast around Wewak, we moved further inland.

With my colleague Sylvester, from the University of Technology in Lae, we set up a station in Maprik, an agricultural town in the foothills of the coastal ranges, on the edge of the Sepik plain. Important crops here are vanilla and cocoa, but the markets are not very good: a few years ago when the crops in Madagascar were failing, vanilla was bought here for 850 Kina per kilogram, and the town grew rich (one PNG Kina is currently about 40 Australian cents). Now it’s down below 5 Kina, and many plantations are being neglected.

I wanted to get to Ambunti, on the Sepik River, which has no road access. I had planned to get a small plane, operated by the Mission Aviation Fellowship, who support hundreds of small villages in PNG that have a grass airstrip and no other access apart from several days walk on a jungle track. But MAF were having their annual pilots’ meeting last week, so I left Sylvester in Maprik, and took a PMV truck down the dusty road to Pagwi, on the bank of the Sepik River. There I found a motor canoe going the 50 km upstream to Ambunti, and joined a few other people going the same way.

The motor canoe is a dugout canoe, made from a single tree trunk, like traditional river canoes here. But unlike those, which are double-ended, it has a transom at the stern where an outboard motor if mounted. It’s about 10 m long, about 1 m wide at the stern and tapering forwards, and the hull A 30 hp motor took 12 passengers and cargo upstream at 20 km/h, so the journey took about 2.5 hours, and I arrived at dusk in Ambunti.

The Sepik is the largest river in PNG. After it leaves the mountains, it winds slowly more than 1100 km to the sea. It’s what earth scientists call a ‘meandering river’. It is so ‘flat’ that gravity doesn’t pull it straight downhill. Instead it winds from side to side in large bends, which grow wider and wider until they are cut off, leaving the old channel as a ‘ox-bow’ lake on the plain beside the river. There are more than 1000 of these lakes alongside the river’s path.

There is very little development along the whole of the Sepik Rver. There is no mining or forestry activity and there are no major towns, so the river and the catchment are still in their natural condition.

After setting up my GPS equipment in Ambunti, I had time for a look around. At the top of the nearest hill, I visited a new telecommunications tower. It would be almost impossible to lay telephone cables through the jungle and swamp, so radio towers are the best solution. In a town with no road access and only a grass airstrip, fuel is expensive, so this transmitter is solar powered. My GPS gear uses one portable 35 watt panel to charge that batteries, so I was very impressed by 144 panels, each producing 75 watts!

At the end of my stay in Ambunti, MAF were flying again, and a single-engine Cessna 206 took me back to Wewak in 45 minutes, compared to the outward journey of about 5 hours in trucks and 2.5 hours in a canoe.

lukim yu,

dan

Comments

[Lab Lemming]

Hey Dan, sorry to ask about Antarctica while you're in PNG, but do you know if the ANU gang has enough data to constrain Enderby land rebound yet?

[Dan]

Back from PNG now! The good news from Enderby Land is that the equipment I installed last summer hibernated through the winter darkness, woke up as intended in the spring, and has been transmitting data back by satellite. We're really happy it's all working, but haven't been analysing the data as they arrive - we'll wait until the end of this summer and do it it one batch then. Contact me at ANU if you want more details!
dan