Probocis versus Human

One of the difficulties working at the Ministry of Development is that we are constantly faced with issues of trying to meet the expectations of everyone. Interestingly enough we looked after infrastructure and physical development but at the same time we are also responsible for the environmental issues.

Lately, a growing concern voiced on the internet over a project at Damuan River. A number of photographs have been placed and I have enough tags to make me more than aware of what the problem was. Apparently an area which has been used as a sanctuary for Proboscis monkeys is no longer available for the monkeys because of development works.

First of all, the development work was to deepen and widen the Damuan River because if this was not done, there will be floods to the houses further up the river especially around the Mulaut areas. Secondly, the consultants did take into account the proboscis monkeys. There are two sites for the proboscis monkeys, one is where the site has been cleared and the other is across the river on a much bigger area and more secure as it is an island. So the proboscis monkeys in the affected area can swim to the other side.


Email from project manager:

IEC Sdn Bhd was instructed by Dept of Drainage to undertake channel widening works at Madewa with due regard to the sensitive environs of Makam Luba and the proboscis monkey habitat.

To alleviate flooding in residential areas upstream in Ban Mulaut a channel of 50 metres bed width is required. The existing channel varies 20-30 m width.

In order to reduce loss of riverside vegetation and habitat, we are diverting the outlet channel to the west of Pulau Luba (around the Bengkurong end of the island), thereby negating the need to clear along the length of Pulau Luba and Pulau Ranggu. Hopefully this channel will also restrict access of feral dogs and create more of a sanctuary for the monkeys on the islands(although they regularly swim channels).
The channel diversion does require clearance on the Kg Bengkurong side where monkeys have been sighted, however we consider the untouched habitat on the islands is of sufficient size for temporary displacement. Riverine vegetation will be replanted once works are completed.

I have attached the environmental mitigation measures adopted for the project for your information and hope this addresses your concerns.




Sg. Damuan channel at Kg. Bunut Perpindahan is being widened to enable the conveyance of floodwaters into Sg. Brunei thereby reducing flood damage problems in Ban Mulaut, Kilanas and Bengkurong.

The location is a high quality environment: it is scenically attractive and of archaelogical significance (Makam Luba is a historic burial site for Brunei Royal lineage). It is also a foraging site for Proboscis monkeys which graze at the riverbank of Pulau Luba and are an attraction for visitors and tourists.

“Proboscis monkey groups range in size from 3 to 30 individuals, usually based on one male and a number of females. They occupy a home range of less than 1 sq. mile (2 sq. km), and sleep alone in trees reasonably close to other troop members. Mating is undertaken anytime of year, with a single young born after a gestation of 166 days” (

Environmental measures are incorporated into the Design and Works Plan to reduce the removal of mangrove and avoid long term disturbance to the proboscis monkey habitat. Measures include:-


• Diversion of the new flood channel to a silted up reach of river at the upstream end of Pulau Luba, thereby avoiding any disturbance to the riverbanks around Mukim Luba where the proboscis is regularly seen.

• Restricted clearance of vegetation on riverbanks to the urbanized sides of the river only (away from the island habitat).

• Widening of the channel at the northern end of the island will reduce access for feral dogs from urban areas improving the sanctuary character of the island.

• The area of Pulau Luba and adjoining Pulau Ranggu is approximately 2.5 square kilometre, providing adequate displacement area for the monkeys should they wish to move. Proboscis monkeys regularly swim river channels and could cross Sg. Brunei to mangroves at Kg. Kilugus if desired.

• Replanting of mangrove trees and nipah on the reformed southern riverbank, for rehabilitation of natural habitat.

Works Program

• Excavated material treatment will occur to the South of the river, 0.5 – 1.0km away from the island habitat.

• Channel work will be undertaken using floating dredge returning all excavated material to vacant land away from Pulau Luba. This minimizes heavy machinery working close to the proboscis habitat.

• Overall Works Program is 15 months. However, channel works at northern end of Pulau Luba will take 15 weeks to complete, thereby minimizing the period of equipment working in proximity to Pulau Luba.

• No concurrent works will be undertaken on or around Pulau Luba, allowing temporary displacement of the monkeys whilst channel works are ongoing in Sg. Damuan.

• Excavation work will be supervised by Department of Drainage and consultants to ensure environmental mitigation measures are implemented fully by the contractor throughout the Contract Period.


We can't please everyone but we have tried as best as we can.


Popeye said…
This is very upsetting. I can only hold out hope that the company makes good on its promise to replant the nipah and mangrove vegetation.

Proboscis Monkeys are a regular sight near Damuan and Luba (and hopefully will continue to be once the project is under wraps), but they can also be found on Pulau Chermin, at the other end of the Brunei Bay. Tour companies, please take note.
Anonymous said…
Dear Mr BR, thank you for your explanation. We live at Kg Bunut Perpindahan, the Sungai Damuan is right in our backyard..we can see the project from our kitchen window. We used to be able to see the proboscis monkeys 'hanging out' at the nipah and mangrove vegetation..but not anymore.

While we can be assured that the well being of the proboscis monkeys are being highlighted and being considered, I couldnt help but wonder, would there be any impact on the riverbank as a result of the project?

I am very concerned about this, if there's any soil erosion at the riverbank caused by the drainage works...if it will affect the residences along the Damuan river? Has the consultant also considered the well-being,long term safety of the residents along the Damuan river?

Please would be very much appreciated. Many thanks
Apologies for the delay in answering. I referred your query to the consultant in charge of the project. Here is his answer:

The project is not expected to generate erosion along the existing banks of Sg Damuan at Bunut Perpindahan. Widening of the channel will result in slightly lower velocities of floodwaters and floods of shorter duration, thereby reducing potential for soil erosion. Retention of mangrove trees on the bank closest to Bunut Perpindahan also assists with erosion protection. And if you notice upstream above the Jalan Bengkurong bridge the channel embankments are quite stable following widening there several years ago. Any changes to the existing banks will be monitored through the construction and maintenance period. For the long term we expect floodwaters to flow through this new channel to the west of Pulau Luba and away from houses at Madewa.

Hope that helps
Anonymous said…
I just wish there was more synergy between relevant departments and less 'siok sendiri'. Its sad this issue baru ketahuan whereas in reality we've known about the plight of the proboscis monkeys for more than 4 years. I hope the current interest in their plight is sustainable before we move on (typical in Brunei) to the next big thing. I truly wonder if we Bruneians realise we are destroying potential opportunities - people identify Oz with Koala and Kangaroo, why can't Brunei have the proboscis as tourism icons. Too bad we're slowly killing the monkeys that lays the golden egg... I still believe development and conservation can co-exist in the same time-frame! The question is where is the enforcement and will!

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