Long before it was named Phnom Penh, some historians believe Cambodia’s capital was known as Chaktomuk, or “four faces,” because it lay at the four-way junction of the upper and lower Mekong, the Bassac and the Tonle Sap rivers.
The city’s founders were apparently well aware of the trade possibilities and strategic value of placing a city at the junction. The Royal Palace was built directly across from it. The name itself, historians say, shares interesting echoes with the famous four-way faces of the Bayon temple at Angkor Thom, with its enigmatic smiles surveying the kingdom in all directions.
At a seminar today at Hotel Le Royal, Mekong River Commission engineers will try to demonstrate that the junction is just as critical to the region’s environment now as it was when the city was founded.
They will release a study contending that more must be done at the junction to sustain fisheries and prevent erosion as far north as the Tonle Sap lake, and as far south as the Mekong Delta. The study reports that recent dredging and dike installation by the city will put only a small dent in the potential problems.
The study finds a particularly pressing problem at the entrance to the Bassac. A combination of natural and man-made forces have shifted the location of the entrance. That has caused rapid erosion on the eastern bank—up to 10 meters a year—threatening homes and livelihoods in the Koh Norea area, which has about 3,600 residents.
The shifting of the river’s direction has also created a rapid-current area known as a “scour hole” near the base of the Monivong Bridge. This could eventually threaten the foundation of the bridge, which already collapsed in 1964.
“If this one goes out, it could be economically disastrous for the country,” said Lieven Geerinck, navigation program manager for the commission.
Eventually, water flow to the Bassac could be restricted, Geerinck said. That could allow more saltwater to creep up the river from its mouth, destroying rice paddies near the shore in Vietnam. Even as Geerinck’s commission was studying how best to manage river flows by controlling development at the junction, Phnom Penh Governor Chea Sophara went ahead with plans to create a new park at the Chroy Changvar peninsula across from Sisowath Quay, which is eventually intended to host an exhibition hall.
Land is also being dredged so that the Royal Palace, which is no longer directly across from the junction because of sediment deposits that have lengthened the peninsula, is once again even with the junction, as it was in the 1920s, said Nicolas Mouy, a French engineer who is helping to supervise the development plans.
The plans also include filling in 20 hectares of land on the west side of the Bassac to make room for the planned $100 million Nexus Naga hotel complex, and creating a new dike on the Bassac’s west bank down to the Monivong Bridge. The plans, announced last December, are already mostly complete.
The commission made a quick study of the plans and found they led to a small positive impact for the area, especially in flood protection. But the plans would create a frequent, and expensive, need to dredge to preserve the channel to the Phnom Penh Port. Sand removed from the entrance to the Bassac will soon return, the study contends.
To stabilize the Bassac, Geerinck says, a new dike is needed on the east bank of the Bassac, at Koh Norea. The commission also proposes closing a small channel and reinforcing bank protection near the Monivong Bridge—all at an additional price tag of about $7 million, Geerinck said.
Mouy, the city consultant, said the commission’s recommendations seem reasonable, but he said the city could not be expected to fund them.
“The Mekong commission has different objectives [than the city]. They want to maintain the river. I think the MRC will have to fund it,” he said.
Geerinck said the seminar, which will be attended by engineers and officials from throughout the region, should create awareness of the importance of the junction.
“If you change something drastic here, the whole system could be disturbed,” he said.