Letters: Rainwater management

This is a response to the article titled “NTB imposes environmental service fees”, (The Jakarta Post, Dec. 28) .

As a trained environmental engineer I see a big logical flaw. When rain falls on a watershed upstream of a reservoir, it can go to one of three places: into the ground as groundwater, evapotranspire (the process of vegetation evaporating water into the atmosphere) or flow off the watershed as surface drainage.

When a watershed is deforested, the trees will no longer evapotranspire water into the atmosphere.

Instead, the amount of surface drainage water is increased. The environmental damage which typically happens is erosion and downstream siltation of earth into the reservoir.

Rainwater is not retained by vegetation and the net result is increased flows of water into the reservoir. The only thing that can decrease the flow of water in a river is decrease in the rainfall.

Whoever is analyzing the problem of decreased flow of water into the reservoir has not conducted the proper research to find the cause of the problem and obviously is not properly educated and trained in the field of hydrology and watershed management. Why do I get the feeling this extra tax money will be going to some bureaucrats pocket and not producing more water?

Ben Johnson
Lombok, West Nusa Tenggara