CityNews – “The Mae Kha Canal is as filthy as ever,” says Ricky Ward from the environmentalist group Gum Hak Doi Suthep.
An overburdened canal
The canal, which stretches through the centre of Chiang Mai, visible from the Night Bazaar, has been the focus of attention for Gum Hak Doi Suthep for several years.
Ward writes that the canal; shows, “BOD levels of 25 mg/l , with the Thai standard saying 5 mg/l and above is suitable only for navigation, and yet people do catch fish there.”
The higher the BOD levels mean the higher the amount of biodegradable matter in the water, which equates to how polluted the water is. The Mae Kha Canal, according to scientific standards, is well above the safe threshold for fishing or swimming in.
Ward adds, “In view of the total failure of authority to fix this problem NO FISHING signs need to be posted to protect children who live near the canal as well as adults.”
Ward explains that the weed cover at the canal also contributes to the lack of oxygen. “The last time this was removed was by mechanical dredging around 3 years,” he says, adding that this destroyed most of the trees along the pathway.
The dredging brought with other problems Ward says, explaining that at a forum organized late last year the Irrigation Department Engineer & Manager of the Mae Ngat Reservoir explained that the dredging which the municipality undertook had the effect of worsening the problem of low oxygen and hence the stench at the canal.
The question now, says Ward, is this:
“Can the municipality be persuaded to follow this advice and have removal by boat and hand instead?”