Dengue Alert

Mystery of the widespread water stagnation at drains across Singapore solved?

To: Feedback Unit - MCYS

cc: Prime Minister Lee Hsien Loong
Minister for the Environment and Water Resources - Dr Yaacob Ibrahim

Further to my 21 Oct email below, attached please find photos taken today (24 Oct) at the flyover ramp entering the PIE from Adam Road coming from Farrer Road.

You will note that there is water stagnation at the drain there, possibly because of the lack of gradient to allow water flow. This is most puzzling because not only did the flyover engineers not make use of the "natural" gradient of ramp when constructing the drain (to allow drainage), they had chosen instead to "level" the drain (hence the "steps" that can be
seen from the photos), causing water stagnation - potential breeding grounds for mosquitoes. It is bad enough when drains constructed are not sloping, but to "level" a naturally sloping drain, I fail to understand the rationale behind such designs.

(By the way, I've noticed all these entry/exit ramps to/from expressways have similar "stepped-up" almost-level drains, so all potential mosquito breeding grounds).

As I've previously mentioned on numerous occasions (refer my 2 Aug 2005 posting - http://denguealert.blogspot.com/2005_08_01_denguealert_archive.html), in addition to the weekly cleaning of the drains (to remove water stagnation), why not do a thorough review to see the need to re-design all these drains that do not have sufficient gradient to allow water flow. This was a common observation in the many drains I've seen across the island (not just those at the flyover ramps mentioned above), the drains are almost level, hence water collected does not drain easily, resulting in water stagnation. That's why there are so many mosquito breeding spots in the drains across Singapore.

Isn't it better to fix the "source" of the problem, rather than the "symptoms"?

Jeff

posted by Dengue Alert In Singapore @ 10:49 AM