Thursday, January 14, 2010

Fish kill at Pais Ris: do you have a million bucks to spare?

Apparently, the recent fish kill at Pasir Ris (Dec 09) and Pulau Ubin (Jan 10) was not the only event concerning negative water quality in that area.

Other events include:
  1. 2008, 2009 - Pasir Ris Beach was found unsuitable for swimming because of the high bacateria (Enterococcus) count
  2. Dec 2006/ Jan 2007 - mass death of marine creatures in Chek Jawa due to drop in salinity caused by heavy rainfall
    (Update: a comment from "Death Note from Chek Jawa" recorded the salinity at 22ppt (parts per thousand). I believe this was  measured using a portable conductivity meter. I personally find measuring the salinity this way can be rather confusing to readers as the salinity is calculated by the meter based on the conductivity multiplied by a conversion factor. Unfortunately, this conversion factor can be quite different for different waters, ranging from 0.5 to 0.7. Hence, I personally find it more useful to report the salinity as the base measurement of electrical conductivity adjusted to 25oC.)
According to AVA, a monitoring programme has already been in place to test the water quality in the said area. Without elaboration from AVA about its programme, I shall not comment on its effectiveness but here are my suggestions for AVA/NEA for a price tag of (you got it!) a million bucks.

Since this Pasir Ris/ Pulau Ubin/ Changi is such a problematic area in terms of water quality, install a continuous monitoring system with maybe 3 to 5 monitoring stations to provide real time data for immediate response. The technology is there... you just need money. Even manpower is saved since staff only go down to the field for further investigation or to do sampling for a more detailed analysis.
  1. 3 - 5 buoys containing water quality and metereological sensors, telemetry package, solar panels and batteries. See previous post. They should be strategically placed for maximum monitoring effectiveness - 1 at north of Pulau Tekong, 1 south of P. Tekong, 1 between P. Tekong and P. Ubin, 1 north of P. Punggol and 1 north of Pasir Ris Beach
  2. One/two water quality sensor packages installed on each buoy. See previous post. They should be able to measure depth, dissolved oxygen (DO), turbidity, electrical conductivity (EC), temperature, pH, chlorophyll, nitrate, ammonia. I was told that each package can cost about S$15000.
  3. Remote server (perhaps in the agency's HQ) with the capability to receive data via cellular signals from the buoys/sensors.
  4. To handle these vast amount of water quality data, GIS (geographic information system) should be installed on a workstation linked to the remote server to document and analyse the data. See previous post. A GIS can also provide a visual display of the water quality with colour coding. Any unusual or out-of-spec event should trigger an alarm. 
  5. Better still, install a modelling software to tie in with the GIS. Some free models can be found at USEPA. A properly calibrated model can make predictions and simulations on the water quality in the area to prepare for future events of similar or worse magnitude.
  6. Qualified and trained manpower to use and maintain all the above goodies.
All the above may not even amount to $1M. I am sure this system will reduce the guesswork involved in future events e.g. whose fault? and probably allow for rapid remediation if required.


supernovette said...

Hi I was wondering what you think about most recent fish kills happening on the NE coast (e.g. Do you suspect any industrial dumping or simply hot weather causing low DO? I'm so sad about the poor fish and farmers who just lose 80% of their capital and also angry that NEA/ AVA are so untransparent/ even bochap about fish kills.

CK said...

Hi, without testing the water quality for certain parameters, it is hard to tell for sure.

I do not know of anyone doing a comprehensive water quality test AND publishing the results in response to fish kills over the years in the Pasir Ris area.

I will go down one of these days to do a basic water quality test there in collaboration with Channel News Asia. I am not sure whether it will show anything in the water because of the time lag but at least it can give an idea of the water quality now.

supernovette said...

Wonderful. Hope improves transparency. Though of course more needs to be done on tracing waste upstream. Any chance you will post findings on this blog?

CK said...

Yes, I will post the results of the water quality test once they are ready.