Friday, January 29, 2010

Singapore Bug List

In response to queries from some readers regarding the types of bugs (macroinvertebrates) found in Singapore's fresh waters, I have compiled a quick list of the bugs I have encountered.

I have broadly classified our fresh water bodies into 3 types:

1. Ponds
Figure: A very stagnant pond next to Sungei Ulu Pandan

Figure: Turbid pond in the forest near Dover MRT station. (Sorry folks, if you intend to visit this one, forget it as the whole area is now under construction.)

Bugs present:
  1. Leeches! And big ones too! These are whoppers compared to the tiny terrestrial ones commonly encountered in Malaysian jungles. I was told that they are Buffalo Leeches (unverified).

    There are also tiny ones (fingernail sized).
  2. Dragonfly
  3. Damselfly
  4. Water stick insect
  5. Mayfly
  6. Pond skater
  7. Chironomid ("Bloodworm")
  8. Sludge worm
  9. Beetle
NO Caddisfly!

Unsurprisingly, when the dissolved oxygen (DO) level drops low (say below 2-3mg/L), the ponds become infested with leeches which crowd out the friendly bugs e.g. Mayflies.

2. Streams

Figure: Ngee Ann Stream riffles surrounded by secondary forest then. If you want to visit this wonderful stream, do it soon because the adjacent land is cleared and under construction (yawn, what else is new?). Who knows when the stream will be paved over to make way for yet another condominium?

Figure: Binjai Stream. A good old clear stream PROVIDED rains do not wash sediments into it.

Figure: Tributary into Sungei Pandan. This is a good example of a canal that looks like a natural stream.

Bugs present:
  1. Snail (lots of them in the tributary leading to Sg Pandan)
  2. Collembola
  3. Dragonfly
  4. Damselfly
  5. Eel
  6. Shrimp
  7. Crab (Binjai Stream. Yes, this stream is clean and natural enough to find crabs.)
NO Mayfly! NO Caddisfly!

3. Freshwater reservoir

Figure: MacRitchie Reservoir. Fully exposed to the sky.
Bugs present:

  1. Mayfly

  2. Dragonfly

  3. Damselfly

  4. Chironomid

  5. Shrimp

  6. Snail

  7. Lentil Shrimp

  8. Caddisfly
NO Leech!

Disclaimer: Haha, this is definitely not a complete list. All the above bugs are based on my experience in those waters.

Strangely, NO Plecoptera (Stonefly) and Megaloptera have been found so far in Singapore waters! These 2 orderse are supposed to be really common in other countries e.g. USA, UK.

Acknowledgement: Many thanks to Esther for introducing me to the world of water bugs! I am still learning lots more from her.

One last comment:
Forget about finding bugs in artificial fish ponds with little or no natural substrate - e.g. below

Thursday, January 28, 2010

Courses on water quality

In response to queries about my courses on water quality, I have listed them here for easy reference.

  1. AEM (advanced elective module): Water Quality and Pollution
    This 40-hour module is essentially for upper secondary school students as dictated by MOE (unless the school is willing to forgo the MOE subsidy).

    Check out this post for more details.
  2. My forest is DYING and the role of water quality
    This 1-day course is mainly catered for MOE teachers even though MOE HQ staff have attended it. I was initially told that the course title sounded wacky and school management (the approvers for my customers - teachers) would not be amused with such a title. However, many participants found the title catchy and wanted to learn more about the course. Hence, the title stays as it is.

    Check out the course details here.
  3. Water Quality in Natural Habitats
    Another 1-day course. This is more suitable for secondary school students and above as it involves laboratory work in addition to the standard (at least for me) field work plus classroom lesson.

    Check out the flyer here.
  4. Freshwater quality and biodiversity
    Duration of 1 day too. This course is suitable for primary school students and above. There is no laboratory work. Instead, the participants get to see aquatic bugs (macroinvertebrates) up close and personal - an  unforgettable experience to most since people in Singapore hardly go out to "play" with nature anymore.

    Check out the flyer here.

FAQs on AEMs (advanced elective modules): Water Quality and Pollution

  1. What are AEMs?
    Check out characteristics of AEMs
  2. What are the dates and times?
    The teacher in-charge will have to work out the schedule with coordinator of the AEM (typically a Polytechnic lecturer). Each module is 40h so it will take about 5-6 full days either condensed into a week or spread across several weeks.
  3. How many participants are required?
    Minimum 20. I normally stick to a maximum of 20 for safety reasons, especially in laboratory and field work.
  4. When must I give you the list of participants?
    The name list can be sent to me latest 1 week before the course starts.
  5. What is the cost?
    br>$400 per pax. MOE can subsidise $345 with $55 coming from the student or school.
  6. How do we go about applying for the MOE subsidy?Check out application of funds for running AEMs
  7. Are teacher required to be present?The presence of a teacher is preferred, especially for the field trips.
  8. What is the AEM, Water Quality and Pollution about?Check out my flyer or the description
  9. If I need more information, who can I approach?For further clarifications on policy and implementation issues, please contact:

Water Competitions for Students in Singapore

I have regularly been asked by school teachers whether Singapore has any competition based on a water theme for their students. That's right, participating (and winning) in competitions are pretty much part of the job scope of our teachers nowadays, from primary right up to tertiary level. Who knows, next time, even our kindergartens are not spared.

These are the few I can think of.
  1. Singapore Junior Water Prize (by Ngee Ann Polytechnic and Lien Foundation)
    This project based competition is as close to a water theme as you can get. Registration for 2010 closes on 26 Feb 2010 so hurry! Winners of this Prize will get to compete internationally in the Stockholm Junior Water Prize.
  2. Singapore International Water Festival (SIWF) @ the Barrage (by Singapore Polytechnic and PUB)
    This is NOT a project based competition. Instead, it hosts a range of competitions - Environmental Quiz (a, b), Amazing Race, Walking on Water, Solar Boat Race, International Raft Race. The Festival is scheduled for Jun 2010 though the details have yet to be put up.
  3. Green Wave Environmental Care Competition (by Sembawang Shipyard)
    Project based. Submission of proposal form closes on 31 Mar 2010. This competition covers more than water as it stretches over many aspects of the environment. Entries need not even be technical since social and educational projects can be accepted.
  4. Singapore Science and Engineering Fair (SSSEF) (by Singapore Science Centre, MOE, A*star)

    Project based. It covers a diversity of topics in science, maths and engineering. Winners will represent Singapore to compete at the Intel ISEF (International Science and Engineering Fair).
  5. Weather Station Project Challenge (by Senoko Power Station)
    Project based. Related to geography, specifically weather. I am not sure whether this is a yearly competition. There seems to be little information about it.
  6. Singapore Land Authority (SLA) Spatial Challenge
    This competition involves the use of GIS (geographic information system). The project obviously has a slant towards geography. The good news is the participants will get to be trained in GIS (a very useful tool - see my earlier post) for free.
  7. Clean Water Challenge (by Singapore Polytechnic School of ABE)
    This competition involves the participants building a water filter with given materials on the spot. The winning filter produces the cleanest effluent in the shortest time.
  8. Other inter-school science competitions at cluster or national level (by MOE)

Friday, January 22, 2010

Water lessons from Haiti

Facing a cascade of news about the situation in Haiti after a magnitude 7 earthquake, I can't help but compare Haiti with Singapore. (I know this sounds off topic but don't worry, I will get to the water part soon.)

First, a summary of the aftermath in Haiti:
  1. 100000 - 200000 people died (the number varies, depending on the news source)
  2. Survivors are in dire straits - severe lack of food, water and shelter.
  3. The various institutions (government, law enforcement, health care etc.) are seriously crippled.
  4. Looting is rampant in the capital.
Some recent news of Haiti:
HAITI: Agencies rush to get water to earthquake disaster zone (19/01/10)
Haiti's Environment Needs Long-Term Help: Experts

Most of us would immediately sympathise with the Haitians. But if asked whether the same thing can happen in Singapore, most of us will instinctively shake off such a possibility.

Here is an informative post discussing the possbility of an earthquake here. Naturally, there is no definite answer since earthquake prediction is not an exact science though our odds of not having an earthquake seem pretty good.

However, I remember reading a book in my childhood about an earthquake recorded in Singapore in Feb 1861. The interesting part is not the earthquake but the rain of frogs and fishes that preceded the earthquake. See:
  1. It's raining frogs and fish
  2. Frogs rain
  3. Weird, weird rain
However, there was no mention of casulties, magnitude of quake or damage level. I presume that was linked to the quake in Sumatra at that time.

My point is: Singapore's history is so short that we won't know if there ever was a killer quake in the past while we assume we are safe.

Anyway, it does not take an earthquake to disrupt civilised society. You can choose from any of the following crises (some more probable than others):
  1. Terrorist attack
  2. Tsunami
  3. Nuclear power plant accident
    1. Indonesia - a, b (is Indonesia still building its nuclear plant in Java?)
    2. Malaysia
    3. Singapore
  4. Social unrest
  5. Economic collapse
  6. Pandemic (H1N1, H5N1, Sars etc.)
  7. 20 December 2012 (this will be hard to survive)
Back to water...

It is said that you can only live 3 days without water yet how many of us actually pause to ponder about how the water reaches our taps and where to get water if our taps run dry? From Haiti's experience, water is clearly a top priority commodity once the normal channels of water supply are disrupted. Yes, I am sure people will kill to obtain this precious fluid.

Check out the following sites on handling a crisis/ emergency in Singapore.
Singapore Government Crisis News Website
Water distribution (under purview of SCDF)
Stockpiling of essential household items (SCDF)

We are encouraged to stockpile food, candles, first aid items, torches, radios but water is glaringly missing from the list. (Do not be mistaken. The above items are critical too.) Instead, in an emergency, water is to be collected at distribution points served presumably by water tankers. How reliable is this? If 10% of the population is incapacitated, will the water tankers still run? What about 50% of the population being incapacitated?

It is my belief that each family should stockpile some water. How much? This is trickier to answer. A good estimate is to have 8 litres per person per day to survive comfortably. Depending on the severity of the crisis, you may need to store enough water for 3 days to 3 years but I feel 3 days should be the bare minimum. (Updated by author on 6/4/17: I smiled inwardly to myself when I reread this estimate of 8L per person per day because I was reinforced with the Sphere standards in the Sphere Handbook the past few weeks. For those unfamiliar with Sphere, "The Sphere Handbook is one of the most widely known and internationally recognized sets of common principles and universal minimum standards for the delivery of quality humanitarian response." Anyway, it suggested a minimum requirement of 15L/day/pax! Remember, this figure applies to refugees from manmade and natural disasters. But bear in mind that it includes washing, bathing (the minimalistic kind), cooking in addition to drinking. Therefore, if we were to talk an emergency in the first few days, 8L can pull you through (in a way) but longer than that, we are going to face big problems.

(Further update by author on 30/8/17:
Actually, the "minimum" requirement of 15L/day/pax is at the upper limit of a range of 7.5-15L/d/c, depending on several factors. See below for a breakdown.)

Alternatively, your water supply may still operate but because of disruption to the water treatment process due to the crisis, the water quality of water from your tap is less than ideal. (In fact, some people already believe this to be so currently, which explains the popularity of water filtration/ purification devices.) Do you have the ability to filter/ purify your water? If you are lucky to have a water filter/ purifier, does it need electricity (which may not be available) to work? If you boil your water, is gas or electricity available?

Figure: My favourite Katadyn Mini - mostly for use outdoors. It can remove particulates and most bugs but not heavy metals, pesticides. However, because it is so light and small, I won't mind bringing it along whenever I head outdoors so when I really need it, it will be there. (Batteries are of course not needed.)

A final question to keep you thinking critically - if there is no water supply, your toilet flush is not going to work. What are you going to do with the loads of bodily waste from your family -  both liquid and solid. Talk about solving a filthy problem.

 I hope that at the very least, this post will start you thinking about the many things we take for granted in civilised society and how fragile many of society's support services are. And if you go ahead to do something about these, all the better.

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.

Some thoughts on the fish kill at Pasir Ris

I must admit I have not been following the news about the recent fish kill at Pasir Ris as close as I should have. But thanks to Ria, her blog posts quickly brought me up to speed on the sequence of events. Here are the links with further links inside the webpages.
  1. Dead fish patrol: Pasir Ris
  2. Any dead fish at Changi?
From all accounts, the situation appeared to be a classic case of eutrophication. Put simply, eutrophication is an excessive growth of algae (sometimes, the term plankton is used though they are not the same) caused by the introduction of nutrients into an ecosystem. Depending on the type of algae, the nutrients may be nitrate, phosphate, silica or others.

Without further information from AVA (or NEA which was strangely silent in this whole episode) about the kind of algae (or "plankton" as given in the media) in the seas off Pasir Ris, I can only surmise that nitrate and ammonia (which can degrade to nitrate) are the probably culprits. In general, seawater is limited by nitrogen so once a sudden excessive input of nitrogen (in the form of nitrate or ammonia) rushes in, the algae immediately makes the best of this bonanza to multiply.

Nitrate is commonly found in fertilisers (yes, it is good for plants too!) and sewage (an decomposition product of ammonia). The question is: who was releasing these fertilisers or sewage? One suggestion was the incidental heavy rains have washed fertilisers or sewage into the sea. Of course, the question remains: where did these fertilisers and sewage come from?

Algae grows fast but they die fast too. Dead algae is major bad news as they decompose, using up dissolved oxygen (DO) in the water. Since many marine organims can only breathe DO, they are in trouble. However, marine organisms are not created equally. Some are more hardy than others since they need less DO to survive.

Wouldn't oxygen from the air replenish the loss of DO in seawater? Yes, it would but the rate of replenishment lags far behind the rate of DO usage in decompostion. Imagine lots and lots of algae dying and taking up DO. Atmospheric oxygen wouldn't have a chance!

Figure: Eutrophication at Botanic Garden (Nov 08). The greenish water is a dead giveaway.
Monitoring by AVA
According to AVA, regular monitoring was in place even before the recent fish kill event (Straits Times Forum 11 Jan 10). When the fish kill occurred, its staff was monitoring daily.

It will be great if AVA can reveal more about its regular monitoring programme - how regular? where are the monitoring stations? What kind of data are collected? For its daily monitoring during the fish kill episode, in addition to the above questions, can AVA reveal the following - what kind of algae was detected in the bloom? Was there a spike in the nutrient levels? What kind of nutrients? What is the trend for DO during the monitoring period?

What about NEA? It has many water sampling stations along the coast. Can their data shed any light on the fish kill? For that matter, NEA has never elaborated on its monitoring programme either i.e. kind of data collected, frequency of collection. Its water quality results have never been in the public domain (except for bits and pieces in its annual report.) (That goes the same for PUB. Have you ever tried requesting for a copy of the analysis report of the tap water that goes to your house?)

Figure: NEA sampling stations in both inland and coastal waters (taken from NEA website a few years back as it no longer could be found currently)

For some reason, water quality data are considered confidential in Singapore. Do such data constitute an issue of national security? Or are the agencies concerned about a vulnerability in their legal position?

Check out the extensive data placed online by the Environmental Protection Department (EPD) of Hong Kong.

Or the data compiled by USGS (U.S. Geological Survey) for the USA.

Wednesday, January 13, 2010

Water trends in the next decade

As we come to the close of the first decade of the new millenium, it is time to do a bit of crystal ball gazing to find out what are in store for the next ten years.

1. Watershed and water quality management using GIS (geographic information system) and other tools
If you are not familiar with GIS (or confuse it with Genome Institute of Singapore), it is a computer database that incorporates geographical information (e.g. locations of petrol kiosks, water quality data) into a digital map. A good example of GIS is Google Earth though there are many other packages (both commercial and freeware) in the market.

With the aid of cheap GPS devices and telemetry, water quality sensors can be placed in strategic locations in a waterbody to provide continuous monitoring of the water quality. Data collected from these sensors can be transmitted via cellular/wireless/radio (aka telemetry) back to a remote server. These vast amount of data will need computing software such as GIS for interpretation into sensible and useful information. A polluting event can signal an immediate alert as monitoring is now continuous and no longer periodic (e.g. once a month). Manpower is also saved in such an arrangement as you do not need staff to go to the field regularly to take measurements. Staff are only mobilised to perform a more detailed investigation when an alert comes in from the remote sensors.

Figure: YSI buoy containing water quality and metereological sensors, telemetry package, solar panels and batteries (

One limitation of such a system is only certain parameters can be measured by sensors e.g. depth, dissolved oxygen (DO), turbidity, electrical conductivity (EC), temperature, pH, oxygen reduction potential (ORP), blue-green algae, chlorophyll, chloride, nitrate, ammonia. In general, these systems cannot measure phospate, bacterial count, heavy metals, pesticides, volatile organic carbon (VOC) etc. all of which exert significant impact on the water quality. (I am however sure that somewhere, somehow, someone is trying to develop continuous monitoring for these parameters.)

Figure: YSI water quality sensor package which can be installed on board YSI buoys. (
A parallel development in water quality monitoring is the use of remote sensing (aerial e.g. spectrographic imager; or satellite e.g. high-resolution imager) to gauge water quality in a watershed. These data can similarly be processed in a GIS. As you probably have guessed, remote sensing suffers the same weakness as telemetric monitoring - it can only assess a few parameters - turbidity, temperature, chlorophyll content etc., and in most cases less than those of telemetric monitoring.

Here is an example of remote sensing of coastal water quality by NOAA (National Oceanic and Atmospheric Administration).

2. Integration of energy and water

In the first place, water and energy are intimately linked. See

With the current emphasis on climate change mitigation, there is a trend towards greening everything by reducing energy usage, including water/wastewater treatment since much energy is needed to process water/wastewater e.g. desalination - reverse osmosis requires high pressures (and high energy input), distillation of seawater is an even bigger energy hog.

Solar energy will be increasingly tapped to power the treatment plant. This is in addition to other energy conservation measures such as green building design. Low technology options include creation of wetlands and reforestation in the plant's vicinity to sequester carbon dioxide. Colocation of power plant and desalination plant is increasingly being explored A power plant typically generates an obscene amount of warm cooling water (originally extracted from the sea) which discharges back into the sea. In colocation, the desalination can receive the warm seawater discharge as its feed, hence lowering the osmotic pressure to be overcome in reverse osmosis.

3. And in Singapore... increasing use of bugs (macroinvertebrates) for biological monitoring of water quality
Even though little has so far been publicised about this issue but the truth is lots of research is currently being carried out to use bugs for an integrated approach to water quality monitoring. In simple terms, the type and quantity of bugs in the water tell you about how good the water is. Obviously, work has to be done to develop useful sampling protocols and biotic indices relevant to this part of the world. Yes, I know USEPA ( and UK ( have very well established protocols and indices in place but are they applicable to Singapore or even Southeast Asia?

The strongest advantage of biological monitoring of bugs are:
  1. You do not need to test each and every chemical to check for pollution. Most chemical pollutants are inherently harmful to bugs so the type of bug community you get will indicate their presence.
  2. Unlike conventional monitoring of physical and chemical parameters, monitoring the bugs will reveal a pollution event has occurred, even though traces of the chemical pollutant have long since disappeared. Bugs will continue to display the effects of the pollutant for some time.
A major weakness...
Bug hunting is fun. Bug counting is NOT. Bringing a sediment sample back to the lab for sorting and counting of bugs can make one buggy. It is tedious and time consuming, causing the sorter/counter to enter a zombie-like state if done in excess.

Figure: Collection of bugs that is sure to thrill any student from primary to tertiary level.

Here are links to some of my bug hunting activities:

The above list is by no means comprehensive or exhaustive. They are what come to my mind based on my context and my experiences.

You may also read my interview on this topic in Straits Times (9 Jan 10).