The Selangor Dam EIA:
More Questions Than Answers
The Department of the Environment
EIA Review
Date: 15th April 1999
Concerned For Sungai Selangor (CFSS)
c/o No. 10, Jalan 7/2
46050 Petaling Jaya
Concern For Sungai Selangor: Our Stand

The Environmental Impact Assessment Report

What Are We Losing

Technical questions on the EIA


Water Crisis Justification

Technical Feasibility Study Report

Hydrology, Hydraulics, Geohydrology

Water Quality  

Terrestrial Fauna

Human Development

Dam Risk Assessment

More Information on Dams

From The New Internationalist

Problems with Dams

Heavy Metals: Effects of Cadmium in Water Supply

 1. Concern For Sungai Selangor: Our Stand

The Environmental Impact Assessment Report

The Environmental Impact Assessment Report [1] on the proposed Selangor Dam is unprofessional in its study. It is a shoddy piece of work. It raises more questions rather than provides answers. Without answers to the questions we pose in the following sections, we cannot make an informed judgement on the Dam’s viability. It is hard to imagine how the EIA can help convince its commissioner, or even the authors of the EIA itself, that the dam is a sound proposal. It, therefore, has not changed our present judgement that the dam is unviable. If anything, the EIA only strengthens our conviction that the dam is not only unviable, it is unnecessary.

As an example of shoddy work, reference 76 is not even listed. And it is the most important reference of all: the technical feasibility report for the Dam.

We have listed the questions posed according to the sections involved. Please refer to our technical questions in section 2. The answers to the  questions are important to determine how the EIA reached its conclusions and recommendations.

Without the answers, the EIA study is an incomplete and an inconclusive piece of work. Without them, the proposed dam must be deemed unviable and must not be built.

What Are We Losing?

Every year, in the last decade, there has been an increase in demand for potable water of 9% for Selangor (including Kuala Lumpur) [1]. If we were to follow this demand, then every time there is a shortfall in water supply, new sources must be found. The trouble is that some of the things we hold dear to our hearts might have to go too!  The fireflies in Kg Kuantan (and probably the community that supports the eco-tourism based on the fireflies), whitewater rafting in Sungai Selangor, the ancestral lands of the Orang Asli which would be innundated by the dam, some endangered species like the serow (kambing gurun), tapir and the panther [1], and the unaccounted for ecological chains of fauna and flora affected by the inundation and the altered flow of the Selangor river once the dam is in place.

And the last, pristine, nature reserve of Selangor.

Where do we draw the line in protecting things dear to our hearts? In fact, there is no drawing-the-line. Every time there is a water shortage, we retreat and resign ourselves again to the fact that a few more precious things would have to go. In the name of development we need to sacrifice - so goes the exhortation. Some proponents of the dam even simplify the issue  to the question of “fireflies or water for humans?”.

The real questions are these:  What are the limits to growth? Where do we draw the line? What are the things that give meaning to life?

Five years down the road, after the Selangor Dam satisfies the present shortfall, the same argument would be given - water or birds, this time?  Where would it end?

The inability to “draw the line” inevitably leads to the point where we no longer need to draw-the-line anywhere: when everything close to our hearts, when everything that conservationists have been struggling for, is sacrificed in the name of development.

To prevent the inevitability of losing everything, we must question the conventional wisdom of growth and more growth - caused by population and development, the two growths that hunger for more water each year.  We must pose the “drawing-the-line” wisdom, i.e., we need an alternative development path.  If there are things we hold dear to our hearts, things that give meaning to the quality of our lives, if these mean that Selangor or Kuala Lumpur can only support a certain size of population and of development, then this is where we draw the line.

Otherwise, we will only end up with concrete jungles and their sterile gardens - if there are sterile gardens at all! And a Kuala Lumpur the size of Jakarta or Bangkok where, in two hours, we would still be in a traffic jam trying to escape the crowded and polluted city. At least, in the present KL (which is already bad enough with its pollution and congestion), in those two hours we would already be in Kg Kuantan marveling at the fireflies, or in Kuala Selangor enjoying the bird sanctuary, or whitewater rafting at Sg Selangor, or just quietly being in harmony with nature somewhere in the wilderness.

It is these little pleasures that make for a good and meaningful quality of life.

If we were to follow the present trend in water consumption, by 2003 all the available water sources of Selangor and Kuala Lumpur would dry up [1].

A growth of 9% in water demand each year means that water consumption/supply doubles nearly every 8 years. Consumption in 1998 is 2500 million litres per day (mld). Thus, in 2006 it will be 5000 mld, in 2014 10,000 mld, in 2022 20,000 mld, and so on. Are we seriously going to follow this kind of development which incidentally pollutes available water resources and further limits fresh water supply?

Before we allow the last line of retreat to be drawn, when no more water anywhere is available, when everything dear to us is gone, why not draw the line here and now, before the damage is beyond repair?  Before everything that gives meaning to life has disappeared?

The regulated water after extraction leaves only a flow of 300 million litres per day [1] in Sg Selangor. This is much lower than even during the dry season. The difference between normal flow and after damming would lead to salt water intrusion inland. This would kill the berembang trees the trees fireflies feed on. Without these trees, the unique synchronous flashing display of fireflies in Kg Kuantan will be lost forever. There are only two such colonies in the world, the other being in Brazil. What a loss for posterity!

Salt water intrusion, too, will destroy land and agriculture around Kuala Selangor. This follows from examples everywhere where salt water intrusion has occurred.

Building the dam has been made the first option. Other alternatives should have been looked into.

Firstly, preventing leaks, either as stolen water or just plain leaky pipes. Some 37% of the supplied water is lost this way. We should emulate Singapore: it achieves only a 10% loss. As McCully says [2], “fix the pipes, spare the river.”  Fixing leaky pipes together with conservation measures by the public, as well as supplementing with underground water extraction could be enough to offset the shortfall. (Of course in tackling water shortages, dam building has more impact than fixing pipes in terms of “doing something”!)  Then if there is a shortfall, only a small, ecologically-sound dam is required.

Underground extraction, however, must be sustainable. Extraction must not exceed replenishment, else the problem of subsidence results. This is a major problem for Mexico City (certain barios are sinking at 30 cm per year), Beijing, Houston (which sunk two meters in 10 years) and many others [2]. Uneven subsidence causes pipes to burst and cables to break and other problems. Costs due to subsidence run into billions of dollars.

By making the dam a first option, the need to institute conservation measures and fixing leaks is lost.  The pressure on the public and the authorities to be prudent is lost.  Wasteful habits will never be curtailed - till the next crisis, maybe..

Rather than the dam, we need a sound, integrated, water-resource management system, and water conservation measures, and even decentralization of population centers. All  are needed. Because once a resource is in plentiful supply, the need to conserve and the pressure to save, are lost.

Development and population are heavily concentrated in the Klang Valley. This draws a disproportionate consumption of natural resources, as well as an uneven distribution of income and wealth from the rest of the country. By putting a limit to population growth and development, other areas can now receive better development. We can ensure a more balanced development for the whole country by pushing development away from the Klang Valley. More capital intensive industries could still come here, but the more labour intensive ones could move out.

Putting these limits in place will ensure the management of water demand growth, which is at the heart of the water crisis.

Technical questions on the EIA


We have severe reservations on the completeness of the EIA and have reservations about whether the project consultants and proponents exercised impartiality in looking at options to the dam due to:

- incompleteness of information in the report(in particular on hydrology
  and water demands)

- inadequate analysis of data (as no data was given, what was the analysis
  based on?)

- the objective and conclusion do not conform - the objective is to ensure
  adequate water supply; thus all options should be considered and compared
  (cost-benefit analysis). However, only the option of where to place a dam
  is considered; and whether the dam or interstate transfer should come
  first wrong conclusions - there was no water shortage in areas served by
  the Sg Selangor during the drought; the shortage was in other areas
  served by dams. The water crisis was also precipitated by poor water
  management, pollution, leaks, theft, and so on.

- misinformation on the situation - the area served by Sg Selangor is
  limited to the northern sector of the Klang Valley (not clearly shown in
  Figure 2.2 - deliberately?) but the analysis for water demand shows the
  Selangor dam providing water to a much larger area (Figure 2.3,
  cross-reference with Table 2.1) in the State of Selangor! Is major
  re-piping taking place?!

We enclose detailed comments. The sections in the text below refer to the sections in the EIA.


PLEASE NOTE: In 1998, total national water supply was 10,221 million litres per day and total national demand was 8,622 million litres per day.  Why was there a water shortage when supply is greater than demand?

Please provide data on the shortfall in water supply for the State during the last drought.

What is the drought potential of last year’s drought? Was the problem of water crisis due to supply or mismanagement of water course, pollution, water theft, pipe leaks?

The area served by the Sg Selangor apparently did not experience a water shortage, so why the focus here?

From exec. summary, (ES-2:)

"Dam construction is due to take three years (2000 – 2003), filling to take two wet seasons (2 years?)" Thus the dam will only be ready and functioning in 2005. That cannot meet the anticipated water crisis projected for 2003.

In addition, dam construction, clearing and building works will potentially result in siltation and increased turbidity downstream. This will affect intake water-quality downstream during the critical anticipated 2003 water crisis year, whilst at that time, the dam will be empty or only filling.

This dam, therefore, cannot fulfill the projected requirements for 2003. Even if it was on schedule, it would not meet the requirements as it would still be filling up. The justification given is for a project to meet “medium term water needs of Selangor”.

2.1.2. Water Supply and Demand Projection

On what basis is Table 2.1 calculated? What is the rate of population increase?

What is the area of supply of the ten water supply areas and their water source?  Figure 2.2 is unclear.

What is the potential demand for the area to be served by Sungai Selangor Dam Treatment Plant?

The analysis given is for the whole of Selangor.

Project Description

What is the basis for minimum compensation release? Will this ensure that the aquatic system and river hydraulics will not be affected?

Fig. 2.3 Water Demand Projection for Selangor.
What is the projection for the area to be supplied by the dam project?


The analysis on options is too brief and does not consider alternative means of sourcing water, only alternative dam sites.

If the issue is to solve the potential water crisis in 2003, then all other options should be considered too. For example, groundwater, rainfall harvesting, reducing leaks through old pipes, changing public attitudes to water wastage, water transfer and others.


On Page 2 – 7, Section 2.5 Project Description a recently completed technical feasibility study report is mentioned as reference no. 76. In the reference list, however, reference no.76 does not exist.

Considering the importance of this report as the basis for the whole project justification, it is incredible that it failed to be noted in the reference list.

It should be included as an appendix to the EIA report and a summary of the findings described in the main report.

The question otherwise then arises:

Does such a report exist?

Although 2.5 is purportedly engineering information based on the report, more importantly, for a feasibility study, we hope the hydrological information is not at a “conceptual level”. It needs to be based on a solid study and research.


In Section "Hydrology and Hydraulics Regime"...

No analysis is shown.

Hydrology is the most important factor in building a dam.

- why no measurements at dam site?
- why only tables given?
- no analysis shown for drought possibility.
- no analysis shown for compensation flow requirements.
- no analysis of flow before and after present dams construction and
- no consideration of impact on estuary ecosystem although this is
  recognised as an important impact in Section 4.4.6. Water volume units
  should all be consistent in S.I. units. Different units M³S-1, Mld, MCM
  etc are used and are awkward to compare; or at least the equivalent in
  S.I. units should be given.

Hydrology, Hydraulics and Geohydrology

The report should include:

- Hydrological analysis of the particular dam catchment and comparison to
  the whole Selangor catchment hydrology.

- Drought analysis for the particular catchment.

- Measurement of discharge at the dam site.

- Hydraulic model analysis should be shown for impact on the river channels
  due to compensatory flow discharged from the dam. Modelling should be
  shown for impact on the estuary. The estuary is important not only for
  the firefly ecosystem but also for fisheries and shellfish culture around
  the river mouth area.

- The impact to the water table due to elevation of water levels in the
  dam, seepage flow and potential affects downstream should be assessed
  quantitatively by modelling groundwater flows.

- Siltation and erosion effects during construction and impacts on the
  river beds downstream should be extended from merely a qualitative
  discussion as at present in section 4.3.8. There should be a hydraulic
  model analysis.

- The Catchment Management Plan as mentioned in the TOR (2) is not
  explained. Only the EMP is given. There is discussion of Catchment and
  Reservoir Management (5.3) and an Erosion and Sediment Control Plan
  (ESCP) but the Plan itself is not given.

- The residual impacts on the hydrology, hydraulics, geohydrology of the
  area is not discussed.


The Model

The data collected in the study is for four stations only Fig. 3.6 (S1, S2, S3, S4). Other water quality is from DOE stations.

For model calibration discharge at the time of sampling water quality must be known. Otherwise, it is not certain for what conditions one is calibrating. However, no discharge measurement at time of sampling is given. In the appendix it is stated that average flow conditions were used for calibration. In Figure C4-3, a value of 9.72m³/l is given for the headwater. How was this obtained? Was water quality sampling carried out at this flow quantity during the study period? If not, what formulation was used to transfer the data to this flow quantity?

What about turbidity model analysis?

The cadmium (Cd) levels at all four stations S1-S4 of the study exceed the DOE Interim Standards by 3 to 6 times. Therefore, it cannot be considered suitable as a public water supply source. How did the EIA team miss this fact?

Drinking water standards for Thailand and the USA give Cd levels of 0.01mg/l as maximum acceptable concentration, and 0.01 mg/l in ambient water respectively. Considering that the hardness of the water samples are less than 25 mg/l the existing Cd levels in the source waters are unhealthy. Cd is a toxic metal and can cause kidney damage when at elevated concentration. There must be detailed investigation to determine the suitability of the proposed reservoir water as a raw water supply and this can have great implications for health. The catchment may have naturally high Cd levels. Attached is downloaded information on Cd concentration standards.


In the flora survey, it was mentioned that a new tree species was found in the dam site area. Only six stems of the species were found within the catchment area (pg 3 – 12).

Considering this new tree species, it is not correct to conclude (pg 4 – 18) that “no rare, endemic or endangered plant species were identified”. It seems as if those who wrote the conclusion either glossed over specific findings of the other team members, or worse, did not even bother to read unwanted facts others have found.

The area is obviously unique if a new species was found. It must be rare indeed.

Considering that only small areas of the catchment were surveyed, which resulted in a new species, the potential for other new species in the area is great.


The analysis of conservation status of the study area and habitats is given by the application of a number of indices.

However, the evaluation of the sub-indices contradicts some of the descriptions given for each sub- index. It is important to correct these, because the evaluation is based on the summary index. Perhaps the wrong conclusion may have been reached.

For example:

Vulnerability or ecological fragility defined as “likelihood of total alteration to the physical characteristics of the habitat………….” and “ability to cope with changes…………”  By that criterion, all areas to be inundated (IA) should be given a value of 10 as there will be total alteration. Only areas not to be altered will be given a value of 1.

Representativeness of Habitat defined such that “the more the habitat has in common with other similar habitats”. Yet it appears that even the rubber plantation is not representative (score = 2).

Scientific value defined as a reflection of its scientific importance for conservation and research. The valuation cannot be made in isolation of other information in the study considering the new tree species found in IA, the scientific value for study of the ecological system must be rated greater than 6.


The cultural importance of the Orang Asli spiritual site and ancestral grounds should be explained so that a proper perspective of the area to the Orang Asli can be appreciated.

The fact that the Orang Asli have always expected the area to be gazetted for them gives the land a much higher value to them than if they knew the land was never theirs. There should be comparisons to other Orang Asli reserve land in Selangor to indicate their plight and the socio-cultural impacts on them.

The Orang Asli have been moved about in the name of development with promises of a better life. These promises have not materialised. It is no wonder that they have decided, for all the promises, that they do not want to be moved this time around just to make way for a water project that does not benefit them, but rather, some faraway people who waste water because they cannot value it.


Section 4.5 on Dam Safety.

RISK ASSESSMENT should be given.

Some data for Terengganu are given.

What are the Seismic events expected due to the dam?

How does this dam design and size compare to other Malaysian dams?

What would the dam failure scenario be like? Who/What would be affected?

Is a contingency plan not necessary if a Dam Safety Review is in place?

Considering the joints and shears at the dam site itself, will this bring increased risk to the dam itself compared to other dam sites in Malaysia?

(See section 3.B on Problems with Dams for a list of the problems, especially on safety.)

  3. More Information on Dams

A. The material that follows has been provided by New Internationalist:

Current follies

The 'conquest of nature' approach to river-engineering creates as many problems as it solves.

Deforestation increases damaging erosion and destroys a river's watershed.

Silt is trapped behind dams, reducing fertility downstream as well as the capacity and life-span of the dam. Downstream silt must be replaced by expensive chemical fertilizers.

Dams always carry the danger of collapse due to earthquakes, flooding or sabotage. Casualties from a dam collapse will be much higher than those from normal flooding.

Riverine fisheries are destroyed as nutrients (fish food) become trapped behind dams and fish are unable to move up river to spawn. Downstream agriculture, with reduced water and silt flow, is subject to much higher dangers of salination (salt-poisoning).

Reservoirs flood the often-fertile land at the bottom of valleys and displace thousands of people to less suitable land or overcrowded urban areas. Large reservoirs, particularly in hot climates, have enormous losses of precious water through evaporation. Irrigation channels spread disease, particularly malaria (300 million sufferers) and bilharzia, or schistosomiasis  (200 million affected).

Diking cuts off wetlands which are natural absorbers of flood and provide a wildlife habitat.

Problems With Dams

The problems mentioned below are largely from Patrick McCully’s book [2]. He did a comprehensive study of these problems. (The EIA put as reference Goldsmith and Hilyard's The Social and Environmental Impacts of Large Dams, a 1986 publication but not McCully's 1996 book, which, in part, continues where they left off.) We list a few of the problems McCully mentions without much elaboration:

Global warming is a wildcard.
There could be a shift in weather patterns which affect rainfall. There could be more rainfall or less. More would mean dam safety and breaching conditions need greater safety limits. Less would mean the dam is useless. Already we are seeing a shift in rainfall pattern from the dam catchment areas to the Kuala Lumpur built up areas. Have the built up areas changed the pattern? Or is global warming already playing a role? We are now seeing the paradoxical situation where rain is falling almost every day in the city, yet water levels in our dams are falling.

Shouldn't there be more studies first to look at this phenomenon before the Selangor Dam is built? We could have another costly structure, RM1.96 billion, blotting the environment, but quite useless in its purpose.

McCully listed many dams not meeting its forecasted filling capacity. To name a few: Buendia-Entrepenas, Spain (less than half filled. In 1994, 17% filled); Thailand's 25 largest dams total of less than half filled in 1991, but worsened to only one-third in 1992; Colorado Storage Project (projected flow of 17.5 million acre-feet vs 11.7 million acre-feet actual); Sardar Sarovar on the Narmada River, India (27 maf vs 22.7 maf).

Sedimentation reduces storage capacity:
Sanmenxia Dam, China, a planned 1,200 megawatt storage became a 250 MW actuality; Yangouxia Dam, China lost one-third of its storage capacity, even before it was commissioned! Kulekhani Dam, Nepal, completed in 1981 will be useless by 2000, even though it was predicted to last between 75-100 years; A 1990 World Bank working paper on India's dams concluded, "It is now obvious that the original project estimates of expected sedimentation rates were faulty, based on too few reliable data over too short a period."

Reservoir Induced Seismicity:
This is earthquake induced by a huge body of stored water. There have been RIS in more than 70 dams. Most severe cases are reported for dams higher than 100 meters (Sg Selangor Dam will be crested at 110 meters) but even dams half this height are also believed to be vulnerable. Hoover Dam, USA (221m) experienced a 5.0 sized earthquake on the Richter scale; Koyna, India (103 m), a 6.3; Aswan, Egypt (111m), a 5.6.

Is it true that the Kenyir Dam experienced an RIS of 2.5 to 4.6 on the Richter scale? What are the possibilities of the Selangor Dam experiencing RIS?

Dangerous dams and Decommissioning:
Dams become old, their structures become weak as time goes by, and sedimentation makes them useless and dangerous. In 1987, a survey of US Federal dams concluded that one-fifth of the Bureau of Reclamation's 275  dams are unsafe, as were one-third of the 554 dams operated by the Corps of Engineers. In 1975 in Henan Province, China, a dam burst killing 250,000 people. 17 dams failed between 1990-95.

As John Lowe III and Wilson V. Binger, partners of New York consulting engineers TAMS, say, "When a big project has troubles, they may well be big troubles."

Old dams then need to be decommissioned (defined as anything from stopping electricity generation to removing it completely and restoring the river to its pre-dam state). This problem has not been discussed much by dam proponents (probably pretending it is not there). Hydropower Reform Coalition "believes that removing a hydrodam will cost more than building it." Even dredging costs to remove sediments run into million of dollars from experience in the US.
Cost and time overruns:
In Table 9.3 McCully listed some 30 cases of cost and time overruns. A sample: Three Gorges Dam, China, estimated, $10.7bn, actual $30-50bn; Narmada, Rs42bn, latest estimate Rs342bn; Itaipu, Brazil, $3.4bn, actual $20 bn.

There are other weighty problems - ecological, water-borne diseases (malaria, bilharzia, Japanese Encephalitis, etc) - listed by McCully which we will not go into because of time considerations.


[1] SMHB Sdn Bhd, “Detailed Environmental Impact Assessment Study for the Proposed Development of Sungai Selangor Dam in Hulu Selangor,” 1999.

[2] Patrick McCully, Silenced Rivers: The ecology and politics of large dams, Zed Books: London & New Jersey, 1996