The recent flood problem in Alor Setar and Jitra

In my parting message as PTA Chairman in Keat Hwa magazine I was telling my friends (i.e. teachers, students and fellow Board/PTA Members) that from now on, I will regularly update my blog. But somehow to overcome the inertia to write is tremendous. Engineers somehow are people who act more than write. Nonetheless I will write now and I will begin on the current issue of flood problem in North Kedah. This flood that we experienced is worse than 2005 one; much larger areas were flooded and to a deeper depth. Some areas in Jitra were flooded to the roof (single storey) while the deeper area in Alor Setar were about 1.2 m. Is it really an event that comes once in 100 years as some authority people have said in the newspaper? Not likely, as we have experienced this order of magnitude of flood 2 times in the past 10 years.

Looking through the rainfall records from MADA’s website on rainfall and water level, there is no doubt that the flood in Jitra and Alor Setar is due to extremely heavy rainfall on the 1^st and 2^nd of November. The Sungai Bata catchment has experienced generally 200 to 300 mm of rainfall for those 2 days and the rainfall in Sungai Padang Terap is similar.

However besides the heavy rainfall, there are a few other reasons for the occurrence of this extreme flood event, such as:

1) The lack of control on the felling of trees in the upper catchment of Sungai Bata, leading to low moisture retention by the catchment and excessive soil erosion resulting in the reduction of river channel section.

2) The practice of direct seeding paddy planting culture has resulted in large amount of soil/silt, flowing into the river where farmers have to ‘dewater’ the paddy field for sowing. This practice has been on going for more than 20 years and the silt that has gone into the river is tremendous.

3) There is no serious de-silting work carried out for the two rivers i.e. Sungai Bata and Sungai Padang Terap/Sungai Anak Bukit for many years (>20 years). By right to maintain the flow capacity and detention volume of the river, the rivers should be de-silted regularly, maybe once in 5 years.

4) The construction of North-South Highway and upgrading of Alor Setar/Kepala Batas/Jitra Highway without adequate drainage culvert crossing the highway had impeded the flow of water towards the sea through the paddy field by plot to plot mechanism.

I believe the government needs to take serious action on the above to reduce the impact of the flood.While a comprehensive flood mitigation plan will take time, some immediate action to build low level bund(~2 m) along some stretches of the river and installation of non return flap gate on some drainage outlets to the river should take place immediately. The judicious operation of the existing pumping station like Sungai Raja could also protect city centre from the unnecessary flood.