A Damming Evidence

In response to Mrs. Monsod’s "Analysis" on GMANews.tv, I have these to say:

1. Timing of the release was dependent upon attaining the end-objective of dam operators which is to fill up the dam. You do not release until you have enough water in the dam. The five days or more of waiting was exactly the time the dam needed to do that.

2. When she said NPC “panicked” and released so much water which caused the flooding, she did not take into consideration that Pepeng came back twice and wreaked havoc upon Northern Luzon three times and, hence, poured an inordinate amount of water than anyone can handle. Common sense will tell us that if you have a full dam, you have no other choice but to “release” as much water as you can to prevent causing damage to your structure. The “panic” came because there was no other move but to “let pass” (not anymore “release”) the surplus water Pepeng delivered.

3. The rate of “release” was not dictated by dam operators but by the amount of water falling into and passing through the dam. It was reported that at first the rate was 500 cu m per second and progressively increased to 600 cms, to 2,500 cms and then to more than 5,000 cms. That, in simple terms, is the better and only logical option than all the water of the dam bursting through a broken dam.

4. Finally, considering that Pangasinan has a total land area of 5,368.8 sq km or 5,368.8 million sq m and San Roque Dam’s watershed area is 9,500 hectares or 95 million sq m, we have a ratio of about 56.5:1. Using official estimates of 80% of Pangasinan as having been underwater, we derive a flooded area of 4,295 million sq m. Using this conservative figure against the watershed area of San Roque, we still have a ratio of 45:1. Meaning, more than 40 times the amount of rain that fell and collected into San Roque Dam eventually and actually fell upon the entire province of Pangasinan and coursed through the waterways, part of it joining the comparatively smaller volume coming from the dam’s spillway and the bigger part going directly into the towns that got submerged. You might feel the sting of a cup of water spurting from a water pistol; but it will not fill up a basin the way 45 cups poured slowly into it will. To put the blame of the flooding on the dam alone is to say that the last straw broke the camel’s back.

Generally, rains fall evenly upon the land, whether up on the mountains or over the plains. That is why meteorologists measure the amount of rainfall by inches or millimeters per day. Area, then, determines volume. This whole issue has not highlighted this fact, but rather focused on a part which is much smaller than what reality presents.

Again, I say that with or without the dam, there would have been flooding because for so many centuries we failed to work within the signs or warnings given to us by Nature that the land can only absorb so much water and that we must allow the rest to flow over wide channels and direct them to the sea without causing damage to lives, lands, farms and properties. A dam mitigates flooding by storing some of the rainfall. It is not a miracle-solution to eradicate our neglect in preparing the land so that it will be spared from disastrous floods.

(Photo above: Calm Subic Bay -- while Typhoon Ramil (a.k.a. Lupit) threatens Northern Luzon, beach lovers were treated to this vista of friendly water, mountain and sky, so far away from the tortured memories of another time, place and story.)