The case of Buhi, Camarines Sur
THE floods that inundated 21 of the 35 barangay in my hometown of Buhi, Camarines Sur, for several days from December 28 until after the new year, might have been caused by heavy rains brought by Tropical Depression “Usman.” But it was certainly one that could have been prevented by adequate and appropriate institutional arrangements and processes.
It is enraging to know that local government units do not have real-time access to rainfall data. This is aggravated by the weak mechanism to mainstream the understanding among local communities about the presence of danger zones and high-risk areas, and of the difference between rainfall intensity from typhoon signals which are functions of wind intensity. Lack of understanding that the lowering of typhoon signals doesn’t translate to weak rainfall, when juxtaposed with the lack of information about the actual intensity of such rainfall, has virtually rendered communities in the affected areas as sitting ducks ready to be drowned.
For Buhi, Camarines Sur, the failure of governance is even more manifest for the simple reason that this town, while having a natural landscape susceptible to flooding, has never had a history of actual floods affecting more than half of its barangay. While Lake Buhi, which is at the center of the town, is fed by several tributaries and has only one outlet, heavy rainfall in the past caused flooding only along the banks, but it did not lead to catastrophic flooding. This is because the town lies at a higher elevation, and any excess water in the lake is eventually drained as it flows out naturally, thereby avoiding a massive breach of its banks. This was so until the national government, through the National Irrigation Administration (NIA), turned the lake into a natural reservoir, where the waters of Lake Buhi were tapped to irrigate lowland rice farms in the fifth district of Camarines Sur. To achieve this, an irrigation control facility was built at the mouth of the lake to regulate the impoundment of water and control its release.
The building of the NIA control structure has effectively transformed the natural draining process of the lake of its excess water from being an act of God into a political and bureaucratic decision. After all, while the controlled flow of water out of the lake reservoir is vital to agricultural production in the affected lowland towns, it can also cause flooding if the gates are fully opened. There was also a need to safeguard the local needs for water by the town. In fact, during the initial stages of the operation of the dam, there was a significant lowering of the water table which severely affected the local water supply. Artesian wells, which were the main sources of water supply of the town prior to the construction of the control structure, went dry. In response, the government installed a piped water system.
The LGU of Buhi insisted that a minimum threshold for water level be identified, beyond which the NIA can be allowed to tap any excess water for irrigation purposes. His was to safeguard the interests of the tilapia industry in the lake. Tilapia farming is an important source of income, and Buhi holds a significant percentage of the market share for tilapia in the entire region. A shallower lake would definitely undermine tilapia production. This is precisely why the LGU opposed the NIA’s proposal that the threshold be set at 79.5 meters by the end of the dry season. The NIA wanted to have a lower threshold not only to enable it to have more water available for lowland irrigation, but also to enable the lake to impound more water when the rainy season comes. This can further assure not only more supply of water for irrigation, but also technically prevent the lake from breaching its banks and prevent flooding during typhoons and heavy precipitation. The LGU, nevertheless, insisted that the minimum threshold be set at 82.4 meters. While this higher threshold ensures a deeper lake favorable to the tilapia industry, it also means that it is closer to the overflow level of 83.5 meters. In short, the risk for the lake overflowing during typhoons or heavy precipitation is now higher, considering that instead of the 4 meters allowance before overflow can be reached which NIA was proposing, the lake is now only 1.1 meters away from overflowing with the current minimum threshold adopted by the LGU.
And this is exactly what happened.
By December 28, the water level of the lake was 84.14 meters which was already 0.64 meters above overflow level. By December 31, the level of the lake was at its highest at 85.65 meters, which is 2.15 meters above the overflow level, and 3.25 meters above the minimum water level threshold set by the LGU. Had this been set at 79.5 meters as per the proposal of NIA, and not at 82.4 meters, the maximum level of the lake would have reached 82.75 meters only which would have still been below by 0.75 meters from the overflow level of 83.5 meters. Had this happened, flooding may have been prevented, if not minimized. The flood gates were ordered opened by December 31, and by that time 21 barangay were already flooded.
Ironically, the LGU of Buhi is obliged to issue warnings to other towns whenever it decides to open the floodgates, but there is no early warning system (EWS) in place with regard to its own residents, advising them of the water levels in the NIA dam, and there is no system of sounding the alarms. There are no flood maps marking the possible extent of flooded areas relative to the level of water in the lake. Consequently, it appears there was no systematic protocol for mandating forced evacuation.
There are other contributing factors that compounded the problem, which includes heavy siltation of the lake. This effectively reduced the actual depth of the lake and consequently the volume of water it can hold. This also resulted in a faster time for the level of the water in the lake to rise and breach its banks. Forest denudation and upland cultivation in steep slopes leads to faster surface water run-off that raises the level of the lake, and soil run-off that contributes to lake siltation. Tilapia culture, which was the reason the LGU insisted on a deeper lake, ironically also contributes to siltation through the accumulation of waste from fish cages.
Certainly, heavy rains brought by Usman were the natural cause of the flooding in Buhi.
It is a fact that we cannot stop the rains.
But it is also a fact that we can prevent floods from occurring in the future, and if it happens, mitigate the damage it inflicts. All it takes are appropriate engineering and environmental measures, like dredging the lake, reforestation, and the adoption of sloping agriculture land techniques. In addition, there is a need to plug the governance deficit by adopting appropriate and sound policy and institutional arrangements and practices. This includes providing the LGU real time information on rainfall data, installing an early-warning system, and revising the protocol that governs the management of the lake as a natural reservoir for irrigation purposes.