11 puroks uninhabitable
THE Mines and Geosciences Bureau of the Department of Environment and Natural Resources has recommended that residents of 11 puroks in three barangays in Nabunturan, Compostela Valley be relocated as soon as possible because of unstable ground conditions.
Recommended to be vacated are Puroks 1, 2, 3, 4, 5, 6, 13, 14, and 15 barangay Bukal, Purok 15 of barangay Mainit, and Purok 9 of barangay Magading.
This is contained in the “Results of The Mines And Geosciences Bureau’s (MGB) 1:10,000 Scale Geohazards (Landslide And Flood) Assessment And Mapping Of Nabunturan, Compostela Valley Province” released by the MGB recently along with similar studies in Montevista, Monkayo, Compostela, in Compostela Valley and Manay, Cateel, Boston, and Baganga.
Sun.Star has just read the Nabunturan study and still have to read the others.
The geohazards assessment and mapping of areas within Nabunturan was conducted by the MGB Central Office last March 11-19, 2013.
The team was composed of geologists from the central office, namely, Mr. Salvio B. Laserna, Ms. Christine Jeiselle G. Guarino, Ms. Vanessa Andrea V. Llagas, Mr. Kevin L. Garas, Mr. Mel Anthony A. Casulla and Ms. Princess Danielle B. Matas.
Barangay Bukal has been found to have many debris flow paths, as manifested by large boulders, making the puroks unsuitable for human habitation.
Aside from just relocation of present residents, in Puroks 1, 2, and 3 of barangay Bukal, the MGB recommended constant monitoring of mining operations there and the immediately closure of illegal mining operations.
There are a lot of other areas that have been classified as in high risk of flooding and landslides, but the 11 puroks are the ones that have been recommended to be vacated or as the report said, “Relocation of the present residents should be prioritized by the government.”
For Purok 9 in barangay Magading, the relocation recommended is for residents along the banks of Manat River, which has been classified as very susceptible to flooding.
For residents who are not on the banks, the MGB recommends the development of an early warning device for flood during the season of typhoon and monsoon rains, and a corresponding evacuation plan.
“See to it that evacuation sites are already identified before flood events,” the report said.
The assessment done, the MGB report explained is aimed at “reducing, if not, totally mitigating the destructive effects and impacts of natural hazards on the populace.”
It is also a follow-up on the geohazards assessment and 1:50,000 scale mapping made by the MGB 11.
Areas were classified based on landslide susceptibility as low, moderate, high and very high where low to moderate is between 18 to 35 degrees in slope and has stable soil condition, high has a slope more than 35 degrees with no-cohesive soil matched with poor to very poor rock mass strength, and having traces of past landslides as well as the presence of tension cracks. The very highly susceptible to landslide are those that are not only on slopes above 35 degrees and non-cohesive soil and very poor rock mass strength, but are also the sites of recent landslides and where bulges and terracets are visibly seen.
In terms of flood suspectibility, those classified as Very high/Critical flood susceptibility are areas likely to experience flood heights in excess of 2.0 meters and/or flood duration of more than three days. These areas are immediately flooded during heavy rains of several hours; include landforms of topographic lows such as active river channels, abandoned river channels and areas along river banks; also prone to flashfloods.
Those classified as high are areas likely to experience flood heights of 1.0 to 2.0 meters and/or flood duration of more than three days.
While those moderate are areas likely to experience flood heights of 0.5 to 1.0 meters and/or flood duration of 1 to 3 days.