…imagining the unthinkable (part 2)…
It was recently discovered that a splay of the West Valley Fault runs underneath the 50 year old Angat Dam that is now needing rehabilitation. The issue is, if the West Valley Fault moves and the dam breaks, what can the scenario be?
The simple animation below was created using data from flood.firetree.net which simulate global rises in sea level and calculate the path that water takes when landscapes are flooded.
If ocean water were to rise and wrap itself round the mountains to reach Angat Dam in the highland, then the natural pathways it takes to rise there are the same pathways that metric tons of water coming down from Angat Dam will also take should the dam collapse. The main pathway that Angat Lake drains to are the interconnected rivers beginning with Ipo Watershed where Ipo Dam is located, (the following is tagged in Google Earth though not necessarily complete and in the correct order) Bitbit River, Bakas River, Kanyakan River, Norzagaray River, Angat River, San Rafael River, and Bustos River that swells in the containment of Bustos Dam.
Based on land elevation as deduced from how the surrounding terrain responds to the simulated sea level rise, there is possibility of an overspill inland at the river bend near Ipo Dam if metric tons of water from Angat Lake breaks through Angat Dam. The path of the overspill seems to point to Norzagaray and/or San Jose Del Monte in the vicinity of Quirino Highway as entry points for the swelling waters (red arrow below).
The same mechanics also help to identify which terrains can act as barrier to the torrential flow of water and, thus, spare Metro Manila which by then would already be hit by a 7.2 magnitude earthquake as experts predict would happen. The propensity of these natural barriers to protect is confirmed by the high elevation of terrains as shown upon close-up of the images above and below.
Map showing Angat Dam amid the municipalities of Bulacan:
Map showing Angat Dam amid the provinces of Bulacan and Rizal: (please be patient while heavy image loads slowly; also don’t forget to click the scroll wheel after zooming-in the image)
The mountain peaks of Montalban (legit historical name that was changed to its now geographical but politically bootleg name Rodriguez) may all be that stand between Metro Manila, which by then may be reeling from the destruction of a megaquake, and Angat Dam, which could inflict further catastrophic damage had not these mountain peaks instead divert the destructive waters and flood to the lowlands of Bulacan.
THIS IS A SCENARIO THAT CAN BE NOT FAR FROM BECOMING REALITY IF THE RETROFITTING AND REHABILITATION OF ANGAT DAM ARE FURTHER DELAYED DUE TO THE SLOW PROCESS BY WHICH THE NATIONAL GOVERNMENT OPERATES.