Photo: Damaged Coastal Plains Highway at Mile 17.5
BELMOPAN, Mon. June 17, 2024
After heavy rainfall over the weekend, early-bird motorists using the recently upgraded US$79.2 million Coastal Plains Highway to save travel time encountered a section near Mile 17.5 that was badly damaged. It seemed as if portions of the pavement had been brusquely shovelled off and some of the asphalt was peeled away. With the Coastal Plains Highway being inaugurated just under a year ago, on July 6, 2023, people questioned the quality of the renovation works done by contractor, Imer Hernandez Development Co. Ltd. The upgrade was billed as climate-resilient, making the damages even more concerning.
Well, today, after the Ministry of Infrastructure had conducted its assessment at the location, it reported that a force of nature, and not the contractor, was to blame for what transpired. Chief Engineer, Evondale Moody told Amandala that the location that flooded had never flooded before, and that several unforeseen factors contributed to the pavement erosion. In comparison, he said, another of the four flood-ways on that highway which also flooded this past weekend (at the Gales Point Village junction) held up well, performing as it should have.
According to the Ministry, a 3.0m x 1.5m box culvert on the approach to Soldier Creek Bridge was overtopped due to backwater from Soldier Creek located about 180m away and also due to blockage of the creek itself (with logs). The Ministry said deforestation and the recent wildfires also led to an increase in the volume of water in the catchment areas surrounding the particular culvert and it was not designed to handle it.
Moody provided further explanation, sharing that the floodwater is supposed to be passing under the bridge, “And so, because of the blockage of the creek, that runoff was diverted to the tributaries that are the inlet for those culverts, instead of going into the creek itself and under the bridge.” The bridge is reported to have a clearance of 10 meters, so Moody says there was “sufficient capacity and hydraulic flow under that structure.” The culverts, on the other hand, did not have such capacity.
Referring to the road works concluded last year, the Ministry shared that, “erosion protection measures in the form of gabion baskets, are present at the inlet and outlet of the culvert; that was not affected, which suggests that the rainfall intensity and flash flood conditions along with debris, greatly impacted the capacity of the culvert …”
The defect liability period for the Coastal Plains road works concluded in April this year, but even if it was still in effect, Moody affirmed that the issue was no fault of the contractor. He reiterated that since the creek was obstructed with logs, the water had to find the lowest point to traverse “and that was through those culverts.” This was compounded by a log that was also obstructing the culvert. He therefore concluded, “It’s not a result of workmanship … That was just the fault of nature. We did not know that the creek would be flooded. We did all that we can within the design to improve the drainage condition within that section of the highway; however, other entities created that problem for us by deforestation upstream of the bridge.” He cited land clearings for development and another deforested site for an eco-park near the Manatee Bridge which used to be the key point for flooding along the Coastal Plains Highway. Looking to the future, Moody said they will now have to assess the capacity of the drains at the Manatee channel “to cope with all that floodwater that will now be coming down because that water will not be infiltrated into the earth anymore; it has to be displaced somewhere and so that has to be to the Manatee Creek.”
As to the integrity of the pavement itself at the approach to Soldier Creek Bridge, Moody explained that it was the traditional paving used in Belize which is the bituminous surface dressing. Moody detailed that this is just “two coats of bitumen with two coats of stone chippings on top.” That’s only about two inches thick and “once water undermines that, it will go.” Moody invited the public to holistically assess the situation noting that the damage was only to about 100 meters (or 0.7 of a mile) of road, whereas the entire Coastal Plains Highway project is 36 miles. He added as well that they took into consideration climate change-related factors when it was being upgraded; and raised the road in that area by two meters, plus introduced the new culverts on the approach to the bridge. Moody commented that if none of those changes had been made, the entire approach would have been impassable after this past weekend.
Expressing shock at the flooding that occurred at that section of the Coastal Plains Highway, Moody remarked, “Definitely, climate change is affecting us significantly; however, we are being affected by other people doing work upstream of these tributaries, which is basically beyond our control; but it’s something that we will now have to monitor because it is affecting us downstream.”
The Ministry and the contractor did remedial works at the location today but for the future, Moody says they will have to consider building another concrete floodway at that section. For now, they are thinking of using a thicker rigid pavement (hot mix asphalt) that will be costlier and is also what is being used for other highways currently being upgraded around the country. In the case of the Coastal Plains Highway, Moody says surface dressing was used because “that was how it was originally designed.” He added, though, that it was not as if it was thin, “because the other highways in the country have the same thing.” According to Moody, the hot mix is three times costlier than surface dressing.
The Coastal Plains Highway project was started in early 2020.