THE impact of severe tropical storm “Vinta” (Tembin) has revived the issue of the impact of quarrying and the need to dredge the river that runs through the heart of the country’s emerging 4th metropolis.
Quarrying and dredging are contentious issues. Both are environmental protection and business propositions.
Waterways have carrying capacities. The depth of rivers, for example, are affected by silt run-off from denuded mountain landscapes. Human activities along the river may also loosen earth materials on rivers causing silt deposits downstream.
Siltation results in shallower rivers. Shallow waters easily overflow. As they say, in shallow Cagayan de Oro river, flashfloods are caused by three horses peeing upstream after a night of overflowing booze.
In the aftermath of “Sendong” (Washi) in 2011, experts had blamed shallowing and constriction in certain parts of the Cagayan de Oro river due to siltation and accretion. Both are results of loose earth going the waterway which accumulated over time. The Department of Environment and Natural Resources (DENR) studies some 10 years ago indicate over a billion cubic meters of silt and accretion resulting in river deltas like the Isla de Oro in the Cagayan de Oro River.
Cala-cala, an accretion of the Cagayan de Oro River in a bend at barangays Macasandig and Balulang and Isal de Oro were smoothered by violently rampaging water of Sendong. A year later, it was further inundated by “Pablo” (Bopha) and last December, by Vinta. As I have written earlier, Cagayan de Oro is the unlucky recipient of the new normal in a climate changing world — three 100-year cycle floods in six years.
Before Sendong, the Mines and Geosciences Bureau (MGB) have marked these and other areas along the Cagayan de Oro River as flood hazard areas. It had in fact recommended that these be declared “no-build zone” and for these land to be removed or quarried.
For those in the construction industry, removing these massive appendices of the river bank is a very good business proposition. In the “build, build, build” era, these would become a source of abundant, affordable filling materials and concrete aggregates.
On the other hand, environmentalists have blamed siltation and accretion of the river to deforestation and quarrying. They argue that quarrying the river bed loosen earth that eventually contributes to shallowing downstream. Studies have indicated that for every scoop of earth loaded in a truck, an equivalent of three scoops of loose earth is carried by the current downstream.
Both are valid proposition. Considering both could result in a chicken-and-egg dillema.
I would then propose that rather than banging the heads of environmentalists and those in the construction industry, a dialogue should be made to come up with win-win solutions.
I am sure there are available technical measures to mitigate siltation caused by quarrying.
There is also a need for the removal of river obstruction like the Cala-cala accretion, the river deltas, the silt accumulating in the unfinished dikes and dredge the mouth of the river. The study for the removal of the river deltas is still undergoing study and eventually green light from the Department of Public Works and Higways (DPWH). Removing the Cala-cala accretion has also become complicated because the Macasandig-Balulang bridge. Just like the river deltas though, it is up for the DPWH if it will exempt quarrying near bridges the Cala-cala areas.
There is also the need to reforest the vast watershed — 135,000 hectares — of the Cagayan de Oro watershed and promote urgently sustainable agriculture practices that gives primary consideration to soil conservation.
Let us solve one-half of the problem by talking.