Quarries versus water

Quarries versus water

14 April 2011

published by www.newsday.co.tt

Trinida/Tobago — From my own observations in the Cascade Valley from 1967 to the present I know it has taken, on average, five or more serious bush fires to strip a section of hillside of trees – which some deranged person convinced that bush is evil, determined to do, stripping the forest cover bit by bit, dry season after dry season until the only bush remaining is on the extreme south eastern slopes – and even that is threatened by the developers – but that’s another story.

While bush fires set by mischievous youths or careless backyard gardeners can damage the bush that protects land and the watersheds on the topmost slopes of the Northern Range, provided there are no more fires, I repeat, the bush can recover.

However, strip the land of every last vestige of bush, of trees, grass shrubs and herbs and the recovery process can take decades, even a century before the bush reclaims its own. For proof all you need do is to stand on the Queen’s Park Savannah, or almost anywhere where tall buildings don’t obstruct your view of the giant “steps” carved out of the hill above Belmont and the Lady Young Road in 1977 (give or take a year or two). Those giant steps are in fact a quarry where limestone was removed to provide construction materials for the widening and continuation of the Churchill Roosevelt Highway.

Nearly 49 years later herbs are growing on those steps, a few shrubs, one or two trees – and that is all. Rainwaters that once soaked into the ground to seep down to replenish the aquifer under the Queen’s Park Savannah cascade off that bared hill in their headlong rush through Belmont to the Gulf of Paria.

That is but one instance of the damage done by quarries to our sweet fresh water resources – and is the only one most people can see.

But hidden from view in remote valleys of the Northern Range are many, many more quarries.

The public, seeing huge trucks going to and from the quarries, give little thought to the effect quarries have on our water supplies. The country is in desperate need of new infrastructure, of roads to serve rural areas, to alleviate traffic congestion, to improve road communications between our major cities and towns.

Young (and not-so-young) couples need a place to live; families need houses, preferably with backyards where children can play in safety. Given the empty offices (or are they still since at least the Ministry of Foreign Affairs has moved to the Waterfront) Government surely doesn’t need new premises but judging by the steel girders springing up all over the capital, it seems the private sector do.

Quarries supply the materials for our roads, our houses and apartment blocks, our offices, factories, hospitals, schools, clinics, sports arenas … while robbing us of fresh water twice over – once by quarrying in the hills, and again by washing the sands and gravels quarried out of the Northern Basin by backhoes and bulldozers.

You only realise the extent of the devastation, the degradation of that part of Trinidad when you see it from the air. Next time you fly to or back from Tobago try to get a window seat, look down just as the plane approaches, or clears (depending on whether you’re coming or going) the Northern Range and you’ll be appalled at the scars on the landscape. But that’s not the worst where WASA and our water resources are concerned.

By law sand and gravel quarries are required to have settling ponds to remove the soil, the earth, washed out of the sands and gravels before returning the wash water to the river.

Most of the legal quarries that I have seen have settling ponds, but many, if not most are purely cosmetic (for want of a better word).

To explain. The backhoes carry the materials dug out the ground to the wash plant that is situated very close to a river.

Clear water is pumped out of the river and sprayed on the material (the sands and gravels) to wash away the dirt.

The dirty water is drained away to settling pond No1, the heavier soils settle at the bottom of that pond, the rest is allowed to overflow to a next-door pond where finer soils settle to the bottom, the rest flows into the third pond where, hopefully, the last of the soils and sediments, the very smallest particles settle leaving near-clear water to flow back to the river.

In theory, there should be a series of four settling ponds, with the fourth always being out of service for maintenance (cleaning out the silt). When it is clean again it becomes settling pond number three and number one becomes number four, ie is taken out of service for cleaning . That is the theory.

However, I suspect maintaining those settling ponds to be a difficult and expensive operation. In one sand and gravel quarry in Aripo I saw the earth, soil, call it what you will was simply dumped beside the pond – from where, given a good shower of rain, it could wash back in.

And so, far too often and almost without exception in the case of illegal quarries (if there are any after the latest, disastrous amendment to the laws governing quarries that drove a loophole the size of the Gulf of Paria through the regulations to keep our rivers clean and free from silt) … to recap, almost without exception dirty, silt-filled waters from the sand and gravel washplants, pour into our rivers and streams – and down to WASA’s treatment plant – where WASA has had to spend millions maybe billions of dollars to take the silt out of the Caroni water and make it fit for us to drink.

So I leave you with this thought to ponder. If water is life, what price, what is the cost (to you, me, the environment and water resources) of quarrying?

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