The following information was presented to the citizens and Government of Trinidad and Tobago at a press conference on November 17, 2017. It followed an extreme and destructive rainfall event. It is repeated here for public edification.
Glaciers across the earth, the Arctic and Antarctic, the Himalayas, Kilimanjaro, the Andes are melting. This is scientific and irrefutable. Where does all this water go? It fills up the sea. Megatons of atomic energy, otherwise known as hurricanes, are built up from a hotter and fuller Atlantic. Water inches up on land in what we call sea level rise. Higher and middle slopes of mountain chains are left without their perennial supply of water. Drought, dry weather, and so bush fires occur on slopes and foothills. Lower than the foothills, on basins and plains, we have flooding. More “loosened” water in circulation, on land, seas, lakes, atmosphere, lead to extreme precipitation. This leads to landslides on terrain affected by “development”: housing, mining, road infrastructure, quarrying and so on.
That is the meaning of extreme weather events: increased energy and frequency of hurricanes; sea level rise; drought; bush and forest fires; flooding and landslides. The pattern of extreme weather changes is logical but unexpected. Some places which have historically experienced bush fires might now be perennially wet, green and waterlogged, for example.
1. The Orinoco Flow: Global warming has led to the melting of icecaps and glaciers on mid and lower slopes globally. The source of much of the floodwaters around the South, East and South-Western Coasts of Trinidad are the Andean glaciers, whose waters flow into the vast Orinoco Basin, through the delta and riverine formations there, surging into the Columbus Channel and embracing Trinidad. In the rainy season, this surge is rough and intrusive. The melting of glacial ice means that there is more loosened water in the hydrological system.
2. Inland Flows: During the rainy season, at high tides, this water pelts up the large rivers of Trinidad. The Godineau or Oropouche River, the main artery of the Oropouche Basin, is particularly susceptible to this flow. Such other rivers, draining the Nariva and Caroni Basins are the Nariva and Caroni Rivers.
3. Outflow Retention: Increased warming of the hydrosphere (oceans, rivers, lakes, glacial ice and icecaps) causes increased evaporation and increased precipitation. When extreme precipitation occurs, water is loaded onto the basin, particularly in low-lying areas. At high tide the water backs up the main artery of the Basins; while its free access to the sea is denied. With nowhere to go, the water spills over the river banks, the arteries, and flows onto the land.
4. Sheet Flow: Water flowing across the land flows in sheets, a phenomenon called sheet flow. It is very difficult for hydraulic systems to trap sheet flow. Sheet flow water does not move obediently into channels laid by man.
5. Blockage and Displacement: Large obstacles, embankments, interchanges, highways laid North to South across the direction of sheet flow, and large settlements block and displace water; displaced water attacks homes, farms, roadways causing dramatic social (including disease), economic, ecological and financial losses.
6. Disrepair of Gates: If the system of gates which ring the ‘ramparts’ of the Basins, in order to control the inland and outland flow of water are not maintained the flooding is aggravated.
7. Natural Susceptibility: Our Basin systems are swamp/delta formations. They are dynamic and complex hydrological, morphological and biological systems. Historically, perennial floods have served to invigorate, cleanse and stabilize its biotic life. Farmers and residents who understand and respect the system accrue sustainable economic benefits from it. Much of this land is under sea level at mean to high tides. It is susceptible to massive flooding impacts.
1. Modernize Floodgates: The flood gates along the mangrove fringe which control inflows and outflows of water from the sea should be modernized, using electronic technologies, and put back to work.
2. Hydrology before Hydraulics: Hydrology, that is a scientific understanding of the behaviour of water in its total biosphere (land, sea, air), must be understood before hydraulics could be designed.
3. Retention Ponds: Retention ponds should be built at vulnerable areas to control superabundant floodwaters. Water from these ponds should be used for agriculture in the dry season; that is in an era of climate extremes. These ponds should also be built on the foothills of the Northern Range on the North Caroni Plains.
4. Hydrological Studies: The development of Hydrological Studies programmes at our local universities is needed. Water control and management and mitigation will be permanent features of our future economy.
5. Local Government Reform – Constituency Government: All floods have a global origin, a local impact. The impacts are best managed locally, by local citizens and organizations. Standard operating routines for medical, rescue, disease control, transport, shelter, communications, blockage and food storage must be developed.
6. Rainwater Harvesting Technology: Large volumes of the water in the hydrosphere, from cloud to rooftop to ground, may be converted to domestic, industrial and farm water.
7. Horticulture: Forests and stands of trees intercept water and draw up and store large volumes of water. A dedicated horticultural transformation involving local communities, seed banks for food and crop bearing trees, and large forest species, like silk cotton and samaan, is a necessity. This will also mitigate wet-weather landslides which will become increasingly common.