Structural damages in China as a result of flooding
With just two months away from the official start of the rainy season, which is predicted to begin at the end of May its that time of the year where residents of Trinidad and Tobago, begin the process, well lets just say it marks the start of flood season, and we must prepared since this poses a major daily challenge to our entire country.
A flood according to the Office of Disaster Preparedness and Management is an accumulation or an overflow of an expanse of water that covers or inundates land that is usually dry.
Flooding in the capital City of Port of Spain.
With the main types of flooding experienced in Trinidad and Tobago being –
Riverine flooding. This usually occurs when a river overflows its banks. It is usually due to the volume of water within a body of water, such as a river or lake, exceeding its capacity and overflowing its banks. It can also occur when the velocity of the river is so high that it flows right out of the river channel, usually at bends.
Flash flooding. This is a flood that rises and falls rapidly with little or no advance warning. Flash floods usually result from intense rainfall over a relatively small area.
Residents evacuate their home in Tacarigua.
Urban flooding This occurs as a result of land development. Permeable soil layers are being replaced by impermeable paved surfaces, through which water cannot infiltrate. This leads to greater runoff being generated, which can make rivers out of roadways and ponds out of car parks.
Flooding may be caused by a number of factors which could be anthropogenic or natural –
Prolonged rainfall. When rain falls for a prolonged period of time, the soil can become saturated. When water is unable to infiltrate into the saturated soil, it is forced to flow over the soil, thus increasing surface runoff.
Intense/Heavy rainfall. When rain falls heavily; the rain drops hit the ground with a force. This can cause the rain drops to bounce off the soil instead of infiltrating into the soil. The water from the rain is then forced to flow over the surface instead, thus increasing the surface runoff.
Deforestation. The lack of vegetation encourages water to flow over the surface rather than infiltrate into the soil thus increasing surface runoff.
Poor land use practices. Slash and burn agriculture, over-cultivation and over-grazing eventually cause the soil to become infertile and unable to sustain vegetative growth. Consequently, the lack of green cover encourages water to flow over the surface rather than infiltrate into the soil thus increasing surface runoff.
Urbanization leads to the replacement of permeable soil with that of an impervious layer of pitch and concrete, through which water cannot infiltrate. This results in increased surface runoff which leads to flash flooding. This is further heightened by unregulated construction thus country.
Improper waste disposal. Oftentimes, garbage that is not properly disposed enters into drainage systems and clogs drains. This obstructs the free flow of the water that enters into these drains causing water to back up during rainfall flooding the surrounding area. A build up of garbage can also obstruct the natural flow of water in rivers and streams.
Flooding in Philippines due to deforestation
Quarrying is the clearing of land for the removal of aggregates (mainly sand and gravel) which is to be utilized in the construction industry. The action of quarrying leaves land bare and devoid of any trees and shrubs hence increasing surface runoff produced.
Flooding poses a number of health risk, damages to land and property, displacing residents, cause loss of income, destroy crops and kill animals and hinder business activities in cities and towns.
In the overall sense floods leaves residents vulnerable. This is why the regional corporations across the country especially Diego Martin Regional Corporation are taking a proactive approach to the reality of this twin island Republic, and have launched its 2nd “All Hands on Deck” programme on February 23, 2015. A programme that seeks to treat with the cleaning and maintenance of secondary drains and minor water courses that fall within the jurisdiction of the DMRC.
Similar programmes has been ongoing in many other regional corporations in collaboration with the Ministry of Environment and Water Resources who responsible for the cleaning and maintenance of all major water courses.
Flooding in Afghan Northern Province
Flooding is an issue of great concern around the world just last week Afghan officials reported the death of 5 people and destruction of 500 homes displacing millions of residents in the north province of Baghlan due to heavy flooding, that marked the start of Afghanistan’s annual flooding season as snow from the northern mountain range melts. The officials have also stated that the severity of the floods over the past 5 years are due in part to deforestation and environmental degradation.
Long-term methods of flood alleviation and minimization of damages can be achieved through:
Public education this would increase the population’s awareness of the hazard and how they can mitigate against them.
Proper land use and pollution policies and enforce. This would encourage sustainable development by reducing deforestation and illegal quarrying that occur frequently in this country.
Dredge rivers and waterways regularly to remove the excess build up of silt and soil sediments.
Construct and maintain proper drainage systems. Ensure that there is proper drainage or expand on existing drainage systems whenever there’s new settlements or structures being constructed. One of the major causes of flooding in the capital City of Port of Spain is the lack if proper drainage.
ODPM, 2015. found at http://www.rs.nato.int/images/stories/flood.jpg accessed on 6 April, 2015
Trinidad and Tobago Newsday Monday 6 April, 2015
Environ Solutions powered by wordpress.com