Cleaning Drains, Waterways Part Of Our Efforts To Mitigate Against Impact Of Climate Change
waterways part of our efforts to mitigate against impact of climate change
Some flooding that we are seeing in parts of Fiji hit by heavy rain is caused by a poor drainage system.
With the kind of weather systems that we are now experiencing, we are vulnerable to flooding.
According to Geoscience Australia, flooding occurs most commonly from heavy rainfall when natural watercourses do not have the capacity to convey excess water. Blocked waterways or drains are two of the common causes of flash flooding here.
The water cannot flow through so it spills over to the adjacent area.
There has been a chorus of complaints from farmers and ordinary people about how easy their land, properties, farms and roads get flooded now.
The wet weather events we are getting should come as no surprise. It was originally forecasted for this cyclone season.
The frequent wet weather means that dry soil become inundated. It absorbs water until it reaches saturation point.
Surplus water then builds on the ground and if rain persists, it will rise and threaten people, buildings and crops.
To rectify the situation, proper drains should be constructed with appropriate outlets where water flows and reduces pressure and water build-up.
Blocked drains should be cleared before a rainy season. They will minimise the risks of flooding. These are simple mitigating factors that we need to seriously take into consideration and do something about it.
Geoscience Australia says, however, floods are not always caused by heavy rainfall.
They can result from other phenomena, particularly in coastal areas where inundation can be caused by a storm surge associated with a tropical cyclone, a tsunami or a high tide coinciding with higher than normal river levels.
Dam failure, triggered for example by an earthquake, will result in flooding of the downstream area, even in dry weather conditions.
Other factors which may contribute to flooding include:
volume, spatial distribution, intensity and duration of rainfall over a catchment;
the capacity of the watercourse or stream network to convey runoff;
catchment and weather conditions prior to a rainfall event;
topography; and tidal influences.
Flooding, particularly in our river floodplains, is as natural as rain and has been occurring for hundreds of years.
The fertile valleys of Naitasiri, Tailevu through Wainibuka, Sigatoka, Namosi, Navua, Ra, Tavua Ba and Nadi in Viti Levu and similar areas in Vanua Levu have supported our agriculture for hundreds of years. This is because flooding has left nutrient-rich silt deposits behind.
We are in the throes of the impact of climate change. It will hit us whether we like it or not. What we need to do is to do all we can to mitigate its impact.
We can start with our drains and waterways and ensure that we keep our environment clean.