JOIN USStormwater drains are inadequate to take the heavy inflow of rainwater beyond a particular intensity. But why let all that water to get out of the area. Why not dig swales along roads to retain/impound the water and also recharge the groundwater?
Simply put, swales are ditches with flat bottoms that collect water. They are usually dug out on the outer contours of a particular landscape to hold and sink the water. This helps hydrate the soil, while preventing water from just running down, often dragging soil with it and filling stormwater drains with silt.
Reasons for flooding
ä Change in land use pattern
ä Inappropriate design approach, construction methodology for structures and maintenance procedures adopted in newly formed layouts
ä Development of land in tank bed areas.
ä Modification of original drain alignment during formation of layouts
ä Non-existence of service roads on either side for laying service lines and routine maintenance.
ä Indiscriminate dumping of debris and solid wastes into drains
ä Dense vegetation growth
ä Encroachment / Modification of original drain alignment
ä Lack of access for routine maintenance
ä Services lines laid inside and across drains
ä Blockage of inlet/outlet location of water bodies
ä Water bodies not functioning as retention basins
ä Sewer lines laid inside and across storm water drains
ä Sewage flow in stormwater drains
Why should SWDs be remodelled?
ä To minimise flood runoff.
ä To ensure free flow of stormwater and to minimize flooding in critical flood prone areas.
ä To improve the health and environmental sanitation conditions in the surrounding vicinity of SWDs and water bodies.
ä To protect the existing waterways and water bodies from environmental degradation.
ä To improve groundwater level by holding rain water in water bodies.
ä To provide alternative water source in case of emergencies by rainwater harvesting.
Benefits from remodeling
ä A properly designed drainage system will ensure reduction in flood incidences which in turn reduces flood damage and traffic hold ups.
ä A properly maintained drainage system with controls on sewage connections and solid waste dumping will reduce pollution of water bodies and groundwater.
ä Proper maintenance of facilities such as rainwater detention ponds and retention basins will attenuate the peak run-offs and recharge groundwater.
äProper maintenance of localised sewage treatment plants and using the treated sewage will reduce the stress on fresh water sources.