Integrated storm water/flooding management plans will alleviate the problems of water-logging and flooding, but attention must also be paid to civic issues such as keeping the drainage system and streets clean.
Regular flooding and water-logging in our cities indicate that the municipal administration and administrative coordination has collapsed.
Delhi and Gurugram were water-logged again on August 31. A hour of rain brought both cities to a grinding halt. This was not the first time such a situation had occurred; in fact it happens on regular basis. It seems that there is zero accountability and citizens continue to suffer because of the lackadaisical approach of the concerned authorities.
Every time, the blame game starts with no authority taking responsibility. In Delhi for instance, the government, the municipal corporation and the public works department continue to shift the blame onto each other.
One wonders why they can’t sit together to chalk out an integrated and coordinated plan to address the problems of flooding and water logging.
This year, similar flooding has been seen in Bhopal, Mumbai, Bangalore, Nashik and Chennai.
While there can be no control on rains, efforts need to be made to lessen the impact of flooding. In an ideal situation, when it rains, the street drains must keep a city from flooding. But for that, street drains have to be clean, and cleared of leaves and debris. It is the responsibility of the concerned municipal authorities to ensure that.
In many parts of the world, cities have adopted integrated storm water/flooding management plans to lessen and alleviate the problems resulting from water-logging and flooding.
Flood management plans
Flooding in cities is usually approached through the crisis management method. What we need is an integrated storm water/flooding management plan in each city, instead of the traditional storm water management planning. The former is a comprehensive, eco-system-based approach to rainwater management. It would provide direction for future development plans and identify infrastructural needs. The goal of such a plan would be to balance land use planning, storm-water engineering, flood and erosion protection, and environmental protection.
Traditional storm water management planning involves engineer-driven efforts and includes drainage systems, pipe and convey, and the protection of property. It is more reactionary and functions on unilateral decisions, local government ownership, extreme storm focus and peak flow thinking.
However, an integrated approach would be comprehensive and would be driven by interdisciplinary teams to include ecosystems, to prevent problems and protect property and habitats. It would mimic natural processes and function via consensus based decisions in partnership with citizens.
Lessons from the UK, Australia
In the UK and Australia different methods have been adopted to deal with severe flooding.
Temporary or ‘demountable’ flood barriers have been erected to provide additional protection to flood-prone areas. Lightweight sectional metal barriers are relatively inexpensive and can be placed in various configurations and removed completely when waters recede. Frame barriers consist of rigid frames holding an impermeable membrane and use the weight of the floodwater itself to hold the barrier in place.
Natural flood management offers a sustainable approach to managing floods and is intended to complement traditional ‘hard engineering’ techniques, such as flood barriers and concrete walls. These schemes rely on a combination of small-scale interventions with the aim of reducing the speed in the flow of converging water before it reaches larger rivers. Natural flood defence features include small barriers in ditches and fields, or notches cut into embankments, all of which divert the water into open land. Letting pools form outside the main channel of the river means the water is temporarily removed from the main flow reducing the power of the floodwaters.
Trees can also help defend against floods. Planting more trees catches rainfall and helps to remove water from the soil. Large areas must be reforested to make a real difference. Felled trees can also be laid across streams in wooded areas and help push unusually high waters into surrounding woodlands, although such schemes need very careful planning and management.
Sustainable drainage is a concept often applied to towns and cities which are especially prone to flash flooding after sudden heavy rain. In urban areas, large areas of concrete and tarmac, as well as the roofs of buildings, are impermeable to water. Rain is channelled straight into drainage systems which can be quickly overwhelmed. Hence, builders could be asked to landscape developments, so that water from roofs and driveways seep into open ground rather than rushing into the water system. Sustainable drainage entails that impermeable surfaces should be replaced with permeable material, allowing rainwater to drain into the ground – a process known as infiltration. Large ‘detention basins’ can also be built to collect rainwater and hold it, managing the volume of water entering urban rivers, while ponds offer further water-holding capacity.
Role of municipal authorities
What we require is proactive action by municipal authorities to prevent the impact of flood.
Most important, is to keep the drainage system clean on regular basis. This allows water to be carried down fast. One of the major causes for flooding in our cities is that the drains are choked because of solid waste such as construction material, plastics and paper that are thrown in drains. Streets need to be kept clean. As rain-water rushes into the storm drains, it carries solid waste into the drains. Low lands should have storm drains so that water does not get accumulated there.
Rainwater harvesting needs to be encouraged. It would ensure rain water goes to the sub-soil, rather than straining the drainage system. The drains need to be de-silted before the onset of rains to prevent them from getting choked.
Afforestation should be encouraged. Planting trees helps in binding the loose soil and reduces the impact of flowing water.
Municipal bodies of our cities have to come out with consistent and coherent urban policy. Water-logging and flooding is as much a result of incoherent urban policy as it is of poor implementation. In the absence of a coherent urban policy, citizens would continue to suffer and be stranded in their vehicles for hours on a rainy day.
Ashish Joshi, is a civil servant. He is a post-graduate from St Stephen’s College and an alumnus of Indian Institute of Public Administration and National Institute of Financial Management.