Urban Floods In India
Over the last 15 years, there has been a constant rise in the urban floods across cities in India including Chennai (2004, 2010, 2015), Srinagar (2014), Jamshedpur (2008), Kolkata (2007), Bangalore (2005), Surat (2006), Mumbai (2005), Delhi (2002, 2003), and Ahmadabad (2001) , Recently Mumbai ( 2017).
A flood is an overflow of a large amount of water beyond its normal limits, especially over what is normally dry land.
Flood may be
1. Areal ( Floods can happen on flat or low-lying areas when water is supplied by rainfall or snowmelt more rapidly than it can either infiltrate or runoff. The excess accumulates in place, sometimes to hazardous depth)
2. Riverine (Channel) overflow
3.Estuarine and coastal
4. Urban flooding
5. Rural flooding
Urban flooding is different from rural flooding as urbanisation leads to developed catchment areas which increased the flood peaks and flood volume . Urban areas are densely populated and witness loss of life and property , disruption in transport and power and incidents of epidemics.
Damages from urban flooding can be grouped into two categories:
Direct damage —typically material damage caused by water or flowing water.
Indirect damage —social consequences that are negative long term effects of a more psychological character, like decrease of property values in frequently flooded areas and Arise IAS delayed economical development, for e.g. traffic disruptions, administrative and labour costs, production losses, spreading of diseases, etc.
Causes of Urban floods
1.Unplanned urbanisation Causes increased volume and rate of surface runoff from developed lands, which leads to more flash flooding and increased extent, height and frequency of flooding.
2. Development in flood-prone areas leads to encroachment and alteration of floodplain which in turn reduces flood storage capacity, increasing downstream flood.
3. Increase of impervious surfaces like roads, roofs means more runoff.
4. Inefficient and non- upgraded drainage system leads to blockage
5. Pollution :: Litter, building debris, sediments and solid waste are the main causes of blockages of the drainage system and subsequent flooding. There has been an explosive increase in the urban population without corresponding expansion of civic facilities such as adequate infrastructure for the disposal of waste. Hence, as more people are migrating to cities, the urban civic services are becoming less adequate. As a result, almost all urban water bodies in India are suffering because of pollution. In many cases the water bodies have been turned into landfills.
6. Lack of political accountability of all levels of Govt.
7. Lack of coordination among agencies
8. Attitude of people :: do not pay attention towards early warnings and consequences of illegal constructions in low lying areas.
9. Deforestation :: large areas of forests near the rivers/ catchments of cities are being cleared to construct settlements , farmlands due to which soil quickly lost to drains.
10. Political neglect:: even 40 years after the India’s 1st and last commission on floods was constituted , the situation has not improved.
– No national level flood control authority
– Rashtriya Barh Aayog (RBA) was set up in 1976 to study India’s flood control measures after the projects launched under NATIONAL FLOOD CONTROL PROGRAMME of 1954 , but failed to achieve much success.
– In 1980s , RBA made 207 recommendations and 4 observations::
a) That flood is due to anthropogenic factors
b) It questioned effectiveness of methods adopted and suggested to halt embankments
c) Demanded for consolidation between centre and states
d) Recommend dynamic strategy to cope with changing nature of floods.
Also suggested to accurate estimation of flood prone areas and timely evaluation of flood management projects.
Lack of willpower to take action on recommendations of evaluation reports is the problem.
In 1981 , the Govt.accepted all RBA recommendations and circulated them to the states. However between 1987-2001 expert committee reviewed that implementations and found that they had not been implemented. It concluded that international and inter state issues , fund constraints , populations pressure and lack of infrastructure were the main difficulties.
11. Shrinking water bodies : Delhi-based non-profit Centre for Science and Environment’s research shows that Chennai had more than 600 water bodies in the 1980s, but a master plan published in 2008 said that only a fraction of the lakes could be found in a healthy condition.
Lakes store the excess of water and reduce the flow but encroachment to catchment near water bodies leads to destroy them and thus flooding.
12. Illegal mining activities: Illegal mining for building material such as sand and quartzite both on the catchment and on the bed of the lake have extremely damaging impact on the water body. For example, the Jaisamand Lake in Jodhpur, once the only source of drinking water for the city, has been suffering from illegal mining in the catchment area for the last 20 years, despite a court order to stop mining in 1999. Badkhal Lake in Faridabad has dried up in the same way. Unmindful sand mining from the catchment of Vembanad Lake on the outskirts of Kochi has lowered the water level in the lake.
13. Unplanned tourism activities: Using water bodies to attract tourists has become a threat to several urban lakes in India. Tso Morari and Pongsho lakes in Ladakh have become polluted because of unplanned and unregulated tourism. Another example is Ashtamudi Lake in Kaerala’s Kollam city that has become polluted because of spillage of oil from motor boats.
14. Absence of administrative framework: The biggest challenge remains the government apathy towards water bodies. This can be understood from the fact that the government does not even have data on the total number of urban water bodies in the country. Few cities have recorded water bodies because of court rulings. A 2010-11 Comptroller and Auditor General of India report on the plight of 22 lakes in 14 states said: “MoEF&CC (Union Ministry of Environment & Climate Change) had not identified wetlands associated with each river/lake and no identifications of risks to these wetlands due to pollution of river water/lake water had been carried out by CPCB (Central Pollution ControlBoard). Further, CPCB had not identified the major aquatic species, birds, plants and animals facing risks due to pollution of rivers and lakes.”
Effects of Urban flooding
The flooding affects every section of people, systems in a city, some of them are summarised below:
Economic effects :
• Damage to Public buildings, Public utility works, housing and house –hold assets.
• Loss of earning in industry & trade
• Loss of earning to petty shopkeepers and workers
• Loss of employment to daily earners
• Loss of revenue due to Road, Railway, Transportation Interruption
• High prices for essential commodities.
After flooding, government has to put many resources for aiding e.g., police force, fire control, aid workers and for restoration of flood affected structures, persons, live-stock etc.The flooding cause a great economic loss to the state, individual and to the society.
Environmental effects: Damage to surroundings, forests, ridges, wild-life, zoo, urban community-trees, water bodies, shrubs, grass, fruits/vegetables in go downs etc result imbalance of eco-system of the city. Effects on traffic: Flooding results in the damages of roads, collapse of bridges causing traffic congestion which affect day-to-day life and other transportation system.
Effects on human beings:
● Human lives : Every year floods in India cause more than 50 lac people affected dead and become homeless.
● Psychological impact : The people of all ages who stranded in flooding suffer a great Psychological impact disturbing their whole life and the society as whole.
Effects on livestock : The live stock is the most affected living being due to urban floods. It is difficult to care for them particularly when human being itself is in trouble.
Diseases : Flooding usually brings infectious diseases, e.g. military fever, pneumonic plagues, dermatopathia, dysentery, common cold, Dengue, breakbone fever, etc. Chances of food poisoning also become more where electric supply interrupted in food-storage area due to flooding.
Public inconveniences: The flooding causes impairment of transport and communication system due to which all people of all section get stranded e.g. school children, college students, office goers, vegetable, milk venders etc. The basic and essential commodities also do not reach to the common person. This result either starvation to poor persons or high priced to the common persons.
What should be done ?
1. Scheduled Drain Clearance: Until such time as drain inverts are redesigned for self-cleansing velocities and solid waste programs are implemented, ongoing regular clearance of drains is necessary to minimise flooding risks.
2.Water Quality Improvements: At present, the principal causes of poor water quality are the sewage flows and large solid waste content in the drains. The sewer rehabilitation program would involve sewerage of unsewered premises , repair of sewer leak and upgrade of sewer capacity.
3.Capacity building using hydrograph techniques, hydraulic analysis of channels, culvert and pipes, using basic and backwater techniques, planning and design for major and minor drainage systems and powers and duties relating to drainage and planning legislation
4. Community based disaster management system
5. implementing land use planning , construction laws and development controls , strict adherence to enforcing legislations.
6. Education and Consultation: Environment education programs through schools, colleges, NGO’s and mass media to raise community awareness and understanding of the risk of flooding, the importance of clean waterways
7. Collection of good quality data about topology , about water bodies and other structures.
8. Improvement in Early warning system : broadcast could help people to plan their movement and dramatically reduce hardships.
9. Flood water can be stored for using during non-monsoon seasons with adequate infrastructure and proper planning including functional drainage system .
10. Best management practices : sediment fences, re-vegetation, sediment barriers, graved channels, dimension channels etc .
11. Restoration and conservation of water bodies along with green area development.
12. As recommended by RBA State should legislate on floodplain management , particularly encroachment and floodplain zoning ( demarcating floodplains into zoning ) . But apart from Rajasthan and Manipur no state has enacted laws on floodplain zones and argue that such laws would hinder development. Issue should be addressed .
13. As recommended by RBA , states should focus on maintenance of completed work rather than constructing new structures. In Assam, for instance over 4,470 Km embankments were constructed till 1970s. Over 90% of these have outlived their life and need maintenance. As flood prone areas are increasing , there is unprecedented pressure on Govt. To find a solution. Mindless urbanisation, encroaching upon and filling up natural drainage channels and urban lakes and water bodies to use the high-value urban land for buildings, illegal colonies and industries, increase in paved area are the main reasons of flooding, which should be considered.
Facts for prelims::
● Central Water Commission is a premier Technical Organization of India in the field of Water Resources and is presently functioning as an attached office of the Ministry of Water Resources, River Development and Ganga Rejuvenation, Government of India.
The Commission is entrusted with the general responsibilities of :
● initiating, coordinating and furthering in consultation of the State Governments concerned,
● schemes for control, conservation and utilization of water resources throughout the country, for purpose of Flood Control, Irrigation, Navigation, Drinking Water Supply and Water Power Development.
● It also undertakes the investigations, construction and execution of any such schemes as required.
● Flood Monitoring and Forecast dissemination.
● Monsoon was active over different regions of India especially in Gujarat, Eastern Uttar Pradesh, Western Bihar, Assam and lately in West Bengal during mid July 2017..
Satellite plays important role in detection and monitoring of flood situations over large regions.
a) Optical remote sensing from geostationary platform (INSAT-3D/3DR) provides rapid and valuable information on cloud patterns and meteorological parameters (rainfall); however, unable to image the surface water conditions in presence of cloud.
b) Microwave remote sensing techniques have unique advantage in which electromagnetic radiation penetrate the clouds and senses the surface hydrological characteristics.
c)The data from SCATSAT-1 (launched by PSLV-C35 on September 26, 2016) was used for the detection of the flood situations over India. SCATSAT-1 is a continuity mission for Oceansat-2 Scatterometer for Ocean weather forecasting, cyclone detection and tracking
d) Sentinel-1A, a C-band SAR imaging satellite high resolution data on July 24, 2017 helped to compare inundated regions over parts of Gujarat.
● The National Disaster Response Force (NDRF) is a specialised force constituted “for the purpose of specialist response to a threatening disaster situation or disaster” under the Disaster Management Act, 2005
Apex Body for Disaster Management in India is the National Disaster Management Authority (NDMA). The Chairman of the NDMA is the Prime Minister
The ‘nodal Ministry’ in the central government for management of natural disasters is the Ministry of Home Affairs (MHA).
The responsibility for Disaster Management in India’s federal system is that of the State Government.
When ’calamities of severe nature’ occur, the Central Government is responsible for providing aid and assistance to the affected state, including deploying, at the State’s request, of Armed Forces, Central Paramilitary Forces, National Disaster Response Force (NDRF), and such communication, air and other assets, as are available and needed.