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Krishna Vatsa - Resilience-based approach to Flood Risk Management in South Asia
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Krishna Vatsa - Resilience-based approach to Flood Risk Management in South Asia

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Panel II: “Approaches to Infrastructure Resiliency in Different National Contexts” ...

Panel II: “Approaches to Infrastructure Resiliency in Different National Contexts”
Krishna Vatsa, Regional Disaster Risk Reduction Advisor, South Asia UN Development Programme, Bangkok, Thailand

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  • To be strengthened through the Koshi survey

Krishna Vatsa - Resilience-based approach to Flood Risk Management in South Asia Krishna Vatsa - Resilience-based approach to Flood Risk Management in South Asia Presentation Transcript

  • Krishna S. Vatsa Regional Disaster Reduction Advisor, BCPR-UNDP
  • Resilience in the Context of South Asia Floods Recent Floods in South Asia have brought the focus on “Resilience” in several ways: • Climate Change and its Impact • Disruption of natural drainage and inundation • Vulnerability of Flood Protection Structures • Transportation and Civic Amenities • Community-level Early Warning & Preparedness • Coordination of Emergency Response
  • Climate Change & its Impacts • Monsoon currents originating in the Bay of Bengal interact with the low pressure systems arising from the Arabian Sea and the Westerly disturbances from the Mediterranean • Concentrated rainfall in the river catchments, particularly in hilly areas, sometimes augmented by snowmelt flows • Breach of glacial lakes– both with stable and unstable moraine barriers, which bring down a huge amount of sediments and debris
  • Avulsion of Rivers • Rivers carry heavy sediment load, aggrading the channels, and even a small event can cause rivers to change their course • The 18 August 2008 avulsion of the Kosi River in Bihar, India– the river shifted its course by 120 km eastward causing massive floods • During 2010 floods in Pakistan, there two major river avulsions (sudden changes in flow location) occurred in the Indus river in Sindh; Part of the Indus river flowed 50–100 km west of its pre-flood location.
  • The Great Avulsion of Kosi River, 2008
  • Vast Expanse of Inundation • When the rivers take a new course, it generally has a much lower carrying capacity; water flows like a sheet, it has a width of 15 to 30 km. with a high velocity. So floods spread across thousands of square kilometers, giving it an ocean-like appearance • Indus water flooded 8,000 sq. km. of agricultural land • Kosi floods inundated 3,700 sq. km., causing millions of people to be displaced and living in camps
  • Disruption of Natural Drainage • Channels carry heavy sediment load, reducing their capacity to carry water • Indiscriminate construction and encroachment in river beds narrows the channels • Silting up of local water storages such as ponds, tanks, and destruction of wetlands, reduces the capacity for water storage • Drying up, dereliction, and encroachment of natural water channels • Non-functioning of flood regulation structures
  • Dhom FRL 747.70 / 11.70 TMC R. Krishna Satara R. Venna (Dhom to Karad :16 hrs) Kanher FRL 690.78 / 9.55 TMC(Khaner to Karad:13 hrs) (Karad to Sangli:14 hrs) Karad - CWC River Gauging station R. Koyna Karad FRL in m / Contents (TMC) Koyna FRL 657.90 / 94.57 TMC (Koyna to Karad :9 hrs) Warungi Sangli (Sangli to Rajapur w ier:7.5 hrs) R. Warna Samdoli Arjunw ad Warna FRL 626.90 / 27.50 TMC(Warna to Sangli:15.5 hrs) R. Krishna Kolhapur (Kol'pur to Kur'w ad: 8 hrs) Shirol R. Panchganga Terw ad Kurundw ad Radhanagari FRL 591.11 / 7.76 TMC R. Dudhganga Sadalga Galgali Dudhganga FRL 646.00 / 23.45 TMC R. Ghatprabha Bagalkot (Travel time show n are for free flow conditions) Almatti FRL 519.60 / 110 TMC River Length in KM Krishna up Border 301 Koyna upto Karad 119 Warna upto Haripur 104 Panchgang a upto Kurundwad 83 Dudhganga upto Yedur 69 Ghatprabha upto Mangur 59
  • Flood Early Warning Systems • Water Authorities are the designated agency for flood forecasting and early warning who maintain a network of weather stations throughout the country. • Weather stations manual, ill-maintained, inadequate, and not supported by doppler radars. Do not even cover all the flood prone rivers and drainage system. • Hydro-meteorological data recorded manually and communicated by wireless and/or telephone. Lack of Automatic Sensors and Telemetry System for data collection and dissemination • EWS not supported by any projection of inundation / submergence. A general warning regarding heavy rains does not provide indication of the extent of flooding.
  • Structural Approach to Flood Mitigation • In 1950s, the floods were sought to be controlled through construction of embankments along the rivers across the sub- continent • In India, about 34,000 km of new embankments were constructed since 1954, mostly in north-eastern states. The Government of India also constructed embankments in major river systems of Nepal.• • In Pakistan, it is about 6,800 km of embankments along Indus and other rivers in all the provinces, along with 1,410 spurs.
  • Structural Approach to Flood Mitigation • In Bangladesh, a total of 5,695 km of embankments, including 3,433 km in the coastal areas, 1695 flood control/regulating structures, and 4,310 km of drainage canals have been constructed. • Embankments have proved to be an expensive option, leading to considerable problems of sedimentation and regular maintenance. • Poor maintenance of the bunds causes breaches. Such breaches often cause great damage because of their unexpected nature and intensification of land use following the provision of flood protection.
  • Urban Flooding • Prior to urbanization, there existed a greater lag time between intense rainfall and peak stream flow. • Due to urbanization the lag time is shortened, peak flow is greatly increased, and the total runoff is compressed into a shorter time interval, creating favorable conditions for intense flooding. • For example, in a city that is totally served by storm drains, and where 60% of the land surface is covered by roads and buildings (one like Dhaka City), floods are almost six times more likely
  • Mortality and Incidence of Diseases • Though mortality related to floods decreased in the last two decades, the number of deaths increased in recent floods Floods No. of people died 2008 Koshi floods 500 2010 Pakistan floods 2,000 2013 Uttarakhand, India 6,000 • The incidence of diseases increased considerably after 2007 floods across the South Asia • Access to water and sanitation facilities in the water-logged areas very limited; The ingress of saline water in the coastal areas has decreased the availability of drinking water
  • Use of Toilet During FloodUse of Toilet (caste wise) In % Total usage: 8.9% Toilet Usage 16
  • Flood Relief and Response • Millions of displaced people occupy higher grounds without food provision or civic amenities. • As the duration of floods has generally increased, displacement is often longer, leading to disruption of employment, education, and other economic activities. • There are not enough boats, search and rescue volunteers, and other resources to help people • Relief norms are not uniform leading to uneven access to relief assistance
  • Floods: A Serious Gender Issue • Disempowering impact (Water, water everywhere, but we could not swim) • Sense of fear and acute anxiety (I was all alone with my children) • Living on Embankments and Cooking in Open (Water used to stay in the field for almost a month – to be born in the kacchar is useless) • Loss of Sanitation, Privacy, and Dignity (It is very difficult for us if we feel we have to go to the toilet during the daytime)
  • Resilience Approach to Flood Risk Management • Take river basin as a unit of mitigation planning • Suggests an approach, that allow the river its space for discharge, but aim at minimizing the flood impacts • Includes both structural and non-structural measures • Decreases the protection of natural areas, and increases the protection of cities and built space • Improve the floodplain management through changing land use • Increase community awareness and preparedness and diversify livelihood opportunities
  • Specific Elements of Floods Resilience • Reduce emphasis on embankments as a way to deal with floods; they create their own risks • Make the river beds free of encroachments • Increase plantations and forest cover in catchment areas of rivers • Improve the density of telemetric systems to improve early warning system • Elevated houses for reducing the flood impacts
  • Developing a Flood Risk Management Programme for Pakistan • Systematic Assessment of Flood Hazard Risks: preparation of simple hazard maps on the basis of occurrences of recent floods • Improvement of Flood Warning System through Installation of Automatic Weather Stations • Setting up partnerships with private sector mobile phone companies for timely and effective warning dissemination
  • Flood Risk Reduction in Pakistan • Flood Protection Measures: – Improve Conveyance and Relief Channel – Reopening culverts – Increasing the Water Storage – Studies to improve reservoir management – Small earthen flood protection structures – Provision of flood shelters – Flood-resistant houses • Advocacy of Floodplain Restoration including mapping and land use planning