Dams and Levees as Climate Change Maladaptation

Patrick McCully“Rivers for Life 3”Temacapaulín, Jalisco, MexicoOctober 2010

Key Messages

• Rapid rise in flood disasters

• “Hard path” flood control often counterproductive under existing climate, will become more dangerous under rapidly changing climate

• Adapting to flood impacts of climate change requires “soft path” flood risk management

Rapid Increase in Flood Disasters

Floods are most destructive, most frequent, most costly natural disasters on earth

• Frequency and severity increasing, will continue doing so

• Number of people living in path of potentially damaging flood by 2050 = 2 billion (1bn in 2007)

In 2007 . . .

• Africa’s biggest floods in 30 years (23 countries)

• South Asia: 41m people affected

• “Hundreds of thousands” offamilies displaced in China

• Homes of nearly 1m people damaged in Tabasco

• $9bn damages in England

Why the Rise in Flood Disasters?

• More people, infrastructure in harm’s way

• Watersheds, rivers, floodplains degraded, mismanaged

• Intense rain events more frequent, severe

• Flood control approaches counter-productive, especially in rapidly changing social and climatic contexts

“Controlling” Floods, Worsening Floods

• Dams and levees have prevented countless potential floods (at great ecological cost)

• Dams and levees have created countless floods and magnified the severity of floods

• Dams and levees have disadvantage of discontinuity: time from “safe” to “failure” very short so little time for warning and evacuation

• Dams fail, are poorly operated, and have permanently flooded an area the size of California

“Flood Control” is Not Working

• Switzerland: flood losses x4 since 1970 despite major increase in flood control investments

• India: 17,000 km levees since 1954. At best no decrease in area affected; increases in deaths and people affected.

• Bihar: levee length x22, flood-prone area tripled

“Flood Control” is Not Working

• Switzerland: flood losses x4 since 1970 despite major increase in flood control investments

• India: 17,000 km levees since 1954. At best no decrease in area affected; increases in deaths and people affected.

• Bihar: levee length x22, flood-prone area tripled

Multipurpose Dams: A Deadly Conflict of Interest

Pakistan 1992: 500 killed below Mangla Dam

Nigeria 1999: 1,000 killed, 300,000 harmed by releases from Kainji, Jebba and Shiroro dams

Nigeria 2001: 200 killed, 82,000 harmed by releases from Tiga and Challawa dams

India 2005: 62 killed by releases from Indira Sagar Dam

India 2006: 39 killed by releases from Manikheda Dam;120 killed, $49bn losses by releases from Ukai Dam

Climate Change and Dam Safety• Dams (and levees) designed for a static climate

• Poor maintenance of aging dams a growing problem. Global under-investment in dam safety: $300bn?

• None of world’s 54,000 large dams built to withstand changing hydrology

• Dam lifespan reduced by increased sedimentation

"Dams are loaded weapons aimed down rivers.” - Jacques Leslie, author of Deep Water

• Climate change is happening

• We need to adapt (and MITIGATE)

• Poor, already most vulnerable, also most vulnerable to greenhouse-world disasters

• Oxfam: developing countries will require $50bn/yr + emergency relief funds (humanitarian funding 2005 $8.4bn)

We Must Adapt

• Climate change is happening

• We need to adapt (and MITIGATE)

• Poor, already most vulnerable, also most vulnerable to greenhouse-world disasters

• Oxfam: developing countries will require $50bn/yr + emergency relief funds (humanitarian funding 2005 $8.4bn)

We Must Adapt

Flood Risk Management = Climate Adaptation

• Move from static flood control to flexible, adaptive flood risk management

• FRM means cost-effective, no regrets measures

• FRM assumes floods will happen, aims to reduce damage

• FRM understands floods are ecologically essential

“Soft Path” Flood Risk Management

• Improve disaster-preparedness, flood warning systems, flood recovery planning

• Remove/move back levees; remove ineffective and dangerous dams

• Where possible, move development out of floodplain

• Only build levees where essential, spend more on levee maintenance

• Improve dam management, force compliance with strict operating rules

• Dam safety evaluations and investments

• Flood-proof buildings

• De-pave cities, capture rainwater

FRM is Ecological Adaptation

• Restoring wetlands & rivers will help slow floods, absorb water

• Removing structures that fragment, dewater, simplify river ecosystems will improve their resilience to a changing climate

Climate Change Adaptation = Design for Graceful Failures

Need “to plan how to respond before, during and after all floods rather than simply construct an engineering solution that protects up to some design standard flood . . . We should seek forgiving systems those that fail gracefully.”

Colin Green, Flood Hazard Research Center, University of Middlesex

FRM: Examples

• Community-based flood forecasting: 1,000 people in Ganga-Brahmaputra-Meghna basin form early warning network using phones and email.

• Loire Grandeur Nature Plan: Government dropped planned flood control dam and adopted community designed FRM approach. Flood strategy now part of basin-wide govt., landowner, NGO ecological restoration and management plan.

• Giving more room to the Rhine: 20-Year Action Plan on Flood Defense adopted by 5 countries. Includes levee removal, river restoration, improved flood warning and evacuation.

• Yangtze wetlands restoration: WWF-Beijing and local govts. plan to restore 20,000 km2 wetlands along middle Yangtze.

Thank You!