Flood Management and Floodplain Ecology 2nd Annual Mekong Flood Forum

Marc GoichotCoordinator

WWF Living Mekong Initiative (LMI)

Significance of the Mekong Floodplains

• Floods are a natural process that support life

• Mekong is one of the last large natural-flow rivers

(Yangtze, Red River are diked)

WWF’s Involvement with Flood Management in the Mekong

• Benefits of floods (research)• Flood mitigation dam assessments• Interaction between road and floods (policy)

Benefits of Floods

Results of 3 reports:

1) Values and functions of the floods – Economics and local perspectives (literature, workshop, field work)

2) Agricultural benefits of the floods (literature, interviews)

3) Seasonally Flooded Habitat and NTFPs– Laos (field work)

Flood Benefits

• Agricultural productivity• Freshwater ecosystem productivity (Quantitative

data showing relationship between flood levels and fish populations)

• Marine ecosystem productivity• Forest productivity• Hydrologic functions • Geomorphologic stability • Navigation• Reduced saltwater intrusion/washing• Biodiversity

Benefits to Agriculture

• Fertiliser benefit - Benefits of silt deposition to agricultural activity

• Flushing benefit - Benefits floods provide to maintaining soil quality (removing salt, pollution and/or other contaminants).

• Pesticide benefit - The floods may provide to controlling pests and diseases.

• Geomorphological stability – shape and stability of banks depend of floods

• Hydrological processes - e.g recharge aquifers.

Benefits to Agriculture

Research methodology developed to find out:

• Overall benefits and costs • The crop area likely to benefit from floods • The total economic value of benefits considered from

flooding to total economic activity• Potential losses that would be generated by modifying

flood regimes

Local Perceptions - the 3 Kinds of Flood

Impacts Flood Type

Very Large Moderate Small

Agricultural Improved fertility

Pest control

Damage to certain crops

Strains rice cultivation

Excellent fertility

Excellent rice crops

Poor fertility

Increased pests (chemicals)

Dry season rice harvest/ lotus farming impossible

Fishing Improved access

More fishing pools after flood

Inhibits migration of Pangasius fry

Poor fish yield

Intensive fishing pressure

Resettlement

/health

Resettlement needed

Drowning (child/livestock)

More water-borne disease

Comfortable living conditions

No resettlement needed

Problems of Quantification

• Benefits of floods are difficult to ascertain

• Basis to argue precautionary principle

• Recommend further study

Seasonally Flooded Habitat and NTFPs

Supporting Biodiversity and Local Livelihoods in Southern Lao PDRMain Conclusions:• Small to average size floods (<1 week in duration) are

generally seen as beneficial, particularly for improving soil fertility

• Large floods are problematic, causing transportation problems, livestock disease and loss of crops

• Seasonally flooded habitats are important areas for collecting NTFPs

• NTFPs are vitally important to poor/remote communities (up to 90% of income)

Seasonally Flooded Habitat and NTFPs

Supporting Biodiversity and Local Livelihoods in Southern Lao PDR

Specific Examples of Importance: • 40% of the NTFP’s the villagers collected were exclusively

from seasonally flooded areas

• Villagers ranked natural ponds in the floodplain as the most important aquatic habitat type, accounting for 60% of the income derived from aquatic habitats

Sustainable Management of Floods on the Huong River (Perfume River)

Central Vietnam

Cooperating with JBIC and PPC TT-H to find sustainable solution for flood management:

• Propose technical solutions to limit the impact of Ta Trach Dam flood mitigation project with focus on environmentally friendly transit of sediment through the reservoir.

• Better understanding of natural fluvial and marine dynamics to identify additional measures for flood mitigation (e.g. dredging, recreating natural delta).

Roads and Floods“Developing Economically Sound and Environment Friendly

Structural Standards for the Design of Roads in the Mekong Floodplains”

a project concept

developed by MRC and WWF

Roads and Floods“Developing Economically Sound and Biodiversity Friendly Structural Standards for the Design of Roads in the Mekong

Floodplains”

1) Roads are regularly damaged after floods

2) Roads often act as dams, increasing the level and duration of floods creating more damage to local populations

3) Roads in the floodplains affect the natural dynamics of floods and therefore impact on movement of fish and other aquatic life

Roads and Floods“Developing Economically Sound and Biodiversity Friendly Structural Standards for the Design of Roads in the Mekong

Floodplains”

Objectives:

1) Make future structures more resistant to floods

2) Reduce their negative impacts on the agricultural and fisheries productivity of floodplains, biodiversity and river morphology.

Benefits to both financial investment in development and biodiversity conservation

Project Structure - Tasks

The main tasks to be carried out are:

1. Undertake a literature search and conduct field tests over four flood cycles to provide a more up-to-date scientific and engineering basis for structural-development standards

2. Translate the technical findings into policy recommendations

Project Structure – Tasks (cont.)

3. Ensure policy recommendations are understood and used by decision makers in ministries of riparian countries* and development banks

4. Ensure that lessons learnt from application of the standards in future road construction and rehabilitation projects are monitored to continue to improve the standards *

* To be conducted through the NMCs and the Flood Center (Component 1 of the FMMP)

Next Steps

• Benefits of floods – Literature on benefits of floods is poor : needs more research– Establishing Local Dialogue (Dialogue on Water, Food and the Environment)

• Discussing values of flood and importance to fisheries• Set recommendations for more research• How to translate research results into policy

• Relate findings in Huong River to other rivers

• Address the issue of road rehabilitation/construction in the floodplains (most rehabilitation projects are being conducted without EIA’s) – Contribute to developing standards for building roads adapted to Mekong

specificities– Built capacity to monitor and improve standards