Environmental Flow- An Interdisciplinary Approach To ...

Regional Water & Wetlands ProgramAsia Regional Office

Environmental Flow- An Interdisciplinary ApproachTo Facilitate Negotiations on Sharing Water in The Mekong Region : Lower Songkhram River Basin Case Study


--Strongly seasonal Strongly seasonal variation in flowsvariation in flows 1% of maximum floodmaximum flood

- Flows through parts Flows through parts of 4 Provincesof 4 Provinces

-- Largest Largest floodpainfloodpain800800--1850 km21850 km2

-- Unique flood plain Unique flood plain ecosystem as ecosystem as TonleTonleSap systemSap system

-- Wetland site ofWetland site ofinternational international importance (OEPP, importance (OEPP, 1999).1999).

Lower Lower SongkhramSongkhram RiverRiver BasinBasin


Lower Songkhram Ecosystem of the Lower Songkhram River Basin

Dry Season

Wet season


Ecosystems & biodiversity Significance of the Ecosystems & biodiversity Significance of the

SongSongkhkhram Basinram Basin

• High degree of habitat diversity ( river channels, marshes, pools, streams, ox-bow lakes and various artificial water bodies.)

• Paddy fields, broad seasonally inundated grasslands. Aquatic biodiversity (183 species of fish have been recorded). endangered” Giant Mekong Catfish

• 102 species of bird have been recorded during limited studies in the Lower Songkhram Basin.

• 191 of Vegetation, 17 Fungai harvested local villager-centered participatory research (Tai Baan Research) which can help inform the E-Flows approach


Main threats to the Main threats to the SongkhramSongkhram RiverRiver

• Large-scale water infrastructure developments

• Inappropriate and poorly planned infrastructure built on floodplain

• Sensitive seasonally flooded forest degradation and conversion to agriculture

• Expansion of monocrop industrial tree plantations (e.g. eucalyptus and para rubber ) in flood plain

• Expansion of salt, potash or other mineral extraction activities which can cause negative impacts for soil and water resources


Main threats to the Main threats to the SongkhramSongkhram RiverRiver

• The introduction and spread of invasive alien species (IAS), such as catclawmimosa (Mimosa pigra), Nile tilapia (Oreochromis nilotica), and the golden apple snail (Pomacea canaliculata).

• In-basin population growth and urbanisation leading to increasing conflicts over water resources (quantity and quality) which are not being adequately addressed at present.

• Changes in water flows, sediment and nutrient levels of the Mekong mainstream as a result of upstream infrastructure development may affect the annual flood regime and fish migration pattern in the lower Songkhram Basin


Why might an E-Flows approach be important to Songkhram Basin planning processes?

• E-Flows approach helps contribute towards IWRM

•General trend towards decentralisation and greater local participation in planning and decision making. River Basin Committee (RBC)

• Adopt a whole basin approach to water resources management,

•The holistic perspective of an E-Flows approach can help in determining environmental flow requirements,

• Tools and techniques from reconnaissance level hydrology-based studies to intermediate or comprehensive assessments which take into account biophysical, sociological and economic consequences of a range of management scenarios and flow regimes.

• Ensures that a wide range of voices are heard, from the state and non-state sectors, through wide information scoping and use of multi-stakeholder platforms.


SongkhramSongkhram EE--Flows study Flows study –– research research methodology and approachmethodology and approach

• Series of consultations with Site partners and various other stakeholders in the Songkhram Basin

• Agree Conceptual approach to understanding biophysical and socio-economic dimensions of the river system

• A multi-disciplinary team have been established of Thai professionals to work in the field together, with supported by international expert in E-Flows ( IWMI )to research the state of knowledge about the wider river system and exchange their knowledge and experience about key areas related to flows and flow dependence by local communities.

• Team conducted two field visit in the 2006 rainy season and conducted a second field visit during the 2007 dry season, comparing the study sites at the two extremes of flow.

•Shared the results at a Development Scenarios Workshop to be held in April 2007, invited a variety of stakeholders participate and increase awareness of the importance of environmental flows.

• E-Flows study and workshop will inform basin stakeholders of the study results and contribute towards the compilation of an E-flows manual for the SongkhramRiver Basin, to help guide future planning and decision making.


Key FindingsKey Findings

The importance The importance of the flood of the flood

pulse for pulse for People and People and

Nature in the Nature in the SongkhramSongkhramRiver BasinRiver Basin


Importance of floodpulseImportance of floodpulse-- rich fisheries in the floodplain arearich fisheries in the floodplain area

The high productivity of the floodplains and rich fisheries in tThe high productivity of the floodplains and rich fisheries in the Nam he Nam Songkhram floodplain is based on the flood pulseSongkhram floodplain is based on the flood pulse

11

‘‘Flood pulseFlood pulse’’Ecosystems that experience fluctuations between Ecosystems that experience fluctuations between terrestrial and aquatic conditions are called pulsing terrestrial and aquatic conditions are called pulsing ecosystems, and fall within the domain of the flood ecosystems, and fall within the domain of the flood pulse concept pulse concept (Junk, 1997).(Junk, 1997).

The flood pulse is essential The flood pulse is essential to sustain the flood plain to sustain the flood plain ecosystem system and ecosystem system and fishery in the Songkhram fishery in the Songkhram


Water level in the floodplain controlled by Water level in the floodplain controlled by the water level in Mekong mainstreamthe water level in Mekong mainstream

•• The water level in the floodplain is controlled by the water levThe water level in the floodplain is controlled by the water level in the el in the Mekong mainstream Mekong mainstream

•• Water level in the Mekong mainstream is very similar to the wateWater level in the Mekong mainstream is very similar to the water level in r level in the floodplain as illustratedthe floodplain as illustrated

the upstream flood protection is does not have any impact on flothe upstream flood protection is does not have any impact on flood in the od in the

floodplainfloodplain

TS Point3Mekong mainstream


Land UseLand Use

Rapid Land conversion from upland crops such as Rapid Land conversion from upland crops such as sugarcane and cassava to sugarcane and cassava to parapara--rubber and eucalyptus rubber and eucalyptus between 2000 between 2000 -- 2006.2006.Rapid conversion of bamboo forest to dry season rice in Rapid conversion of bamboo forest to dry season rice in the floodplain area the floodplain area Upstream infrastructure development and clearing of the Upstream infrastructure development and clearing of the natural vegetation on the river banks and flood plain has natural vegetation on the river banks and flood plain has resulted in banks destabilization, soil erosion and river resulted in banks destabilization, soil erosion and river shallowingshallowing/widening observed in the Nam /widening observed in the Nam OunOun..Lower soil fertility (nutrients, sediments) in upper than Lower soil fertility (nutrients, sediments) in upper than lower lower SongkhramSongkhram River due to River due to SongkhramSongkhram floods and floods and Mekong backwater effectMekong backwater effect


Flood pulse importance for vegetationFlood pulse importance for vegetation

Flood plays an important role in seed dispersal and germination Flood plays an important role in seed dispersal and germination

The downstream flow important to distribute fruits or seeds for The downstream flow important to distribute fruits or seeds for germination for the dry season.germination for the dry season.

Without regular overtopping floodplain floods each year, marginaWithout regular overtopping floodplain floods each year, marginal l plants will become the dominant plant group due to progressive plants will become the dominant plant group due to progressive shallowingshallowing of backwater features. The water area would be reduced, of backwater features. The water area would be reduced, then the then the strongly embraceable shrub community strongly embraceable shrub community will gradually will gradually occupy the margins. occupy the margins.

Flood plain vegetation used for fuel, agricultural tools, house Flood plain vegetation used for fuel, agricultural tools, house construction, weaving, material dyes, fishing gear, fodder for construction, weaving, material dyes, fishing gear, fodder for livestock, medicine, spiritual/religious ceremonies and livestock, medicine, spiritual/religious ceremonies and threbythreby, , contributes to local peoplecontributes to local people’’s livelihoods for food and income.s livelihoods for food and income.


พื้นที่ปา ปาไผ นาขาว พื้นที่ปาบนที่ดอน

ไมพุมชายปา

ที่ลุม ปาบุงริมน้ํา นาแซง ปาบุง

ริมน้ําแมน้ํา

ภาพวาดลักษณะพื้นที่ริมแมน้ํา (ดัดแปลงจาก Mun River Floodplain Project)


VegetationVegetation

Several floodplain vegetation species have been Several floodplain vegetation species have been replaced by extensive stands of replaced by extensive stands of PaiPai KasaKasa, , which iswhich is a a successful pioneer species on disturbed flooded land,successful pioneer species on disturbed flooded land,PaiPai KasaKasa has become the dominant overhas become the dominant over--story story vegetation species across many areas.vegetation species across many areas.


SocialSocial

• Land rights of the flood land is unclear, resulting riparian resources in jeopardy.

• Increase of consumerism drives people to increase derivation of benefits from floodplain resource more than before. This include expanding of agricultural land.

• The convincing price of eucalyptus drives people to clear floodplain forest to grow eucalyptus

• Increase migration has not resulted in less pressure on floodplain resources.

• The role of ago business in floodplain could intensify erosion of floodplain resources


Fish/ปลา

Fishers&Villagers/ชาวบานผูใชประโยชน

Habitat/แหลงที่อยูอาศัย

ประมงในระบบแมน้ํา-พืน้ที่น้าํทวม (River-Floodplain Fisheries)

• ความหลากหลายของประชากรปลาสูง: 43 ชนิด จาก 33 ครอบครัว High diversity of fish fauna (143 species of 33 Families from E-Flow survey and 193 from species list of fish fauna in the Songkhram,DOF)

• การบริโภคสัตวน้าํ ประเมิน 50.3 กก./คน/ป หรือ 249 กก./ครัวเรือน/ป Household consumption was around 50.3 kg/person/year, or about 249 kg/HH/year (AMCF, 2007)

• ผลจับสัตวน้ํา 207 กก./ครัวเรือน/ป และทําประมง เฉลี่ย 127 วัน/ป Household catch production was around 207 kg/HH/year on average for 127 days/year

• แหลงที่อยูอาศัยสัตวน้าํ แมน้ํา/ลําหวย, พื้นที ่ น้ําทวม (ปาบุง-ปาทาม), นาในที่ลุม River/stream, Inundated flooded (flooded forest and flood glassland included lowland paddy field)

ประเมินผลผลติปลาธรรมชาติ ของระบบแมน้ําสงคราม อาจ สูงกวา 20,000 ตนั/ปCatch yield could be more than 20,000 tones/year


ประมงในระบบแมน้ํา-พืน้ที่น้าํทวม (River-Floodplain Fisheries)

การอพยพเพื่อสบืพันธุในลําน้ําและพื้นที่น้ําทวมReproduction movement to Spawning ground River/stream

Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec. Jan. Feb. Mar.การอพยพสัตวน้ํา/ ปลาFish stock movement

วงจรน้ําขึน้-ลง Flood Cycle

Fish Life-cycle

วงจรการทําประมงFishing cycle

การกระจายตัวออนในลําน้ํา/พื้นที่น้ําทวม Larvae drift And Juvenile movement

อพยพจากพื้นที่น้ําทวมYoung fish Leave floodplain

ปลาเล็ก/ใหญ หาที่หลบซอนในฤดูแลงSub-adult and adult fishNurse and feeding in a dry refugeseason area maintain stock for next flood cycle

Migration for spawning along the River/stream and floodplain

Trophic feed & grow out in floodplain

Migrated out floodplain

Dry refuge season

เมย. พค. มิย. กค. สค. กย. ตค. พย. ธค.

มค. กพ. มีค.

ชวงทําประมงปลารุนในพื้นที่น้ําทวม/อพยพกลับ Peak catch of young fish in flooded area downstream migrated back the river

ทําประมงในแหลงที่หลบอาศัยในฤดูแลงCatch in dry refureseason area; river/stream,backswamp, reservoir

ทําประมงปลาใหญที่อพยพมาวางไขCatch fish migratedfor spawning


In Summary In Summary The upstream flood protection do not have impact on flood The upstream flood protection do not have impact on flood

in the floodplain as the water level there is fully controlled bin the floodplain as the water level there is fully controlled by y the water level in the Mekong mainstreamthe water level in the Mekong mainstream

The flood pulse (terrestrial and aquatic phases)The flood pulse (terrestrial and aquatic phases) of the of the SongkhramSongkhram River sustains The flood plainRiver sustains The flood plain-- Ecosystem and Ecosystem and Fishery for People and NatureFishery for People and Nature

The result have already addressed in the wetland policy The result have already addressed in the wetland policy issues include 4 provinces , local authorizes , NGOs agree issues include 4 provinces , local authorizes , NGOs agree to setup the appropriate planning for improved ,sustainable to setup the appropriate planning for improved ,sustainable practices plus the copractices plus the co--management management

Environmental Flow- An Interdisciplinary Approach To ...

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