Understanding water benefit trade-offs in the Lower Mekong Basinexample from a hydropower reservoir in

Vietnam

Presentation for the 7th Annual ESP Conference8-12 September 2014, San Jose, Costa Rica

By Yumiko Kura, WorldFish – Greater Mekong Region

on behalf of: Vũ Xuân Nguyệt Hồng, Benoit Laplante, Tarek Ketelsen, Hồ Công Hòa, and Nguyễn Việt Anh

OUTLINE

1. Study area

2. Study approach and methods

3. Results of households survey

4. Results of scenario analysis

5. Conclusions

STUDY AREA

Yali Hydropower Dam became fully operational in 2002

Resettlement of 12 villages, 8,475 people between 1994 – 2001

Reservoir exclusively managed for hydropower generation

Ambitious growth targets for two provinces

1 in 100 year scale water shortages experienced in 2010-2011 dry season

STUDY APPROACH AND METHODS

Purpose: Illustrate future potential for multiple uses of Yali reservoir water

and highlight the need for coordination of water management strategies in Kon Tum and Gia Lai provinces.

Methodology:• Assessment of water uses and benefits for local communities

based on a survey of 350 households living near the reservoir• Future water demand estimates based on socioeconomic

development plans at district and provincial levels• Scenario analysis of water availability and allocation trade-offs

using hydrological models

RESEARCH QUESTIONS

What are the main sources of water that support the livelihoods of the households in the villages around the reservoir and how much do different sources of water contribute to the villagers’ economic activities?

What would be the trade-offs between single use and multiple uses of reservoir water, taking into consideration the seasonal differences in water availability and demand?

ANNUAL INCOME PORTFOLIO OF SURVEYED COMMUNITIES

Economic activity

Average household income / year(n = 350)

1000 VND USD % of Total

1. Agriculture 48246.4 2,412 79.2%Of which, Farming 42904.0 2,145 70.1% Livestock 2999.4 150 4.8%

Fishery 795.7 39.8 1.3% Forestry 1635.6 81.8 3.0%2. Non-agriculture 12730.4 636.5 20.8%3. Total 61,204 3,060.2 100%

• Largest contribution to household income comes from production of industrial cash crops—coffee, rubber, cinnamon, cassava

• Other food crops – incl. rice, maize, and vegetables, are grown primarily for home consumption

• Coffee is 100% irrigated, rice is 53% irrigated

WATER SOURCES USED BY SURVEYED HOUSEHOLDS (%)

• Public and private wells are the most importance source of water for domestic uses and livestock

• Small rivers/streams, springs, public wells are the main water source for crop irrigation

• Use of Yali reservoir water is limited to fishing and irrigation activities• Use of Yali reservoir for non-hydropower purposes is only tolerated,

not officially permitted

Water Uses River/StreamRain Water

/SpringsTap Water Wells

Yali Reservoir

Drinking 10 1 6 80 0

Bathing 9 6 5 78 1

Washing 9 6 5 76 0

Irrigation (incl. river bank garden)

36 30 6 22 4

Fishing 0 n/a n/a n/a 9

Livestock watering 8 0 0 50 0

Transportation 0 n/a n/a 0

WATER BENEFITS BY USE AND USERImportance of water resource dependent activities  

Local communities (based on household survey)Yali hydropower company (based on

secondary data)

Water Use% of surveyed HH engaged in the activity

Production output$/HH/year (for HHs engaged in the activity)

Production output per water use ($/M3)

% kept for home consumption

Value of food crop kept for home consumption ($/HH/year)

Total hydropower output to the company ($/year)

Hydropower output per water used ($/M3)

Fisheries 12.6

1,289  n/a 29 374    

Agriculture 81.3

4,273 0.276 5.39 230    

Domestic use (drinking, washing)

100   0.414        

Hydropower           47,292,000 0.007

Aquaculture 1.4 n/a 0.781        

• From Water productivity perspective, economic benefit per M3 of water derived by hydropower company is far below the benefits the local communities derive from water for any single activity

• The amount of the water that is required to generate the hydropower outputs is 7.2 billion M3/year

MULTIPLE WATER USE SCENARIOS FOR YALI RESERVOIR

Scenario 1 (baseline) – Single use: Reservoir is managed exclusively for hydropower production.

Scenario 2 – Multiple-use (rural): Reservoir water is used to meet 100% of the total water demand by the local communities within a 2km buffer zone around the reservoir (annual water demand is 81.3 million m3).

Scenario 3 – Multiple-use (urban and rural): Scenario 2 plus the water demand of provincial capital Kon Tum City in 2010 (Scenario 3a) and in 2030 (Scenario 3b), water demand of 165 million m3 and 174.7 million m3, respectively.

SCENARIO RESULTS

Scenario 2: hydropower production in dry season is reduced by 3.5% on average compared to the baseline, representing a loss of approximately US$450,000 in energy production.

Scenario 3: the loss is approximately US$1 million.

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

-8.0%

-7.0%

-6.0%

-5.0%

-4.0%

-3.0%

-2.0%

-1.0%

0.0%

Power generation Reservoir storage

Dif

fere

nce

(%)

Difference in Reservoir Storage and Energy Production Between Scenario 1 and Scenario 2

CONCLUSIONS

Increased access to the water resources in Yali Reservoir can potentially create higher economic benefits to local communities, especially in water shortage conditions, at little cost to hydropower production

The commonly held notion that hydropower is the best way to maximize the economic benefits of water, and that hydropower needs to be prioritized as an exclusive water user, is a misconception in this context

More research is needed to address several information gaps before any actual decisions on reservoir water management are made:• Technical feasibility and cost of using and distributing the Yali

Reservoir water for non-hydropower uses• Better understanding of groundwater availability, recharge rates,

and withdrawal potential to meet future demands• Most appropriate ways to maximize the benefit of additional water

for the local communities

FOR MORE INFORMATION…http://wle-mekong.cgiar.org/about/cpwf-in-the-mekong/