mk2 quantifying water user trade offs at yali reservoir vietnam
TRANSCRIPT
QUANTIFYING WATER USER TRADE OFFS AT YALIRESERVOIRBamboo Green Hotel Da Nang, 17th Sept 2013
Nguyen Viet Anh, Tarek Ketelsen, Mai Ky Vinh
MK2: Valuing Multiple uses of reservoir waters: WorldFish – ICEM –IFPRI – CIEM – DLOF - CEPA
Contents
Characteristics of water use
demand
Hydrological Characteristics
Cost and benefit evaluations
between water users
• CIEM carried out the survey within 2km buffer of Yalireservoir
• Surface water availability
• Reservoir water allocation & flows
• Storage capacity and hydro-electricity production
• Economic costs & benefits
• Social costs and benefits
• Conclusion
Research scope• Water shortage occurs in Yali catchment during the dry
season which is affecting agriculture and aquaculture production which are important for the provincial economy
• Yali reservoir has capacity to provide dry season supply, but has not been utilized by provincial users because it was built for electricity production
• There is a perceived water conflict between electricity production and consumptive use by surrounding communities
• The study investigates how significant is this conflict? What is the trade off in electricity production if some reservoir waters are used for community abstraction?
Water consumption
ItemWater Demand (m3/year)
81,328,065
1. Domestic use 937,090
2. Agriculture 76,597,400
Rice 22,160,922
Corn 372,918
Casava 480,971
Tea 10,876,500
Coffee 24,478,816
Sugar cain 17,588,870
Rubber 638,402
3. Aquaculture 360,000
4. Livestock 3,433,575
Cattle 1,209,642
Pig 423,206
Poultry 1,800,727
Overview of the methodology
_
Water availability
Water demand
Water availability
with consumptive
use
Identify critical areas
Rainfall
Inflow
Water demand
Evaporation
_
+ _ OutflowPower
Production
Surface water availability: Moisture budget without consumptive use
Surface water availability: with consumptive use
Water availability in the dry season
Surface water availability• Water availability stays in
surplus during the wet season and mostly in deficit during the dry season
• Surface water stress occurs around Yali reservoir catchment during the dry season (over 300mm deficit)
• Small contribution of water from the reservoir could be used for irrigation within 2km buffer area
• What would be the impact on power production?
Hydrological Model• Using MODSIM hydrological
model which is developed by Colorado State University
• The model was constructed using the following data:– Daily nature inflow to the
reservoir (VMOD)
– Daily precipitation and evaporation
– Water demand
– Storage capacity and power generation (CSUPD)
Evaporation
Precipitation
Scenario 1 - Baseline
• Reservoir is managed exclusively for hydropower production
– On average, the reservoir is full for 78 days over a year (21%)
– Average annual power generated is 3,595 GWh
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
18,000
20,000
0
100,000
200,000
300,000
400,000
500,000
600,000
700,000
800,000
900,000
1,000,000
Jan-01 Jan-02 Jan-03 Jan-04 Jan-05
Ene
rgy
(KW
h)
Live
Sto
rage
Cap
acit
y (1
00
0 m
3)
Reservoir storage Power generation
Scenario 2• Reservoir water is used to
meet 100% of the total water demand by agriculture, domestic and aquaculture uses within a 2km buffer zone around the reservoir
• Annual water demand is 81,328,065m3
0
1000000
2000000
3000000
4000000
5000000
6000000
7000000
8000000
9000000
10000000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Wat
er
de
man
d (
m3
)
-20%
-18%
-16%
-14%
-12%
-10%
-8%
-6%
-4%
-2%
0%
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Ch
ange
Reservoir storage Power generation
Scenario 2 compared to Baseline
Wet season
Scenario 2 findings• Annual storage capacity and
power production are expected to reduce by 0.7% and 1% respectively
• Storage capacity in the dry season is reduced by 3.6% (493m3
daily)• Power production in the dry
season is reduced by 3.5% (3,194kWh)
• Annual economical cost from power generation reduction is 462,000USD of which 83% of the loss occurs during the dry season
• However most of electricity is generated during the wet season. Dry season production is only 22% of the yearly production
-4.0%
-3.5%
-3.0%
-2.5%
-2.0%
-1.5%
-1.0%
-0.5%
0.0%
Annually Dry season Wet season
Ch
ange
(%
)Storage capacity Power generation
Conclusions of the water availability assessment
• Relatively small change for hydro power production (i.e. 1% energy reduction annually) can have big impact on communities surrounding Yali reservoir (within 2km). Especially in the dry season, when there is water stress and higher dependency on groundwater.
• 462,000USD loss from electricity production could bring greater benefit for surrounding community
Thank you!