Water balances between upper dam and lower estuary reservoir in South Korea

– Case of Boryeong dam and Busa esturary reservoir

Jaekyoung Noh, Daesik Kim, Jaenam Lee

Irrigation Australia / 7th Asian Regional Conference, ICIDDroughts, Floods, Environment: Managing Consumptive Water Needs Sus-tainably

27 June 2012

Dept. of Agricultural and Rural Engineering, Chungnam National University

Background and objective

• High salinity of the Busa estuary reservoir in Korea, from which are being irrigated to upper paddy fields in transplanting period.

• Inflow to Busa reservoir are restricted to outflows from upper Boryeong dam.

• To develop models for water balances of Boryeong dam and Busa estuary reservoir, from which will be used to plan counter measures on high salinity in Busa reservoir.

Sites

Land uses

DEMs

Area capacity curves

Boryeong multipurpose dam on 18:30 14 June 2012

Busa estuary reservoir on 15:40 14 June 2012

Meteorological Data

Rainfalls (1973-2011)

Weirs for irrigation and thermal power plant

Weirs for suppling water to thermal power plant

Boryeong power plant

Seocheon power plant

Salinity (ppm)

Year 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

April 4,300 100 400 1,200 800 1,200 1,500 2,100 1,400 4,800

May 790 150 550 850 1,000 1,500 1,800 2,400 1,400 1,900

2009

2010

2011

Water levels in Busa

Inflows

DAWAST model (Noh, 1991)

TPHM model (Kim, 2002)

Parameter: UMAX, LMAX, FC, CP, CE

Parameter: Smax, α

S

Q

ETa

P

Q = f(e-k2 Sα) S

Eta = f(e-k1 S) ETo

One parameter : α

ONE(One parameter New Exponential) Hydrologic Model

General one parameter equation of ONE hydrologic model

Daily inflows using general one pa-rameter (Daecheong dam, 1981-2001)

One year (Daecheong dam, 1998)

Comparison of dekadal inflows (Daecheong dam, 1981-2001)

Water balance in Boryeong dam

• S(i) = S(i-1) + Q(i) – EW(i) – SQ(i)• SQ(i) = DW(i) + IW(i)+ AW(i) + MW(i)

– S: water storage– O: inflow– SQ: water supply– EW: evaporation in water surface– DW: domestic water– IW: industrial water– AW: agricultural water– MW: instreamflow

• OV(i) = S(i) – FS, if H(i)>FH– OV: overflow– FS: full water storage– FH: full water level

Daily operation result of Boryeong dam

Daily inflow to Boryeong dam (1998-2011)

Comparison of daily inflows

Comparison of dekadal inflows to Boryeong dam (1998-2011)

Domestic water 200,000 m3/d, paddy field area 1039.5 ha, industrial water 15000 m3/d, instream-

flow 0.38 m3/s

Daily irrigation water (1966-2011) from Boryeong dam

Domestic water 200,000 m3/d, paddy field area 1,039.5 ha, industrial water 15,000

m3/d, instreamflow 0.38 m3/s

Reliability 95.6%

Domestic water 226,100 m3/d, paddy field area 1,039.5 ha, industrial water 79,100

m3/d, instreamflow 0.38 m3/s – present con-dition

Reliability 79.6 %

Water balance of Busa reservoir

• Inflow to Busa (QIbs) = SQ from Bo-ryeong (SQbr)+ QI from lateral

• SQ from Boryeong = IW + AW + MW + FW + OV

• QI from lateral = Q – IW + DWr – AWbr + AWrbr + AWrbs

• IW = IWsh (Seohae) + IWbr (Bo-ryeong)

• S(i) = S(i-1) + QIbs(i) + SQbr(i) – SQbs(i) - EWbs(i) – GW(i) – AWbs(i) – AWnp(i)

• SQbs = 1000×(-385.2 + 3527.9 (h + 1.5)) – h: water level of

Busa (EL.m)

Water level to outflow of Busa

Dropped water level to Outflow from Busa

Water levels in Busa reservoir

Inflow to Busa reservoir- Outflow from Boryeong dam

Lateral inflow

Inflow to Busa

Comparison of irrigated waters from Busa

Daily simulated water storages in Busa (2009-2011)

Case of 2011

Long term simulation in Busa- inflow (1966-2011)

Inflow (1998-2011)

Water storages (1998-2011)

Salinity to inflow

Inflows during salinity data period

Comparison of salinities in Busa

Water storages during salinity data period

Water storage to salinity

Conclusion

• Water balance models were con-structed.

• Upper Boryeong dam had not enough capacity to supply various waters.

• Water storages of lower Busa reser-voir were well fitted to observed data.

• Using these developed models, up-per dam and lower reservoir will be able to operate effectively in high salinity period.