Irrigation Australia / 7th Asian Regional Conference, ICID Droughts, Floods, Environment: Managing Consumptive Water Needs Sustainably Water balances between upper dam and lower estuary reservoir in South Korea – Case of Boryeong dam and Busa esturary reservoir 27 June 2012 Jaekyoung Noh, Daesik Kim, Jaenam Lee 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 ONE(One parameter New Exponential) Hydrologic Model P ETa Eta = f(e-k1 S) ETo Q S One parameter : α Q = f(e-k2 Sα) S General one parameter equation of ONE hydrologic model Daily inflows using general one parameter (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, instreamflow 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 condition Reliability 79.6 % Water balance of Busa reservoir • Inflow to Busa (QIbs) = SQ from Boryeong (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 (Boryeong) • 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 constructed. • Upper Boryeong dam had not enough capacity to supply various waters. • Water storages of lower Busa reservoir were well fitted to observed data. • Using these developed models, upper dam and lower reservoir will be able to operate effectively in high salinity period.