| OCR Text |
Show The procedure then initiates for each reservoir s, with no evaporation considered at iteration j= l. A storage capacity SJS is determined for this condition and then the simulation over the operation period repeated, using evaporation values based on monthly areas AJst computed using this storage capacity. The process is repeated with new values of SJS after each iteration, until an iteration limit is reached or the convergence criteria specified by equation ( 5.6) are satisfied. ( 1) QRa < QIa for each time period t ; S^ O K' Si' 1! ( 5.6) ( 2) --$- £ tolerance si- 1 The first condition represents a situation where the demands do not exceed supply at any time, implying no need for active storage in the reservoir. The second condition specifies that if the absolute value of the percentage change for the required storage between successive iterations is less than a specified tolerance the scheme has converged. Experience with Bear River data indicates that for 432 month operation, the scheme usually converges to a tolerance of 0.000001 in 2 to 8 iterations, for each reservoir. The total storage Ts required at reservoir site s is then determined as Ts = max { SVJ ( 5.7) Equation ( 5.7) above recognizes that the flood storage provided may be used for storing water for other uses outside the flood season. The total storage capacity required is thus not a simple sum of the dead, active and flood storages. The spill REst or excess release from reservoir may also computed on the convergence of the MSP procedure as : REst = 0 ifSs t £ Ss REst = max ( QIst - QRst - Sst + Sst_ i, 0.) otherwise ( 5.8) 5.3.2 Determination of Optimal Hydropower plant Size The optimal Hydropower plant size Gs in MW, is determined by first computing the total possible release HTst possible through the hydropower plant at site s in month t ( eqn. 5.9), and then the corresponding possible power production Pst ( eqn. 5.10). The total release HTst is defined as the sum of the firm release for hydropower, any possible release of M& I and irrigation releases through the hydropower plant, and any available surplus releases that can be routed through the hydropower plant. M R I R HTrt . a H + dl Y , Y , b f p'M* + d2 Y , Y c. qf. + REc, ( 5.9) st st s % JLmU£ mJ tmr t sm % jL* dIBmd nn t si st v ' 108 |
