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<br />w
<br />N
<br />N
<br />(.)1
<br />
<br />EOUCll ion 9
<br />dddlnp xtsp with
<br />for X~ anc.fcalled
<br /><
<br />
<br />15 also modified by
<br />the same coefficient values
<br />(9').
<br />
<br />Two additional constraints have the form
<br />
<br />H
<br />[<jls S S
<br />1=1 i Xi,SP '" WA,sp
<br />
<br />(14)+
<br />
<br />8=1, . . ., 8
<br />
<br />s
<br />where WA,SP is the water consumptive use by
<br />crops grown under a sprinkler system. Water
<br />return flow resulting with sprinkler systems
<br />plus the definition of water consumptive use
<br />gives
<br />
<br />( S S s
<br />1 - C(sp)loJo,sp - WRF ,sp
<br />
<br />o
<br />
<br />(15)+
<br />
<br />S S s
<br />asp WO,sp - WA,sp
<br />
<br />. 0
<br />
<br />where the symbol ex gp represents
<br />irrigation efficiency of the
<br />system.
<br />
<br />the overall
<br />sprinkler
<br />
<br />Some water will be lost in desalting
<br />plants and evaporation ponds. I f We repre-
<br />sents the amount of water loss per ton of
<br />salt removed, the total amount of water loss
<br />per projected construction is WeC. The
<br />flow-balance Equation l7, the states' water
<br />allotment Equation 18, and the salt-balance
<br />Equation 20 can be rewritten as:
<br />
<br />WS + WS + WS GS + Fs,s+l _
<br />A,SP E G
<br />
<br />8
<br />"
<br />u=l
<br />u>s
<br />
<br />FU,s _ WS _
<br />RF
<br />
<br />~oJS '" WS
<br />RF ,SP 0
<br />
<br />(17) ,
<br />
<br />S S S
<br />" (WA + WA sp) + " WE +
<br />sey , sey
<br />
<br />I: WS GS ::: WY
<br />G
<br />S8y
<br />
<br />y=l, 2, . . .. 3
<br />
<br />(18) ,
<br />
<br />88+1 + CS WS + CS WS + CS WS + GS + "svs _ s s
<br />o D 0 D,SP 0 E ... CR WRF -
<br />
<br />s S
<br />CR WRF ,SP
<br />
<br />CS WS
<br />o 0
<br />
<br />(20) ,
<br />
<br />The term l.l svs represents total reduct ion
<br />of salt formerly added through seepage from
<br />unlined canals. The symbol \ls is the tons
<br />of salt avoided per mile of canal.
<br />
<br />
<br />Let ~C* be the given percentage of
<br />salinity reduction that will be achieved
<br />
<br />through salinity control measures. Hence,
<br />
<br />Equation 22 is rewritten more specifically
<br />as
<br />
<br />dS _ dF = (~ _ ^C*)
<br />S F C
<br />
<br />(22)'
<br />
<br />The maximization problem for Alternative 2 is
<br />formulated as:
<br />
<br />Max 22 = HA + HE - Tel
<br />
<br />subject to Equations 8', 9', lO throu~h 16,
<br />14+, l5+, l7', l8', 19, 20' and 22'.
<br />
<br />
<br />With additional constraints:
<br />
<br />n' > 1f*
<br />A,.- A
<br />
<br />n' > n*
<br />E - E
<br />
<br />(24)
<br />
<br />Equation 24 is required to guarantee that the
<br />total cost of Alternative 2 comes solely from
<br />an investment expenditure.
<br />
<br />Alternative 3
<br />
<br />This alternative would achieve requir:d
<br />water quality levels without investment In
<br />structural alternatives by reallocating some
<br />water for release for dilution purposes. The
<br />cost of this alternative is a diminution
<br />of the net return of agricultural and energy
<br />production due to a reduction of water
<br />consumptive use. The allocation of water to
<br />meet a given level of salinity reduction
<br />AC* is determined by the following model:
<br />
<br />Max Z3 = 'ITA + 'ITE
<br />
<br />subject to Equat ions 8 through 20 and 22'.
<br />
<br />Alternative 4
<br />
<br />
<br />Under this alternative, the salinity
<br />level is improved through all available
<br />control measures. The cost of this alter-
<br />native is a combination of investment for
<br />irrigation efficiency improvement (both
<br />on-farm and conveyance), desalting and
<br />ponding, and a diminution of net agricutural
<br />and energy returns. The maximization problem
<br />for this alternative is
<br />
<br />Ma x Z 4 = ~ A + ~E - TC I
<br />
<br />subject to Equations 8', 91, lO through l6,
<br />14+, l5+, l7', lB', 19, 20' and 22'
<br />
<br />The optimization models of Alternatives
<br />2, 3, and 4 will potentially give different
<br />optimal levels of agricultural and energy
<br />activities than Alternative 1. Furthermore,
<br />the best policy will satisfy the two economic
<br />criteria:
<br />
<br />l. To maintain any given measured
<br />quality, the level of each salinity control
<br />technique should be such that the quality
<br />
<br />27
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