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Show Waddell and Fields- Model for Evaluating the Effects of Dikes on the Water and Salt Balance of Great Salt Lake 25 the Weber River, and site 10170490 on the Jordan River. Efforts were made to extend these relationships to the refuge outlets on the Jordan and Bear River systems, but the data- collection period was inadequate. A summary of the data collected at the refuge outlets is given in tables 14 and 15. The dissolved load within the diked area at any time step ( t) can be estimated as follows: Dissolved load = initial load + inflow load - outflow load LD ( t) = LD ( t - 1) + ( ID( t)) ( CI) - ( OD ( t)) ( LD ( t - 1)/ VD ( t - 1)) where ID ( t) is the inflow to the diked area, CI is the concentration of the inflow, OD ( t) is the outflow from the dike, and ( LD ( t - 1)/ VD ( t - 1)) is the concentration of dissolved solids of water within the diked area. VD ( t - 1) is the volume within the diked area at the end of the previous time step ( t - 1). Due to the limitations of the available water- quality data, the load of dissolved solids or the concentration of dissolved solids in the diked area cannot be estimated precisely. The model treats the salt balance of the diked area from the standpoint of an inflow- outflow balance with complete mixing, and no allowance is made for any stratification or chemical changes due to interaction with the sediments or solution of entrapped brines or residual salts. Because the degree of inaccuracy created by the assumptions is not known, the concentrations predicted by the model should be regarded not as absolute but as relative indexes by which to compare various diking alternatives. A particular diking alternative can be evaluated from the standpoint of dissolved- solids content by comparing the concentrations predicted by the various diking alternatives. The salt balance for the north and south parts of Great Salt Lake is complicated because of the two- directional flows through the causeway, precipitation of sodium chloride and re- solution of sodium chloride deposits, and the presence of two layers of brine with different chemical characteristics in the south part. The total dissolved plus precipitated salt load in the north and south parts ( TL) can be described by the following equation: TL = LS + LSDL + CLSPPT + LN + CLNPPT + LD where LSDL is the load of dissolved solids in the deep layer of the south part, CLSPPT and CLNPPT are the precipitated salt loads in the south and north parts, respectively, and LS, LN, and LD are the dissolved- solids loads in the south, north, and diked parts, respectively. Now TL can be estimated by the above equation when all the parameters on the right side of the equation are known. In the fall of 1972, as previously discussed on page 4, the total dissolved plus precipitated load ( TL) in Great Salt Lake was about 5.5 billion tons ( 4.99 billion t). The dissolved- salt load in the deep layer of the south part ( LSDL) has been computed as 0.3 billion tons ( 0.27 billion t), and it has been essentially constant since it was first observed ( Waddell and Bolke, 1973, p. 35). Now the equation can be rearranged so that LS + CLSPPT = 5.2 - LN - CLNPPT - LD For the south part, the dissolved- salt load ( LS) can be estimated from the following equation: New dissolved load = initial load + inflow load from diked part - outflow load from south part + inflow load from north part + salt re- solution in south part - precipitated salt load in south part LS ( t) = LS ( t - 1) + ( OD ( t)) ( LD ( t - 1))/ VD ( t - 1) - ( M) • ( LS ( t - 1))/ VS ( t - 1) + ( N) ( LN ( t - 1))/ VN ( t - 1) + ASOLS ( t) - LSPPT ( t) For the north part, the dissolved- salt load can be estimated from the following equation: New dissolved load = initial dissolved plus precipitated load - new dissolved- solids load in south part + salt re- solution in north part - precipitated salt load in north part LN ( t) » LN ( t - 1) + ( M) ( LS ( t - 1))/( VS ( t - 1)) - N (( LN ( t - 1))/ VN ( t - 1) + ASOLN ( t) - LNPPT ( t) Now, ASOLN ( t) and LNPPT ( t) must be computed using the equations developed by Waddell and Bolke ( 1973, p. 34). ASOLN ( t) and LNPPT ( t) can be assumed to be negligible to initially estimate LN ( t). Then LN ( t) can be tested to determine if the total load in the north part exceeds the limiting salt load necessary for saturation. The limiting salt load necessary for saturation at a given lake volume was determined by Waddell and- Bolke ( 1973, p. 34) to be 483- VN for the north part and 483- VS for the south part. If it exceeds 483 * VN, then precipitation will occur and ASOLN ( t) will become zero. The amount of precipitation ( LNPPT) must then be subtracted from the first estimate of LN ( t). This procedure is repeated until the iterative values converge to a solution. If the quantity ( LN ( t)) is less than 483- VN, then the brine is under saturated and re- solution of the |