Laserfiche WebLink
<br /> <br />002031 <br /> <br />. <br /> <br />concentrations depend on initial conditions, boundary inputs, <br />river reach and reservoir inputs as well as operating policies. <br /> <br />The word export already denotes the removal of water from the <br />river and all exports should be positive quantities. However, <br />there are no program checks. Negative exports will result <br />in the addition of both water and salt to the system. <br /> <br />Exports may be used to account for diversions to locations <br />outside the basin, or to temporary storage facilities such as <br />aquifers or offstream surface storage. <br /> <br />Variable exports (Cards 16-1 to 16-3). - These are identical to <br />the exports described above except their magnitude is not <br />firmly set. Instead, maximum or limiting values are specified <br />and the actual size depends on the availability of water in <br />the reservoirs. Either the excess water or spill option <br />described in the preceding subsection, or both, may be used <br />to determine availability. <br /> <br />. <br /> <br />Irrigations (Cards 14-1 to 14-5). - An irrigated acreage <br />(1,000 acres), quantity of water added or subtracted from <br />the system, plus a salt pickup rate (tons/acre/~onth) are <br />specified to account for irrigation projects. <br /> <br />A positive flow denotes an increase of water in the river <br />corresponding to the case where diversions are less than <br />return flows while a negative flow signifies a decrease in <br />stream flow. If the pattern of diversions and returns are <br />neglected, the flows may be set equal to the consumptive use <br />to account for water depletions. It should be noted that <br />the salinity of diversions and returns are not explicitly <br />considered. However, a net water depletion does produce an <br />increase in concentration in the river. <br /> <br />The salt pickup rate is multiplied by the acreage to yield <br />the addition or removal of salt due to chemical processes <br />in the soil system. A positive rate results in the addition <br />of salt to the river due to dissolution and leaching while <br />a negative rate results in a depletion due to precipitation <br />and storage within the soil system. Pickup rates and the <br />resulting quantities of salt are independent of the magnitude <br />and sign of the flows. <br /> <br />. <br /> <br />Inputs of each type are numbered consecutively using integers <br />starting with one and proceeding up to the maximum. These <br />numbers are used by the program for subscripting purposes. An <br /> <br />2-18 <br /> <br />