Laserfiche WebLink
MI <br />A theoretical bank storage curve was developed from an equation <br />given by Ferris, Knowles, Brown, and Stallman (1962); <br />Q = 0.0692 s ✓ tT (1) <br />in which Q is bank storage for both sides of the stream in cubic feet <br />per second per mile, s is the abrupt change of stage in the stream in <br />feet, S is the storage coefficient, T is transmissivity in square feet <br />per day, and t is time in days since the abrupt change of stage occurred <br />in the scream. Increases in stream stage result in positive values of <br />s and Q which indicate water entering bank storage; water will leave <br />bank storage when the stream stage declines. Water leaving bank storage <br />will.be discussed in the section on the recession following reservoir <br />releases. <br />To estimate the transmissivity (T) near Salida, the observed bank <br />storage rate (Q at time t, s and an assumed S, were used in equation <br />1 for elapsed times (t) ranging from 5 minutes to 21 hours. The average <br />T by this method, and the assumed value of S used in its derivation, <br />were then tested using two other equations given by Ferris, Knowles, <br />Brown, and Stallman (1962): <br />x <br />r(� 2 <br />s = s I1 - T 2 T� e 2 du] = s (2) <br />LL �r <br />0 <br />and <br />U2 = x 2s (3) <br />4Tt <br />in which x is the distance of the well from the stream in feet, s is the <br />observed change of head in the well in feet, and D(u)h is the compli- <br />mentary error function which is given for calculated values of u <br />Equations 1 and 3 test T and S because equation 1 evaluates the product <br />ST and equation 3 evaluates the ratio S:T. Using this trial and error <br />method of evaluating T and S in conjunction with the observed bank <br />storage rate, the average transmissivity in the vicinity of Salida was <br />estimated to be 4,760 ft (feet squared) per day (35,600 gallons per <br />day per foot) and the storage coefficient to be 0.15. <br />Equation 1 shows that bank storage is proportional to s the stage <br />change in the river. In the preceding analysis of observation well data, <br />s was determined from staff gage readings at each site. To extend the <br />bank storage relationship for different antecedent river conditions and <br />release discharges, the expected change in river stage was evaluated on <br />the basis of miscellaneous mainstem discharge measurements and the stage - <br />discharge relationships at mainstem gaging stations. <br />16 <br />