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<br />OJiH34
<br />
<br />Once initiated, the accounting program queries
<br />the user for the required input data: (I) The TRF and
<br />the native return-flow quantities discharged at the CCS
<br />WWTF, (2) the discharge at each gaging slation
<br />(table I, fig, 3), and (3) the diversion at each ditch
<br />(table I), These data arc input manually to the
<br />program for each day of transit-loss computations:
<br />however. the diversion dala, once input, only need to
<br />be reentered when the diversions change from the
<br />previous day. All input data, the accounting program
<br />computations. and the output results are expressed in
<br />cubic feet per second, unless noted othelWise.
<br />
<br />Program Computations
<br />
<br />.:'
<br />
<br />In computing the estimated quantities ofTRF in
<br />Fountain Creek and the associated transit losses. the
<br />accounting program uses IwO sets of computations.
<br />The first set of computations is made belween any two
<br />adjacent gaging stations (stream-segment computa-
<br />tions); these computations estimate the loss or gain in
<br />NSF between the two adjacent gaging stations, The
<br />second set of computations is made between any two
<br />adjacent nodes (subreach computations); the actual
<br />transit-loss computations are made in the subreach
<br />computations, using the result from the stream-
<br />segment computations, The stream-segment computa-
<br />tions are completed for a stream segment, then the
<br />subreach compulations are completed for each
<br />subreach within the stream segment. When the
<br />subreach computations are compleled for all
<br />subreaches within a stream segment, the stream-
<br />segment computations are repeated for the next stream
<br />segment, followed again by the subreach computa-
<br />tions; the process continues until computations are
<br />completed downstream through subreach 14,
<br />
<br />'.
<br />
<br />Assumptions Used in the Computations
<br />
<br />To compute estimated transit losses using the
<br />accounting program, an assumption must be made in
<br />the stream-segment computations that the quantity of
<br />TRF at the downstream gaging station is the same as at
<br />the upstream gaging station. This assumption is neces-
<br />sary because, at this point in the computations, the
<br />quantity of TRF at the downstream gaging station is
<br />not known, Although this assumption results in some
<br />error in estimating the loss or gain in NSF between the
<br />gaging stations, these errors are not substantial (Kuhn,
<br />
<br />1988. p, 8\\), Because of this assumption. the
<br />computed quantity of NSF at the end of the down-
<br />stream subreach within a stream segment is somewhat
<br />different from the NSF at the beginning of the next
<br />stream-segment computations (see the "Program
<br />Output" section, p, 12), This discrepancy in NSF
<br />computation has been corrected in the program
<br />version currently (1997) in use (see the "Changes to
<br />Program OUlput" seclion, p, 22). To perform the
<br />transit-loss computations, the input data also are
<br />assumed to be accurate,
<br />
<br />Stream-Segment Computalions
<br />
<br />After the data are input. the accounting-program
<br />compulations begin with the stream-segment compu-
<br />tations, which are diagramed in figure 4. To perform
<br />the stream-segment computations. the following
<br />stream-segment known quantities (SS_Kx, where x is
<br />a number) need to be defined:
<br />
<br />1. SS_K l (fig. 4). which is the total streamflow at the
<br />upstream gaging station, If the upstream gaging
<br />station is station 07105500, then SS_K I is equal
<br />to the sum of the daily mean discharge at station
<br />07105500 and the total return flow (sum of TRF
<br />and native return flow) discharged into Fountain
<br />Creek at the CCS WWTF; othelWise, SS_KI is
<br />equal to the daily mean discharge at the upstream
<br />gaging station,
<br />
<br />2, SS_K2 (fig, 4), which is the TRF al the upstream
<br />gaging station, If the upstream gaging station is
<br />station 07105500. then SS_K2 is equal 10 the
<br />TRF discharged at the CCS WWTF; othelWise,
<br />SS_K2 is equal 10 SR_U3 (the TRF at the down-
<br />stream node) from the last subreach computation
<br />of the previous stream segment (see fig. 5 and the
<br />"Subreach Computations" section. p, 9-12),
<br />
<br />3. SS_K3 (fig, 4), which is the NSF at the upstream
<br />gaging station, SS_KJ is equal to SS_KI minus
<br />SS_K2.
<br />
<br />4, SS_K4 (fig. 4). which is the total streamflow at the
<br />downstream gaging station. SS_K4 is equal to
<br />the daily mean discharge at the downstream
<br />gaging station,
<br />
<br />5, SS_K5 (fig. 4), which is the total NSF diversion in
<br />the stream segment. The NSF diversions are
<br />input individually for each ditch and the program
<br />
<br />8 Descriptions of the Program Changes (1989-97) and 8 User Menual for 8 Transit-Loss Accounting Program
<br />Applied to Fountain Creek Between Colorado Springs 8nd the Arkansas River, Colorado
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