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<br />Uilil435
<br />
<br />sums the diversions fo, all ditches within the
<br />stream se.gment.
<br />
<br />6. SS_K6 (fig. 4), which is the stream-segment
<br />channel length, in ntiles. SS_K6 is derived from
<br />the subreach channel lengths that were deter-
<br />ntined in the transit-loss study (Kuhn, 1988,
<br />table 3). The channel lengths for all subreaches
<br />within a stream segment were summed and are
<br />included in the program code,
<br />
<br />The unknown quantity in the stream-segment
<br />computations is SS_U1 (fig. 4); the following steps are
<br />used in \he stream-segment computations to derive the
<br />unknown quantity;
<br />
<br />I. Compute an initial estimate of NSF at the down-
<br />stream gaging station; this estimate is equal to
<br />SS_K4 (the total streamflow at the downstream
<br />gaging station) minus SS_K2 (the TRF at \he
<br />upstream gaging station) (see the "Assumptions
<br />Used in the Computations" section, p. 8).
<br />
<br />2. Compute a revised estimate of NSF at the down-
<br />stream gaging station; this estimate is equal to
<br />SS_K5 (the total NSF diversion in the stream
<br />segment) plus the result from computation step I.
<br />The revised estimate of NSF at the downstream
<br />gaging station is the conditional NSF, provided
<br />there had not been any NSF diversions in the
<br />stream segment.
<br />
<br />3. Compute the estimated total NSF loss 0' gain in the
<br />stream segment; the total NSF loss or gain is
<br />equal to SS_K3 (\he NSF at the upstream gaging
<br />station) ntinus the result of computation step 2.
<br />
<br />4. Compute SS_U I [the estimated NSF loss or gain in
<br />the stream segment, in cubic feet per second per
<br />ntile (fig. 4)], which is equal to the result from
<br />computation step 3 divided by SS_K6 (the
<br />stream-segment channel length).
<br />
<br />When the stream-segment computations are
<br />completed, the accounting-program computations
<br />proceed to the subreach computations; \he ,esult from
<br />computation step 4 of the stream-segment computa-
<br />tions is used in the subreach computations. Because
<br />node E (fig. 2, table I) is the last gaging station, the
<br />stream-segment computations are not made for
<br />subreach 14 (the,e is no downstream gaging station to
<br />define a stream segment); therefore, NSF loss or gain
<br />is assumed to be zero in subreach 14 (Kuhn, 1988,
<br />p.81).
<br />
<br />.(."
<br />
<br />Subreach Computations
<br />
<br />The subreach computations are diagramed in
<br />figure 5; to perform the subreach computations, the
<br />following subreach known quantities (SR_Kx, where
<br />x is a number) need to be defined:
<br />I. SR_KI (fig. 5), which is the TRF at the upstream
<br />node. For most subreaches, SR_K 1 is equal to
<br />SR_U3 (the TRF at the downstream node) from
<br />the computations for the previous subreach
<br />(fig. 5). For a subreach with the upstream node at
<br />node AI, B, C, D, or E (fig. 2; table I), SR_KI is
<br />equal to SS_K2 (the TRF at the upstream gaging
<br />station) from the stream-segment computations
<br />(fig. 4).
<br />
<br />2. SR_K2 (fig. 5), which is the NSF at the upstream
<br />node. For most subreaches, SR_K2 is equal to
<br />SR_UI (the NSF at the downstream node) from
<br />the computations for the previous subreach
<br />(fig. 5). For a subreach with the upstream node at
<br />node B, C, 0, or E (fig. 2; table I), SR_K2 is
<br />equal to SS_K3 (the NSF at the upstream gaging
<br />station) from the stream-segment computations
<br />(fig. 4); howeve,r, if the upstream node is node
<br />AI, then SR_Kl is equal to the sum of (I) the
<br />daily mean discharge at station 07105500
<br />(node A, table I), (2) the native return-flow
<br />discharge at the CCS WWTF, and (3) the esti-
<br />mated NSF loss or gain between nodes A and Al
<br />(fig. 2; table I). The estimated NSF loss or gain
<br />between nodes A and Al is computed by multi-
<br />plying SS_Ul [the streanl-segment NSF loss or
<br />gain (fig. 4)] by the channel length between
<br />nodes A and Al (0.6 nti).
<br />3. SR_K3 (fig. 5), which is the total NSF diversion
<br />between the nodes. The NSF diversions are input
<br />individually for each ditch, and the program
<br />sums the diversions for all ditches within the
<br />subreach.
<br />4. SR_K4 (fig. 5), which is the subreach channel
<br />length, in miles. Values for SR_K4 were deter-
<br />ntined in the transit-loss study (Kuhn, 1988,
<br />table 3) and are included in the program code.
<br />The unknown quantities in the subreach compu-
<br />tations are SR_U1, SR_U2, and SR_U3 (fig. 5); \he
<br />following steps are used in the subreach computations
<br />to derive the unknown quantities:
<br />I. Compute the NSF at \he upstream node that is to be
<br />routed through the subreach to the downstream
<br />
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<br />DESCRIPTION OF THE ORIGINAL TRANSIT-LOSS ACCOUNTtNG PROGRAM 9
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