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<br />node. The NSF to be routed is equal to SR_K2
<br />(the NSF at the upstream node) minus SR_K3
<br />(the total NSF diversion in the subreach) (fig. 5).
<br />
<br />2. Compute the subreach NSF loss or gain, which is
<br />equal to the product of SR_K4 (the subreach
<br />channel length) (fig. 5) times SS_Ul (\he stream-
<br />segment NSF loss or gain) (fig. 4). The subreach
<br />NSF loss or gain for subreach 14 is assumed to
<br />be zero (see the "Stream-Segment Computa-
<br />tions" section, p. 8-9).
<br />
<br />3. Compute SR_Ul (\he NSF at \he downstream
<br />node), which is equal to the sum of the results
<br />from computation steps I and 2. Because the
<br />downstream node of a subreach becomes the
<br />upstream node for the next subreach, SR_U1
<br />becomes SR_K2 (the NSF at the upstream node)
<br />in the computations for the next subreach (fig. 5).
<br />
<br />4. Compute SR_U2 (fig. 5). As described in the
<br />"System of Subreaches, Nodes, and Stream
<br />Segments" section (p. 4), transit loss consists of
<br />bank-storage loss, channel-storage loss, and
<br />evaporative loss. Because Fountain Creek and
<br />the adjoining alluvial aquifer are bydraulically
<br />connected, Kuhn (1988, p. 59-{i5) determined in
<br />the transit-loss study that some of the bank-
<br />storage transit loss (aquifer recharge) on a given
<br />day would return to Fountain Creek over time
<br />(aquifer discharge); this return would be a gain
<br />from bank storage. Kuhn (1988, p. 66, 72) also
<br />concluded that the channel-storage transit loss on
<br />one day became an equivalent gain from channel
<br />storage on the next day. The results of the transit-
<br />loss study (Kuhn, 1988) enable computation of
<br />the bank-storage and channel-storage compo-
<br />nents of transit loss or gain and computation of
<br />the evaporation-loss component of transit loss;
<br />these results are included in the computer code of
<br />the subreach computations. The sum of all the
<br />losses and gains results in the net subreach transit
<br />loss or gain (SR_U2 in fig. 5). SR_U2 is negative
<br />if there is a net transit loss and is positive if there
<br />is a net transit gain.
<br />
<br />5. Compute SR_U3 (the TRF at the downstream
<br />node), which is equal to \he sum of SR_Kl (\he
<br />TRF at the upstream node) and SR_U2 (the result
<br />from computation step 4). Because the down-
<br />stream node of a subreach becomes the upstream
<br />node for the next subreach, SR_U3 becomes
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<br />SR_KI (\he TRF at the upstream node) in the
<br />computations for the next subreach (fig. 5).
<br />
<br />The subreach computations are repeated for
<br />each subreach within the stream segment. When
<br />computations are completed for all subreaches within
<br />a stream segment [the downstream node is at gaging
<br />station (node B, C, or D, table I)], the program
<br />computations retum to the stream-segment computa-
<br />tions; however, if the downstream node is at station
<br />07106500 (node E, table I), then the subreach compu-
<br />tations are continued for the last subreach (see the
<br />"Stream-Segment Computations" section, p. 8-9).
<br />When computations have been completed for all 14
<br />subreaches, the total transit loss and the estimated
<br />quantity of TRF at the mouth of Fountain Creek are
<br />known.
<br />
<br />Program Output
<br />
<br />Output for the original accounting program
<br />presented detailed results for (I) the TRF quantities,
<br />(2) the NSF quantities, and (3) the input data quanti-
<br />ties (table 2). The output presented results for the
<br />transit-loss computations and streamflow accounting
<br />for each subreach; however, in adntinistering the TRF
<br />use and reuse program, only the final results (at
<br />subreach 14) are needed. The discrepancy in the NSF
<br />discharge value described in the "Assumptions Used
<br />in the Computations" section (p. 8) can be seen in the
<br />output. The native inflow for subreaches 3, 7,12, and
<br />14 is different from the native outflow of the previous
<br />subreach, whereas the native inflow for the other
<br />subreaches (2, 4--6, 8-11, and 13) is the same as the
<br />native outflow in the previous subreaches.
<br />
<br />STREAMFLOW-GAGING STATION
<br />NETWORK ON FOUNTAIN CREEK
<br />
<br />The gaging-station network on Fountain Creek
<br />originally consisted of five stations between the CCS
<br />and the Arkansas River (figs. 2 and 3; table I). A sixth
<br />gaging station (station 07105530 in fig. 3) was added
<br />to the network in 1995; this station actually was estab-
<br />lished in October 1989 to obtain discharge and water-
<br />quality data, but was not incorporated into the
<br />accounting program until 1995. Each gaging station is
<br />equipped with a data-collection platform that scans a
<br />scnsor for gage-height (stage) data every 15 minutes,
<br />
<br />12 Descriptions ot the Program Changes (1989-97) and a User Manual for a Translt~L-oss Accounting Program
<br />Applied to Fountain Creek Between Colorado Springs and the Arkansas River, ColoradO
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