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<br />Acknowledgments
<br />
<br />The authors thank the following people for their
<br />assistance in preparing this report: Richard p, Snyder
<br />and Eddie L.Taylor, Colorado Division of Water
<br />Resources, Water District 10; Thomas C. Simpson,
<br />SECWCD; Phillip C. Saletta, CCS: and Joseph D.
<br />Flory and Steven J, Witte, Colorado Division of Water
<br />Resources, Water Division 2. Thanks also are
<br />extended to Scott E, Howell, CCS, and Mark E. Smith.
<br />USGS, for providing technical reviews of the report.
<br />Appreciation also is extended to Sharon M. Powers.
<br />USGS, for prepming the final figures and manuscript.
<br />
<br />DESCRIPTION OF THE ORIGINAL
<br />TRANSIT-LOSS ACCOUNTING PROGRAM
<br />
<br />A clear description and understanding of the
<br />original accounting program is necessary before the
<br />changes made to the program can be described and
<br />understood, The following sections describe: (I) The
<br />system of subreaches, nodes. and stream segments
<br />used in the accounting program [and in the transit-loss
<br />study (Kuhn. 1988)]: (2) the input data requirements:
<br />(3) the computations, including the assumptions used;
<br />>nd \4) the resulting output.
<br />
<br />System of Subreaches, Nodes, and
<br />Stream Segments
<br />
<br />The study area for the transit-loss study (Kuhn,
<br />] 988) consisted of Fountain Creek and the adjoining
<br />alluvial aquifer (fig. I) that is hydraulically connected
<br />to Fountain Creek, Because of the hydraulic connec-
<br />tion, water in Fountain Creek may flow into (recharge)
<br />the aquifer, and water in the aquifer may discharge
<br />back into Fountain Creek: this process can be higWy
<br />dynamic in time and in location. To determine the
<br />transit losses associated with the TRF's. a
<br />stream/aquifer model (Land. 1977) was used in the
<br />transit-loss study (Kuhn. 1988), To apply the
<br />stream/aquifer model and the transit-loss study results
<br />(the accounting program). the study reach (fig, I) was
<br />divided into a system of subreaches. nodes, and stream
<br />segments (fig. 2) because of the variable hydraulic and
<br />hydrologic conditions along Fountain Creek,
<br />The reasoning used in defining the hydrologic
<br />system (fig. 2; table I) is described ili Kuhn (1988,
<br />
<br />p. 14-19.29). For this report, the following details are
<br />provided: (I) Fourteen subreaches, 16 nodes, and 4
<br />stream segments were defined; (2) the subreaches are
<br />parts of the study reach having uniform hydraulic and
<br />hydrologic characteristics (Kuhn. 1988. l1.ble 3);
<br />(3) the nodes, which delimit the subreaches, primarily
<br />are defined on the basis of locations of streamflow-
<br />gaging stations and streamflow diversions along Foun-
<br />tain Creek; (4) the set of subreaches between the
<br />gaging-station nodes (fig, 'I; table I) are the stream
<br />segments (not specifically indicated in fig. 2 or
<br />table I); and (5) the subreach (not numbered in fig. 2
<br />and table I) between nodes A and A I is used in the
<br />accounting program only for purposes of streamflow
<br />routing. not for transit-loss computations.
<br />In the transit-loss study (Kuhn. 1988), three
<br />types of loss were considered: bank storage, channel
<br />storage, and evaporative, The magnitude of each of
<br />these types of loss was estimated for each of the 14
<br />subreaches for a variety of streamflow conditions in
<br />Fountain Creek, ranging from \ to \00 ft3/s for TRF
<br />and from 0 to 1.000 ft3ts for NSE The bank-storage
<br />and channel-storage transit losses were estimated
<br />using the stream/aquifer model, and the evaporative
<br />transit losses were estimated using pan-evaporation
<br />data: the methods and results of \hese analyses are
<br />described in Kuhn (1988). The results of these anal-
<br />yses, which are coded into the accounting program,
<br />could be used to provide a daily estimate of: (I) The
<br />quantity of TRF and NSF at each of the [5 nodes
<br />(table I. excluding node A) and (2) the quantity of
<br />transit loss associated with the TRF as it is routed
<br />through each subreach from the upstream node to the
<br />downstream node of the subreach (fig, 2; lable I),
<br />It is important to remember that the accounting
<br />program is not the stream/aquifer model, nor does the
<br />program contain any of the components or algorithms
<br />of the stream/aqui fer modeL Rather, the accounting
<br />program incorporales the results of using the
<br />stream/aquifer model; these results quantify the transit
<br />losses for a large range of TRF and NSF conditions in
<br />Fountain Creek.
<br />
<br />Input Data Requirements
<br />
<br />To compute estimated quantities of TRF and
<br />transit loss using the accounting program, the
<br />following data are required: (I) Daily quantities of
<br />TRF and native return flow discharged into Fountain
<br />
<br />4 Descrtpt\ons 01 the Progyam Changes {1989-97) and a User Manual for a Transit-Loss Accounting Program
<br />Applied to Fountain Creek Between Colorado Springs and the Arkansas River, Colorado
<br />
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