WSP00380

• File Number: 8149.100
• Description: Miscellaneous Small Projects-Project Studies - NRCS-Ft Lyon Canal Co-Limestone-Graveyard Creeks
• State: CO
• Basin: Arkansas
• Water Division: 2
• Date: 9/1/1992
• Author: US Dept of Agricultu
• Title: Lower Arkansas River Basin - Water Quality Study - Colorado
• Water Supply Pro - Doc Type: Report/Study

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0025:$6

23

V. ALTERNATIVE PLANS

A. summary of system Model Runs

As previously discussed, the system model is a monthly water
budget spreadsheet analysis for individual canal systems.
It was run for non-project conditions on 16 canal systems,
see previous listing.

The greater emphasis in this study is the salinity level in
the Arkansas River. The system model was intended to
provide changes in depletion as a result of project actions
on-farm. The impact on deletion were to be used in the
river model to check effects on the river. with this in
mind, the main emphasis of the system model is to establish
changes in depletion due to project action and not
necessarily to spend a great deal of time in modeling exact
non-project conditions. Therefore, conveyance system
efficiencies and on-farm irrigation efficiencies were only
estimated.

The estimated values were assumed to apply to all systems
which, in actuality, do not reflect exact non-project
conditions, but will suffice to test changes due to a
different set of values estimated for project conditions.

Non-project condition on-farm irrigation efficiencies were
assumed to be 40 percent for all canal systems. A selected
alternative treatment project includes sufficient on-farm
improvements to upgrade the irrigation efficiency to 55
percent. The spreadsheet was re-run for all canal systems
with only the on-farm irrigation efficiency changed. The
conveyance system efficiency was assumed to be 75 percent
for all canals for non-project conditions as well as for
project conditions. See Tables 4 and 5.

The fOllowing summary table shows values of selected
parameters that a project would produce from on-farm
irrigation efficiencies of 55 percent.

Also included is a summary table for non-project conditions.
Full printouts of the spreadsheets are on file in the Soil
Conservation Service State Office.

Since computed crop consumptive use is important to the
river model, the comparative plots of consumptive use for
without project and with project conditions are shown in
Figures 4, 5, 6, and 7. The graphs reflect data for the
independent canals and the three groups of canal systems
having water supply interaction.