WSP09047

• File Number: 8276.130
• Description: Grand Valley Unit - Colorado River Basin Salinity Project
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 2/17/1983
• Title: Alternative Summary Stage Two -- Grand Valley Unit
• Water Supply Pro - Doc Type: Report/Study

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Grand Valley Unit, Stage Two
Colorado River Salinity Control Project, Colorado

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Salt and Water Budget - Explanation

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A salt and water budget is very similar to an operation study. You have the
added complexity of having to account for salts as well as water. This
requires that every volume have an associated quality with it. Using a mass
balance, we try to balance inflows and outflows. Carrying the quality along,
the difference in tons in and tons out is your salt "pickup." This is what
we commonly call a "gross" budget.

The top portion of the two internal budget printouts 1S essentially a "gross"
budget. We look at the individual inflows and outflows with a separate
program which only does a gross budget (first printout>. The "gross" budget
insures that a water balance exist. The purpose of the internal budget is to
define the apportionment of ground-water and surface water inflows and
outflows so that sources of salt loading may be identified. The following is
an explanation of the columns on the printouts.

Gross Budget Column Explanation

The first page is the water portion of the budget, the second page is the
tons portion, and the third page is the respective water qualities. The
columns correspond from page to page by their namesakes. PRECIP is acre-feet
of precipitation on the watershed, using Walker Field data. AIN220 is an
acronym for "A" canal, "IN" for inflow, and "220" for watershed number 220.
The other "IN" are the canal inflows via the C, D,and F canals. The "1M"
columns are imported flows via the respective systems. UGI220 is the ungaged
inflows (see column 2 of internal budget explanation). "Total" is the total
inflows to the watershed.

The "CON" is the total consumptive use (see internal documentation).
canal outflows are "aT" columns. The exports are the "EX" columns.
"GV0220" column is drain outflow at the mouth of the watershed.

The
The

CA0220 is the ungaged outflows, mostly through the cobble aquifer. "UNACCTD"
is the unaccounted flows, equal to total inflows minus total outflows. On
the second page, "PICKUP" is the tons of sali: in minus the tons of salt out.

Internal Budget Column Explanation

Column 1. The canal inflows are summed. The canal inflows are either
estimated or measured. Quality of the canal water is based on appropriate
stations. The quality of the columns is the flow weighted mean of the summed
individuals.

Column 2. Ungaged surface inflows are prorated to the U.S.G.S. gage at
West Salt Creek based on a study by 750. Ungaged ground-water inflows are
based on wells in three alluvial areas above the canal system. The quality
is flow weighted.

Column 3. Imports are either measured or based on a
Sources of Imports were identified by a map survey.
same as column one.

Q/A
The

relationship.
quality is found

the

Column 4. Precipitation is presently based on Walker FiE,ld - NOAA.