WSP11706

• File Number: 8271.300
• Description: Colorado River Basin Salinity Control Program - General Information and Publications-Reports
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 6/1/1980
• Title: Development of Procedures to Evaluate Salinity Management Strategies in Irrigation Return Flows
• Water Supply Pro - Doc Type: Report/Study

Table 3.4. Characteristic analysis of detailed hydrosalinity models.

Reference
Ayars, J. E.
1976

'"
w

Khan, 1. A,
and Labadie,
J. W., 1979

Constituents
IIDdeled
ea+Z, Mg+Z
+ -
Na ,HCXl3
-Z
Cl-, 004
IDS

Individual
ions, TDS
and SAR of
the irriga-
ticm rerum
flews .

Major Assumptions
in salinity IIDdel

Soluble species nove freely
with soil segtlEIl.t.

Solute ccmcentrations are
constant for any soil segtlEIl.t.

Nitrogen transformations are
not considered (as it is not
a major pollutant in Grand.
Valley) .

Inorganic reactions are
based on equilibriun ch5Distry
since the reaction tines are
less than the residence time
of water in a soil segment.

Water flow and content are in-
dependent of any chemical
process.

Complete mixing occurs at
each increren.t in time and
space.

Each chemical process is in-
dependent of other processes
over a time step witll respect
to availability of component
masses.

Rate of change of mass for
each component is constant
over a time step.

Mixing cell concept is used
to calculate salt transport.
The length of cell remains
constant.

The tmSaturated zone nodel
assumes: (i) steady state
conditions, (ii) the pH of
the solution is governed by
the soil carbonate equili-
bria, (iii) soil lime is
present in sufficient quan-
tities to saturate soil
solution, (iv) =lete mixing
is assumed.

Temperature effects are not
considered.

Input data T:ime
requi.rerrents increIIHlt

Irrigation water Daily
chemical analysis.

Number, sizes and
dapth of chemistry
horizons in soil
profile.

Initial soil analy-
sis of each horizon.

Fertilization and
irrigation dates.

CEe, concentration
of gypsun in soil,
presence of lime.

Average ionic con- Annual
centration of irri-
gation water, soil-
water, and ground-
water.

O:Jmn2nts

TDS concentrations were
adequately IWdeled, but
the individual ionic
constituent concentra-
tions were not.

CaS04 - Ca003 - Ca(HC03)Z
system was not adequately
rrodeled for the soils in
the Grand Valley.

The rnanagerrent strategy
should be based on the
tacit assumption that
at least a portion of
available grotmdwater is
still usable for agri-
culture.

l~tE

Model
Application
Grand Valley,
Colorado

Lower San Luis
Rey River Basin,
Southern
California