•
USDA SALINITY
CONTROL
AND
ENVIRONMENTALASSESSMENT
VI RGIN VALLEY SUBEVALUATION UNIT
Colorado
Of The Vi rgi n Ri ver
River Basin Salinity
Prepared
Soil
Area
Program
by
Conservati
on Servi
P. O. Box 4850
Reno, Nevada 89505
ce
Telephone
Code (702) 784-5304
Assist~d
Science
Uni t
Control
by
U.S •. Sai'i ni ty Laboratory
and Education
Administration
-Agricultural
Riverside,
California
of the
Uni ted States
Departrrent
of Agri culture
Prepared
under Title
Salinity
Control
II of the Colorado
River
Act, Public
Law 93-320
April
1981
•
Researr:h
Basin
CONTENTS
Page
FOREWORD.
SUMMARY
i
. . . . • . . . . . . . . . • . . . . . • . . . . . . . . . . . . • . . . • . • • . • . . • . . • . . . . . . • • . . . .
..••..•.•.......•.......•.•.••..•.•...•..
INTRODUCTION.
. . ..
. ...
I;)
. .•
..
..
..
. . . . . . . . ..
. ..
..
. . ..
•
•
•
•
•
•
. . . . . ..
•
•
..
•
•
•
•
•
•
•
. . . . . ..
•
•
•
•
••
. . . . .
Authority for Investigation.........................................
;
ii
1
1
Object; ve and Scope. ~;.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
Public
4
Involvement
PrOcess................
7
7
SETTING ....
Location ..
Natural Environmental
10
10
Characteristics.
i
Physiography
and Geology ..
Cl mate ••••••••
Water Resource ..
Surface Water ..
Ground Water.
Water Use ....
Water Budget.
Water Quality.
Sa It Budget ...
Irrigation Systems
Littlefield ..
14
14
15
16
16
16
18
18
and
23
Practices.
23
28
...
Mes"quite ....
Bunkervi 11 e.
Rivrrside ...
29
.".
Irrigation Methods
·Land ·Resource
"
in Virgin
Valley.
'.' .
Soil Survey and Land Classification
Erosion and Sediment ...
Biotic Resources.
Fisheries.
Wildlife ...
. ..
.'.:...
..
Vegetation ..
Recreation
Resources.
Social and Economic Characteristics.
Popul at; on
~
Cultural, Social arid Economic
Emp 1oyment .........•......
Historic and Archeologic ..
.
Factors ..
PROBLE~lS AND NEEDS ....•...........................
Problems and Needs Associated
With Salt Loading ..
Sources of Salts .. i
Amounts of Salts ...
Control Potential
On farm
.
Off-Farm
.
Problems and Needs Associated
with Erosion and Sedimentation.
Treatment Opportunities
for Erosion Problems ....
Problems and Needs Associated
with Water Resource.
30
31
-31
31
35
36
36
37
37
38
39
39
39
40
41
42
42
43
49
49
49
51
52
54
55
ALTERNATIVE
Future
PLANS
Wi thout
"
Sa 1 inity
57
Program
62
Alternative
1."
"
a t ve 2............................................................
67
64
Comparative
69
i
A 1 tern
Analysis
for Plans
RECOMMENDED
PLAN AND IMPLEMENTATION
PROGRAM
Pub 1; c Recommenda
ons
Basis for Selection of Recommended
Plan
Additional
Research and Demonstration
Needs
Effects
of Recommended Pl an
74
t;
Impl ementati
8 I BL
I OGRAPHY
I •••
I I •••
I·'
I •••
74
••••••••
74
75
76
on Program
77
. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . ..
81
APPENDICES
Appendix
Appendix
Appendix
A - Environmental
Evaluation - Inventory Worksheets
B - Best Management
Practices
C - Biotic Communities
and Major Wildlife Resources:
FIGURES
i
iv
Fi gure 1.
Locat on Map................................................
Fi gure
Figure
Fi gure
Figure
Land Ownershi p
Program Area Map.•..........................................
Geo 1ogi c Secti on
Geologic
Map
2.
3.
4.
5.
A-l
8-1
C-l
8
9
·12
13
Figure
Figure
Figure
6.
Water Quality Measuring Stations
7.
Irrigated Land, Littlefield
Area, Arizona
8.
Irrigated Land, Me~quite Area, Arizona-Nevada
~'1'1:-~7-: ::n:'c::,r,:-t""::
•...,. ..... ~.~..,. ..··B'"::,~..:u..
A·,.;+~.;:~·,;;i·..,.·:.~\:;:·~-'
'.;;.<w;:~'l:'~'~
\ ,';,:';,
.....:>, •. ~-:': .•.•..::._._- ..-;-..-.,=---:
: .,••••••••.••••••
;"·,F·i~~ltr·e"'·
..::;1·-.~'::·_~~~~~.:1",.rFl·ga
~':$., .'".;t)un:.iS~~-"'(-1-:.L:1:.:~~4.:
..t;_~.~:"'-.:..~;:~~~~-:!;~;·""'·
..'_·,i; ..r.,ti-:;.'.'
Figure 10:
Irrigated Land, River·s.ide, Nevada .. :
~:~ ~
t'
·· ..
Figure 11.
Fi gure 12.
Soils
Map
Figure
Figure
Figure
Figure
13-A
13-B
13-C
13-0
Agriculture
Agricultural
Agricultural
Agricultural
Figure
14.
Erosion
A 1 te
Table
2.
·...............................•...........
Sa'·'Tt .:.S~&l1ro-eS ••.•.
Annual
34
44
~ ••••.•••
I ••••••••••
Land With Saline Soils, Littlefield
Area
Land With Saline Soils, Mesquite Area
Lands With Saline Soils, Bunkerville
Area
Lands with Saline Soils, Riverside Area
0 •••••••••••••••••••••••••
45
46
47
48
Areas
Level
i
rna t ve
Summary
A·'
22
24
25
26
27
53
of Funding
Installation
Period,
~ . . . . ..
vi;
ans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
ix
of Costs,
tern at; ve
for 10-Year
2
P1
Benefits
and Physical
Effects
of
Table
Table
Table
Table
3.
4.
5.
6.
Summary Ratings, Environmental
Evaluation
Water and Salt Budgets, Present Conditions
x
17
Chemical
Chemical
20
Table
Table
Table
Table
Table
Table
Table
7.
8.
9.
10.
11.
12.
13.
Chemical Composition,
Ground Water
Onfarm Irrigation Water Management Analysis
(IRMA)
Water and Salt Budgets for Alternative
Plans
Economic Development
Account, Alternative
2
Environmental
Quality Account, Alternative
2
Other Social Effects Account, Alternative
2
Implementation
Program - Salinity Control Practices
Composition,
Composition,
Virgin
Ground
River
Water
Surface Waters
at WPRS Proposed
Sarri er Site
I' 20
21
58
59
70
71
73
80
1
INT ROD UCTI ON
2
3
Authori ty for
Investi gati on
The
Colorado
River
Basin
24,
1974
authorized
USDA
4
5
6
June
7
along
8
Protection
9
Nevada,
with
Salinity
to participate
the U. S. Department
Agency
(EPA)
New Mexico,
10
act
directs
11
of Agriculture
12
in implementing
13
programs
the Secretary
14
stream
on-the-farm
from
Imperial
the
Title
research
and
improvements
on
the
(Public
of the
Colorado
the
II (Section
salinity
investigations
Colorado,
203)
with
management
signed
Environmental
California,
demonstration
and
Laltl93-320)
control
and
Interi or to cooperate
objectives
Dam
(USDI)
of Arizona,
Wyoming.
out
Act
in salinity
Interior
states
of the
in carrying
to further
of
in the
·Utah, and
Control
of the
the
Secretary
projects,
practices
control
and
and
program
up-
River.
15
16
Section
1]
specified
18
that
19
River.
203,
under
irrigation
may warrant
Tit)e
and
study,
II defines
diffuse
including
source
USDA
responsibilities
control
the Virgin
units
River
along
Basin
on
with
of the
other
areas
Colorado
20
21
In this
22
ing
23
implementing
24
25
through
report,
USDA
improvement
the
presents
of onfarm
improvements.
alternative
irrigation
plans
for
efficiency
reducing
and
a plan
salt
for
load-
2
1
This
study
corresponds
2
set
forth
3
and
is coordinated
4
the area.
to the
in the Colorado
with
River
primary
Basin
studies
objective
Salinity
'of other
of salinity
Contro)
federal,
Act
state
control
(Public
and
local
Law
as.
93-3:~O)
agencies
'in
5
6
Salinity
control
7
the
8
Standards
for
9
Council.
The Act
10
Economic
11
the Nation1s
12
the
Environmental
contributes
Quality
Plann~ng
Development
output
EQ and
(EQ) objective
Water
also
to the water
the
(ED) objective.
of goods
ED objectives
and
in this
published
By reducing
services
will
in the
aspects
Principles
of
and
by the U.S.
Water
Resources
that will
be made
to the
contribution
study
improvement
as described
Resources,
recognizes
quality
salt
loading
be increased.
the value
Components
of
of
are:
13
14
Environmental
15
sediment
16
1ife
Quality
and salt
load
lEQ) - Improve
to the Colorado
water
River
quality
and
by reducing
enhance
fish
the
and wild-
resources.
17
18
Economic
19
production
20
salinity
Development
by improved
(ED) - Increase
irrigation
the
efficiency
efficiency
and
of agricultural
reduced
downstream
damages.
21
22
The
significant
effects
23
three
24
and Social
Well-Being.
25
for tables
displaying
accounts.
These
of the alternative
include
See
Economic
Development,
the Alternative
the effects
plans
Plans
of planned
'.;.'~C
3
are
displayed
Environmental
section
alternatives.
of this
in
Quality,
report
1
2
The objective
mentatien
3 fecus
4
plan
ef the
salinity
of the
planning
of actien
pl.an is
and .erosien
effert
to. accemplish
to. reduce
salt
is
the
to. fennulate
program
discharges
from irrigated
an acceptable
ebjectives.
The primary
to. Celerade
and ether
private
imple-
River
by centrolling
lands.
5
6
The results
of this
7
on LaVerki.n Springs
8
Sa 1i n fty
USDA study
and the
have been coerdinated
Lewer Virgin
Ri ver
Units
with
through"
WPRS planning
the
Interagency
Cont ro 1 Advi so.ry Corrrnittee.
9
10
Public
Invelvement
Process
11
12
The Local
13
discussien
14
and directed
15
on July
16
pu~lic
Interagency
ef study
10,
the
public
Control
Las Vegas.
Priar
Team for
This
their
input.
study
cammittee
to. organizatian
local
pravi ded a ferum fer
coordinated
program.
to. obtai,n
Planning
Cerrrnittee
and proposals,
infonnatio.n
were held
17 ,WPRS's Interagency
18
findings
1979 in
meetings
Salinity
was arganized
af the
Meetings
Lawer Virgin
activities
corrrnittee,
were held
River
with
Unit Salinity
Study.
19
".
20
21
Follawing
Salinity
Cantrol
is
a list
af agencies
participating
Carrmittee:
22
23
24
25
4
on the
Lacal
Interagency"
U.S.
Department
of Agriculture
Mohave
Agricultural
Stabilization
and
Conservation
Service
Forest Service
Science and Education
Administration-
Mohave County
Board
Supervi sOY'S.
Clark
Environmental
U.S.
Department
Protection
of the
Bureau of Land Managerr:ent
Fish and Wildlife Service
State
of Arizonal/
State
of Nevada
County,
of
Nevada
Agency
Interior
Geological
Survey.
Water and Power Resources
Arizona
Littlefield-Hurricane
Valley
Natural Resources
Conservation
District
Agricultural
Research
Soil Conservation
Service
U.S.
County,
Comprehensive
Conservation
Planning
District
Public
Department
Town
Service
Works
Boards
- Clark
County,
flevad
Coun~~,
Arizo
Bunkerville
~:esquite
Town
Board
- Mohave
Littlefield
Department of Wildlife
Division of Colorado River Resources
Division of Water Resources
Irrigation
Cooperative
Extension
Service
Desert Research
Institute
Division of Environmental
Protection
Eastside
Westside
Irrigation
Companys,
Irrigation
Irrigation
Companys,
Litt"efield,
Company
Company
Nevada·
State Of UtarJJ
Bunkerville
Irrigation Company
Mesquite
Irrigation Company
Riverside
Irrigation Group
1I
Participation
by requested
revievi of this
5
draft
report.
The Soil
from
Conservation
the USDI,
consultation
dated
of 1978,
Control
May
threatened
was
directed
Area
Office
Fish
Service
Program
for Virgin
may
all
been
Service
for this
1981
inquiry
was
in Boise,
State
informed
directed
study
Act,
1979,
7
and
Basin
endangered
Informal
consultation
California
was
directed
to the Sacramento,
to the
29,
Section
River
and listed
Sacramento,
correspondence
March
in correspondence
in the area.
Service's
telephone
Species
of the Colorado
of the proposed
be present
correspondence
Office
Unit
dated
of formal
the Endangered
and Wildlife
and Wildlife
of the Nevada
have
Fish
in a letter
initiation
River
a list
that
In an April
Members
Water
species
further
Ecological
The
provided
Subsequently
office.
Service,
for the Virgin
to the
that
requested
by PL 95-632,
Study.
11, 1979
and
office.
Fish. and Wildlife
as required
Amendments
Salinity
Service
USDI,
Fish
area
to
California
and Wildlife'
Idaho.
Coordinating
of this
Valley.
6
Committee
proposed
for
salinity
the Rural
control
Clean
program
1
FOREWORD
2
3
Virgin
Valley
4 to Lake ~ad
Subevaluation
on the
5 cover.
Virgin
6 where
irrigation
Colorado
Valley
River..
Subevaluati6n
and erosion
7 study,
alternative
8 of the
plans
Unit,
are
solutions
on reducing
a portion
See the
map on the
diffuse
sources
loading
River
inside
Unit was identified
were identified
salt
of Virgin
drains
of the
front
as a problem
of salinity.
and estimates
to Colorado
Unit,
area
During
the
were made of effects
River.
9
10
An interdisciplinary
11
The "USDA Study
12
Soi 1 Conservati
13
ment",
14
references.
15
National
Plan
team
for
the
carried
Virgin
out the
River
study
Unit",
and prepared
revised
on Servi ce (SCS) publ i cati on "Gui de for
March 1977 along
with
Information
SCS environmental
relating
Environmental
Policy
policy
to evaluati-ons
Act of 1969 is
for
in the
the
August
report:.
1978,
Envi ronmental
and the
Assess-·
and 7 CFR-650 were
compliance
with
the
appendices.
16
17"
18
19
Contributions
ledged.
Nevada
assessment.
from other
Department
The United
•..
20
Resources
Service
21
provi ded
stream
22
Clark
23
wi de. water
County
Federal
and State
of Wildlife
States
information
C'epartment
(WPRS) and Geological
gage
data
Conservation
management
alid other
District's
pl anning
of Nevada
informati
onfarm
reports
25
i
(USDI),
irrigation
for
Other
Water
input
acknow-
and POWE!r
reports,
incl uded the
inventories
Cl ark
are
biological
(USGS) published
on.
prepared
24
was used for
of Interior
Survey
agencies
County,
and area··
Nevada.
1
The USDA Science and Education Administration-Agricultural
2
Salinity Laboratory, Riverside, California, outlined study needs, provided
3
consultative assistance and analyzed water quality samples.
4
in interpreting laboratory test results and reviewing results of the study was
5
most helpful.
6
7
8
9
10
11
12
13
14
15
16
1]
18
19
20
21
.22
:23
24
Research (SEA-A~
..
ii
Their assistance
1
SUMMARY
2
3
Virgin
Valley
of the
Subevaluation
Virgin
River
Unit,
4
study
Unit
5
The USDA study
6
of Colorado
River
from irrigation
Virgin
River
flows
identified
Nevada,
in-Arizona,
alternative
is
Nevada
solutions
and other
the
second
part
and Utah.
for
salt
1.,
See Figure
reducing
diffuse
of a USDA
salt
loading
sources.
7
8
9
River.
Upstream
through
Virgin
from Littlefield,
10
Above the
narrows
is
the St.
11
bei n g studi ed and reported
Valley
Arizona,
George
into
the
Lake Mead on the
river
agricultural
flows
Colorado
through
area
in Utah.
is
4,625 with
a narrO\lls.
This
area
is
on separately.
12
13
The total
14
irrigated
15
The surface
16
ar~a
irrigated
acreage
by surfacerethods
are
irrigated
17 .Bunkerville,
being
irrigated
19
tribute
to the
20
portion
were not
and the
Arizona,
Nevada,
18
and 1,099
acreage
Littlefield,'
874 acres;
with
sprinkler
salinity
in Virgin
Valley
acres
by sprinkler
agricultural
438 acres;
and Riverside,
and drip
of Virgin
Nevada,
systems.
in the
1,820
does not
and irrigation
study
acres;
Nevada 394 acres.
systems
River
arid drip
communities
Mesquite,
3,526 acres
The area
significantly
improvements
confor
this
evaluated.
21
22
The existing
23
were analyzed:
24
benefits
25
page i x.
condition
Future
and costs
and three
Without
associated
Program,
with
the
alternative
Alternative
alternatives
iii
levels
of salt
reduction
1, and Alternative
are
summarized
2.
in Table
The
2,
E
V
A
D
A
UTAH
Virgin Valley
Study Area
.Ii'
George
---
------
Littlefield
Lincoln County
.~
0""
Clark County
~'Y
.- I
Bunkerville
5
I
~~e#
j(
<'\,0
\),.0
.y~
e~
~>
"$'
N
A
~I
R
A
Z
D
o
A
N
A
5
~ mil es
0
Scale
I
LEGEND
........
~
Figure
River
1
....--...~
•••.-- Interrn;ttent Stream
'--~
_
1-)5
Hydrologic
Boundary
Interstate
Highway
LOCATION
Virgin
IISCA-SCi
Valley Subevaluation Unit
Arizona, Nevada, Utah
of the Vlrgln
iv
Colorado
t1AP
River
River Unft
Basin Salinfty
Control
Progl
1
Virgin
River contributes
an average
2 si x mi11i on tons of sediment
3 37,200 tons of salt
4 (1) improving
5 tons);
of 426,000 tons of salt
the irrigation
(2) improving
6 irrigation
efficiency
7 reduction
of erosion
delivery
in this
subeva1uation
system to reduce
water managerrent by increasing
from 44 to 62 percent
by irrigation
8 are shown in Alternative
M annual reducti on 0 f
to Lake Mead each ye ar.
could be accomplished
2,
unit
canal seepage
the average
(30,300
and nearly
tons)
management (100 tons).
by:
(6,800
onfarm
and (3) a minor
These components
the Recommended Plan.
9
10
Implementation
oftheR-ecommended
11
semi automated onfarm irrigation
12
The present
annual operation
Plan (Alternative
2) would require
systems with a construction
and maintenance
cost of $1,937,000.
cost would increase
from $5,000
·3<':~'I.~_'~''r.f-C!
13
to $35,309-because
14
needed for the automated
15 i.ncreased
of labor,
efficiency
additional
systems.
maintenance
These increased
and replacement
costs
costs
wou1d be offset
by
of crop production.
16
17
The existing
canal
and lateral
distribution
18
need improvement to reduce excessive
19
the off-farm
20
about $10,000 is spent
21
maintenance
22
system improvements
distribution
systems
annually
and replacement
seepage.
is estimated
for operation
costs
would increase
Total
installation
to total
and maintenance.
to $23,400 annually.
24
25
v
Valley
costs
$733.000.
of the recommended off-farm
23
•
systems in Virgin
of
Presently,
Operation,
distribution
1
Installation
2 assistance
3 tenance
cost
totals
for Alternative
$3,100,000.
to be $479,800
$430,000 for technical
Total program cost including
and repl acement costs
4 estimated
2 including
and followup
operation,
techni cal assi stance
annually ·over a 25-year
evaluation
main-
added
is
period.
5
6
Downstream and onfarm annual benefits
7 total
$2,172,200
8 $2,052,400
9 tration
following
based on a reduction
savings
12 (2,172,200
accruing
of 3.97 milligrams
for a 25-year
Total
period
installation
per liter
in salt
Damnear Yuma, Arizona.
from Alternative
of $50,000.
during
Downstream annual benefits
in the Colorado River at Imperial
10 onfarm benefits
11 labor
installation.
increase
2 are $119,800.
program benefits
and $1,062,000
are
concenAnnual
This includes
are $3,234,200
during
and
annually
the 10-year
installation
13 period).
14
15
Impl ementati on of Al ternati
16 federal
cost-share
assistance
ve 2 coul d require
to assure
17 'Users woul d fumi sh the remaining
18 and replacement
19
-a higher
level
20 Virgin Valley.
21 necessary
costs.
Existing
assistance
a 75 percent
farmer participation.
cost plus annual operation,
See Table 1.
of cost-share
adequate
at least
local
for the canal
maintenance,
indebtedness
may require
system improvements
Proper water management "as well as improved systems
to achieve
the salinity
control
objectives.
vi
Land
are
in
]
1
TABLE 1.
ANNUALLEVEL OF FUNDINGFOR 1Q-YEAR INSTALLATIONPERIOD,
ALTERNATIVE2, VIRGIN VALLEYSUBEVALUATIONUNIT, ARIZONA, NEVADA
2
Li
T~
3
Annual
$66,700
Construction
~:,~,',.'
Construction1/
Technical
Assistance
$
$
5
\EI
~
6
7
200,300
~J
-:~
----.--Annual
OM&R
Total
Total
74,200
317,500
Annual
Other
Funding
$
$7,500
Funding
- - - - - - - - --
4 - - -- -- -
il
1;
Federal
Total
$
43,000
243,300
8
1/
JI;
'~I
~
[I
~M
!ts
1980 Prices
- Based on 75 percent
federal
cost-sharing
irrigated
lands in this subeva1uation
unit.
9
10
Table
2 provides
11
Table
3 is
12
resource
13
The environrrental
14
effects
to pertinent
15
salinity
-control
16
ditions
a summary of costs,
a summary of composite
uses.
Environmental
environrrental
evaluation
evaluation
benefits
results
and physical
ratings
inventory
in Table
assistance.
for
effects,
while
alternative
worksheets
3 show
No Utah
are
no adverse
in Appendix
A.
composite
nl
:J.
~
\.~
r'
,J,
~'
t' ..,
17 -water
will
will
resource
rreasures.
occur
enter
with
uses
Slight
studied
which
overall
improvement
implementation
of the
result
from the
proposed
in some resource
recomrrended
plan.
con-
Better
quality
Lake Mead.
18
~
19
[I
l~
tII
Physical
20
for
21
in thi s study
22
resources
23
lTEasures.
24
field
25
Thi s represents
Uni
salinity
land
treatment
control
will
and is
area.
not
not
be adversely
and delivery
about
in Virgin
included
Uni que cu1 tural,
About 10 acres
ditches
of rangeland
in this
hi stori
disturbed
of pa1ustine
canals
0.1 percent
t.
vi i
will
plan.
ca1,
by the
wetland
total
could
There
not
installation
upland
wetl and area
land
or natural
of proposed
adjacent
to
be justified
is no forest
archeo1 ogi ca1,
habitat
be converted
of the
Valley
to the
wildlife
in the
unlined
habitat.
Subeval uati on
1
Monitoring
and evaluation
2 resources
affected
3 to assess
impacts
4 to the
Vi rgin
by the
of irrigation
pl anned
of proposed
improvements
salinity
control
Ri ver.
5
6
7
8
9
10
11
12
13
14
15
16
17 ~
18
19
•..
20
21
22
23
24
25
vi i i
water
will
management
and related
be ini ti tated
measures
upon salt
or expanded
contributions
TABLE
2.
SUMMARY OF COSTS, BENEFITS
VIRGIN VALLEY SUBEVALUATION
Item
AND PHYSICAL
EFFECTS OF ALTERNATIVE
UNIT, ARIZONA,
NEVADA, UTAH
Future
Unit
Without
PLANS
'\
~L TERN"HIVES
.
2JJ .
11..
COST-( O-N-E-T-r-j"l-E
)-:
Onfarm
Construction
Deliver~stem
Total
Technical
~OOO
Construction
$1,000
300.0
510.4
2,670.0
90.0
182.6
430.0
$1,000
390.0
693.0
3,100.0
$1,000
34.6
61. 5
$1,000
$1,000
33.8
!LOOO
15.0
31. 4
13.5
$1,000
94.5
126.8
1.4
~OOO
14.6
861.9
184.5
$1 ,000
16.0
1,046.4
Assistance
$1 ,000
(10 Yrs)
Installation
COST1/
Installation1!
Operation,
Maintenance
Total
18.0
53.4
137.9
13.5
13.5
479.8
BENEFITS:
$1,000
Salinity
Reduction
(Downstream)~/
Increased
Efficiency
of Crop Production
Subtotal
Benefits
During
Installation
$1,000
$1, 000
NET BENEFITS:
PHYSICAL
119.8
2,172.2
_ 1 , 062".o..~
23,7
1,558.0
3,234.2
-70.8
1,431.2
2,754,4
EFFECTS
-200
tons/yr
mg/1
Salt Load Reduction
6/
Salt Concentration
ReductionNet Annual Increase of Water in
River
2,052J~
511.6
7.8
~OOO
(10 Yrs)
Total
ANNUAL
275.0
and
Replacement
(OM&R)
5
Interest During Construction-!
FoTlowup Technical
Assistance
(25 Yrs)
ANNUAL
1,937.0
733.0
Construction
Total
ANNUAL
466.0
44.4
200.0
100.0
$1 ,000
ac- ft
System
37,000
15,100
1. 67
0.003
3,97
200
800
800
8
16
16
40
40
.~
Wetland
n
Habitat
Upland
Habitat
Onfarm
Increase
Requirement
fl-
Lost
Gained
in Fossil
(Average
;;
..\l:.ernati'le
1
Use
;/
Alternative
2 -
imOr'ove canai,
i?:dst.ing
31
Ccm:ound
~/
SI
July
1980 ~rice
~dse,
25-year
1 re
Inc1uces
G~"". jri:.er~st
on O~,'1. and
~/
Coiorado
percolation
I]
l~
in::eresc
River
at
:it se'Ie ..'
:.nceridi
canai
lateral
(lna
oicM
irrigation
,.1,nd three-eight,:"lS
i
Jam,
systems'
pioeline
and
near
lateral
mir,or
',>iit:"1
sfstem
ga1/yr
30
n~aai""s,
and onfarm
cnfari'il irrigation
imorove
irrigation
710
480
3jsterns.
,'·lini/i1um deo:o
sys~ems.
efficiency.
oercent
and 1.'1tzrest
at
interest
QM :he
on eX:Jend1t~res
S2v-en and
construction
three-ei
Co3S::
'(urna, Arizona.
n
;~
TI
8
Fuel
Annual
and
ac-value
ac-value
i
X .
equdl
arr.aun::s)
roc:"'s ;Jercent,
nC'.Jrred
duri."g
dUr'"ing
the
:,"",e :sn
instailation
yedr
insta1iation
~eri.'Jc.
;.enoC.
TABLE
SUjvlMARY RATINGSli
3.
ENVIRONMENTAL
VIRGIN
VALLEY
SUBEVALUATION
ARIZONA,
2I
lanninq
EVALUATION
NEVADA,
UTAH
323
33
32 43231 Without
I
Future
Alternatives
3
Compos ite Rati ng
1/
-
The rating scale is from 1 to 5:
1, unsuited;
neutral; 4, good; and 5, excellent.
Note:
'<:'C
For detailed
UNIT
environmental
evaluation
x
data,
Future
3
2, poor;
Conditions
3
3, fair
~ee Appendix
A.
3
or