WSP08301

• File Number: 8273.100.50
• Description: Colorado River Basin Salinity Control - Federal Agency Reports - BOR
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 2/1/1988
• Title: Estimating Economic Impacts of Salinity of the Colorado River - Final Report - February 1988
• Water Supply Pro - Doc Type: Report/Study

28 Estimating Economic Impacts of Salinity...

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Research on these topics, including inter-
views with county agricultural commissioners,
project directors, irrigation district officials,
agricultural scientists, and area farmers have not
developed information that permits quantitative
measures of these types of damages. That is,
most (although not all) of those interviewed
indicate that salinity of irrigation water is one of
the reasons that farmers install tile drains, adopt
expensive farm management practices, and per-
haps shift cropping patterns.

While data on the costs of such practices
often can be estimated, the problem is one of at-
tribution. None of the interviewees, regardless
of their degree of expertise, was willing and able
to estimate the percentage of damage caused
particularly or only by salinity of irrigation water
because several other factors contribute to incur-
ring these expenses. Regrettably, published re-
search on the relative importance of saline
irrigation water versus other causes of these
damages is absent or insufficient to establish a
basis for estimating the amount of damage at-
tributable to salinity.

The authors' fIDdings from the research that
Was possible with the resources of this study are
described briefly below in the hope that they
may contribute toward a future study that might
answer the questions of damage estimation and
attribution.

RemovII at lend tram production.
Interviews revealed a consensus that little or
no land is taken out of crop production because
of salt build-up from irrigation water from the
Colorado River. With proper drainage and
management practices, land can be (and has
been) maintained in salt balance. In fact, salt
poisoning is more likely to occur on idle land.
Land which has never been irrigated can be
reclaimed by standard farm practices and instal-
lation of drain tiles, although some land is just
not suitable for any type of agriculture.

Land is taken out of agricultural production
for a number of reasons that are unrelated to
salt. Some land is turned over to development
of cities and towns. Other land is withdrawn
from production because of surplus-crop farm
programs. Still other land becomes uneconomi-
cal to farm in the current agricultural market.

Addltlonll COlts at extraordlnlry tlrm
mlnlgement prlctlcel.
The farmers of the Lower Colorado River
Basin face a conundsum - a continuing
problem. In order to farm in the desert, one
must irrigate, but irrigation of desert land
requires special techniques, including installation
of artificial dsainage. Further, desert land and
its underlying water tables tend to have limita-
tions which require particular irrigation techni-
ques. Finally, there is insufficient native water in
the Lower Colorado River Basin, so irrigation
water must be imported, and the only available
water for irrigation is the Colorado River which
tends to be slightly saline even in its natural state.

If the costs of installiog artificial drainage
were due only to the salinity of the imported
water, they could be readily estimated and attri-
buted, but this is not the case. For example, in
the Imperial Irrigation District, 40,000 miles of
drain tiles are in place. Tiling, which controls a
brackish water table and reduces the accum-
ulation of salts in the soil profile, started before
World War" and became increasingly common.
since 1950. The farmers in the district are add-
ing additional tile lines between existing lines to
compensate for increasing salinity in previously
drained areas. The estimated cost for the
original tile in place, according to a former
Imperial County Agricultural Commissioner, was
$150 per acre. However, to obtain adequate tile
coverage in 1987 in the Imperial Irrigation Dis-
trict, it was estimated to cost $850 per acre. This
does not include other factors that contribute to
the successful operation of the dsains, such as
plowing or deep tillage. These costs of installing
tiles, and of operations to effectively drain the
soil, clearly can be attributed to salinity, some
portion of which is due to the salinity of the im-
ported irrigation water. However, no scientific
data on this relationship are presently available
and neither the irrigation district managers or
active farmers interviewed are willing or able to
make attribution or distribution of costs among
saline irrigation water. groundwater salinity, soil
structure, or other factors.

Additionally, as one official for the Imperial
Irrigation District describes it, tiling is also a
method of land reclamation - a way to reclaim
the land from the multiple deteriorating factors
of use, climate, groundwater and irrigation
water. Tiling is used to reduce the high saline