UTAH DIVISION OF WATER RIGHTS
PROPOSED GROUND-WATER MANAGEMENT PLAN FOR PAHVANT VALLEY
PROPOSED GROUND-WATER MANAGEMENT PLAN FOR PAHVANT VALLEY
I. BACKGROUND
During the past two years the State Engineer has been reviewing
the ground-water resources in Pahvant Valley. As part of this
process a number of public meetings have been held with the water
users to present information and receive input. To better manage
and administer the ground-water system in the Valley the State
Engineer is proposing to implement a ground-water management
plan. The plan sets forth the guidelines of how the resource
will be administered in the future.
The U.S. Geological Survey conducted a study of the ground-water
resources in Pahvant Valley, in conjunction with the Division of
Water Rights. The study covered the period of time up to 1987
and the report entitled "Ground-Water Hydrology of Pahvant Valley
and Adjacent Areas, Utah" was published in 1990. The State
Engineer has relied upon the data and information contained in
this report and the ground-water model developed as part of the
study to define the extent and characteristics of the ground-water
system in the valley.
The total annual recharge to the ground-water system in Pahvant
Valley is estimated to be about 65,000 acre-feet annually.
Current discharge is over 100,000 acre-feet per year, of which
80,000 acre-feet is withdrawals from wells (1988-92 average).
The State Engineer believes there is a significant overdraft in
the valley. This is also reflected in the long-term water levels
of wells. Based upon these and other factors the State Engineer
believes that the ground-water system needs to be managed to
bring the discharge in line with the average recharge.
A review of the irrigated acreage in Pahvant Valley indicates
that of the total 36,000 acres, about 8,800 acres are being
irrigated without a valid or properly recorded water right. This
issue is very serious and will be addressed first to see if, by
eliminating the illegal acreage, the well withdrawals can be
reduced. Water users have pointed out that there are a number of
uncontrolled flowing wells and they believe they should be
controlled or plugged. These wells generally flow during the
winter months and as the large pumping wells are started in the
spring they cease flowing.
The State Engineer is very aware of the ramifications of the
actions he is proposing under this management plan. In
addressing the overdraft problem we want to take into account the
needs and opinions of the local water users and at the same time
manage the ground-water resource on a long-term safe yield basis.
Before any water user who has obeyed the law is denied water, we
want to take all appropriate measures to insure that no water
user is diverting and using more water than they have a water
right to.
The proposed ground-water management plan has a number of
different elements and it is proposed to implement these elements
in phases. Future actions will be determined by the success of
each phase. The initial phase deals with elimination of any
irrigated acreage which does not have a water right and
controlling wasting wells. The second phase proposes hiring a
water commissioner and metering the withdrawals from wells. If
necessary the final phase would be to limit withdrawals by
distributing water based upon priority.
II. MANAGEMENT PLAN
1. Volume of Withdrawals
The Pahvant Valley ground-water system shall be managed so
the long-term average discharge does not exceed the long-term
safe yield. The withdrawals from wells shall not exceed
60,000 acre-feet per year, as measured over a five year
running average.
2. Appropriation of Water
The valley is closed to all new applications to appropriate
water with one exception. Small domestic well filings for a
maximum of 1.0 acre-foot of water to serve one family, 0.1
acre of lawn/garden, and up to 5 large animals or equivalent
could be approved. Such filings must be located sufficiently
distant from public or private water systems to preclude
service from an existing supply. Generally, a five-year
period is allowed upon approval to develop and prove the
proposed project.
3. Ground-water Districts
The valley has been managed based upon six ground-water
districts since about 1965. It appears that this approach
has worked adequately well to distribute the well
withdrawals somewhat evenly over the entire basin.
See this map.
4. Change Applications
Change applications will be considered and evaluated on
their own individual merits. Change applications which
propose to transfer points of diversion of water from one
management area to another will not be allowed.
5. Survey of Irrigated Acreage
The State Engineer will conduct a survey of irrigated
acreage to determine lands being irrigated without a valid
water right. If lands are suspected of being in violation,
a warning letter will be sent to the owner and/or operator
requesting consultation. If a violation is determined, the
owner and/or operator will be notified immediately to remove
the land from production or secure a valid water right for
said land. If compliance is not attained, legal proceedings
will be initiated in the district court.
6. Wasting Wells
All flowing wells are required to be controlled or sealed
within two years.
7. Water Commissioner and Metering
If withdrawals are not reduced to the 60,000 acre-feet level
as a result of actions taken under paragraphs 5 and 6 above,
the following action is proposed. A water commissioner will
be appointed and all wells diverting more than 10 acre-feet
per year will be required to install pitot access tubes
(These pitot access tubes will allow the discharge from the
well to be measured using a manometer). Water users will be
requested to release their power records and the water
commissioner will make periodic flow measurements. With
this data the volume of water withdrawn will be calculated.
Any water user not willing to release their power records
will be required to install and maintain a flow meter
capable of measuring both the instantaneous flow and the
volume of water withdrawn. The water commissioner will
prepare an annual report and submit it to the water users
and State Engineer outlining the ground-water use in the
valley.
8. Distribution of Water
If it becomes necessary to administer the water rights to
meet the withdrawal limit, the water commissioner will be
instructed to distribute the water based upon priority. In
achieving the withdrawal limit set forth in paragraph 1
above, any reductions will be implemented over several years
to allow water users reasonable time to make operational and
financial adjustments.
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The Division of Water Rights developed a priority list of all
perfected and approved ground-water rights of record in Pahvant
Valley. In compiling this list the potential quantity of water
that can be withdrawn annually (potential withdrawal) under the
individual water rights was estimated. The total estimated
potential withdrawals in the valley is about 140,000 acre-feet.
In using the data from the priority listing a number of factors
must be taken into account. For example, some of the rights
shown may no longer be in use and the water use under many of the
old underground water claims is not clearly defined. Another
factor that needs to be considered is, the potential withdrawals
are only that and the actual quantity of water diverted varies
according to climatic conditions, irrigation method, type of crop
grown, operational costs and many other factors. As a result,
the potential withdrawals shown on the priority list do not
reflect actual withdrawals under each right and caution must be
used in the interpretation of the information. If withdrawals are
limited to 60,000 acre-feet per year, it is not correct to
accumulate the potential withdrawals and assume that all rights
with a priority date later than this will be cut off.