Re: Response to Comments on the Proposed Salt Lake Valley Ground-Water Management Plan
Dear Salt Lake Valley Ground-Water User:
The Division of Water Rights (division) appreciates the time and effort expended by the water users in reviewing the Proposed Salt Lake Valley Ground-Water Management Plan (the plan). The comments received by the division are a useful critique of the various provisions and underlying assumptions in the plan. Since some of the issues raised by individual entities may be of interest to others, and similar comments were made by several ground-water users, we have decided to provide a general response to the comments. The purpose of this response is to 1) clarify certain aspects of the plan, 2) respond to concerns expressed by the water users in the valley, and 3) stimulate continued critical thinking of the water management issue in the valley. The state engineer’s response to the comments submitted are set forth below.
1) Many water users are concerned with the assumptions used to calculate the potential withdrawals incorporated in the priority list. They feel the plan will reduce their water rights in accordance with the assumptions.
The potential withdrawals listed in the priority list are only intended to represent an approximation of the annual diversion for each water right within the Salt Lake Valley. The assumptions used to compile the priority list in no way restrict the amount of water that can be diverted under any given water right or provide a legal basis for forfeiture of claim to water not beneficially used. If all underground water rights were evaluated at their maximum flow rate, there would be about one million acre-feet per year of “paper water” in the Salt Lake Valley ground-water basin. However, the actual withdrawals amount to much less. We recognize that the actual withdrawals under any particular water right may be more or less than what is shown on the list, but collectively, the potential withdrawals appear to be reasonable estimates.
Under the proposed plan, the potential withdrawal estimates set forth in the priority list will be used to determine if a management square exceeds the maximum withdrawal limit of 12,000 acre-feet east of the Jordan River or 2,000 acre-feet west of the Jordan River. These estimates will be considered in the evaluation of change applications.
The priority list is based on an assumption that the “potential diversion” for any given water right is evenly distributed to all points of diversion listed under that water right. This is a way to estimate the areal distribution of withdrawals for water rights or groups of water rights with multiple points of diversion. The division recognizes that this pattern of withdrawals does not necessarily reflect actual withdrawal patterns and does not propose to require any particular distribution of withdrawals to various points of diversion associated with a water right.
2) Several water users have noted various errors and omissions in
the priority list.
While every effort is made to make the list accurate, there are inevitably
errors and omissions. The majority of these relate to water rights for
which a change application has been approved. The division is in
the process of updating and correcting errors associated with the priority
list. However, the overall distribution and quantity of potential
withdrawals throughout the valley are not expected to change significantly.
3) Several respondents have indicated a need to incorporate provisions in the plan to manage Aquifer Storage Recovery (ASR) programs.
The division is supportive of ground-water recharge and recovery projects. These projects will be managed separately from the plan and each proposal evaluated upon its own merits. No ASR injections or withdrawals will count toward any of the localized or regional ground-water withdrawal limits set forth in the plan.
4) Several water users have indicated that it would be beneficial to provide some flexibility within the plan for ground-water remediation projects.
The division agrees that remediation projects should be given special consideration if they are shown to be in the best public interest. Each proposed remediation project will be evaluated on its own merits and potential adverse impacts on third parties will need to be addressed.
5) Several respondents have suggested that the plan remain flexible in lieu of future scientific studies and data relating to the hydrogeology of Salt Lake Valley.
Although the division believes that the plan is based on the best and most recent scientific data available, new and relevant data which may refine ground-water characteristics of the valley, are welcome. The division will consider updating the plan as significant new data and information becomes available. Any such modifications will be done in consultation with Salt Lake Valley water users in future drafts at a public meeting.
6) Several comments pertain to local interference between wells.
The 12-foot drawdown rule set forth in this plan was carried over from the Interim Ground-water Management Plan implemented in 1991. The rule applies only to wells drilled after 1991. This guideline was added to the Interim Plan at the request of water users, and is intended to apply to interference caused by a single well and not to the cumulative effects of multiple wells. The intent of the provision is to give some general guideline as to the degree of drawdown from a single well the water users will accept as being reasonable. Whether or not local interference occurs in any particular instance, or whether pumping adjustments are made, must be determined at the time the application is before the state engineer. If the water users do not want this provision, the state engineer will consider deleting or modifying it in future drafts of the management plan.
7) Some entities are concerned about the criteria that would be used by the division to establish an annual diversion volume since most of the water rights within the valley are currently based only on a flow rate.
Article 2.3 (Proof of Appropriation/Change), of the draft plan indicates that “in conjunction with all proofs of appropriation and proofs of change, the state engineer shall require that the total volume of water to be certified has in fact been developed and placed to beneficial use.” This statement merely reflects what the proof policy for most water rights has been for years. The division will quantify a given water right for certification based on its beneficial use. The owner of a water right must show proof that a certain volume of water has, in fact, been put to beneficial use. The flow rate will remain the maximum flow rate while the volume limitation will be the maximum annual amount that has been put to beneficial use as shown by the proof. This volume limitation applies to approved water rights in Salt Lake Valley as they are certificated.
8) A number of entities have addressed the issue of extensions of time on existing approved applications. Several water users are concerned about holding applications to meet future water demands.
The state engineer is aware of the demands placed on public water supply systems to meet future growth. The question becomes what is a reasonable period of time from when an application is approved and when the water is developed and placed to beneficial use? Is 20 years reasonable? Perhaps 30 years in some cases. In Salt Lake Valley there are significant quantities of water covered by approved applications that are approaching 50 years. The ground-water basin is over appropriated and if these water rights are developed, it has the potential to displace water users who have already developed the water and are using it under a later priority water right.
9) A general area of concern about the plan is the underlying hydrologic data on which the plan is based. The purpose of this section is to address some of the specific concerns.
a) What are the details of the water budget?
Much of the hydrologic data for the plan was taken from the USGS Technical Publications 110-A, 110-B, 110-C, & 110-D and from the associated ground-water flow model. (Copies of these reports were made available at the public meeting. Copies may be obtained at the DNR Bookstore located at 1594 West North Temple or on the division’s web page) The USGS ground-water flow model was used to modify Table 1 of Technical Publication 110-C to come up with the water budget shown below.
Recharge (in af/yr) from:
| Consolidated Rock | 135,000 |
| Irrigated fields, lawns, and gardens | 41,000 |
| Precipitation | 67,000 |
| Canals | 30,000 |
| Streams and channel fill | 16,000 |
| Underflow at Jordan Narrows | 2,500 |
| Jordan River and tributaries | 2,000 |
| Total | 294,000 |
Discharge (in af/yr) to:
| Jordan River and tributaries | 82,000 |
| Wells | 165,000 |
| ET | 29,000 |
| Drains | 7,600 |
| GSL | 1,300 |
| Canals | 9,200 |
| Total | 294,000 |
b) The actual amount of aquifer recharge from consolidated rock may be different from what current data and analysis shows.
That point is duly acknowledged and the division is interested in ongoing or future studies which may present more accurate data on this subject. However, the division believes that a different estimate of the amount of bedrock recharge will not seriously impact the amount of water available for underground withdrawal. Since the above budget is based on a calibrated ground-water flow model, a change to the recharge values will most likely be reflected as a change in other budget components in order for the model to remain calibrated. The budget components most likely affected will be evapotranspiration and river leakage which also possess a certain amount of uncertainty.
c) Various comments refer to the withdrawal limits outlined for the regions or sub-regions in the proposed plan.
Eastern Region
The limit of 95,000 afy for the Eastern Region is considered to be
the “safe yield” based on prevention of water quality degradation.
Simulations show that water moves from the west side of the Jordan River
to the east side when withdrawals on the east side exceed about 95,000
afy. Since water from the west side is generally higher in total
dissolved solids, the quality of the water on the east side would potentially
be degraded by a change in the hydraulic gradient caused by excessive withdrawals.
Eastern Sub-Region
The primary reason for creating the sub-region is to allow for additional
pumping on the east side which is not in the sub-region. Although
the majority of withdrawals from the principal aquifer occur within the
sub-region, recharge is distributed more evenly throughout the entire eastern
portion of the valley. The designation of the sub-region will allow
for additional pumping to occur in other areas of the Eastern Region where
unused water is available.
Eastern Region Management Squares
The 12,000 afy limit is complementary to the regional and sub-regional
withdrawal limits. Its main purpose is also to protect the quality
of the water on the east side of the Jordan River. Ground-water modeling
simulations have shown that high withdrawals in a relatively small area
will potentially allow water on the west side of the Jordan River, which
is generally of poorer quality, to migrate under the river into the capture
zones of wells on the east side. The proposed limit of 12,000 afy
per management square is the maximum level of withdrawals that model simulations
have indicated will not create a localized gradient reversal and subsequent
quality degradation.
Western Region
There is some concern that the west side of the valley cannot support
the suggested limit of 70,000 afy of withdrawal, and that it did not receive
a proportionate amount of recharge when compared to the Eastern Region’s
proposed withdrawal limit. Studies show that recharge from fractured,
consolidated rock on the west side is less than 70,000 afy and proportionately
less than the amount of recharge in the Eastern Region. However,
the Western Region receives water from several other sources such as precipitation,
seepage from canals, seepage from irrigated fields, lawns, and gardens,
and from underflow from the Eastern Region. The state engineer may
consider modifying the 70,000 afy limit or providing additional guidelines
to ensure an appropriate distribution of withdrawals in the Western Region.
Western Region Management Squares
The limit of 2,000 afy for management squares in the Western Region
was proposed to limit changes into areas with water rights with large
amounts of potential withdrawals. Additionally, this will help to
protect the water rights of those with existing, productive wells.
There is no proposed limit on the actual withdrawals for the management
squares in the Western Region. The total annual withdrawal will be limited
to the amount that can be legally withdrawn under the existing water rights
currently located in that management square.
Another concern with the system of management squares, is that the aquifer properties are quite variable and management areas should reflect areas of the aquifer with similar hydrologic properties. This is an important and relevant concept, but difficult to implement because there are no clear-cut hydrologic lines. Certainly, there are areas of the aquifer with favorable hydraulic conductivity or relatively good water quality. However, drawing an equitable and defendable line based on aquifer properties has proven to be very difficult in the past -- especially with water users who are located very close to one side of the line or the other.
The state engineer is examining the feasibility of modifying the 2,000 afy limit in areas that appear to be able to safely support substantially more withdrawals. He will also continue to evaluate the hydrogeologic conditions on the west side and will consider modifying the management approach in that region in order to establish an equitable and agreeable ground-water management strategy.
d) There are both concern and agreement with the designation of the Jordan River as a regional boundary.
The main concern is that the Jordan River is not a true hydrologic ground-water divide so that some wells in the Western Region may be receiving water from the east side of the valley while some wells in the Eastern Region may be receiving water from the west side of the valley. An examination of hydrologic data from the 1960's -- before the ground-water system was significantly stressed -- shows that the Jordan River has historically acted as a hydrologic divide. However, recent ground-water models, water quality maps, and other hydrologic data indicate that the ground-water divide does not correspond exactly with the Jordan River. In the southern part of the valley (Sandy, Midvale, Murray) the ground-water divide appears to be slightly east of the Jordan River. Incidentally, this is why the water quality on the east side is affected, or has the potential to be affected, in that area. In the northern part of the valley (West Valley City, Salt Lake City) the ground-water divide appears to be just west of the Jordan River. These occurrences can most likely be attributed to heavier pumping at or near the affected areas over the last 30 years. Despite these indications, though, it is still advantageous to designate the Jordan River as a regional boundary because it is an easily defined landmark, and reasonable approximation of the hydrologic divide.
The division would like to thank those who have participated in the
review of the proposed update to the ground-water management plan
for the Salt Lake Valley. It has come to our attention that several
entities with a stake in Salt Lake Valley ground-water did not get an opportunity
to submit comments or were not aware of the existence of the draft plan.
The division is developing a new draft of the plan and hopes to have another
public meeting within the next couple of months. Opportunities for
further comment will be provided at that time.
Robert L. Morgan, P.E.
State Engineer