Water Court Weld County, State of
Colorado Court Address: 901 9th Avenue,
Greeley, CO
80631 Phone Number
:(970)351-7300
CONCERNING THE
APPLICATION FOR WATER RIGHTS OF: THE PARK COUNTY
SPORTSMEN’S RANCH, Applicant IN PARK COUNTY |
COURT USE ONLYCase Number: 96 CW
14 Water Division No.
1 |
| |
ORDER DISMISSING APPLICATIONC.R.C.P. Rule 41(b)(1) |
I. Applicable Standard for ruling on Rule
41(1)(b) motions.
Where,
as here, the court is the trier of fact, the court must weigh all the evidence,
determine questions of credibility, and draw all reasonable inferences
regardless of which party such inferences may favor. The standard is not whether
the plaintiff established a prima facie case, but whether judgment in favor of
defendant is justified on the evidence presented. Teodonno v. Bachman, 158 Colo. 1(1965);
Campbell vs. Commercial Credit Plan,
Inc., 670 P.2d 813 (Colo. App. 1983).
II. Theory of the
Case.
The Applicant (PCSR)
proposes to create storage by withdrawing 140,000 acre-feet (AF) from the South
Park Formation, a saturated aquifer consisting to two strata that are separated,
for most of the length of the formation, by a relatively impermeable
stratum. The resulting cone of
depletion will constitute the “storage vessel.” The withdrawn water will be discharged
into the South Platte River stream system for delivery to the City of Aurora
under an existing contract between the City of Aurora and PCSR.
PCSR proposes to store
water, during times that the South Platte River system is free, by diverting
excess stream flows into recharge reservoirs and ditch fields that will be
located upon the upper surface of the South Park Formation. The water thus diverted and stored will
percolate into the underlying aquifer, recharging it and reducing the volume of
the depletion cone that has resulted from PCSR’s pumping. PCSR claims the amount of this recharge
as the actual volume of the water it will store.
The South Park Formation is
tributary to the South Platte River system. PCSR has no water rights in the system,
other than the 1996 rights that it seeks in this application; hence, its pumping
from the aquifer constitutes an out-of-priority diversion that will eventually
result in depletions to the stream system.
PCSR intends to augment these depletions, at times when there is no water
in the surface reservoirs, by pumping additional water from the aquifer for
direct discharge to the stream. It
also intends to claim, as part of its recharge to storage, irrigation run-off,
precipitation and water salvaged as a consequence of the loss of the surface
vegetation. This vegetation will be destroyed as the direct result of PCSR’s
lowering of the water table by its pumping regime.
PCSR will determine the
quantity and timing of depletions by use of the ModFlow computer model to determine
aquifer characteristics that govern the timing and amount of recharge, the
fluctuation in the size of the depletion cone, and timing, location and amount
of depletions to the stream.
The depletion cone will
exist beyond the life of the project, until it is eliminated by recharge from
natural sources, fluctuating in size in tandem with fluctuating precipitation
patterns. Quantification and
timing of recharge, like quantification and timing of stream depletions, depends
on both the validity and reliability of PCSR’s ModFlow computer model. [1]
The admission of scientific
evidence and expert opinion is controlled by C.R.E. Rule 702. People v. Schreck ,
__ P.2d __, (Colo. 2001); Case No. 00 SA105; 2001 Colo., April 23, 2001. In this case, the focus of Rule 702 is
upon the reliability of the Modflow model output and the expert opinion based on
model output. The relevance of such
output and opinion turns upon the usefulness of such evidence to the
court.
The court finds that the
model, itself, is widely used to model aquifer parameters, among other uses, and
that it is capable of producing reliable, relevant results. However, the court concludes that, in
order for computer modeling results to be reliable, and hence relevant, for
predicting the timing and amount of both depletions and recharge, the model must
be operated in a manner that is consistent with accepted modeling
techniques. If the model is
operated in some other manner, there must be sufficient evidence that such other
method produces valid and reliable results.
In this case the techniques
applicable to the operation of a ground-water flow model such as ModFlow are set
forth in the American Society For Testing
And Materials (ATSM) Standard Guide for
Application of a Ground-Water Flow Model to a Site-Specific Problem (ATSM
Guide D-5447)[2],
and Calibrating a Ground-Water Flow
Model Problem (ATSM Guide
D-5981)[3].
The court’s paraphrase of the relevant techniques follows.
The
guide covers the application of a ground-water model to a particular site or problem,
and refers to the application of a mathematical technique to the solution of a
site-specific ground-water problem.
The guide also illustrates the major steps taken in developing a
ground-water flow model to simulate an aquifer system that has been studied in
the field. The guide cautions that
each ground-water model is unique and may require additional procedures in its
development and application. One of
the first major steps is calibration.
Calibration. The
ATSM Guide defines calibration as
the process of refining a model
representation of the hydrogeologic framework to achieve a desired degree
of correspondence between the model simulation and field observations. In practice, model calibration is
frequently accomplished through trial-and-error adjustment of the mode1's
input data to match field observations, and continues until the degree of
correspondence between the model simulation and the observed physical
characteristics is consistent with project objectives. Calibration is evaluated
through analysis of residuals, i.e.,
the difference between the observed value and the simulated value of a given
variable, and is conducted to bring the mean of the residuals close to zero, and
to minimize the standard error[4]
of the residuals. Most
site-specific ground-water flow models must be calibrated prior to use in
predictions. In these cases, calibration is a necessary, but not sufficient,
condition, that must be obtained to have confidence in the model's predictions.
If
it becomes apparent during calibration that there are no realistic values for
the hydraulic properties of the aquifer that will allow the model to reproduce
the calibration targets, then the conceptual model of the site may need to be
revisited, or the construction of the model may need to be revised. In addition, the source and quality of
the data used to establish the calibration targets may need to be reexamined.
Calibration often necessitates
reconstruction of portions of the model, resulting in changes or
refinements in the conceptual model. The modeler then revisits previous steps to
achieve a better representation of the physical
system.
Verification. Calibration
of a ground-water model to a single set of field measurements does not guarantee
a unique solution. In order to reduce the problem of nonuniqueness, the model calculations
may be compared to another set of field observations that represent a different
set of boundary conditions or stresses. This process is referred to in the ATSM
Guide as verification. In model verification, the calibrated
model is used to simulate a different set of aquifer stresses for which field
measurements have been made. The model results are then compared to the field
measurements to assess the degree of correspondence. If the comparison is not
favorable, additional calibration or data collection is required.
Successful verification of the ground-water flow model results in a higher
degree of confidence in model predictions.
Sensitivity
Analysis. The
ATSM is not an inflexible description of techniques for calibrating a
ground-water flow model. Other
techniques may be applied as appropriate and, after due consideration, some of
the techniques herein may be omitted, altered, or enhanced. As an example, a ca1ibrated but unverified model may still
be used to perform predictive simulations when coupled with a careful
sensitivity analysis.
Sensitivity analysis is a quantitative method of determining the
effect of parameter variation on model results. The purpose of a sensitivity
analysis is to quantify the uncertainty in the calibrated model caused by
uncertainty in the modeled values of aquifer parameters. It is a means to identify the model
inputs that have the most influence on model calibration and
predictions. Sensitivity
analysis provides users with an understanding of the level of confidence in
model results and identifies data deficiencies. Sensitivity of a model parameter
is often expressed as the relative rate of change of a selected model
calculation with respect to a given parameter. If a small change in the input
parameter causes a significant change in the output, the model is sensitive to
that parameter.
The
court finds that, as applied in this case, the model generated information that
is not sufficiently reliable to support the experts’ or the court’s reliance on
modeling results, because:
1.
The
model was not calibrated in accordance with accepted
standards.
2.
No sensitivity analysis was
conducted on the model.
3.
The model produced anomalous
results that PCSR’s experts were unable to explain.
4.
The residual error in water
level prediction, in two successive runs on each of 12 wells, ranged between 6’
and 198’.
5.
The residual error between
observed and model-predicted levels for 15 of 33 flowing springs exceeds 1 foot,
and ranges between +46 feet and –26feet.
The absolute residual mean is 14 feet.
6.
PCSR’s expert and model
designer, Dr. Harvey Eastman, recognized and reported the need for additional
data, the need for additional model calibration, the need for explanation of the
anomalous results and the need for further evaluation of the model target data,
before he could defend the admissibility of the model results at trial. PCSR declined to follow Dr. Eastman’s
advice.
7.
An independent peer review
was begun, but not completed.
Accordingly, the court finds
that the Modflow model, as operated
in this case, did not produce results of sufficient reliability to permit a
reasonably accurate determination of either the timing, amount and location of
stream depletion, or timing and amount of aquifer
recharge.
PCSR
proposes to divert from tributaries of the South Platte River, in times of heavy
precipitation when the river is free, and store these diversions in recharge
reservoirs and ditch fields for the purpose of augmenting its out-of-priority
pumping.
As a preliminary matter, a conditional right to pump water that would
injure senior appropriators may not be decreed, except in conjunction with a
plan for augmentation. Fox v. Division
Engineer, 810 P.2d 644, 645 (Colo. 1991);
Bohn v. Kuiper, 195 Colo. 17, 19, 575 P.2d 402, 403 (1978). The South Platte river basin is
substantially over-appropriated. Thornton v. Bijou Irr. Co., 926 P.2d 1,
71, n. 66; Cache La Poudre Water Users Ass'n v. Glacier
View Meadows, 191 Colo. 53, 58, 550 P.2d 288, 292 (1976). Hence, out-of-priority pumping is
presumed to be injurious, and without an approved augmentation plan, PCSR’s
pumping plan cannot be decreed.
In approving an augmentation
plan, the court must consider the depletions from an applicant's proposed use of
water, in quantity and in time; the amount and timing of augmentation water that
will be provided by the applicant; and the existence of injury to vested users.
The plan for augmentation must be sufficient to permit the continuation of
PCSR’s pumping, when curtailment would otherwise be required to meet a valid
senior call. PCSR must provide
replacement water necessary to meet the lawful requirements of a senior diverter
in time and location, and to the extent that the applicant's diversion would
deprive a senior of its lawful entitlement. C.R.S. § 37-92-305(8).
With respect to predicted
depletions, it has been established that 140,000 AF will be withdrawn and must
be replaced, beginning at some indefinite time following the commencement of
pumping, and will vary in an indefinite amount until depletions are setoff by
recharge, creating an equilibrium.
As applied in this case, Modflow does not establish any of the
above variables with specificity, let alone reliability. PCSR’s alternative plan, to establish
depletion and recharge in quantity and time by way of a monitoring program, is
prospective and incapable of predicting depletions until after they have
occurred. It is unrefuted that
depletions to the stream will be lagged with respect to PCSR’s pumping; however,
the timing of the lag has not been determined. The court assumes that the delay between
the commencement of pumping and its effect on the stream system will result in
year-round losses to the stream, whether pumping is seasonal or continual. This assumption is subject to debate,
but is the least troublesome to PCSR in terms of augmenting its depletions. In sum, the court is unable to predict
injurious depletions in either location, quantity or time. On this basis alone, PCSR has not met
its burden.
Availability of water for
augmentation. PCSR proposes to augment
stream depletions with water stored in the aquifer by recharge.
An essential component of an
augmentation plan is the provision for adequate replacement water. Replacement
water may be provided from any water source legally available for use in an
augmentation plan. Williams v. Midway Ranches
Property Owners Ass'n, Inc., 938 P.2d 515, 524 (Colo.
1997).
The predictions of average
annual rainfall, and percentage of years when rainfall exceeds senior calls, are
the subject of controversy both as to methodology and as to resulting
data.
PCSR’s most recent position
is that its system for the collection and storage of water, available when the
river is free, is unnecessary. PCSR
argues that sufficient aquifer recharge will result from precipitation,
irrigation run-off and water salvaged as a consequence of the loss of the
surface vegetation from lands owned by PCSR.
§ 37-92-103(10.5) provides
that:
“Waters
in underground aquifers are not in storage or stored except to the extent waters
in such aquifers are placed there by other than natural means with water to
which the person placing such water in the underground aquifer has a conditional
or decreed right.”
These three above sources
recharge the aquifer a) by natural means, and b) with water that belongs to the
stream system, and for which PCSR has no decreed right. Therefore, PCSR’s most recent position
is untenable, and the viability of its augmentation plan depends upon the
adequacy of its North Branch collection and reservoir recharge
systems.
PCSR’s augmentation plan thus depends
upon the availability of water that it can divert in priority, which in turn
depends upon stream flow dynamics of the various tributaries of the South Platte
river that feed PCSR’s collection system. As a threshold requirement, PCSR must
prove that water is available “in priority, in sufficient quantities, and on
sufficiently frequent occasions to enable it to complete the appropriation with
diligence and within a reasonable time.” In Re Water Rights Of The Bd. of County
Comm’rs, Arapahoe County, 891 P.2d 952, 962 (Colo. 1995). Here, the timing, frequency and quantity
of water available from PCSR’s collection system is critical to the adequacy of
the augmentation plan.
PCSR, through its expert,
Ross Bethel, claims that its collection system will yield an average of 4255
AF/year over and above total senior calling rights. In reaching his opinion on average
yield, Bethel employed a computer modeling program knows as RIBSIM (RIver Basin SImulation Model) which he developed and has
applied in estimating yields in seven different river basins over a twenty-year
period. The validity and
reliability of the model is not disputed.
However, like any computer model, the accuracy of the results depends
upon the accuracy of the data and the validity of the assumptions used by the
modeler.
The Tarryall Creek basin, which supplies PCSR’s North Branch collection
system, consists of Tarryall Creek, and its tributaries Michigan, Jefferson and
Snyder Creeks, and Packer Gulch.
Smaller tributaries include French Creek, a tributary of Michigan Creek;
and, Deadman Gulch and Guernsey Creeks, tributaries to Snyder Creek. Flow
records exist for only Tarryall, Michigan, Jefferson and French creeks, although
there are a number of gages at certain confluences. The existing flow records are of limited
duration, generally for different time periods, and present an insufficient
basis in themselves to estimate average stream flow for the 47-year period
utilized by Bethel and Eastman. For
Tarryall Creek, the records span a 100-month period and were recorded at its
upstream-most gage at Como (Tarcomo gage).
In order to estimate average yield, Bethel first relied on flow records
for the north fork of the South Platte river (North Fork), which drains a basin
adjacent to the Tarryall basin.
These records date from 1943 to the present, and are based upon records
from a gage on Geneva Creek at Grant.
Bethel first compared the North Fork flow data with data from the same
100-month period for which Tarryall Creek recorded flows. From his analysis, Bethel concluded that
the flow at Tarryall Creek averages 28% of the flow in the North Fork.
He then used existing gage
records to correlate Tarryall Creek flows with other streams in basin, e.g.
Michigan and Jefferson Creeks. There is some inherent error in this comparison,
because there are no diversions above the Tarcomo gage, while there are
diversions above the Michigan and Jefferson gages that are not regularly
recorded. Thus, no adjustment for
diversions could be made to the Michigan and Jefferson flows.
Bethel then compared
precipitation records to stream flows within each basin and his hypothesized
precipitation zones within each basin, and derived a factor for the relationship
between stream flow and precipitation in these various zones. For precipitation data, Bethel utilized
the Colorado Climate Center’s climatological map, which shows annual average
precipitation during the period 1950-1980.
He then adjusted the size and location of the precipitation zones to
conform to known flow data, and derived a unit runoff figure of 650
AF/mi.2.
Bethel determined the area
for each stream basin from digitized USGS topographical maps, and calculated the
Tarryall Creek basin to be 23.5 mi.2. Working backwards, he found that the
gaged stream flow yielded a unit runoff figure of 553 AF/mi.2, as
opposed to 650 AF/mi.2 that he had derived from reported average
rainfall. He then adjusted the
reported precipitation to yield model results that were consistent with the
results obtained from measured runoff.
In order to estimate average stream flow in the ungaged basins of Deadman
and Park Gulches, and Guernsey and
Ohler Creeks, he applied the precipitation-runoff relationship.
Bethel first applied
climatological data from adjacent basins, then adjusted this data to reflect
measured flows. For example, he
used data recorded in the French Creek basin, which had been gathered only
during the period 1986-90. He compared estimated flows with recorded flows for
that period, and then adjusted precipitation values so that the estimated flows
matched the measured flows. He
applied the adjusted rainfall figures and the unit runoff figure of 553
AF/mi.2 to the areas of
the ungaged basins, and in this way generated estimates of the average annual
flow in each of the ungaged basins.
He then totalled the flows from each basin to determine total average
annual stream flow in the Tarryall basin.
Based upon Bethel’s experience, and his testimony regarding the
acceptability of the methods he employed, the court concludes that Bethel’s
method for determining average annual stream flows produces reasonable threshold
estimates. However, Bethel did not
validate his results by deriving a precipitation-runoff relationship in the
North Fork basin, or deriving a unit runoff-per-acre figure for the North Fork
basin, for comparison to the results he generated in the Tarryall Creek
basin. Inherent in Bethel’s
assumptions is that precipitation, alone, is responsible for runoff. This assumption ignores other variables
that can affect runoff, such as length-width ratio of a basin, the mean slope of
the basin, the subsurface geology and the nature of the vegetative cover. At a minimum, the relative influence of
these other variables should be assessed in order to determine the degree to
which eliminating them from the model will alter the
results.
In addition, Bethel’s calculation of legally available flows did not
factor out irrigation runoff. Nor
did he adjust for the changing call regime in the South Platte river basin. For example, calls were placed for first
time between 1982 and 1995 including Chatfield Reservoir storage rights, and two
Cheesman storage rights: its first-fill (1993) and second-fill (1995) rights,
four Denver direct flow rights, and four 1976 CWCB minimum stream flow rights on
Tarryall Creek. Hence, Bethel’s
model overestimates average stream flow that is legally available for diversion
by PCSR.
Bethel testified that no range of error determinations for his model results was necessary, and therefore he performed none. As an example of model error, average simulated flows in the Tarryall basin are more than 1100 AF higher than gaged flows. The range in disparity between simulated and gaged flows is about 22,000 AF at its extremes. Hence the court is without sufficient information to estimate best- and worst-case scenarios for Bethel’s predictions. This case appears to be the first instance in which RIBSIM surface flow estimates have been used as input to a ground water model such as ModFlow.
Storage. PCSR’s plan further depends upon
sufficient surface storage to contain the legally available water that is
diverted and applied to aquifer recharge.
PCSR proposes to create five recharge reservoirs with a total capacity of
25,000 AF. 17,000 AF of this
proposed storage is contained in Recharge Reservoir #1, which lies upon BLM
lands. This proposed reservoir
would occupy a basin, the bed of which lies directly upon the upper surface of
the Upper South Park formation; hence, it would be an ideal location for a
recharge reservoir.
The United States claims
that, within the BLM holdings,
there are thousands of acres of wetlands, including fens; that the plant
habitat includes both threatened and endangered plant species; and that there is
no substantial probability that the BLM will grant PCSR access to this
parcel. The BLM was prevented from
presenting evidence on these points because of its untimely Rule 26
disclosures.
Nevertheless, ignoring the
U.S.’s claims as unsupported by evidence, these recharge vessels will serve no
purpose until the South Park Formation is depleted by PCSR’s pumping, and the
cone of depression reaches the vessels[5].
Until then, the stored water will simply increase the natural discharge of the
aquifer into the stream system. The volume of the water that will be stored in
the vessels is at this time so problematic as to be speculative. The amount of water available for
recharge depends upon the relationship between the stream conditions that
immediately preceded the conditions permitting recharge, and the rate of
reservoir loss to the stream[6]. That is, the reservoir volume, at any
given time during which the aquifer remains saturated, can be determined only if
both the rate of discharge to the stream is known, and the volume diverted from
PCSR’s collection system is known.
Hence, the volume of water available for recharge at the point in time
when the cone of depression reaches the recharge vessels requires results
generated by the ModFlow and RIBSIM models.
PCSR assumes that, on the
average, more water will be collected and placed in recharge vessels, under its
1996 priority, than will be withdrawn annually for release to the river. The court accepts, for the limited
purpose of exploring the practicality of this assumption, that 4320 AF will be
annually available to PCSR in the long run, and that PCSR will annually pump
only 2500 AF from the aquifer to meet its contract obligation to Aurora. On average, then, North Branch
collection system will generate about 1800 AF more water that it will withdraw
from the South Park Formation.
The average 1800 AF surplus
is misleading, however. For
example, the court considers three scenarios: a) aquifer recharge is less than
2500 AF/year; b) aquifer recharge equals 2500 AF/year; and, aquifer recharge
exceeds AF/year.
If the recharge rate is less
than the pumping rate, then the South Park Formation depletes at an annual rate
equal to the difference between the two rates. In this scenario, the aquifer will
continue to deplete over the period of pumping, and will not recover until an
indefinite time after pumping ceases.
If the recharge rate equals
or exceeds the pumping rate, then aquifer recharge will vary depending upon the
volume of water legally available to the PCSR collection system. Where the rate of recharge equals the
rate of depletion, in those time periods that depletion caused by pumping
exceeds the volume of available recharge water, depletion to the aquifer will
continue and will not be replaced until after pumping ceases. In sum, the court
concludes that the recharge operation is hydrologically – as opposed to legally
– feasible if and only if the recharge rate provided by the PCSR recharge
facilities exceeds the depletion rate caused by pumping. The certainty that recharge to the
aquifer will be be sufficient to satisfy the legal requirement of PCSR’s plan
depends upon the reliability of both the Modflow and RIBSIM models.
PCSR proposes to withdraw
additional water from the South Park Formation during those periods when
sufficient augmentation water is not available to offset stream depletions. The court concludes that this proposal
is no more than a scheme to augment out-of-priority depletions with additional
out-of-priority pumping, and under the above analysis, exacerbates depletions to
the aquifer and to the South Platte river system.
In summary, the court
concludes that:
1.
The results produced by the
ModFlow groundwater model are
insufficiently reliable as a basis to determine the timing, amount and location
of stream depletions, or to determine the rate of aquifer recharge resulting
from the PCSR recharge facilities.
2.
The results produced by the
RIBSIM surface flow model are
insufficiently reliable as a basis for determining either average stream flow or
legal availability of water in the Tarryall Creek basin. Further, these results overestimate
stream flows that are available to PCSR.
3.
PCSR’s revised Exhibit Z, a set of proposed terms and
conditions that are wholly prospective in their application, does not meet the
statutory requirement that injurious out-of-priority depletions must be
quantified in time, place and location prior to the approval of an augmentation
plan.
Therefore, PCSR has not met
its burden of proof.
The court concludes that
recharging a cone of depletion is not “storage”. PCSR’s out-of-priority pumping will
create a cone of depletion that must be refilled. In the court’s view, replacing such
depletions constitutes augmentation imposed by law, rather than storage. Storage is the introduction of water
into a vessel that was empty to begin with, for later removal by the storing
party. By analogy, borrowing water,
like borrowing money, creates a deficit, not an asset. A payment on an installment loan cannot
be equated with a deposit to savings. PCSR’s scheme begins by creating a water
deficit, adding to that deficit by supplemental pumping when rainfall does not
offset stream depletions. PCSR gambles that sufficient rain will fall, in the
long run, to repay both the deficit created by the initial and supplemental
pumping, thereby restoring the stream system to its normal
condition.
Finally, the beneficial uses
ascribed to PCSR’s claims are interdependent and no claim can survive the
failure of another.
Accordingly, the Application is dismissed.
Ordered by the court, June 1, 2001:
/s/
__________________________
Jonathan W. Hays, Water
Judge
Water Division 1
[1]
It appears that PCSR
has abandoned reliance on the ModFlow
results for predicting depletion and recharge and now proposes to assess them,
after they occur, through a monitoring program.
[2]
Exhibit
P-566
[3] Exhibit P-569
[4]
The
standard error is a statistical measure of the variance in the expected values
of an unknown parameter, e.g., the hydraulic conductivity estimates that are
generated by ModFlow.
[5] For
the purpose of this analysis, the court discounts the fact that PCSR cannot
legally pump without a court-approved augmentation
plan.
[6]
The
court recognizes that the timing and extent of the cone of depression will be
influenced by the volume of stored recharge water at times when the South Park
Formation is saturated, but has omitted this additional uncertainty for the sake
of simplicity.