Arkansas River. Folder 2 of 2

Surface Water - Ground Water

interchange in the Arkansas River Valley between the Pueblo and Las Animas gaging stations.

Foreword

Recent developments~in the theory of ground water movements offer the possibility of evaluating the interchange of surface and ground waters in an irrigated river valley. It will be the purpose of this study to apply these methods to the 85 mile reach of the Arkansas River Valley between the Pueblo and Las' Animas gaging stations to determine whether the surface-water ground-water interchanges can be evaluated with the accuracy needed for planning purposes.

Nature of the stUdy

The study covers the 10 year period 1951 to 1960 inclusive. Average values for each month are used as a basis for the study. As a test of adequacy the flow of the river at Las Animas will be computed from the inflows and diversions in the reach. As a beginning the flows of the Arkansas at Pueblo supplemented by the flows of Fountain Creek, Salt Creek and the flows of the st. Charles and Apishipa rivers will be summed. The diversions of the canals in the reach will then be subtracted from these sums and the depletions due to phreatophytes will be accounted for. Finally, the return flows will be adde~ To evaluate these the waters applied to the land each month will first be found. To these will be added the precipitation contributions ffild the consumptive use will then be subtracted to find the amount of water reaching the water table in each month. These waters will

return to the river in a pattern determined by the properties of the aquifer. An extension of the Maasland~developmentis used to determi,ne the amount of return flow appearing in the river each month. 1'he algebraic sum of these factors should be the Las Animas flow.

The estimated flow of the Arkansas River at Las Animas, found in this way, is compared with the observed flow and the closeness of agreement is used to judge the effectiveness of the procedures. The comparison obtained is shown in figure 1. A substantial agree-ment i$ found.

Conclusions

It is concluded that the effects of ground water storage and return can be evaluated with sufficient accuracy so that this factor can be included effectively in operations studies made for planning purposes.

Details of the Computation

Data on the flows of the Arkansas River, Fountain Creek and the st. Charles and Apishipa rivers were obtained from USGS Water Supply paper 173l.~ Records of the flow of Salt creek were

Data on canal diversions were obtained from Volume II of the Comprehensive Heport by Wheeler, Woodward-Clyde and Associates.

Data on water applied to the land were obtained from tabulations supplied by the U.S. Bureau of Reclamation Office in Pueblo.

These data included releases from reservoirs. The amounts of precipitation received by the irrigated area were obtained from Weather Bureau records: while the consumptive use was evaluated by using the procedure of l\1unson.4- The method of estimating the monthly amounts of return flow will be explained in detail in a later paragraph.

The effect of pumping is not explicitly accounted for but is evaluated" implicitly in the area assumed to be irrigated and the estimated consumptive use. The supposition here is that the neads of the crops are supplied somehow by water conveyed in canals, by pumping or by some combination of these. The consumptive use on areas served in whole or in part by pumps does not contribute to return flow and the effect of pumping on such areas is reflected in reduced return flow figures because the consumptive use on these areas is accounted for.

Data on the consumption of water by phreatophytes was obtained from the April

1963

Study of Phreatophyte Growth in the Lower Arkansas River Valley of Colorado by Morton W. Bittinger and Glen E. Stringham. I

To evaluate the return flows the permeable sediments of the river valley were idealized as occupying a straight trench of

uniform width and depth in the underlying impermeable shales.~ The river was idealized as following a straight course down the middle of the permeable strip. The Maasland development3

applied to the flow of ground water to parallel drains at the spacing L but since there is no flow across a vertical plane midway between the drains the flow pattern can be cut in two there and the two halves shifted to bring the drains into coincidence. The flow pattern so obtained can be used to represent dr~inage, from permeable sedi-ments resting in a trench of width L incised into impermeable formations. The river behaves as the drain. To adapt the Maasland idealization to computation of total flows, accumulating during a month, the flow rates found from his solution are integrated with respect to time to obtain total flows and these are then differ-enced as explained under the heading "Computation of Return Flows" to get the return flows which appear in the river in months sub-sequent to the month of application. If there is a question as to whether the actual river conditions can be effectively assimilated to a straight uniform strip with the river traversing the middle of the strip, it may be explained that supplementary investigations have disclosed that the results obtained by use of this idealiza-tion are strongly determined in that they are insensitive to the width of the strip and to the position of the river in the strip so long as the amounts of water reaching the water table remain unchanged and there has been time to establish a regimen.

Supplementary computations also indicate that about 4 years would suffice for the establishment of a new regimen following a change of irrigation practices. For the purpose of these computations the width of the idealized strip was taken to be L

=

16000 feet. The aquifer constant used was

oc..

=

0.64 ft 2/ sec.?' The months

were also assumed to be of a uniform one-twelfth year or 2628000 seconds in length.

The sum of the factors shown later should total to 1.0000 and they would if a sufficiently long time period were used. Where the factors are totaled for a two year period the result is

0.82050. The effect of all increments which appeared before the two year interval can be approximated by multiplying the 0.17950 remainder by the average monthly contribution to the water table. In the present case this is 16030 acre feet. The product

(0.17950)(16030)

=

2877 is the "residue" shown later. Acknowledgements

Mr. Harlan Erker of the state Engineer's Office contributed generously of his time in a search of records for useful data. Mr. John Patterson contributed useful information as to where certain data could be found. Messrs E.A. Moulder, C.T. Jenkins and others of the U.S. Geological Survey contributed from their records and their knowledge of the Arkansas Valley. Mr. Don Miles of the Colorado State University Extension Service contributed data on winter irrigation tests. Tabulations of water quantities applied to the land were received from Mr. J.L. Ogilvie, Project Manager of the Fryingpan-Arkansas .Pueblo Office of the U.S. Bureau of Heclamation. Annual Reports of the Fort Lyon Canal Company for the period 1951 - 1962 inclusive w~re contributed by this Company. This study has profited much from discussions with Mr. A. Ralph Owens who drew upon his extensive knowledge of conditions in the valley to clear up some troublesome questions.

Details of the computations are shown on some following pages. A somewhat erratic behavior is to be expected in the results

obtained from computations of the type described. This is due to the final result being often a small residue obtained from addition and subtraction of relatively large numbers. In this process the errors which may be present in the primary factors are carried over bodily into the result. Sometimes these discrepancies may nearly annul each other but at other times they may add and it is impossible to tell which way chance will operate. It can be hoped that further studies will point the way to a more effective use of the available data and contribute information not available to the study. It seems reasonable to suppose, for example, that the

winter irrigations may incur evaporation losses not contemplated in the consumptive use pattern obtained by application of Munsons factors. If so, it may help to reduce the discrepancies between estimated and observed flows in the winter months. It may be also that some areas served by wells may not be included in the areas used as a basis for the study. It seems certain, however, that

ground water storage and return must be evaluated in future operations studies becquse the sum of the canal diversions and the river flow at Las Animas exceeds the surface inflows to the reach. This can not be easily explained on the basis of surface flows only.

The final 18,,685. acre foot discrepancy between the estimated and observed flows at Las Animas is only about 3 percent of the sum of the river inflows~for the year.

~~~-Hobert

E.

Glover

December 26, 1969

4-T

factor Water reaching the

water table A.F.

T 1 2 2. 1 5 1 9 9. 3 6 _{.0 1 1. 9 5} 17~31 _{1 263} 1 ~ 6.39 _{1 3.5 8} 1 1 5.9 8 _{1 4.36} 1 3 4.6 7 _{1 5.4 3} 17~29 _1&34 2 ~ 0.72 _{1 7.5 4} 3 2 5.78 _{1 8.5 9} 1 6 L 2 8 _{1 9.94} 1 07.9 1 _{2 1.14} :21.35- _~2.68 1 2 215 _2~08 1~~36 _2~84 1 7 3.31 _{2 7.4 9} 13&39 _2~56 11~98 3L60 1:3~67. _S~20 1 7 7.2 9 _{3 7.0 1} 2~Q72 _4Q83 32~98 _4~57 1 61.28 _53.00 1 0 7. 9 1 _{• 0 6 5. 4 3} 2 L:3 5 - _{~ 1 0 O. 3 5} 1 22.1 5 T _{,1 2 1.:S 6} 1 ~ 9. 3 6 _{,8 :2 O. 5 u S} 1 7 3.3 1 1.0 0

u.

u

u-1 :.s 6. :3 9 _{,1 7 9. 5 0 2:} 1 1 5.9 8 -Sum of Droduc-~s' 1 ::5 4.6 7 _{11597. plus th; ,} 1

?

7. 2 9 residue _{2877. =} 2 ;; O. 7 2 14474. A. F 3 25.9 8 _•

1 6 1. 2 8 _{This is the estimateo.}

1 0 7. 9 1 _{return flow for} October. Oct Nov Dec Jan Feb Mar I Apr May June July Aug Sept Oct Nov Dec Jan Feb Mar Apr May June July Aug Sel)t Qct Nov Dec

Jan

Feb :Mar Apr May June July Aug

f

t:

_n::

₀₀

_'Z

_{Z(LXJt )}

df:

_-nrr

1.

5 __

Q.{

L~~)"

e

₁₂

_{_ _}

_'

(~)

-\

1T

4

\IX.f,L

_n4

_{\1. \}

_oct

V1=\:>5···1\ J , _.

~ote _{that the left hand member of this expression}

represents, for a _{unit length of stream, the ratio of} the total return to the total application out to the

time t.

If values are computed for !qdt _{at one month}

intervals

ana

_{each of these values is subtracted}

from the one succeeding it a _{sequence of values will}

be obtained which will represent the total return from an application lasting only during the first

month. _{If each of these values is, in turn,}

sub-tr2cted from the one succeeding it a set of factors will be obtained Which will represent the ratio of the return flow during a succeeding month to the water reaching the _{water table in the first month. A set}

of such factors is shown at the right. These were computed by the use of unpublished tables prepared by digital computer operation at Colorado State University.

computation of return flows.

The total return flow

fq~t

per

Dni~

_{length of}

stream, due to an infiltration rate 1 applied to a valley width L _{is given by the expression}

References

(l)Bittinger, Morton W. and Stringham, Glen E. - A Study of Phreatophyte Growth in the Lower Arkansas Valley of Colorado.-April 1963. Report CER63MWB-GES6 - Civil Engineering Section,

Colorado Agricultural Experiment Station Colorado State University, Fort Collins, Colorado.

(2)Glover, R.E. - The Pumped Well - Technical Bulletin 100. Colorado State University Experiment Station, Fort Collins - Sept. 1968.

(3)Maasland, Marinus - Water Table Fluctuations Induced by Irrigation-Trans ASCE Vol 128 1963 Part III p 142-159.

(4)Munson, Wendell C. - Method for Estimating Consumptive Use of Water for Agriculture. Trans ASCE Vol 127 1962 Part III p

200-220.

(5)U.S.G.S. Water Supply Paper 1731 - Compilation of Records of

Surface Watemof the United StatesT October 1950 to September 1960-Part 7 Lower Mississippi River Basin.

(6)U.S.G.S. W.S.P. 1799 Geology and Occurrence of Ground Water in Otero County and the Southern Part of Crowley County, Colorado.

( 7)Weather Bureau - Mean Monthly and Annual Evaporation from :F'ree Water Surface .•••• Technical Paper 13. Washington, D.C. 1950.

(S)Weather Bureau - Climatic Summary of the United states

-Climatography of the United States 86-5 Colorado. Supplement for 1951 through 1960. Washington, D.C. 1964.

(9)U.S.G.S. - Geologic Map of Colorado.

(]~Water Legislation Investigations for the Arkansas River Basin

in Colorado. Voltime II Comprehensive Report. W.W. Wheeler and Associates Woodward Clyde and Associates Consulting Engineers

Denver, Colorado September 1968. (This reference added May 1, 1978).

~G

THE UNIVERSITY OF ARIZONA

T U C SON, A R I Z 0 N A 85721

COLLEGE OF EARTH SCIENCES

DEPARTMENT OF HYDROLOGY AND WATER RESOURCES TEL. (602) 884-3131

September 27, 1972

Professor Robert E. Glover Dept. of Civil Engineering Colorado State University Ft. Collins, Colorado 80521 Dear Bob:

After our phone conversation I checked our files and found the

carbon of a letter to you dated on August 25th. A copy of this

carbon is enclosed. At that time we returned your original

paper and abstract. If you have not received this correspondence

and your papers, I am at a loss to explain what happen~d. Please

let us know the situation after re-checking your files.

Of possible interest to you might be the attached paper on "Error

Annlysis ••• " put together late in 1970. As yet we have not seen

fit to extend it and submit it to a Journal for review. Some

decision issues are broached on pages 21-22. In the context of

the paper, your results lead to a point estimate (this is a

sta-tistical term). The key question is how good (in some sense) is

t9at estimate. This is also discussed in our manuscript. I

believe that there is need for interaction of different points of view; otherwise, a fresh synthesis will not arise.

Your paper with J.W. Patterson could be identified as Paper 3.14

for the session on "Uncertainties in Deterministic Models." But it

is too late to list it as such on the program. Under these terms

you may wish to resubmit your manuscript before the October 15th

deadline. A change in title of the paper may be in order to

des-cribe more accurately what you have done. No French abstract is

required.

I hope that the above information is an adequate follow up to our

phone conversation. Please let us know.

Sincerely,

Chester C. Kisiel Professor of Hydrology and Water Resources CCK:dag

REGISTRATION FORM December 11-14, 1972 Name Position or Title Organization Office Address . \

City State Zip

Registration fee is $30.00. Make check payable to the INTERNATIONAL SYMPOSIUM ON UNCERTAINTIES IN HYDROLOGIC AND WATER RESOURCE SYSTEMS and mail to:

Chester C. Kisiel, Chairman The Organizing Committee Department of Hydrology and Water Resources

200 E. Old Psychology Bldg. University of Arizona

Tucson, Arizona 85721

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