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Water resources of the vernon irrigation district Johnston, Ronald Harvey 1971

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WATER RESOURCES OF THE VERNON IRRIGATION DISTRICT  by  RONALD HARVEY JOHNSTON B.Sc.(Eng.), University of Guelph, 1968  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE i n the Department of C i v i l Engineering We accept t h i s thesis as conforming to the required standard  The University of B r i t i s h Columbia November* 1971  In p r e s e n t i n g t h i s  thesis  an advanced degree at the L i b r a r y I  in p a r t i a l  the U n i v e r s i t y  s h a l l make i t  freely  f u l f i l m e n t o f the of B r i t i s h  available  for  requirements  Columbia, I agree  that  r e f e r e n c e and study.  f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e copying o f t h i s  for  for  thesis  s c h o l a r l y purposes may be granted by the Head o f my Department o r  by  his  of  this  representatives.  It  thesis for financial  i s understood that copying o r p u b l i c a t i o n gain shall  written permission.  Department o f  C i v i l Engineering  The U n i v e r s i t y o f B r i t i s h Columbia Vancouver 8, Canada  Date  November 26, 1971  not be allowed without my  i.  ABSTRACT  The Okanagan V a l l e y i s an important a g r i c u l t u r a l area i n south-central B r i t i s h Columbia.  Due  to the low annual  precipitation  and a high rate of evapotranspiration, i r r i g a t i o n i s necessary f o r the production of most crops.  Since water shortage problems i n the v a l l e y are l i k e l y to a r i s e i n the future, since i r r i g a t i o n accounts f o r over 90% of the consumptive use of water i n the v a l l e y , and since data on the a c t u a l i r r i g a t i o n operation i s sparse, a d e t a i l e d study was made of one district.  Vernon I r r i g a t i o n D i s t r i c t , the l a r g e s t d i s t r i c t i n the Okanagan Basin, was selected f o r d e t a i l e d study. system has r e c e n t l y been modernized.  Its distribution  The history of the development of  the d i s t r i c t i s outlined and the old system and the way operated are described.  The reasons f o r s e l e c t i o n of the new  the c r i t e r i a used i n i t s design, and the way now  i n which i t  operates are described.  i n which the new  system, system  P a r t i c u l a r a t t e n t i o n i s paid to  s c h e d u l i n g — t h e timing of the a p p l i c a t i o n of water to the c r o p s — s i n c e t h i s o f f e r s one of the best opportunities f o r the conservation of water i n the f u t u r e .  Minor c o n f l i c t s with other users of the water resource ,  are i d e n t i f i e d and suggestions given f o r minimizing such c o n f l i c t s .  TABLE OF CONTENTS  Page ABSTRACT  i  LIST OF TABLES  i i  LIST OF FIGURES  i i i  ACKNOWLEDGMENTS  iv  Chapter I. II. III.  INTRODUCTION  . . . . .  1  VERNON IRRIGATION DISTRICT  4  GENERAL DESCRIPTION  .  CLIMATE  6  HISTORY  8  OPERATION OF THE OLD IRRIGATION SYSTEM III.  k  14  NEW IRRIGATION SYSTEM  17  DESIGN  17  Comparison of A l t e r n a t i v e s  . . . . . . . . . .  Design C r i t e r i a f o r the Old Pipeline System Duty  . .  . . . . . . . . . . . . . . . . . . . . . . .  Maximum Demand Rate Pressure  . . . . . . . . . . . .  Reservoir System  „  19 19 20  OPERATION OF NEW IRRIGATION SYSTEM D i s t r i b u t i o n System  17  21 21 21 -26  Chapter IV.  V.  VI.  Page SCHEDULING THE APPLICATION OF WATER  33  EQUIPMENT USED IN SCHEDULING ,  33  GENERAL PROCEDURE  35  CREDIT FOR RAIN  37  CHOOSING A SITE FOR THE EVAPORIMETER  39  SCHEDULING FOR IRRIGATION DISTRICTS  39  ADVANTAGES OF SCHEDULING  40  PROBLEMS WITH SCHEDULING  41  USE OF SCHEDULING  43  ADDITIONAL USES OF DUTEAU CREEK  45  FISHERIES  45  FLOOD PROTECTION AT LUMBY  49  PLANS FOR THE FUTURE  50  CONSTRUCTION OF ADDITIONAL STORAGE  50  MANAGEMENT  51  ..  Economic Incentive  51  Extra Equipment  52  . . . . . . . . .  Better Operation of Reservoirs  . . . . . . . .  53  Scheduling  53  Drip I r r i g a t i o n  5^  SUMMARY VII.  . .  CONCLUSIONS  54 56  BIBLIOGRAPHY  57  GLOSSARY  59  ii.  L I S T OF TABLES ,  Table I. II. III.  Page CLIMATIC DATA  7  LAND USE  8  CATCHMENT AREA, STORAGE, AND GOVERNING WATER LEVELS OF VERNON IRRIGATION DISTRICT RESERVOIRS  28  iii.  LIST OF FIGURES  Figure  Page  1.  OKANAGAN BASIN IN BRITISH COLUMBIA  2.  HISTORIC DITCHES  10  3.  NEW IRRIGATION PIPELINE  22  4.  STORAGE RESERVOIRS OF VERNON IRRIGATION DISTRICT . . .  2?  5.  HYDROGRAPHS OF LAKE INFLOW AND RELEASE IN HIGH FLOW YEAR  30  6.  5  HYDROGRAPHS OF LAKE INFLOW AND RELEASE IN LOW FLOW YEAR  31  7.  BALANCE SHEET  34  8.  BELLANI PLATE EVAPORIMETER  36  9.  OGOPOGO EVAPORIMETER  36  10. 11.  12.  13.  DAILY EVAPOTRANSPIRATION AT SUMMERLAND RESEARCH STATION, 1971 FLOODING AND SPAWNING LOCATION IN DUTEAU CREEK WATERSHED  46  DISCHARGE IN DUTEAU CREEK BELOW THE VERNON IRRIGATION DISTRICT DIVERSION, LOW FLOW YEAR, I963  47  DISCHARGE IN DUTEAU CREEK BELOW THE VERNON IRRIGATION DISTRICT DIVERSION, HIGH FLOW YEAR  48  42  iv.  ACKNOWLEDGMENTS  During the course of t h i s study, many people have given f r e e l y of t h e i r time i n order to a s s i s t me.  To the following I  express my sincere a p p r e c i a t i o n i  B. S, Harvey, I r r i g a t i o n Manager-Engineer, Vernon I r r i g a t i o n D i s t r i c t , f o r h i s time spent i n showing the i r r i g a t i o n system and f o r access to the Vernon I r r i g a t i o n D i s t r i c t records, P, Kowalchuk, Chief Water B a i l i f f , Vernon I r r i g a t i o n D i s t r i c t , f o r his time spent showing the storage r e s e r v o i r s of the D i s t r i c t , D. S, Stevenson, I r r i g a t i o n S p e c i a l i s t , Summerland Research Station, f o r demonstrating scheduling and providing evaporation data, C, H, Brownlee, I r r i g a t i o n S p e c i a l i s t , B r i t i s h Columbia Department of A g r i c u l t u r e , Kelowna, f o r time spent i n discussing various aspects of i r r i g a t i o n i n the area, J , Eby, Water Investigations Branch, B r i t i s h Columbia Department of Lands, Forests, and Water Resources, V i c t o r i a , f o r time spent discussing the design of the new i r r i g a t i o n system, T, J , Wilcox, Canada Department of F i s h e r i e s , Vancouver, f o r time spent discussing the f i s h e r i e s resource of the Vernon area, S. 0, Russell, Department of C i v i l Engineering, University of B r i t i s h Columbia, Vancouver, f o r ably supervising the development of this thesis.  1  CHAPTER I  INTRODUCTION  The Okanagan Valley i s a broad, i r r e g u l a r r i f t - v a l l e y i n the i n t e r i o r o f B r i t i s h Columbia extending approximately 120 miles north from the Canada-United States border.  The average annual p r e c i p i t a t i o n  v a r i e s from about 15 inches i n the northern part of the v a l l e y near Vernon, which i s barely s u f f i c i e n t f o r the production of some forage and pasture crops, to about 8 inches a t Osoyoos i n the s o u t h . M a n y crops f l o u r i s h i f provided with a d d i t i o n a l moisture through i r r i g a t i o n .  Since before 1900, a g r i c u l t u r e has been the most important economic a c t i v i t y i n the v a l l e y although tourism has expanded g r e a t l y i n the l a s t decade.  The i r r i g a t i o n systems which supply water f o r the  farms were mostly begun e a r l y i n the century and consequently by the 1950's, had not only become rather obsolete i n terms of todays i r r i g a t i o n technology but a l s o most of the systems needed r e h a b i l i t a t i o n to conserve water and increase t h e i r r e l i a b i l i t y .  In the l a s t decade  many of the d i s t r i b u t i o n systems of the i r r i g a t i o n d i s t r i c t s i n the Okanagan have been r e h a b i l i t a t e d under the A.R.D.A. agreement •whichallows f o r f e d e r a l and p r o v i n c i a l assistance.  With growing problems of water  shortage and water p o l l u t i o n as the v a l l e y population and i n d u s t r i a l i z a t i o n increases, the f e d e r a l and p r o v i n c i a l governments have undertaken a j o i n t study of water quantity and q u a l i t y management i n the Okanagan basin.  2 Since i r r i g a t i o n accounts f o r more than 90% of the consumptive use of water, f a m i l i a r i t y with i r r i g a t i o n i s necessary i n order to carry out studies of water resources i n the Okanagan Valley, Unfortunately, discharge and consumptive use data are a t best scattered and incomplete and, i n any case, records of the amount of i r r i g a t i o n water used, say, twenty years ago are of l i m i t e d use today when i r r i g a t i o n p r a c t i c e s , e f f i c i e n c y of a p p l i c a t i o n , and crops are s u b s t a n t i a l l y d i f f e r e n t from what they were.  To obtain an understanding of i r r i g a t i o n practice i n the Okanagan, i t was decided to study a p a r t i c u l a r i r r i g a t i o n d i s t r i c t i n d e t a i l to f i n d out how i t a c t u a l l y operated and to t r y to i d e n t i f y problems and c o n f l i c t s with other resource users and opportunities f o r better management.  Vernon I r r i g a t i o n D i s t r i c t , the l a r g e s t d i s t r i c t i n  the Okanagan Valley was selected f o r the study.  Although i t has a  lower water consumption per acre than other d i s t r i c t s i n the Okanagan, Vernon I r r i g a t i o n D i s t r i c t i s t y p i c a l i n that i t has several r e s e r v o i r s with a r e l a t i v e l y complex operating pattern, and records of water a v a i l a b i l i t y and consumptive use are not a v a i l a b l e .  Also replacement  of the o l d d i s t r i b u t i o n system by a new one has j u s t been  completed,  thus o f f e r i n g an opportunity to study a modern i n s t a l l a t i o n .  In t h i s thesis, the h i s t o r y of the development of the d i s t r i c t i s f i r s t outlined to give some background perspective, and the o l d system and i t s operation i s described.  The reasons f o r s e l e c t i n g the  new system are outlined and the c r i t e r i a used i n i t s design are given. Operation of the pipeline and r e s e r v o i r systems, and scheduling, the  3 procedure f o r deciding when to apply water to a crop are described. Some minor c o n f l i c t s f o r water use were evident and these are described together with suggestions f o r managing the water supply to minimize such c o n f l i c t s i n the f u t u r e .  4  CHAPTER I I  VERNON IRRIGATION DISTRICT GENERAL DESCRIPTION The Okanagan Valley i s a dry v a l l e y i n the south-central i n t e r i o r of B r i t i s h Columbia (Figure l ) . winters are c o o l and moderately dry.  Summers are warm and dry and  H i s t o r i c a l l y , the main industry  has been a g r i c u l t u r e although i n recent years tourism has become i n c r e a s i n g l y important.  Since the climate i s so dry, i r r i g a t i o n i s  required f o r almost any form of a g r i c u l t u r e i n the v a l l e y .  The Vernon I r r i g a t i o n D i s t r i c t (referred to as V.I.D. i n t h i s t h e s i s ) l i e s a t the north end of the Okanagan V a l l e y .  I t encompasses a  t o t a l of 27,400 acres of which approximately 9200 acres were registered f o r tax purposes as being i r r i g a t e d i n 1971.  The i r r i g a t e d lands l i e  generally along the east-west Coldstream Valley and the north-south v a l l e y which leads from the Columbia-Fraser watershed boundary i n the north to Okanagan and Kalamalka Lakes i n the south. i r r i g a t e d lands v a r i e s from 1200  to 2100  feet.  The a l t i t u d e of  High, tree covered  t e r r a i n extends beyond the steep-sided v a l l e y s both north and south of the D i s t r i c t to an elevation of about 6000 f e e t .  Since p r e c i p i t a t i o n  increases with elevation while evaporation decreases with elevation, most of the run-off originates from the higher l e v e l s .  Most of the  run-off comes from snowmelt and as a r e s u l t peak flows occur i n May e a r l y June,  and  Excess water i s stored i n Haddo, Aberdeen and King Edward  5  KEY  Fig. I O K A N A G A N  BASIN IN BRITISH  MAP  COLUMBIA.  Lakes which l i e to the south of the D i s t r i c t a t an elevation of 4000 to  4500 f e e t .  The stored water i s released to meet i r r i g a t i o n needs  l a t e r i n the i r r i g a t i o n season when the demand exceeds the unregulated flow from the remainder of the watershed.  Although I r r i g a t i o n i s  required f o r most crops, p r e c i p i t a t i o n (which i s higher i n the D i s t r i c t than elsewhere i n the Okanagan Valley and much higher than i n the southern portion of the v a l l e y ) i s s u f f i c i e n t to permit some crops such as hay, to grow without i r r i g a t i o n .  CLIMATE  With an average of 150 f r o s t free days a year, Vernon a t l a t t i t u d e 50° 15' north, l i e s a t the approximate northern l i m i t f o r the commercial growing of tree f r u i t s In the i n t e r i o r of B r i t i s h Columbia. The climate i s mild continental with warm summers, cool winters, and low annual p r e c i p i t a t i o n .  Cold s p e l l s of below zero temperatures  may  be  expected every winter with below f r e e z i n g temperatures occurring between mid-September and mid-May, though prolonged periods of extreme c o l d are r a r e .  The f o l l o w i n g table gives an i n d i c a t i o n of the c l i m a t i c  conditions of the area.  7 TABLE I  CLIMATIC DATA  Vernon  Vernon (Coldstream)  Elevation i n f e e t  1383  1582  Average January Temperature  23°F  21°F  Average July Temperature  68°F  66°F  Average January P r e c i p i t a t i o n  1.7"  1.5"  Average July P r e c i p i t a t i o n  1.0"  1.2"  15.5"  15.1"  Average Annual P r e c i p i t a t i o n Average Frost Free Days  147  151  The proportion of the land devoted to various a g r i c u l t u r a l a c t i v i t i e s varies from year to year but the following  table taken from  "Farming i n the Vernon I r r i g a t i o n D i s t r i c t " (l4), gives an i n d i c a t i o n of the r e l a t i v e importance of the various c r o p s  0  8 TABLE I I  LAND USE  UNDER IRRIGATION TOTAL ACRES  ACRES  2553  2519  99  37  709  707  100  10  Grain  II65  312  27  5  Hay  3265  I887  58  27  Pasture  3337  1097  33  16  Other  6551  366  6  5  CROP  FruitVegetables  Total  17,580  PERCENT OF CROP  PERCENT OF TOTAL IRRIGATED AREA  6888  Of a t o t a l of 6888 acres i r r i g a t e d , 3268 acres comprised grain, hay or pasture with a low I r r i g a t i o n water requirement compared to tree fruits.  This, along with higher p r e c i p i t a t i o n and lower evaporation,  accounts f o r the f a c t that Vernon I r r i g a t i o n D i s t r i c t has a lower t o t a l annual water demand than d i s t r i c t s i n the south Okanagan Valley where tree f r u i t s form a higher proportion of the t o t a l crop,  HISTORY In I892, the E a r l of Aberdeen purchased the Coldstream Ranch from the Honorable Forbes George Vernon,  His i n t e n t i o n was to develop  the land by bringing i r r i g a t i o n water to i t and then s e l l the improved  9 land to s e t t l e r s .  I t can be said that this was the beginning of  commercial f r u i t growing i n the Okanagan.  I r r i g a t i o n was actually-  i n s t i t u t e d by the Honorable Couttes-Marjorie Banks, manager of the Coldstream Ranch, who employed Mr. F. B. Kirby, B.C. Land Surveyor to survey a d i t c h f o r i r r i g a t i o n of part of the Ranch,  This d i t c h was  constructed and expanded i n l a t e r years to serve lands f u r t h e r down the valley. I965.  I t became known as the North Ditch and was s t i l l i n use i n The Coldstream Estate Company was formed to develop and to s e l l  the i r r i g a t e d land.  Another Ranch manager, Mr. Ricardo, developed the  Orchard Ditch, King Edward, Abbotsford and Walker systems from l o c a l sources of water—mostly diversions of Coldstream Creek (Figure In 1905,  Mr. Ashcroft was engaged to survey the Duteau Creek  2 ).  watershed  to determine the f e a s i b i l i t y of using i t f o r i r r i g a t i o n supply purposes.  On h i s recommendation, the canals now known as the Grey and  South Canals were subsequently constructed along the north and south sides of the Coldstream Valley,  For the control and ownership of t h i s new system, which was to serve the lands east of the B.X, Creek, The White Valley Power and I r r i g a t i o n C:ginall;  was formed, the shares i n t h i s company being i  the Coldstream Estate Company.  By an arrangement  with the Land and Agriculture Company, the Grey Canal was extended west and north, and f i n a l l y across the Swan Lake Valley to Goose Lake i n  1910,  and north and south from there to eventually s p i l l excess water i n t o Okanagan Lake i n  By 1915,  1914.  approximately $423,000 had been spent on the system,  11  the operating l o s s that year was $ 1 2 , 0 0 0 , need of r e p a i r .  and the system was badly i n  On the advice of Mr. E. A. Cleaveland, Comptroller of  Water Rights, the land owners petitioned the p r o v i n c i a l government to form an improvement d i s t r i c t under the Water Act.  As an improvement  d i s t r i c t , the area would be e l i g i b l e f o r p r o v i n c i a l assistance f o r improving the water d i s t r i b u t i o n system.  The p e t i t i o n was granted and  i n 1 9 2 0 the area was formed i n t o a d i s t r i c t and named the Vernon Irrigation  District.  Under the Water Act, the Lieutenant Governor i n Council has the power to incorporate an area i n t o an improvement d i s t r i c t by L e t t e r s Patent.  An improvement d i s t r i c t i s a public corporate body and may have  a l l the powers necessary to carry out i t s o b j e c t i v e s . Among i t s powers are the power to sue and be sued, to borrow money, to issue bonds, to levy and c o l l e c t taxes and t o l l s , and to construct and maintain works f o r the d i s t r i b u t i o n of water.  The powers of the d i s t r i c t are exercised  by Trustees who are elected by the landowners i n the d i s t r i c t .  Since incorporation i n 1 9 2 0 , the Vernon I r r i g a t i o n D i s t r i c t passed through several periods of hard times, engaged as General Manager i n 1 9 3 7 »  a n d  more permanent works was i n s t i t u t e d .  has  Mr. G. C. Tassie was  - under h i s guidance a program of However, lack of funds  prevented  any major program of r e h a b i l i t a t i o n , and only the more c r i t i c a l parts of the system received a t t e n t i o n . Between 19^5 and 1 9 6 3 , r e p a i r s included l i n i n g of parts of the canal system with concrete slabs to prevent seepage, replacement cement pipe.  of s t e e l flumes, and l a y i n g of some asbestos-  12 In general, up u n t i l construction of the new i n 19^5»  system commenced  lack of money prevented any but the most urgent r e p a i r s and  replacements from being made.  In l 6 l , the f e d e r a l government passed Q  the A g r i c u l t u r a l and Rural Development Act (A.R.D.A.). that the minister may,  with the approval  This a c t states  of the Governor i n Council,  enter i n t o an agreement with any province providing f o r the j o i n t undertaking of projects f o r the development of income and employment opportunities i n r u r a l areas.  Included  are  projects f o r the development  of water supplies f o r a g r i c u l t u r a l or other r u r a l purposes and  projects  f o r the more e f f i c i e n t use and economic development of r u r a l lands, Under t h i s agreement, project costs are divided equally among the p r o v i n c i a l and f e d e r a l governments and the landowners i n the b e n e f i t i n g area.  When, i n 19&2,  the Vernon I r r i g a t i o n D i s t r i c t manager resigned,  the d i s t r i c t trustees decided i r r i g a t i o n manager.  to t r y to operate the d i s t r i c t without an  An engineering  consultant who  was  c a l l e d i n to  a s s i s t i n the operation of the system, suggested that a renewal program be i n s t i t u t e d . The trustees went to the Department of Lands, Forests, and Water Resources to obtain assistance i n planning.  The Water  Investigations Branch c a r r i e d out a study of the V.I.D. i n 1964  and  I965, under the A.R.D.A. agreement with the assumption of A.R.D.A. financing.  In I965 a report was  prepared which compared the f e a s i b i l i t y  of r e h a b i l i t a t i n g the old system with the construction of a completely new  pipeline system,,  The study considered  only the water d i s t r i b u t i o n  system although the a p p l i c a t i o n method was a consideration i n design. The study was quite comprehensive since, to quote the report,  "any  decision to adopt an a l t e r n a t i v e which involves abandoning works that have successfully provided i r r i g a t i o n water to the D i s t r i c t f o r over f i f t y years, should not be made before an a l t e r n a t i v e of improving the e x i s t i n g system i s c a r e f u l l y s c r u t i n i z e d " (5).  Although the study  d e a l t mainly with the r e h a b i l i t a t i o n of the d i t c h system and the construction  of a pipeline system, other a l t e r n a t i v e s considered i n the  study were j 1,  pressurization of the e x i s t i n g system  2.  c a n a l i z a t i o n of Coldsteam Creek  3.  pumping from Okanagan, Kalamalka, and Swan Lakes  4,  pumping from Okanagan Lake to supply the B e l l e V i s t a area  These a l t e r n a t i v e s posed problems of screening, blockage of s p r i n k l e r s , high cost of pumping schemes compared to gravity, and generally higher costs than r e h a b i l i t a t i n g the d i t c h system or construction consideration  of a buried pipeline system.  Therefore, no extensive  was given to the a l t e r n a t i v e s l i s t e d above, and instead,  the study concentrated on the a l t e r n a t i v e s of r e h a b i l i t a t i n g the d i t c h system and providing a new p i p l i n e system. i n the study are outlined i n Chapter I I I ,  The main points considered The pipeline system was  chosen and between 1965 and 1970» the Vernon I r r i g a t i o n D i s t r i c t gradually changed to the pipeline system. operated e n t i r e l y without d e l i v e r y  ditches.  In 1971 the D i s t r i c t  14  OPERATION OF THE OLD IRRIGATION SYSTEM  The old d i s t r i b u t i o n system of the Vernon I r r i g a t i o n D i s t r i c t , parts of which were i n use u n t i l 1970, consisted of some 57 miles of open canals and about 37 miles of d i s t r i b u t i o n p i p e l i n e .  Most of i t  was constructed between 1900 and 1920 or before the D i s t r i c t was incorporated.  Water was regulated by storage and release from Aberdeen and Haddo Lakes.  A f t e r release from Haddo Lake, the water flowed down  Duteau Greek to the Vernon I r r i g a t i o n D i s t r i c t d i v e r s i o n a t which point the water entered the Grey Canal a t the approximate elevation of 2150 feet.  From the canal, the water was conveyed by syphon and flume to the  i r r i g a t o r s land.  The farmers had to order water f o r i r r i g a t i o n a t l e a s t twentyfour hours i n advance of the desired d e l i v e r y time.  The water was  ordered from the Water B a i l i f f who i n turn ordered the water from the Chief Water B a i l i f f .  The Chief Water B a i l i f f added up a l l the water  required f o r a l l the areas, added an amount f o r seepage losses, and ordered the dam operator a t Haddo Lake to open or close the c o n t r o l as required to supply the estimated amount.  The amount of excess water  ordered to s a t i s f y seepage losses was i n the order of 30 per cent.  Regulation  of water was generally by means of gates and valves  located along the canal.  The morning that the i r r i g a t o r was to  receive water, the Water B a i l i f f a r r i v e d to open the c o n t r o l a t the  15 farmer's o u t l e t .  This c o n t r o l was the property of the D i s t r i c t and only  employees of the D i s t r i c t were permitted to adjust i t .  I r r i g a t o r s paid  only f o r water a c t u a l l y used hy them, and i t was measured by means of weirs or gates or by c a l c u l a t i o n from s p r i n k l e r nozzle s i z e s and supply pressure.  There were problems with t h i s type of measurement as sometimes the measuring flumes were t i l t e d by f r o s t a c t i o n or blocked by debris from the canal.  When the f r o s t a c t i o n occurred, i t was necessary to  r e c a l i b r a t e the flume, whereas i n the case of debris blockage, the D i s t r i c t was usually obliged to extend the period of flow to make up f o r the reduced discharge r a t e .  Twenty-four hours before the farmer  f i n i s h e d i r r i g a t i n g , he would again c a l l on the Water B a i l i f f to shut off the water.  The farm i r r i g a t i o n systems i n the Vernon I r r i g a t i o n D i s t r i c t consisted mainly of furrow i r r i g a t i o n i n which the f i e l d had furrows constructed with gentle slopes to prevent erosion.  The i r r i g a t o r allowed  water to flow down a furrow u n t i l the ground had enough moisture, then sealed o f f that furrow and transferred the flow to the next furrow. This operation was repeated u n t i l the f i e l d or farm was i r r i g a t e d .  The  farmer had no s c i e n t i f i c method of knowing when the land was s u f f i c i e n t l y moist, but r e l i e d on h i s experience and knowledge of the physical c h a r a c t e r i s t i c s of h i s own s o i l — t h e f e e l , look and smell of it.  I f i n s u f f i c i e n t water were applied to the crop,  consequences  ranged from sub-optimal growth to permanent w i l t i n g and l o s s of the crop.  Therefore, i t was natural that the i r r i g a t o r would t r y to apply  16 more water than necessary i n order to have a safety margin.  This safety  margin was also good from the point of view of s a l t build-up as s a l t concentrations  may  b u i l d up to l e v e l s toxic to the crop, i f i n s u f f i c i e n t  drainage water passes through the root zone.  Therefore,  some a p p l i c a t i o n  of i r r i g a t i o n water over and above that required f o r consumptive use i s desirable to leach soluble s a l t s from the root zone.  For the Okanagan,  leaching requirements are f a i r l y modest and i t i s generally that over winter p r e c i p i t a t i o n i s almost s u f f i c i e n t to leach undesirable  s a l t s from the root zone.  considered  17  CHAPTER I I I  NEW  IRRIGATION SYSTEM  DESIGN  In order to take advantage of the opportunities offered under the A g r i c u l t u r a l and Rural Development Act, the trustees of the Vernon I r r i g a t i o n D i s t r i c t requested the Department of Lands, Forests, and Water Resources to carry out a study to determine the best method of r e h a b i l i t a t i n g the i r r i g a t i o n system. which was  This was done and i n the report,  published i n 19&5» two main a l t e r n a t i v e s were examined.  The  f i r s t involved replacement of a l l components i n the e x i s t i n g system with a remaining l i f e of l e s s than twenty-five canals.  The second scheme involved a new  of p i p e l i n e buried below the f r o s t l i n e .  years and l i n i n g the  system c o n s i s t i n g e n t i r e l y The supply pressure would be  supplied generally by g r a v i t y , but some pumping would a l s o be  involved.  Comparison of A l t e r n a t i v e s The estimated annual cost per acre over twenty-five years twenty-three d o l l a r s f o r reconstructing the d i t c h system and eight d o l l a r s f o r the new the p i p e l i n e system was  p i p e l i n e system.  chosen.  was  twenty-  Despite the cost d i f f e r e n c e ,  The main reasons f o r the choice of the  p i p e l i n e are outlined i n the following paragraphs,  1,  Rebuilding the old system would mean that the area was  served by a f i f t y year old system.  still  18 2,  The d i t c h system was designed f o r furrow i r r i g a t i o n which  depended on a p l e n t i f u l supply of cheap labour.  Many farmers had  changed to s p r i n k l e r i r r i g a t i o n and the trend appeared to be toward an increase i n s p r i n k l e r i r r i g a t i o n and a decrease i n furrow i r r i g a t i o n . With the d i t c h system, many small pumps would be required f o r s p r i n k l i n g and i f the cost of pumping were added to that of r e b u i l d i n g the ditches, the t o t a l would be much more than the cost of supplying the water under pressure i n the p i p e l i n e .  In other words, the t o t a l cost of supplying  water to the s p r i n k l e r s would be l e s s with the p i p e l i n e conveyance system than with the d i t c h system,  3.  A d i t c h system i s subject to the ingress of debris and  weeds which tend to c l o g s p r i n k l e r heads unless screening i s undertaken a t the intake.  With the p i p e l i n e system, debris could be removed by  one s e t of screens a t each intake, whereas, with the d i t c h system, each i r r i g a t o r would require a s e t of screens,  4  0  The new system would be constructed of long l a s t i n g  components not exposed to f r o s t or other mechanical damage and hence should have low maintenance c o s t s ,  5«  The water losses of about JO per cent, due mainly to  seepage from canals, would be reduced to almost n i l with the construction of the pipeline system. estimated to be enough to i r r i g a t e  6.  The water saved i n t h i s way was  1500 to 2000 a d d i t i o n a l acres.  During the r e h a b i l i t a t i o n of the o l d system, a l l components  19 with a u s e f u l l i f e of twenty-five  years of l e s s would be  A f t e r that time, f u r t h e r expenditures would be required.  replaced. The p i p e l i n e  system should not require s i g n i f i c a n t c a p i t a l expenditures f o r f i f t y years,  In summary, i t was  f e l t that, from a long term point of view,  the p i p e l i n e system offered the cheapest and best i r r i g a t i o n s e r v i c e . With the p i p e l i n e system, the area could a l s o be served with chlorinated water a t l i t t l e a d d i t i o n a l cost.  This was  an important  consideration as many areas were serviced with shallow wells which probably derived a large amount of recharge from the seepage losses from the canals.  The r e h a b i l i t a t i o n of the system would have tended  to reduce seepage which could have perhaps r e s u l t e d i n dry w e l l s .  Design C r i t e r i a f o r the Pipeline System  Duty.  The water sales records of the Vernon I r r i g a t i o n D i s t r i c t  were studied by the Water Investigations Branch to determine the so-called 'duty' of water f o r the D i s t r i c t ( i . e , the t o t a l depth of water a p p l i c a t i o n i n a season).  I t was  found that there had been a  s l i g h t decline i n t o t a l water demand over the years between 1950 1963 and  and t h i s was  nd  a t t r i b u t e d to the increase i n s p r i n k l e r i r r i g a t i o n  the associated increase i n a p p l i c a t i o n e f f i c i e n c y .  maximum duty of water between 1953 average of 15.O  a  ar  ^d 1963  inches over the i r r i g a t e d  w a s  The  c a l c u l a t e d to be  an  area.  In 1959* a, s o i l survey of the North Okanagan Valley  was  undertaken by the S o i l Survey Branch, B r i t i s h Columbia Department  20 of A g r i c u l t u r e .  The Vernon I r r i g a t i o n D i s t r i c t was divided i n t o s o i l s  areas to compare the water requirements.  Tree f r u i t i r r i g a t i o n demands  are higher than those f o r other types of crops.  Therefore,  to obtain a  maximum f i g u r e f o r water requirements of the area, tree f r u i t demands were used i n the c a l c u l a t i o n s . calculated.  An average duty of 18,3 inches was  The large d i f f e r e n c e with the 15.0 inch f i g u r e c a l c u l a t e d  from records was accounted f o r by the f a c t that large areas such as those growing grain and hay crops were l i g h t l y i r r i g a t e d , thus bringing down the o v e r a l l average.  For design purposes, the duty  assumed by the Water Investigations Branch was an average of 16 inches.  Maximum demand r a t e .  From the D i s t r i c t records i t was •..  calculated that the average maximum demand rate f o r the hottest sixteen day period (July 16 to 31) was 4 , 2 U.S. gallons per minute per acre.  The actual design rate would have to exceed the average maximum  demand rate to meet requirements of areas with above average maximum demand rates and to meet instantaneous peaks.  However, a continued  decrease i n furrow i r r i g a t i o n would tend to reduce the maximum demand rate.  Based on s o i l and consumptive use requirements, the maximum demand rate was calculated to 5*6 U.S. gallons per minute per acre.  Using these f i g u r e s as a guide, the Water Investigations Branch decided  to use 6.0 U.S. gallons per minute per acre f o r the r e h a b i l i -  t a t i o n of the d i t c h system and 5*0 U.S. gallons per minute per acre f o r the p i p e l i n e system f o r purposes of comparing the two systems.  The p i p e l i n e scheme would s u p p l y w a t e r under p r e s s u r e and i t was assumed t h a t w i t h i t , s p r i n k l e r i r r i g a t i o n would be a d o p t e d the  throughout  D i s t r i c t w i t h a r e s u l t a n t l o w e r i n g o f t h e maximum demand r a t e .  As  d e s c r i b e d i n t h e p r e v i o u s s e c t i o n , t h e p i p e l i n e s y s t e m was c h o s e n .  The  f i g u r e o f 5 U.S. g a l l o n s p e r minute p e r a c r e was r e t a i n e d a s a d e s i g n criterian.  Pressure.  The p i p e l i n e system was d e s i g n e d t o p r o v i d e 100 f e e t  o f head o f w a t e r a t t h e o l d c a n a l l e v e l . sufficient  T h i s p r e s s u r e would be  t o i r r i g a t e by s p r i n k l e r s a l l l a n d f o r m e r l y s e r v e d by  g r a v i t y from the o l d system.  OPERATION OF NEW IRBIGATION SYSTEM  Distribution  System  The Vernon I r r i g a t i o n  D i s t r i c t system i s now a n e w l y r e n o v a t e d  s y s t e m c o n s i s t i n g o f a p p r o x i m a t e l y n i n e t e e n m i l e s o f 50 i n c h t o 24 i n c h c o n c r e t e and s t e e l p i p e i n t h e main l i n e  (Figure  3 )•  Branch  l i n e s s e r v i c e e a c h a r e a w i t h l a t e r a l s and o u t l e t s d e l i v e r w a t e r t o each farmer.  The w a t e r i s r e l e a s e d f r o m t h e dam a t Haddo Lake and  f l o w s a p p r o x i m a t e l y f i f t e e n m i l e s down Duteau Greek.  At this  point  a s m a l l d i v e r s i o n dam has been c o n s t r u c t e d w h i c h impounds a b o u t a c r e - f e e t when f u l l .  This r e s e r v o i r i s s u f f i c i e n t  thirty  to supply the  d i s t r i c t f o r f o u r hours and twenty minutes a t maximum demand r a t e o f 38,000 U.S. g a l l o n s p e r m i n u t e . the  main i n t a k e p i p e .  Water i s s c r e e n e d b e f o r e i t e n t e r s  The i r r i g a t i o n w a t e r f r o m t h i s p o i n t i s  23  d e l i v e r e d through a completely closed system.  S i m i l a r l y , water released from King Edward Lake flows down Deer Greek and passes i n t o the system a t a small d i v e r s i o n .  There i s  very l i t t l e storage a t t h i s d i v e r s i o n , so releases from King Edward Lake are c o n t r o l l e d very c a r e f u l l y to avoid wastage.  At the i r r i g a t o r s ' d e l i v e r y point, the D i s t r i c t maintains two valves; both are below f r o s t l i n e .  One opens the l i n e i n t o the stand-  pipe and the other drains the stand-pipe.  At the upper end of the  stand-pipe i s the farm valve owned and maintained by the i r r i g a t o r .  In the spring when the farmer i s ready to s t a r t i r r i g a t i o n , he c a l l s the D i s t r i c t and requests that his water be turned on. An employee of the D i s t r i c t then proceeds to close the d r a i n valve and open the main valve.  From t h i s time to the end of the i r r i g a t i o n  season, the farmer has water "on tap".  He may use the water f o r the  length of time he w i s h e s — o n l y the maximum rate i s f i x e d .  The maximum rate of a p p l i c a t i o n f o r the d i s t r i c t as a whole of 5 U.S. gallons per minute per acre was determined as described i n the previous s e c t i o n .  This rate a l s o applies to the farmer's  i n d i v i d u a l i r r i g a t i o n system.  Each system i s thus designed to use  water a t a rate c a l c u l a t e d on the basis of 5 gallons per minute per acre over the whole acreage.  In practice the water i s applied a t a  much greater rate a t any one time, the area which must be i r r i g a t e d a t any one time depending on the safe i r r i g a t i o n i n t e r v a l which i n turn,  depends on the water holding capacity of the s o i l and the consumptive use.  For example, i f a farmer had a twenty acre p l o t with a safe  i n t e r v a l of ten days, h i s system would be designed to d e l i v e r (20 x  5)  100 gallons per minute , and t h i s would be applied to two acres a t a time i f he operated on a one day cycle or one acre a t a time i f he operated on a twelve hour c y c l e .  Thus, the farmer requires s u f f i c i e n t  equipment to enable him to i r r i g a t e a t l e a s t one acre a t a time.  The  l a r g e r the spread of the equipment, the l e s s frequently i t has to be moved.  In order to c o n t r o l the a p p l i c a t i o n r a t e under varying pressure conditions, the D i s t r i c t requires that a flow c o n t r o l valve be placed under each s p r i n k l e r head.  The flow c o n t r o l valves used i n the  Vernon I r r i g a t i o n D i s t r i c t (Dole type) c o n s i s t of a metal c y l i n d e r with a rubber diaphragm i n s i d e i t .  In the rubber diaphragm i s a hole  arranged such that, as the pressure increases, the s i z e of the hole decreases and the flow decreases.  I f the pressure decreases, the s i z e  of the hole increases, thereby allowing the flow to increase.  In  order to encourage i t s p o l i c y concerning flow c o n t r o l valves, the D i s t r i c t supplies them to the i r r i g a t o r s f r e e of charge.  The D i s t r i c t  p o l i c e s the system and the Water B a i l i f f s have the power to shut o f f the water i f flow c o n t r o l valves have been a l t e r e d or removed.  Operation of the system requires that the p i p e l i n e be kept f u l l a t the headgates d i v e r s i o n a t a l l times by regulation of water releases from Haddo Lake.  This system requires a new  s k i l l on the part  of the Chief V/ater B a i l i f f i n that, since i r r i g a t o r s no longer are  required to order water i n advance, he must now be able to accurately p r e d i c t the water use over the next twelve hour period.  I f too much  water i s ordered from the r e s e r v o i r , i t w i l l s p i l l over the d i v e r s i o n a t the headgates and be wasted.  I f too l i t t l e water i s ordered, the  pipe w i l l empty and pressure l o s s a t the lower end of the system w i l l prohibit i r r i g a t i o n .  When determining the amount of water to order  from Haddo Lake, the Chief Water B a i l i f f considers the weather, the time of year and the time of week,  A change i n weather from cool  to warm or wet to dry would d i c t a t e an increase i n flow.  The time  of year indicates what the i r r i g a t o r s are doing with t h e i r crops. they are s t a r t i n g harvest, they w i l l be stopping i r r i g a t i o n .  If  Variation  i n demand with the time of week i s a phenomenon which has developed with the new system.  For example, a t the Coldstream Ranch, with over  1200 acres under i r r i g a t i o n , the manager has determined that by shutting down i r r i g a t i o n during the weekend, the ranch can save money which otherwise would have to be paid i n overtime to workers moving i r r i g a t i o n pipes, without r i s k to t h e i r crops.  A f t e r balancing a l l the above f a c t o r s the Chief Water B a i l i f f makes an educated guess as to the water demand and orders the water from Haddo Lake,  The water takes approximately eight hours to t r a v e l  from the dam a t Haddo Lake to the headgates and the pond a t the headgates holds enough water f o r about four and one-third hours a t maximum demand,  A d e l i c a t e balance must be maintained i f water  wastage i s to be kept to a minimum  0  For the f i r s t year of operation,  the demand a t the headgates was observed to change r e l a t i v e l y slowly and almost l i n e a r l y during both the increasing and decreasing demand  26 cycle.  This i s probably due to the f a c t that the D i s t r i c t i s so  large that the v a r i a t i o n s caused by i n d i v i d u a l s are i n s i g n i f i c a n t . No problems are a n t i c i p a t e d with p r e d i c t i o n of water demands on a daily basis.  Plans have been made to i n s t a l l an automatic gate system a t the lake o u t l e t when finances permit.  The water l e v e l i n the headgates  pond w i l l be monitored continuously and the gate operation a t the lakes w i l l be radio c o n t r o l l e d . As the l e v e l i n the headgates pond goes down, the control a t the dam can be opened to release more water. This procedure w i l l ensure an adequate supply of water a t the headgates while keeping s p i l l to a minimum.  Also, natural flow from the  uncontrolled portion of the watershed can be u t i l i z e d more r e a d i l y . However, i n view of the l i m i t e d storage a t the d i v e r s i o n of only about four hours supply and the time of t r a v e l of eight hours from the r e s e r v o i r , very c a r e f u l design w i l l be necessary.  Reservoir System The Vernon I r r i g a t i o n D i s t r i c t has four storage r e s e r v o i r s as shown i n Figure  k.  Aberdeen, the l a r g e s t , drains d i r e c t l y i n t o  Haddo Lake which i s much smaller i n storage volume (Table I I I ) . From Haddo Lake water i s released i n t o Duteau Creek and a f t e r t r a v e l l i n g about f i f t e e n miles, can be diverted i n t o the Vernon I r r i g a t i o n D i s t r i c t i r r i g a t i o n scheme a t the d i v e r s i o n dam a t Headgates,,  I f the  water i s not diverted, i t continues down Duteau Creek and eventually i n t o the Fraser Watershed,  About seven and one h a l f miles to the west  28 l i e s King Edward Lake  0  The water from t h i s lake flows down Deer Creek  to a d i v e r s i o n dam and then, i f i t i s not diverted i n t o the i r r i g a t i o n scheme, t h i s water flows i n t o Kalamalka Lake.  The l a s t storage lake  i s Goose Lake, a balancing r e s e r v o i r on the north-west side of the District. of 1275  Goose Lake has l i t t l e natural inflow but has a l i v e storage  acre-feet.  TABLE I I I  CATCHMENT AREA, STORAGE, AND GOVERNING WATER LEVELS OF VERNON IRRIGATION DISTRICT RESERVOIRS (5)  RESERVOIR  CATCHMENT AREA SQ. MI.  LIVE STORAGE AC. FT.  WATER ELEVATIONS FEET (GEODETIC) MAX. MIN.  Aberdeen Lake Haddo Lake King Edward Lake Goose Lake  20.7 19.2 4.6  8,693.6 2,498.3 1,253.5 1,275.0  4,196.0 4,167.1 4,485.0 1,637.0  Negligible  SURFACE AREAS ACRES MAX. MIN.  4,172.0 576.2 4,146.6 176.3 4,465.0 82.3 1,617.0 89.0  112.0 30.0 ^7.0 47.0  The D i s t r i c t I r r i g a t i o n Manager-Engineer has the r e s p o n s i b i l i t y f o r operation of the r e s e r v o i r s and the main c r i t e r i a used to operate the dams i s that there i s maximum carry over, f o r insurance against drought next season.  At the end of the i r r i g a t i o n season, the lake outlets are closed and remain closed u n t i l the beginning of the next i r r i g a t i o n season (except f o r domestic water releases from Haddo Lake), During the spring freshet, there i s seldom s u f f i c i e n t run-off to completely  29 f i l l Aberdeen Lake since i t has a large storage volume i n comparison to i t s watershed area. but  King Edward Lake sometimes f i l l s and s p i l l s  not as often as Haddo Lake which almost always s p i l l s large  amounts of water.  In order to use some of the spilled, water, i t i s  channelled to Goose Lake through the i r r i g a t i o n system and may f i l l Goose Lake before the i r r i g a t i o n demand has become s u b s t a n t i a l . pattern of r e s e r v o i r releases i s as f o l l o w s :  during the f i r s t  The part  of the i r r i g a t i o n season while the demand i s r e l a t i v e l y low, water i s drawn from Haddo Lake which i s r e f i l l e d from Aberdeen Lake as necessary. the  As the demand increases King Edward Lake i s tapped. At  peak demand of the season Goose Lake i s a l s o opened and a l l  inputs into the system are used.  The i d e a l s i t u a t i o n a t the end of the i r r i g a t i o n season i s to have Goose and Haddo Lakes empty, some carry over i n King Edward Lake and as much carry over as possible i n Aberdeen Lake, procedure i s i l l u s t r a t e d i n Figures 5  a  n  (  l 6 .  The above  The hydrographs shown  have been derived from recorded discharges i n B.X. Greek i n 19&7 since d e t a i l e d records of inflow i n t o the lakes are not a v a i l a b l e .  B.X,  Creek, has the same general watershed c h a r a c t e r i s t i c s as the lakes i n the  Vernon I r r i g a t i o n D i s t r i c t and the hydrograph shown i s believed  to be reasonably representative.  The v e r t i c a l l i n e s show that the  r e s e r v o i r i s f u l l and the inflow i s transmitted d i r e c t l y to outflow. For  example, on May 18, (Figure 5) Haddo Lake was f u l l and the water  was diverted to Goose Lake.  On June 21, the outflow from the watersheds  became l e s s than the i r r i g a t i o n demand. to be released to s a t i s f y the demand.  Therefore, storage water had On July 15, a l l the r e s e r v o i r s  30 IS  HADDO L A K E  2S  KING EDWARD L A K E  3S 4S  5S  60  6  STORAGE STORAGE  GOOSE L A K E STORAGE GOOSE L A K E ABERDEEN SPILL  STORAGE  LAKE  FROM  STORAGE  KING  EDWARD  LAKE R  140  HADDO  LAKE  RELEASE  2R  KING EDWARD L A K E  3R  GOOSE L A K E  5R  ABERDEEN  120  ABERDEEN  RELEASE  RELEASE  LAKE  RELEASE  LAKE  CARRY-OVER  I300ac.ft.  HADDO,KING EDWARD  100  co u.'  o  80  AND  ABERDEEN  LAKES  HADDO AND KING EDWARD LAKES  RRIGATION DEMAND  5 o  60 HADDO L A K E  40  20  MARCH  APRIL  MAY  Fig.5  HYDROGRAPHS OF L A K E  IN HIGH FLOW  JUNE  YEAR .  JULY  AUGUST  INFLOW AND  SEPTEMBER  RELEASE  31  60  IS  HADDO L A K E  2S  KING EDWARD L A K E S T O R A G E  STORAGE  3S  GOOSE L A K E  STORAGE  4S  GOOSE L A K E  STORAGE  5S  ABERDEEN HADDO  LAKE  LAKE  STORAGE  RELEASE  KING EDWARD L A K E GOOSE L A K E  140  ABERDEEN RELEASE  RELEASE  RELEASE  LAKE  RELEASE  OF A B E R D E E N  LAKE  C A R R Y - OVER _  120  to u. (J _  100  HADDO, KING EDWARD AND A B E R D E E N LAKES  ? o _i  u.  IRRIGATION DEMAND  80  60  -  40  -  HADDO AND KING EDWARD LAKES  20  MAY  JUNE  JULY  AUGUST  MARCH  APRIL  Fig.6  HYOROGRAPHS OF L A K E INFLOW IN LOW FLOW YEAR .  SEPTEMBER  AND R E L E A S E  32  were contributing to the peak i r r i g a t i o n demand.  During any one year, the t o t a l demand might be l a r g e r than the t o t a l inflow to the lakes.  The carry over from the previous year  would then be used to s a t i s f y the demand (Figure  6 ).  In the year  i l l u s t r a t e d i n Figure 5 the t o t a l demand was l e s s than the t o t a l inflow so there was carry over f o r the next year.  33  CHAPTER IV  SCHEDULING THE APPLICATION OF WATER  Scheduling of i r r i g a t i o n means the a p p l i c a t i o n of the c o r r e c t amount of water a t the time when i t i s needed by the s o i l (17).  The  objective of scheduling i s to maintain the s o i l moisture content within an optimal range, while applying as l i t t l e water as possible. Since scheduling o f f e r s one of the main opportunities f o r economising on the use of water, i t i s considered i n some d e t a i l i n the following sections.  EQUIPMENT USED IN SCHEDULING  The most common method of scheduling used i n the Okanagan Valley was evolved by Dr. Wilcox, of the Summerland Research Station who named i t the "Balance Sheet" method. method consists of a balance sheet (Figure evaporimeter.  The equipment f o r t h i s 7 ), a r a i n gauge and an  The Black Belanni Plate evaporimeter, (Figure 8) was  introduced to Canada i n 1957  a n  d met a l l but one of the requirements  f o r use i n the Okanagan? i t uses water as an evaporating medium and the water froze i n the spring and f a l l as the temperature dipped a t higher s i t e s along the v a l l e y w a l l .  The evaporimeter was sometimes  damaged, and the records were l o s t f o r the period while the evaporimeter was frozen.  Dr. Wilcox developed an evaporimeter e s p e c i a l l y f o r use  i n the Okanagan Basin and termed i t the "Ogopogo" evaporimeter  Figure 7. Grower:  BALANCE SHEET John Doe  Safe I r r i g a t i o n I n t e r v a l :  Date  Water Use  Rain  Month: 6  Credit Depth  1.68  days  Credit Depth:  Balance  1.48  1  .20  2  .24  1.24  3  .25  .99  4  .19  .80  5  .19  .61  6  .25  .36  7  .18  8  .23  9  .26  10  .16  11  .16  May, 1964 1.68  inches  i Started i r r i g a t i n g 7 a.m.  Finished i r r i g a t i n g 7 a.m.  .34 .11 1.42  Started i r r i g a t i n g 7 a.m.  .20  1.42  Raining  .08  .23  1.42  Raining  12  .10  .15  1.42  Raining  13  .18  .06  1.30  14  .28  1.02  15  .23  .79  16  .10  17  .22  .80  18  .30  .50  19  .30  .20  20  .30  -.10  Stopped f o r mowing  21  .25  1.33  Started i r r i g a t i n g 7 a.m.  22  .30  1.03  23  .28  .75  24  .25  .50  25  .26  .24  26  .27  -.03  Finished i r r i g a t i n g 7 a.m.  27  .20  1.45  Started i r r i g a t i n g 7 a.m.  28  .15  1.30  29  .20  1.10  30  .20  .90  31  .25  .65  1.68  1.02  .50  1.68  1.68  Finished i r r i g a t i n g 7 a.m.  ( R a i n f a l l credited to balance on May 1*)  Balance of .65 carried over to June  35 (Figure 9) (l6). The evaporating surface i s the end of a c y l i n d r i c a l carborundum block approximately 5  c m  « i  n  diameter and 6.6 cm. long  which has been placed i n a bottomless polyethylene b o t t l e .  A tube leads  from the b o t t l e to the r e s e r v o i r which has a capacity s u f f i c i e n t to supply the evaporimeter with l i q u i d f o r the period between readings.  A  glass s h i e l d ten to twelve inches i n diameter i s placed three inches above the evaporating surface to protect i t from r a i n .  The evaporating  l i q u i d used i s a mixture of methanol and d i s t i l l e d water which does not freeze u n t i l the temperature  reaches about 10°F.  The r a i n gauge may  be of any type, but the commercially made wedge-shaped p l a s t i c model i s the most popular.  GENERAL PROCEDURE When the i r r i g a t i o n i s started, the appropriate c r e d i t depth i s added to the balance on the sheet.  Each day thereafter, the balance  sheet i s debited with the amount of water used by the crop which i s estimated from the evaporation measured by the evaporimeter. i r r i g a t i o n cycle i s completed  I f the  before the balance on the sheet reaches  zero, the s p r i n k l e r l i n e s are shut down and l e f t i d l e u n t i l the balance reaches zero.  At t h i s point, the next i r r i g a t i o n i s started and the  balance sheet credited with the amount of water a p p l i e d .  The balance sheet shown (Figure 7) i s f o r a p l o t of land with an i r r i g a t i o n i n t e r v a l of s i x days and a c r e d i t depth of 1,68 inches. The depth of a p p l i c a t i o n would be determined by multiplying the c r e d i t depth by a f a c t o r which accounts f o r the a p p l i c a t i o n e f f i c i e n c y .  In  Figure  8  . B e l l a n i Plate  Evaporimeter  Figure  9 «  Evaporimeter  Ogopogo  the i l l u s t r a t i o n , i r r i g a t i o n was begun on panel one on the f i r s t of May.  This i s the panel f o r which the s o i l moisture balance was  The farmer then added the 1.68  kept.  inches to the previous balance,  subtracted the water use or evapotranspiration f o r that day, and entered the balance ( i . 4 8 ) .  I r r i g a t i o n continued with the l i n e s being changed  every twelve hours and, each day, the water use was subtracted from the previous balance to show how much water was l e f t i n the s o i l i n panel one.  At the end of the s i x t h day, one i r r i g a t i o n cycle  completed and the balance sheet showed that there was s t i l l (O.36") i n the s o i l .  was  moisture  The system was shut down and the i r r i g a t o r waited  u n t i l the balance sheet reached an amount approximately equal to the d a i l y water use, whereupon he started i r r i g a t i n g again.  CREDIT FOR RAIN When r a i n occurs, any unsaturated panel benefits, but can only hold a d d i t i o n a l water up to f i e l d capacity.  When a panel i s i r r i g a t e d ,  i t s moisture content i s r a i s e d to f i e l d capacity, and therefore, r a i n occurring on that same day can be counted only up to the amount of evapotranspiration occurring while the panel i s being i r r i g a t e d .  In  order to take f u l l advantage of r a i n , a budget would be needed f o r each panel i n the f i e l d .  In p r a c t i c e , however, a budget i s kept f o r only one panel of the f i e l d rather than each i n d i v i d u a l panel. set  Therefore, an elaborate  of r u l e s has evolved to ensure that the f i e l d does not dry to the  point where crops are damaged.  With t h i s system, i f i r r i g a t i o n i s  38 i n progress, c r e d i t i s only given f o r r a i n up to the evapotranspiration f o r the day; any more c r e d i t could cause an unwarrented delay i n s t a r t i n g the next i r r i g a t i o n which could r e s u l t i n excessive drying of the s o i l a t some point i n the f i e l d during the next i r r i g a t i o n .  When no i r r i g a t i o n i s i n progress, c r e d i t f o r r a i n can be given only up to the balance on the sheet a t the time when the l a s t i r r i g a t i o n c y c l e was completed.  Between i r r i g a t i o n c y c l e s the whole  f i e l d receives b e n e f i t from the r a i n . receives the l e a s t b e n e f i t ; i n f a c t , point.  The wettest part of the f i e l d only up to f i e l d capacity a t that  The wettest part i s , of course, the s o i l a t the l a s t point  i r r i g a t e d , and f i e l d capacity there i s represented  by the balance a t  the f i r s t s e t t i n g , as shown on the balance sheet a t cessation of irrigation.  Giving more c r e d i t than t h i s f o r r a i n could cause an  unwarrented delay i n the s t a r t of the next i r r i g a t i o n ( 1 9 ) ,  These r u l e s are i l l u s t r a t e d on the balance sheet (Figure 7 ) . On the tenth, r a i n amounted to 0.20 inches, 0,04 inches more than the evapotranspiration.  Even so c r e d i t f o r that r a i n could be given only  to the balance on the previous day, (1.42") as i r r i g a t i o n was i s progress.  The same a p p l i e s to the r a i n which occurred on the eleventh  and twelfth. occurred.  On the sixteenth, i r r i g a t i o n was not i n progress and r a i n  C r e d i t f o r t h i s r a i n was given up to the l e v e l or balance  on the day that i r r i g a t i o n ceased  (l,02).  39  CHOOSING A SITE FOR THE EVAPORIMETER Evapotranspiration from a small irrigated plot i s greater when the plot i s surrounded by dry unirrigated land than when i t i s i n the middle of a large irrigated area.  This i s due to the advection of heat  from the surrounding dry land and i s sometimes referred to as the "oasis effect".  In the Okanagan, a high proportion of the irrigated land  abuts or l i e s close to dry land and i n these circumstances placing the evaporimeters i n the centre of the irrigated land would give readings too low to represent the very long marginal areas.  Evaporimeters  placed on dry land often show much higher rates of evaporation than those placed within an irrigated area and hence cannot represent conditions over the irrigated land satisfactorily.  A reasonable  compromise i s a site chosen near the edge of the irrigated land where i t adjoins dry land or in a small non-irrigated plot within the irrigated area.  In any case, the evaporimeters must be placed where  they do not receive water from the sprinklers.  SCHEDULING FOR IRRIGATION DISTRICTS Some  Irrigation Districts operate evaporation stations for the  use of irrigators throughout the d i s t r i c t .  In this case the evapori-  meters must be located so that the readings w i l l represent the driest irrigated area within the d i s t r i c t .  This means that some orchards w i l l  receive excess water, but at least a l l orchards should receive enough. The problem of orchards receiving too much water can only be solved by installing more evaporimeters.  40 The D i s t r i c t evaporimeters are read by an employee and the water use f i g u r e s are posted on a b u l l e t i n board on the side of a road t r a v e l l e d frequently by the i r r i g a t o r s .  I r r i g a t o r s copy the f i g u r e s  and keep the balance sheet f o r t h e i r own orchards.  One improvement  which might be applied to the system i s the i n s t a l l a t i o n of an automatic telephone answering s e r v i c e .  The evaporation readings could  be read i n t o a tape recorder and i r r i g a t o r s would only need to d i a l the appropriate telephone number to obtain the evapotranspiration f i g u r e s , which they need to keep t h e i r own water balance.  ADVANTAGES OF SCHEDULING  The main advantage of scheduling i s that i t permits maximum use of the a v a i l a b l e water resources. 1.  Other benefits i n c l u d e :  Water wastage i s reduced to a minimum which r e s u l t s i n  lower pumping costs, reduced seepage and l e s s leaching of nutrients from the s o i l . 2.  Less time i s spent i r r i g a t i n g ; t h i s saving i n time may  amount to as much as 10% i n the Vernon area, 3.  In c o o l or r a i n y weather, i r r i g a t i o n can be discontinued  without f e a r of damage to crops due to l a c k of water, 4.  As the same amount of water i s applied a t each i r r i g a t i o n ,  the design features of the system may be standardized  (nozzle s i z e ,  pressure, length of s e t ) . 5.  The i r r i g a t o r can have greater confidence and peace of mind  knowing h i s crop w i l l not s u f f e r because of lack of water. advent of scheduling, some i r r i g a t o r s  Before the  shut down during wet or cool  weather "but they worried about the damage that could occur i f they did not s t a r t i r r i g a t i n g soon enough. With scheduling, they can be confident that no damage w i l l r e s u l t to their crops.  PROBLEMS WITH SCHEDULING Scheduling as i t i s practised, using a simple budget f o r a farm rather than a budget f o r each panel involves the assumption that the weather remains constant or changes only gradually. Weather however, i s not always so co-operative and some w i l t i n g of the crop can occur i f precautions are not taken (Figure 10'),. As an example, assume that an orchard requires two inches of water every ten days i n the heat of summer. This means that the average peak evapotranspiration i s 0.20 inches per day.  I f during cool weather i n June, the average evapo-  transpiration happens to be only 0.10 inches per day the grower who l s using the balance sheet procedure finishes his i r r i g a t i o n and waits for ten days before starting to i r r i g a t e again.  I f the weather then  turns hot and the average evapotranspiration becomes 0,20 inches per day, by the time the l a s t part of the orchard i s i r r i g a t e d , the s o i l there contains 1.00 inch less water than i t had the l a s t time when i t was irrigated and the s o i l water d e f i c i t now i s 3.00 inches.  I f the  s o i l i s now given the standard application of two inches, a d e f i c i t of one inch w i l l remain.  The d e f i c i t can be cumulative over the i r r i g a t i o n  season and could build up to the point where the crops could be permanently damaged. In order to avoid this d i f f i c u l t y the rule was developed that i r r i g a t i o n must be started when the available water content a t the starting point f a l l s to 60%,  In the example cited this  TEMPERATURE  BELOW  TEMPERATURE  AVERAGE  PRECIPITATION ABOVE  o  cn to  £. U  0.20  UJ  o o o o  o o O o o o o o oo o o o o oo O 00 O O o o o o  o  O  000  o  o  o  o  0.10  May I  o oo Oo 00 o coo O o o o o o o 00 o o o o o o o o o o o 00 oo o 00 o 00 o o o o o  Fig. 10  June I  DAILY  15  July 1  EVAPOTRANSPIRATION  o o  o  o  oo o  o  oo o oo o  o  o  o o  o  °u ° o o o o o o o o o o| o o 00  00  J.  15  AVERAGE  AVERAGE  0.30  1  ABOVE  15  August I  15  AT S U M M E R L A N D  September I  R E S E A R C H  15  STATION, 1971 .  •p-  43 would allow the water content j u s t before i r r i g a t i o n to f a l l to as low as  of the s o i l moisture storage, a value which does not seem to  damage f r u i t trees, although shallow rooted cover crops may w i l t occassionally,  USE OF SCHEDULING Although the "Balance Sheet" method of scheduling has been developed to a very sophisticated state, r e l a t i v e l y few of the growers i n the Okanagen Valley are using i t .  Some growers have t h e i r own s e t  procedure which they f e e l i s s a t i s f a c t o r y , and they see no need f o r change.  Some are not suited by temperament or education to the keeping  of balance sheets and r e g u l a t i n g t h e i r i r r i g a t i o n accordingly.  Perhaps  some i r r i g a t o r s f e e l that a p l e n t i f u l supply of water i s a natural r i g h t i n h e r i t e d from t h e i r forefathers and see no need f o r conservation. Some, c e r t a i n l y , are not aware of the need f o r conservation nor of the  a v a i l a b i l i t y of scheduling procedures. Also, the present "tax"  method of payment f o r i r r i g a t i o n service does not encourage farmers to save water since under t h i s system farms f o r which water service i s maintained, must pay a f l a t rate whether of not the maximum allowable water i s used.  The minimum requirement of an i r r i g a t i o n  system i s that i t i s designed to cover the f i e l d with s u f f i c i e n t i r r i g a t i o n water during the one or two weeks of hottest weather i n summer.  Some growers turn on the water i n the spring and run t h e i r  system a l l season a t the maximum r a t e .  Therefore, f o r most of the  year, water i s being applied a t a rate i n excess of the evapotranspiration rate.  This water as well as being wasted, leaches nutrients  44 such as nitrogen and boron from the s o i l , nutrients which not only are expensive to replace but a l s o can cause water q u a l i t y problems i n the water down stream from the i r r i g a t o r ' s f i e l d .  The cost of s e t t i n g up an i n d i v i d u a l evaporimeter s t a t i o n i n  1971 i s l e s s than $50*00 and Department of Agriculture and Summerland Research Station personnel are always a v a i l a b l e and w i l l i n g to a s s i s t with the i n s t a l l a t i o n .  At the time of writing evaporimeters were  supplied from the Research Station and r a i n gauges were obtained l o c a l l y from a commercial source.  45  CHAPTER V  ADDITIONAL USES OF DUTEAU CREEK  FISHERIES  Paxt of Duteau Creek, "below the Vernon I r r i g a t i o n  District  d i v e r s i o n , provides a spawning and r e a r i n g area f o r P a c i f i c Salmon (Figure 11).  As many as two thousand Chinook have been known to spawn  i n Duteau Creek ( 2 3 ) .  A constant supply of clean water i s c r i t i c a l  i n the l i f e cycle of the salmon.  The adults l a y t h e i r eggs i n gravel  on the creek bed i n the f a l l of the year.  I t i s necessary to have an  adequate flow of water over the gravel so that the eggs w i l l be provided with enough oxygen through the winter.  In the spring, the  eggs hatch and the young f i s h remain i n the f r e s h water system f o r one year and then they migrate to the ocean.  When they are three to seven  years o l d , the salmon return to the stream from which they originated, to spawn and d i e .  During the spawning season, enough water must be  provided to allow the f i s h to swim and spawn.  I f the f i s h population i s to be maintained there must be a year round supply of water below the Vernon I r r i g a t i o n d i v e r s i o n (Figures 12  and  13 ).  District  The o l d V.I.D. d i v e r s i o n dam i s  reported to have leaked badly enough so that s u f f i c i e n t water escaped down stream to maintain the f i s h population.  With the erection of the  new watertight d i v e r s i o n dam, the water w i l l have to be released i f the f i s h population i s to be maintained. The Canada Department of F i s h e r i e s  46  F i g . II  FLOODING A N D SPAWNING W A T E R S H E D .  LOCATION  IN  D U T E A U  C R E E K  F i g . 12 DISCHARGE IN DUTEAU CREEK BELOW THE VERNON D I V E R S I O N , LOW F L O W Y E A R , 1 9 6 3 .  IRRIGATION  DISTRICT  18 23 28 3 APRIL  Fig.13  8  MAY  13 18 23 28 3 JUNE  13  23  3 JULY  13  23  3  13  AUGUST  DISCHARGE IN DUTEAU C R E E K BELOW T H E VERNON DISTRICT DIVERSION, HIGH FLOW Y E A R .  23  3  13  SEPTEMBER  IRRIGATION  49 i n Vancouver estimated flow requirements periods while 7.0  a t 4.0  c f s . during non-spawning  c f s . are required f o r four months (September through  December) during spawning,. (23).  This amounts to 36OO acre f e e t per  year which represents 26% of the t o t a l storage capacity of Vernon Irrigation District.  FLOOD PROTECTION AT LUMBY  Approximately  seventeen miles east of Vernon i s the small town  of Lumby, where the main economic a c t i v i t i e s are c a t t l e ranching and wood processing.  The town has suffered i n the past from f l o o d damage  from the combined e f f e c t of high flows i n Bassette and Duteau Creeks. The main concern has been the l o s s of employment f o r approximately twenty-five men f o r two weeks per year while a sawmill i s rendered inoperable by high water.  The Water Investigations Branch of the  B r i t i s h Columbia Department of Lands, Forests and Water Resources has studied the problem, recommended channel improvements and proceeded with the necessary construction.  The estimated c o s t of the project was  $46,000,00 and the design peak d a i l y discharge was 650 c f s . c o r r e s ponding to a f l o o d with a return period of 50 years (2).  For the  present, i t appears that Lumby i s out of danger from floods from the two creeks.  However, i n the face of increasing population and lack of  zoning, there i s l i t t l e doubt that problems w i l l a r i s e i n the f u t u r e . Therefore, the problem of f l o o d i n g i n Lumby should be included i n any comprehensive plan f o r increased c o n t r o l of water from Duteau Watershed.  50  CHAPTER VI  PLANS FOR THE FUTURE At  the present time, there i s some minor c o n f l i c t over the use  of water from Duteau Creek and i t i s probable that t h i s c o n f l i c t w i l l increase i n the coming years unless remedial measures are undertaken. Two obvious types of s o l u t i o n to t h i s water resource problem are construction o f a d d i t i o n a l storage and better management of the e x i s t i n g system.  CONSTRUCTION OF ADDITIONAL STORAGE This has been the t r a d i t i o n a l s o l u t i o n to water shortage problems, perhaps because the engineering profession has h i s t o r i c a l l y been commissioned to solve problems by construction of new  facilities.  Studies have already been made of constructional measures to increase water a v a i l a b i l i t y i n Vernon I r r i g a t i o n D i s t r i c t .  Present dams could  be enlarged and new dams could be b u i l t to hold more of the spring f r e s h e t waters from snowmelt.  The Haddo Lake watershed a l s o has a  unique feature which could be u t i l i z e d to produce another water saving project.  Haddo Lake watershed i s divided i n t o two d i s t i n c t p a r t s j  that which drains f i r s t i n t o Aberdeen Lake, and that part of the watershed which drains d i r e c t l y i n t o Haddo Lake without f i r s t passing through Aberdeen Lake (Figure i l ) .  These two areas are each approximately  twenty square miles and would be expected to produce approximately the  same amount of r u n - o f f  0  Aberdeen i s usually capable of containing  51 all  the run-off from i t s watershed and i n f a c t r a r e l y f i l l s .  Haddo  Lake however, has only about one quarter the storage volume and as a r e s u l t the lake f i l l s and then much of the f r e s h e t water i s s p i l l e d and, from the point of view of i r r i g a t i o n , i s wasted.  The topography  of the watershed lends i t s e l f to the construction of a canal which would take water from the G r i z z l y Swamp area, which would o r d i n a r i l y d r a i n d i r e c t l y i n t o Haddo Lake, and convey t h i s water to Aberdeen Lake thus u t i l i z i n g more of the storage volume a v a i l a b l e a t Aberdeen Lake. Increasing the height of the Haddo Lake dam i s l e s s f e a s i b l e as t h i s would involve a number of saddle dams around the perimeter of the storage area,  MANAGEMENT The second method of s o l v i n g the water conservation problem involves better management. all  Many suggestions have been made but  involve some s p e c i a l problems and before these suggestions can  be Implemented, the problems must be resolved.  These problems are  examined i n the f o l l o w i n g s e c t i o n .  Economic Incentive Economists show that the consumption of a commodity decreases as i t s cost increases.  This could be applied to i r r i g a t i o n water i n  the Vernon I r r i g a t i o n D i s t r i c t by the implimentation water.  In 1971,  $27.00 per acre.  of a u n i t cost f o r  the tax f o r i r r i g a t i o n water service i n V.I.D. was This i s rather i n s i g n i f i c a n t when compared to the  annual prunning, spraying, p i c k i n g and other costs which are estimated  52 at  $300.00 per acre.  However,  $27.00 i s s i g n i f i c a n t l y greater than the  $2,00 to $5.00 per acre per year charged to i r r i g a t o r s i n other parts of Canada and an increase i n the c o s t of water might r a i s e the farmers' annual costs above annual revenue thereby squeezing presently operating on a small p r o f i t margin.  out those  Unemployment i s already a  problem and the cost of supporting unemployed farmers could be much greater than possible gains from higher charges. i n the 1965 be  Also, i t was  estimated  r e p o r t that the cost of water-meters f o r a l l users would  $150,000.00. Changing to a d i f f e r e n t form of charging f o r water use  could create severe s o c i a l problems and would require a major change i n government p o l i c y .  I t seems that such a change could not be q u i c k l y  brought about.  Extra Equipment Under some circumstances, equipment he can conserve water.  i f an i r r i g a t o r purchases extra Extra equipment allows the i r r i g a t o r  to cover h i s f i e l d i n a shorter time i n t e r v a l and t h i s means he can shut down h i s l i n e s while the weather i s c o o l or wet, but, i f there i s a sudden change to hot dry weather, he can s t i l l i r r i g a t e the whole farm before the s o i l drys out too much.  In Vernon I r r i g a t i o n D i s t r i c t ,  however, the maximum d e l i v e r y rate to a farm i s set a t 5 U.S. per minute per acre.  gallons  Extra equipment would be of l i t t l e advantage  since lower a p p l i c a t i o n rates would have to be used i n conjunction with extra equipment thus lengthening the time f o r each a p p l i c a t i o n .  53 Better Operation of Reservoirs At present the Vernon I r r i g a t i o n D i s t r i c t operates two snow courses i n the Haddo Lake watershed.  These y i e l d r e s u l t s which t e l l  whether t h i s run-off w i l l be greater or l e s s than usual but do not give precise estimates of the expected run-off.  Therefore, the  r e s e r v o i r s are operated with l i t t l e knowledge of the inflow which w i l l occur.  I f b e t t e r hydrologic data were a v a i l a b l e to the manager of the  d i s t r i c t , the lakes could be operated to obtain maximum use of a v a i l a b l e water f o r a l l resource users.  However, techniques w i l l have to be  perfected and hydrologic s t a t i o n s i n s t a l l e d i n the area before t h i s type of management can become a r e a l i t y .  Scheduling This method of determining the precise time i r r i g a t i o n i s required, holds promise of water conservation i n the Okanagan V a l l e y . The biggest problem i s to get the i r r i g a t o r s to use i t .  Teaching  programs so f a r have proved unsuccessful i n inducing large numbers of i r r i g a t o r s to switch to scheduling. water conservation.  Perhaps few people see the need f o r  However, i t i s not hard to v i s u a l i s e the v a l l e y  divided i n t o zones by evapotranspiration r a t e s , and d a i l y water use f i g u r e s f o r farmers use published i n newspapers, included with farm news and a v a i l a b l e by telephone. of  the Ogopogo evaporimeter  At present, no commercial production  i s underway and the only models a v a i l a b l e  have been those produced by Summerland Research S t a t i o n .  Also,  extension personnel i n the v a l l e y are probably already too overworked to introduce and back up a s i g n i f i c a n t scheduling education program.  Drip  Irrigation Research i s currently underway a t the Summerland Station on  a new type of i r r i g a t i o n system.  The system u t i l i z e s small diameter  ( l / l 6 " to l/32") tubes c a l l e d "drippers", as a method of d e l i v e r i n g the water to the trees.  The i r r i g a t i o n water i s delivered to the f i e l d  i n the conventional manner but perhaps a t a lower pressure.  Plastic  tubing of two to three inch diameter i s then used to d e l i v e r the water near the t r e e s — p r o b a b l y between every second row of trees. water then enters a dripper which takes i t to a header.  The  Prom the  header, drippers lead to between f i v e and ten points around the tree to d e l i v e r the water to the s o i l where i t w i l l be quickly picked up by the r o o t s .  With d r i p i r r i g a t i o n , the whole f i e l d i s i r r i g a t e d a t the  same time.  SUMMARY The problems and c o n f l i c t s of the water resource users of Duteau Greek watershed  seem  l i k e l y to increase i n the f u t u r e .  Alternative  solutions of these problems a t the system l e v e l include construction of more r e s e r v o i r s , construction of a d i v e r s i o n canal, and improved management of the e x i s t i n g system i n a number of ways.  There may be  room f o r better r e s e r v o i r operation but the need f o r better hydrologic data w i l l have to be s a t i s f i e d f i r s t , and the implementation w i l l involve l e a r n i n g more about the hydrology of the area and about the system as a whole.  There i s a l s o some oportunity f o r conserving water  through scheduling which involves learning a t the farmer l e v e l .  It  seems that management of the system should be looked on p a r t l y as a  55 l e a r n i n g process which w i l l allow both the system managers and the farmers to a n t i c i p a t e t h e i r problems, understand the opportunities and a l t e r n a t i v e s , and deal with problems i n good time.  56  CHAPTER VII  CONCLUSIONS This study has examined the Vernon I r r i g a t i o n D i s t r i c t , the l a r g e s t i r r i g a t i o n d i s t r i c t i n the Okanagan V a l l e y , and one which has r e c e n t l y been modernized.  The o l d system has served the residents well  and i t i s to be hoped that the new one w i l l serve equally w e l l .  Reasons  f o r the s e l e c t i o n of the new system, design c r i t e r i a , and d e t a i l s of the operation of the system have been given i n the hope that they may prove valuable to designers of future systems, farmers and i r r i g a t i o n managers.  As water demands continue to grow, management problems w i l l become more complex and w i l l require more accurate information about the a v a i l a b i l i t y and use of water f o r t h e i r s o l u t i o n .  New  multi-use  management p o l i c i e s w i l l have to be formulated to include n o n - i r r i g a t i o n demands.  Eventually, i t may be necessary to construct a d d i t i o n a l  storage f a c i l i t i e s and a l s o perhaps to induce the farmers to conserve water.  Water can be conserved by scheduling, and the problems and  p o t e n t i a l of t h i s process have been examined i n some d e t a i l .  Before  i t can be widely adopted, however, there w i l l have to be an extensive l e a r n i n g program, not only on the part of the i r r i g a t o r s , but a l s o on the part of the planners and system managers.  Also new  techniques  such as d r i p i r r i g a t i o n which w i l l make water conservation e a s i e r may be developed,  provided there i s continued research i n i r r i g a t i o n .  57  B I B L I O G R A P H Y  1.  2.  3.  B r i t i s h Columbia. Department of A g r i c u l t u r e . Irrigation Guide. V i c t o r i a , B.C.  British  Columbia  . Department of Lands, Forests and Water Resources. Water Resources Service. Preliminary Report. Corporation of the Village of Lumby Flood Protection. V i c t o r i a , 1969.  . Water Act and Regulations.  1968.  4.  Canada. Department of A g r i c u l t u r e . Farming in the Vernon Irrigation District. Unpublished Report. Ottawa, Canada. 1963.  5.  F u l l e r , J . D. C. Vernon Irrigation District Engineering Study. Department of Lands, Forests and Water Resources. V i c t o r i a , 1965.  6.  G a b r i e l , Theresa. A Brief History of Vemon Committee, Vernon, B.C. 1958.  «  L i n s l e y , R. K., M. A. Kohler and J . L. H. Paulhus. Hydrology for Engineers. Toronto: McGraw H i l l Co. Inc., 1958.  7  3  B.C. Vernon Centennial  8.  MacKenzie, A. R. Report of the Coldstream Report. Vancouver, 1913.  9.  O'Riordan, J . " E f f i c i e n c y of I r r i g a t i o n Water Use." Unpublished Doctor's D i s s e r t a t i o n , University of B.C., 1969.  10.  11.  Estate.  Consulting  Engineer's  Pennington, D. J . North Okanagan Irrigation and Domestic Water Supplies. V o l . I, Irrigation Water Supplies. B.C. Department of Lands, Forests and Water Resources, V i c t o r i a , 1961.  . North Okanagan Irrigation and Domestic Water Supplies. V o l . I I , Domestic Water Supplies. B.C. Department of Lands, Forests and Water Resources, V i c t o r i a , 1961.  53 13.  R u s s e l l , S. 0., M. C. Quick and W. D. Finn. Water Resources of the Nicola-Kamloops Area: Preliminary Appraisal. Report No. 1 , U n i v e r s i t y of B r i t i s h Columbia, Vancouver, 1 9 6 9 .  14.  Schwab, 0. S. and others. Soil New York: Wiley, 1 9 6 6 .  15.  Spence, C. C. An Appraisal Irrigation District. Ottawa, 1 9 6 4 .  16.  Vernon Irrigation  17.  Wilcox, J . C. "A Simple Evaporimeter f o r use i n Cold Areas," Water Resources Research^ V o l . 3, No. 2 ( 1 9 6 7 ) .  District  and Water Conservation  Engineering.  of the Economic Benefits of the Vernon Canada. Department of A g r i c u l t u r e ,  Annual Report.  Vernon, B.C., 1 9 2 0 to 1 9 7 0 .  18.  , and C. H. Brownlee. Scheduling of Irrigations in Orchards. Summerland I r r i g a t i o n Technical B u l l e t i n No. 5, Summerland, 1 9 6 9 .  19.  . Some Estimates of Irrigation Requirements in 1967. Canada Land Inventory Evaporation Stations, Summerland, 1 9 6 9 .  20.  . "Credit to Give f o r Rain When Scheduling I r r i g a t i o n i n Semi-Humid Areas," Canadian Agricultural Engineering^ V o l . 1 2 , No. 2, pp. 33-38.  21.  and H. C. Korven. "Effects of Weather Fluctuations on the Scheduling of I r r i g a t i o n , " Canadian Journal of Plant Science  3  Vol. 44 ( 1 9 6 4 ) .  22.  Willcocks, T. J . " I r r i g a t i o n Requirements f o r A l f a l f a i n the Nicola V a l l e y , " Unpublished Master's D i s s e r t a t i o n , University of B.C., 1970.  23.  Zimmerman, J . D.  24.  Personal interview with T. J . Willcocks, Canada Department of F i s h e r i e s .  Irrigation.  New York:  John Wiley & Sons, 1 9 6 6 .  59  GLOSSARY  A p p l i c a t i o n E f f i c i e n c y - The r a t i o of net volume of d e s i r e d a p p l i c a t i o n to the gross volume of water d e l i v e r e d by the s p r i n k l e r s to e f f e c t the desired a p p l i c a t i o n . A p p l i c a t i o n Rate - The rate a t which i r r i g a t i o n water i s applied to the s o i l .  Units: inches per hour.  E f f e c t i v e Rooting Depth - That depth i n the s o i l above which the roots obtain 90% or more of t h e i r water between i r r i g a t i o n s . Evapotranspiration  - Mater transpired by plants, b u i l t i n t o plant  t i s s u e , and evaporated from the s o i l surface.  Also c a l l e d  "Consumptive Use", Evapotranspiration Rate - Rate of evapotranspiration expressed i n inches per day, per i r r i g a t i o n i n t e r v a l , per month or per growing season. F i e l d Capacity  - S o i l water content retained by the s o i l following an  i r r i g a t i o n or heavy r a i n , a f t e r downward movement of water has materially decreased. I t i s the upper l i m i t of s o i l water a v a i l a b l e f o r plant use.  Units: percentage of dry weight of  s o i l , inches of water per f o o t of s o i l or per p r o f i l e . I n f i l t r a t i o n - The downward movement of free water i n t o the s o i l through the s o i l  surface.  I n f i l t r a t i o n Rate - The rate of downward movement of f r e e water i n t o the s o i l through the s o i l surface.  Units: inches per hour.  I r r i g a t i o n Cycle - The number of days to i r r i g a t e a given area not counting  the time l o s t during or between i r r i g a t i o n s .  I r r i g a t i o n I n t e r v a l - The number o f days between t h e s t a r t o f a n i r r i g a t i o n a t a n y one s p o t and t h e s t a r t o f t h e n e x t i r r i g a t i o n a t t h e same s p o t . L e a c h i n g - The p r o c e s s o f r e m o v i n g s o l u b l e m a t e r i a l f r o m t h e s o i l by passage o f w a t e r t h r o u g h t h e s o i l . Maximum A l l o w a b l e  S o i l Water D e f i c i t - The range o f w a t e r  content  between f i e l d c a p a c i t y and t h a t w a t e r c o n t e n t below w h i c h g r o w t h and y i e l d a r e a f f e c t e d a d v e r s e l y . Peak E v a p o t r a n s p i r a t i o n - The a v e r a g e d a i l y e v a p o t r a n s p i r a t i o n  during  the p e r i o d o f maximum e v a p o t r a n s p i r a t i o n , f o r a p e r i o d o f a n y stated length.  U n i t s : inches per day.  Permanent W i l t i n g P o i n t - The w a t e r c o n t e n t  o f t h e s o i l when p l a n t s  g r o w i n g i n i t a r e w i l t e d t o t h e p o i n t where t h e y w i l l n o t r e c o v e r when p l a c e d i n t h e d a r k f o r 12 h o u r s i n an atmosphere of 100% r e l a t i v e humidity.  I t o c c u r s a t a b o u t 15 atmospheres  o r 15 b a r s o f s o i l m o i s t u r e t e n s i o n . weight o f s o i l .  Also called  U n i t s : percentage o f d r y  "Permanent W i l t i n g P e r c e n t a g e " ,  S a f e I n t e r v a l - The maximum i n t e r v a l i n d a y s t h a t c a n be a l l o w e d between i r r i g a t i o n s i n t h e heat o f t h e summer w i t h o u t  danger  of i m p a i r i n g p l a n t growth o r y i e l d . Scheduling  o f I r r i g a t i o n - A p r o c e d u r e whereby w a t e r i s a p p l i e d i n s u c h  a manner t h a t t h e s o i l w a t e r c o n t e n t  i s maintained  w i t h i n the  optimum r a n g e , w i t h o u t u n n e c e s s a r y wastage o f w a t e r . S e a s o n a l E v a p o t r a n s p i r a t i o n - The t o t a l e v a p o t r a n s p i r a t i o n d u r i n g t h e g r o w i n g season o f t h e c r o p .  U n i t s : inches o f water .  S o i l Water D e f i c i t - F i e l d c a p a c i t y minus a c t u a l s o i l w a t e r  content.  U n i t s ; inches per f o o t of s o i l or per p r o f i l e . Transpiration - Evaporation  of water from the surface o f the p l a n t ,  and i n p a r t i c u l a r from the leaves.  I t does not include  evaporation of water adhering to the outside of leaves because of r a i n f a l l , i r r i g a t i o n or dew.  

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