IRRIGATION in the 21St Century Volume 1: Summary Report SOUTH SASKATCHEWAN RIVER BASIN IRRIGATION in the 21ST CENTURY INDEX to VOLUMES

SOUTH SASKATCHEWAN RIVER BASIN IRRIGATION in the 21st Century Volume 1: Summary Report SOUTH SASKATCHEWAN RIVER BASIN IRRIGATION IN THE 21ST CENTURY INDEX TO VOLUMES

Volume 1: Summary Report

Volume 2: On-Farm Irrigation Water Demand

I. Potential Evapotranspiration in Southern Alberta from Historical Weather Data II. Current Irrigation Management Practices, 1996 - 2000

Volume 3: Conveyance Water Management

I. Seepage Losses from Irrigation Canals in Southern Alberta II. Evaporation Losses from Irrigation Canals and Reservoirs in Southern Alberta III. Return Flow from Alberta's Irrigation Districts

Volume 4: Modelling Irrigation Water Management

I. Deriving Irrigation Water Demands Through the Irrigation District Model (IDM) II. Determining Water Supply Availability to Meet Irrigation Demands

Volume 5: Economic Opportunities and Impacts

I. Assessing the Farm Financial Risks and Impacts of Irrigation Water Supply Deficits II. The Economic Benefit of Growth in Alberta Irrigation Development SouthSaskatchewan River Basin Irrigation in the 21stCentury

Copies of this report are available from the Alberta Irrigation Projects Association 909, 400 - 4 Avenue South Lethbridge, Alberta T1J 4E1 (403) 328-3068 and the Irrigation Branch, Alberta Agriculture, Food and Rural Development Agriculture Centre 100, 5401 - 1 Avenue South Lethbridge, Alberta T1J 4V6 (403) 381-5140

Citation: Irrigation Water Management Study Committee. 2002. South Saskatchewan River Basin: Irrigation in the 21st Century. Volume 1: Summary Report. Alberta Irrigation Projects Association. Lethbridge, Alberta.

Reproduction of up to 100 copies by non-profit organizations, or photocopying of single copies, is permitted. Please acknowledge the Alberta Irrigation Projects Association. All other reproduction, including storage in electronic data retrieval systems, requires written permission from the Alberta Irrigation Projects Association.

Photographs on pages 10 and 11 are courtesy of The Galt Museum, Glenbow Archives, and Eastern Irrigation District. All other photographs are courtesy of Alberta Agriculture, Food and Rural Development. Acknowledgments

The databases and analytical tools contained in this report will be of value to the irrigation industry, water managers and the public. This summary report draws heavily on the technical reports contained in Volumes 2 to 5. A large measure of the credit for this report goes to the staff of the Irrigation Districts and the Irrigation Branch of Alberta Agriculture, Food and Rural Development (AAFRD). Field staff persevered through bad weather, equipment failures and calibration challenges to gather the raw data that made this report possible. Other staff analyzed the mountain of collected data and ensured the results were accurate and understandable. A share of the credit must also go to the many farm producers who willingly participated in the research and monitoring studies. The report was written primarily by J. R. (Dick) Hart, Hart Water Management Consulting, Calgary, Alberta. Barbara Grinder, Viewpoints Communications, Hill Spring, Alberta, completed the final edit and formatted the report. The report was printed by Dial Printing Inc. in Edmonton, Alberta. Irrigation demand modelling and data assimilation software were developed under contract by Phoenix Engineering Inc., Calgary, Alberta. Development of the economic risk and impact analysis software was carried out through the Economics Unit of AAFRD. The report was reviewed by the Irrigation Water Management Study Steering Committee and board members and staff of the irrigation districts. Their collective input is much appreciated.

i Contents Executive Summary ...... xi

Chapter I. Introduction A. Purpose and Rationale ...... 3 B. Approach ...... 4 C. About the Summary Report ...... 5

Chapter II. Irrigation Development A. History of Irrigation in Southern Alberta ...... 9 1. The Early Years: Pre-1920 ...... 9 2. The Adjustment Years: 1920 to 1950 ...... 13 3. Rehabilitation and Expansion of the Delivery Systems: 1950 to 1970 .. 16 4. Provincial and Irrigation District Control: 1970 to Present ...... 17 B. South Saskatchewan River Basin Water Management Policy ...... 20 C. Irrigation Expansion Guidelines ...... 21 D. AENV's SSRB Water Management Planning Process ...... 24

Chapter III. Scope and Methodology A. Objectives ...... 27 B. Organizational Structure and Funding ...... 28 C. Components of the Irrigation Water Management Study ...... 30 1. On-farm Working Group ...... 30 2. Distribution Working Group ...... 34 3. Modelling Working Group ...... 37 D. Simulation Modelling ...... 40 E. Limitations of the Irrigation Water Management Study ...... 42 1. Private Irrigation ...... 42 2. Non-irrigation Uses in the South Saskatchewan River Basin ...... 44 3. Non-irrigation Uses through the Works of the Irrigation Districts ...... 44 4. Water Management Headworks Losses ...... 45 5. Climate Variability ...... 45

Chapter IV. Key Research Findings A. On-Farm Component ...... 50 1. Agro-climatic Database ...... 50 2. Crop Types and Water Requirements ...... 51 3. On-farm Irrigation Systems and Application Effficiencies ...... 61 4. Irrigation Management Practices ...... 64 B. Irrigation District Distribution System ...... 67 1. District Characteristics ...... 68 2. Canal Seepage ...... 72 3. Evaporation ...... 74 4. Return Flow ...... 77 C. Water Demand Summary Based on Key Findings ...... 83 D. Conclusions ...... 85

Chapter V. Simulation Modelling A. Introduction ...... 89 B. Modelling Assumptions and Calibration ...... 90 1. Irrigation District Model (IDM) ...... 90 2. Water Resources Management Model (WRMM) ...... 91 3. Farm Financial Impact and Risk Model (FFIRM) ...... 92 C. The Scenarios ...... 98 D. Conclusions ...... 103

iii Chapter VI. Potential for Irrigation Expansion A. Analysis of IDM Irrigation Demand Data ...... 107 1. Comparisons with 1991Regulation Licence Volumes ...... 108 2. Basin Specific Variations ...... 109 3. District Specific Variations ...... 110 4. Variation in Water Use Efficiencies ...... 110 5. Impacts of Water Management on Gross Diversion Demand ...... 111 B. Analysis of WRMM Water Deficit Data ...... 112 C. Analysis of FFIRM Output on Impacts of Irrigation Deficits ...... 114 D. Detailed Assessment of Selected Expansion Scenarios ...... 116 E. Conclusions ...... 134

Chapter VII. Benefits of Irrigation Development A. Introduction ...... 139 B. 1999 Benefits of Irrigation Development ...... 140 1. Primary Agricultural Production ...... 140 2. Farm Supply Implications ...... 141 3. Agri-processing Implications ...... 141 4. Total Agricultural Impacts ...... 142 5. Non-agricultural Benefits of Irrigation Infrastructure ...... 142 C. Opportunities for the Future ...... 143 1. Livestock ...... 143 2. Agri-processing ...... 144 3. Impacts of Intensification and Expansion of Irrigation ...... 144 D. Conclusions ...... 146

References ...... 151

Appendix ...... 155

List of Acronyms ...... 175

Unit Conversion Chart

iv Executive Summary Executive Summary

A. INTRODUCTION Irrigation in Alberta has an interesting and colourful history that spans more than a century. The industry has experienced periods of great optimism, bitter disappointment, struggling for survival, maturation, and triumph. The irrigation districts are now well established and operate as progressive enterprises. A variety of water uses have been integrated into their developments and operations, including wildlife conservation, recreation, hydro power and water supplies to communities, industries, livestock and domestic users. Crop diversity and value-added commercial enterprises are encouraged and are increasing within the districts. Irrigation has become an integral component of the social and economic fabric of southern Alberta. The irrigated area in southern Alberta has been steadily increasing. While expansion is important to the health of the industry and the economy of the province as a whole, it is recognized that irrigation places a high demand on the limited water resources of the region. In 1991, the Alberta government established irrigation expansion guidelines that limit the amount of water that can be allocated to the irrigation districts and to private irrigation projects in the South Saskatchewan River Basin (SSRB). The guidelines are incorporated in the 1991 South Saskatchewan Basin Water Allocation Regulation under the Water Act. In establishing theRegulation , the government recognized that existing scientific information on water use was inadequate to make definitive decisions on irrigation expansion and called for theRegulation to be reviewed and refined in the next decade.

N RED DEER

IVER R

DEER RED DEER RIVER BASIN D E R

R O Drumheller SE B U RED D

RIVER D CREEK Saskatchewan British Columbia E E R R IV E BERRY 12 R

RIVER Strathmore

ELBOWCALGARY R BOW RIVER 13 E BOW RIVER BASIN RIV Brooks ER OD RIV AN O W H L IG IT H T L TCHEW Irrigation Districts E

W SASKA RIVER 11 1 Mountain View (MVID) WILLOW TH MEDICINE Leavitt (LID) SOU HAT 2 OLDMAN OLDMAN RIVER Vauxhall C R 9 3 Aetna (AID) E BASIN 10 E K Picture MANRIV RIV Butte OLD ER 4 United(UID) ER Bow Island 5 Magrath (MID) 7 9 8 Taber 9 Coaldale CRO 6 Raymond (RID) WSN . LETHBRIDGE SOUTH SASKATCHEWAN EST R RIVER SUB-BASIN 7 Lethbridge Northern (LNID) R. E 6 L 8 Taber (TID) T RIVER RIVER S A Y 5 9 C 4 R. St.Mary River (SMRID) BELL Y R 10 Ross Creek (RCID) 2 A M MILK RIVER WATERTON

11 Bow River (BRID) 1 3 ST. 12 Western (WID) Montana 13 Eastern (EID)

xi B. OBJECTIVES Irrigation districts and producers recognize the need to be pro-active on water conservation and environmental matters. To address the additional demands irrigation expansion places on water resources and the environment, a study of irrigation district water requirements and opportunities was initiated in 1996 using the best available science, technology, long range planning, and local knowledge. The study was a cooperative effort of the Alberta Irrigation Projects Association (AIPA), representing the 13 irrigation districts in Alberta, the Irrigation Branch of Alberta Agriculture, Food and Rural Development (AAFRD), and the Prairie Farm Rehabilitation Administration (PFRA) of Agriculture and Agri-Food Canada (AAFC). Alberta Environment (AENV) acted as a resource and liaison. As part of the study's mission to provide a comprehensive, scientifically sound analysis of current and future water management within the irrigation districts, six specific objectives were set. ! Identify and quantify current irrigation water requirements and the state of current irrigation water management. ! Quantify changes in water use and water management efficiencies during the 1990s. ! Quantify possible future irrigation water use. ! Develop leading-edge computer tools to assess current and future irrigation water use and management opportunities. ! Assess the risks, impacts and possibilities of irrigation area expansion. ! Assess the potential contribution of irrigation expansion to the provincial economy.

C. KEY ACTIVITIES AND FINDINGS The Irrigation Water Management Study involved more than four years of field research, data collection and analysis, and focused on five component areas: ! On-farm water use; ! Distribution system characteristics; ! Irrigation district computer model development; ! Impacts of irrigation water shortages; and ! Analyses of current and future irrigation scenarios. Work was carried out by staff from the irrigation districts, AAFRD, AENV, and by consultants. Funding for instrumentation and consultants' work was cost- shared by AAFRD, PFRA, and by the irrigation districts through their umbrella organization, the AIPA. The following key activities were undertaken by the project teams. ! Agro-climate - A comprehensive, historical agro-climatic database, that included the SSRB, was used to determine associated potential evapotranspiration data in the basin. This database, expanded from one originally developed by AAFC and Environment Canada, is referenced to a 50 km to 50 km grid. The expanded database was the source of all climate data required in the computer modelling of crop specific water demands, soil moisture balances and evaporation losses. The database was also used to assess the impacts of water shortages on crop yields and to assist in the assignment of on-farm irrigation system flow capacities based on regional climatic conditions.

xii ! Cropping Patterns - A review of historical cropping patterns within the irrigated areas and a report on the prospects for the future of the agricultural industry were completed. Based on this work, it is projected the crop mix for irrigated agriculture will evolve toward an increased area of forage to support the livestock industry, an increased area of specialty crops to support value-added processing, and a reduced area of cereal grains. This will result in slightly higher water requirements than the current crop mix. ! Irrigation Water Management - The 1991Regulation was based on meeting 100% of crop water requirements. A comprehensive, five-year (1996 to 2000) monitoring program determined that the amount of water irrigation farmers were applying meets, on average, about 84% of the crop water requirement to obtain optimum yields. However, water application has increased during the past 10 years, and will likely continue to increase to about 90%. Assuming continued improvements in on-farm and irrigation district infrastructure and water management, overall irrigation water management efficiencies could improve in the Oldman Basin districts from the 1999 level of 53% to 64% in the future. Similarly, efficiencies are projected to increase from 40% to 55% for the Bow Basin districts. ! Irrigation Water Demand - A water demand analysis for the 13 irrigation districts was conducted using a methodology and format similar to that used in 1991, using updated and more scientifically sound data. The total demand for the 1991Regulation limit of 531,434 hectares is estimated to be 2,920,714 cubic decametres, compared with theRegulation licence volume of 3,622,792 cubic decametres identified in 1991. This represents a reduction of about 19%. As can be seen in the figure below, the water licence allocations defined in the 1991Regulation are greater than the demands derived through modelling of both the 1999 level of development and the projections for a 10% expansion beyond theRegulation limits. The figure also illustrates Return flow the extent of relative changes in the individual irrigation water demand Infrastructure losses components resulting from ongoing water use Farm losses efficiency improvements, as modelled in comparison 4 Crop irrigation requirement to the 1991Regulation allocations. The overall water demand is noticeably lower in 1999 and with 10% expansion beyond theRegulation limit, even as 3 projected irrigation management moves closer to meeting near-optimum crop water requirements in the expansion scenario. 2 ! Water Losses - The three principal causes of

3 consumptive water loss in an irrigation project are

described below. (dam in millions) 1 On-farm Application: The percentage of water diverted to on-farm systems that actually ends up

being available for crop use is referred to as the Irrigation Demand (9 years out of 10) on-farm application efficiency. This overall value 0 had increased from approximately 60% in 1990 Regulation Limit 1999 Conditions Regulation Limit to about 71% by 1999. Additional efficiency 530,948 ha 490,401 ha + 10% Expansion gains are projected for the future as application 588,940 ha Comparison of modelled irrigation demand volumes technologies continue to advance and are and theRegulation allocation (excluding Ross Creek adopted. Overall application efficiencies could Irrigation District). approach 78%.

xiii Canal Seepage: The study of actual seepage losses from canals in southern Alberta indicated the volume of seepage from canals is about 2.5% of the licence volume, much lower than the 13% estimated in 1991 when the irrigationRegulation was established. Evaporation: Canal and reservoir evaporation losses from the current district infrastructure are about the same as estimated in 1991. Though some decrease in evaporation losses will occur through further installation of pipelines, canal evaporation will not change significantly. Reservoir evaporation losses will increase if new offstream reservoirs are developed within the districts. ! Return Flow - Many of the irrigation districts installed automated monitoring equipment to accurately measure the flow of water that returns to the river from the districts. Monitoring showed return flow varied substantially from district to district, from a low of 7% to a high of 56% of the gross diversion. In five of the six largest districts, average return flow was substantially higher than assumed in the 1991Regulation. The exception is the St. Mary River Irrigation District, which returns less water than was assumed in 1991. ! Potential Expansion - Ten scenarios, representing current and possible future conditions within the irrigation districts, were computer simulated (modelled) to determine the impact of various management measures on gross irrigation demand. The analysis indicates that various one-at-a-time management shifts affect the gross diversion demand as shown in the table below. Values represent changes resulting exclusively from the expansion variable. Variables shown can be applied in combination with any of the other management variables. The percentage change in gross demand is referenced to the Base Case. For example, increasing the percentage of specialty crops in the overall crop mix could result in an increase in water use of more than 3%. Moving to more efficient sprinkler systems could result in a decrease in gross diversion demand of almost 6%. The extent of the impacts will vary from district to district. Seven of the scenarios were modelled to determine the possible financial impacts of irrigation deficits on farm enterprises. The model revealed that

Impacts of management decisions on gross irrigation demand. Irrigation Expansion Change Management Area from in Gross Variable (ha) Base Case Demand (%) (%) Base Case - 1999 conditions 490,385 Expansion to 1991Regulation limit 535,400 9.2 5.4 Expansion to 1991Regulation plus 10% 588,939 20.1 13.4 Expansion to 1991Regulation plus 20 % 642,479 31.0 20.0 Crop Mix Shift(increasing % of forage and specialty crops) 3.1 System Mix Shift(increasing % of higher efficiency sprinkler systems) -5.7 On-farm System Management Efficiency Improvements -3.0 Increase toward On-farm Crop Water Optimization 9.5 Improvements in District Return Flow Management -3.3

xiv even if water supply deficits occur in increasing magnitude, frequency and duration as a result of irrigation expansion, the economic sustainability for farm enterprises may still be maintained through improvements in water use efficiency and increases in on-farm water applications. This is particularly significant for those farm enterprises that can transfer water from low value crops to higher value crops during water deficit years. Farm economic sustainability is sensitive to the type and diversity of crop mix within an enterprise. For instance, model results indicate that, for some regions, farm enterprises wholly dependent on grains and oilseed production may not be sustainable in the future, particularly if water supply deficits increase and water applications remain at current levels. However, diversification to higher value specialty crops and forages can provide higher net revenues, even with more frequent and higher water supply deficits that arise from irrigation expansion.

D. BENEFITS OF IRRIGATION DEVELOPMENT 1. Current Benefits Irrigation has had a profound impact on southern Alberta and the entire province. Currently, irrigation development occupies 4% of the cultivated land in southern Alberta's irrigation districts. Considering the increases in primary production due to irrigation and the spin-offs in agri-food processing, this level of irrigation contributes about $832 million or 18.4% to the agri-food gross domestic product for Alberta. In addition, the irrigation infrastructure provides significant non-irrigation benefits related to municipal and industrial water supplies, recreation, tourism, and wildlife. Irrigation development reduces farm risks, fosters on-farm diversity, increases profit margins, and reduces the need for government and private safety nets. Irrigation improves the long-term sustainability of smaller farm units. The larger requirement for irrigation supplies and services supports rural agri-business enterprises. Higher labour requirements for primary production on irrigated land, for the agricultural service sector, and for irrigation induced post-primary processing, increase rural population and contribute to more vibrant communities and infrastructure development.

2. Future Opportunities Irrigation intensification and expansion will contribute to the province's agri- food strategy and to general social and economic objectives in Alberta. For example, the agricultural development strategy in Alberta calls for increased livestock production and strong growth in the agri-processing sector. To be successful in meeting growth targets, a significant amount of growth must take place in the irrigation-dependent southern part of the province. This region has high potential for increased forage production and currently has a high value- added processing to primary production ratio. Many of the crops that are in demand as processed products must be grown under irrigation in southern Alberta, where the longer growing season, high heat units, and relatively secure water supply provide suitable and stable conditions. Results of the Irrigation Water Management Study provide a status report on the irrigation industry in Alberta and on prospects for the future. With the databases and analytical tools that have been developed by government agencies and the irrigation districts working together, the districts and government are well-positioned to address the challenges facing the industry in the 21st century.

xv E. CONCLUSIONS Based on the technical information that has been developed, and the simulation modelling conducted in the Irrigation Water Management Study, the following key conclusions are drawn.

Simulation modelling indicates that overall irrigation efficiencies could improve from the current 54% to 64% for the Oldman River Basin districts, and from the current 40% to 55% for the Bow River Basin districts, with continued improvement in on-farm systems, district infrastructure, and water management. On-farm efficiencies have improved from about 60% in 1990 to about 71% in 1999 due to the shift to more efficient irrigation systems and methods, and improved on-farm management. District losses and return flows have decreased due to rehabilitation of district infrastructure, replacement of canal laterals with pipelines, automation of structures, extensive monitoring, and improved district water management.

A 10% to 20% expansion in the irrigated area beyond the 1991 Regulation is sustainable in the Bow Basin, with improvements in water use efficiency, reduced return flows, and higher crop water applications. All financial performance indicators showed improvements compared to current conditions in the Bow Basin, in spite of higher irrigation deficits. This conclusion does not apply equally to all districts nor to all irrigation blocks within the districts. More detailed analyses are required to examine impacts of expansion on individual districts and blocks.

Up to a 10% expansion in the irrigated area beyond the 1991 Regulation could be considered in the Oldman Basin, with efficiency improvements, reduced return flows, and higher crop water applications. A cautious approach to irrigation expansion in the Oldman Basin is recommended. Though water supply deficits would be significantly higher in this basin than in the Bow River Basin, most financial performance indicators show improvements from the current situation. However, some irrigation blocks and districts should probably not expand beyond the 1991 Regulation. Irrigation districts will require more detailed analyses before making the decision to expand.

Financial modelling indicates that irrigated farm financial performance can be improved from current conditions, even with irrigation expansion and more frequent and higher water supply deficits.

Comparing model output for expansion scenarios against 1999 conditions indicated that average net farm incomes increased, and the risk of insolvency decreased, for most representative farms. The probability of negative net farm income in any one year decreased for all farms in the Bow Basin districts, but increased for some farms in the Oldman Basin, indicating higher variability in annual income in the Oldman Basin.

xvi Prerequisites to improved farm financial performance are on-farm and district water use efficiency improvements, reduced return flows, higher crop water applications, and crop mixes that include at least one high value crop. Improved efficiencies and reduced return flows will minimize the magnitude and frequency of water supply deficits. Higher crop water applications will increase yields and revenues in non-deficit years, so that producers are in a better position to withstand lower revenues in deficit years. Farms that irrigate only cereals and oilseeds are considerably less profitable than farms that include higher value specialty crops or forages. Including a higher value crop in the mix provides the opportunity to maximize revenues by shifting water applications from low value crops to higher value crops.

Irrigation water supply deficits less than 100 mm per year are not considered to have serious financial consequences for most producers. At the crop level, the net effect of a specified water supply deficit is only a portion of that deficit. The actual net effect at the crop level is somewhat reduced because a portion of the projected deficit consists of losses incurred through water application inefficiencies that were already accounted for in the irrigation demand. These on-farm losses do not actually occur if water is not available for diversion to meet the projected irrigation demand. For example, a projected 100 mm deficit in the gross diversion supply may only translate into a 70 mm to 75 mm deficit at the crop level. Also, irrigators can redistribute available water to those crops that generate higher net revenues. As a result, the impact of smaller projected gross diversion deficits (less than 100 mm) is unlikely to have much financial significance.

Irrigation intensification and expansion will make a positive contribution to Alberta's agri-food industry and the province’s social and economic objectives. The agricultural development strategy in Alberta calls for increased livestock production and strong growth in the agri-processing sector. To be successful in meeting growth opportunities, significant growth must take place in the irrigation-dependent southern part of the province. This region has high potential for increased forage production and currently has a high value-added processing to primary production ratio. Irrigation contributes to the province's agricultural resource base by increasing the productivity of the land by 250% to 300% compared with dryland areas. Many of the crops that are in demand as processed products must be grown under irrigation in southern Alberta, where the longer growing season, high heat units, and relatively secure moisture conditions provide stable, high quality production. Irrigation improves the sustainability of the family farm, supports agri- business enterprises, and contributes to infrastructure development and more vibrant communities. Irrigation infrastructure provides significant non- irrigation benefits related to municipal and industrial water supplies, recreation and tourism, and wildlife conservation.

xvii Innovation, research, and improved technology will continue to be critical components of agricultural growth, and will add to long-term success in primary production and value-added processing. Innovation and research have brought new ideas, new resources, and greater potential for economic synergies to the agricultural industry, including the establishment or expansion of several multi-national agri-processors in the irrigated south. Potential for similar growth in the future is excellent.

Ongoing research and integrated planning are required by the irrigation districts and government agencies to further improve irrigation water use efficiency, increase value-added production, and ensure that Alberta's water resources are used wisely. The Irrigation Water Management Study has provided the most comprehensive and integrated assessment of past, present and future irrigation water management in Alberta's history. The study will help irrigation districts and government make informed decisions about sustainable development and water allocations in the South Saskatchewan River Basin. Continued evaluation of future irrigation and water management opportunities is needed to support Alberta's economic, social and environmental objectives.

xviii 1.

Chapter Introduction Chapter I. Introduction

A. PURPOSE AND RATIONALE Irrigation has become an integral component of the social and economic fabric of southern Alberta. The benefits of irrigation go well beyond the direct impacts of diversifying, stabilizing and increasing agricultural productivity at the farm level. Irrigation benefits extend to the suppliers of supporting goods and services; to Alberta's rapidly growing agri-processing industry; and to the domestic, municipal, industrial and recreational water users, and wildlife conservationists who rely on irrigation infrastructure for their water supplies. The irrigated area in southern Alberta has been steadily increasing. Expansion is important to the health of the irrigation industry, however, irrigation places a high demand on the limited water resources of southern Alberta. Irrigation water users recognize they must be pro-active on water conservation and environmental matters. The additional demands that irrigation expansion places on the water resources and the environment must be addressed, with the objective of preserving these assets for future Albertans. Water management decisions should be based on the best practical science and technology, long range planning, and local knowledge. In May 1990, the province announced the need to limit the amount of water to be allocated for irrigation purposes in the South Saskatchewan River Basin (SSRB). In September 1991, guidelines were established under the South Saskatchewan Basin Water Allocation Regulation which considered the water supplies available and the needs of irrigation and all other consumptive and instream uses (Alberta Environment 1991). Recognizing the limitations of the data and the uncertainties related to water requirements for various purposes when the 1991Regulation guidelines were established, the province committed to a review in 2000. A study of irrigation district water requirements and opportunities was initiated in 1996 as a cooperative effort of the Alberta Irrigation Projects Association (AIPA), representing the 13 irrigation districts in Alberta, the Irrigation Branch of Alberta Agriculture, Food and Rural Development (AAFRD), and the Prairie Farm Rehabilitation Administration (PFRA) of Agriculture and Agri-Food Canada. The Irrigation Water Management Study was carried out to provide a comprehensive, scientifically sound analysis of current and future water management within the irrigation districts. There were six objectives of the study. ! Identify and quantify current irrigation water requirements and the state of current irrigation water management. ! Quantify changes in water use and water management efficiencies during the 1990s. ! Quantify possible future irrigation water use. ! Assess the risks, impacts and possibilities of irrigation area expansion. ! Develop leading-edge computer tools to assess current and future irrigation water use and management opportunities. ! Assess the potential contribution of irrigation expansion to the provincial economy. The results of this study provide a statement on the state of the irrigation industry in Alberta, and on prospects for the future. The information will be used in the province’s SSRB water management planning process under the Water Act.

3 B. APPROACH The Irrigation Water Management Study involved more than four years of field research, data collection, organization and analysis, focusing on five component study areas: ! On-farm water use; ! Distribution system characteristics; ! Irrigation demand model development; ! Impacts of irrigation water shortages; and ! Analysis of current and future irrigation scenarios. The study focused on water requirements and management in the 13 irrigation districts (Figure 1). Water requirements for uses other than district irrigation, such as domestic, municipal, industrial, private irrigation, recreational and instream uses, were not specifically addressed in this project. However, in the analysis of current and future scenarios, the most recent AENV projections of the requirements for these other uses were included.

N RED DEER

RIVER

DEER RED DEER RIVER BASIN D E R

ROSEBUD Drumheller RED

British Columbia RIVER DEER CREEK Saskatchewan Y

R IV E BERR 12 R

RIVER Strathmore

ELBOWCALGARY BOW RIVER 13 BOW RIVER BASIN RIVER Brooks

D A O RIVER O W

W E H LITTLE IG H TCH

BOW SK

SA RIVER 11 WILLOW MEDICINE SOUTH HAT OLDM OLDMAN RIVER Vauxhall CREEK AN BASIN 9 10 Picture MANRIV RIVER Butte OLD ER Bow Island Irrigation Districts 1999 Assessed Area 7 9 8 Taber 9 Coaldale (ha) CROW SOUTH SASKATCHEWAN SNEST R. LETHBRIDGE 1 Mountain View (MVID) ...... 1,506 RIVER SUB-BASIN R. R 2 Leavitt (LID)...... 1,930 E 6 IV RIVER R 3 Aetna (AID) ...... 1,461 Y 5 CASTLE N 4 R. United(UID) ...... O BELL 4 13,902 Y 5 Magrath (MID) ...... 7,406 2 AR M M ILK RIVER 6 Raymond (RID) ...... 18,515 WATERT 1 3 ST. 7 Lethbridge Northern (LNID) ...... 62,680 8 Taber (TID) ...... 33,178 Montana 9 St.Mary River (SMRID)...... 148,585 10 Ross Creek (RCID)...... 490 11 Bow River (BRID) ...... 85,450 12 Western (WID) ...... 35,665 13 Eastern (EID) ...... 113,760 Total Assessed = 524,528

Figure 1. Irrigation districts within the South Saskatchewan River Basin of southern Alberta.

4 Work was carried out by staff of the irrigation districts, AAFRD, AENV and consultants. Funding for instrumentation and consultant studies was cost-shared by AAFRD, PFRA and the irrigation districts, through their umbrella organization, the AIPA. AENV is continuing to review and update requirements for non-irrigation uses. Although this project does not specifically address private irrigation, the information and databases developed are applicable to private irrigation projects. Information on crop mixes, agro-climatic conditions and water requirements is being used for water management planning within private irrigation blocks.

C. ABOUT THE SUMMARY REPORT The 5-volume report,Irrigation in the 21st Century , consists of this Summary Report (Volume 1), and four technical volumes. This volume reviews the irrigation district water requirements and the results of the Irrigation Water Management Study. It has been prepared to serve three purposes. ! To promote a better public understanding of the current state of the irrigation industry in Alberta, the role it plays in the province's economy, and the ways irrigation can continue to contribute to economic growth and an improved quality of life. ! To provide input to the province's SSRB water management study being led by AENV, and to future basin planning activities under the Water Act. ! To provide current databases and analytical tools for the individual irrigation districts to use in operations and planning, including the need to assess opportunities for growth within their respective districts. Chapter II of this report provides background information on the development of the irrigation industry in Alberta, and the events and circumstances leading to this study. Chapter III describes the objectives and scope of the overall study and its components and the methodology used. Chapter IV summarizes the findings of each component of the research program. The approach and assumptions used in simulation modelling, and the scenarios modelled, are discussed in Chapter V. The results of simulation modelling for various expansion and water management scenarios are presented in Chapter VI. Chapter VII discusses the benefits of irrigation development to the province. A list of the references cited in this report follows Chapter VII. This Summary Report draws heavily on technical reports on various components of the Irrigation Water Management Study. These reports were prepared by AAFRD staff and consultants, and are included in Volumes 2 to 5. The technical reports themselves include references that are not repeated in this Summary Report. Metric Conversions Appendix A of this Summary Report contains tables with results of the simulation modelling. Appendix B contains graphics on simulation modelling Length or depth 1 kilometre (km) = 0.621 miles that are supplemental to the body of the report. 1 millimetre (mm) = 0.0394 inches Abbreviations and acronyms used in this volume are shown in brackets following first use of the full name and may be repeated from time to time. Area Where names of government agencies have changed during the years, the current 1.0 hectare (ha) = 2.47 acres name has been used. For instance, the acronym AAFRD could refer to the former Volume department, Alberta Agriculture, or the current department, Alberta Agriculture, 1.0 cubic decametre (dam3 ) Food and Rural Development. A list of acronyms appears at the end of the = 0.81 acre feet volume. Rate of flow SI units (metric) are used throughout the report. Some readers may be more 3 familiar with imperial units. Conversions of the most commonly used units are 1.0 cubic metre per second (m /s) = 35.315 cubic feet per second shown here. A table of conversion factors for all units used in this report is provided on the inside back cover. The significant digits are carried to avoid round-off error in the myriad of computations that were carried out.

5 II.

Chapter Irrigation Development Chapter II. Irrigation Development

Irrigation in southern Alberta has a 100-year history. The historical circumstances that set a pattern for the development of most of the irrigated area in Alberta provides a perspective on the land bases, design and layout of infrastructure, and the water licences that have been inherited by current districts. These factors continue to play a significant role in the management of today's districts. More recently, the province has taken steps to address water supply concerns and environmental issues, as water development in the South Saskatchewan River Basin approaches the limits of its water supply. These circumstances and events, described below, provide background and context for the Irrigation Water Management Study.

A. HISTORY OF IRRIGATION IN SOUTHERN ALBERTA The development and management of irrigation districts in Alberta have evolved during the past 100 years through an interesting series of events and circumstances, some of which are noted on the overleaf and in Figure 2. Each of the 13 existing districts has its own unique history, often involving a community- minded champion with desire and dogged determination to better the economic and social standing of his own family and his neighbours. An account on the formation of each individual district is beyond the scope of this report. However, a review of the history of the districts reveals a pattern of four distinct phases that apply to most irrigation districts and to the industry as a whole. These four phases are discussed in turn below.

1. The Early Years: Pre-1920 The early years of irrigation in Alberta were characterized by admirable foresight, optimism, enthusiasm and speculation. William Pearce, a Department of the Interior federal government official in the late 1800s, has been credited with playing a major role in formulating policies on resource development in western Canada. Pearce, an enthusiastic promoter of irrigation, saw irrigated agriculture as a key to stimulating settlement on the drought-prone Canadian prairies. Recognizing that the water law of the day, British common-law riparian rights, was a deterrent to large-scale irrigation, he and Col. J. S. Dennis, the Interior Department's Chief Inspector of Surveys, were largely responsible for developing the Northwest Irrigation Act of 1894. The Act suppressed individual riparian rights and vested in the Crown the right to control the diversion and use of water through a licensing system, in a manner they believed would encourage investment in irrigation infrastructure, protect individual and corporate water users, and result in the greatest public good (Dennis 1894). Government policy of the time was to conduct land and water surveys to determine, in a general way, the location and engineering feasibility of potential irrigation developments. Actual development was left to private enterprise. In the early years, there was a lack of information on the agro-climatic and agronomic parameters important to determining the feasibility of irrigation projects. Nevertheless, Department of the Interior officials identified and publicized numerous potential, large-scale projects. Some of these projects have not yet been developed, some were developed and have failed, and others were developed and have endured and prospered.

9 ACentury of Irrigation in Alberta 1890

19001900 Corporate enterprise

Excavation of St. Mary Project main canal 1900. - Optimism 19181918 - Enthusiasm

1920

19331933 Irrigation districts - Adjustments - Reform

William Pearce 1848-1930 1950 Father of Irrigation Federal government in Alberta involvement - Renewal - Stability - Expansion 19481948 1970

Provincial Control of Headworks - Rehabilitation - Growth

1990 Carl Anderson District Autonomy 1899 - 1998 - Environmental 19991999 Irrigation Visionary responsibility and Champion 2000

10 1891 April 16 - Magrath Gazette Irrigation scheme in southern Alberta rouses interest 1893 April 14 - Magrath Gazette Irrigation bill finally introduced in Parliament 1899 February 23 - Lethbridge News Incalculable benefits to accrue to southern Alberta irrigation says E.T. Galt in Medicine Hat 1912 May 8 - Lethbridge Daily Herald To make the prairie blossom - immense irrigation projects now in progress south of Lethbridge North side of Galt Gardens, 1903 1913 December 23 - Lethbridge Daily Herald Great possibilities ahead from irrigation system to be built in Taber area 1921 October5-Morning Albertan Gigantic plan to irrigate vast areas in Alberta - Wm. Pearce outlines plans for project in Hanna 1924 February 28 - Morning Albertan CPR contract farmers threaten - unless demands are granted 1924 March 4 - Calgary Herald Receiver appointed for Canada Land and Irrigation Company 1931 January 12 - Lethbridge Herald Intention of government to implement Wilson Commission recommendations 1931 August 6 - Calgary Albertan United Irrigation District farmers win relief - interest waived 1949 September 17 - Lethbridge Herald St. Mary - Milk Rivers Project assures bright future -Dominion government to pay costs of main reservoirs and canals connecting them 1957 September 17 - Medicine Hat News Province to spend $4,000,000 on West Block of Bow irrigation system 1980 August 30 - Calgary Herald A victory for irrigation - half billion dollar plan announced for irrigation improvements in southern Alberta 1989 June 10 - Lethbridge Herald LNID headworks system rehab wins government, farmer praise 1999 September 5 - Calgary Herald The water of life: Albertans clamour for larger stake in precious resource

Figure 2. Irrigation issues and events as reflected in the newspapers of the day.

11 Alberta's major irrigation systems were initially developed by corporate enterprises with the expectation they would increase productivity and land values enough to pay construction and annual operation and maintenance costs, as well as a return on the investment. Companies that had received large land grants in return for constructing railways had the additional objective of hastening the settlement of the Canadian prairies to increase commerce and rail traffic. Enthusiasm for irrigation was high. Department of the Interior administrators authorized construction of works for delivery of water to a number of corporate irrigation projects and committed large quantities of water for irrigation. In the Department's 1912 report on irrigation, F. H. Peters, Commissioner of Irrigation, stated that: "In Alberta the total amount of water granted for irrigation purposes is 23,114 cubic feet per second (655 m3 /s), or enough to irrigate 3,467,100 acres (1,403,088 ha) of land, according to the authorized duty of water which is 2.023 acre feet per acre (617 mm/ha)." (Peters 1912) Five large irrigation projects, all corporate enterprises, accounted for over 97% of this water grant, as shown in Table 1. The term water grant does not necessarily mean that a licence to use water was issued. Not all the works required to divert the quantities noted in Table 1 were constructed. In some cases, works of lower capacities were constructed and subsequently licensed to divert water. As a matter of policy, the Department of the Interior would not issue licences for diversions exceeding the capacities of the works constructed or the capacities required to serve the developed irrigation area. On some projects, a fiscally cautious, phased approach was taken, each phase initiating operations and generating revenue before proceeding with a subsequent phase. On other projects, construction proceeded on the delivery system and the entire major distribution works at once, in afast-track mode, in an effort to get the land “under the ditch” as quickly as possible and thereby increase its sale value. Some of the works so constructed were never used and have been abandoned; others are still not being used to the capacity for which construction was authorized. By 1919, close to 76,890 hectares were being irrigated within areas of the current Western, Eastern, St. Mary River, Magrath and Raymond Irrigation Districts. Works were either in place or soon to be completed to irrigate a substantially larger area. No water licences were issued for irrigation of lands within the current irrigation districts in the pre-1920 period. Diversions were made on several projects under other types of authority, such as a "Permit to use water prior to issue of a Licence" issued by the Department of the Interior.

Table 1. Large irrigation water grants to corporate enterprises, circa 1912.

Corporation Source Location Water Grant (cms) Low Stage High Stage Flood Stage Canadian Pacific Railway Bow River At Calgary 57 283 283 Canadian Pacific Railway Bow River Near Bassano 28 85 142 Southern Alberta Bow River Near Carseland 28 57 57 Land Company S. Sask. River Near Bow Island 28 28

Alberta Land Company Bow River Near Carseland 14 14 Alberta Railway and St. Mary River SE of Cardston 14 57 57 Irrigation Company Belly River Near Mtn. View 14 14 14 Milk River Near Milk River 14 42 42

12 2. The Adjustment Years: 1920 to 1950 The years 1920 to 1950 provided a challenging proving ground for the fledgling irrigation enterprises and ultimately led to a number of adjustments in legislation, administrative procedures and financial management of irrigation projects. This period saw most irrigation projects become farmer-owned irrigation districts, and set the stage for hands-on involvement of the federal and provincial governments in irrigation development and management. Generally, returns on the pre-1920 corporate investments were discouraging. Collections from irrigation water users fell short of the funds needed to cover construction, operation and maintenance costs. Land sales were much slower than expected. Administration of the projects was cumbersome and onerous, due to the large number of individual contract holders and the difficulty in collecting the assessed water rates. In 1914, the province passed the Irrigation Districts Act to relieve some of the burden to water suppliers of administering contracts with individual producers. The Act also provided the mechanism for cooperative, farmer owned, financed and operated irrigation projects. The Taber Irrigation District was the first established under this legislation. Several others were quick to follow (Table 2). While the creation of the irrigation districts relieved some of the administrative burden to water suppliers and led to the development of new projects, the economics of irrigation farming remained a serious issue. Irrigation producers could not pay the assessed rates. On some projects, producers demanded their lands be reclassified for dryland agriculture. Capital and operating losses mounted. Most projects continued to operate only with financial assistance from the founding corporate enterprises and/or the governments of Canada and Alberta. Despite the problems encountered, however, most people recognized the overall benefits irrigation could bring (Figure 3).

Table 2. Establishment of the existing irrigation districts in southern Alberta.

Irrigation District Year First Comments Established Water Taber 1917 1920 Water supplied through St. Mary River system. Lethbridge Northern 1919 1923 United 1921 1923 Mountain View 1923 1931 Raymond 1925 1900 Water supplied through St. Mary River system. Magrath 1926 1900 Water supplied through St. Mary River system. Eastern 1935 1914 First water through CPR works. Leavitt 1936 1944 Extension of Mountain View system. Western 1944 1907 First water through CPR works. Aetna 1945 1959 Extension of Mountain View and Leavitt system. Ross Creek 1949 1954 St. Mary River 1968 1900 First water through Canada Land and Irrigation Co. works.

Bow River 1968 1920 First water through Canada Land and Irrigation Co. works.

13 Few residents of Calgary realize the great importance to this city of irrigation with respect to existing systems and the development of future districts, already planned and in some instances surveyed. The accompanying map illustrates vividly the huge areas of central and southern Alberta, portions of which are either already under irrigation or susceptible of irrigation. With irrigation, enormous areas now suffering from the haphazard chances of rainfall will be brought into assured production. Obviously, all land in any project cannot be irrigated but the portions which can be, in effect, provide offset insurance against failure on those sections which cannot be brought “under the ditch.”

Figure 3. Benefits of irrigation and ambitious development plans touted in 1924 newspaper.

14 The province established several commissions to address the problems facing the struggling irrigation districts. The commissions pointed the way to various measures of reform. These included the following. ! Relieving the irrigation water users from responsibility for capital works debt. Corporate entities and the senior governments shouldered large portions of capital costs. ! Greater government financial responsibility, recognizing that the benefits of irrigation go beyond the farm gate. ! Cancellation of water contracts and reclassification of land where irrigation was of marginal value. Some projects were reduced in size. ! Payment schedules more in keeping with producer ability-to-pay. ! Smaller land parcels and more intensive irrigation management. ! Aggressive colonization programs. ! Encouragement of higher value crop types. ! Educational programs and technical assistance. With numerous administrative adjustments and financial assistance from the founding corporations and the two senior governments, the districts endured. By 1950, the era of corporate irrigation enterprises was over. Eleven of the current 13 irrigation districts were established and operating. The remaining two districts, Bow River and St. Mary River, were formally established in 1968. In 1946, the Alberta Irrigation Projects Association was founded to provide a single voice for the districts in dealing with the public or government on issues common to all or most districts. The period 1920 to 1950 provided a severe proving ground for the farmer-run irrigation districts. Challenging circumstances faced by the newly formed districts included the following. ! Inadequate information on soil, climate and market conditions necessary to support profitable irrigation enterprises. ! Pre-1920, unrealistic expectations of financial returns. ! Dryland farmers inexperienced in irrigation techniques became irrigation farmers. ! Crash of the economy and of commodity prices in the 1930s. ! Transfer of responsibility for administration of natural resources from the federal government to the provinces. ! Shortages of capital and labour during World War II. By 1950, the farmer-run organizations appeared to be the most durable and effective administrative bodies for day-to-day management of irrigation projects. About 182,115 hectares were being irrigated within the areas of the current irrigation districts by that year. Only one water licence was issued for the irrigation of lands within the current 13 irrigation districts in the 1920 to 1950 period – to the Canadian Pacific Railway in 1921. The licence was for irrigation of land that is now within the Western Irrigation District. Diversions to other irrigation districts and projects were made under other types of authorization.

15 3. Rehabilitation and Expansion of the Delivery Systems: 1950 to 1970 The 1950 to 1970 period saw the direct involvement of the federal and provincial governments in irrigation development and management, and subsequent large expenditures for the rehabilitation and expansion of the irrigation infrastructure. Throughout the adjustment years, funding for rehabilitation of works had been limited, and in some cases maintenance was neglected. Major construction work was required to bring the water delivery systems up to standard and to enlarge the systems where expansion was contemplated. Interest in the resettlement of drought-stricken farmers and returning war veterans on irrigated lands was an additional incentive for involvement of both the federal and provincial governments in irrigation development. The creation of the Prairie Farm Rehabilitation Administration (PFRA) in 1935 had initiated an era of increased federal government involvement in the development of water delivery systems for irrigation. Initially, PFRA assisted in keeping projects operating by providing subsidies for critical rehabilitation and maintenance. The agency became a major developer in 1950, when the federal government signed an agreement with the province committing to construct and operate the main water storage and delivery works associated with the St. Mary Project. These works included the St. Mary, Milk River Ridge and Waterton Reservoirs, the Belly River diversion, and the Assessed Area connecting canals. On the same project, the province committed to undertake major The irrigable area of rehabilitation and expansion work between the Milk River Ridge Reservoir and land within the Medicine Hat. districts for which a water rate has been The federal government also purchased all assets of the Canada Land and Irrigation levied. Company in 1950. PFRA, in cooperation with the province, began rebuilding and enlarging the main water delivery system and increasing storage for the present-day Bow Actual Irrigated Area River Irrigation District. Both governments were involved with developing new The area that receives irrigation blocks for resettlement purposes within the Bow River and other irrigation water at least once districts. during the growing By 1970, both the province and the federal government had been involved in season. rehabilitation and expansion of water delivery works within almost all of the 13 districts. The area assessed for irrigation within the districts had grown to almost 280,000 hectares (Figure 4). In contrast to the previous 30-year period, the 1950 to 1970 period can be characterized as one of increasing stability and modest growth. The willingness of the two senior governments to assume some responsibility for 500 the continued success of the projects provided irrigation farmers with increased 400 Assessed assurance their water supplies would not be suddenly cut off due to structural failure or 300 bankruptcy of the operating Actual agency. In 1963, water licences 200 were issued to the Eastern, Lethbridge Northern, United and Western irrigation districts.

Irrigated Hectares (thousands) 100 In each case, the water use priority dated back to the 0 application for a water licence. Diversions to other districts 1910 1920 1930 1940 1950 1960 1970 1980 1990 Year were made under other Figure 4. Growth of irrigation within the 13 irrigation districts of Alberta. authorities.

16 4. Provincial and Irrigation District Control: 1970 to Present Major changes in the irrigation industry have taken place since 1970. Direct, hands-on involvement in irrigation development and management has been transferred from the federal government to the province and the irrigation districts. Major improvements in infrastructure and technological advances have led to unprecedented rapid growth in irrigation area and to efficiency improvements. Above all, the period marks the emergence of the irrigation districts as progressive, forward-thinking entities, seeking to enhance the social and economic standing of their members and the southern Alberta community-at- large through sustainable agriculture. By 1970, the federal government had accomplished its primary objectives of stabilizing and expanding irrigated agriculture in southern Alberta and resettling drought-stricken farmers and war veterans. It was prepared to relinquish its direct role. Through a 1973 agreement with the Alberta government, the federal government withdrew from hands-on management of irrigation projects and transferred all federal interests in irrigation works within the Bow River and St. In years of heavy precipitation Mary River developments to the province. In addition, the province assumed the irrigated area drops, greater responsibility for management and improvement of irrigation particularly in the western- infrastructure through several initiatives, as outlined below. most districts where moisture ! deficit is normally low. In such In 1969, funding was announced to assist the irrigation districts to years, irrigation water users rehabilitate and expand aging water distribution works within the districts. may feel natural moisture is Under this cost-share program, the districts paid 14% of the construction sufficient for good crop yields. costs and the province (AAFRD) paid 86%. The distribution of costs In some districts, older approximately reflected the distribution of benefits to the irrigation assessments provide producer and to the region, province and country (Rogers et al. 1966). This permanent water rights for cost-share program was reaffirmed and extended for five years in 1975, small parcels of 12 to 16 and has been extended several times since 1980. The cost-sharing ratio hectares that cannot be was changed from 86/14 to 80/20 in 1994, and to 75/25 in 1995. Work is economically irrigated by continuing under the 1995 cost-sharing formula. today's methods. The owners of such parcels may use the ! In 1975, the province announced a policy whereby AENV would assume water for domestic or stock responsibility for rehabilitation, operation and maintenance of the major watering purposes, and irrigation headworks. (Headworks are loosely defined as the works therefore continue to pay their required to divert water from sources and convey it to the districts.) The water rates to ensure objective of provincial ownership was to maintain a secure and continuous deliveries. Cultural practices supply of water for the districts and all other uses, and to operate the (such as crop rotations) and projects for multi-purpose use. Agreements with districts were negotiated, individual producer social and and Alberta Environment took over responsibility for all headworks except economic factors may also contribute to the discrepancy those for the EID and UID. between assessed and actual ! Also in 1975, AENV introduced a 10-year program for rehabilitating the irrigated areas. headworks and the main irrigation district canals. In 1980, the province announced a 15-year extension of this program. Work on the program is nearing completion under Alberta Transportation. ! In 1980, the province announced a water storage project would be constructed on the Oldman River. Construction of the Oldman River Dam was initiated in 1986 and completed in 1992. The irrigation districts experienced unprecedented growth during the decade from 1970 to 1980 (Figure 4). The area on the assessment rolls increased from 279,877 hectares in 1970 to 419,730 hectares in 1980 – an increase of 50%. This was due, in large part, to the growing popularity of sprinkler irrigation, in particular centre pivot sprinklers. Sprinklers greatly reduced irrigation manpower requirements and increased the area that could be supplied with water from the distribution network. The assessed area in 1999 was 524,528 hectares.

17 While rehabilitation is incomplete, for the most part the irrigation infrastructure has been modernized and is in good condition. The irrigation districts are well established and operating as progressive enterprises. A variety of water uses are integrated into their developments and operations and they provide dependable water supplies to their irrigation farmers and to communities, industries, livestock, domestic users, recreation users and wildlife conservation projects within their areas. Crop diversity and value-added commercial enterprises are encouraged and are increasing within the districts, contributing to the regional economic well-being. The districts are well informed of and responsive to current water management issues. They are aggressively gathering data and developing sophisticated analytical tools to better address environmental, water conservation and operational issues within their respective districts. The new Irrigation Districts Act, passed by the Alberta government in April 1999, provides the districts with more autonomy in decision making, more independence from government, and, of course, more responsibility and accountability to their water users. The districts are working together, and collectively are well-positioned to meet the challenges facing them as a result of changes in the Act. The Alberta Irrigation Projects Association (AIPA), established in 1946, continues to be an active and respected voice for the 13 irrigation districts. AIPA's primary focus in recent years has been to increase public and political awareness of the wide-ranging benefits of irrigation, and the importance of upgrading and maintaining a modern and efficient network of irrigation infrastructure. AIPA accomplishes its objectives through a variety of means, such as publishing newsletters, hosting conferences, presenting briefs in public forums, and through representation on committees addressing environmental, legislative, and agri-economic issues. Twenty-one new licences were issued to the irrigation districts in this period – seven in the 1980s and 14 in the 1990s (Table 3). The total volume of water licensed to the 13 districts is 3,434,559 cubic decametres. By August 1999, there were more than 110,000 hectares of private irrigation licensed in Alberta, with an allocation of about 375,000 cubic decametres. The total allocation for irrigation in Alberta would be in the order of 3.8 million cubic decametres. This allocation contrasts with the so-called "water grant" of over 8.6 million cubic decametres noted by F.H. Peters, Commissioner of Irrigation, in his 1912 report on irrigation. Ninety years after Peters made that statement, Alberta has actually licensed only about 45% of the volume of the grant. Of the 26 licences that have been issued to the 13 irrigation districts (including two that have been superceded), one was issued by the federal government under the Irrigation Act, and the remaining 25 were issued under the provincial Water Resources Act. As such, none of the existing licences have expiry dates. The new Water Act recognizes licences issued under the predecessor Acts, and protects their original priorities, terms and conditions, and all rights of the holders of those licences.

18 Table 3. Water licences for irrigation districts in Alberta.1 Licence Date Licence 2 Notes District Issued Water Source Priority Volume (dam3 ) 1) This table is intended for general information Aetna May 15, 1992 Belly River 1945063001 6,784 only. Its contents should not be used for Dec 7, 1992 Belly River 1991122301 4,317 purposes of interpreting and applying the law.

3 The legislation and the licences should be Bow River Dec 30, 1982 Bow River 1908102702 185,025 consulted for these purposes. 1913032501 185,025 All licences have conditions attached to 1953062501 98,680 them. For instance, some licences are subject to Oct 31, 1996 Bow River 1992020510 86,345 instream flow conditions; others are not. Some are subject to instream flow conditions that may Eastern Jan 4, 19634 Bow River 1903090402 939,927 be established in the future. Some of the licences are subject to "stage" Leavitt Jun 18, 1992 Belly River 1939061701 9,560 constraints on the source stream. Low stage is Dec 8, 1995 Belly River 1991123004 5,242 the period when the flow is less than the long- term median during the irrigation season. High Lethbridge Jan 8, 19635 Oldman River 1917111601 185,025 stage is the period when the flow is greater than Northern Mar 25, 19826 Oldman River 1917111601 185,025 the median but less than the 15% exceedence flow. Flood stage is the period when the flow is 1974110401 82,645 greater than the 15% exceedence flow. The 15% Aug 27, 1992 Oldman River 1982041501 61,675 exceedence flow is the flow that is expected to Dec 7, 1992 Oldman River 1991082301 61,675 be equalled or exceeded not more than 15% of the time during the irrigation season. Magrath Nov 26, 1982 St.Mary River 1899020704 11,324 2) Priority is based on the date of application St.Mary River 1950053108 5,329 for a licence. The priority number represents the Waterton River 1950053109 16,652 year (bolded), month and day of the application. The last two digits prioritize same-day Belly River 1950053110 3,701 applications. Dec 7, 1992 SM, W, B* 1991082204 4,934 3) The BRID 1982 licence includes headworks evaporation losses. Mountain Dec 22, 1988 Belly River 1923071003 9,251 4) In the EID 1963 licence, of the total View Dec 7, 1992 Belly River 1991121702 617 allocation, 246,700 dam³ is for diversions outside the "irrigation season," May 1 to Sept Raymond May 10, 1983 St.Mary River 30. The maximum rate of diversion during the 1899020703 15,098 irrigation season is subject to Bow River stage: St.Mary River 1950053114 15,431 Low Stage 28 cms; High/Flood Stages 85 cms. Waterton River 1950053115 30,529 The diversion rate during the non-irrigation Belly River 1950053116 6,784 season is not to exceed 23 cms**. Dec 7, 1992 SM, W, B* 1991082302 32,071 5) For the LNID 1963 licence, the maximum rate of diversion was subject to Oldman River Ross Creek Apr 26, 1989 Gros Ventre Cr 1951030201 3,701 stage: Low Stage 20 cms; High/Flood Stage 23 cms**. 6) The LNID 1982 licence replaced the 1963 St. Mary Sept 24, 1991 St.Mary River 1899020701 207,441 licence. River SM, W, B* 1950053107 409,309 7) For the UID 1963 licence, the maximum rate Dec 7, 1992 SM, W, B* 1991082309 273,837 of diversion is subject to Belly River stage: Low Stage 5 cms; High and Flood Stage 10 cms. Taber Aug 27, 1982 St.Mary River 1899020702 41,939 8) For the WID 1921 licence, the maximum rate St.Mary River 1950053117 41,322 of diversion was subject to Bow River stage: Waterton River 1950053118 83,261 Low Stage 59 cms. High/Flood Stage 64 cms**. Belly River 1950053119 18,503 9) For the WID 1963 licence, the maximum rate Dec 7, 1992 SM, W, B* 1991082602 9,868 of diversion is subject to Bow River stage: Low Stage 11 cms, High Stage 17 cms; Flood Stage United Jan 14, 19637 Belly River 1919032401 62,909 21 cms**. Mar 13, 1996 Waterton River 1993051701 20,970 The WID 1963 licence replaced the 1921 licence and reduced the allocation. The WID Western Sept 21, 19218 Bow River 1903090401 773,624 does not believe it consented to this change and 9 is disputing the right of the province to reduce Jul 2, 1963 Bow River 1903090401 197,853 the allocation. *SM,W,B=St.Mary River, Waterton River, Belly River; **cms = cubic metres per second.

19 B. SOUTH SASKATCHEWAN RIVER BASIN WATER MANAGEMENT POLICY Rapid expansion of irrigation during the 1970s and growing interest in environmental issues led to concerns about the limits of the water supply in the SSRB. Irrigation water supply shortages became noticeably more frequent, particularly on uncontrolled streams. At the same time, public concern about environmental issues was becoming more prominent. In the early 1980s, Alberta Environment initiated a process to address water management policy issues in the SSRB. The process included the following. ! The SSRB planning program, culminating in the Summary Report (Alberta Environment 1984). ! Public hearings conducted by the Alberta Water Resources Commission. ! The Commission's report and recommendations (Alberta Water Resources Commission 1986). ! Policy development and Cabinet approval. The SSRB Water Management Policy was announced on May 28, 1990 (Alberta Environment 1990). It provided guidelines related to: ! Multi-purpose use of water; ! Priority of uses, and minimum and preferred instream flows; ! Irrigation expansion; ! Administration of the Prairie Provinces Water Board Agreement; ! Water conservation; and ! Public consultation. The policy is used to guide water management and allocation decisions in the SSRB.

20 C. IRRIGATION EXPANSION GUIDELINES The 1990 SSRB Water Management Policy called for establishing the maximum amounts of water that can be allocated for irrigation, with due consideration for the needs of all other users, including instream users and interprovincial apportionment. Alberta Environment worked with other government agencies to establish the guidelines. The process considered the following. ! Alberta Water Resources Commission recommendations on the location and magnitude of irrigation expansion. Their recommendations took into consideration extensive public input. ! SSRB Water Management Policy statements related to instream flow needs and interprovincial apportionment commitments. ! The results of computer simulation modelling. ! Information on irrigation expansion desires provided by existing and potential irrigation farmers. ! Consultations with Irrigation Council, individual irrigation districts, and existing and potential private irrigation water users. ! Discussions with Members of the Legislative Assembly and government committees. The guidelines were approved by Order-in-Council on September 20, 1991. They are defined in and are being implemented through the South Saskatchewan Basin Water Allocation Regulation (Alberta Environment 1991) pursuant to Section 173 of the Water Act. Recognizing the limitations of the databases and estimates of current and future water uses, the government committed to reviewing and refining theRegulation in 2000. TheRegulation states that the amount of water allocated to each expansion area must not exceed the amount sufficient for the irrigation of a specific maximum area for each of the 13 irrigation districts. The maximum area for each district is shown in Column (8) of Table 4. For licensing purposes, the volumes of water considered to be sufficient for the irrigation of the maximum areas for each of the districts were determined by AENV and AAFRD. Referring to the columns in Table 4, the following criteria were used to determine the licensing volumes for administration of the Regulation.

21 3

Act

3,701

9,868

11,102

83,878

41,939

14,802

99,914

(10)

1999

197,853

194,893

555,075

939,927

890,587

(dam )

Licence

Volumes

3,434,559

fer from the

3,701

9,868

11,102

83,878

(9)

41,939

14,802

99,914

342,913

194,893

918,958

619,217

890,587

391,020 391,020

(dam )

Licence

3,622,792

Volumes

Regulation

486

1,497

7,406

1,930

1,429

(8)

67,583

84,984 38,445

18,818

33,265

13,759

(ha)

111,289

Area

150,543

531,434

Limit

Limit = 535,886 ha.

Irrigation

591

894 683

586

728

776 567

579

761

762

826

645

609 531

Regulation

(7)

Total

(mm)

Demand

Projected

Diversion

91 91

52 52 52

(6)

. The area limits have been revised in the Irrigation Districts

Projected

Total adjusted 1999

Regulation

61 61

(5)

503

347

189 399

186

1990

circa

Return Flow (mm)

9 9

6 6

(4)

(mm)

Losses

Reservoir

Evaporation

73 43

98 88

(3)

305

207

219

Projected

15,740 ha. Other districts have minor adjustments.

licence volume, the allocation was based upon the best available information on water requirements, and may dif

76 46

(2)

113

128

168

232

366

244

1990

Canal Losses (mm)

circa

ea limits and licence volumes.

Regulation

licence volumes given in the table are as established for the 1991

463

485

555

457

457 457 457

479

442

576

436

686

500

(1)

(mm)

Farm

irrigation ar

Demand

Optimum

Irrigation

Regulation

The revised limit for the EID is 1

Regulation

licence volume.

View

Irrigation District

Eastern Western Weighted Means Leavitt Taber United Totals Aetna Bow River Lethbridge Northern Magrath Mountain

Raymond

Ross Creek

St. Mary River

for some districts.

Regulation

Section II.C. of the text outlines the criteria used in deriving the data in each column of the table. For districts not yet licensed to the

The area limits and

Table 4. 1991 22 Column (1): The optimum farm demand was based on the following guidelines. ! Crop mixes similar to the pattern for 1987 to 1989 within each district. ! The optimum crop requirement was considered to be the amount of water necessary to maintain moisture in the root zone above 50% of field capacity. The full optimum requirement was used to determine the licensed volume. Typical on-farm irrigation management practice circa 1990 used about 80% of optimum. ! The full growing season precipitation plus 20% of the non-growing season precipitation would effectively contribute to moisture within the root zone. ! The 90th percentile irrigation demand was assumed for computing the proposed licensing volume. The 90th percentile demand would be expected to occur under high temperature and low precipitation conditions. Over a long period of time, it would be exceeded in only 10% of the years. ! An on-farm irrigation application efficiency of 75% for all crops and all districts. Column (2): Circa 1990 canal water losses were estimated using the "Moritz" formula (Alberta Agriculture 1990). Distinctions were made between rehabilitated and un-rehabilitated canals in terms of velocity of flow (0.61 metres per second for rehabilitated; 0.46metres per second for un-rehabilitated) and water loss per wetted area (0.00170 cubic metres per day for rehabilitated; 0.0116 cubic metres per day for un-rehabilitated). Canal losses shown in Column (2) consider the status of rehabilitation as of 1990, and the canal sizes and lengths unique to each district. Unit canal losses (mm) were computed based on the area limit for each district as shown in Column (8). Column (3): Projected canal water losses were estimated based on the potential for decreasing seepage with continued rehabilitation of the canals. Column (4): Evaporation from reservoirs within the irrigation districts was computed based on the mean surface area of the reservoirs, and the mean shallow lake evaporation, minus the precipitation for the specific geographic locations of the reservoirs. The unit evaporation losses were computed based on the area limit for each district, assuming there would not be a significant change in reservoir evaporation as irrigation expands. Column (4) does not include evaporation losses for storage reservoirs within the headworks system operated by AENV. Column (5): Historical return flows as estimated by Water Survey of Canada for the period 1979 to 1989 were assumed to be indicative of 1990 management practice. Ninetieth percentile return flows are listed. Unit return flows were computed based on actual irrigated hectares. It was assumed the volume of return flow would increase as the irrigated area increases. Column (6): Projected return flows were estimated assuming that district management and infrastructure improvements would reduce return flows by varying amounts within each district. Column (7): The projected 90th percentile unit demand is the sum of the unit values in Columns 1, 3, 4 and 6. Column (8): The irrigation area limit is taken from the South Saskatchewan Basin Water Allocation Regulation which was approved by Order-in-Council on September 20, 1991. Column (9): TheRegulation licence volume demand is based on unit diversion and the irrigation area. Column (10): The licensed amounts within each irrigation district as of July, 1999. Note that only the BRID and WID have licences for volumes that are less than the Regulation licence volumes.

23 In establishing theRegulation , it was assumed irrigation water users could occasionally tolerate applying less than the optimal water requirement. Irrigation performance criteria were developed to evaluate the performance of simulation modelling output for irrigation expansion scenarios. The criteria considered both the magnitude and frequency of shortages from the optimal requirements. The performance of a scenario was considered to be acceptable if both the following conditions were met: ! There was a growing season irrigation deficit equal to or greater than 75 mm in less than 20% of the years in the simulation period; and ! There was a growing season irrigation deficit equal to or greater than 150 mm in less than 10% of the years in the simulation period. Alberta Environment has used the 1991Regulation limits and licence volumes to guide the processing of irrigation water licence applications and the allocation of water in the SSRB. The irrigation districts have worked closely 1991 Regulation irrigation with government to develop the principle that allows the districts to expand area limits and proposed beyond their area limits if improvements in efficiencies and/or reduced return licence volumes - flows allow such expansion within their respective licensed volumes. The Throughout this report, licences fix the amount of water that each district is entitled to divert, subject to reference is made to the priorities, terms and conditions. irrigation area limits that are specified for the irrigation districts in the South D. AENV'S SSRB WATER MANAGEMENT PLANNING PROCESS Saskatchewan Basin Water When theRegulation was established in 1991, the government recognized Allocation Regulation, and that databases and information on some aspects of water needs, particularly the proposed licence volume instream needs, were inadequate to make definitive decisions. Analytical tools developed to assist in for the study of water supply and demand also needed to be improved to more administering the Regulation. accurately represent the physical system and water licence priorities. In its For convenience and decision to establish theRegulation limits and licence volumes, the consistency, the irrigation government committed to review and refine them during the next decade. area limits are referred to as 1991 Regulation limits, Alberta Environment is preparing a water management plan directed toward meaning 531,434 hectares. resolving water management issues in the SSRB, including determining The proposed licence volume instream flow needs for protection of the aquatic environment and the quantity is referred to as the of water available for future allocations. Regulation licence volume, The planning process will involve four multi-sector, stakeholder, basin meaning 3,622,792 cubic advisory committees and consultations with the public-at-large.The first phase decametres. of planning will be devoted to the development of a system for water allocation transfers. Subject to certain conditions, transfers will permit water allocations to be moved to purposes and locations where they are most highly valued. A key goal now is to develop the conditions that will be applied to transfers. The first phase should be ready for implementation by April 2002. The second phase will focus on determining water conservation (instream flow) objectives for each river. This will require an assessment of the volumes required for consumptive demands and the flows required for protection of the aquatic environment. Studies to address these requirements are ongoing. The key goals of the second phase will be to reach compromises between these sometimes competing interests and to make wise choices for management of water resources. The second phase is scheduled for completion by the end of 2002. Additional phases of the plan are yet to be determined.

24 III.

Chapter Scope and Methodology Chapter III. Scope andM ethodology

A. OBJECTIVES The Irrigation Water Management Study Steering Committee was established in 1996 to provide direction to a four-year study of water management within the 13 irrigation districts of southern Alberta. The overall objective of the study was to provide accurate and reliable information on current and future water requirements and to identify irrigation water management practices required for sustainable irrigation within the districts. Sustainable irrigation implies an industry that is economically viable and profitable, and preserves natural resources and the environment for the benefit and enjoyment of future generations. This report, produced by the Steering Committee, details the state of the irrigation industry in southern Alberta, provides key information for AENV's water management planning process in the SSRB, and provides a basis for planning and decision making by government agencies and irrigation districts for the foreseeable future. Specific objectives of the study were as follows. 1) Identify and quantify current irrigation water requirements, uses and efficiencies (on-farm and within the distribution systems) for the irrigation districts. 2) Quantify the changes in water management efficiencies and water use from those used in determining the 1991Regulation licence volumes . 3) Quantify possible future irrigation water use based on: ! changes in cropping types and mixes; ! changes in farm irrigation management;

! improvements in the on-farm and distribution systems infrastructure ":Sustainable development and management; and Development which ensures ! information on leading edge management and equipment from similar that the utilization of irrigation regions in the United States. resources and the environment today does not 4) Assess the potential for irrigation expansion, the associated risks of water damage prospects for their shortages, and the impacts of shortages considering existing irrigation use by future generations.” district licensed and reserved water volumes. 5) Develop leading edge computer tools to simulate district operations and National Task Force on the enable districts to plan and refine operations and improve management of Environment and Economy (1987). water supplies. 6) Identify and quantify the potential contribution of irrigation expansion toward achieving the province's business and fiscal goals. The analytical tools and databases that have been developed enable individual irrigation districts to critically examine their current operations, refine water management practices, and plan for the future. In keeping with their newly- acquired independence under the Irrigation Districts Act, the districts hope to demonstrate to their water users the benefits and risks of expanding irrigation within the constraints of their licensed water allocations. It is hoped that with this information the respective district boards can make informed decisions on the limits of expansion. This information will also be used to demonstrate to the province the merits of additional water allocations for irrigation, should the province's SSRB water management planning process find surplus water is available in the South Saskatchewan River Basin.

27 B. ORGANIZATIONAL STRUCTURE AND FUNDING The Steering Committee was comprised of nine directors of AIPA, representing the 13 irrigation districts, three representatives from Irrigation Branch, AAFRD, and one representative from PFRA (Figure 5). A representative from AENV sat on the committee as a resource and liaison. The committee identified three primary focus areas for research and technical analyses: On-Farm Water Use; Distribution System Efficiency; and Computer Modelling. Working groups were formed to coordinate research and studies in each of the focus areas. Work was conducted by the staff of the irrigation districts, the Irrigation Branch, and AENV. In total, these agencies contributed more than $2.1 million in complementary, in-kind services. Outside consultants were retained to undertake specialized tasks for the project. Funding for consulting services and instrumentation was provided by AAFRD, PFRA, and the irrigation districts, through AIPA. The irrigation districts invoked a special acreage levy to raise the required funds from their water users. In total, about $770,000 in funding was contributed by the three agencies, primarily for consulting services. During the course of the work, some of the irrigation districts contributed hundreds of thousands of dollars toward flow monitoring stations within their distribution systems and on return flow channels. In most cases, funding was provided through 75/25% province/district cost sharing under the Irrigation Rehabilitation Program. The data from these stations contributed greatly toward the Irrigation Water Management Study. Work on the program was initiated in 1996 and was completed in 2001.

28 Irrigation Water Management Study Steering Committee

On-Farm Distribution Modelling Working Group Working Group Working Group

Water Application Efficiency Intensive Block Studies Irrigation District Model Crop Water Use Distribution System Losses - Irrigation Requirements Module Current Irrigation Management - Return flow - Network Management Module On-Farm Irrigation Systems - Evaporation Water Resources Management Model Water Deficit Risk Analysis - Seepage Agro-Climatic Database Development Infrastructure Inventory

Study Agencies: Alberta Irrigation Projects Association Alberta Agriculture, Food and Rural Development Agriculture and Agri-Food Canada, Prairie Farm Rehabilitation Administration Alberta Environment Consultants

Steering Committee Membership Brent Paterson Alberta Agriculture, Food and Rural Development, Co-Chairman Stan Klassen Alberta Irrigation Projects Association, Co-Chairman Rod Bennett Alberta Agriculture, Food and Rural Development (former member Allan Herbig) Wally Chinn Alberta Agriculture, Food and Rural Development Andrew Cullen Agriculture and Agri-Food Canada, Prairie Farm Rehabilitation Administration Earl Wilson Eastern Irrigation District Jim Brown St. Mary River Irrigation District Kevin Haggart Lethbridge Northern Irrigation District (former member Rick Ross) Keith Francis Taber Irrigation District Gordon ZoBell Raymond Irrigation District Andy Strang Aetna Irrigation District Henry Holst Bow River Irrigation District Jim Webber Western Irrigation District Doug Clark Alberta Environment (resource and liaison)

Figure 5. Organizational structure for the Irrigation Water Management Study.

29 C. COMPONENTS OF THE IRRIGATION WATER MANAGEMENT STUDY 1. On-Farm Working Group The On-Farm Working Group's overall objective was to refine estimates of crop water requirements, current irrigation water use and probable irrigation water use in the future, and to assess impacts of water shortages on crop production and financial returns to producers. The task was addressed in five component studies as outlined below. a) Agro-climatic Database Development Databases of climate or weather parameters that are fundamental to the understanding of crop water use and irrigation water requirements are commonly referred to as agro-climatic databases. They may be comprised of primary parameters, such as temperature, precipitation, wind speed and direction, and solar radiation, as well as calculated parameters, such as corn heat units and evapotranspiration. Weather information in Alberta is collected by a number of agencies in different locations, for a variety of purposes. Using data from numerous sources, Environment Canada's Atmospheric Environment Service and Agriculture and Agri-Food Canada's Research Branch worked together to develop a systematic grid of weather data points across the Canadian prairies. This database, called the Gridded Prairie Climate Database (GRIPCD), is designed as a common source of baseline information available for use by researchers and practitioners involved with agriculture and climate change. The grid points are spaced at 50 km intervals. However, the GRIPCD database does not include potential evapotranspiration, a parameter of key importance for the determination of irrigation water requirements. The primary objective of this component of the Irrigation Water Management Study was to develop a database to complement GRIPCD that would provide a basis for daily, crop-specific evapotranspiration computations for the period 1920 to 1995 for the irrigated area of southern Alberta. Databases for growing season precipitation, net moisture deficit, corn heat units, and frost-free periods were also developed. The task involved reviewing various equations for computing evapotranspiration for a high water use crop similar to alfalfa, selecting the equation that best correlated with research data, and computingevapotranspiration at the grid points using GRIPCD data and derived data where information gaps existed. Maps showing the distribution ofevapotranspiration and other agro-climatic parameters throughout southern Alberta were prepared. The expanded GRIPCD database was used to estimate irrigation demands and losses for computer modelling. b) Crop Water Use Crop water requirements for irrigation in southern Alberta have been determined based on field monitoring and research conducted in the 1960s and 1970s, with the prevailing irrigation management and technology. Irrigation systems and management practices have since changed, and new crop varieties have emerged. The working group updated crop water use data based on the current state of irrigated agriculture. Alfalfa is grown on more irrigated land than any other crop, and is the largest water consumer. It was selected to represent high water use crops in southern Alberta.

30 Research plots, using an emerging alfalfa variety, were developed at three sites: Picture Butte, Bow Island and Rolling Hills (Figure 6). Several different irrigation management regimes, representing advanced irrigation technologies, were tested in four replicated, randomized plots. Five irrigation water treatments were used, each treatment initiating and ceasing irrigation when soil moisture in the root zone met various percentages of field capacity. Water rationing was considered in two of the five treatments. Neutron probe readings were taken to measure soil moisture conditions and water use throughout the growing season. Water wells were established to monitor deep percolation beyond the root zone. Crop yields for each water treatment were determined based on a three-cut system of harvesting. The program included soil classification, soil sample analyses, and determination of soil moisture holding capacities. Root mass and development were determined for each water treatment. Results of this work were used to improve estimates of crop water requirements for computer modelling.

N RED DEER

RIVER

DEER RED DEER RIVER BASIN

RED

R O Drumheller SE K B RED E U E D R British Columbia RIVER DEER C Saskatchewan

RIVER

BERRY

RIVER Strathmore

ELBOWCALGARY BOW RIVER BOW RIVER BASIN RIVER Brooks ER RIV

LITTLE HIGHWOOD

BOW

SASKATCHEWAN RIVER WILLOW MEDICINE SOUTH HAT OLDMAN OLDMAN RIVER Vauxhall CREEK BASIN Picture ANRIVER RIVER Butte OLDM Bow Island Taber Coaldale CRO WSN LETHBRIDGE SOUTH SASKATCHEWAN EST R. RIVER SUB-BASIN R.

E L T RIVER RIVER S A Y L C L E R. B

R MARY M E ILK RIV

WATERTON ST. Montana

Alfalfa research plots Figure 6. Locations of alfalfa research plots.

31 c) Irrigation Water Management Practices Past studies have noted that irrigation water users were applying less water to their crops than required for optimum production. However, it was believed this practice was changing as technology improved. The objectives of the irrigation water management practices component of the study were to obtain an indication of the extent to which contemporary irrigation water applications compare with that required for optimum production, and to estimate possible ultimate irrigation applications with further improvements in on-farm management. Monitoring sites were established on approximately 60 fields each year (Figure 7). Sites were selected to provide a cross-section of grain, forage, oilseed and specialty crop types, a variety of irrigation systems, and a random selection of irrigation managers. The intent was to conduct monitoring without influencing the normal irrigation management decisions of the producers. Monitoring was conducted from 1996 to 2000.

N RED DEER

RIVER

DEER RED DEER RIVER BASIN

RED

ROSEBUD Drumheller RED

British Columbia RIVER DEER CREEK Saskatchewan Y

RIVER

BERR

RIVER Strathmore

ELBOWCALGARY R BOW RIVER E BOW RIVER BASIN RIV Brooks

RIVER AN

LITTLE HIGHWOOD TCHEW

BOW

SASKA RIVER WILLOW TH MEDICINE SOU HAT O L OLDMAN RIVER Vauxhall D M CREEK A BASIN N Picture RIVER RIVER Butte OLDMAN Bow Island Taber Coaldale CROWSNEST LETHBRIDGE SOUTH SASKATCHEWAN R. RIVER SUB-BASIN

R. R E ER IV RIV R

CASTLE R. BELLY

R MARY MILK E RIV

WATERTON ST. Montana Monitoring Sites 1996 1998 1997 1999

Figure 7. Irrigation management monitoring sites.

32 Parameters monitored included: ! Field soil moisture; ! The timing of irrigation events and the quantities of water applied; ! Agro-climatic data, including precipitation, maximum and minimum temperature, solar radiation, humidity, and wind travel; and ! Crop yields. UMA Engineering Ltd., Calgary, was retained to conduct a literature search of current irrigation management strategies from recognized institutions and agencies across North America. The information was used to compare irrigation water requirement values used in Alberta with those across North America, and to provide insight into leading edge technology and irrigation water management that may be applicable to Alberta in the future. d) On-Farm Irrigation System Efficiencies The total quantity of water diverted by an irrigation district is highly influenced by how efficiently irrigation farmers apply the water to the land for use by the crop. Improvements in on-farm efficiency offer significant potential for freeing up a portion of licensed quantities for expansion of the irrigated area. Key factors affecting on-farm efficiency are irrigation methods, the types of irrigation equipment used, and on-farm management practices. AAFRD has maintained an inventory of on-farm irrigation methods and equipment since 1981. This database has recently been modernized and expanded through involvement of irrigation district staff and the use of electronic data collection and retrieval equipment. The efficiencies of conventional on-farm equipment have been estimated, based on monitoring, literature searches and experience. Modern equipment with improved technologies has become increasingly efficient. On-farm equipment choices can offer significant water saving opportunities. Intensive field testing of several centre pivot sprinkler systems with various types of emerging equipment was conducted to determine "ultimate" water application efficiencies. Efficiencies of leading-edge equipment were compared to that of conventional systems to determine potential water gains. The project was conducted with participation of a local irrigation equipment dealer and the Blood Tribe Agricultural Project. A variety of application devices were installed on centre pivot systems for testing at 12 sites. Sites were located on typical level and sloping topography. Agro-climatic and soil moisture conditions were monitored. The net beneficial catch of water within the root zone was determined. A literature search was conducted to update the information base on North American irrigation systems and trends. e) Risk Assessment Major incentives for expanding irrigation are to improve the viability of individual farming enterprises, to increase the efficiency and economic viability of irrigation districts, and to contribute to the economic and social objectives of the province. As irrigated areas expand within districts, the risk of water shortages to individual users may increase. When shortages are experienced, there will be reductions in crop yields and/or quality, and associated reductions in economic returns. There could also be secondary impacts on value-added industries.

33 The objective of the risk assessment component was to develop a computerized Farm Financial Impact and Risk Model (FFIRM) that would enable an analyst to examine the economic impacts of a variety of water shortage scenarios, coupled with a variety of on-farm operational and financial characteristics. A range of water shortage scenarios was provided as output from the Irrigation District Model (IDM) and the Water Resources Management Model (WRMM). Key characteristics of water shortages defined in output from the models were considered in the risk assessment. These included magnitude, frequency, duration (number of consecutive years of shortages), and timing of shortages. An irrigation management factor that recognized the degree to which water applications by irrigation water users compared to that required for optimum yields was also used in the risk analysis. It was essential that the FFIRM be sensitive to a variety of agricultural production, operation and farm financial circumstances which could be specified as input values. These include: ! Agro-climatic conditions; ! Irrigation water supply characteristics; ! Crop mixes; ! On-farm irrigation systems; ! Energy sources; ! Farm equity conditions; ! Crop prices; ! Crop production costs; and ! Target crop yield or expectations. Output from the FFIRM included yield, quality and economic value of farm production, production costs, and impact on farm operations. Information generated by this model can be used by individual irrigation districts to make difficult management decisions related to irrigation expansion and operations within the districts. These decisions may involve compromises and trade-offs related to matters such as water supply security, financial risk, water rationing, and distribution of impacts.

2. Distribution Working Group The overall objective of the Distribution Working Group was to determine the physical and operational characteristics of infrastructure within the irrigation districts, and to identify and quantify opportunities for continued improvements in water management efficiencies. The results of this work were needed to calibrate the IDM and to provide insight into the ultimate water savings that could be realized through infrastructure improvements and operational adjustments within districts. The task was addressed under four component studies as outlined below. a) Irrigation Block Studies Two irrigation blocks were established and fitted with a variety of monitoring equipment to record inflows to and outflows from the blocks, and flows to and from individual farm units within the blocks.

34 Block K5 was established within the BRID in 1994 (Figure 8). It has an area of 1,467 hectares, about half of which is irrigated by surface methods and half by sprinklers. Block J12, with an area of 1,435 hectares, was established within the LNID in 1995. It is irrigated entirely by sprinkler systems. Data collected included crop type, on-farm irrigation system, field area, weather, canal capacities and farm management characteristics. Flow data were collected at 20-minute intervals at turnouts, drains and spill channels. Inflows and outflows were monitored on two larger blocks, Block B in the BRID and Block K in the LNID, to further assist in calibrating the IDM. Each of these larger blocks contain within them the more intensively monitored smaller blocks. Information from all blocks was used to relate area irrigated, on-farm water management, and irrigation methods and systems to flows within the distribution systems. Model output was compared with recorded flows and appropriate calibration adjustments were made. b) Canal Seepage Seepage from canals is wasteful. More importantly, it may lead to waterlogging and/or salinity of productive agricultural lands. The Moritz formula, recommended by the United States Bureau of Reclamation, was used to determine the canal seepage component of water allocations associated with the 1991Regulation . However, it was felt that local research could improve the estimates of seepage losses. Ponding tests were conducted to provide estimates of seepage losses that could be expected from both rehabilitated and unrehabilitated, unlined, earthen canals.

Canal

Pipeline 36 31 Drain Turnout Bow River D5 Hydrometric station Irrigation District

26 25 30 Block K5

D7 N D10 Enchant

Vauxhall

22 23 24 19

Lethbridge Northern D5 Irrigation District 16 15 14 13 18 L16 L2 Block 526 J12

Figure 8. Intensively monitored Block K5 in the BRID.

35 A literature search was carried out to compile information on seepage coefficients and to guide field testing procedures. Twenty-nine ponding test sites were carefully selected to represent a variety of typical soil conditions and canal characteristics (Figure 9). Tests involved constructing earth plugs at the ends of 150-metre long canal sections. The isolated sections were filled with water to their operational depth. Water levels were recorded for five to 22 days. The drop in water level was adjusted for evaporation and precipitation, and seepage was computed in terms of cubic metres of water lost per square metre of wetted area per day. This can be reduced to metres per day. The computed seepage losses from the test sites were used to estimate seepage losses in each of the 13 irrigation districts based on the inventory of canal characteristics and soil texture. It was assumed seepage would be zero for canals with plastic lining and for pipelines.

N RED DEER

R E IV R

DEER RED DEER RIVER BASIN

RED

R O Drumheller SE B U RED D

RIVER D CREEK Saskatchewan British Columbia E E R RIVER

BERRY

RIVER Strathmore

ELBOWCALGARY BOW RIVER BOW RIVER BASIN RIVER Brooks

N RIVER A

E L IT HIGHWOOD T CH L T E

BOW SKA

SA RIVER WILLOW TH MEDICINE SOU HAT O L OLDMAN RIVER Vauxhall D M CREEK A BASIN N Picture RIV RIVER Butte OLDMAN ER Bow Island Taber Coaldale CR SOUTH SASKATCHEWAN OWS LETHBRIDGE NEST R. RIVER SUB-BASIN R.

RIVER RIVER STLE A Y C R. ON BELL

MARY MILK RIVER

WATERT ST. Montana

Seepage test sites

Figure 9. Seepage test sites.

36 c) Canal and Reservoir Evaporation Although usually a small component of conveyance losses in a distribution system, canal evaporation was accounted for in modelling the irrigation districts. Evaporation from large storage reservoirs can be significant and was also considered. A review of various methodologies was carried out to determine an appropriate approach for computing evaporation losses from canals and reservoirs. The irrigation districts have established nine weather stations and 34 rain gauges to supplement the existing agro-meteorological network. Data from these stations were standardized and converted to a format that could be used in the model. d) Irrigation Return Flow Return flow from irrigation districts is a major consideration in the quest to make additional water available for expanding the irrigated area within districts. Additional return flow data were required to gain a better understanding of the amount of return flow from the districts, its variability, its components and cause and effect relationships. The information was required to calibrate the IDM and to determine the extent to which reductions in return flow are possible. Five irrigation districts (BRID, EID, LNID, SMRID and TID) established 15 inflow and 87 return flow stations to provide data for return flow analyses (Figure 10). Additional information was collected in the irrigation block monitoring programs. MPE Engineering Ltd., Lethbridge, was retained to develop standards for data collection, storage and handling, to maintain quality control, and to ensure the data were in a form that could be readily used in modelling (MPE Engineering Ltd. 1997). The impacts of rainfall on return flow were reviewed to determine their significance and to assess the validity of algorithms used in the model.

3. Modelling Working Group The objective of the Modelling Working Group was to develop and calibrate computer models that could be used to reliably simulate a range of water supply and demand conditions. The simulations were required to test a variety of crop type and on-farm water management scenarios and district operational strategies. The model output will assist government and irrigation district decision-makers to make informed decisions related to long-term planning and development, as well as in their day-to-day operations. The implications of various levels of irrigation expansion, within the constraints of existing district licences and reservations, were explored. Computer simulation modelling of water demand and supply is an essential analytical technique for assessing water management options and optimizing the performance of complex water management systems. In the Irrigation Water Management Study, simulation models were used to compute water demands, water deliveries required to meet those demands, stream flows, canal flows, losses and reservoir levels for various scenarios of development, management options and operational policies. The models developed were sufficiently flexible that they could be used for both long-term planning and day-to-day operational purposes.

37 N RED DEER

RIVER

DEER RED DEER RIVER BASIN

RED

ROSEBUD Drumheller K R E E E D R British Columbia RIVER DEER C Saskatchewan Y

RIVER

BERR

RIVER Strathmore

ELBOWCALGARY BOW RIVER BOW RIVER BASIN RIVER Brooks

D A O RIVER O W

W E H LITTLE IG H H C T

BOW K S

SA RIVER WILLOW MEDICINE SOUTH HAT OLDMAN OLDMAN RIVER Vauxhall CREEK BASIN Picture RIVER RIVER Butte OLDMAN Bow Island Taber Coaldale CROWSNEST LETHBRIDGE SOUTH SASKATCHEWAN R. RIVER SUB-BASIN R.

RIVER RIVER

CASTLE R. ON BELLY Y

M M ER ILK RIV

WATERT ST. Montana

Instrument recording site Manually-read gauging site

Figure 10. Return flow monitoring stations.

38 Simulation modelling for planning purposes was conducted over a historical period of stream flow and climatic conditions. The output (water deliveries to meet demands, stream flows, reservoir levels, canal flows) represented what probably would have occurred if the management scenario had been in place during the period simulated. The simulation period was long enough, and comprised representative sequences of high and low stream flow and demand conditions, so statistical analyses of the model output could assess the performance of the system, the benefits of the scenario being tested, and its social and environmental impacts. The amount of water that Alberta can consume or store from the South Saskatchewan River system is limited by terms of the Prairie Provinces Water Board Master Agreement on Apportionment. In general, this agreement stipulates that Alberta must allow at least one half of the natural flow of the South Saskatchewan River, which includes the Red Deer, Bow and Oldman Rivers, to flow into Saskatchewan each year. Because of the apportionment commitments, water management and planning in the Red Deer, Bow and Oldman River basins are inextricably linked. Development in any of the three basins can affect existing or future development in the other two basins. In assessing management options where water supply is an issue, it is essential that simulation modelling include the entire SSRB. The SSRB is large and some parts of the basin are intensively developed. Water management is facilitated through a complex system of physical works, legal and institutional arrangements, operational procedures and constraints. The size of the basin and the complexity of its water management are such that it cannot yet be simulated using one, all-inclusive computer model. A nesting approach has been taken, whereby some parts of the basin are modelled separately from others. Smaller, more detailed models feed into larger models. For each scenario simulated, this approach may require two or more iterations before the analyst is assured the objectives of the model run are met to the utmost degree possible. Models that were developed (or refined) and used in a nesting approach in this study are the Irrigation District Model (IDM), which includes the Irrigation Requirements Module and the Network Management Module; the Water Resource Management Model (WRMM); and the Farm Financial Impact Risk Model (FFIRM). FFIRM was discussed earlier. The IDM and the WRMM are discussed below. a) Irrigation District Model (IDM) An irrigation requirements model was initially developed by Alberta Environment primarily to generate irrigation demands for use in the Water Resources Management Model (WRMM). In late 1994, the model was turned over to AAFRD for further development and support. Phoenix Engineering Inc. was retained to thoroughly review the model logic, and make it more flexible and user friendly. A specific objective was to make the IDM a useful decision support tool for both day-to-day operations and long-term planning. The IDM is comprised of two integrated modules. The Irrigation Requirements Module contains meteorological and field-based data needed to determine farm delivery requirements. The Network Management Module represents the physical characteristics of each district, including pipelines, canals, reservoirs and return flow channels, and their respective operating characteristics and losses. The Network Management Module combines the demands from the Irrigation Requirements Module, and converts them into the canal flows and diversions required to meet the demands.

39 The task of the Modelling Working Group was to review all aspects of the modules to ensure they were technically sound, flexible, user friendly and properly interfaced so they could be conveniently used with other models. A major task carried out to support the Irrigation Requirements Module was a detailed inventory of all on-farm irrigation systems and associated crop types. An interface program was developed to ensure irrigation districts' staff compiled data for every system and crop type within their respective districts in a model- compatible format. Pilot trials using software from various districts led to several modifications and enhancements. The final product is a powerful database that will serve a variety of needs within the irrigation districts. In addition, all irrigation districts and AAFRD committed considerable staff resources to develop an updated database on infrastructure locations and characteristics within the districts. A standardized GIS (Geographic Information System) format was used for the database. The IDM can tap this database for use in the Network Management Module. b) Water Resources Management Model (WRMM) The WRMM has been used extensively over the past 15 years, primarily by Alberta Environment, as the key analytical tool to assist in developing long-term plans, as well as to address current water management issues in the SSRB. The model has continuously been updated and improved. The WRMM (and its sub- models) models the entire SSRB, including all major storage reservoirs, diversions, water uses and apportionment commitments. Licence priorities are modelled for major water allocations. The model operates on a weekly time step for the historical period of stream flow and climatic conditions from 1928 to 1995. It will be used extensively in the province's SSRB water management planning process led by AENV. Because of the number of scenarios simulated with the IDM and the WRMM, the Modelling Working Group made every effort to ensure the configurations and operating modes of the two models were compatible, and the interfaces were completely seamless.

D. SIMULATION MODELLING The Irrigation Water Management Study included simulation modelling to determine the following. ! The significance of changes in crop mixes, on-farm management improvements and irrigation equipment, and future related trends. ! The significance of improvements in the distribution system and district water management, and related trends. ! The frequency and magnitude of water shortages and their impacts on producers at various levels of irrigation expansion, considering existing irrigation district licence amounts and reservations. Modelling conducted in this study is integrated with that conducted in AENV's SSRB water management planning process.

40 Simulation modelling in this study used the following assumptions. ! The rights and priorities of existing licences and licence-holders were recognized and adhered to. ! Alberta's interprovincial apportionment commitments were respected. ! Allowance was made for future municipal and industrial water demands. ! All established instream flow objectives were considered. ! Private irrigation demands included the existing licensed area and reservations for new irrigation blocks as defined in the 1991 South Saskatchewan Basin Water Allocation Regulation. ! No new provincial flow regulation works were considered beyond the existing and committed works. Each planning scenario consisted of basic criteria, which included crop mix, on-farm equipment mix, on-farm management capability, distribution system efficiency, and irrigated area within the districts. The modelling tools were applied in a cycle comprised of the following steps (Figure 11). ! The ideal irrigation demands were generated by the Irrigation Requirements Module. ! The ideal water delivery requirement was generated at main delivery points by the Network Management Module. ! The ideal water delivery requirement was input into the WRMM to determine if the requirement could be met, considering the hydrology, water demands, priorities, flow regulation capabilities and apportionment commitments in the SSRB. The WRMM output identified the frequency and magnitude of deficits in delivery of the ideal requirements. ! The deficits were input to the FFIRM to determine their financial impact. Phoenix Engineering Inc. and AAFRD staff conducted the IDM and FFIRM runs. AENV staff conducted the WRMM runs.

Acceptable Run

Irrigation Requirements Unacceptable -Modify Module Farm Parameters Impacts Irrigation Requirements

IDM IRRIGATION DISTRICT FARM FINANCIAL MODEL FFIRM Network IMPACT & RISK Management MODEL Deficits Module

Optimal Conditions WATER 1. Diversion Requirements -Minimized 2. Modified Diversion Deficits RESOURCES Requirements WRMM MANAGEMENT MODEL

Figure 11. Inter-relationships among IDM, WRMM and FFIRM.

41 E. LIMITATIONS OF THE IRRIGATION WATER MANAGEMENT STUDY The Irrigation Water Management Study focused primarily on irrigation within the 13 districts of southern Alberta. There are a number of peripheral or related issues that were not addressed. Following is a discussion of five such issues. 1. Private Irrigation There are more than 2,500 private irrigation projects in Alberta, about 80% of which are in the South Saskatchewan River Basin (Figure 12). The rate of growth of private irrigation has followed a pattern similar to that of the districts, with very rapid expansion in the 1970s and early 1980s, attributed largely to advances in sprinkler irrigation technology (Figure 13).

N RED DEER

RIVER

DEER RED DEER RIVER BASIN D E R

ROSEBUD Drumheller RED

British Columbia RIVER DEER CREEK Saskatchewan

RIVER

BERRY

R IVE R Strathmore

ELBOWCALGARY BOW RIVER BOW RIVER BASIN RIVER Brooks

N RIVER A

EW L IT H HIGHWOOD T L TC E

B O W SASKA RIVER WILLOW MEDICINE SOUTH HAT O L OLDMAN RIVER Vauxhall D C M R A E BASIN N E K Picture RIVER RIVER Butte OLDMAN Bow Island Taber Coaldale CROWSNEST LETHBRIDGE SOUTH SASKATCHEWAN R. RIVER SUB-BASIN

R. R E IV RIVER R

Licensed Irrigated Area CASTLE R. ON BELLY Y (1000’s of hectares) R MAR MILK E RIV

120 WATERT ST.

100 Montana

80 Irrigation districts

60 Private Irrigation

40 Figure 12. Private irrigation projects in the SSRB. 20

0 1890 1910 1930 1950 1970 1990 Year Figure 13. Growth of private irrigation in Alberta.

42 Since 1991, private irrigation expansion has been controlled by the South Saskatchewan Basin Water Allocation Regulation. The licensing authorities consider projects only in areas and up to limits defined in theRegulation . Water has been specifically reserved for 10 named projects in the basin (Table 5). Some of these projects may eventually become irrigation districts, or may be absorbed into existing districts. While the Irrigation Water Management Study did not analyse the characteristics and prospects for private irrigation, information generated in the study helped to define crop types, water uses and efficiencies for private projects. The potential evapotranspiration, growing season precipitation and moisture deficit maps are directly relevant to private projects, as well as district irrigation. All licensed private projects and all named projects in the South Saskatchewan Basin Water Allocation Regulation are included in simulation modelling. Variable water demands for licensed and future projects were estimated by AAFRD, based on the agro-climatic database and regional crop mixes.

Table 5. Private irrigation projects identified in the SSRB Water AllocationRegulation .

Project 1 Project Basin / Name Current Status (size in hectares) Size (ha) Red Deer River Basin Regulation Limit for Private Projects 39,256 Licensed Private Projects 1 13,881 Special Areas Water Supply Project 10,118 Feasibility studies underway.

Bow River Basin Regulation Limit for Private Projects 38,447 Licensed Private Projects 1 15,540 Siksika Nation 6,070 Feasibility confirmed. Discussions underway. Little Bow / Clear Lake 8,094 Storage reservoir under construction. Keho / Barons North 4,047 Inactive.

Oldman River Basin Regulation Limit for Private Projects 61,514 Licensed Private Projects 2 37,354 Blood Indian Reserve 10,118 Licensed: 10,118 Developed: 8,094 Peigan Indian Reserve 6,070 Under negotiation with Province. Keho / Barons South 4,047 Feasibility confirmed. To become part of LNID. Western Oldman Water Users 2,428 Individual projects. Licensed : 985 Oldman River Reservoir Area 6,070 Individual projects. Licensed: 1,025 Willow Creek 5,261 Reservoir filling underway. Licensed: 87

South Saskatchewan River Sub-basin Regulation Limit for Private Projects 21,044 Licensed Private Projects 19,507

South Saskatchewan River Basin Total 62,323 Regulation Limit for Private Projects 160,261 1, 2 Licensed Private Projects 86,282

1 Current licensed area based on March, 2000 records, Alberta Environment. Licensed areas may change daily. 2 Includes licensed area within Western Oldman and Oldman River Reservoir named projects.

43 2. Non-irrigation Uses in the South Saskatchewan River Basin The Irrigation Water Management Study does not address future non- irrigation uses in the SSRB. These uses will be addressed in AENV's SSRB water management planning process. AAFRD, working with AENV, conducted simulation modelling to test various scenarios of water use within the irrigation districts. For purposes of this modelling, an "allowance" was made for future non-irrigation uses. Instream flow needs in the SSRB were included, based on the best information available to AENV at the time of the modelling. This is not intended to preclude modelling that will be required during the course of AENV's planning process. Nor is it intended to circumvent AENV's responsibility for decision making nor to fetter its ultimate decisions. The allowances for non-irrigation uses may be modified during the course of AENV's planning and associated public consultation process.

3. Non-irrigation Uses through the Works of the Irrigation Districts In addition to providing water to irrigation water users, the districts' systems of canals, pipelines and reservoirs are used to provide water for a variety of other purposes. For instance, the SRMID has 495 domestic users (including 5 water co-ops and 3 grazing associations), 37 industrial users, and 12 municipal users that are supplied water through district works. The BRID supplies water to 43 non-irrigation licensees, (including 7 municipal, 17 stock water, 2 water co-op, 4 industrial, 8 water fowl conservation, and 5 recreation licences). The total licensed quantity for the non-irrigation projects within the BRID is about 4,070 cubic decametres, or less than 1% of the district's licensed volume. Non-irrigation withdrawal uses through the works of the districts require a licence under the Water Act (formerly the Water Resources Act), and an agreement between the licensee and the district. The licenced volume authorizes a diversion from the source that is in addition to the volume licensed to the district. The total licensed volume for non-irrigation uses in the 13 districts represents a small percentage of the total volume licensed for irrigation. However, it is significant that supplying water to many of these users requires special operating procedures and results in water losses and return flows that would not otherwise be experienced. The impacts of supplying non-irrigation uses on the districts' operations and water use efficiencies have not been quantified. Non-withdrawal uses are usually not licensed. A study by Alberta Environment (AENV 1989) determined there are more than 70 recreation sites on reservoirs that were constructed primarily for irrigation purposes. Several reservoirs are being used for commercial fishing (Lake Newell, McGregor Lake, and others). There are numerous wildlife conservation projects that rely on irrigation infrastructure for their water supply – some of these are licensed, others are not. While these non-withdrawal projects generally do not have a licensed allocation, their existence affects how the reservoirs are operated, and may affect district water losses and return flows. It is difficult to determine the total impacts of non-irrigation uses on district operations, water losses and return flows. These impacts have essentially been ignored in the simulation modelling and in determining the efficiencies of irrigation water use.

44 The relatively small quantity licensed to non-irrigation users belies the significance of the irrigation infrastructure in providing water for these uses, as well as the non-withdrawal uses. The irrigation infrastructure allows industries to locate where they might not otherwise locate, improves the distribution of stock water, permits better use of grazing lands, secures good quality water supplies for communities, provides recreational opportunities that otherwise would not exist, and secures water supplies for wildlife projects.

4. Water Management Headworks Losses By the early 1970s, the main supply works that conveyed water from the source streams to the irrigation districts were in a serious state of disrepair. Rehabilitation of these works was beyond the fiscal capabilities of most districts. In 1975, AENV committed to take over all major onstream headworks and to assume responsibility for operation, maintenance and rehabilitation. The Province's objective was to operate these works "to maintain a secure and continuous supply of water" for multi-purpose use. AENV negotiated takeover agreements with all districts except the EID and UID. Negotiations with the UID are continuing. The headworks are comprised of about 330 km of canals, three onstream storage reservoirs and eight offstream storage reservoirs. These works have seepage and evaporation losses. In the Irrigation Water Management Study, these losses are not included in analysis of the irrigation district water demands and efficiencies for the following reasons. ! The headworks are intended for multi-purpose use, not solely for irrigation. ! The headworks licences issued to AENV for the Lethbridge Northern Headworks, the Waterton-St.Mary Headworks and the Oldman River Dam include relevant losses. ! The licences issued to the irrigation districts (with one exception) and the 1991 Regulation licence volumes were based on crop water requirements, losses due to district works, and return flows. Headworks losses were not included. The only irrigation district licence that includes headworks losses is that issued to the BRID in 1982. Headworks losses must be considered in evaluating the water supply potential of the source streams and assessing the risks of irrigation expansion. Losses are, therefore, included in all simulation model runs conducted by AENV.

5. Climate Variability The performance of the water supply system during droughts, such as those sometimes experienced in the SSRB, is a key factor in determining irrigation expansion potential. The characteristics and impacts of such droughts on large water management systems are often addressed through simulation modelling, using a recorded period of streamflow and weather conditions. The approach infers that the performance of the system during a lengthy period of recorded conditions provides insight into how well the system might perform in the future. However, three significant issues must be considered in interpreting the results of simulation modelling based on historical records of streamflow and weather conditions in the SSRB.

45 a) Historic Climate Variability How well does the 68-year period of recorded conditions represent the variability in water supply and demand that can be expected in the future? Studies of tree rings, lake sediments and other indicators on the Canadian prairies have shed some light on the climate of past centuries. From a review of available information, Sauchyn (1997) concluded that, ".... the recent occupants of the Palliser triangle have not yet experienced the extremes of summer precipitation that occurred in the 19th and late-18th centuries, and that could reoccur in the near future." This conclusion suggests modelling results using the recorded period could present an overly optimistic picture of long-term water supply and demand. b) The 2001 Experience in the Oldman River Basin The 68-year simulation period (1928 to 1995) does not replicate the extensive impacts of a combination of limited water supplies and high demands such as experienced in the Oldman Basin in 2000 and 2001. Preliminary analyses of water demand and natural water supply indicate that such a combination of conditions were unprecedented in the simulation period. The deficits were exacerbated by drawdown of the St. Mary Reservoir to facilitate construction of a new spillway. c) Future Climate Variability How will future climate variability affect the performance of the water management system in the South Saskatchewan River Basin? Several researchers have concluded there is insufficient information to develop and analyse a credible climate change scenario at a regional level (Klemes 1990 and 1991; Muzik 2001; Filion 2000). However, the possibility that future weather and streamflow may be different than in the past must be recognised. Flexibility should be designed into management decisions and the operation of the infrastructure to allow for mitigation of negative impacts and to take advantage of positive impacts of climate change.

46 IV.

Chapter Key Research Findings Chapter IV. Key Research Findings

Following is a summary of key findings of the research projects of the Irrigation Water Management Study, and the extensions of those research findings. The results help define the current status of the 13 irrigation districts and the irrigation industry in Alberta, and their prospects for the future. Where possible, comparisons were made between these study findings and the assumptions made in 1991 to determine theRegulation licence volumes (Table 4). These comparisons were made to give an appreciation of why the irrigation districts may (or may not) expand their irrigated area from that specified in the 1991Regulation within the constraints of the proposed licence volumes. A distinction is made between on-farm components (irrigation methods, management practices, etc.) and district componentssuch as seepage and evaporation (Figure 14). The research findings indicated areas where improvements could be made, by whom, and the likely impacts of the improvements. This serves to focus the attention of farmers and irrigation district managers on issues they can influence, and those that will provide the best outcomes for the effort and resources invested.

Non-irrigation Uses -recreation -municipal Canal & Reservoir -industrial 6% Evaporation -stock watering 4% -wetlands Stored Soil 47% Moisture Farm Farm Losses Deliveries - evaporation -lost runoff Canal Secondary Canal Canal Main Canal 17%-deep percolation Gross Diversion Seepage 100% 3% Canal Base Flow Recaptured Operational Spills Runoff 6% Down-time flowby 2% 15% River Tributary Major Return Drain Flow

NOTE: Percentages vary from year to year and from district to district. Percentages shown are typical.

Figure 14. Components of the irrigation district gross diversion demand.

49 A. ON-FARM COMPONENT On-farm factors that affect irrigation water requirements and irrigation application efficiencies are climatic conditions, crop types, irrigation methods, and on-farm management practices.

1. Agro-climatic Database AAFRD has supplemented existing geographic agro-climatic information by computing and incorporating parameters that are of particular interest to the irrigation community. Maps showing the variations in potential evapotranspiration, growing season precipitation and net moisture deficit across the SSRB were developed. Although data gaps exist, in general the Gridded Prairie Climate Database (GRIPCD) provides daily values at 50-km grid points for the following parameters and periods: , Maximum and minimum air temperatures – 1920 to 1995; , Solar radiation – 1951 to 1995; Potential evapotransporation , Dew point temperature – 1955 to 1995; refers to the maximum , Rainfall – 1920 to 1995; transfer of water from the soil , Snowfall – 1920 to 1995; to the atmosphere, due to evaporation from the soil , Precipitation – 1920 to 1995; and surface and transpiration , Snow depth – 1956 to 1995. from plants, and assuming a To complement theGRIPCD , additional parameters, such as potential continuously moist soil evapotranspiration, growing season precipitation, net growing season moisture profile. deficit, corn heat units and frost-free days were computed for the period 1920 to 1995. Of particular interest in this study are potential evapotranspiration, growing season precipitation andnet growing season moisture deficit . Potential evapotranspiration is a key parameter on which most assessments of irrigation water requirements are based. Five equations for the computation of potential evapotranspiration were reviewed and evaluated. A modified Priestly- Taylor equation provided the best correlation with research data published by Agriculture and Agri-Food Canada and was selected for the computations. The Priestley-Taylor equation is based on maximum and minimum temperatures and solar radiation. Solar radiation data have been recorded in southern Alberta only since 1950, and these records have significant data gaps. Solar radiation was estimated by AAFRD based on maximum and minimum temperatures, latitude, and elevation, to provide daily data for the 76-year period 1920 to 1995. Daily potential evapotranspiration values for the full period were computed for each of the grid points. Potential evapotranspiration values represent the evapotranspiration for the lush green growth of a high water use crop, such as alfalfa. Evapotranspiration for alfalfa and other crop types can be computed by multiplying the potential evapotranspiration value by a crop coefficient. Coefficients for various crop types have been developed by Agriculture and Agri- Food Canada (Foroud and Hobbs 1983). Growing season precipitation is natural moisture that is provided to the soil profile to support plant growth. The growing season was taken to be the period between the last killing frost day in the spring and the first killing frost day in the fall. A killing frost day is defined as a day in which the minimum temperature was less than –2.0 degrees C. The net growing season moisture deficit is the difference between evapotranspiration and growing season precipitation. It represents the irrigation requirement for the optimum yield of a high water use crop such as alfalfa.

50 The design of irrigation district infrastructure and on-farm systems is normally based on irrigation requirements during hot, dry periods. The objective is to ensure there will be sufficient capacity in the system to meet demands when irrigation is most needed and most beneficial. For this reason, crop water requirements during extreme conditions were of primary interest. The volumes of water licensed or proposed to be licensed to the irrigation districts were also based on the 90th percentile irrigation requirements, the water requirements that would be expected to be exceeded in only 10% of the years. Maps have been prepared showing the 90th percentile evapotranspiration (Figure 15), the 10th percentile growing season precipitation (Figure 16), and the 90th percentile net growing season moisture deficit (Figure 17). These maps provide indices showing the variations in crop water requirements and irrigation demands for a high water demand crop and hot, dry conditions in the SSRB. In general, growing season precipitation decreases from west to east, and potential evapotranspiration andnet growing season moisture deficit increase from west to east. Thenet growing season moisture deficit is about 100 mm higher in the Medicine Hat area than in the Cardston, Fort Macleod, and Strathmore areas. The gridded database was the source of all weather data for determining crop specific water demands, soil moisture balances and evaporation losses in the Irrigation District Model (IDM). The database was also used to assess the impacts of irrigation water shortages on crop yields in the Farm Financial Impact and Risk Model (FFIRM). AAFRD has used the database to develop an index of agro-climatic factors that will assist in the design of on-farm irrigation equipment for specific crop types and regional climatic conditions. The crop mix in the irrigation districts has changed during 2. Crop Types and Water Requirements the past 30 years. The area There are several agronomic factors that influence crop growth and yields. A planted to forage, specialty key factor is the availability of soil moisture. (Other factors include soil fertility, and oilseed crops has diseases and pests.) While giving due consideration to these other factors, increased, and the area of providing adequate soil moisture for high crop yields is the essence of irrigation cereal crops has decreased. It water management. Irrigation planning and management requires that crop water is expected this trend will requirements for optimum yields be known and factored into the design and continue in the future. In spite operation of the irrigation system. of this change in crop mix, there will probably not be a A wide variety of crops is grown on irrigated land in southern Alberta. significant change in the However, much of the crop water use information commonly used today is based overall crop water on decades of field monitoring and research conducted more than 30 years ago. requirements for the districts. In 1998 and 1999, research was conducted on alfalfa to determine if new varieties and irrigation management techniques have significant effects on irrigation water use. Randomized, replicated research plots were located near Picture Butte, Rolling Hills and Bow Island (Olson et al. 2000). Five irrigation management strategies or treatments were tested. 50-100 Non-stress Treatment: Irrigate to maintain available soil moisture (ASM), including precipitation, at 50% to 100% of field capacity. 50-80 Non-stress Treatment: Irrigate to maintain ASM at 50% to 80% of field capacity. 30-60 Stress Treatment: Irrigate to maintain ASM at 30% to 60% of field capacity. Volume-Restricted Treatment: Maximum irrigation application of 275 mm. Date-Restricted Treatment: Cut off irrigation on June 30.

51 N

RED DEER 750 760 780 RIVER 800 DEER RED DEER RIVER BASIN D E R

700 720 ROSEBUD Drumheller 820 RED 640 680 740 EEK

600 CR Saskatchewan British Columbia 660 RIVER DEER 620 RIVER

BERRY 840 RIVER Strathmore

ELBOWCALGARY BOW RIVER BOW RIVER BASIN RIVER 840Brooks N RIVER A OOD W

E LITTLE

HIGHW 860 CH T

BOW SK

700 720 SA 680 740 840 760 780 R WILLOW 800 IV E MEDICINE R 820 SOUTH HAT OLDMAN OLDMAN RIVER Vauxhall C RE BASIN E K Picture RIVER RIVER Butte OLDMAN Bow Island Taber Coaldale CROWSNEST LETHBRIDGE SOUTH SASKATCHEWAN R. RIVER SUB-BASIN R.

860 880 RIVER RIVER Y CASTLE R. ON BELL 900 MARY M ILK RIVER

WATERT ST. Montana

Figure 15. Potential evapotranspiration in the South Saskatchewan River Basin. (90th percentile values for the killing frost-free period, in mm)

52 200

190

N 180 170 RED DEER

RIVER

DEER RED DEER RIVER BASIN150 160 D E R 160 150 150 ROSEBUD Drumheller 170 RED EEK British Columbia 180 RIVER DEER CR Saskatchewan 140 RIVER

BERRY 130 110 140 120 140 RIVER Strathmore

ELBOW 130 CALGARY BOW RIVER BOW RIVER BASIN RIVER Brooks

N RIVER A OOD W

E LITTLE

HIGHW CH T

BOW SK

SA R WILLOW IV E MEDICINE R SOUTH HAT OLDMAN OLDMAN RIVER Vauxhall C 140 RE BASIN E K Picture RIVER RIVER Butte OLDMAN Bow Island 130 Taber Coaldale CROWSNEST SOUTH SASKATCHEWAN R. 140LETHBRIDGE RIVER SUB-BASIN 130 R. 150 120

RIVER RIVER 160 Y CASTLE 140 R. ON BELL

MARY M ILK RIVER

WATERT ST. Montana

Figure 16. Growing season precipitation in the South Saskatchewan River Basin. (10th percentile value for the killing frost-free period, in mm)

53 N 400

560 RED DEER 520 580 540 600 420 620 440 RIVER 460 DEER480 RED DEER RIVER BASIN 640 D E R 500

ROSEBUD Drumheller 660 RED

REEK

RIVER C Saskatchewan British Columbia 520 DEER RIVER

BERRY 500 680 RIVER 480 Strathmore

ELBOWCALGARY 700 BOW RIVER BOW RIVER BASIN RIVER Brooks

N RIVER A OOD 500 W E 520 LITTLE 540 H C HIGHW 560 580 T 600

620 BOW KA

SAS 640 R WILLO IV W E MEDICINE R SOUTH HAT OLDMAN OLDMAN RIVER Vauxhall 720 C R EE BASIN K Picture RIVER RIVER Butte OLDMAN Bow Island Taber

Coaldale CROWSNEST SOUTH700 SASKATCHEWAN LETHBRIDGE 680 R. RIVER SUB-BASIN 660 R. 740

RIVER RIVER Y 760 CASTLE R. ON BELL

MARY M ILK RIVER

WATERT ST. Montana

Figure 17. Net growing season moisture deficit in the South Saskatchewan River Basin. (90th percentile value of the annual difference between potential evapotranspiration and precipitation for the frost-free period, in mm.)

54 All plots were treated equally in the establishment year. Following the establishment year, all five treatments were applied to the four plots at three sites (Figure 18). Water use and yields were monitored for all plots and all treatments. Differences that were statistically significant at a 5% level of probability were noted. There were no significant differences in crop consumptive use between the two non-stress treatments. The non-stressconsumptive use ranged from 530 mm to 601 mm for four of the five treatments. For research conducted in the 1960s, Sonmor (1963) and Krogman and Hobbs (1966) reportedconsumptive use for alfalfa ranging from 660 mm to 680 mm. Preliminaryconsumptive use values from current research are significantly lower than those of the 1960s. Additional results are necessary to determine the reasons for the difference (alfalfa varieties used, research methods, irrigation techniques, etc.). Consumptive use and yields over a variety of weather conditions should also be monitored before any definitive conclusions can be drawn. Research is continuing. Based on results to date, n o change in past procedures for determining crop water requirements is warranted. The non-stressconsumptive use for the Bow Island crop was substantially lower than for crops at other sites, with no yield reduction. The Bow Island site has a shallow water table that is probably a non-monitored contributor to crop water needs. Consumptive use for the 30-60 Treatments was significantly less than the 50-100 Treatments in only two of the five crops – Rolling Hills 1, 1998, and Rolling Hills 1, 1999. The consumptive use for the Volume-Restricted Treatments was significantly less in two of the five crops – Rolling Hills 1, 1998, and Picture Butte 1, 1999. The consumptive use for the Date-Restricted Treatments was significantly less in all crops except Bow Island, 1999. Total yield for all treatments at all sites (Figure 19) was measured from three cuts, except at Rolling Hills 1 site, 1998, where four cuts were obtained. There was a tendency for yields to decrease with each successive cut at all sites. Annual yields for the 50 - 100, 50 - 80 and 30 - 60 Treatments were similar and tended to be the

600 Treatments 50 - 100 400 50-80 200 30-60 275 mm 0 Rolling Hills 1 Rolling Hills 1 Rolling Hills 2 Picture Butte 1 Bow Island 30-Jun

Consumptive Use (mm) 1998 1999 1999 1999 1999 Figure 18. Alfalfa project consumptive water use.

Treatments 15 50 - 100 10 50-80

Yield (mg/ha) 5 30-60 275 mm 0 Rolling Hills 1 Rolling Hills 1 Rolling Hills 2 Picture Butte 1 Bow Island 30-Jun

Dry Matter 1998 1999 1999 1999 1999 Figure 19. Alfalfa project yields.

55 8

6 Alfalfa Sugar Beets Soft Wheat 4 Beans Barley 2

Evapotranpiration (mm/day)

0 May June July Aug. Sept. Figure 20. Monthly mean water demand for optimum yields of selected crops. highest at each site. The yields from the Volume-Restricted Treatment tended to be less. However, they were significantly less than the 50-100 Treatment yields only at Rolling Hills 1, 1998, and Picture Butte 1, 1999. The Date-Restricted Treatments had the greatest impact on yields. Significant reductions were observed for all crops except at Bow Island, 1999. Water use patterns have been monitored by researchers for several decades, beginning in the 1960s. The timing and total crop water requirements for optimum yields for various crops differ substantially (Figure 20). For most crops, the peak moisture use occurs in July, which is a key consideration in the design and operation of irrigation projects. On-farm systems, main canals and laterals may be operating at their full design capacities during the month of July. The peak water requirement for sugar beets is later than most other crops, which helps to distribute the demand in an irrigation block with a mix of crop types. Alfalfa has the highest water requirements in all months. In some months, the water requirement for alfalfa is more than double the requirement for other crops. The crop mix within an irrigation block has a significant bearing on the irrigation water requirement for the block. In 1998, more than 50 different crops were grown in the irrigation districts of southern Alberta. Crops have been grouped into seven categories for the purpose of characterizing water use. Representative crop types and their water requirements are shown in Table 6.

Table 6. Irrigated crop water requirements. Typical Crop Max. Daily Total Seasonal Growing Crop Category Type Water Use1 Water Use1 Season (mm) (mm) (Days) Cereal– LoCU2 Malt Barley 7.2 390 85 Cereal– HiCU Soft Wheat 7.4 480 115 Forage– L oCU Barley Silage 7.2 370 70 Forage– HiCU Alfalfa 7.6 680 140 Oilseed Canola 7.7 450 110 Specialty– LoCU Field Beans 5.7 380 105 Specialty– HiCU Sugar Beets 6.0 560 135 1290th percentile requirements. CU= consumptive use.

56 The crop mix categories grown within the irrigation districts in 1999 are shown in Table 7. In general, districts in the western part of the basin, with higher elevations and cooler, moister climatic characteristics, are dominated by cereal and forage crops. These crop types complement the livestock-based farm enterprises in that part of the basin. In districts located farther east, where temperatures are higher and the growing season is longer, the crop types are markedly more diverse (Figures 21, 22, 23). During the 1970s, agricultural policy in Alberta focused on increasing both dryland and irrigated crop production through increasing the cropped area. During this period, the irrigated area within the districts experienced unprecedented growth (Figure 4, page 16). During the 1980s, the emphasis on agriculture shifted to crop diversification and, specifically, growing a variety of higher value crops on irrigated lands. Generally, these crops were grown for the export market and shipped as unprocessed produce.

Table 7. Crop mix within the irrigation districts of southern Alberta - 1999.

Cereal Crops (%) Forages (%) Specialty Crops (%) Irrigation Oilseeds District LoCU1 HiCULoCU HiCU(%) LoCU HiCU

Aetna 19.30.0 11.5 68.1 1.1 0.0 0.0

Bow River 23.0 20.74.4 23.1 13.36.1 9.4

Eastern 25.04.68.6 43.8 8.0 2.9 7.1

Leavitt 12.57.538.3 41.2 0.0 0.0 0.0

Lethbridge Northern 19.96.640.9 15.9 7.4 1.0 8.3

Magrath 46.83.06.2 34.3 9.3 0.4 0.0

Mountain View 3.94.520.7 70.4 0.6 0.0 0.0

Raymond 35.20.711.8 42.5 9.7 0.0 0.1

Ross Creek 0.00.06.6 93.4 0.0 0.0 0.0

St. Mary River 23.616.77.7 21.0 12.4 10.4 8.2

Taber 14.813.19.8 23.6 3.1 13.1 22.6

United 44.52.716.5 29.7 6.3 0.2 0.1

Western 36.91.120.9 35.2 12.4 1.9 1.5

Weighted Mean 24.210.913.2 28.2 10.0 5.6 7.9

1CU = consumptive use.

57 #

# # # # #

# #

# # #

# #

# # # # #

# # # #

# # # # #

# # #

# # # #

# #

# # #

# #

# # #

# #

# # #

# #

# # # # #

# # # #

# #

# # #

# #

# # # #

# # # # # #

# # # # #

# # #

# # # # # # # #

# # # #

# # #

# # # # #

# # #

# # # #

# #

# # # # #

# # #

# # # # # # # # # # #

# # # #

# # #

# # # # # # # # # # # #

# #

# # # # #

# # # # # #

# # #

# # # # # #

# #

# # # # # # # # # # #

# # #

# # # #

# # #

# # # # # # #

# #

# # # #

# #

# # #

# #

# # # #

# # # # # # # # # # # # # #

# #

# # # #

# #

# # # # #

# # # # # # # #

# #

# # # #

# # # # # # # #

# # # # # # #

# #

# # #

# #

# # #

# #

# # #

# # # # # # # # # # # # # # # # #

# # # #

# # #

# # # # # # # #

# #

# # # # #

# #

# # # #

# #

# # # # # # # # # # #

# #

# # # # # # #

# # #

# #

Medicine Hat

# # #

# # # # # #

# #

# # # # #

# # #

# #

# # #

# # # # #

# #

# # #

# #

# # # #

# # #

# #

# # # # #

# #

# # # # #

# #

# # # # #

# #

# # # # # #

# #

# # # #

# #

# # # # #

# #

# # # # # #

# #

# # #

# #

# # #

# #

# # #

# #

# # #

# #

# # # # #

# # #

# #

# # #

# #

# # #

# #

# # # #

# #

# # #

# # # #

# #

# # #

# #

# # # # #

# # # # # # #

# # #

# #

# # #

# #

# # #

# # # # #

# #

# # # #

# # #

# # # # #

# #

# # # # #

# #

# # # # #

# # # # # #

# # #

# # # #

# #

# # # # # # #

# # #

# # # # # # # #

# #

# # #

# #

# # # # # #

# #

# # # # #

# # # # # #

# # #

# #

# # #

# # # # # # # # #

# # #

# # # # #

# #

# # # # ## # #

# #

# # # # #

# #

# # # # # # #

# # #

# # # # # #

# #

# # # # #

# # # #

# #

# # # # #

# # # # # #

# #

# # # #

# # #

# #

# # #

# #

# # # # #

# #

# # # # #

# #

# # # #

# #

# # #

# # # #

# #

# # # # # #

# # # # #

# # #

# #

# # # #

# # # # # #

# # # # #

# #

# # # #

# #

# # # # # # # #

# # # # # # # # #

# #

# # #

# # # #

# # # # #

# # # # # # # #

# # # #

# #

# # # #

Specialty crops Oil seed crops Forage crops Cereal crops

# #

# # # # # # #

# #

# # # # # # # # # #

# #

# # #

# # # # # # #

# # # #

# # # # # # # #

# # # # #

# # # # # #

# #

# # # #

# # # # # # # #

# # # #

# #

# # #

# # # #

# #

# # # # #

# # #

# # # # #

# #

# # # #

# #

# # # # # # #

# #

# # #

# #

# # # #

# # # # #

# # #

# # # # # #

# #

# # #

# # # #

# # # # #

# #

# # # #

# #

# # # # # #

# #

# # # #

# # # # # #

# # # #

# #

# # #

# #

# # # #

# #

# # # # # #

# #

# # # # #

# #

# # #

# #

# # #

# #

# # #

# # # #

# # #

# # # #

# #

# # #

# #

# # # #

# # #

# # # # #

# #

# # # # #

# # #

# # # #

# #

# # #

# # # #

# #

# # # #

# # #

# # # #

# #

# # # #

# #

# # #

# # # #

# #

# # # # #

# #

# # # # #

# # #

# #

# # # #

# #

# # #

# #

# # # # #

# #

# # # # #

# #

# # #

# # # # # #

# #

# # #

# # # # # #

# # #

# #

# # #

# #

# # #

# #

# # #

# # # # #

# #

# # #

# #

# # # # # # #

# # # # #

# #

# # #

# #

# # # # # #

# #

# # # # # # #

# #

# # # #

# #

# # #

# # # #

# #

# # #

# #

# # #

# # # # #

# #

# # #

# #

# # #

# #

# # # # # # #

# # # #

# # #

# #

# # # #

# #

# # #

# # # # # # #

# # # # # #

# #

# # # #

# #

# # # #

# # # # # # # #

# # #

# #

# # # # # #

# # # #

# # #

# #

# # # # # #

# #

# # #

# # # #

# #

# # #

# # # # #

# #

# # #

# #

# # #

# # # #

# # #

# #

# # # # #

# # # #

# # #

# # # # # # # # # # #

# #

# # #

# #

# # #

# # # #

# #

# # # # #

# # #

# #

# # # # #

# #

# # # # # #

# #

# # #

# #

# # #

# # # #

# #

# # # #

# #

# # # #

# # #

# # # # # # #

# # # # # #

# # # #

# # #

# # # #

# #

# # # # # # #

# # #

# # # #

# #

# # #

# # # # # #

# # # # #

# # # #

# # #

# #

# # #

# # # # #

# # #

# # # # # #

# # #

# #

# # #

# #

# # #

# #

# # #

# # # # #

# #

# # # #

# # # # #

# #

# # # #

# #

# # # # #

# # #

# #

# # # # #

# #

# # # #

# #

# # # #

# # # # # #

# #

# # #

# # # # # #

# #

# # #

# #

# # #

# # # #

# # #

# #

# # # # # #

# # #

# # # # #

# #

# # # # #

# # # #

# # #

# #

# # # #

# #

# # #

# #

# # #

# #

# # #

# #

# # #

# #

# # # #

# #

# # #

# #

# # #

# #

# # #

Taber

# #

# # #

# #

# # #

# # # #

# #

# # # # #

# #

# # #

# #

# # #

# #

# # #

op group distribution.

# # # #

# # #

# #

# # # #

# #

# # # # # # #

# # # #

# # # # #

# #

# # # #

# # #

# #

# # # #

# # #

# #

# # # #

# #

# # # # # #

# # #

# # # #

# #

# # #

# #

# # #

# # # # #

# #

# # # # # # #

# # #

# #

# # # #

# #

# # # # # #

# # # #

# # #

# # # #

# # # # # #

# #

# # # #

# #

# # # # #

# # #

# # # #

# # #

# #

# # #

# #

# # # #

# #

# # # #

# # # # #

# # #

# #

# # #

# #

# # # # #

# # #

# # # #

# #

# # # #

# #

# # # # # # #

# # #

# #

# # #

# # # # # #

# # #

# #

# # #

# #

# # # # #

# #

# # # # # #

# #

# # # #

# #

# # #

# #

# # # # # # #

# # # #

# # #

# #

# # # # #

# #

# # # # # #

# #

# # #

# # # #

# # #

# # # # # #

# #

# # # #

# # # # #

# #

# # #

# #

# # # #

# #

# # # # # #

# # #

# # # #

# #

# # #

# #

# # # # #

# # # # # # # #

# # #

# # # # #

# # #

# #

# # # #

# # #

# #

# # # #

# #

# # # #

# #

# # # # # #

# # #

# #

# # # #

# #

# # # # # #

# # # #

# #

# # # #

# #

# # # #

# #

# # # #

# # #

# #

# # # # # #

# #

# # #

# #

# # # # # # #

# # # #

# #

# # # # # #

# # #

# # # # # # # #

# # #

# #

# # # #

# # #

# #

# # # # #

# # #

# #

# # #

# #

# # # # #

# #

# # # # #

# #

# # # # # #

# # #

# #

# # # #

# # # # # # #

# #

# # #

# # # # # # #

# # #

# #

# # # # #

# # # #

# #

# # #

# # # # #

# # # # # #

# # #

# #

# # #

# #

# # #

# # # #

# #

# # #

# # # #

# # #

# #

# # # # # #

# #

# # #

# # # # #

# #

# # #

# # # # #

# #

# # #

# #

# # #

# # # #

# # #

# #

# # # # #

# # # #

# # # # # #

# #

# # # # # # # #

# #

# # #

# #

# # #

# # # # #

# #

# # #

# # # #

# #

# # # # #

# # #

# # # #

# #

# # # # #

# #

# # # #

# #

# # #

# # # # #

# #

# # # # # # #

# # #

# #

# # #

# #

# # # # #

# # # # # # #

# #

# # #

# #

# # #

# # # #

# # #

# #

# # # # #

# #

# # # # #

# # # #

# #

# # # #

# #

# # # # # # #

# #

# # # #

# #

# # # #

# #

# # # # # # # #

# # # # # #

# # #

# #

# # #

# #

# # #

# # # # # #

# #

# # # #

# # #

# #

# # #

# #

# # #

# #

# # #

# #

# # # #

# #

# # #

# # # #

# #

# # #

# #

# # #

# #

# # # #

# # # # # #

# # # # # # # #

# # # #

# #

# # # #

# # # # # #

# #

# # # # # # #

# # #

# #

# # # #

# #

# # # # #

# #

# # #

# #

# # # #

# #

# # #

# #

# # # #

# # #

# # # #

# #

# # #

# # # # # #

# # # #

# #

# # # # #

# # # # # # # # #

# #

# # #

# #

# # # #

# # #

# #

# # #

# # # # # # # # #

# #

# # # # # #

# #

# # #

# # # # # # # #

# #

# # #

# # # # #

# # #

# # # # # #

# # # # # # # #

# #

# # #

# #

# # #

# # # # # #

# # #

# # # #

# #

# # # # #

# # # #

# # #

# #

# # # # # #

# # # #

# # #

# #

# # #

# #

# # # # # #

# #

# # # # # #

# # # # # # #

# # # #

# #

# # # # # # # #

# #

# # # #

# # # # #

# # # # # # #

# # #

# # # #

# # # # # # #

# #

# # # # # # # #

# #

# # #

# # # # # # # #

# #

# # # # # # # #

# # # # #

# # #

# # # #

# # # # #

# # # #

# # # # # #

# #

# # # #

# #

# # # # #

# # #

# # # # #

# # # # # # # # # # #

# # # #

# # # # # #

# # #

# #

# # #

# #

# # # #

# # # # # #

# # #

# # # # #

# #

# # # # # # #

# #

# # # # #

# #

# # #

# # # # #

# # #

# #

# # # #

# # # # #

# #

# # #

# #

# # #

# #

# # # # #

# # #

# # # #

# # # # # #

# # # # #

# #

# # # # #

# #

# # #

# #

# # # #

# # # # # #

# #

# # #

# # # #

# #

# # #

# # # # # #

# #

# # #

# # # #

# # #

# # # # # #

# #

# # #

# #

# # #

# # # #

# # #

# # # # # # #

# #

# # # #

# # #

# #

# # # #

# #

# # #

# #

# # #

# #

# # # # #

# #

# # # # # #

# #

# # # # #

# # #

# #

# # # # # #

# #

# # # # # # #

# #

# # # # # # # # # #

# #

# # #

# #

# # #

# #

# # #

# #

# # # # # #

# #

# # #

# #

# # #

# #

# # #

# # # # # #

# # # # # # #

# #

# # # # # #

# # # # #

oject and LNID 1999 cr

# # #

# #

# # # # #

# #

# # # # # #

# # # #

# #

# # # #

# # #

# #

# # # #

# #

# # # # # #

# #

# # # # #

# #

# # #

# #

# # # # #

# #

# # # #

# #

# # #

# #

# # # # # # #

# #

# # # # #

# # # # # # #

# # # #

# # #

# # # # #

# # # #

# #

# # #

# # # #

# #

# # #

# #

# # #

# #

# # # # #

# # #

# # # #

# # #

# #

# # #

# #

# # # # #

# #

# # #

# #

# # # # # # # # #

# # #

# #

# # # #

# #

# # # #

# # #

# # # # #

# #

# # #

# #

# # #

# #

# # # # #

# #

# # #

# #

# # # # #

# #

# # # # #

# # #

# # # # #

# # #

# #

# # # # #

# # # #

# #

# # #

# #

# # #

# #

Lethbridge

# #

# # # #

# #

# # #

# #

# # #

# #

# # #

# #

# # #

# #

# # # #

# #

Figure 21. St. Mary Pr

# #

# # # #

# #

# # # #

# # #

# #

# # #

# #

58 # # # # # # # # # # # # # #### # # ## # # # ## # # ### # # # # # # # # # ## # # # # ## # # # # ## #### #### # # # # # ## # ## # # ### # ### ### # # # # ### # ### # ## # # ## ## ### # ## # ## # ## ## # # # # ### # # # # ## # # # # # #### # # # # # ## # ### # ### ### #### ##### ## # ## # ## ### ### # # # # # ### ###### # ## # #### # # ### # # # # # # # # ####### # ## # ## ##### # # # # # # # # # # ## # # # ### # # # ## # # # # ## ### # ## # # ## # # ## ## # # # # # # ### #### # # # # # # # ## # ## ### ## # ## # ## # # # ## # # ## ## # # ### ### # # # ### # ## #### # # # # ### ## # # # ### # # #### # #### ### # # ### # # # ## ## #### # # # ## ## ## # ### ##### ## # # ## # # # ### #### ####### # # # # # # # #### ## ## # # ## ## ## ### # # #### # ##### ## # # # ## # # ## ### # # #### ## ### # ## # ### # # #### # ######## ### ## # # # ## # ### ### # # # # ## ### # ### ### ###### # # # # # # # ### # ### ## ### # # # # # # # # ### ## ## # ## ## # ### ## ## ## # # ### # ###### # ### # # ## # # ## # # ### ### # # # # ### ## # # # # ##### ## ### # ## # ## # #### # ## ## # # # ### ### ## # # ## # #### ## # ## # # ###### #### # # # # ### # #### # # ### ##### #### ### # # # ### # ## # ## ### # # # # # ### # # # ### ## # ## # # ## # # # # # ## ## ###### #### ##### ## # # # # ####### ## # # ### # # # # # ## # ## ## # #### ###### # # # ##### # # #### # ## ### # # # ## ## ########## ## # #### # ## ## #### # # # # # # ## # #### ### # ## # # ### # # # # # # # ######## # # # ## # # ### ### # # ## ##### ## # # ### # # # ## # # # # #### ## ###### # # # #### # # ## ## # #### # # ### ######## # # # #### # ### # ## # ##### ### # # ## # # ### # # # ######## ## ### ### # # # ######### # # # # # # # ### #### # ## ### ## ## # ### ## ###### # ## ## # ## # # # ## ## ## ##### ##### #### # # # # ### # # # ## ## ########## ### # # ## ## # # # # ### #### # # # ## ### # # # # # ## # # ## # ###### # ## ## # # # # # # ## ### ## # ## ### # ## ## # # ## # # # ## # ### #### ## ## ### # # ## # # #### #### # #### ###### # # # # # # # ###### ### ## ## # ###### ## ######## # #### ##### ### ## ## ##### #### ######### # # # ### ### # # ##### ###### #### # ###### ##### ### Bassano ## # # ### ############ #### ###### ##### ## ## ##### ########## ## # ######## # # # ########## ############## ## # ##### # ## ## ### # ## # # ############# ##### # # # # # ### ######### ############### # #### ##### ### ### # ## ## # ### ### ##################### ### ### #### #### # # # # # ### ##### #### ############## ### # ###### # #### # # #### ## # ################## ##### ########## # # # ##### ### ## ### ########## ##### ##### ###### # ## # # ## ### ### #### # # ######### ############# ### # ##### ## ## ## ## # # ## ############## ########## ## #### #### # ## ### ############ ########## ## # ## # # # ## # ################# ####### # # ## ## # ## ## #### ## ######################### # ## ### ## ## ## # ### ################### ##### # ### ########### # ##### # ## ######################### ######## ##### ### # # #### ## ### ##### # ################ ## # ## ##### ## ## ## ## ####### # #### ####### # # #### ### ###### ## ## ###### ######## ## ## ## ###### ## ### #### ##### ################## # ## ###### #### ############################## # # ###### ################################# ## # ####### ############################### # # ### ### ### ########## ##### ############## ###### ### # ############## #### # ### ### ## ### # ######### ######## ## # ## ### ### ######## ######### ## # ### ######## #### ##### ## # ## # ###### #### ### ## ## # ### ############### ## ## ## ####### ###### # # # ###### # ############ #### # ######## # ################## # ###### ################ ### # ### ###### ##### ### # ###### # #### ######### # ####### # ##### #### #### ### ### ## # #### ### # ##### ## #### # ### # # ######## ##### ## #### ## # ####### ##### ## ### ### ## ###### #### ###### ## # ##### ## ## ##### ## # ###### # # # ## # # ## # #### ## # Brooks ## #### ## ####### #### ## # ### # # ## ## # ## ### ### ### ### # ## ######### ## # # # ## # # ### ###### ######## ## ######### # ### ## ############ # # #### ## ######## #### # ## # ## # ## #### ####### ##### # # # # # ## ####### ## #### ############# # ## ## # ### ## #### # ####### ####### ### # # # ##### #### ##### ############ # ## # ## ##### ############### ## # # # # # ###### ### ####### # ## # # # ###### ### #### # ### # #### # # ######## ## ############### ## # # ### ### # ## ####### ### ######## ####### ## ######## # ########### ################# # # ##### ## ### ## ################ ## ##### # # ##### ############### ## # ## ###### ####### ##### ## #### ########## ### # ### ##### # ######### #### ########## ### # # ## ## # ##### # # #### ###### # #### #### ## ## ## ### # # ##### ## ##### ## # ####### ## #### #### ## ## ### ### ##### ########## ### #### #### ### ### ##### ## ## # # # ##### ## ### ####### ### ## #### ## ############ #### # # # ### ## ###### ### ###### # ### # ## # # ## # ###### ## ## # ## ## ### # # # ## ############ ## # # #### ## ### #### ## #### ## # ##### ## ####### ##### # # ### ## #### # #### ##### ######## ## # # # # ###### # # # ##### ########## ############# ## # ## ########## # # # #### ###### ## ############ ############### # # # ### ## # ##### ### ###### # ###### ################## # # ## ###### ###### # ##### ## ### ### ########### #### ### # ### ###### # ## ## ##### ##### ###### ################ ############### ############## # ######## ####### ######## # ######## ### ####### ##### ##### ####### ### ################ # #### #### #### # ## ## ######## #### ## ### ### ### ####### # ##### ### ####### ## ## #### #### ##### # # #### ### #### ## #### ###### # # ## ######## ######## ####### ########### ### ####### # #### ### # ############ ######## #### ###### #### ## #### ### ###### # # ###### # ####### ########## #### #### ## # ##### # ##### #### # ## #### ### #### ### ###### ########## ####### ## ### ## ### ######## #### # #### ### # ################ ## # # ### ##### ### # # #### ##### ###################### # ## ### ########## # ## # ## # ########################### ## ##### ######## # # ## ######### ####### ####### ####### # ## ########## # # ### ## # # ################## ######## ## #### ##### ### ## ########## ############### ### ##### ### ## # ### ####### ############# # ###### # # # ## # # #### #### # ############ ######### # # ### ### # # # ##### ## # ## ##### ###### ## # # # # # ### ## ############ ##### # ########## ####### # # # ## ########### ### # #### #### # # ## # ## ###### ## #### # ############ # # ## ## # # ## # ### ### ###### ### # #### ### ### #### # ## # ##### ### ####### ###### # # ####### # # ########## #### # ## # ## ## # # ## # ## ## # # # ## # ### ## ## #### # ##### # ### # # ### # ### #### ## # ## #### # # # # ### # # # # # # # ## # ## ## ### # #### ########## Figure 22. Bow Basin irrigation districts 1999 crop group distribution. ## #### #### ########### ####### ############ ########### ########## # ### ### ############ ####### #### #### ### ## # # ###### ##

# # # # ### # # ## Raymond ## ########## #### # # ##### ## # ## ## ## ## # ## ## # # ###### ### ## # ## ## ## ######## # # #### ## # # ############ ######## ### #### # ##### ##### #### # # # ## ###### ## ### ##### # # ### ####### ### ##### ## # ## ### ## ### ## # ### ## # ### # ##### # # # # ### #### ## # #### ##### #### # # #### ### ## ###### # # ### ## # # ## # ## # ### # # # # ## ## ###### ### # # ## ### # # ## # ## # ### ####### # # # # # # ## # # # ### ### ## ## # ### # ### # #### ## # # # ## # ## #### #### ## ## # Specialty crops ## #### ##### ### ## #### Oil seed crops # # # Forage crops

### ############# # Cardston ### ################ ### ### # ######### ## #### Cereal crops # ## ###### ## ### ## ########## ## # # ### ## # ####### # #### # ### # #### ### ####### #### # ### ### # # # # # #### # ### # # # # #

Figure 23. Foothills irrigation districts 1999 crop group distribution.

59 During the 1990s, the agricultural economic strategy focused on value-added 60 processing of specialty crops and livestock. This strategy has stimulated an increase in the area of forage crops and in the area and variety of specialty crops (Figure 24). 40

Area Current emphasis on value-added processing bodes well for the continued

1979 increase in forage production and specialty crops in the irrigated areas of Alberta,

20 1989 and probably a continued decrease in the area of cereal crops. Most specialty crops require high heat units and a dependable supply of moisture that are

Percent of 1999 available only in southern Alberta. In particular, growth in the areas of potatoes and sugar beets could accelerate with the recent arrival or expansion of several 0 Cereals large, world-class processing facilities. Much of the meat processing industry is also linked to irrigated forage production and the numerous large feedlots in southern Alberta. Local processing of oilseeds and the introduction of new, 60 higher yielding varieties of canola, are expected to stimulate an increase in the production of oilseeds.

40 While shifts in the irrigated crop mix may have significant implications on Area crop water requirements for specific irrigation blocks, they are not likely to represent a substantial change in the overall crop water requirement, considering 20 all blocks and districts. The crop mixes and water requirements for 1999 and for

Percent of a scenario reflecting the trend toward a major shift from cereal crops to forage and specialty crops, are shown in Table 8. The crop water requirements were not 0 significantly different in the two cases presented, assuming that both crops are Forages irrigated to their respective full water requirements. The weighted-mean crop requirement increases from 498 mm to 507 mm, an increase of 1.8%. 60 On-farm irrigation management and irrigation methods will likely be more significant than changes in the crop water requirements in increasing future water requirements. Specialty crops generally have higher input costs and higher 40 market values than cereal crops. Irrigation water users tend to be more diligent in Area managing their operations for higher value crops, which generally results in higher irrigation applications. The continuing shift in irrigation methods, from 20 labour intensive surface irrigation to less onerous automated sprinkler systems,

Percent of would also encourage higher applications to increase yields. Both these issues are dealt with in subsequent sections of the report. 0 Oilseeds Table 8. Current and possible future crop mix and water requirements. 60 90th Percentile 1999 Future Scenario Crop Category Crop Requirement Crop Mix Crop Mix Cereal– LoCU1 390 mm 24.2% 8% 40

Area Cereal– HiCU 480 mm 10.9% 10%

20 Forage – LoCU 370 mm 13.2% 20%

Percent of Forage– HiCU 680 mm 28.2% 30% 0 Specialty Crops Oilseed 450 mm 10.0% 12%

Specialty– LoCU 380 mm 5.6% 9% Figure 24. Historical cropping patterns within Specialty– HiCU 560 mm 7.9% 11% irrigation districts. Weighted-Mean Crop Requirement 498 mm 507 mm 1CU = consumptive use.

60 3. On-farm Irrigation Systems and Application Efficiencies During the past 40 years, there have been substantial gains in on-farm efficiencies due to changes in irrigation methods and technological improvements in equipment. Current (1999) on-farm efficiency was estimated to be about 71%. Efficiencies will continue to improve. Given the current state of technology and the type of irrigation practiced in southern Alberta, an application efficiency of 75% is considered to be appropriate for long-term planning. The various components of an on-farm water balance and factors affecting on- farm application efficiency are shown in Figure 25.

Gross On-Farm Demand = the volume of water delivered through the irrigation project conveyance works to meet specific on-farm system demand. Evaporation "E" = the amount of water lost due to Gross Outflow Water "O" = the evaporation through aerial amount of applied water On-Farm application, the crop that flows off an irrigated Demand canopy, soil, and surface area as surface run-off from irrigation systems. sprinkler systems, or as Farm Diversion "D" Evaporation tailwater from surface = the net amount of irrigation systems. water that is actually Losses Lost Runoff "L" = diverted and delivered that portion of the into the on-farm, in- Lost "Outflow" amount field irrigation system. E Runoff not re-captured for further irrigation O L use. D

Down-Time Re-captured Flow-By Stored S P Runoff Down-Time Flow-By = the Soil Moisture Re-captured Runoff "R" = volume of water not diverted to that portion of the "Outflow" the farm due to on-farm system Deep amount re-captured for shut-down and/or temporary Percolation further irrigation use suspension of irrigation. Shut- Stored Soil Moisture "S" = elsewhere within the downs occur to accommodate the net amount of water that irrigation project. moving equipment between infiltrates the soil surface and Deep Percolation "P" = the adjacent sets, or to carry out remains in the active crop root portion of the applied water repairs. Shut-downs can occur zone as stored soil moisture to that infiltrates the soil surface automatically within self- support crop consumptive and percolates through the soil propelled systems. requirements. profile to a depth below the active crop root zone, where it becomes unavailable for crop consumptive use. Figure 25. Components of the on-farm irrigation water balance.

61 For the purposes of this report, on-farm application efficiency (Ea ) is defined as the ratio between the amount of irrigation water applied and retained within the active root zone and the total amount of irrigation water delivered into the on-farm system. The magnitude Application Stored Soil Moisture, S = X 100 of each of the components of the on-farm water balance Efficiency,E (%) Farm Diversion Amount, D a is, to a great extent, dependent on the irrigation method and the equipment used to apply water to the soil. For instance, for a surface irrigation system, deep percolation,P , and outflow,O , is expected to be high since fields are flooded and surplus water is drained off. For a high pressure sprinkler system,OP and would probably be small, but evaporation losses,E , may be relatively high. During the past century, irrigation methods and equipment have changed drastically. During the first half of the century, surface irrigation systems (sometimes referred to as gravity systems) predominated, primarily operating as wild flood schemes. During the 1960s, land leveling to control field slopes became more common, and surface irrigation continued to expand (Figure 26). The adoption of border-dyke and furrow methods to control the flow of water over the land increased the effectiveness and efficiency of surface irrigation. The advent of aluminum pipe after World War II marked an increase in sprinkler irrigation systems and more efficient water use. Sprinklers also enabled irrigation of rolling land and land "above the ditch". Sprinkler systems did not significantly impact irrigation expansion until the 1960s when labour-saving, wheel-move systems became popular. In the 1970s, centre pivot irrigation systems began showing up. Sprinklers, both wheel-move and centre pivot, began to replace surface irrigation systems. Technological advances in centre pivot systems during the past 20 years, including the addition of corner systems and low pressure application devices, have greatly improved their efficiency and effectiveness. The centre pivot system, with its diversity and adaptability, is currently the system of choice. There is only a minor amount of purchasing and development of any other irrigation system or method in Alberta. Pump and sprinkler technology enabled the irrigation of land with rolling topography and land above the ditch. This considerably reduced the labour involved in irrigation farming. These factors contributed to more than a doubling of the irrigated area in Alberta since 1970.

800

600 Pivot 400

Wheel-move, etc. Irrigated Area 200 (hectares in thousands) Surface 0 ‘65 ‘70 ‘75 ‘80 ‘85 ‘90 ‘95 Year Figure 26. Irrigation expansion and on-farm irrigation methods.

62 Through many years of system testing, field monitoring, literature searches and consultations with other jurisdictions, a range of application efficiencies for each type of irrigation equipment and method was derived and accepted as an industry standardin Alberta . There are many factors that can affect the efficiency for any given system or method. For instance, properly levelled and designed surface systems can have efficiencies up to 75%, whereas poorly designed and managed surface irrigation systems may have efficiencies less than 60%. A low pressure, down-spray sprinkler can range in efficiency from 75% to 90%. Design of the sprinkler nozzle, spray devices, capacities and pressure at which water is ejected must be in keeping with site-specific soil texture, topography and agro- climatic conditions to maximize the efficiency of the system. In addition, farm management can have a major impact on efficiencies, even on the best designed systems. Based on AAFRD's research, the following application efficiencies are considered to be representative of various on-farm irrigation methods and systems in Alberta. On-farm irrigation methods ! Surface (undeveloped) - 30% generally fall into three ! Surface (developed) - 65% categories: ! Surface irrigation ! Hand-move sprinklers - 65% ! Sprinkler irrigation ! Wheel-roll sprinklers - 68% ! Micro or drip irrigation ! Centre pivots (high pressure) - 74% ! Centre pivots (low pressure) - 80% On-farm irrigation systems are comprised of the actual AAFRD has tracked on-farm methods and equipment in the 13 irrigation works used to apply water to districts for several decades. Based on this information and the system/method the land. In the Irrigation application efficiencies, a chronology of average district on-farm efficiency District Model, 18 different changes since 1965 was computed (Table 9). On-farm application efficiencies system-types are represented improved markedly from 1965 to 1995, largely due to the shift from surface among the three application irrigation to sprinkler irrigation, and more recently, to centre pivot systems. The method categories. magnitude of the improvement varies from district to district, depending, to a degree, on crops grown and the extent to which irrigation is a critical input to crop yields. Table 9. On-farm application efficiencies based on methods and equipment. Average Efficiency for Year (%) Irrigation District 1965 1980 1990 1995 1999 Aetna 30 33 44 45 65 Bow River 37 59 66 66 71 Eastern 32 53 64 64 67 Leavitt 30 33 42 42 65 Lethbridge Northern 32 56 67 69 73 Magrath 31 50 56 58 72 Mountain View 30 31 32 32 32 Raymond 32 52 61 66 72 Ross Creek 40 49 51 53 N/A St. Mary River 35 64 70 71 73 Taber 38 65 68 69 73 United 31 39 40 40 61 Western 35 51 67 68 69 Weighted Mean 34 58 60 67 71

63 The average, overall on-farm application efficiency in 1999 for all the irrigated areas in southern Alberta was estimated to be 71%. This value would probably be slightly higher for private irrigation, due to the predominance of sprinkler systems in those operations. Significant gains in on-farm application efficiencies have been realized. It is expected improvements will continue in the future as producers shift to more efficient systems and as irrigation management techniques improve. With the current state of technology and with systems in common use today on the Canadian prairies, average on-farm efficiencies beyond 80% are unlikely. Well- designed centre pivot or linear sprinkler systems with low pressure drops range in application efficiency from about 75% to 90%, depending on site-specific soil textures, topography and climatic conditions. The mean efficiency for such systems is about 80%. A widespread shift to drip or trickle irrigation systems with 90% efficiencies is unlikely for the crops irrigated in southern Alberta without a major change in commodity prices. For the foreseeable future, a 75% on-farm application efficiency is considered to be a reasonable target for planning purposes. An on-farm efficiency of 75% was assumed for determining the 1991 Regulation licence volumes.

4. Irrigation Management Practices It has long been recognized that irrigation farmers in Alberta apply less water to their crops than that required for optimum yields. Based on monitoring conducted during the past five years, it is estimated that irrigation water users are meeting, on average, about 84% of water requirements for optimum yields. This level of irrigation management, or water application, has increased during the past 10 years, and will continue to increase. However, it is believed the level of irrigation management will not increase beyond 90% of optimum for the types of crops grown, and cultural and harvesting practices in southern Alberta. Approximately 60 irrigated fields were monitored each year from 1996 to 2000 to determine the extent to which actual irrigation crop water management compared with crop water requirements for optimum production. The crop water requirements for optimum production were estimated for various crop types and regions using the Lethbridge Research Station Irrigation Management Model (LRSIMM). LRSIMM simulates evapotranspiration and soil moisture conditions using the Jensen-Haise equation and calibrated crop type coefficients. The timing of optimal irrigation applications was determined based on the objective of keeping soil moisture in the irrigated field above 70% of field capacity for centre pivot systems, and above 50% of field capacity for wheel move and surface systems. It was assumed pivot systems added 25 mm in each application and wheel moves added 72 mm. Each application brought surface systems up to field capacity. Actual applications were monitored. Computation results for optimal water requirements and actual crop water management were compiled by crop type, by on-farm irrigation system and by region. Modelled versus monitored crop water requirements or consumptive use (CU) varied by crop type (Table 10). Note that the monitored CU includes precipitation and irrigation as well as changes in soil moisture. Alfalfa had the highest crop water requirement for optimum production (638 mm), almost double the requirement of silage barley, the crop with the lowest water requirement. On average, irrigation water users are meeting about 84% of the crop water required for optimum production. The consumptive use ratios range from 77% for alfalfa to 98% for sugar beets. The low consumptive use ratio for alfalfa may be due in part to the fact that the LRSIMM model computed requirements throughout the growing season until the first killing frost. In some regions, two cuts of alfalfa is the common practice, rather than three cuts.

64 Irrigation farmers generally do not irrigate during harvesting operations. High input costs associated with higher value crops, such as sugar beets, and the more serious consequence of lower than optimum yields, may foster higher levels of irrigation management for specialty crops. Table 11 shows the variation in on-farm management by irrigation method and system type. On average, there was very little difference in the percentage of optimum requirements consumed by crops grown under centre pivot (84%) and wheel move (81%) systems. Surface systems met, on average, 71% of the crop water requirement.

Table 10. Variation in on-farm water management by crop type. (Five-year averages for all regions - CU = consumptive use)

Crop Water Requirement - Consumptive Use (CU) Monitored CU Crop Type Optimum CU (mm) mm % of Optimum

Alfalfa 638 494 77

Barley 352 315 90

Silage barley 322 285 89

Canola 390 334 86

Soft wheat 437 361 83

Sugar beets 525 514 98

Wheat 419 360 86

All crops 469 396 84 (weighted mean)

Table 11. Variation in on-farm water management by irrigation system type. (1996 to 1999 averages for all regions and all crop types. CU = consumptive use)

Crop Water Requirement Average Annual % of Fields System Optimum CU Monitored CU Over-irrigated Under-irrigated (mm) at Least Once at Least Once mm %

Centre pivots 468 401 84 11 57

Wheel moves 481 381 81 34 60

Surface 437 357 71 100 20

65 All the surface irrigated fields, 34% of the wheel move fields, and 11% of the centre pivot fields were over-irrigated at least once during the growing season. Examination revealed that 69% were over-irrigated due to operator decisions, such as using 12-hour rather than 8-hour sets, or starting irrigation too early in the season. System design problems, such as excessive run lengths or an incorrect nozzle package for the soils, accounted for 31% of the over-irrigation. Only 20% of surface irrigated fields were under-irrigated at least once. In comparison, close to 60% of the wheel move and pivot irrigated fields were under-irrigated at least once. Sprinkler under-irrigation tended to occur in years that were cool and wet. Almost all of the under-irrigation could be attributed to operator decisions, such as starting too late or quitting too early. None of the under-irrigated fields were a result of insufficient delivery of water. Long-term normal corn heat units,1996 to 2000 monitoring-period corn heat units, and precipitation provide an indication of the variation in climatic conditions in the six regions where monitoring was carried out (Table 12). As expected, the regions with the lowest heat units during the study period (Strathmore and Brooks) had the lowest crop water requirements. The average application ratios ranged from 72% in the Strathmore region to 93% in the Bow Island region. The highest levels of irrigation management were in the Medicine Corn heat units are indicators Hat and Bow Island regions where long-term normal heat units are highest and of the capacity of a climatic normal precipitation is lowest. These regions have a higher percentage of area to grow crops requiring specialty crops than the other regions. (The Taber Irrigation District has the relatively high temperature highest percentage of specialty crops of all the districts, however, AAFRD's regimes. They are, essentially, Taber district office monitored projects in both the Taber and Bow River the accumulation of heat, districts.) The lower levels of irrigation management in the Strathmore and measured in degree-days above Brooks regions may be a reflection of the lower percentage of specialty crops. A certain thresholds, during the portion of the alfalfa grown in the Western and Eastern irrigation districts, their growing season. predominant crop, is also managed for two cuts rather than three. The LRSIMM was used for estimating crop water requirements during the full frost-free period.

Table 12. Variation in on-farm management by region. (Five-year averages for all crop types)

Crop Water Requirement Corn Heat Units G.S. Precipitation2 Region Monitored CU1 Long-term 1996 to Optimum CU Long-term 1996 to Normal 2000 Mean (mm) mm % Normal 2000 Mean (mm) (mm)

Strathmore 418 301 72 1993 2079 258 220

Brooks 451 360 80 2256 2418 217 185

Lethbridge 473 398 84 2294 2424 254 219

Taber 496 411 83 2359 2617 219 179 Bow Island 484 449 93 2474 2529 212 165

Medicine Hat 492 454 92 2414 2522 216 172

Average 469 396 84 2298 2432 229 190 1CU = consumptive use. 2G.S. = growing season.

66 Overall, the level of irrigation crop water management in 2000 is estimated to be about 84%. That is, the level of consumptive use, on average, is about 84% of that required for optimum crop yields. The level of crop water management is expected to increase in the future for the following reasons. ! There will be a continued shift in irrigation methods from surface irrigation to sprinkler irrigation. ! There will be a shift in irrigated crop types from cereals to higher value specialty crops. The gains made from this shift may be partially offset by a shift from cereal crops to forage production. ! Training and education of irrigation farmers on techniques and benefits of higher levels of crop water management will increase. ! Improvements in irrigation scheduling technology and widespread use of scheduling techniques will continue. ! On-farm system design will improve. While improvements will be made, it is a consensus of opinion among irrigation district and AAFRD staff that the level of crop water management is unlikely to increase beyond 90% of optimum, for the crops grown, and the cultural and harvesting practices in southern Alberta. This conclusion is supported by research and the opinions of irrigation practitioners in the north- western United States. The 1991Regulation licence volume was based on irrigating to the optimum crop water requirement, implying a 100% irrigation management factor. The prevailing irrigation management factor in 1991 was estimated to average 80%.

B. IRRIGATION DISTRICT DISTRIBUTION SYSTEM The three main tributaries of the South Saskatchewan River– the Red Deer, Bow and Oldman Rivers– rise in the Rocky Mountains and foothills of southwestern Alberta and flow eastward across the prairies. The St. Mary River, the Belly River, and its major tributary, the Waterton River, rise in the mountains of Montana and flow northeast to join the Oldman River near Lethbridge. On average, about 75% of the total annual flow of these rivers originates in the mountain and foothills region. Although variable from year to year, the mountain and foothills runoff is more dependable than that of the prairies. In the late-1800s, government resource administrators observed the frustrations of settlers attempting to earn a living farming the dry prairie. They concluded the waters of the Rocky Mountains should be made available to the settlers to enable them to remain on the land. Irrigation was promoted and projects were developed by individuals and by corporate land developers. The development of the irrigation projects that were eventually to become the current 13 irrigation districts typically involved four basic components. ! Works to divert water from the source, usually a river. ! Works to convey water from the source to the irrigation district. ! Distribution works within the district to convey water to individual farmers. ! On-farm works to apply water to the land. For 11 of the 13 irrigation districts in Alberta, the first two components, referred to as headworks, are owned and operated for multi-purpose use by AENV. The Eastern and United irrigation districts own and operate their own headworks. The UID is negotiating transfer of their headworks to the province. Distribution works are owned and operated by the individual districts. The on- farm works are farmer-owned.

67 1. District Characteristics In the early years, the layout of the distribution system was aimed at getting as much land as possible under the ditch, so it could be irrigated by surface methods. Canals were located and designed to minimize earthwork, which was dependent on horse-drawn equipment. As such, canals usually followed the contour of the land. Seepage from canals was unchecked and high in some areas. Structures were often made of untreated timber. Washouts were common and maintenance was high. In some areas, the landowners did not greet the arrival of irrigation water with the enthusiasm expected. Irrigation uptake by dryland farmers was particularly slow and spotty where there were good prospects for a dryland crop in most years. However, both irrigating and non-irrigating landowners came to depend on the canals for their domestic and stock watering supplies. Communities used the irrigation canals to meet their municipal needs. The ratio of irrigated area to canal length varied from project to project. These ratios have persisted through the years and are a significant characteristic of the districts of today (Figure 27). Low ratios have major implications for funding, operation, maintenance and efficiencies of district works. The layout and design of the distribution systems in the early years established patterns of land use and water dependencies that were inherited by today’s districts. With this inheritance came an inefficient, high maintenance distribution system, and in some cases a limited ability to make rational changes to the system without major impacts on the landowners and the communities dependent on the canals for their water supplies. By the 1960s, infrastructure within the irrigation districts was in a serious state of disrepair. Without major rehabilitation, water supplies in many areas would have been threatened. The required rehabilitation was clearly beyond the fiscal capability of water users within the districts, so assistance from the province was sought and granted. Since 1969, AAFRD and AENV have cost- shared with the districts the rehabilitation of infrastructure. To date, more than 4,200 km of canals have been rehabilitated, representing about 55% of the district conveyance works (Figure 28; Table 13). This work is continuing. Most of the rehabilitation work has been funded with AAFRD and AENV cost-sharing. Some districts, such as the EID and SMRID, have solely funded part of their rehabilitation programs.

100

(ha/km)

Irrigation Density 20

0 AID BRID EID LID LNID MID MVID RCID RID SMRID TID UID WID Average

Figure 27. Ratio of assessed irrigation area to length of distribution system (district density).

68 100

(%) 40

rehabilitated

Percent of works 20

Rehabilitation Completed 0 AID BRID EID LID LNID MID MVID RCID RID SMRID TID UID WID Total Figure 28. Progress on rehabilitation of irrigation district works.

Table 13. Irrigation district distribution systems.

Rehabilitated Conveyance Works1 Total Unrehab'ed Rehab’ed Irrigation District Percent Canals Canals (km) Pipelines Total and Rehab’ed (km) (km) Rehab’ed Unrehab’ed Earth Lined (km) (km)

Aetna 17 1 0 10 11 28 40%

Bow River2 473 202 217 189 609 1082 56%

Eastern2 890 386 218 428 1032 1921 54%

Leavitt 18 20 3 15 38 56 68%

Lethbridge Northern 369 69 106 170 344 714 48%

Magrath 26 36 1 39 76 102 74%

Mountain View 9 17 0 12 28 37 77%

Ross Creek 7 9 1 2 13 19 65%

Raymond 55 124 4 84 211 267 79%

St. Mary River2 563 424 204 590 1218 1781 68%

Taber 24 84 89 159 333 357 93%

United 120 52 14 52 118 239 50%

Western 981 126 38 49 213 1194 18%

Total 3552 1550 895 1798 4243 7796 54%

1Rehabilitated works include district works constructed with provincial and district cost share funding. 2Data for BRID, EID and SMRID current to November 1999; all other districts current to June 1999.

69 The rehabilitated works are much more efficient than the works they replaced. Canals have been lined where seepage was significant and seepage has almost been eliminated. Waterlogged and salinized land is being reclaimed. More constant canal side slopes and bed widths, and gravel armouring on side slopes, have lowered maintenance costs and helped to convey water more effectively. Canal alignment changes have been made to accommodate modern irrigation techniques. Automation of appurtenant structures (drops, checks, wasteways, etc.) has reduced response time, spills and return flow. In recent years, many districts have replaced small canals with pipelines. The capital costs of pipelines are often competitive with lined canal costs, and pipelines offer significant advantages, including the following. ! No tailouts, therefore minimizing return flow. (About 90% of installed pipelines are closed systems). ! Increased efficiencies by eliminating seepage and evaporation losses. ! Eliminating canal right-of-ways, thereby increasing the irrigable land. ! Commonly used PVC pipe has a life expectancy of 100 years. ! Low maintenance costs. Only appurtenant equipment (flanges, inlets, flow meters, etc.) requires maintenance. ! Less danger to the public than an open channel. ! Less opportunity for water contamination. ! Static head within the pipe can reduce or eliminate pumping costs. Recently introduced 1200-mm diameter PVC pipe can carry flows up to 2.8 cubic metres per second. Proposed 1500 mm pipe will increase the carrying capacity to about 4.2 cubic metres per second . It is expected the districts will continue to upgrade their distribution systems by rehabilitating their canals and replacing the smaller ones with pipelines. As pipelines become more numerous and larger, new issues will arise, such as the effects of water hammer and cyclical surges on the life of the pipes. Changes in water use from pipelines, due to power outages or heavy rains, will have immediate effects on feeder canal flows and water levels. Automation of operations, monitoring and communications will become more critical, to enable timely responses to avoid washouts and minimize spills. Reservoirs are integral components of both the headworks and the irrigation district infrastructure. Alberta Environment and the districts operate 49 reservoirs to supply water for instream flow needs, communities, industries, recreation users, domestic users and stock within the irrigated area of Alberta. AENV operates both onstream and offstream reservoirs that are critical to supplying the needs of the irrigation districts (Table 14). Onstream reservoirs on the Waterton, St. Mary and Oldman rivers are used to store water during the high flow periods–– usually early May to mid-July for controlled releases to meet instream flow needs, and for consumptive uses and interprovincial apportionment commitments during low flow periods. The St. Mary River and Oldman River reservoirs are large enough to carry storage over from most high flow years to supply water needs during periods of drought. AENV also owns and operates eight offstream storage reservoirs within its network of irrigation headworks. The accumulation of storage in offstream reservoirs is constrained by the capacity of the canals conveying water to the reservoirs from the source streams. Most offstream reservoirs are used to accommodate seasonal variations in supply and demand. The offstream reservoirs are not as effective as the onstream reservoirs in contributing to instream flow needs and apportionment. However, some projects, such as McGregor Lake Reservoir, are large enough to provide annual carry-over storage.

70 Table 14. Reservoirs associated with irrigation and other water uses in southern Alberta.

LocationReservoir Live Storage Full Supply Level (dam3 ) Surface Area (ha) Alberta Environment Headworks Reservoirs Sub-totals Sub-totals Carseland-Bow River (BRID) Little Bow 21,078 530 McGregor Lake 351,059 5,100 Travers 104,638446,775 2,265 7,895 Cavan Lake (RCID) Cavan Lake 4,6254,625 135 135 Lethbridge Northern (LNID) Keho Lake 95,635 2,350 Oldman River 490,180585,815 2,425 4,775 Mountain View, Leavitt, Aetna Payne Lake 8,6908,690 240 240 Waterton-St.Mary (SMRID, MID, RID, TID) Jensen 19,000 200 Milk River Ridge 127,297 1,415 St Mary 369,310 3,765 Waterton 111,196626,803 1,095 6,475 Irrigation District Reservoirs Bow River Irrigation District Badger 53,650 890 H Reservoir 2,220 130 Lost Lake 5,050 485 Scope 19,740 80,660 575 2,080 Eastern Irrigation District Cowoki 19,735 730 Crawling Valley 130,500 2,515 J Reservoir 615 115 Kitsim 26,520 690 Lake Newell 320,215 6,495 One Tree 2,345 90 Rock Lake 9,250 225 Rolling Hills 17,515 585 Snake Lake 18,230 105 Tilley "A" 33,300 620 Tilley "B" 38,235 616,460 1,410 13,580 Lethbridge Northern Irrigation District Park Lake 740 85 Picture Butte 1,600 2,340 100 185 Raymond Irrigation District Corner Lake 495 15 Craddock 615 13 Factory Lake 370 1,480 29 57 St. Mary Irrigation District Bullshead 125 13 Chin 190,330 1,590 Cross Coulee 2,590 85 Forty Mile 86,345 745 Murray 30,590 1,665 North East 2,095 210 Raymond 1,600 60 Sauder 37,745 1,245 Seven Persons 1,355 60 Sherburne 10,625 410 Stafford 23,315 490 Yellow n/a386,715 1,105 7,678 Taber Irrigation District Fincastle 3,085 185 Horsefly 9,250 565 Taber Lake 6,415 18,750 405 1,155 United Irrigation District Cochrane Lake 3,100 3,10090 90 Western Irrigation District Chestermere Lake 5,180 260 Langdon 7,895 13,075 245 505 Total (all reservoirs) 2,825,288 44,850

71 The 38 reservoirs owned and operated by the irrigation districts are all offstream reservoirs that depend primarily on canal flows for their water supplies. Reservoir storage is essential to provide water supply security to irrigation water users who would otherwise be dependent on highly variable river flows to meet their needs. Reservoirs within districts provide operational flexibility and reduce response times to meet changes in water demands. Many reservoirs are strategically located to recapture operational spills and return flow, thus improving water use efficiencies within districts. It is expected the continuing need to improve efficiencies will stimulate further reservoir developments within the districts.

2. Canal Seepage When the 1991Regulation licence volumes were established, seepage was estimated to be 13% of the total volume for all districts. Research conducted since 1996 indicates that the rate of seepage from canals is much lower than estimated in 1991. Substantial progress has been made since 1991 in rehabilitating irrigation district infrastructure and further reducing seepage losses. Seepage from district works has been estimated to be about 89,800 cubic decametres or 2.5 % of theRegulation licence volume. This amount will be reduced further with continuing rehabilitation. Data from 26 ponding tests conducted in various irrigation districts indicated that canal seepage varied from 0.0032 cubic metres per square metre of wetted area per day to 0.1312 cubic metres per square metre per day, with an average of 0.023 cubic metres per square metre per day. The results from the tests and typical cross-sections for various canal sizes were used to derive relationships between seepage rates, canal size (capacity) and soil texture. Information on soil texture along canals within the irrigation districts was taken from the Agricultural Region of Alberta Soils Inventory Database. Canal lengths, capacities and soil textures were inventoried for each district. Seepage rates for canal segments were derived based on the percentage of each of the three soil texture groups existing along the canal length. Drains were not included in the computations. Many of the drains are natural channels that typically have low seepage rates. Drains that carry a natural flow as well as irrigation return flow would have negligible incremental seepage caused by irrigation water. Using seepage rates as shown in Figure 29 and canal and soil characteristics, total seepage for each district was computed based on the following assumptions. ! Seepage was zero for all pipelines and lined canals. 0.025 Compacted earth-lined canals were assumed to have the 0.02 Coarse seepage characteristics of canals with fine textured soils. 0.15 ! The canals were "checked up" 0.1 Medium to their maximum hydraulic head regardless of the flow. 0.005

Seepage rate Fine (Canal check structures are used 0 to assure adequate head at the 0 10 20 30 40 50 60 farm turnouts.) ! The canals would be operated

(cubic metres per second per kilometre) Canal capacity (cubic metres per second) for 150 days each year. Figure 29. Seepage rates for various soil texture groups and canal capacities.

72 The total canal seepage for each district is given in Table 15. Note the seepage computed is based on soil texture and infrastructure characteristics in 1999. As such, it is independent of the area irrigated or the gross diversion. About 5,000 km of canals have the potential to seep. The SMRID, EID and the WID account for two-thirds of this total. The SMRID and EID are Alberta's largest and second largest irrigation districts, respectively. Rehabilitation of conveyance works is well advanced in both these districts; about 69% in the SMRID and about 54% in the EID (Table 13). The WID is the fifth largest irrigation district; only about 18% of its conveyance works have been rehabilitated. The rate of seepage from the canals varies substantially among the districts, depending on the size of the canals and soil textures. The total annual seepage is estimated to be about 89,753 cubic decametres. The EID has the highest seepage volume, 23,672 cubic decametres, which represents 2.6% of the district's proposed licence volume as established in the 1991Regulation . The WID has a seepage volume similar to the EID. However, this represents a substantially higher portion (6.8%) of theRegulation licence volume, in large part due to the low percentage of canals that have been rehabilitated.

Table 15. Summary of seepage losses from irrigation district canals and drains. Water Management Study 1991 Regulation (Based on Ponding Tests) Seepage Estimates Irrigation District Length of Annual Seepage Loss Volume Percent of Seepable (dam3 ) Licence 2 Volume Percent of 1 Canals (dam3 ) Licence Volume (km) Volume 1 Aetna 17 170 1.5%3,136 28.2% Bow River 641 13,799 2.2% 69,939 11.3% Eastern 1,242 23,672 2.6% 108,548 11.8% Leavitt 39 238 1.6% 4,001 27.0% Lethbridge Northern 422 5,346 1.4% 47,379 12.1% Magrath 62 491 1.2% 5,418 12.9%

Mountain View 26 224 2.3% 1,324 13.4% Raymond 181 1,971 2.0% 8,030 8.0%

Ross Creek 18 116 3.1% 370 10.0% St. Mary River 1,003 18,084 2.0% 82,595 9.3% Taber 94 1,289 0.7% 14,195 7.3% United 173 1,111 1.3% 9,646 11.5% Western 1,101 23,242 6.8% 117,183 34.2% Total or weighted mean 5,019 89,753 2.5% 471,764 13.0% 1 For theRegulation licence volume, see Table 4. 2 Seepable canals = all canals without membrane or concrete lining.

73 The seepage losses used for determining the licence amounts for the 1991 Regulation limits (Table 4) were based on the Moritz formula, as suggested in the United States Bureau of Reclamation's design manual. The current estimates are only about 19% of the 1991 estimates for two reasons: ! Rehabilitation of irrigation infrastructure has made substantial progress during the past 10 years, eliminating or reducing the rate of seepage from canals. In particular, numerous reaches of small canals have been replaced by pipelines with zero seepage; and ! Ponding tests on unrehabilitated canals indicated a rate of seepage that is much less than the literature values used in the 1991Regulation licence volumes. For instance, the ponding tests indicated an average seepage rate of 0.023 cubic metres per square metre per day. The 1991 estimates were based on a seepage rate of 0.125 cubic metres per square metre per day for all unrehabilitated canals, which is 5.5 times the average rate computed from the ponding tests. The 1999 estimates of seepage losses represent only 2.5% of the Regulation licence volumes. At present, about 54% of the district infrastructure has been rehabilitated (Table 13). Most of the larger canals, and particularly canals with significant seepage, have already been rehabilitated, eliminating a large portion of seepage from the conveyance works. Taber Irrigation District, with 93% of its works rehabilitated, has an annual seepage loss of 0.7% (Table 15). Based on this experience, andwith continued rehabilitation in all other districts, it is conservatively estimated seepage losses could be reduced to about 1.5% of the gross diversion, or 54,000 cubic decametres.

3. Evaporation Canal and reservoir evaporation losses from the current district infrastructure have been estimated to be about 142,016 cubic decametres, or about 3.9% of the proposed licence volume. In establishing the 1999Regulation licence volume, reservoir evaporation was estimated to be 3.6% of the gross diversion. Canal evaporation was not considered in the 1991 estimate. In the future, reservoir evaporation losses would increase if new reservoirs were established within the districts. Canal evaporation would decrease slightly if pipelines continue to replace open channels. Evaporation of water applied to crops using sprinkler or surface methods is accounted for as a component of on-farm system inefficiencies. Evaporation from open water surfaces of canals and reservoirs owned by the irrigation districts is an additional demand on the districts' water allocations. Evaporation from headworks canals and reservoirs is usually accounted for in the headworks licences issued to AENV and, as such, will not be dealt with in this section. Evaporation from open water surfaces varies from year to year depending on factors such as temperature, relative humidity, solar radiation and surface areas of canals and reservoirs. Several methods have been developed for estimating evaporation from open water surfaces based on commonly recorded weather parameters. After an extensive study of options, AENV has adopted the Morton method for evaporation computations. The approach was developed in the late 1960s by F.I. Morton, and is based on energy balance and vapour transfer relationships (Morton 1968). The Morton method is being used to compute evaporation in AENV's Water Resources Management Model.

74 AAFRD examined five equations for computing potential evapotranspiration, primarily using data available in the Gridded Prairie Climate Database. They found the Priestley-Taylor method best replicated research results. This method was selected by AAFRD to compute potential evapotranspiration at the grid sites in southern Alberta. The Distribution Working Group examined the Morton, Priestley-Taylor, and other methods for computing surface water evaporation. A primary consideration in determining the suitability of the various methods is the availability of the input data for the study period. The working group found that the Priestley-Taylor method provided estimates similar to the Morton method. Since the data for the Priestley-Taylor method were already assembled, that method was selected to provide estimates of canal and reservoir evaporation. The difference between evaporation and precipitation which falls directly on the water surface is referred to as net evaporation. Net evaporation from canals and reservoirs would be a loss to the distribution system charged against the district licences. Net evaporation from canals was estimated for each district based on an inventory of sizes and lengths of canals, surface areas, and net evaporation estimates for the general locations of the districts. Estimates were based on typical canal geometry, assuming the canals were running full or checked to their full capacity during the irrigation season. Mean annual canal evaporation estimates are shown for each of the 13 districts in Table 16. The total canal net evaporation for all districts was estimated to be 19,245 cubic decametres, or 0.5% of the licence volume. This is a very small component of the total demand within the districts. Canal evaporation was not included in the 1991 computations of the proposed licence amounts. Evaporation from most reservoirs within the irrigation districts was computed in the WRMM modelling conducted by AENV. The evaporation computations were based on simulated weekly reservoir levels and surface areas. These surface areas were sometimes considerably less than the areas at full supply levels, particularly in critical low runoff, high demand years, when the reservoirs would be drawn down for water supply purposes. The reservoir evaporation demand was variable from year to year. Each scenario of water demands and operational characteristics would have unique reservoir evaporation demands. In the 1991 computations of the licence volume, evaporation demands for the irrigation district reservoirs were input to the model as a fixed demand on the system. For comparison purposes, the Distribution Working Group computed the mean annual reservoir evaporation for each district based on reservoir surface areas at full supply levels and the mean net evaporation for the general locations of the reservoirs. The estimated reservoir net evaporation loss for each district is given in Table 16. Note these estimates are upper limits of mean annual evaporation. They are probably higher than the evaporation losses computed in the modelling exercise. The total reservoir net evaporation loss for all districts is estimated to be 122,771 cubic decametres, or 3.4% of theRegulation licence volume. This figure compares well with the 1991 estimate of 132,021 cubic decametres. The volume of evaporation loss is primarily a function of district infrastructure characteristics. It will not be significantly modified by changes in the irrigation area or the gross diversion. In the future, canal evaporation will decrease by a small amount as pipelines replace canals. Evaporation would increase with the construction of new reservoirs. While new storage reservoirs can significantly improve district operations and reduce return flows, reservoirs in themselves are water users. This water use should be considered in decisions related to new storage development. Efficient storage sites that maximize the storage capacity to surface area ratio should be given preference.

75 0

0 0

8.1

2.1

1.3

0.5

0.8

0.7

1.2

2.6 3.6 3.6

1.4

%of

Volume

Licence

Regulation

131

117

137

419

1991

Net

7,771

4,055

2,344

(dam )

74,627

10,300

32,120

Evaporation Losses

Volume

132,021

%of

0.2%

2.2%

7.8%

0.3%

0.5%

0.3%

0.9%

0.8%

4.8%

2.9%

0.7%

1.3%

3.9%

Licence

Volume

Total Net

18 39

121 926

567

Evaporation

2,019

5,613

4,375

72.077

42,793

13,407

(dam )

142,016

Volume

777

242

310

5.128

1,717

37,239

67,132

10,226

122,771

(dam )

Net Loss

tudy of Evaporation Losses

185

505

1,155

7,678

2,080

13,580 25,330

Surface

Area (ha)

Reservoirs

eservoirs.

3 3

Number

Water Management S

121

485

257

684

3,181

4,945

2,658

1,242

5,554

19,245

(dam )

Net Loss

Irrigation

. Does not include headworks canals or reservoirs.

Table 4

161

648

627

987

109

280

1,178

4,124

Surface

Canals

Area (ha)

om irrigation district canals and r

181

187 857

529

182

(km)

Total

1,451

1,153

1,192

5,902

Length

Regulation

Irrigation AID District BRID

EID

LID

LNID

MIF

MVID

RID

RCID

SMRID

TID WID

UID Total

Irrigation district canals and reservoirs only For the licence volume, see

Table 16. Evaporation fr

76 4. Return Flow Irrigation return flow is the quantity of water diverted from a source that exceeds the consumptive requirements of the irrigation project, including losses. This surplus water is returned to the river system – not necessarily the source stream – through drainage channels. Return flow is an inevitable consequence of operating an irrigation system. It occurs in large part because variable supplies and demands cannot be perfectly matched in a canal distribution system. The irrigation districts are concerned about return flow for several reasons. Uncontrolled spills and sudden changes in canal water levels can damage canals and increase maintenance costs. Inefficient operations could jeopardize expansion of irrigation. They are also concerned about public perceptions of wasteful management practices and impacts on the source streams. During the past decade, the districts and AAFRD have made a concerted effort to better quantify return flow, to understand the factors affecting it, and to identify ways to minimize it. This effort has involved intensive monitoring and study of small irrigation blocks within the BRID and LNID, computer simulation modelling, and extensive monitoring of district return flow. a) Block Studies Intensive monitoring of irrigation Block K5 in the BRID and Block J12 in the LNID has helped to track and quantify the water balance within irrigation blocks, and to understand factors affecting return flow. For discussion purposes, return flow can be divided into three primary components– operational spills, base flow and on-farm drainage. Operational spills usually occur as a result of sudden reductions in demand. Irrigation demands can change suddenly for numerous reasons, such as heavy rains, freezing temperatures, power failures, equipment breakdowns, end gun or corner arm shut-off on pivot systems, and set changes on side-roll systems. Increased return flow will continue until adjustments can be made to the system to restore the supply-demand balance. The need to flush canals and some reservoirs at start-up results in high return flow early in the irrigation season. During normal operations,base flow is required along canals to meet seepage and evaporation losses, to ensure the last users in the system have sufficient water to operate their pumps or turnouts, and to provide a margin of safety to accommodate sudden increases in demand. Base flows and operational spills are not diverted at the farm turnouts – they remain in the laterals to the tailouts. Data from the block studies indicate the average return flow at the tailout of the laterals was 0.07 cubic metres per second. The base flow component is believed to be substantially higher than the operational spills – perhaps about 0.06 cubic metres per second. The number of tailouts in a distribution system has a major effect on return flow. A branched system with numerous laterals and sub-laterals will have higher return flow than a linear system with fewer laterals. The number of tailouts can be reduced by replacing laterals with closed pipelines. On-farm drainage of surplus applications is usually small for sprinkler systems, but can make a significant contribution to return flow in areas where surface systems are common. Surface irrigation farmers in Block K5 returned about 40% of their total application to drains. The return flow from the irrigation block with a high percentage of surface irrigation was typically 75% to 100% higher than that of the block with only sprinkler systems. Data from the block studies indicate return flow is primarily a function of infrastructure characteristics, irrigation methods and district management. It appears to be independent of the gross diversion and irrigated area.

77 b) Recorded Return Flow Return flow occurs through numerous, often natural, drainage channels. It is often low and intermittent, and is sometimes combined with natural flow. Historically, a relatively small number of return flow channels have been monitored by Water Survey of Canada for the purposes of estimating total annual natural flow of the South Saskatchewan River, downstream of its confluence with the Red Deer River, for interprovincial apportionment purposes. Although the accuracy of return flow estimates so determined is considered to be sufficient for Prairie Provinces Water Board apportionment purposes, additional data are required by the districts to gain a better understanding of the amount of return flow, and its variability, components, and cause and effect relationships. Knowing these characteristics, it may be possible to identify measures to reduce return flow. Return flow is a significant component of the gross diversions and is a major consideration in the quest to make additional water available for expanding the irrigated areas within districts. In 1994, the EID began a major initiative to monitor flows returning to the Red Deer and Bow rivers. Since then, seven other districts have begun monitoring. In 1999, more than 80 return flow sites were monitored. Daily data for all stations were assembled and reviewed and apparent anomalies in the data were identified and discussed with district and AAFRD staff. Adjustments were made to address anomalies and fill in missing records. District staff estimated the percentage of total return flow that was not gauged. Six of the 13 districts conducted sufficient monitoring to permit reasonably accurate return flow estimates for all four years. Being the largest, these six districts contain more than 90% of the total irrigated area within all districts. Conclusions drawn from the results of monitoring in the six districts may be considered representative of all district irrigation. Note that the WID did not conduct return flow monitoring during the 1997 to 2000 period. However, Water Survey of Canada stations on the Rosebud River and Crowfoot Creek record about 80% of the return flow for the WID. The WID is therefore included as one of the six districts with reasonably accurate return flow estimates. The irrigated area, gross diversion and return flow for each district where monitoring was carried out are summarized in Table 17. The EID had the highest volume of return flow, averaging 174,011 cubic decametres for the four years. This amounts to about 35% of the total return flow for the six districts. The EID is the second largest district in terms of irrigated area. It has the longest length of conveyance works, and by far the highest area of surface irrigation, all of which contribute to high return flow. The EID showed a pronounced decrease in return flow during the four-year period. This could be attributed to an improved awareness of return flow and a concerted effort by district managers and operations staff to improve management of the infrastructure and increase irrigation efficiency. The EID began monitoring return flow in 1994, three years before other districts. Return flow expressed as a percentage of gross diversion varies substantially from district to district. It is highest in the WID, averaging 56.5%, and lowest in the SMRID, averaging 7.2%. Variations are a function of several factors combined, including the size of the district, water user density and the extent of infrastructure rehabilitation. Return flow, expressed as a percentage of gross diversion, tends to be higher in smaller districts with low densities of irrigation users (area irrigated per km of canal).

78 Table 17. Irrigation district actual irrigated areas, gross diversions (GD) and return flow. 1997 1998 Area Gross Return Flow Area Gross Return Flow District Irrigated Diversion Irrigated Diversion dam3 mm/ha %ofGD dam3 mm/ha %ofGD (ha) (dam3) (ha) (dam3) AID BRID 80,092 423,613 126,134 158 29.8% 80,210 374,447 127,844 158 34.1% EID 111,244 705,748 215,495 195 30.5% 111,269 787,590 186,862 168 23.7% LNID 58,706 238,774 40,651 70 17.0% 49,527 198,347 37,524 76 18.9% MID RID SMRID 138,502 574,811 42,551 30 7.4% 138,709 523,867 44,478 34 8.5% TID 30,791 142,570 29,007 94 20.3% 31,108 143,456 33,993 110 23.7% WID 25,273 143,999 87,491 347 60.8% 27,374 175,610 100,321 366 57.1%

1999 2000 Area Gross Return Flow Area Gross Return Flow District Irrigated Diversion Irrigated Diversion dam3 mm/ha %ofGD dam3 mm/ha %ofGD (ha) (dam3) (ha) (dam3) AID 757 4,229 3,387 448 78.8% BRID 80,155 368,229 109,064 137 29.6% 80,889 515,476 118,057 146 22.9% EID 112,394 526,443 149,873 134 28.5% 112,893 832,613 143,815 128 17.3% LNID 58,998 222,014 46,220 79 20.8% 61,514 303,189 49,320 79 16.3% MID 5,958 25,657 14,571 244 56.8% 6,243 37,202 13,138 210 35.3% RID 15,770 52,991 6,953 43 13.1% SMRID 144,068 507,614 39,006 27 7.7% 142,605 666,337 38,539 27 5.8% TID 32,038 129,774 40,958 128 31.6% 32,055 172,747 28,673 88 16.6% WID 20,653 109,054 84,883 411 77.8% 26,067 192,919 78,462 302 40.7%

Four-year Means 1991 Regulation Area Gross Area Licence District Return Flow Return Flow Irrigated Diversion Limit Volume dam3 mm/ha % of GDdam3 mm/ha % of GD (ha) (dam3) (ha) (dam3) AID 1,429 11,102 1,306 91 11.8% BRID 80,337 420,443119,298 148 28.4% 84,984 619,217 69,939 82 11.3% EID 111,950 713,099 174,011 155 24.4% 111,289 918,958 94,980 85 10.3% LID 1,930 14,802 1,764 91 11.9% LNID 57,187 240,58143,429 76 18.1% 67,583 391,020 35,019 52 9.0% MID 7,406 41,939 3,836 52 9.1% MVID 1,497 9,868 1,369 91 13.9% RCD 486 3,701 RID 18,818 99,914 9,745 52 9.8% SMRID 140,972 568,15841,143 30 7.2% 150,543 890,587 78,007 52 8.8% TID 31,499 147,13733,158 107 22.5% 33,265 194,893 17,232 52 8.8% UID 13,759 83,878 10,904 79 13.0% WID24,842 155,39587,789 354 56.5% 38,445 342,913 37,498 98 10.9% Totals 446,787 2,244,813 498,828 531,434 3,622,792 361,599 Weighted Mean 112 22.2% 67 10.0%

79 Canals with a high density of users have more predictable average demand conditions. As some users are ceasing operations, others are starting up. As rehabilitation progresses within the districts, lateral canals are replaced with pipelines and structures are automated. This increases response times to changes in demand and helps to reduce return flow. The number and location of storage reservoirs in the district can also be a factor in reducing return flow. Storage reservoirs reduce canal travel times, making possible more effective matching of supply and demand. Strategically located reservoirs also enable surplus canal flow to be stored for subsequent use downstream. Timely and accurate communications between water users and district operators are also important aspects of water management to minimize return flow within irrigation districts. The WID has little internal storage, long canals with low irrigation densities in some areas, a relatively low level of rehabilitation of their conveyance system, and a high traditional dependence on the district works for domestic and municipal water supplies. These factors tend to increase return flow. Rainfall runoff can also affect estimates of return flow for individual districts, particularly in high precipitation years and in districts that normally have higher amounts of natural precipitation, such as the WID. At the other end of the spectrum, the SMRID, the largest district, has a relatively high density of water users, a high percentage of pipe laterals, and a low percentage of flood irrigation. These characteristics tend to reduce return flow as a percentage of the gross diversion. The SMRID is also unique in its ability to recapture much of its unused irrigation deliveries in reservoirs and subsequently release it for downstream use. Unit return flow, expressed as millimetres per hectare irrigated, varies markedly from district to district in a ranking pattern similar to return flow expressed as a percentage of gross diversions (Table 17). The weighted-mean return flow used in the 1991Regulation was 10% of the licence volume. In five of the six districts, average unit return flow is substantially higher than assumed in establishing the 1991Regulation licence volumes. The exception is the SMRID, which returns less flow than was assumed in computing the licence volume. The monitored return flow within the block studies and within the districts was used to calibrate the IDM. For every scenario of water supply and demand, return flow can be provided as output from the model. The model includes a rainfall-runoff algorithm for determining the amount of natural flow likely to be in the return flow channels. Natural flow is not normally a significant component of total flow in most return flow channels in southern Alberta, although it can be significant for some districts in high precipitation years. Overall, a far more significant impact on return flow is the effect rainfall has on farm operations. Rainfall events often lead to shut down of on-farm irrigation systems and can substantially increase operational spills from district works.

80 c) PPWB Return Flow Estimates The Prairie Provinces Water Board (PPWB) estimates annual return flow contributions to river systems from the irrigation districts. The estimates for 1985 through 2000 are given in Table A-1 (Appendix). Some of the estimates are based on Water Survey of Canada provisional hydrometric data. For the WID, April data are excluded from Table A-1. Diversions to the WID do not normally begin until the last few days in April or early May. Including April in the return flow estimates results in unrealistically high return flow in years of high snow melt runoff, such as 1997. Table 18 compares return flow recorded by the districts and that estimated by the PPWB for 1997 to 2000. Estimates prepared by the PPWB include combined return flow from the three foothills districts (MVID, LID and AID) and from the MID, RID, SMRID and TID. The following observations can be made from Table 18. ! The PPWB estimates of return flow for the EID were consistently high, averaging 135% of recorded values for the four years. PPWB estimates for the BRID were consistently low, averaging 63% of recorded values for the four years. Where comparisons can be made for districts other than the BRID and EID, the PPWB estimates are generally within 10% of recorded values. ! PPWB estimates of total return flow for all districts for which comparisons can be made are remarkably consistent with recorded data (within 3%). The best year for comparison is 1999, when eight districts, representing about 98% of the total irrigated area, can be compared. PPWB estimates of the total return flow for the eight districts were 99.8% of the recorded return flow. In 1997, 1998 and 2000, only four districts, representing 58% of the irrigated area, can be compared. For these districts, the PPWB estimates of total return flow averaged 101.9% of the recorded values. From the comparison of recorded return flow and PPWB estimates, it would appear the PPWB estimates are a good representation of total return flow from all districts. Figure 30 shows the total return flow from all districts for the period 1985 to 2000, based on PPWB estimates, as well as the irrigated areas and gross diversions (AAFRD 2001/a). Observations from Figure 30 include the following. ! There has been a significant variation in year-to-year gross diversion, with major reductions in wet years and increases in dry years. The trend line shows a slight reduction in gross diversion during the 10-year period, in spite of an increase in the irrigated area. ! The irrigated area has steadily increased since 1985. In high precipitation years (1993 and 1995), the irrigated area drops significantly. ! The return flow has consistently been around 3000 600 600,000 cubic Gross Diversion (dam3 ) 2500 decametres per year for 500 the 16-year period. 2000 Return flow appears 400

1500 es in thousands) independent of irrigated Irrigated Area (ha)

area and gross diversion. Volume 3 1000 It is less variable and 300

does not seem to follow (dam in thousands) 500 Return Flow (dam3 ) the wet-year/dry-year Area (hectar 0 200 pattern that affect gross 1984 1989 1994 1999 diversions and irrigated area. Figure 30. Irrigation district return flows, gross diversions, and irrigated areas. (From PPWB and Water Survey of Canada data, some of which are provisional.)

81 Table 18. Comparisons between recorded return flow and PPWB estimates (PPWB 1995).1

1997 1998 Recorded PPWB Return FlowRecorded PPWB Return Flow District Return Flow %of Return Flow %of (dam3 ) (dam3 ) Recorded (dam3 ) (dam3 ) Recorded BRID 126,13477,32261.3% 127,884 76,451 59.8% EID 215,495271,340125.9% 186,862 250,195250,192 133.9% LNID 40,65135,60087.6% 37,524 39,905 106.3% MVID 2 2 LID MVLA2 MVLA 7,141 9,297 AID 7,141 MID SMP, MID3 SMP, MID3 RID 103,488 139,616 SMRID 42,551 44,478 TID 29,007 33,993 UID 9,002 5,482 WID4 87,49190,322103.2% 100,321 93,647 93.3% Sum5 469,771474,584101.0% 452,551 460,198 101.7%

1999 2000 Recorded PPWB Return FlowRecorded PPWB Return Flow District Return Flow %of Return Flow %of (dam3 ) (dam3 ) Recorded (dam3 ) (dam3 ) Recorded BRID 109,064 72,43966.4% 118,057 77,423 65.6% EID 149,873199,406133.1% 143,815 210,648 146.5% LNID 46,220 41,42889.6%49,320 35,500 72.0% MVID MVLA2 MVLA2 LID 10,644 22,516 AID 3,387 MID 14,571 13,138 SMP, MID3 SMP, MID3 RID 6,953 95,593 67,215 SMRID 39,00694.2% 38,539 TID 40,958 28,673 UID 13,419 26,678 WID4 84,88381,88596.5% 78,462 77,319 98.5% Sum5 491,528 490,751 99.8% 389,654 400,890 102.9%

1 Data obtained directly from Jim Chen, P.Eng., PPWB. Some return flow estimates may be based on Water Survey of Canada provisional data. 2 PPWB estimate labeled MVLA is total return flow for MVID, LID and AID. 3 PPWB estimate labeled SMP, MID is total return flow forSMRID, RID, TID and MID . 4 For the WID, April data are excluded from the estimates. 5 Sums for 1997, 1998 and 2000 include the BRID, EID, LNID and WID only. Sums for 1999 include the BRID, EID, LNID, MID, RID, SMRID, TID, and WID only.

82 d) Future Return Flow The block studies, district monitoring data and PPWB return flow estimates all suggest that return flow is primarily a function of district layout and infrastructure characteristics, on-farm irrigation methods and district operational characteristics. Return flow appears to be independent of the gross diversion and irrigated area. Reductions in return flow are possible through measures such as continued replacement of laterals with closed pipelines, new storage at strategic locations, automation of structures, increased irrigation densities, on-farm method shifts from surface irrigation to sprinklers, as well as district operations more focused on minimizing return flow. A future total return flow of 500,000 cubic decametres per year, or 13.8% of the licence volume, is achievable. This is a conservative value that could be used for planning purposes. Reductions beyond this amount are believed to be possible and should be set as a goal.

C. WATER DEMAND SUMMARY BASED ON KEY FINDINGS Following establishment of the 1991Regulation , AENV and AAFRD worked together to determine the volume of water that would be sufficient for irrigating the areas specified in each irrigation district. However, there was insufficient data to make reliable estimates with regard to on-farm irrigation management and efficiencies, district water losses and return flow. Many assumptions were necessary. Research conducted by the irrigation districts and AAFRD from 1996 to 2000 provides much-needed information. This has made it possible to improve the estimates of current and future water requirements, and to evaluate the estimates and assumptions made in 1991. Table 19 provides a simplified water demand analysis for the 13 irrigation districts. The analysis was prepared using a methodology and format similar to that used in 1991. For comparison purposes, three scenarios are presented: 1)TheRegulation limit. Estimates and assumptions inherent in determination of the proposed licence volume for theRegulation are given in Chapter II. Section C. The licence volume was based on 90th percentile irrigation demands for ultimate water demand conditions in the 13 districts. This scenario reflects the 1991 understanding of what the future might be for irrigation in Alberta. 2)The 1999 state of irrigation in Alberta. The results of research conducted from 1996 to 2000 were used to estimate water demands that reflect 1999 conditions within the irrigation districts. 3)Projected future conditions. Projections reflect trends and up-to-date judgements on where the irrigation industry appears to be headed in the next 10 to 20 years. The most significant difference in factors used to estimate on-farm requirements was the level of irrigation management considered in the three scenarios. The 1991Regulation licence volume was based on 100% of crop water requirements. From 1996 through 2000, irrigation water users met, on average, about 84% of the crop water requirement. Irrigation practitioners in Alberta believe that meeting, on average, 90% of the crop water requirement represents the upper limit of irrigation management in the future. This upper limit is based on the crops grown, and the cultural and harvesting practices in southern Alberta. Primarily as a result of the difference in the irrigation management factor, the projected future farm gate delivery requirement has been estimated to be about 430,000 cubic decametres less than estimated for the 1991Regulation .

83 Table 19. Simplified analysis of irrigation water demand for the 13 irrigation districts.

1991 1999 Projected Water Demand Component Regulation Conditions Future Licence Volume Conditions

On-farm Water Requirements Crop water requirement (90th percentile) 498 mm 507 mm Irrigation management factor(1996-2000 mean) 100% 84% 90% Water applied to crop 418 mm 456 mm Precipitation (10th percentile, growing season) 140 mm 140 mm Crop irrigation requirement 375 mm 278 mm 316 mm On-farm efficiency 75% 71% 75% Farm gate delivery requirement (90th percentile) 500 mm 392 mm 421 mm

Irrigation District Water Requirements

Case 1: Assume 531,434 hectares, as per 1991 Regulation

Farm gate delivery requirement 2,657,402 dam3 2,083,221 dam3 2,226,714 dam3 Seepage losses 471,759 dam3 89,753 dam3 54,000 dam3 Evaporation losses 132,021 dam3 142,016 dam3 140,000 dam3 Return flow 361,610 dam3 574,966 dam3 500,000 dam3 Gross diversion demand (90th percentile) 3,622,792 dam3 2,889,956 dam3 2,920,714 dam3

Case 2: Assume gross diversion of 3,622,792 dam3 , as perRegulation licence volume

Gross diversion 3,622,792 dam3 3,622,792 dam3 3,622,792 dam3

Seepage losses 471,759 dam3 89,753 dam3 54,000 dam3

Evaporation losses 132,021 dam3 142,016 dam3 140,000 dam3

Return flow 361,610 dam3 574,966 dam3 500,000 dam3

Farm gate delivery (90th percentile) 2,657,402 dam3 2,816,057 dam3 2,928,792 dam3

Farm gate delivery requirement (90th percentile) 500 mm 392 mm 421 mm

Total area that could be irrigated 1 531,434 ha 718,382 ha 695,675 ha

1 Based on theRegulation licence volume and water demand only. Water supply factors have not been considered.

84 With regard to irrigation district infrastructure, seepage losses appear to have been greatly over-estimated in 1991, evaporation losses were under-estimated (canal evaporation was not included in the computations), and return flow was under-estimated. All things considered, it is now estimated that the projected future 90th percentile demand for the 1991Regulation limit of 531,434 hectares (Table 4) is 2,920,714 cubic decametres. This is a reduction of 702,078 cubic decametres or about 19% of theRegulation licence volume of 3,622,792 cubic decametres. Assuming a 90th percentile gross diversion equal to theRegulation licence volume of 3,622,792 cubic decametres (Case 2), it is estimated about 695,675 hectares could be irrigated. This area is 164,241 hectares greater than the Regulation limit, an increase of almost 31%. This simplified analysis of water demand does not consider any aspects of water supply, including the availability of water in the source streams, the needs and water licence priorities of other users, capacity limitations on district infrastructure, and effects on individual irrigation blocks within the districts. All these factors are considered in the simulation modelling that is discussed in the following chapter of this report. The analysis in Table 19 serves to indicate that, considering all districts as a whole, a substantial amount of expansion beyond the 531,434 hectares in the 1991Regulation could be considered without a water allocation beyond the collectiveRegulation licence volume. This conclusion does not apply equally to all districts.

D. CONCLUSIONS The following conclusions have been drawn from the key research findings, based on four years of field research, data collection, and analysis.

The crop mix within the irrigation districts has changed during the past 10 years, and will likely continue to change in the future. It is projected that the future crop mix for irrigated agriculture will evolve toward an increased area of forage to support the expanding livestock industry, increased area of specialty crops to support value-added processing, and a decreased area of cereal grains. This will result, overall, in slightly higher water requirements than the current crop mix.

For the foreseeable future, an on-farm application efficiency of 75% is considered to be reasonable for planning purposes. The average, overall on-farm application efficiency within the irrigation districts in 1999 was estimated to be 71%. Significant gains in on-farm application efficiencies have been realized during the past four decades, as irrigation methods have changed and system technology has advanced. Additional gains should occur in the future.

Improved on-farm irrigation management will result in future water applications meeting 90% of optimum crop water requirements for the types of crops grown and the cultural practices in southern Alberta. It is estimated that farmers are irrigating to meet, on average, about 84% of the water required to obtain optimum crop yields. This level of irrigation management, or water application, has increased during the past 10 years, and is projected to continue to increase.

85 Seepage from district works will be reduced with continuing rehabilitation. Substantial progress has been made in rehabilitating irrigation district infrastructure and reducing seepage losses during the past 10 years. Seepage losses are estimated to be about 2.5% of licence volume. Seepage losses from canals appear to have been greatly overestimated in 1991. Continued reduction in seepage losses will occur in the future as more canals are rehabilitated.

In the future, canal evaporation may decrease slightly as more conveyance channels are replaced with pipelines. Reservoir evaporation losses are expected to increase if new reservoirs are developed within the districts. Canal and reservoir evaporation losses from the 1999 district infrastructure are estimated to be about 142,016 cubic decametres or almost 4% of the Regulation licence volume. Evaporation losses were slightly underestimated in the development of the 1991Regulation as canal evaporation was not included in the original computations.

Return flow is projected to decline by as much as 17% with continued rehabilitation of the water distribution infrastructure, improved on- farm and district water management, and potential development of offstream reservoirs. Field data recorded from 1997 to 2000 indicate return flow, expressed as a percentage of actual gross diversion, varies substantially from district to district – from a low of 7.2% to a high of 56.6%. In five of the six largest districts, average unit return flows are substantially higher than those assumed in establishing the 1991Regulation licence volumes. The exception is the SMRID, which returns less flow than was assumed in 1991. Annual return flow volumes from all irrigation districts have consistently totalled around 600,000 cubic decametres per year for the period 1985 through 2000. However, they are projected to decrease to 500,000 cubic decametres with continued water management efficiency gains. The addition of new storage facilities could not only increase the upstream supply of available water, but could also reduce return flow volume, as water is recaptured for further use.

A comparative water demand analysis for the 13 irrigation districts indicates the projected future gross diversion demands for the 1991 Regulation limits are significantly less than those estimated in 1991. Considering all districts as a whole and the gains in water management made through the 1990s, a substantial amount of expansion beyond the 1991Regulation limits could be considered within the Regulation licence volumes. The research program provided an updated and more scientifically sound database than was available in 1991 when theRegulation licence volumes were established. Using a methodology similar to that used in 1991, gross diversion demand for the 1991Regulation limit of 531,434 hectares was estimated to be about 19% less than originally estimated.

86 V.

Chapter Simulation Modelling Chapter V. Simulation Modelling

A. INTRODUCTION Computer simulation modelling of water demand and supply is an essential analytical technique for assessing water management options and optimizing the performance of complex water management systems. In the Irrigation Water Management Study, computer models were used to simulate various scenarios of development, management options and operational policies. Model output included water demands, water deliveries required to meet demands, stream flows, canal flows, losses, reservoir levels, irrigation deficits, and impacts of deficits on farm financial viability. The model output assists government and the irrigation districts to make informed decisions related to long-term planning. Modelling was conducted for stream flow and climatic conditions in the South Saskatchewan River Basin for the historical period, 1928 to 1995. The output represents what probably would have occurred had the level of irrigation development and the management scenario been in place during the period simulated. To facilitate modelling, the districts were divided into blocks of irrigated land primarily on the basis of infrastructure configuration and discrete inflow and outflow points. The characteristics of each block were determined based on inventories of variables such as crop types, irrigation methods, soil types, and water delivery systems. The number and sizes of the blocks within the districts are summarized in Table 20. There are 25 blocks within the districts supplied by diversions from the Bow River, and 26 blocks within the districts served by the Oldman River system. The blocks range in size from 756 hectares to 32,407 hectares. Some blocks are more susceptible to water supply shortages than others, depending to a large extent on the existence of supporting storage reservoirs. Irrigation water users in some blocks can also be impacted by irrigation deficits to a higher degree than those in other blocks, depending on factors such as crops grown and agro-climatic conditions.

Table 20. Irrigation blocks established for simulation modelling. Block Size (hectares)1 District No. of Blocks Smallest Block Largest Block Mean Bow River 8 1,182 27,097 10,014 Eastern 12 915 18,849 9,309 Western 5 1,905 12,625 5,941 All Bow Basin Districts 25 915 27,097 8,861 Aetna 1 756 756 756 Leavitt 1 1,871 1,871 1,871 Lethbridge Northern 4 5,832 32,407 14,835 Magrath 1 6,045 6,045 6,045 Mountain View 1 1,420 1,420 1,420 Raymond 1 16,741 16,741 16,741 St. Mary River 12 1,301 26,354 12,002 Taber 3 7,793 12,486 10,487 United 2 1,171 5,868 3,522 All Oldman Basin Districts 26 756 32,407 10,341 1 Based on 1999 irrigation areas.

89 B. MODELLING ASSUMPTIONS AND CALIBRATION Each of the three simulation models required certain assumptions and operating principles that are common for all scenarios analyzed. An understanding of these assumptions and principles is essential to the interpretation of model output. Each model was calibrated against monitored data to ensure the model was representative of actual field conditions. Assumptions and calibrations for each model are discussed below. 1. Irrigation District Model (IDM) a) IDM Assumptions i) Soil-Plant-Water Relationships ! Weather conditions (rainfall, temperature, etc.) for all fields modelled were taken from the nearest grid point in the agro-climatic database. ! Soil types, textures and water holding capacities were considered to be homogeneous for each field and throughout the root zone depth. ! Crop seeding dates were randomized across all fields within normal periods for seeding for each specific crop. ! Fall irrigation was assumed to take place each year on a randomized selection of 50% of the fields where soil moisture levels were at or below the irrigation threshold level. Fall irrigation was ruled out on certain fields that would not normally be irrigated in the fall, such as late harvest sugar beets.

ii) On-Farm Irrigation System Operations ! System coverage rates (hectares/day) were based on typical coverage rates for a quarter-section system. ! Irrigation system application efficiencies were set for each system type, at industry-accepted standard values for local conditions. ! Irrigation applications were controlled for daily soil moisture conditions and crop growth stage forindividual fields. Specific to each system type, irrigations were curtailed when precipitation events exceeded specified levels.

iii) Conveyance Works Operations ! Seepage and evaporation losses were based on the assumption that all canals were "checked" to run full for the entire irrigation season. ! Seepage from canals was determined based on capacity and soil texture specific to the location of each canal. Seepage from rehabilitated earth canals was considered to be significantly less than that from unrehabilitated earth canals. Seepage from pipelines and canals lined with materials other than clay was assumed to be zero. ! Canal start-up and shut-down dates are district specific and were assumed to be the same each year, regardless of weather variations. ! Operational spills due to unscheduled on-farm system down-times were assumed to be unavailable for downstream re-use. Therefore, the spills contributed to return flow. In reality, some of this water could be recaptured and re-used, thus slightly increasing the efficiency of water use beyond that computed from model output. ! Conveyance works capacities were assumed to be non-restrictive to meeting downstream demands for all scenarios.

90 b) IDM Calibration and Validation The IDM and its modules were first calibrated to ensure output results matched well with observed or recorded water demand or moisture supply situations in the field. Calibrations were derived for parameters such as: ! Total seasonal consumptive use for each crop type; ! Timing of crop water use, harvesting dates and "water on and off" dates; ! Carry-over and net residual soil moisture conditions through fall, winter and into early spring of each year; ! On-farm irrigation efficiencies and irrigation system water management as monitored in the intensive block studies; ! On-farm irrigation management by crop-type and method, as monitored in the field for several years; ! Return flow volumes scaled to match monitored flows in 1999; and ! Canal seepage rates based on soil texture categories and data from ponding tests. The validation process then compared modelling results against actual recorded water demand and consumption data. Model output comparisons were made for: ! Water diversions through the conveyance systems; ! Return flow quantities; ! Seasonal profiles of daily water demands; and ! Reservoir levels throughout the irrigation season. The validation exercise involved examining the three-year period, 1987 through 1989, within the SMRID, TID, RID and MID. In general, modelling results were within 1% to 2% of the actual recorded data. Additionally, the IDM was calibrated and validated for special applications within the EID. Model results compared well with the results of extensive multi-year water audits the EID conducted through the late 1990s.

2. Water Resources Management Model (WRMM) The WRMM (and its sub-models) determined the relationship between water supply and demand for the entire SSRB. Model runs included all major storage reservoirs, diversions, water uses, and apportionment commitments. a) WRMM Assumptions ! The rights and priorities of existing licences and licence-holders were recognized and adhered to. Licence priorities were modelled for major water allocations, such as the irrigation districts. Private projects were lumped together by river reach and modelled as one demand, with a priority that reflected the average priority of the individual projects. ! Alberta’s interprovincial apportionment commitments were respected. ! An allowance was made for future municipal and industrial water demands. ! All established instream flow objectives were considered.

91 ! Private irrigation demands included the existing licensed area and reservations for new irrigation blocks, as defined in the 1991 South Saskatchewan Basin Water Allocation Regulation. ! No new provincial flow regulation works were considered beyond the existing and committed works. ! For the Base Case Scenario, existing capacities were used for headworks infrastructure owned and operated by the province. For future scenarios, planned capacities of headworks infrastructure were used as limits for water deliveries.

b) WRMM Calibration Integration and joint use of the IDM and WRMM were tested in calibration runs simulating the St. Mary Project for 1988 and the EID for 1994 to 1999. Adjustments were made to variable parameter settings until modelled gross diversions and return flows for the districts matched recorded data reasonably accurately. Insufficient historical data from other irrigation blocks precluded calibration in other districts. Bow Basin Districts WID-W 3. Farm Financial Impact and Risk Model (FFIRM) WID-E / EID-N The FFIRM was used to determine the impacts of irrigation deficits in four BRID / EID-S selected scenarios on typical farm enterprises in various regions within the irrigation areas. Two additional scenarios were analysed using the FFIRM to Oldman Basin Districts verify certain conclusions drawn from model output. UID / MID a) FFIRM Approach LNID / RID / SMRID-W The climate of southern Alberta tends to influence the size of irrigation TID / SMRID-E farms and the types of crops grown. In cooler regions with higher natural precipitation, irrigation farms are generally smaller and producers tend to irrigate primarily forage and cereal crops. In warmer, more arid regions, crop mixes are more diverse and include specialty crops such as corn, sugar beets and potatoes. Six climate and crop regions were identified for Strathmore analysis using FFIRM(Figure 31) . Within each region, two to four typical types of farm enterprises, represented by crop and irrigation methods mixes, were considered in the analysis. The typical crop mixes were developed Brooks from crop statistics for 1999. The typical on-farm methods and crop mixes for each region used in the FFIRM analysis are provided in Figures 32 to 37 and in Table A-2 in the appendix. Medicine Hat FFIRM consists of two main components– a water application optimization component, and a farm financial simulation component. In the optimization component, the water demand and supply conditions for each year, derived from the IDM and WRMM, were reviewed to Lethbridge determine the optimal allocation of water among the two to four fields on the representative farms. In years when a water shortage occurred, the optimization routine allocated water on a priority basis to the crops that maximized financial returns to the farm.

Figure 31. Climate and crop regions applied in FFIRM analyses.

92 Surface - Undeveloped Surface - Developed Sprinkler - Wheel-move Sprinkler - Pivot High Pressure Sprinkler - Pivot Low Pressure

Methods and systems mix (% of area) Crop mix for farm enterprise type (% of area)

U1 - Grain and forage mix 36 Hard red Alfalfa 9 spring wheat 2 cut Barley Canola 30% 25% 25% 20% 22 14 U2 - Forage Mix 19 Alfalfa Tame 2 cut grass Barley 40% 30% 30%

Figure 32. Mix of on-farm irrigation systems and crops for two farm enterprise types in the UID - MID area.

L1 - Grain and oilseed mix Durum Soft Barley wheat wheat Canola 40% 20% 20% 20% 38 L2 - Sugar beet mix 23 Alfalfa Soft Sugar 3 cut Barley wheat beets 9 30% 30% 20% 20% 4 26 L3 - Grain and forage mix Alfalfa Silage Soft 3 cut barley wheat Barley 25% 25% 25% 25%

L4 - Forage mix Alfalfa Tame Silage Durum 3 cut grass barley wheat 30% 30% 20% 20%

Figure 33. Mix of on-farm irrigation systems and crops for four farm enterprise types in the LNID, RID, and SMRID-W (Lethbridge area).

93 Surface - Undeveloped Surface - Developed Sprinkler - Wheel-move Crop mix for farm enterprise type (% of area) Sprinkler - Pivot High Pressure Sprinkler - Pivot Low Pressure B1 - Grain and oilseed mix Durum Soft Barley wheat wheat Canola Methods and systems mix (% of area) 40% 20% 20% 20% B2 - Sugar beet mix Alfalfa Sugar Dry 11 3 cut Barley beets beans 30% 30% 20% 20% 28 B3 - Potato mix 52 Soft 7 2 wheat Barley Canola Potato 25% 25% 25% 25%

B4 - Forge mix Alfalfa Silage Durum Tame 3 cut barley wheat grass 35% 30% 20% 15%

Figure 34. Mix of on-farm irrigation systems and crops for four farm enterprise types in the TID and SMRID-E (Burdett area).

E1 - Grain and oilseed mix Durum Soft Barley wheat wheat Canola 40% 20% 20% 20% 33 E2 - Sugar beet mix 35 Alfalfa Soft Sugar 3 cut Barley wheat beets 12 30% 30% 20% 20% 3 17 E3 - Potato mix Soft wheat Barley Canola Potato 25% 25% 25% 25%

E4 - Forage mix Alfalfa Silage Durum Tame 3 cut barley wheat grass 35% 30% 20% 15% Figure 35. Mix of on-farm irrigation systems and crops for four farm enterprise types in the EID-S and BRID (Enchant area).

94 Surface - Undeveloped Surface - Developed Sprinkler - Wheel-move Sprinkler - Pivot High Pressure Sprinkler - Pivot Low Pressure

Methods and systems mix (% of area) Crop mix for farm enterprise type (% of area)

S1- Grain and forage mix Hard red Alfalfa spring wheat 2 cut Barley Canola 24 30% 25% 25% 20% 49 4 S2 - Forage mix Alfalfa Tame 14 2 cut grass Barley 9 40% 30% 30%

Figure 36. Mix of on-farm irrigation systems and crops for two farm enterprise types in the WID-W (Strathmore area).

R1- Grain and oilseed mix Durum Soft Barley wheat wheat Canola 40% 20% 20% 20% 33 R2 - Grain and forage mix 35 Alfalfa Silage Soft 12 3 cut barley wheat Barley 25% 25% 25% 25% 3 17 R3 - Forage mix Alfalfa Tame Silage Durum 3 cut grass barley wheat 30% 30% 20% 20%

Figure 37. Mix of on-farm irrigation systems and crops for three farm enterprise types in the WID-E and EID-N (Rosemary area).

95 The second component simulated the farm financial characteristics during the entire 68-year period, 1928 to 1995. The financial component tracked the costs and returns related to each individual field, as well as all farm financial accounts relating to depreciation, capital purchases and farm loans. Three key performance indicators– net farm income (NFI), debt and equity levels– for the 68-year period are illustrated in Figure 38 for a grains and oilseed farm. The annual NFI was more often negative than positive. Consequently, the net worth of the farm generally declined and the debt increased. As the debt increased, interest costs increased, putting further downward pressure on NFI. Figure 39 shows the same information for a farm that includes a specialty crop within the mix. Annual NFI was highly variable, but usually positive. As a result, debt was eliminated with time, and the net worth of the farm continually increased. b) FFIRM Assumptions ! Irrigation Methods Mix – Field inventory data for 1999 indicated the mix of on-farm application methods varied within the six regions. The methods affected on-farm efficiencies, capital and operating costs, and annual depreciation costs.

120 6 80 4 40 2 0 0 (40) (2)

(80) (4) (millions of $)

Net Worth or Debt

(thousands of $) (120) (6) Annual Net Farm Income 1925 35 45 55 65 75 85 95

Net Farm Income Net Worth Debt

Figure 38. Financial performance of a grains and oilseeds farm.

120 6 80 4 40 2 0 0 (40) (2)

(80) (millions of $) (thousands of $) (4)

Net Worth or Debt (120) (6)

Annual Net Farm Income 1925 35 45 55 65 75 85 95 Net Farm Income Net Worth Debt

Figure 39. Financial performance of a sugar beet farm.

96 ! Farm Debt Levels – Three different opening debt levels were assessed for each representative farm. Debt level is an important factor in determining the risk of financial insolvency as a result of water supply shortages. Producers with higher debt levels are less able to withstand irrigation deficits. The opening debt to asset ratio for the Base Case was set at 15%. The medium and high opening debt to asset ratios were set at 35% and 50%, respectively. ! Crop Prices – Crop prices used in the financial simulations were based on the average prices experienced for the 10-year period from 1990 to 1999, expressed in 1999 dollars. These prices represent average price expectations for the future. Superimposed on these average prices were the actual variability of crop prices demonstrated during the 25-year period from 1975 to 1999. ! Cost of Production –V ariable n on-irrigation costs were based primarily on cost-of-production analyses conducted by AAFRD for irrigation farms in 1999 and 2000, as well as cost-of-production budget projections for Assessing the 2001. Production costs included management and labour. Risk of Insolvency – ! Set Crop Mixes – The producer was assumed to have established the crop Two criteria are used to mix and crop inputs for the representative farm at the first of the year, assess the risk of insolvency: before water shortage information becomes available. An indication of the impact of changing crop mixes in anticipation of water shortages can be ! Debt to asset ratio is the assessed in a general sense by comparing financial returns across ratio of total farm debt to representative farm types. total farm assets. Total farm debt is the amount ! Farm Revenue – The model estimated only the revenue accruing from owing on all farm loans, crop production. It did not provide any revenue from sources such as crop plus additional interest insurance or government farm income assistance programs. owed on overdue payments. Total farm c) FFIRM Calibration and Validation assets is cash on hand plus The financial analysis results are a product of a wide range of input depreciated value of all variables, including farm machinery complements, yield formulas, historical buildings and equipment, price data and cost-of-production profiles. Farm simulation runs were plus value of farmland. conducted to assess the performance of the FFIRM. Based on this preliminary assessment, various adjustments were made to the input variables, particularly ! Current ratio is the ratio of with respect to some yield formulas and cost-of-production profiles. current assets to current liabilities, where assets is d) FFIRM Evaluation Criteria cash on hand, and liabilities is the year’s The FFIRM results can be used to compare the benefits and costs, at the required payments on all farm level, of the Base Case Scenario (S1) to the other scenarios. The model farm loans. generated a wide variety of farm financial measures. For details on the financial simulation model and measures of financial viability, refer to the technical reports in Volume 5. In this Summary Report, three financial measures are presented. ! Risk of Insolvency - The model estimates the likelihood representative farms would experience financial difficulties to the extent of facing insolvency. For the purposes of this analysis, the debt to asset ratio and the current ratio were used in tandem to evaluate the solvency/insolvency condition. The model farm was considered to be insolvent when the debt to asset ratio exceeded 0.6 (more than $0.60 of total debt per dollar of total assets) and the current ratio fell below 1.0 (less than $1 in current assets per dollar of current liabilities) at the same time.

97 ! Net Farm Income - NFI is total revenue minus farm cash costs (excluding capital replacement costs) and minus depreciation. It is an indicator of the average profitability of the representative farms under different scenarios. ! Probability of Negative Net Farm Income - A higher risk of negative annual NFI increases the likelihood of farm financial difficulties, primarily through increased borrowing needs, and the risk of reduced credit ratings and higher loan rates. A new water supply scenario may indicate an increase in average NFI during the 68-year period. However, it is also possible there is an associated increase in income variability.

C. THE SCENARIOS Simulation modelling was conducted to determine the impacts of various Irrigation Area - on-farm and district water management demand variables on the performance of For the purposes of this the irrigation system, as well as the ability of the river basins to meet the demand. study, irrigation area refers Modelling scenarios were formulated considering 1999 conditions, projected to the area developed or future conditions and various future management options. Variables considered in equipped to be irrigated. It the scenarios included: is the area modelled in the ! Irrigation expansion; IDM as having the potential ! to generate an irrigation Shifts in crop mixes; demand for a given ! Shifts in the mix on-farm irrigation methods; scenario. ! Increased irrigation applications to near optimum crop water requirements; ! On-farm system operating and application efficiency improvements; and ! Improved district water supply operations and reduced return flows. System performance was evaluated based on: ! Crop irrigation requirements; ! On-farm losses; ! Irrigation district system losses; ! Return flows; ! Water supply deficits; and ! Economic impacts on farm enterprises. Each planning scenario consisted of a set of assumptions, based on crop mix, on-farm equipment mix, on-farm management capability, distribution system efficiency, and irrigation area within the districts. Output identified the frequency and magnitude of deficits in delivery of the ideal requirements. Ten scenarios, representing a variety of irrigation areas, crop mixes and levels of water management, both on-farm and within the districts, were formulated and modelled (Table 21). The variables considered were as follows. Column (1): Irrigation Area – The area actually equipped to be irrigated in the districts in 1999 was used to represent the irrigation area in Scenario S1. In Scenarios S2 and S3, the 1991Regulation limits of irrigation expansion were used for all districts except the EID. The EID negotiated an adjustment to their expansion limit from 111,293 hectares to 115,740 hectares. This adjustment was approved by Irrigation Council and is the irrigation area used in Scenarios S2 and S3, to give a total irrigation area for all districts, except Ross Creek, of 535,400 hectares. Scenarios S4, S5, S6, S8 and S9 consider a 10% expansion above the Regulation limits to 588,940 hectares. Scenarios S7 and S10 consider a 20% expansion above the limits to 642,480 hectares.

98 Regulation

Base Case

limits, with projected improvements limits, with a projected shift in crop limits, with a projected shift in on- limits, with projected improvements limits, with improved on-farm and limits, with shifts in on-farm system limits, with shifts in on-farm system

Regulation Regulation Regulation Regulation Regulation Regulation Regulation

Regulation

Primary Purpose

Determine water demand, supply deficits and risks to producers under 1999 irrigation conditions (

Determine impacts on demands and deficits with expansion to the 1991Determine risks to producers of expansion to the 1991 limits, under 1999 irrigation demand and management conditions. limits, with projected improvements in on-farm and district Determine water demand and supply deficits with 10% expansion management and near optimum crop water management. beyond the 1991 Determine water demand and supply deficits with 10% expansion in on-farm management conditions. beyond the 1991 Determine water demand and supply deficits with 10% expansion mix. beyond the 1991 Determine water demand and supply deficits with 20% expansion farm irrigation system mix. beyond the 1991 Determine impacts and risks to producers with 10% expansion in on-farm management conditions. beyond the 1991 Determine water demand and supply deficits with 10% expansion district management and near optimum crop water management. beyond the 1991 Determine water demand and supply deficits with 20% expansion and crop mixes, and near optimum crop water management. beyond the 1991 and crop mixes, and near optimum crop water management.

(6)

1999

1999 1999 1999 1999 1999

Flow

Mgmt.

Return

District

Improved

Improved Improved Improved

(5)

Crop

80% of 80% of 90% of 80% of 90% of 80% of 80% of 90% of 80% of 90% of

Water

Mgmt.

optimum optimum optimum optimum optimum optimum optimum optimum optimum optimum

WRMM. Highlighted scenarios are the primary focus of extensive analysis.

(4)

1999 1999

Mgmt.

System

On-farm

Improved

Improved Improved Improved

Improving Improving Improving Improving

(3)

Mix

System

On-farm

(2)

Mix

1999 1999 1999 1999 1999 1999 1999 Future 1999 1999 1999 1999 1999 1999

Crop

Future 1999 Future Future Future Future

(1)

Area

1999

plus 10% plus 10% plus 10% plus 20% plus 20% plus 10% plus 10%

Irrigation

1991 limit 1991 limit 1991 limit 1991 limit 1991 limit 1991 limit 1991 limit 1991 limit 1991 limit

Scenario Number

S1.

S2. S3. S4.

S5. S6. S7. S8. S9. S10.

All scenarios were analysed using output from the IDM and ‘1999’ = the weighted average in 1999.

Table 21. Summary description of the various scenarios developed and analysed.

99 The model runs assume the entire area in each scenario is irrigated every year. In practice, a portion of the land on the district assessment rolls is not irrigated. The percentage of unirrigated land varies from district to district and from year to year, depending on agro-climatic conditions, crop rotations, market conditions, and other factors. Column (2): Crop Mix – The crop mix used for Scenarios S1 to S4, S6 and S8 is based on a crop mix distribution as grown in 1999 (Table 22). The future crop mix for Scenarios S5, S9 and S10 considered the trend toward an increased area of forage to support the livestock industry, an increased area of specialty crops to support value-added processing, and a reduced area of cereal grains. Column (3): On-farm System Mix – The on-farm system mix includes irrigation systems (surface irrigation vs sprinkler irrigation) as well as types of on-farm equipment, all of which have a bearing on application efficiency. The Base Case system mix used in Scenarios S1 to S5, S7 and S8 was taken from the methods and systems used in 1999 (Table 22). The future system mix considered a shift from surface irrigation to sprinkler irrigation, and a shift toward low pressure centre pivot systems. Column (4): On-farm System Management – The on-farm application efficiency is dependent on both the method practiced or type of system used, and on how well irrigation farmers manage water applications. Each system type has a range of efficiencies in delivering water to the soil root zone. The place where any individual water user’s system falls within the range is a function of system design, soil, topographic and climatic characteristics, as well as management style and skill. A detailed 1999 inventory of on-farm systems throughout the irrigation districts indicated a potential weighted-average on-farm application efficiency of approximately 71% (Table 23). However, for modelling Scenarios S1 and S2, the on-farm system management level setting for 1999 conditions placed respective system application efficiencies at slightly less than their respective averages (i.e. , a weighted-average of approximately 68%). In Scenarios S4, S5 and S7, system management levels were assumed to be improving, with system application efficiencies modelled at an overall weighted- average efficiency of nearly 70%. For Scenario S6, the system management level was once again modelled asimproving , but as a result of the projected shift in system mix to future conditions, the weighted-average system application efficiency applied was nearly 77%. For Scenarios S3 and S8, system management was projected to beimproved , resulting in a weighted-average application efficiency of 71% for all districts. Scenarios S9 and S10 also reflect improved system management for all districts, but when combined with a projected shift in system mix, they provide results based on a weighted-average application efficiency of nearly 78%. Column (5): Crop Water Management – Monitoring from 1996 to 2000 indicated that irrigated crops receive, on average, about 84% of the total moisture required for optimal yields. (Total crop moisture includes soil moisture, growing season precipitation and irrigation applications.) This level of irrigation management has increased during the past 10 years, and is projected to increase to as high as 90% of optimum, on average. An overall average application of 80% of optimum was used to represent 1999 crop water management in Scenarios S1, S2 and S4 to S7. Scenarios S3, S8, S9 and S10, used an application of 90% of optimum.

100 Table 22. Base Case (1999) and projected crop mixes. Future Crop Mix Crop Type Base Case Crop Mix Adjustment Mix Factor Cereals 33.4% balance* 21.8% Forages - Pasture 8.7% 0.80 7.0%

- Other Forages 29.9% 1.20 35.8% Oil Seeds 9.5% 1.10 10.5% Specialty Crops - Potatoes 2.4% 2.00 4.9%

- Sugar beets 3.2% 1.25 4.0%

- Fresh Vegetables 0.8% 3.00 2.4% - Pulse 4.4% 1.35 5.9% - Other Specialty Crops 7.7% 1.00 7.7% * Balance refers to the percentage of irrigation area converted from cereals to other crops.

Table 23. On-farm irrigation methods/system mixes and application efficiencies. On-farm Methods and Systems (%) On-farm Application Efficiency (%) 1999 Future Mix Efficiency 1999 Future Method or System Range Efficiency Efficiency Mix Adjustment Mix

Surface - Undeveloped 5.6 0.25 1.4 20-45 30 30

- Developed Uncontrolled 7.8 0.50 3.6 50 - 75 60 63

- Developed Controlled 3.0 1.50 4.4 70 - 85 75 80

Sprinkler - Hand Move and 0.8 0.50 0.4 55-85 65 70 Solid Set

Sprinkler - 2 Lateral Wheel 21.7 0.30 6.5 65-80 67 70

Sprinkler - 4 Lateral Wheel 8.2 1.20 9.8 65-80 70 72

Sprinkler - HP Pivot, Linear1 18.10.25 4.5 70 - 85 74 76

Sprinkler - LP Pivot, Linear1 34.6balance2 69.3 75 - 90 80 82

Volume Gun, Traveller, etc. 0.2 0.50 0.1 55 - 75 63 66

Micro-spray or Drip 0.01 1.50 0.01 70 - 95 82 87

Weighted-Average 71 78

1 HP = high pressure; LP = low pressure. 2 Balance refers to the percentage of irrigation area converted from other systems to low pressure (LP) pivot or linear systems.

101 Column (6): District Return Flow Management – The district return flow management variable is a function of several factors, including the extent to which district works have been rehabilitated, the extent of automation of structures, the location and number of balancing and supply reservoirs, district irrigation area density, monitoring, communication between operating staff and water users, and staff training. As district water management improves, return flow generally decreases, although there may be circumstances that make significant reductions in return flow more difficult to achieve in some districts than in others. Return flow is comprised of operational spills, on-farm system downtime losses, drainage from irrigated fields, and base flow. Down-time losses and runoff from irrigated fields are primarily a function of on-farm irrigation methods and on- farm management. These two components of return flow were computed directly in the IDM based on the method mix and the level of on-farm water management assumed. The base flow component is the amount of flow required in canals and open pipelines (as opposed to pressure pipelines or closed systems) to keep the conveyance system hydraulically primed and to ensure the last user on the system has an adequate and accessible water supply. The amount of base flow in the districts is largely a function of district infrastructure and operations management. The 1999 base flow was determined in the model through a calibration process, by adjusting the base flow component until modelled return flow matched well with recorded return flow. Future return flows were estimated based on the expected mix of methods, systems and reduced base flows that reflect an improved level of district return flow management. The degree of adjustment in base flow was based on an understanding of unique circumstances within each district, the levels of return flow reduction already accomplished in some districts, and expert judgement.

Modelling of each scenario involved three steps. The IDM was used to determine daily crop water requirements, farm gate delivery requirements, losses within the district works, return flow and total diversion requirements for the 51 irrigation blocks. The WRMM was used to determine the extent to which the total diversion requirements could be met, considering the natural flow regime of the South Saskatchewan River system, the capability of the water management infrastructure in the basin to regulate flows, and all other consumptive and instream water needs in the basin, according to their respective licensed priorities. Output from the WRMM runs was used to determine deficits in meeting total diversion requirements for each block and for each time step in the modelling period. FFIRM was used to determine the impacts of irrigation deficits from four selected scenarios on typical farm enterprises in various regions within the irrigation areas. Results of the simulation modelling are presented and discussed in the following chapter.

102 D. CONCLUSIONS The following key conclusions have been derived from irrigation water demand and financial impact modelling.

The simulation models developed in this study are excellent tools for evaluating the effects of changing water management variables on water demand and supply within the irrigation districts.

Irrigation systems are complex and variable. In order to effectively and accurately project the effect that any one change or combination of changes in variables may have on water demand and supply, extensive computations are required. The computer models developed in this study were proven to mathematically represent the demand and supply of water for various climatic and irrigation conditions in southern Alberta.

The models replicate actual water demand and supply conditions in southern Alberta to within approximately 1% of recorded data.

In order to verify that the irrigation demand and water supply models were capable of adequately representing actual conditions, the models were run for a series of years with well documented and extensive irrigation demands within the RID, SMRID and TID. Results showed that modelled irrigation diversions and reservoir storage changes were within approximately 1% of actual recorded data. Similar results were achieved using multi-year water auditing data from the EID.

A detailed 1999 crop and irrigation inventory identified the crop varieties and irrigation systems for all irrigation fields in each irrigation district. This database is essential for irrigation districts to assess water demands and to plan future irrigation development.

The inventory quantified the location and areal extent of 56 different crops grown and 18 different types of irrigation systems being used within the irrigation districts. This comprehensive database enhanced the accuracy of the irrigation water demand assessments. Inventory data also allowed the delineation of six climate and crop regions to support the characterization and financial modelling of various farm enterprise types within those regions. This database provides an excellent basis for further modelling and analysis by the irrigation districts.

103 VI

Chapter Potential for Irrigation Expansion Chapter VI. Potential for Irrigation Expansion

This chapter discusses the water supply and demand relationship for each of the two major source basins, the Bow River Basin and the Oldman River Basin. The Bow River Basin includes three irrigation districts (BRID, EID and WID); the Oldman River Basin includes nine districts (AID, LID, LNID, MID, MVID, RID, SMRID, TID and UID). All districts in the Oldman River Basin, except the LNID, rely on the Waterton-Belly-St. Mary River system for their water supplies. The Oldman River is the source stream for the LNID. Ross Creek Irrigation District, which is part of the South Saskatchewan River Sub-basin, was not included in this analysis. The water supply and demand relationship is unique for each individual district. It is dependent on numerous factors, including the hydrology of the source stream, capacities and locations of headworks and district storage, climate, on-farm and district efficiencies, and return flow. A detailed assessment of each individual district is essential for making district-specific decisions, but such an assessment is beyond the scope of this report. In this chapter, the irrigation blocks are combined into districts, and districts into those supplied from the Bow River and those supplied from the Oldman River systems. Data averages presented for each basin are weighted by the irrigated area within each block. Irrigation deficits are presented in terms of the weighted frequency for various magnitudes of deficits. More detailed data, at the block and district level, are available to address specific issues and enquiries. Ten scenarios and three modelling components provided an extensive amount of data that could be analysed. The results of each of the three modelling components, Irrigation District Model (IDM), Water Resources Management Model (WRMM), and Farm Financial Impact and Risk Model (FFIRM), will be examined separately, followed by a discussion of the integrated findings of all three modelling components for four selected scenarios.

A. ANALYSIS OF IDM IRRIGATION DEMAND DATA The IDM determined the character of water demands for each scenario. Output from the IDM runs provides a breakdown of the water demand components. ! Crop irrigation requirement – the portion of the diverted irrigation water that is required for crop use. ! On-farm losses – the irrigation water lost in the on-farm application process due to evaporation, run-off and deep percolation. ! District infrastructure losses – irrigation water lost through district canal seepage and evaporation, reservoir evaporation, and tail-water flows that are not returned to a river system as return flow. ! Return flow – the portion of diverted water that passes through the irrigation district, due to on-farm system downtime, re-captured field run-off, and conveyance works base flow, and is then returned to a creek or river system. ! Gross diversion demand – the total water demand for the irrigation system at a primary river or reservoir diversion location. It is the sum of the above four components. The crop irrigation requirement, on-farm losses and district infrastructure losses are components of the consumptive use of the irrigation system. The return flow component is part of the overall gross diversion requirement, but is returned to a river system and is available for downstream consumptive or instream use.

107 1. Comparisons with 1991Regulation Licence Volumes Figure 40 provides a comparison of the irrigation district licensing volumes determined for administering the 1991Regulation with current and future irrigation water demands. The demands shown are the 90th percentile weighted- mean values for all 12 districts, consistent with the quantification process used in developing the licensing volumes in 1991 (see Table 4 and associated text). The comparison is based on the following six conditions. ! 1990 refers to 90th percentile irrigation district water uses as they were understood to be in 1990. These water uses served as a basis for developing the 1991Regulation licence volumes. ! Reg.(Regulation ) Limit shows the 90th percentile irrigation demand determined for administering the 1991Regulation . The volumes were determined by adjusting the 1990 uses to reflect improvements in efficiencies and management. ! S1 refers to the modelled demand for the 1999 actually-irrigated area (or area equipped to be irrigated) using current crop mixes, irrigation efficiencies and management practices. The graphics and discussion ! S2 refers to the modelled demand for the 1991Regulation irrigation area of water demands and limits, with current (1999) crop mixes, on-farm and district efficiencies, and deficits are expressed as crop water application levels at 80% of optimum. depths of water per unit ! S9 refers to the modelled demand for the 10% expansion beyond the area of irrigation, using Regulation limits, with future crop mixes, improved irrigation efficiencies, mm/ha, or mm. and water application levels at 90% of optimum. Millimetres per hectare can ! S10 refers to the modelled demand for the 20% expansion beyond the be converted to a volume Regulation limits, with future crop mixes, improved irrigation efficiencies, unit, cubic decametres and water application levels at 90% of optimum. (dam3 ), by multiplying mm/ha by the irrigated area Base Case (S1) and future (S2, S9, S10) gross diversion demands, expressed in ha, divided by 100 in millimetres per irrigated unit area (Figure 40a), are considerably less than (dam3 =mm/ha x ha/100). those used in determining the licence volumes for administering the 1991 Regulation. This is a result of significantly decreased crop water applications, reduced seepage losses and increased on-farm efficiencies. For the Reg. Limit Scenario, it was assumed 100% of the optimum crop water requirement would be applied. Current applications (S1 and S2) average about 80% of optimum. Future applications (S9 and S10) are expected to increase to 90% of optimum. Reduced

800 5 40a. Depth Basis 700 40b. Volume Basis 4 600

inmillions) 500 3 3 400 300 2 200 1

Water Demand (mm) 100

0 Water Demand (dam 0 1990Reg. LimitS1S2S9S10 1990 Reg. Limit S1 S2 S9 S10 Return Flow Farm Losses Infrastructure Losses Crop Irrigation Requirement Figure 40.Regulation licence allocation and projected water demands for selected scenarios. (All values represent 90th percentile weighted-means for all districts.)

108 current and future seepage losses are due to canal rehabilitation, extensive replacement of canals by pipelines, and over-estimation of seepage losses due to a lack of reliable data in 1991. Increased on-farm efficiencies are due to continual upgrading of irrigation methods and systems, and improved on-farm management. Current and future return flows are as high or higher than those assumed for the 1991Regulation . IDM output shows that, with improved efficiencies and crop water application at 90%(Scenario S10) , an irrigation area 20% larger than the 1991 Regulation limits could be irrigated with less water than proposed for administering the 1991 Regulation (Figure 40b). This conclusion does not apply equally to all districts. Nor does it consider any aspects of water supply and the needs and priorities of other water users. All districts in the Oldman Basin have licence water allocations equal to theRegulation licence volumes developed in 1991. In the Bow Basin, the WID and BRID do not have licenced allocations for those volumes, though both districts have applied for additional allocations. The EID has a licence volume greater than the volume determined in 1991. However, a portion of their allocation is for diversions during the non-irrigation season. The EID has applied for an amendment to their licence to better reflect irrigation needs. 2. Basin Specific Variations Figure 41 shows individual scenarioweighted-mean demand , in depth of water per hectare, for the Bow and Oldman basins. On average, the irrigation districts served from the Oldman Basin require 25% to 30% less water per unit of irrigation area than the districts served by the Bow River. In both basins, the crop irrigation requirement and on-farm losses are approximately equal. However, infrastructure losses and return flows are substantially higher in the Bow Basin. Evaporation losses from district reservoirs in the Bow Basin are almost double those of the Oldman Basin, due to almost double the surface area. Return flow in the Bow Basin is 200% to 250% greater than in the Oldman Basin districts. The reasons for increased return flow in the Bow Basin are district-specific and include lower- density districts (as measured in the ratio of irrigated area to length of conveyance works), the greater percentage of surface irrigation, and the lack of strategically located storage reservoirs to capture unused irrigation water deliveries. The IDM water demand output for all scenarios is summarized in Table A-3 in the appendix.

600 600 Bow Basin Oldman Basin 500 500

400 400

300 300

200 200

100 100

Water Demand (mm)

Water Demand (mm) 0 0 S1S2S3S4S5S6S7S8S9S10 S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 Return Flow On-Farm Losses Infrastructure Losses Crop Irrigation Requirement Figure 41. Modelled weighted-mean irrigation water demands for 10 water management scenarios.

109 600

400 Return Flow Infrastructure Losses On-farm Losses Crop Irrigation Requirement 200

(mm)

Water Demand

0 AID/LID BRID EID LNID MID MVID SMP UID WID Figure 42. Modelled irrigation district mean annual gross diversion demand for Scenario S1.

3. District Specific Variations Water demand for Scenario S1, representing current (1999) conditions for each district or for district groups, is presented in Figure 42. The mean gross diversion demand, in depth of water per irrigated unit area, varies widely among the districts. It ranges from a low of about 230 mm in the MVID to highs of about 570 mm and 550 mm in the EID and WID, respectively. There is also a wide range in the contribution of each water demand component to the gross diversion. For instance, return flow ranges from a low of about 12% of the gross diversion in the St. Mary Project (combined return flows from the St. Mary, Raymond and Taber Irrigation Districts), to a high of 53% in the AID and LID. Infrastructure losses range from a low of about 5% of the gross diversion for the AID and LID, to highs of about 18% for the MID, WID and EID. Table A-4 (Appendix) summarizes the gross diversion and component demands for each of the nine districts or district groups for Scenario S1. 4. Variation in Water Use Efficiencies Figure 43 shows mean annual irrigation demand as a percentage of the gross diversion demand for each scenario. The crop irrigation requirement for districts in the Oldman Basin ranges from 53% to 63% of the gross diversion demand. For districts in the Bow Basin, the crop irrigation requirement ranges from 41% to 52% of the gross diversion, reflecting higher losses and return flow.

Bow Basin Oldman Basin 100 100

80 80

60 60

(%) (%) 40 40

20 20

Water Demand Portions

Water Demand Portions 0 0 S1S2S3S4S5S6S7S8S9S10 S1 S2 S3 S4 S5 S6 S7 S8 S9 S10

Return Flow On-farm Losses Infrastructure Losses Crop Irrigation Requirement Figure 43. Modelled weighted-mean irrigation water demand as a percentage of gross diversion.

110 The crop irrigation requirement is generally a progressively increasing portion of the total diversion demand for Scenarios S1 to S10 for several reasons. ! Increases in on-farm and district efficiencies, and reduced return flow, primarily as a result of improved on-farm and district management, more efficient irrigation equipment and methods, and rehabilitation of district works, including more pipelines and automation of structures. ! Increases in water application rates from 80% of optimum crop requirements in Scenarios S1, S2, and S4 through S8, to 90% of optimum in Scenarios S3, S9 and S10. ! Irrigation expansion, primarily by in-fill within the existing serviced area and minimal new district infrastructure. This results in more compact districts and lower infrastructure losses and return flow when expressed in terms of depth of water per unit of irrigated area. ! Changes in crop mixes in Scenarios S5, S9 and S10 that increase the overall cropirrigation requirements. Most efficiency improvements reflected in the scenarios are extensions of current trends that are expected to continue. 5. Impacts of Water Management on Gross Diversion Demand Table 24 summarizes the effects on the total diversion demand of individual, one-at-a-time changes in irrigation management measures. Changes in irrigation areas and impacts of management measures are referenced to the Base Case (S1). An estimate of the gross diversion demand, generally within plus or minus 1.0%, can be made by adjusting the Scenario S1 gross diversion demand by the percent change impact of a single management measure or a combination of several management measures. For example, the expansion to 10% more than the 1991 Regulation limits (a 20.1% expansion beyond the 1999 irrigation area) would increase the gross diversion demand by 13.4% compared to 1999 conditions. If that expansion were accompanied by a continuing shift to more efficient on-farm systems, improved on-farm management, as well as reductions in district return flow, the gross diversion demand would be reduced to just 1.4% more than the 1999 requirements (13.4 - 5.7 - 3.0 - 3.3 = 1.4). Table 24. Impacts of management decisions on gross diversion demand. Irrigation Expansion from Gross Diversion Change in Management Area Base Case (S1) Demand Gross Diversion Variable (ha) (%) (dam3 ) (%) Base Case - 1999 conditions 490,385 2,187,018 Expansion to 1991Regulation limit 535,400 9.2 2,305,681 5.4 Expansion to 1991Regulation plus 10% 588,939 20.1 2,479,4831 13.41 Expansion to 1991Regulation plus 20 % 642,479 31.0 2,623,6661 20.01 Crop Mix Shift2 (increasing proportion of forage and specialty crops) 3.1 System Mix Shift2 (increasing proportion of higher efficiency sprinkler systems) -5.7 On-farm System Management Efficiency Improvements2 -3.0 Increase toward On-farm Crop Water Optimization2 9.5 Improvements in District Return Flow Management2 -3.3

1 Values represent changes resulting exclusively from the expansion variable. Actual expansion scenario modelling reflects minor on-farm system management improvements (Table 23). 2 Variables that can be applied in combination with any of the other management variables. The percentage change in gross diversion is referenced to the Base Case.

111 A crop mix shift and increasing on-farm water applications would, in turn, increase the gross diversion demand to 14.0% more than 1999 requirements (1.4 + 3.1 + 9.5 = 14.0). Table 24 can be used to indicate the projected impact of various management measures as a weighted average for all districts. For individual districts, the impact of such measures may be substantially different than shown in the table.

B. ANALYSIS OF WRMM WATER DEFICIT DATA The WRMM and IDM were used in tandem to determine the magnitude, frequency and duration of water supply deficits in the 10 scenarios. To compare the performance of the scenarios, a “deficit index" was computed for each scenario and for each basin (Appendix Tables A-5 and A-6). The deficit indices are expressions of the percentage of years that deficits within certain magnitudes would be experienced if all districts within each basin, and all irrigation blocks within each district, had an equal chance of experiencing those deficits. However, due to differences inwater licence priorities, and the location and size of headworks and district storage reservoirs, not all districts and all blocks within districts have the same deficit probability. Hence, the deficit indices should be used only to compare the relative performance of the scenarios, rather than as an absolute measure of the magnitude and frequency of deficits. The deficit indices within each magnitude class were ranked from lowest to highest. Generally, deficit rankings across all magnitude classes are consistent within a given scenario. Therefore, the deficit indices for any one magnitude class provide a quick overview comparison of scenario performance. Figure 44 summarizes scenario performance using the deficit indices for deficits greater than 100 millimetres. The figure shows: ! Deficits are substantially higher in the Oldman Basin than in the Bow Basin for most scenarios; and ! In both basins, deficits are the lowest in Scenario S1, representing 1999 conditions. In the Bow Basin, deficits are highest in Scenario S8, with 10% expansion from the 1991Regulation limits , using 1999 on-farm and district efficiencies, but irrigating to meet 90% of crop water requirements. Scenario S10, with 20% expansion, but with improved efficiencies, has slightly lower deficits than S8. In the Oldman Basin, deficits are highest in Scenario S10, with 20% expansion beyond the 1991Regulation limits.

10 Oldman 8 Bow

Deficit Index (%) 2

0 S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 Figure 44. Scenario performance for deficits greater than 100 mm.

112 The impact of water supply deficits is a function of the degree to which crop yields are affected, and is thus highly dependent on crop type. Figure 45 illustrates the diminishing yields for various crop types under a variety of deficit levels. For instance, a 125-mm deficit would have a relatively small effect on yields of alfalfa or canola, but a drastic impact on dry beans, tame hay or barley. Determining the impacts of deficits on farm enterprises would bring into play a number of other farm-specific factors. FFIRM runs are required to assess the impacts of deficits on farm enterprises under a variety of circumstances.

7 6

Type Soft Wheat 5 Barley 4 Tame Hay 3 Hard Wheat 2 (thousands) Canola 1 Dry Beans 0

Yields (kg/ha) by Crop 0 25 75 125 175 225 Deficit Level (mm)

Type Silage Corn 60 Sugar Beets Potatoes 40 Silage Barley

(thousands) 20 Alfalfa

Yields (kg/ha) by Crop 0 25 75 125 175 225 Deficit Level (mm)

Figure 45. Yield response to irrigation deficits for various crop types.

113 C. ANALYSIS OF FFIRM OUTPUT ON IMPACTS OF IRRIGATION DEFICITS FFIRM runs were conducted for six climate and crop regions, two to four typical types of farm enterprises within each region (as determined by crop mix), and three different starting debt levels. In total, 57 different farm enterprises were assessed for seven scenarios – S1, S3, S4, S7, S8, S9 and S10. FFIRM tracks the farm financial characteristics during the entire 68-year period, 1928 to 1995. Key performance indicators are net farm income, debt and equity levels, and the likelihood of financial insolvency of the farm enterprise. Analyses of the output from the FFIRM runs led to the following key findings. Crop Mix – Farms that rely only on cereals and oilseeds were significantly less profitable than farms that also produced specialty crops or forages (Figures 38 and 39). Including a higher value crop provided the opportunity to optimize returns in deficit years by shifting water applications from low value crops to higher value crops. Farm Debt Level – Farms with high starting debt levels had considerably reduced net farm incomes over time. These farm types, particularly cereals and oilseed farms, generally had low net farm income (NFI). High starting debt levels considerably increased their risk of financial insolvency. High starting debt levels also reduced NFI of farms that included a specialty crop in their mix, but these farms were better able to deal with higher interest costs due to higher crop revenues. Irrigation Water Application Levels – For scenarios that maintained the current level of crop water application (80%), such as S4 and S7, most farm enterprises experienced a significant decrease in average NFI from 1999 (S1) conditions (Figure 46). This is due to more frequent water deficit years as a result of irrigation expansion, and lower incomes in those years. The risk of insolvency either remained the same or increased slightly (Figure 47). Most farm types would experience a higher average NFI with time under water management Scenarios S3, S9 and S10. Higher average incomes are due to the higher on-farm water application level (90%), in combination with improved on-farm and districtwater management efficiencies (Figure 48). Because of higher revenues in the non-deficit years, producers would be in a better position to withstand lower revenues in the deficit years. The risk of insolvency remained the same or decreased marginally (Figure 49). For scenarios S9 and S10 to be favourable from a farm financial perspective, all water management related improvements would have to be fulfilled, particularly the increased water applications.

114 160 120 S1 S7 80 40 0

Average NFI

(in thousands $) -40 -80 13579111315171921232527 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 Simulated Representative Farms (1-57)

Figure 46. Average net farm incomes for Scenarios S1 and S7.

100 88% 75

(%) 5 9% 0% 0% 4% 0 Representative Farms Much Lower No Higher Much Lower Change Higher

Figure 47. Risk of insolvency for Scenario S7 compared to S1.

160 120 S1 S9 80 40 0

Average NFI

(in thousands $) -40 -80 13579111315171921232527 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 Simulated Representative Farms (1-57)

Figure 48. Average net farm incomes for Scenarios S1 and S9.

100 89% 75

(%) 5 5% 5% 0% 0% 0 Representative Farms Much Lower No Higher Much Lower Change Higher Figure 49. Risk of insolvency for Scenario S9 compared to S1.

115 D. DETAILED ASSESSMENT OF SELECTED EXPANSION SCENARIOS Scenarios S1, S3, S9 and S10 were examined in detail with respect to water demand and supply, and the impact of water deficits on farm financial sustainability. Scenarios S3, S9 and S10 represent future conditions, with: ! increasing levels of irrigation expansion; ! improved on-farm and district efficiencies; ! changing crop mixes; and ! increased levels of crop water application. Scenario S1 represents 1999 conditions and is presented as a basis for comparison. Profiles of modelling output for irrigation districts in the Bow and Oldman basins are provided for each scenario in Figures 50 to 54. Each figure has four parts. Parts a) and c) deal with the Bow Basin districts; parts b) and d) with the Oldman Basin districts. The profiles include 68-year histograms showing the irrigation water demands and deficits in the river basins (parts a and b); and a bar graph showing the probability of deficits of various magnitudes, a line graph showing the areal extent of the deficits, a line graph showing the average net farm incomes for each representative farm modelled in the Bow and Oldman basins, and a line graph showing the probability of negative net farm incomes in any one year (parts c and d). The teal-colored bars in each histogram show the variation in the annual weighted-average irrigation demand, as determined using the IDM. The weighted-average demand for the entire 68-year period is shown as black horizontal dashed lines. There is considerable variation in total demand from one year to another, due in large part to the annual variation in weather conditions. Growing season precipitation on the irrigated lands has the greatest influence on irrigation demand. Evapotranspiration is also a factor, but usually of lesser significance. Deficits usually correspond to low runoff years caused by below average mountain snow pack and rainfall. Depleted soil moisture and reservoir storage from previous years can also have a significant effect on deficits. The extent of any shortfall in water supply, as determined by the WRMM, is shown as red bars, superimposed over the teal demand bars. The red horizontal dashed lines show the weighted-averageRegulation licence water allocation for all the irrigation districts supported by the basin. The licence volumes were determined in 1991 when the irrigation expansion guidelines were established. It provides a reference to indicate the extent to which the annual demand for each scenario approaches or exceeds the proposed allocations. All districts in the Oldman Basin are licensed up to the 1991 licence allocations. Not all districts in the Bow Basin are licensed to that extent, although applications have been made and are under review.

116 The deficit frequency graphs show the probability of one or more irrigation blocks in the basin experiencing deficits of various magnitudes. For instance, there would be a 6.5% probability that irrigation blocks in the Bow Basin would experience a deficit between 1 mm and 50 mm (Figure 50c). There would be an 8.5% probability that a similar deficit would occur in the Oldman Basin (Figure 50d). The deficit frequency graphs provide a little more insight into the frequency and magnitude of deficits that do not show up in the histograms. The bar graphs are based on the same deficit data as the histograms, without the diminishing effect of averaged deficits for all blocks in the basin. The areal extent of deficits graphs show how wide spread deficits of various frequencies and magnitudes would be within a basin. For instance, Figure 50c shows that in 30 years out of 68, a deficit of between 1 millimetre and 50 millimetres would occur on less than 20% of the irrigated land in the Bow Basin. A deficit of between 51 and 100 millimetres would occur in three out of 68 years on less than 20% of the irrigated land. Graphs also show the average NFI during the 68-year period for each of the representative farms that were simulated using the FFIRM. In the Bow Basin, a total of 27 farms were simulated; in the Oldman Basin, 30 farms were simulated. Each farm differed on the basis of agro-climatic region, crop mix and/or the starting farm debt and asset level. Average NFI for all the representative farms has been sorted from lowest to highest. This permits an easy assessment of the overall financial outcome for each basin and scenario. The figures also show the results for Scenario S1 to provide a direct comparison with Scenarios S3, S9 and S10. Because of the sorting, the results for specific farms are not necessarily plotted in the same order for each scenario. Graphs also show the probability of negative NFI in any one year for the representative farms. A probability of 100% indicates that the representative farm could expect a negative NFI every year. A probability of 20% indicates the farm could expect a negative NFI in one year out of five, on average. The graphs for Scenarios S3, S9 and S10 show the results for Scenario S1 for comparison purposes. A scenario line lower than the S1 line indicates the scenario would have less risk of negative NFI than currently experienced. Each set of graphs includes a discussion of the significant findings and comparisons for each scenario and basin. The discussion is continuous throughout the four pages for each scenario. The detailed discussion of the four scenarios in this chapter capture the full range of option combinations related to irrigation expansion and water management. Six additional scenarios were simulated to provide a more complete understanding of the impacts of individual management measures. Histograms showing annual demands and deficits, and graphs showing the deficit frequencies and areal extent for the six additional scenarios modelled (S2, S4, S5, S6, S7, and S8) are included in the Appendix as figures A-1 through A-12.

117 900

800 Deficit Demand Regulation licence depth per unit area 700 Weighted-average demand for all years

600

verage 500

400

Weighted-A 300

Irrigation Demand and Deficit (mm) 200

100

1928

1933

1938

1943

1948

1953

1958

1963

1968

1973

1978

1983

1988

1993

Figure 50a. Scenario S1 total demands and deficits - Bow Basin districts.

Scenario S1 - Base Case (1999) Conditions Irrigation area: Bow Basin 221,526 hectares Strathmore Oldman Basin 268,859 hectares Crop mix 1999 On-farm system mix 1999 On-farm management 1999 Brooks Crop water management 1999 Return flow management 1999

1991Regulation licence volume: Bow Basin 1,881,088 cubic decametres Oldman Basin 1,738,003 cubic decametres Scenario weighted-average demand: Bow Basin 1,165,466 cubic decametres Oldman Basin 1,021,552 cubic decametres

118 900

800 Deficit Demand Regulation licence depth per unit area 700 Weighted-average demand for all years

600

verage 500

400

Weighted-A 300

Irrigation Demand and Deficit (mm) 200

100

1928

1933

1938

1943

1948

1953

1958

1963

1968

1973

1978

1983

1988

1993

Figure 50b. Scenario S1 total demands and deficits - Oldman Basin districts.

Discussion of Results The weighted-average unit demand for the 68-year period is 526 mm in the Bow Basin and 380 mm in the Oldman Basin. The higher total unit demands in the Bow Basin are primarily due to higher Medicine Hat evaporation losses from reservoirs and much higher return flows than for the Oldman Basin districts. The variability in demand in the two basins is about the same. The 1991 licence allocation is well above the demands in all years, in both basins. Lethbridge The modelling shows occasional deficits would be experienced in the Bow Basin, but their frequency and magnitudes would be low and their impacts insignificant. Deficits would be slightly higher in both magnitude and frequency in the Oldman Basin, but still insignificant. It is generally considered that deficits up to 50 mm are of little consequence in terms of overall irrigation production. Deficits greater than 100 mm are significant. In this and other scenarios, deficits within some districts and some irrigation blocks would be higher than the weighted averages. The deficit-frequency graphs show deficits would be small and infrequent in both basins. Deficits greater than 100 mm would be rare.

119 30 70 Deficit Frequency Areal Extent of Deficits 25 60 1-50 mm 50 51-100 mm 20 101-150 mm 40 151-200 mm 15 201-250 mm 30 251+ mm 10 20

5 No. of Years10 Out of 68

Frequency of Occurrence (%) 0 0 1-50 51 - 100 101 - 150 151 - 200 201 - 250 > 250 1-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 > 80 Deficit Range (mm) Portion of Basin Affected (%)

160 100 Average NFI Probability of Negative NFI 120 S1 80 S1 80 60 40 40 $1000 0 -40 20 -80 0 1 3 5 7 9 11 13 15 17 19 21 23 25 27 1 357911 13 15 17 19 21 23 25 27

Probability of Neg. NFI (%) Simulated Representative Farms (1-27) Simulated Representative Farms (1-27)

Figure 50c. Scenario S1 irrigation deficits and farm incomes - Bow Basin districts.

Discussion cont’d... The deficit-areal extent graphs indicate that in the Bow Basin, deficits between 100 and 200 mm may affect between 11 and 20% of the irrigated land in one year out of 68. In the Oldman Basin, minor Strathmore deficits (less than 50 mm) affecting up to 10% of the irrigated area would be common. Occasionally these deficits could affect up to 70% of the irrigated area. Significant deficits (more than 100 mm) are rare.

Brooks The average NFI for the simulated representative farms in the Bow Basin ranged between –$29,000 and +$71,000. Six of the 27 representative farms in the basin had a negative average NFI. In general, the lower NFI was associated with farm types that emphasize grains and oilseeds. The highest NFI was associated with farm types that include specialty crops within the mix. In the Oldman Basin, NFI ranged from –$54,000 to +$68,000. Five of the 30 farms had a negative average NFI. In general, NFI for the simulated farms in the Oldman Basin was a little higher than that of the Bow Basin, due to the higher number of specialty crops included in the crop mixes of Oldman Basin farms.

120 30 70 Deficit Frequency Areal Extent of Deficits 25 60 1-50 mm 50 51-100 mm 20 101-150 mm 40 151-200 mm 15 201-250 mm 30 251+ mm 10 20

5 No. of Years10 Out of 68

Frequency of Occurrence (%) 0 0 1 - 50 51 - 100 101 - 150 151 - 200 201 - 250 > 250 1-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 > 80 Deficit Range (mm) Portion of Basin Affected (%)

160 100 Average NFI Probability of Negative NFI 120 80 S1 S1 80 60 40 40 $1000 0 -40 20 -80 0 1 357911 13 15 17 19 21 23 25 27 29

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 Probability of Neg. NFI (%) Simulated Representative Farms (1-30) Simulated Representative Farms (1-30)

Figure 50d. Scenario S1 irrigation deficits and farm incomes - Oldman Basin districts.

Ten of the representative farms (37%) in the Bow Basin and eight (27%) in the Oldman Basin have a probability of a negative NFI in greater than 20% of the years (one year in five, on average). About 30% of the representative farms in each basin have little or no risk of a Medicine negative NFI. Hat

KEY FINDINGS Lethbridge ! At the current level of irrigation development, and with current on-farm and district management practices, the potential for significant irrigation deficits is low. ! Even with the low frequency and magnitude of deficits, farm enterprises based on lower value crops, such as grains and oilseeds, may be at financial risk in both basins. This likely reflects the reality that irrigation in much of southern Alberta cannot be sustained with conventional crop production, due to the high input costs and low crop prices.

121 900

800 Deficit Demand 700 Regulation licence depth per unit area Weighted-average demand for all years 600

verage 500

400

Weighted-A 300

Irrigation Demand and Deficit (mm) 200

100

1928

1933

1938

1943

1948

1953

1958

1963

1968

1973

1978

1983

1988

1993

Figure 51a. Scenario S3 total demands and deficits - Bow Basin districts.

Scenario S3 - Expansion to 1991Regulation Limits Irrigation area: Bow Basin 239,170 hectares Strathmore Oldman Basin 296,230 hectares Crop mix 1999 On-farm system mix 1999 On-farm management Improved Brooks Crop water management Near optimum (90%) Return flow management Improved

1991Regulation licence volume: Bow Basin 1,881,088 cubic decametres Oldman Basin 1,738,003 cubic decametres Scenario weighted-average demand: Bow Basin 1,267,601 cubic decametres Oldman Basin 1,107,900 cubic decametres

122 900

800 Deficit Demand Regulation licence depth per unit area 700 Weighted-average demand for all years

600

verage 500

400

Weighted-A 300

Irrigation Demand and Deficit (mm) 200

100

1928

1933

1938

1943

1948

1953

1958

1963

1968

1973

1978

1983

1988

1993

Figure 51b. Scenario S3 total demands and deficits - Oldman Basin districts.

Discussion of Results In the Bow River Basin, the weighted-average unit demand for the 68-year period increased only slightly from 526 mm in Scenario S1 to 530 mm in S3, in spite of a 24% increase in crop irrigation requirement. Medicine Hat The crop irrigation requirement was almost entirely offset by efficiency improvements and reduced return flow. In the Oldman Basin, the crop irrigation requirement increased by 8%, and the unit demand decreased by about 2%, again reflecting the increase in efficiencies. For all Lethbridge districts, the average annual volume of water required to support the 9.2% expansion and increased irrigation applications was about 8.6% higher than in Scenario S1. The 1991Regulation licence allocation remains well above the highest demand years in both basins. The frequency of water supply deficits in the Bow Basin is much more noticeable for Scenario S3 than for Scenario S1, although the magnitudes remain low. Deficits would be higher in the Oldman Basin. Should back-to-back deficits occur in the Oldman Basin, similar to those of the 1930s and early 1940s, they would be cause for concern.

123 30 70 Deficit Frequency Areal Extent of Deficits 25 60 1-50 mm 50 51-100 mm 20 101-150 mm 40 151-200 mm 15 201-250 mm 30 251+ mm 10 20 5 No. of Years10 Out of 68

Frequency of Occurrence (%) 0 0 1-50 51 - 100 101 - 150 151 - 200 201 - 250 > 250 1-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 > 80 Deficit Range Portion of Basin Affected (%)

160 100 Average NFI Probability of Negative NFI 120 80 S1 S1 80 S3 60 S3 40 40 $1000 0 -40 20 -80 0 1 357911 13 15 17 19 21 23 25 27 1 3 5 7 9 11 13 15 17 19 21 23 25 27 Probability of Neg. NFI (%) Simulated Representative Farms (1-27) Simulated Representative Farms (1-27)

Figure 51c. Scenario S3 irrigation deficits and farm incomes - Bow Basin districts.

Discussion cont’d... A deficit greater than 100 mm would be experienced in about 2% of years in the Bow Basin. Deficits of that magnitude would not affect more than 20% of the irrigated land in the basin. A deficit greater than 100 mm Strathmore would be experienced in about 2.5% of years in the Oldman Basin. Deficits of that magnitude could affect up to 50% of the irrigated area in a small percentage of years.

Brooks In Scenario S3, the average NFI for the 68-year period would increase from that of S1 for all representative farms in the Bow Basin, despite a somewhat greater frequency of water deficits. The higher on-farm water application rates for Scenario S3 result in higher yields in non-deficit years, and therefore higher NFI. The improved financial outlook in the non-deficit years more than offsets the increased frequency of water deficits, and associated decline in NFI. Only one of the 27 farms in the Bow Basin had a negative average NFI, compared with six in Scenario S1. All of the farms in the Oldman Basin show an increase in NFI compared to Scenario S1. The farms growing higher value crops showed a significant increase. Two of the 30 representative farms in the Oldman Basin had a negative average NFI, compared with five in Scenario S1.

124 30 70 Deficit Frequency Areal Extent of Deficits 25 60 1-50 mm 50 51-100 mm 20 101-150 mm 40 151-200 mm 15 201-250 mm 30 251+ mm 10 20

5 No. of Years10 Out of 68

Frequency of Occurrence (%) 0 0 1 - 50 51 - 100 101 - 150 151 - 200 201 - 250 > 250 1-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 > 80 Deficit Range (mm) Portion of Basin Affected (%)

160 100 Average NFI Probability of Negative NFI 120 80 S1 S1 80 S3 60 S3 40 40 $1000 0 -40 20 -80 0 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 1 357911 13 15 17 19 21 23 25 27 29

Probability of Neg. NFI (%) Simulated Representative Farms (1-30) Simulated Representative Farms (1-30)

Figure 51d. Scenario S3 irrigation deficits and farm incomes - Oldman Basin districts.

In the Bow Basin, the probability of negative NFI declined for most farms, despite the increase in water deficits. Deficits would be small, and water applications in most deficit years would be greater than under

Scenario S1, with crop water application at 80% of optimum. In the Medicine Oldman Basin, the probability of negative NFI declined for 9 of the 30 Hat farms, but slightly increased for some. In the Oldman Basin the magnitude of the deficits was larger, resulting in lower crop water applications than in Scenario S1 for some farms. Lethbridge

KEY FINDINGS ! Improvements in irrigation efficiencies and reduced return flow are essential to minimize water supply deficits caused by increased crop irrigation applications and expansion of the irrigated areas. ! Despite more frequent and higher deficits in Scenario S3, all farms experienced higher average NFI because of increased on-farm water application levels (90%) and higher yields during non-deficit years. ! Producers would be in a better position to withstand lower revenues in deficit years because of higher revenues in non-deficit years.

125 900

Deficit Demand 800 Regulation licence depth per unit area Weighted-average demand for all years 700

600

verage 500

400

Weighted-A 300

Irrigation Demand and Deficit (mm) 200

100

1928

1933

1938

1943

1948

1953

1958

1963

1968

1973

1978

1983

1988

1993

Figure 52a. Scenario S9 total demands and deficits - Bow Basin districts.

Scenario S9 - Expansion to 10% Beyond 1991Regulation Limits Irrigation area: Bow Basin 263,086 hectares Strathmore Oldman Basin 325,853 hectares Crop mix Future On-farm system mix Future On-farm management Improved Brooks Crop water management Near optimum (90%) Return flow management Improved

1991Regulation licence volume: Bow Basin 1,881,088 cubic decametres Oldman Basin 1,738,003 cubic decametres Scenario weighted-average demand: Bow Basin 1,304,907 cubic decametres Oldman Basin 1,173,071 cubic decametres

126 900

800 Deficit Demand Regulation licence depth per unit area 700 Weighted-average demand for all years

600

verage 500

400

Weighted-A 300

Irrigation Demand and Deficit (mm) 200

100

1928

1933

1938

1943

1948

1953

1958

1963

1968

1973

1978

1983

1988

1993

Figure 52b. Scenario S9 total demands and deficits - Oldman Basin districts.

Discussion of Results In the Bow River Basin, the weighted-average unit demand decreased from 526 mm in Scenario S1 to 496 mm in Scenario S9, in spite of a 26% increase in crop irrigation requirement. In the Oldman Basin, the unit crop Medicine irrigation requirement increased by 11%, and the unit demand decreased Hat from 380 mm in Scenario S1 to 360 mm in S9, reflecting the increase in efficiencies. The highest demand years for the Bow Basin districts were still well below the 1991Regulation licence allocation for that basin. In Lethbridge the Oldman Basin, the highest demand years remained somewhat below the 1991 Regulation. The frequency and magnitude of water supply deficits in the Bow Basin were greater than S1 deficits, but not much different than S3. Deficits in the Oldman Basin would be significantly higher than in S3. Should a clustering of deficits similar to those of the 1930s and 1980s reoccur, it would be a concern to producers. On the positive side, there was a period of about 40 consecutive years with no significant deficits. In the Bow Basin, deficits greater than 100 mm would still be experienced in only about 2% of years, and would impact up to 20% of the irrigated area in the basin. In the Oldman Basin, deficits greater than

127 30 70 Deficit Frequency Areal Extent of Deficits 25 60 1-50 mm 50 51-100 mm 20 101-150 mm 40 151-200 mm 15 201-250 mm 30 251+ mm 10 20 5 No. of Years10 Out of 68

Frequency of Occurrence (%) 0 0 1 - 50 51 - 100 101 - 150 151 - 200 201 - 250 > 250 1-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 > 80 Deficit Range (mm) Portion of Basin Affected (%)

160 100 Average NFI Probability of Negative NFI 120 80 S1 S1 80 S9 60 S9 40 40 $1000 0 -40 20 -80 0 1 357911 13 15 17 19 21 23 25 27

1 3 5 7 9 11 13 15 17 19 21 23 25 27 Probability of Neg. NFI (%) Simulated Representative Farms (1-27) Simulated Representative Farms (1-27)

Figure 52c. Scenario S9 irrigation deficits and farm incomes - Bow Basin districts.

Discussion cont’d... 100 mm would be experienced in about 4.5% of the years. Deficits of this magnitude could impact up to 60% of the irrigated area in the basin.

Strathmore The financial impact on Bow Basin district farms would be improved compared to the Base Case Scenario, and would be similar to Scenario S3. Two of the 27 representative farms showed a negative average NFI. The financial gains in the Oldman Basin districts would be less than

Brooks those for the Bow districts. Gains in NFI from the current situation would be minor for most of the 30 farms, but more significant for farms with an emphasis on specialty crops. Financial performance of farms in the Oldman Basin declined from Scenario S3. In the Bow Basin, the risk of negative NFI was lower than Scenario S1, but marginally higher than S3. In the Oldman Basin, most of the representative farms had an increase in the risk of negative NFI compared to Scenario S1. However, the risk was still less than 20% (one year in five). The increase in the probability of negative NFI in the Oldman Basin indicated an increase in the annual income variability from current conditions. However, the long-term average NFI would be the same or higher than for Scenario S1.

128 30 70 Deficit Frequency Areal Extent of Deficits 25 60 1-50 mm 50 51-100 mm 20 101-150 mm 40 151-200 mm 15 201-250 mm 30 251+ mm 10 20 5 No. of Years10 Out of 68

Frequency of Occurrence (%) 0 0 1 - 50 51 - 100 101 - 150 151 - 200 201 - 250 > 250 1-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 > 80 Deficit Range (mm) Portion of Basin Affected (%)

160 100 Average NFI Probability of Negative NFI 120 80 S1 S1 80 S9 60 S9 40 40 $1000 0 -40 20 -80 0 1 357911 13 15 17 19 21 23 25 27 29

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 Probability of Neg. NFI (%) Simulated Representative Farms (1-30) Simulated Representative Farms (1-30)

Figure 52d. Scenario S9 irrigation deficits and farm incomes - Oldman Basin districts.

KEY FINDINGS ! With 10% expansion beyond theRegulation limit (20% expansion beyond the 1999 irrigation area) in the Bow Basin, the probability of Medicine deficits greater than 100 mm remained low. Hat ! All farms in the Bow Basin would experience higher average NFI and lower risks of negative NFI than in Scenario S1. ! With 10% expansion beyond theRegulation limit (20% expansion Lethbridge beyond the 1999 irrigation area) in the Oldman Basin, the probability of deficits greater than 100 mm almost doubled compared to Scenario S3. ! NFI in the Oldman Basin decreased from Scenario S3. NFI increased marginally from the Base Case on 80% of farms, but more significantly on the other 20%. However, the risk of negative NFI increased on 60% of the farms, indicating higher variability in NFI. ! The farms with increased risk of negative NFI are still at a relatively low risk, with probabilities of negative NFI at less than 20% (one year in five).

129 900

800 Deficit Demand Regulation licence depth per unit area 700 Weighted-average demand for all years

600

verage 500

400

Weighted-A 300

Irrigation Demand and Deficit (mm) 200

100

1928

1933

1938

1943

1948

1953

1958

1963

1968

1973

1978

1983

1988

1993

Figure 53a. Scenario S10 total demands and deficits - Bow Basin districts.

Scenario S10 - Expansion to 20% Beyond 1991Regulation Limits Irrigation area: Bow Basin 287,003 hectares Strathmore Oldman Basin 355,476 hectares Crop mix Future On-farm system mix Future On-farm management Improved Brooks Crop water management Near optimum (90%) Return flow management Improved

1991Regulation licence volume: Bow Basin 1,881,088 cubic decametres Oldman Basin 1,738,003 cubic decametres Scenario weighted-average demand: Bow Basin 1,386,224 cubic decametres Oldman Basin 1,258,385 cubic decametres

130 900

800 Deficit Demand Regulation licence depth per unit area 700 Weighted-average demand for all years

600

verage 500

400

Weighted-A 300

Irrigation Demand and Deficit (mm) 200

100

1928

1933

1938

1943

1948

1953

1958

1963

1968

1973

1978

1983

1988

1993

Figure 53b. Scenario S10 total demands and deficits - Oldman Basin districts.

Discussion of Results In the Bow Basin, the weighted-average unit demand for Scenario S10 decreased to 483 mm from 496 mm in Scenario S9. The decrease was a result of further expansion by in-fill using existing infrastructure, making Medicine Hat the districts more compact and therefore more efficient. In the Oldman Basin, the unit demand decreased to 354 mm from 360 mm in Scenario S9. These unit demands were about 8% lower than current (S1) demand, in spite of increased irrigation applications and crops that use more water. For Lethbridge all districts, the average annual volume of water required to support the 31% expansion (from S1), change in crop types, and increased irrigation applications in the two basins would be 21% higher than in Scenario S1. The irrigation demands for the Bow Basin districts in 1929 and 1961 would be close to the 1991 licence allocation for that basin. In the Oldman Basin, the demands for 1936 and 1988 would be up to the 1991 licence allocation. These were both deficit years, so actual diversions would be well below the licence allocation. Deficits in the Bow Basin would be frequent but relatively low in magnitude. In the Oldman Basin, there would be a marked increase in the

131 30 70 Deficit Frequency Areal Extent of Deficits 25 60 1-50 mm 50 51-100 mm 20 101-150 mm 40 151-200 mm 15 201-250 mm 30 251+ mm 10 20

5 No. of Years10 Out of 68

Frequency of Occurrence (%) 0 0 1-50 51 - 100 101 - 150 151 - 200 201 - 250 > 250 1-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 > 80 Deficit Range (mm) Portion of Basin Affected (%)

160 100 Average NFI Probability of Negative NFI 120 80 S1 S1 80 S10 60 S10 40 40 $1000 0 -40 20 -80 0 1 357911 13 15 17 19 21 23 25 27

1 3 5 7 9 11 13 15 17 19 21 23 25 27 Probability of Neg. NFI (%) Simulated Representative Farms (1-27) Simulated Representative Farms (1-27)

Figure 53c. Scenario S10 irrigation deficits and farm incomes - Bow Basin districts.

Discussion cont’d... magnitude of deficits from Scenario S9. Deficits similar to those prevalent in the 1930s and 1980s, with several periods of consecutive deficit years, would be of concern. Strathmore In the Bow Basin, deficits greater than 100 mm would be experienced in about 2.5% of years, about the same as deficits in the Oldman Basin for S3. Deficits of this magnitude could affect up to 20% of the irrigated Brooks area in the Bow Basin. For Scenario S10, deficits greater than 100 mm would be expected in the Oldman Basin about 8.7% of years, and could affect up to 60% of the irrigated area. The current (S1) probability of deficits greater than 100 mm in the Oldman Basin was less than 1%. Average NFI for Bow Basin farms would be similar to Scenario S9, continuing to show improvements from Scenario S1. In the Oldman Basin, average NFI would decline slightly from Scenario S9. No farms would experience any appreciable decline in average NFI from Scenario S1, but a few would experience an appreciable gain. The risk of negative NFI would be significantly lower than Base Case for about 35% of the farms in the Bow Basin, and about the same for the remaining 65%.

132 30 70 Deficit Frequency Areal Extent of Deficits 25 60 1-50 mm 50 51-100 mm 20 101-150 mm 40 151-200 mm 15 201-250 mm 30 251+ mm 10 20 5 No. of Years10 Out of 68

Frequency of Occurrence (%) 0 0 1 - 50 51 - 100 101 - 150 151 - 200 201 - 250 > 250 1-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 > 80 Deficit Range (mm) Portion of Basin Affected (%)

160 100 Average NFI Probability of Negative NFI 120 80 S1 S1 80 S10 60 S10 40 40 $1000 0 -40 20 -80 0 1 357911 13 15 17 19 21 23 25 27 29

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 Probability of Neg. NFI (%) Simulated Representative Farms (1-30) Simulated Representative Farms (1-30)

Figure 53d. Scenario S10 irrigation deficits and farm incomes - Oldman Basin districts.

In the Oldman Basin, about 25% of the farms would have a decreased probability of negative NFI, but most others would have an increased risk, albeit still not greater than 20%.

Medicine Hat KEY FINDINGS ! With increased on-farm and district efficiencies, and increased irrigation water applications to 90% of crop water requirements, an Lethbridge expansion of 20% beyond theRegulation limit (30% beyond the 1999 irrigation area) in the Bow Basin could be sustained without serious water supply risks or negative farm financial risks. ! Expansion by 20% beyond theRegulation limit (30% beyond the 1999 irrigation area) in the Oldman Basin could result in significant deficits in a sizable portion of the irrigated area in the basin, even with efficiency improvements. Only a few farm types would experience higher average NFI compared to current income.

133 E. CONCLUSIONS

Based on simulation modelling conducted for the Irrigation Water Management Study, the following key conclusions on potential irrigation expansion have been drawn.

Assuming continued improvements in on-farm and district infrastructure and water management, overall irrigation water management efficiencies could improve in the Oldman Basin districts from the 1999 level of 53% to 64% in the future. Similarly, efficiencies are projected to increase from 40% to 55% for the Bow Basin districts.

The potential for efficiency gains is greater for Bow Basin districts than for Oldman Basin districts, primarily because of infrastructure configuration and the density of irrigation parcels relative to length of conveyance works. Also, a lower percentage of district infrastructure has been rehabilitated and a higher percentage of surface irrigation is still practiced in the Bow Basin.

Based on modelling conducted in this study, a 10% to 20% expansion in the irrigated area beyond the 1991Regulation limits is sustainable in districts supported by the Bow Basin, with improvements in water use efficiency, reduced return flows, and higher crop water applications.

Financial performance indicators for Scenarios S9 and S10 showed improvements compared to Base Case conditions in the Bow Basin, in spite of higher irrigation deficits. This conclusion does not apply equally to all districts nor to all irrigation blocks within the districts. More detailed analyses are required to determine the impacts of expansion on individual districts and blocks.

Modeling output suggests an expansion in the irrigated area of the Oldman Basin of up to 10% beyond the 1991Regulation limits could be considered, with efficiency improvements, reduced return flows, and higher crop water applications.

A cautious approach to irrigation expansion in the Oldman Basin is recommended. Most financial performance indicators show improvements compared to the 1999 situation. However, some irrigation blocks and some districts should probably not expand beyond the 1991Regulation limits. More detailed analyses of individual district modelling output are required for decision making.

Financial modelling indicates irrigation farm financial performance can be improved compared to Base Case conditions, even with irrigation expansion and more frequent and higher water supply deficits.

Comparison of model output for expansion scenarios to current conditions indicated that average net farm incomes increased, and the risk of insolvency decreased from current conditions, for most representative farms. The probability of negative net farm income in any one year decreased for all farms in the Bow Basin districts, but increased for some farms in the Oldman Basin, indicating higher variability in annual income in the Oldman Basin.

134 Prerequisites to improved farm financial performance are on-farm and district water use efficiency improvements, reduced return flows, higher crop water applications, and crop mixes that include at least one high value crop. Improved efficiencies and reduced return flows will minimize the magnitude and frequency of water supply deficits. Higher crop water applications will increase yields and revenues in non-deficit years, so producers are in a better position to withstand lower revenues in deficit years. Farms that irrigate only cereals and oilseeds are considerably less profitable than farms that include higher value specialty crops or forages. Including a higher value crop in the mix provides an opportunity to maximize revenues by shifting water applications from low to high value crops.

Irrigation water supply deficits less than 100 mm per year are not considered to have serious financial consequences for most producers.

At the crop level, the net effect of a specified water supply deficit is only a portion of that deficit. The actual net effect at the crop level is somewhat reduced because a portion of the projected deficit consists of losses incurred through water application inefficiencies that were already accounted for in the irrigation demand. These on-farm losses do not occur if water is not available for diversion to meet the projected irrigation demand. For example, a projected 100 mm deficit in the gross diversion supply may only translate into a 70 mm to 75 mm deficit at the crop level. Irrigators can also redistribute available water to those crops generating higher net revenues. As a result, the impact of smaller projected gross diversion deficits (less than 100 mm) is unlikely to have much financial significance.

135 VII.

Chapter Benefits of Irrigation Development Chapter VII. Benefits of Irrigation Development

A. INTRODUCTION The overall objective of the Irrigation Water Management Study was to provide reliable information on current and future water requirements and on the water management practices necessary for a sustainable agricultural industry in Alberta. A sustainable industry is one that is economically viable and socially acceptable. It preserves natural resources and the environment for the use and enjoyment of future generations. This chapter discusses the current contributions of irrigation to the economic, social and environmental well-being of Albertans, and the potential economic impacts of an expanded, sustainable irrigation industry. Irrigation expansion is important to the health of the agricultural industry. Improving the viability of individual farming enterprises, increasing the efficiency and economic viability of irrigation districts, and contributing to the economic and social objectives of the province are the expected outcomes of irrigation expansion in southern Alberta. Intensification of irrigation, and the concomitant expansion of the irrigated area and increases in agri-food processing, will bring numerous direct and indirect benefits in the future. The irrigation districts in southern Alberta, with their extensive networks of canals, pipelines, drains and reservoirs, have had a profound impact on the entire region – an impact that extends well beyond the farm gate. Secure supplies of good quality water have always been a concern to farmers and ranchers in southern Alberta. Urban communities face similar water concerns. Local surface water supplies are often unreliable; groundwater supplies, where adequate quantity can be found, are often of poor quality. Although the initial development of water diversions and irrigation infrastructurein southern Alberta was predicated on increasing and stabilizing crop production, the irrigation distribution works soon became a supplemental source, and often the sole source, of good quality water for domestic, stock watering, municipal and industrial uses. Dependence on the irrigation infrastructure for non-irrigation uses of water became entrenched in the region’s social fabric and has remained so. There would be very few permanent standing water bodies in southern Alberta without irrigation reservoirs or natural water bodies supplemented by irrigation diversions. Individual municipalities and the provincial government have developed parks and recreation areas on these water bodies to provide highly popular, water-based recreational opportunities that would otherwise not be possible. Irrigation diversions have also been used to develop habitat for wildlife. Prior to the 1970s, these projects were often operated in association with uncontrolled seepage from irrigation canals. However, as irrigation districts strive to improve irrigation efficiencies, rehabilitation of canals and replacement of canals with pipelines has essentially eliminated seepage. Most of the wildlife projects are now supported by controlled releases from the distribution system. New wildlife projects have been developed as districts make conscious efforts to address quality of life and environmental sustainability issues.

139 B. 1999 BENEFITS OF IRRIGATION DEVELOPMENT

1. Primary Agricultural Production The approximately 525,000 hectares of land now under irrigation in the 13 irrigation districts comprise about 4% of the cultivated land in Alberta and is farmed by about 8.3% of Alberta's producers. Irrigation impacts farm production in four important ways. ! Increased yields – When irrigated, yields of conventional crops, (crops grown on both dryland and irrigated land,) are commonly increased two to three-fold or more in the drier regions of southeastern Alberta. ! Crop diversification – Irrigation makes possible the production of a broader range of crops, many of which are considered specialty crops, (crops that are generally not viable under dryland agriculture). These are typically higher value crops, such ascorn, beans, peas, sugar beets and potatoes, t hat can also be processed in Alberta. ! Stability – Irrigated crop yields are more stable and reliable, resulting in greater income stability, reduced crop insurance costs, and greater assurance in meeting production targets and marketing contracts. ! Diversity – Irrigation fosters diversity in farm production. For instance, nearly 60% of all Alberta beef is fattened in southern Alberta's irrigated areas, creating employment and adding value to forage crop production. The estimated primary production impacts for 1999, that is, the increases compared to dryland agriculture of these 525,000 irrigated hectares, are shown in Table 25. The economic activity and impact on Alberta’s economy through primary production on irrigation district land is much greater than the area of irrigation would suggest. Although only about 4% of the crop land is irrigated, it generates more than 14% of the farm cash receipts, about 11% of the agricultural value-added, and 19% of direct agricultural employment.

Table 25. Primary production impacts of irrigation. Primary Benefits Incremental Impact Economic Activity (Irrigation minus Irrigation Dryland Dryland) Gross sales ($ millions) crops 298 59 239 livestock 562 78 484 Total 860 137 723 Value-added1 ($ millions) crops 163 31 132 livestock 95 16 79 Total 258 47 211 Employment2 crops 3,142 881 2,261 livestock 1,821 464 1,357 Total 4,963 1,345 3,618

1 Value-added is the return to labour, land, management and capital requirements. It is approximately the same as the computations underlying the Gross Domestic Product (Anderson 2000). 2 Full time equivalents.

140 2. Farm Supply Implications Compared to dryland agriculture, irrigation requires increased inputs and expenditures – fertilizers, pesticides, irrigation equipment and special crop harvesting equipment – to realize the primary benefits. These backward linkages generate economic activities that ripple through the economy to generate additional employment and income. Multipliers of primary benefits (scaling factors ) have been used to estimate the economic and employment impacts of irrigation backward linkages in 1999, as shown in Table 26.

3. Agri-processing Implications Irrigation also stimulates post-primary economic activities or forward linkages, such as storage, transportation, and processing. A 1996 profile of Alberta's rapidly growing agri-processing industry shows a $6.8 billion business with nearly 18,000 employees, a large meat and poultry component (33%), a beverages component (11%), dairy products and vegetables (each 9%), and flour products (8%). As these statistics show, in-province value-added processing of agricultural produce allows Albertans to capture additional income and employment from primary production, rather than exporting raw produce, as has been the predominant historical pattern. Agri-processing is largely concentrated in the irrigation-dependent southern part of the province. The ratio between the value of agri-processing shipments and farm receipts from primary production is 2.66 in the irrigated south, compared with 1.05 for other parts of Alberta. The socio-economic factors that make Alberta in general, and particularly the irrigated southern part of Alberta, attractive for agri-processing activities include: ! Adequate quantity and quality of water for the processing activity; ! Reliable supply of high quality raw material at a relatively low cost; ! Technologically advanced, skilled and motivated workers; ! Strong institutions focused on the environment and long-term sustainability; ! Proximity to markets; ! Excellent physical infrastructure (roads, power, water, natural gas); ! Excellent social infrastructure (schools, hospitals, recreational facilities, religious and cultural facilities); and ! Business-friendly tax structure and political and social environment. The estimated post-primary production impacts of 525,000 hectares of irrigated agriculture in 1999 are shown in Table 27.

Table 26. Multipliers of primary benefits. Backward Linkages Incremental Impact Economic Activity Irrigation minus Irrigation Dryland Dryland

Gross sales ($ millions) 860 137 723

Value-added ($ millions) 215 34 181

Employment (Full time equivalents) 2,150 343 1,807

141 Table 27. Post primary production impacts of irrigation. Forward Linkages Incremental Impact Economic Activity Irrigation minus Irrigation Dryland Dryland Gross sales ($ millions) 2,266 144 2,122 Value-added ($ millions) 574 38 536

Employment (full time equivalents) 5,971 308 5,663

4. Total Agricultural Impacts The total agricultural impacts of irrigation in 1999, both direct and indirect, are shown in Table 28. Note that the value-added estimate of $927 million approximates the incremental contribution of irrigation to the agri-food gross domestic product (GDP), considering primary production and both backward and forward linkages (AAFRD 2001/b). The 1999 agri-food GDP for all Alberta has been determined by AAFRD to be $4.52 billion, considering only primary production and forward linkages. In 1999, the incremental irrigation-based component represented about 16.5% of the agri-food GDP for all Alberta.

5. Non-agricultural Benefits of Irrigation Infrastructure In addition to direct and indirect agricultural benefits, irrigation provides significant benefits related to municipal and industrial water supplies, recreation and tourism, and wildlife. Municipal water use refers Irrigation development benefits municipalities and industries by ensuring to water diverted through the municipal water supplies, and by providing a means of disposing of waste water. works of a municipality for About 42,000 people in 47 southern Alberta communities rely on irrigation households, gardens and districts for their domestic water supplies – and the list is growing. Twelve major lawns, industry, commerce, industrial users, in addition to those within the communities, use water directly institutional, recreational from irrigation infrastructure. A number of communities and industries rely on and fire protection uses. effluent irrigation for disposal of their wastewater. Domestic water use refers Eighty-nine irrigation supported water bodies provide recreational activities in to private, individual southern Alberta. Recreational pursuits include water-based activities such as diversions for household use, boating, fishing, swimming and water skiing, as well as camping, hunting, and gardens and domestic animal wildlife watching and photography. There are seven provincial parks, 26 and poultry watering. Rural municipal parks and 13 day-use recreational areas on or near-by irrigation co-op projects also divert reservoirs or canals. User-days would total in the order of 400,000 per year. water for domestic use.

Table 28. Direct and indirect agricultural impacts of irrigation. Total Agricultural Benefits Incremental Impact Economic Activity Irrigation minus Irrigation Dryland Dryland

Gross sales ($ millions) 3,986 418 3,568 Value-added ($ millions) 1,047 120 927

Employment 13,084 1,996 11,088 (full time equivalents)

142 More than 20 irrigation reservoirs provide an estimated 250,000 angler-days of recreational fishing for species such as whitefish, northern pike and walleye. In addition, commercial fishing typically yields about 300 tonnes annually, valued at about $500,000. More than 35,000 hectares of wetland habitat has been created or enhanced by irrigation development. The wetlands provide habitat for a variety of waterfowl, shore birds, amphibians and reptiles, including several species of special concern due to declining populations. Improved upland habitat adjacent to the wetlands enhances conditions for foxes, weasels, badgers, sharp-tailed grouse, hawks, owls, deer, antelope and other wildlife. At least 60% of the province's pheasant population exists within the irrigation districts. Trail systems, such as the Kinbrook Marsh Nature Trail in the EID, are very popular for recreational and educational purposes. Recreational facilities in the irrigation areas also attract out-of-province visitors. It is estimated these tourists spend about $2 million a year on water- based recreation in southern Alberta. The monetary impact of recreational activities on the regional economy has been estimated to be in the order of $29 million a year. Other non-irrigation uses include water supplies for beef feedlots, stock watering and domestic uses, market gardens, golf courses, tree farms and sod farms. Irrigation works provide the source of domestic and stock water for at least 15 rural co-operative water supply projects.

C. OPPORTUNITIES FOR THE FUTURE In 1995, AAFRD challenged Alberta's agri-food sector to strive for $10 billion in primary production and $20 billion in value-added manufacturing by 2005. The Ministry retained Toma and Bouma Management Consultants to identify and explore various scenarios for meeting the challenge. The consultants concluded the primary production target could probably be achieved though a crop/livestock diversification strategy (Toma and Bouma Management Consultants 1997). Achieving the value-added processing target will be challenging and will require new ideas, new products and new businesses. The Alberta government, particularly AAFRD, has identified economic and job creation goals that generally focus on the need to add value to all raw material produced within the province (Alberta Treasury 1999; AAFRD 1999). An intensified and expanded irrigation industry is central to the successful execution of both a crop/livestock diversification strategy and an expanded value-added processing sector. Following is a brief overview of what is likely to evolve in the irrigation industry during the next 10 years, with and without expansion of the irrigated area from the current 525,000 hectares in the irrigation districts (Anderson 2000).

1. Livestock Additional beef production, beef finishing and slaughter operations in Alberta, and particularly southeastern Alberta, are expected to serve western Canada and, increasingly, the United States Pacific Northwest. A 50% increase in the meat processing industry in the irrigation-dependent south is expected by 2010. Feedlot capacity would also have to expand and become more dispersed. Forage production will continue to increase. Irrigated barley and corn silage are key feed ingredients for feedlots in southern Alberta. By 2010, it is expected the area of forage production will comprise almost one half of the irrigated land. This will result in a continual shift away from cereal grain crops.

143 2. Agri-processing Based on recent trends and discussions with practitioners in irrigation and agri-processing industries, projections for the future of value-added processing are as follows. ! The agri-processing sector in Alberta is expected to grow at about 4% a year. The growth rate in the irrigation areas is expected to be slightly higher. ! The irrigation sector currently accounts for about 30% of agri-processing shipments. This share is expected to climb to about 32% by 2010. The value-added component is expected to increase from a current 26% to 29%. Employment is expected to remain flat at about 30%. ! Vegetable processing in Alberta, which is tied to irrigation farm production, is expected to become more concentrated in the irrigated areas. ! Crop requirements for the agri-processing industry will increasingly impact on primary production patterns and marketing structure in irrigated areas. ! Producer/industry commodity contracts will become more common.

Ten-year projections of cropping implications for irrigated agriculture due to agri-processing initiatives include the following: ! The irrigated potato-growing area is expected to expand from the current 10,000 hectares to about 17,000 hectares; ! The sugar beet growing area is expected to expand to about 23,000 hectares from the current 17,000 hectares; ! Irrigated vegetable production will expand rapidly from 2,000 hectares to 8,000 hectares in response to demands by Lucerne, Bassano Growers and several other small processors; ! The area of pulse crop and forage seed production will likely increase significantly; ! Oilseed production, particularly canola, is expected to increase from the current 53,000 hectares to about 81,000 hectares; and ! Production of cereal crops will decrease, gradually shifting to grains that can be processed locally, for example, feed barley for the livestock industry and wheat for the flour milling industry (Ellison Milling Company). Virtually all the anticipated production shifts will reflect a trend to capture more value-added processing within Alberta. Land use intensity and input requirements will increase.

3. Impacts of Intensification and Expansion of Irrigation The impacts of intensification and two levels of potential expansion, 10% and 20%, are summarized in Tables 29 and 30. The 2005 and 2010 intensification scenarios (Table 29) track the economic impacts of a change in cropping patterns – particularly a shift from cereals to forage to support the livestock industry, and to specialty crops to support the agri-processing industry. By 2010, the total provincial value-added impact (direct and indirect) will be about $248 million, an increase of 27% from the current value-added contribution of irrigated agriculture. Employment would increase by almost 2,400 jobs, a gain of 21% over current irrigation-related employment. Irrigation expansion by 10% or 20% (Table 30) would have additional stimulative impacts on the Alberta economy. A 20% expansion by 2010 would approximately double the impact of the demand-driven crop production shifts, increasing the impact from 27% to 52% from current levels. The incremental

144 Table 29. Projected impacts of irrigation intensification.

Base Case Intensification Only - No Expansion 1999 - 525,000 ha. 2005 - 525,000 ha. 2010 - 525,000 ha. Economic Impacts Gross Value- Employ. Gross Value- Employ. Gross Value- Employ. Sales $M Added $M FTE Sales $M Added $M FTE Sales $M Added $M FTE

Direct (crops and livestock) 723 211 3,617 811 230 3,853 881 244 4,067 Backward links (suppliers) 723 181 1,807 811 203 2,026 881 220 2,203 Forward links (processors) 2,122 536 5,663 2,534 644 6,528 2,787 711 7,191 Total (direct and indirect) 3,568 927 11,088 4,155 1,078 12,407 4,550 1,175 13,461 Increase from 1999 Base Case 587 150 1319 982 248 2,374 Percent increase 16% 16% 12% 28% 27% 21%

Table 30. Projected impacts of irrigation intensification and expansion.

Base Case Intensification plus Intensification plus 1999 - 525,000 ha. 10% Expansion 20% Expansion 2005 - 579,000 ha 2010 - 632,000 ha

Gross Value- Employ. Gross Value- Employ. Gross Value- Employ. Sales $M Added $M FTE Sales $M Added $M FTE Sales $M Added $M FTE

Direct (crops and livestock) 723 211 3,617 892 253 4,239 1,058 293 4,881 Backward links (suppliers) 723 181 1,807 892 223 2,229 1,058 264 2,644 Forward links (processors) 2,122 536 5,663 2,788 709 7,181 3,345 853 8,629 Total (direct and indirect) 3,568 927 11,088 4,571 1,185 13,649 5,460 1,411 16,154 Increase from 1999 Base Case Intensification plus 10% expansion 1,003 258 2,562 Percent increase 28% 28% 23%

Intensification plus 20% expansion 1,892 483 5,067 Percent increase 53% 52% 46% Increase due to expansion only 10% expansion only 416 108 1,243 Percent increase 12% 12% 11%

20% expansion only 910 235 2,693 Percent increase 26% 25% 24%

Notes (Tables 29 and 30): ! All figures represent incremental values from dryland agriculture on the same areas. ! Value-added estimate (direct and indirect) is approximately equal to the contribution to the agri-food GDP. ! $M = millions of dollars. ! Employment based on 1 person-year per $100,000 in direct sales and assumes 1 Full Time Equivalency. ! FTE = 1880 person-hours. ! Expansion-only benefits based on difference between expansion plus intensification and intensification only.

145 value-added impact would climb to $483 million. To put the size of this impact into perspective, a value-added expansion of $483 million would represent an approximate 10% increase in the total Alberta agri-food GDP. Total direct and indirect employment increases would be in excess of 5,000 person-years. The indirect impacts would increase at an even greater rate than the primary production impacts of irrigation.

D. CONCLUSIONS The following conclusions have been drawn from the Irrigation Water Management Study on the potential benefits of irrigation development.

Irrigation intensification and expansion will contribute positively to Alberta’s agri-food strategy and the province’s social and economic objectives. For example, the agricultural development strategy in Alberta calls for livestock diversification and growth, which in turn is dependent on increased forage production and an assured and adequate supply of water. The irrigated southern portion of the province has high potential to supply both the water and forage needs for an expanded livestock industry. Irrigation also contributes to sustaining the province’s agricultural resource base by increasing the productivity of the land by 250% to 300%. The simulation modelling in the Irrigation Water Management Study indicates that intensification alone will increase irrigation-related agri-processing by 32%–– from $536 million to $711 million by the year 2010. A 20% expansion of irrigation area would increase agri-processing by about 60%, to $853 million.

To be successful in meeting the province’s growth targets for the agri- food processing industry, a disproportionate amount of growth must take place in the irrigated south. The irrigated region has the longest growing season, combined with high heat units and relatively secure water supply. This can provide stable, high quality production of value-added crops.

Expansion and intensification of irrigation in southern Alberta will continue to improve the sustainability of the family farm and contribute to the economic and social well-being of its rural communities. The trend toward consolidation of farming enterprises, increased input costs and reduced profit margins poses a threat to the family farm business and the sustainability of rural communities. Irrigation improves the long-term sustainability of smaller farm units by increasing yields, facilitating the growth of a wider variety of higher value crops, and reducing financial risks. The need for irrigation supplies and services supports rural agri- business enterprises. Higher labour requirements for primary production on irrigated land increase rural populations and contribute to more vibrant communities and greater infrastructure development.

146 Expansion within the context of conservation safeguards already in place or being developed will also benefit wildlife and the environment. The irrigation industry has become increasingly aware of the need to be responsible stewards of land and water resources and is working– both as an industry and as individuals– toward sustainable growth. For example, the control of canal seepage has helped reduce soil salinity. Water management and conservation have helped develop and sustain wetland habitat crucial to birds and other wildlife.

Innovation, research and improved technology will continue to be critical components of agricultural growth and will add to long-term success in primary production and value-added processing. Innovation and research have brought new ideas, new resources and greater potential for economic synergies to the agricultural industry, including the establishment or expansion of several multi-national agri-processors in the irrigated south. Potential for similar growth in the future is excellent.

147 References REFERENCES

AgSummit. 2000. What's Happened So Far? Alberta Agriculture, Food and Rural Development. Edmonton, AB.

Alberta Agriculture. 1990. Irrigation Water Requirements for Alberta Irrigation Districts. Irrigation Branch. Lethbridge, AB.

Alberta Agriculture, Food and Rural Development (AAFRD). 1999. 1999 - 2002 Business Plan. Edmonton. AB.

Alberta Agriculture, Food and Rural Development (AAFRD). 2001/a. Alberta Irrigation Districts Crop and Water Information 2000. Irrigation Branch. Lethbridge. AB.

Alberta Agriculture, Food and Rural Development (AAFRD). 2001/b. Alberta Agri-Food Key Stats. Statistics and Data Development. Edmonton, AB.

Alberta Environment (AENV). 1984. South Saskatchewan River Basin Planning Program – Summary Report. Alberta Environment. Edmonton, AB.

Alberta Environment (AENV). 1989. Multiple Use of Irrigation Systems. Alberta Environment, Planning Division. Edmonton, AB.

Alberta Environment (AENV). 1990. South Saskatchewan River Basin Water Management Policy. Planning Division. Edmonton, AB.

Alberta Environment (AENV). 1991. South Saskatchewan Basin Water Allocation Regulation. Edmonton, AB.

Alberta Treasury. 1999. Measuring Up ‘98. Communications. Edmonton, AB.

Alberta Water Resources Commission. 1986. Water Management in the South Saskatchewan River Basin – Report and Recommendations. Alberta Environment. Edmonton, AB.

Anderson, M. S. 2000. The Benefits of Irrigation in Southern Alberta in the Year 2000 and Beyond. Alberta Agriculture, Food and Rural Development, Irrigation Branch. Lethbridge, AB.

Dennis, J.S. 1894. Letter Report on Irrigation Development and Water Rights Legislation. Provincial Archives of Alberta. Edmonton, AB.

Filion, Y. 2000. Climate Change: Implications for Canadian Water Resources and Hydropower Production. Canadian Water Resources Journal, Volume 25, No. 3.

Foroud, N. and E.H. Hobbs. 1983. The LETHIRR Irrigation Scheduling Model – Description and Operating Procedures. Agriculture Canada, Research Branch. Lethbridge, AB.

Klemes, V. 1990. Sensitivity of Water Resource Systems to Climate Variability. Proceedings of the Canadian Water Resources Association 43rd Annual Conference. Penticton, BC.

151 Klemes, V. 1991. Design Implications of Climate Change. Proceedings of First National Conference on Climate Change and Water Resource Management. IWR Report 93-R-17. US Army Corps of Engineers. National Technical Information Services. Springfield, Virginia.

Krogman, K.K. and E.H. Hobbs. 1966. A Comparison of Measured and Calculated Evapotranspiration for Alfalfa in Southern Alberta. Canadian Agricultural Engineering. Volume 8, No. 1.

Morton, F.I. 1968. Evaporation and Climate – A Study in Cause and Effect. Inland Waters Branch, Environment Canada. Ottawa, ON.

MPE Engineering Ltd. 1997. Year 2000 Data Analysis – Standards for Return Flow Data Collection. Irrigation Branch, AAFRD. Lethbridge, AB.

Muzik, I. 2001. Sensitivity of Hydrologic Systems to Climate Change. Canadian Water Resources Journal, Volume 26, No. 2.

National Task Force on the Environment and Economy. 1987. Report of the National Task Force on the Environment and Economy. Report to the Canadian Council of Resource and Environment Ministers. Environment Canada. Ottawa, ON.

Olson, B.M., G.H. Dill, R.V. Riewe, S.N. Acharya, T.E. Harms and L. Morrison. 2000. Effect of Cutting, Irrigation Management, and Water Availability on the Water Use of Alfalfa – 1999 Progress Report. Irrigation Branch, AAFRD. Lethbridge, AB.

Peters, F.H. 1912. Report on Irrigation and Irrigation Surveys. Department of the Interior Annual Report on Irrigation. Environment Canada. Calgary, AB.

Prairie Provinces Water Board (PPWB). 1995. Assessment of Natural Flow Computation Procedures and Monitoring Network for Administering Apportionment of the South Saskatchewan River Basin at the Alberta- Saskatchewan Boundary. PPWB Report No. 133. Regina, SK.

Rogers, W.B., T.W. Manning and H.W. Grubb. 1966. The Economic Benefits and Costs of Irrigation in the Eastern Irrigation District in Alberta. University of Alberta. Edmonton, AB.

Sauchyn, D.J. 1997. Proxy Records of Post-Glacial Climate in the Canadian Prairie Provinces: A Guide to the Literature and Current Research. Department of Geography, University of Regina. Regina. SK.

Sonmor, L.G. 1963. Seasonal Consumptive Use of Water by Crops Grown in Southern Alberta and its Relationship to Evaporation. Canadian Journal of Soil Science, Volume 43.

Toma and Bouma Management Consultants. 1997. A Sustainable Growth Strategy for the Agri- Food Sector. Alberta Agriculture, Food and Rural Development. Edmonton, AB.

152 Appendix Appendix

SUPPORTING DATA Information for Tables A-1 through A-6 was derived as part of the Irrigation Water Management Study and is included on the following pages as supporting data. Table A-1 provides the Prairie Provinces Water Board return flow estimates used in compiling data on water losses. Table A-2 presents a summary look at agro-climatic and crop type data used in the Farm Financial Impact and Risk Model. Tables A-3 through A-6 present irrigation water demand and deficit analyses used in the Irrigation District Model and/or the Water Resources Management Model.

DETAILED ASSESSMENT OF EXPANSION SCENARIOS

A total of 10 irrigation scenarios was modelled as part of the Irrigation Water Management Study. Details on four key scenarios are given in the body of this volume. Histograms showing the variation in weighted-average irrigation demand, bar graphs showing the frequency of irrigation deficits, and line graphs showing the areal extent of irrigation deficits modelled for the other six scenarios are presented here (Figures A-1a through A-12b). As in Chapter VI, distinct graphics are shown for the Bow Basin districts and the Oldman Basin districts.

155 10,303

11,300

89,425

76,137

32,036

Mean

240,341

115,424

574,966

2000

77,423

67,215

26,678

77,319

22,516

35,500

210,648

517,299

95,593

81,885

41,428

72,439

13,419

10,644

199,406

514,814

9,297

5,482

76,451

39,905

93,647

614,593

250,195

139,616

7,141

9,002

77,322 90,322

35,600

594,215

103,488

271,340

7,181

9,694

80,138

38,502

73,026

142,889

243,952

595,382

3,641

3,276

32,273

67,262

69,880

116,708

270,647

563,687

) from 1985 to 2000

8,448

7,506

99,395

38,580

62,350

and MID together

239,913

117,397

573,589

4,021

2,822

72,881

28,669

101,125

202,002

162,054 573,574

38,051

15,755

13,166 87,916

675,633

114,167

121,968

284,610

eturn flow estimates (dam

7,587

9,000

70,910

37,734

127,623

105,100 269,340

627,294

7,337

6,184

73,545

93,789

31,642

.Eng., PPWB.

561,058

246,869

101,692

7,999

25,081

89,901

62,643

11,290

525,851

227,387

101,550

Water Survey of Canada provisional data.

17,891

19,175

77,296

27,234

103,111

101,597

202,382

548,686

ovinces Water Board (PPWB) r

AID.

TID. The PPWB estimates the total return flow from SMP

66,447

12,899

26,530

84,284 14,574

211,448

116,932

533,114

9,602

21,983

11,409

92,459

82,440

632,658

263,619

151,146

13,867

1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999

16,196 14,806

84,284

98,864 68,284

251,709

548,010

MID

BRID SMP, UID Totals EID LNID WID MVLA

Highlighted data computations based on PPWB equations and methodology MVLA includes MVID, LID and For the WID, April data are excluded from the estimates. SMP includes SMRID, RID and

All 1993 to 2000 data obtained directly from Jim Chen, P

All 1985 to 1992 data, except highlighted data, taken from PPWB report (PPWB 1995).

Some return flow estimates may be based on

Table A-1. Summary of Prairie Pr

156 25

Potato

Dry

Beans

Beets

Sugar

20 20

30 25

25 30

30 25 40

40 40

30 25

Barley Canola

ea)

20 20

20 25 25

20 20 25

Soft

Wheat

20 20 20 20

Wheat

Durum

Crops (% of farm ar

ed in the FFIRM analysis.

HRS

Wheat

15 30 30 30 30

Tame

Grass

Silage

Barley

30 35

25 40 30 30 30 25 40 30 35

Alfalfa

farm enterprise types consider

Type

op regions for

Farm Enterprise

B1 Grain and oilseed mix B3 Potato mix B2 Sugar beet mix B4 Forage mix R1 Grain and oilseed mix R2 Grain and forage mix L3 Grain and forage mix E1 Grain and oilseed mix S2 Forage mix R3 Forage mix L1 Grain and oilseed mix L4 Forage mix E2 Sugar beet mix S1 Grain and forage mix U2 Forage mix U1 Grain and forage mix 25 L2 Sugar beet mix E3 Potato mix E4 Forage mix

Climate and Crop Region

Lethbridge area LNID RID SMRID-W -300 ha farm unit

Enchant area UID/MID area Rosemary area Burdett area BRID -225 ha farm unit Strathmore area WID-E TID EID-S WID-W EID-N SMRID-E -325 ha farm unit -360 ha farm unit -220 ha farm unit -325 ha farm unit

Table A-2. Agro-climatic and cr

157 380 526 369 446 507 374 431 530 444 348 475 357 405 491 334 417 444 343 383 459 367 395 514 360 433 496 354 421 483 412

f from irrigated

Demand

dam

1,021,552 1,165,466 1,093,089 2,187,018 1,212,592 1,107,900 2,305,681 1,267,601 2,375,501 1,133,968 1,249,659 1,163,295 2,383,627 1,291,752 1,088,349 2,455,047 1,168,102 1,219,283 2,256,451 1,317,344 1,195,881 2,536,627 1,352,262 1,173,071 2,548,143 1,304,907 1,258,385 2,477,978 1,386,224 2,644,609

Gross Diversion

64 58 55

86 53 54 91 49 92 50 84 51 84 46 80 43 72 98 68

116

164 109 153 100 125

137 138 128 127

105

available supply sources.

rop water requirements.

434,118

171,070 364,350 171,813 535,420 365,930 162,927 537,743 298,963 461,890 172,702 360,428 175,961 533,130 363,059 159,668 539,020 336,750 177,738 496,418 364,494 166,185 542,232 305,180 149,892 471,365 276,240 152,855 426,132 281,263

Return Flow

dam

e base flow and/or recaptured runof

ation received during the growing season and stored soil

ce system tail-water not returned to a river or creek, but is lost to

41 77 38 57 72 37 53 72 53 34 65 34 48 66 33 48 63 32 46 60 34 45 66 33 48 64 30 47 59 43

Losses

112,567

110,790 110,790 113,752 110,790

109,009 169,976 278,985 172,202 109,605 284,769 172,202 281,807

171,006 281,796 173,637 107,531 284,427 165,744 273,276 172,202 285,954 173,637 107,531 284,427 168,375 106,643 275,906 169,332 275,975

dam

District Infrastructur

all scenarios.

73 74 72 73 73 62 72 71 66 58 58 60 58 61 50 60 48 58 49 58 62 58 71 56 66 62 56 59 62 59

169,811

163,113

195,749 162,952 213,286 358,701 174,594 183,663 387,880 353,474 188,995 152,590 195,512 341,585 160,482 162,927 355,994 126,281 206,176 289,208 166,462 202,029 372,638 186,791 182,478 388,820 199,067 345,591 177,942 377,009

dam

On-Farm Losses

f or deep percolation during the irrigation water application process at the farm level.

limit area; E1 = 10% area expansion; E2 = 20% area expansion; C0 = 1999 crop mix; C2 = future crop mix;

211

203 201 207 209 220 205 262 239 203 215 209 208 226 202 217 205 203 203 214 220 208 261 225 238 265 225 243 264 242

weighted-mean values for

Regulation

545,724 468,188 595,422 499,865 651,706 626,625 661,482 565,635

681,033 594,574 658,223 539,326 721,616 614,186 716,877 686,654 733,169 697,178 799,821 757,688

dam

1,227,117

Requirement

1,013,912 1,095,287 1,278,331

1,275,607 1,197,549 1,335,802 1,403,531 1,430,347 1,557,509

Crop Irrigation

(ha)

Area

268,859 221,526 296,230 490,385 239,170 296,230 535,400 239,170 325,853 535,400 263,086 588,939 325,853 263,086 325,853 588,939 263,086 355,476 588,939 287,003 325,853 642,479 263,086 325,853 588,939 263,086 355,476 588,939 287,003 642,479

Irrigated

Oldman Bow Oldman All Districts Bow Oldman All Districts Bow Oldman All Districts Bow All Districts Oldman Bow Oldman All Districts Bow Oldman All Districts Bow Oldman All Districts Bow Oldman All Districts Bow Oldman All Districts Bow All Districts

6 6 6 6 6 6 6

6 6 6

Scenario Basin

S1. S2. S3. S4. S5. S6. S7. S8. S9. S10. S0C0M0P8 S9C0M0P8 S9C0M0P9 E1C0M0P8 E1C2M0P8 E1C0M2P8 E2C0M0P8 E1C0M0P9 E1C2M2P9 E2C2M2P9

moisture consumed.

end-of-system ponding and/or evaporation.

fields, all of which is drained back to rivers and creeks in the area.

M0 = 1999 irrigation system mix; M2 = future irrigation system mix; P8 = irrigation to meet 80% of crop water requirements; P9 = irrigation to meet 90% of c

On-farm Losses is that amount of water lost due to evaporation, un-captured runof District Infrastructure Losses includes that volume of water lost due to canal seepage, open-channel and reservoir evaporation, as well as conveyan

Return Flow is that quantity of water that flows through a conveyance system that is composed of unused water from on-farm system downtime, unavailabl

Identifies scenario parameter settings. S0 = 1999 irrigation area; S9 =

The Gross Diversion Demand is the sum of the four components defined above and is that total volume of water demanded by weighted average, each year from

The Crop Irrigation Requirement is the net amount of water required for the crop growing season to be available for crop consumption, less any precipit

Table A-3. Summary of modelling output, 68-year

158 524

454

572

341

475

233

389

382

548

446

Demand

3,295

dam

13,780

28,714

26,980

363,708

638,971

202,346

746,436

162,788

Gross Diversion

2,187,017

11.9

53.4

32.6

27.4

24.0

45.7

35.8

45.4

43.2

24.4

%ofGD

280

148

157

217

174

237

109

Return Flow

7,363

1,179

dam

13,118

48,658

88,495

12,257

70,403

118,565

175,382

535,420

5.5

7.7

7.9

7.0

11.3

17.7

18.5

10.8

17.9

12.8

e Losses

%ofGD

101

TID, all served by a common main canal carrier and therefore are

763

355

weighted-average .

5,320

1,902

dam

29,112

28,039

16,022

84,647

112,825

District Infrastructur

278,984

9.7

12.8

15.6

13.8

18.2

19.0

20.1

13.8

10.9

16.4

, this volume of loss also includes reservoir evaporation for those reservoirs owned and

%ofGD

eakdown of 68-year

Where such internal reservoir storage is shared between two or more districts, the reservoir evaporation

AID and LID which are both served by a common main canal carrier and therefore are modelled as one

On-Farm Losses

625

1,762

2,781

3,734

dam

56,879

88,249

36,790

17,824

150,057

358,700

ement

28.2

44.1

41.1

49.9

26.1

34.5

56.7

33.7

27.9

46.4

%ofGD

Scenario S1, district br

148

200

235

170

124

220

129

153

207

3,892

7,496

1,136

9,087

45,450

dam

160,224

262,514

100,876

423,237

1,013,912

Crop Irrigation Requir

2,630

6,045

1,420

7,044

80,112

59,339

29,706

111,708

Hectares

192,381

490,385

Irrigated

(St. Mary Project) represents a “virtual” single district made up of the RID, SMRID, and

operated within the works of respective irrigation districts. losses are pro-rated between these supported districts, according to their“virtual” respective district. irrigated areas.

modelled as one “virtual” district.

AID_LID

BRID

EID

LNID

MID

MVID

SMP

UID

WID

Total

Weighted Mean

Irrigation District

% of GD = Percent of Gross Diversion (Demand). In addition to canal seepage and evaporation losses and un-captured tail-water

The AID_LID represents a “virtual” single district made up of the

The SMP

Table A-4. IDM modelling output for

159 1

1.2

3.5

3.8

5.0

6.3

2.0

9.0

7.8

6.8

10.0

Mean Rank

Rank

0.00

0.04

0.08

0.34

0.00

0.83

0.59

0.22

1.09

>250 mm

Rank

0.00

0.18

0.39

0.95

0.08

1.20

0.98

1.01

1.58

Rank

0.01

0.71

0.69

1.22

1.82

0.36

2.61

2.03

1.86

4.38

>150 mm >200 mm

Various Magnitudes; Rank among all Scenarios

Rank

0.14

2.32

2.40

3.66

5.37

1.69

6.95

6.28

4.54

8.67

>100 mm

limit area; E1 = 10% area expansion; E2 = 20% area expansion; C0 = 1999 crop mix;

Rank

1.3

irrigation districts in the Oldman Basin.

>50 mm

6.17

6.81

8.60

9.67

5.99

11.29

10.86

10.21

12.24

Regulation

Percent of Years with Deficits of

Rank

>1.0 mm

9.68

20.67

18.29

21.42

23.74

17.40

30.93

28.09

24.58

35.48

Rank

Demand

dam

Gross Diversion

1,021,552

1,093,089

1,107,900

1,133,968

1,163,295

1,088,349

1,219,283

1,195,881

1,173,071

1,258,385

C2 = future crop mix; M0 = 1999 irrigation system mix; M2 = future irrigation system mix; P8 = irrigation to meet 80% of crop water requirements; P9 = irrigation to meet 90% of crop water requirements.

f 1 = Lowest level of deficits. Rank of 10 = Highest level of deficits.

S1. S0C0M0P8 Scenario S2. S9C0M0P8

S3. S9C0M0P9

S4. E1C0M0P8

S5. E1C2M0P8

S6. E1C0M2P8

S7. E2C0M0P8

S8. E1C0M0P9

S9. E1C2M2P9

S10. E2C2M2P9

Rank o Identifies scenario parameter settings. S0 = 1999 irrigation area; S9 =

Table A-5. Ranking of IDM-WRMM modelling deficit indices for

160 3

1.4

6.8

3.6

5.0

2.2

5.6

9.4

6.4

9.6

Mean Rank

Rank

0.00

0.04

0.00

0.04

0.00

>250 mm

Rank

0.00

0.16

0.04

0.00

0.04

0.44

0.13

0.22

Rank

0.03

0.71

0.44

0.67

0.17

0.67

0.79

0.68

0.79

>150 mm >200 mm

Various Magnitudes; Rank among all Scenarios

Rank

limit area; E1 = 10% area expansion; E2 = 20% area expansion;

0.24

1.97

1.01

1.39

0.69

1.53

2.66

1.83

2.51

>100 mm

Rank

Regulation

irrigation districts in the Bow Basin.

>50 mm

0.95

5.01

4.44

5.08

2.58

5.31

6.49

5.30

7.03

Percent of Years with Deficits of

Rank

>1.0 mm

7.67

16.11

14.76

14.47

15.79

12.34

16.61

17.92

19.27

Rank

Demand

dam

Gross Diversion

1,165,466

1,212,592

1,267,601

1,249,659

1,291,752

1,168,102

1,317,344

1,352,262

1,304,907

1,386,224

f 1 = Lowest level of deficits. Rank of 10 = Highest level of deficits.

C0 = 1999 crop mix; C2 = future crop mix; M0 = 1999 irrigation system mix; M2 = future irrigation system mix; P8 = irrigation to meet 80% of crop water requirements; P9 = irrigation to meet 90% of crop water requirements.

S1. S0C0M0P8 Scenario S2. S9C0M0P8

S3. S9C0M0P9

S4. E1C0M0P8

S5. E1C2M0P8

S6. E1C0M2P8

S7. E2C0M0P8

S8. E1C0M0P9

S9. E1C2M2P9

S10. E2C2M2P9

Rank o Identifies scenario parameter settings. S0 = 1999 irrigation area; S9 =

Rank for deficit class >250 not included in the mean due to the number of scenarios with equal deficit probabilities.

Table A-6. Ranking of IDM-WRMM modelling deficit indices for

161 900

800 Deficit Demand Regulation licence depth per unit area Weighted-average demand for all years 700

600

verage 500

400

Weighted-A 300

Irrigation Demand and Deficit (mm) 200

100

1928

1933

1938

1943

1948

1953

1958

1963

1968

1973

1978

1983

1988

1993

Irrigation area = 1991Regulation limit. All other variables at 1999 conditions.

Figure A-1a. Scenario S2 total demands and deficits - Bow Basin districts.

30 70 Deficit Frequency Areal Extent of Deficits 25 60 1-50 mm 50 51-100 mm 20 101-150 mm 40 151-200 mm 15 201-250 mm 30 251+ mm 10 20

5 No. of Years10 Out of 68

Frequency of Occurrence (%) 0 0 1-50 51 - 100 101 - 150 151 - 200 201 - 250 > 250 1-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 > 80 Deficit Range (mm) Portion of Basin Affected (%)

Figure A-1b. Scenario S2 irrigation deficit frequency and distribution - Bow Basin districts.

162 900

800 Deficit Demand Regulation licence depth per unit area 700 Weighted-average demand for all years

600

verage 500

400

Weighted-A 300

Irrigation Demand and Deficit (mm) 200

100

1928

1933

1938

1943

1948

1953

1958

1963

1968

1973

1978

1983

1988

1993

Irrigation area = 1991Regulation limit. All other variables at 1999 conditions.

Figure A-2a. Scenario S2 total demands and deficits - Oldman Basin districts.

30 70 Deficit Frequency Areal Extent of Deficits 25 60 1-50 mm 50 51-100 mm 20 101-150 mm 40 151-200 mm 15 201-250 mm 30 251+ mm 10 20

5 No. of Years10 Out of 68

Frequency of Occurrence (%) 0 0 1-50 51 - 100 101 - 150 151 - 200 201 - 250 > 250 1-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 > 80 Deficit Range (mm) Portion of Basin Affected (%)

Figure A-2b. Scenario S2 irrigation deficit frequency and distribution - Oldman Basin districts.

163 900

Deficit Demand 800 Regulation licence depth per unit area Weighted-average demand for all years 700

600

verage 500

400

Weighted-A 300

Irrigation Demand and Deficit (mm) 200

100

1928

1933

1938

1943

1948

1953

1958

1963

1968

1973

1978

1983

1988

1993

10% expansion beyond 1991Regulation limit. All other variables at 1999 conditions.

Figure A-3a. Scenario S4 total demands and deficits - Bow Basin districts.

30 70 Deficit Frequency Areal Extent of Deficits 25 60 1-50 mm 50 51-100 mm 20 101-150 mm 40 151-200 mm 15 201-250 mm 30 251+ mm 10 20

5 No. of Years10 Out of 68

Frequency of Occurrence (%) 0 0 1-50 51 - 100 101 - 150 151 - 200 201 - 250 > 250 1-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 > 80 Deficit Range (mm) Portion of Basin Affected (%)

Figure A-3b. Scenario S4 irrigation deficit frequency and distribution - Bow Basin districts.

164 900

800 Deficit Demand Regulation licence depth per unit area 700 Weighted-average demand for all years

600

verage 500

400

Weighted-A 300

Irrigation Demand and Deficit (mm) 200

100

1928

1933

1938

1943

1948

1953

1958

1963

1968

1973

1978

1983

1988

1993

10% expansion beyond 1991Regulation limit. All other variables at 1999 conditions.

Figure A-4a. Scenario S4 total demands and deficits - Oldman Basin districts.

30 70 Deficit Frequency Areal Extent of Deficits 25 60 1-50 mm 50 51-100 mm 20 101-150 mm 40 151-200 mm 15 201-250 mm 30 251+ mm 10 20

5 No. of Years10 Out of 68

Frequency of Occurrence (%) 0 0 1-50 51 - 100 101 - 150 151 - 200 201 - 250 > 250 1-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 > 80 Deficit Range (mm) Portion of Basin Affected (%)

Figure A-4b. Scenario S4 irrigation deficit frequency and distribution - Oldman Basin districts.

165 900 Deficit Demand 800 Regulation licence depth per unit area Weighted-average demand for all years 700

600

verage 500

400

Weighted-A 300

Irrigation Demand and Deficit (mm) 200

100

1928

1933

1938

1943

1948

1953

1958

1963

1968

1973

1978

1983

1988

1993

10% expansion beyond 1991Regulation limit, plus crop mix shift. All other variables at 1999 conditions.

Figure A-5a. Scenario S5 total demands and deficits - Bow Basin districts.

30 70 Deficit Frequency Areal Extent of Deficits 25 60 1-50 mm 50 51-100 mm 20 101-150 mm 40 151-200 mm 15 201-250 mm 30 251+ mm 10 20

5 No. of Years10 Out of 68

Frequency of Occurrence (%) 0 0 1-50 51 - 100 101 - 150 151 - 200 201 - 250 > 250 1-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 > 80 Deficit Range (mm) Portion of Basin Affected (%)

Figure A-5b. Scenario S5 irrigation deficit frequency and distribution - Bow Basin districts.

166 900

800 Deficit Demand Regulation licence depth per unit area 700 Weighted-average demand for all years

600

verage 500

400

Weighted-A 300

Irrigation Demand and Deficit (mm) 200

100

1928

1933

1938

1943

1948

1953

1958

1963

1968

1973

1978

1983

1988

1993

10% expansion beyond 1991Regulation limit, plus crop mix shift. All other variables at 1999 conditions.

Figure A-6a. Scenario S5 total demands and deficits - Oldman Basin districts.

30 70 Deficit Frequency Areal Extent of Deficits 25 60 1-50 mm 50 51-100 mm 20 101-150 mm 40 151-200 mm 15 201-250 mm 30 251+ mm 10 20

5 No. of Years10 Out of 68

Frequency of Occurrence (%) 0 0 1-50 51 - 100 101 - 150 151 - 200 201 - 250 > 250 1-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 > 80 Deficit Range (mm) Portion of Basin Affected (%)

Figure A-6b. Scenario S5 irrigation deficit frequency and distribution - Oldman Basin districts.

167 900 Deficit Demand 800 Regulation licence depth per unit area Weighted-average demand for all years 700

600

verage 500

400

Weighted-A 300

Irrigation Demand and Deficit (mm) 200

100

1928

1933

1938

1943

1948

1953

1958

1963

1968

1973

1978

1983

1988

1993

10% expansion beyond 1991Regulation limit, plus system mix shift. All other variables at 1999 conditions.

FigureA-7a. Scenario S6 total demands and deficits - Bow Basin districts.

30 70 Deficit Frequency Areal Extent of Deficits 25 60 1-50 mm 50 51-100 mm 20 101-150 mm 40 151-200 mm 15 201-250 mm 30 251+ mm 10 20

5 No. of Years10 Out of 68

Frequency of Occurrence (%) 0 0 1-50 51 - 100 101 - 150 151 - 200 201 - 250 > 250 1-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 > 80 Deficit Range (mm) Portion of Basin Affected (%)

Figure A-7b. Scenario S6 irrigation deficit frequency and distribution - Bow Basin districts.

168 900

800 Deficit Demand Regulation licence depth per unit area 700 Weighted-average demand for all years

600

verage 500

400

Weighted-A 300

Irrigation Demand and Deficit (mm) 200

100

1928

1933

1938

1943

1948

1953

1958

1963

1968

1973

1978

1983

1988

1993

10% expansion beyond 1991Regulation limit, plus system mix shift. All other variables at 1999 conditions.

Figure A-8a. Scenario S6 total demands and deficits - Oldman Basin districts.

30 70 Deficit Frequency Areal Extent of Deficits 25 60 1-50 mm 50 51-100 mm 20 101-150 mm 40 151-200 mm 15 201-250 mm 30 251+ mm 10 20

5 No. of Years10 Out of 68

Frequency of Occurrence (%) 0 0 1-50 51 - 100 101 - 150 151 - 200 201 - 250 > 250 1-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 > 80 Deficit Range (mm) Portion of Basin Affected (%)

Figure A-8b. Scenario S6 irrigation deficit frequency and distribution - Oldman Basin districts.

169 900

Deficit Demand 800 Regulation licence depth per unit area Weighted-average demand for all years 700

600

verage 500

400

Weighted-A 300

Irrigation Demand and Deficit (mm) 200

100

1928

1933

1938

1943

1948

1953

1958

1963

1968

1973

1978

1983

1988

1993

20% expansion beyond 1991Regulation limit. All other variables at 1999 conditions.

Figure A-9a. Scenario S7 total demands and deficits - Bow Basin districts.

30 70 Deficit Frequency Areal Extent of Deficits 25 60 1-50 mm 50 51-100 mm 20 101-150 mm 40 151-200 mm 15 201-250 mm 30 251+ mm 10 20

5 No. of Years10 Out of 68

Frequency of Occurrence (%) 0 0 1-50 51 - 100 101 - 150 151 - 200 201 - 250 > 250 1-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 > 80 Deficit Range (mm) Portion of Basin Affected (%)

Figure A-9b. Scenario S7 irrigation deficit frequency and distribution - Bow Basin districts.

170 900

800 Deficit Demand Regulation licence depth per unit area 700 Weighted-average demand for all years

600

verage 500

400

Weighted-A 300

Irrigation Demand and Deficit (mm) 200

100

1928

1933

1938

1943

1948

1953

1958

1963

1968

1973

1978

1983

1988

1993

20% expansion beyond 1991Regulation limit. All other variables at 1999 conditions.

Figure A-10a. Scenario S7 total demands and deficits - Oldman Basin districts.

30 70 Deficit Frequency Areal Extent of Deficits 25 60 1-50 mm 50 51-100 mm 20 101-150 mm 40 151-200 mm 15 201-250 mm 30 251+ mm 10 20

5 No. of Years10 Out of 68

Frequency of Occurrence (%) 0 0 1-50 51 - 100 101 - 150 151 - 200 201 - 250 > 250 1-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 > 80 Deficit Range (mm) Portion of Basin Affected (%)

Figure A-10b. Scenario S7 irrigation deficit frequency and distribution - Oldman Basin districts.

171 900 Deficit Demand 800 Regulation licence depth per unit area Weighted-average demand for all years 700

600

verage 500

400

Weighted-A 300

Irrigation Demand and Deficit (mm) 200

100

1928

1933

1938

1943

1948

1953

1958

1963

1968

1973

1978

1983

1988

1993

10% expansion beyond 1991Regulation limit plus near-optimum irrigation level. All other variables at 1999 conditions.

Figure A-11a. Scenario S8 total demands and deficits - Bow Basin districts.

30 70 Deficit Frequency Areal Extent of Deficits 25 60 1-50 mm 50 51-100 mm 20 101-150 mm 40 151-200 mm 15 201-250 mm 30 251+ mm 10 20

5 No. of Years10 Out of 68

Frequency of Occurrence (%) 0 0 1-50 51 - 100 101 - 150 151 - 200 201 - 250 > 250 1-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 > 80 Deficit Range (mm) Portion of Basin Affected (%)

Figure A-11b. Scenario S8 irrigation deficit frequency and distribution - Bow Basin districts.

172 900

800 Deficit Demand Regulation licence depth per unit area 700 Weighted-average demand for all years

600

verage 500

400

Weighted-A 300

Irrigation Demand and Deficit (mm) 200

100

1928

1933

1938

1943

1948

1953

1958

1963

1968

1973

1978

1983

1988

1993

10% expansion beyond 1991Regulation limit plus near-optimum irrigation level. All other variables at 1999 conditions.

Figure A-12a. Scenario S8 total demands and deficits - Oldman Basin districts.

30 70 Deficit Frequency Areal Extent of Deficits 25 60 1-50 mm 50 51-100 mm 20 101-150 mm 40 151-200 mm 15 201-250 mm 30 251+ mm 10 20

5 No. of Years10 Out of 68

Frequency of Occurrence (%) 0 0 1-50 51 - 100 101 - 150 151 - 200 201 - 250 > 250 1-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 > 80 Deficit Range (mm) Portion of Basin Affected (%)

Figure A-12b. Scenario S8 irrigation deficit frequency and distribution - Oldman Basin districts.

173 Acronyms used in this volume

AAFC - Agriculture and Agri-Food Canada AAFRD - Alberta Agriculture, Food and Rural Development AENV - Alberta Environment AID - Aetna Irrigation District AIPA - Alberta Irrigation Projects Association BRID - Bow River Irrigation District EID - Eastern Irrigation District FFIRM - Farm Financial Impact and Risk Model GDP - Gross Domestic Product GIS - Geographic Information System GRIPCD - Gridded Prairie Climate Database IDM - Irrigation District Model LID - Leavitt Irrigation District LNID - Lethbridge Northern Irrigation District LRSIMM - Lethbridge Research Station Irrigation Management Model MID - Magrath Irrigation District MVID - Mountain View Irrigation District NFI - Net Farm Income PFRA - Prairie Farm Rehabilitation Administration PPWB - Prairie Provinces Water Board RID - Raymond Irrigation District SMP - St. Mary Project (SMRID, RID and TID combined) SMRID - St. Mary River Irrigation District SSRB - South Saskatchewan River Basin TID - Taber Irrigation District UID - United Irrigation District WID - Western Irrigation District WRMM - Water Resources Management Model

175