Lead authors:
Whitney R. Lonsdale, Montana Water Center, Montana State University, Bozeman, MT 59717
Wyatt F. Cross, Montana Water Center, Montana State University, Bozeman, MT 59717
Contributing authors:
Charles E. Dalby, Kintla Enterprises, Helena, MT 59601
Sara E. Meloy, Montana Department of Natural Resources and Conservation, Helena, MT 59601
Ann C. Schwend, Montana Department of Natural Resources and Conservation, Helena, MT 59601
The Montana University System Water Center is part of a nationwide network of university-based Water Resources Research Institutes and is housed at Montana State University (www.montanawatercenter.org). The primary goals of the Water Center are to support water research and education, and to provide accurate and unbiased information on Montana’s most critical water issues. The Montana Water Center also serves as a connection point between the Montana University System and other water-focused entities and stakeholders in the stat
Published November 2020
Please cite this publication as: Lonsdale, W. R., Cross, W. F., Dalby, C. E., Meloy, S. E., Schwend, A. C., 2020. Evaluating Irrigation Efficiency: Toward a Sustainable Water Future for Montana, Montana University System Water Center, Montana State University, 42p., doi.org/10.15788/mwc202011
Table of CONTENTS
WATER AND IRRIGATED AGRICULTURE
Building a collective understanding
Figure 1| The multidisciplinary nature of irrigated agriculture
Box 1 | Defining irrigation efficiency
IRRIGATED AGRICULTURE IN MONTANA
Irrigation and crop type
Irrigation methods and changes over time
Motivating factors for converting to sprinkler irrigation
Motivating factors for maintaining flood irrigation
Figure 2 | Statewide irrigation consumption by 8-digit hydrological unit
Figure 3 | Conversion to sprinkler irrigation in Montana
Figure 4 | Conversions from flood to sprinkler irrigation near Hamilton and Bozeman, Montana.
Table 1 | Top crops in Montana
Box 2 | Irrigation methods
THE PARADOX OF IRRIGATION EFFICIENCY
Table 2 | Potential outcomes of different irrigation and conveyance methods
HYDROLOGY OF IRRIGATED AGRICULTURE
Figure 5 | Pathways of water flow in irrigated agriculture
Box 3 | Irrigation hydrology
ASSESSING CONSEQUENCES OF CHANGING IRRIGATION METHODS
The importance of spatial scale
Irrigation influences the spatial and temporal availability of water
Site specificity
Figure 6 | Spatial scale influences calculations of irrigation efficiency
Figure 7 | Importance of flow regime to aquatic ecology
Figure 8 | Conceptual differences in flow regime as a result of irrigation management practices
Table 3 | Terminology
Box 4 | Streamflow and aquatic ecosystems
WATER POLICY AND IRRIGATED AGRICULTURE
Montana water policy basics
Water policy and changes in irrigation method
Case Study 1: U.S. Supreme Court decision for the Tongue River Basin (Montana v. Wyoming)
Montana’s changing climate
Goal 1: Watershed-scale Irrigation Management and Water Budgeting
Goal 2: Supporting Aquifer Recharge
Case Study 2: Aquifer recharge through the use of irrigation canals in the Beaverhead (MT) and Teton (ID) watersheds
Case Study 3: Gold Creek: Maintenance of diverse irrigation methods to optimize water supply in Gold Creek, MT
Goal 3: Water Conservation
Table 4 | Knowledge gaps
Box 5 | Montana’s changing climate
Banner photo by Wyatt Cross
Table of Contents | Key Messages | Water and Irrigated Agriculture | Irrigated Agriculture in Montana | The Paradox of Irrigation Efficiency | Hydrology of Irrigated Agriculture | Assessing Consequences of Changing Irrigation Methods | Water Policy and Irrigated Agriculture | Adapting to Change | Conclusion | List of Contributors | Glossary | Footnotes | References