Identification of Critical Regions for Water Quality Monitoring with Respect to Seasonal and Annual Water Surplus

Transcription

1 Identification of Critical Regions for Water Quality Monitoring with Respect to Seasonal and Annual Water Surplus D.J. Fallow, D.M. Brown, G.W. Parkin, J.D. Lauzon and C. Wagner-Riddle. Department of Land Resource Science, University of Guelph Guelph, Ontario. N1G 2W1 May, 23 Land Resource Science Technical Memo No. 23-1

2 Copies of this publication are available for $15. per hard copy, or $5. per CD copy from: Department of Land Resource Science, OAC University of o f Guelph Guelph, Ontario N1G 2W1 Published by the Cartographic Section Department of Land Resource Science, OAC University of Guelph Guelph, Ontario N1G 2W1 LRS Contribution No Cover Credits: The water balance diagram was provided by David A. Rouleau, Cartographer, Resources and Planning Branch, OMAF. The two cover agriculture photographs were provided by Dr. R.L. Thomas, Department of Land Resource Science, University of Guelph. The image of the flooding caused Hurricane Hazel supplied by Dr H. Whiteley, School of Engineering, University of Guelph. ii

3 Table of Contents Introduction 1 Description and General Inputs for the SHAW Model 2 Shaw Model Site Characteristic Inputs Soil Temperature Inputs Volumetric Soil Water Content Inputs Climate Inputs Crop Inputs Site Specific Inputs 5 Site Specific Soil Inputs Soil Characteristics of an Embro Silt Loam. 9 Site Specific Climate Inputs Site Specific Crop Inputs. 1 Data Output and Presentation 14 SHAW Water Balance File SHAW Water Content File Data Presentation Results and Discussion 15 Annual Water Balance Comparisons of Annual Water Balance for Two Different Soil Types Monthly Values of Water Balance Components Comparison of the Year to Year Water Balance Components Between Two Soil Types Comparison of the Differences in Water Balance Components Between The Two Soils For Individual Years at Harrow ) Two years with similar total precipitation but contrasting monthly precipitation and water balance components ) Comparison of the water balance components for the two soils with considerable differences in total annual precipitation Variability in Water Surplus Seasonal Water Surplus Summary and Conclusions 53 References 55 Appendices Appendix A Appendix B Appendix C Appendix D Appendix E iii

4 List of Tables Table 1 Location and Ontario climate region of the study sites 5 Table 2 Horizon depths, hydraulic properties and percentage of each texture class for each horizon of the predominant soil type in the area of the seven study sites, a) through g). a) Emo b) Guelph c) Harrow d) Kapuskasing e) Mount Forest f) Ottawa g) Smithfield Table 3 Soil series, profile and soil hydraulic properties for an Embro Silt Loam Table 4 The average dates of occurrence of key stages in growth of corn at each of the study locations Table 5 Maximum values of crop height, leaf width, leaf area index, root depth and average accumulated crop heat units(aachu) used as SHAW model inputs for each study site Table 6 Maximum dry biomass used for year 2 and the intercept value for the linear relationship shown from 1954 to 21 in Figure 1 for the seven study sites used inputs for the SHAW model Table 7 Average and standard deviation (in brackets) of annual water balance components derived from the SHAW model for a typical soil profile at seven sites in Ontario Table 8 Average and standard deviation (in brackets) of annual water balance components derived from the SHAW model for an Embro soil profile soil profile at seven sites in Ontario.. 26 Table 9 Number of years that measured precipitation and SHAW model estimated deep drainage and runoff, exceeded the specified limits at the seven Ontario sites with typical and Embro soil types for 1954 to 21 period Table 1 Average seasonal totals for measured precipitation, simulated evapo-transpiration, deep drainage and runoff for the typical soil type at all sites for the 48-year study period. 51 Table 11 Average seasonal totals for measured precipitation, simulated evapo-transpiration, deep drainage and runoff for the Embro soil profile soil type at all sites for the 48-year study period Appendix A Table A-1 Location where climate elements were recorded at each of the primary climate sites. 59 Table A-2 Summary corn growth cycle inputs for the SHAW model for Emo Table A-3 Summary corn growth cycle inputs for the SHAW model for Guelph.. 63 Table A-4 Summary corn growth cycle inputs for the SHAW model for Harrow Table A-5 Summary corn growth cycle inputs for the SHAW model for Kapuskasing Table A-6 Summary corn growth cycle inputs for the SHAW model for Mount Forest iv

5 Table A-7 Table A-8 Summary corn growth cycle inputs for the SHAW model for Ottawa Summary corn growth cycle inputs for the SHAW model for Smithfield Table B-1 Table B-2 Table B-3 Table B-4 Table B-5 Table B-6 Table B-7 Appendix B Summary of estimated annual totals of water balance components using the SHAW model for Emo Summary of estimated annual totals of water balance components using the SHAW model for Guelph.. 71 Summary of estimated annual totals of water balance components using the SHAW model for Harrow Summary of estimated annual totals of water balance components using the SHAW model for Kapusasking Summary of estimated annual totals of water balance components using the SHAW model for Mount Forest Summary of estimated annual totals of water balance components using the SHAW model for Ottawa Summary of estimated annual totals of water balance components using the SHAW model for Smithfield Table C-1 Table C-2 Appendix C Summary of monthly averages of precipitation, and SHAW estimated evapo-transpiration, deep drainage and runoff for Emo. a) Emo monthly precipitation. 78 b) Emo monthly estimated evapo-transpiration c) Emo monthly estimated deep drainage d) Emo monthly estimated runoff e) Emo monthly estimated evapo-transpiration with an Embro soil profile 79 f) Emo monthly estimated deep drainage with an Embro soil profile. 79 g) Emo monthly estimated runoff with an Embro soil profile 79 Summary of monthly averages of precipitation, and SHAW estimated evapo-transpiration, deep drainage and runoff for Guelph. a) Guelph monthly precipitation. 8 b) Guelph monthly estimated evapo-transpiration... 8 c) Guelph monthly estimated deep drainage... 8 d) Guelph monthly estimated runoff... 8 e) Guelph monthly estimated evapo-transpiration with an Embro soil profile. 81 f) Guelph monthly estimated deep drainage with an Embro soil profile.. 81 g) Guelph monthly estimated runoff with an Embro soil profile.. 81 v

6 Table C-3 Table C-4 Table C-5 Table C-6 Summary of monthly averages of precipitation, and SHAW estimated evapo-transpiration, deep drainage and runoff for Harrow. a) Harrow monthly precipitation b) Harrow monthly estimated evapo-transpiration c) Harrow monthly estimated deep drainage d) Harrow monthly estimated runoff e) Harrow monthly estimated evapo-transpiration with an Embro soil profile 83 f) Harrow monthly estimated deep drainage with an Embro soil profile. 83 g) Harrow monthly estimated runoff with an Embro soil profile. 83 Summary of monthly averages of precipitation, and SHAW estimated evapo-transpiration, deep drainage and runoff for Kapuskasing. a) Kapuskasing monthly precipitation 84 b) Kapuskasing monthly estimated evapo-transpiration c) Kapuskasing monthly estimated deep drainage d) Kapuskasing monthly estimated runoff e) Kapuskasing monthly estimated evapo-transpiration with an Embro soil profile f) Kapuskasing monthly estimated deep drainage with an Embro soil profile g) Kapuskasing monthly estimated runoff with an Embro soil profile. 85 Summary of monthly averages of precipitation, and SHAW estimated evapo-transpiration, deep drainage and runoff for Mount Forest. a) Mount Forest monthly precipitation b) Mount Forest monthly estimated evapo-transpiration.. 86 c) Mount Forest monthly estimated deep drainage.. 86 d) Mount Forest monthly estimated runoff.. 86 e) Mount Forest monthly estimated evapo-transpiration with an Embro soil profile.. 87 f) Mount Forest monthly estimated deep drainage with an Embro soil profile g) Mount Forest monthly estimated runoff with an Embro soil profile Summary of monthly averages of precipitation, and SHAW estimated evapo-transpiration, deep drainage and runoff for Ottawa. a) Ottawa monthly precipitation b) Ottawa monthly estimated evapo-transpiration c) Ottawa monthly estimated deep drainage d) Ottawa monthly estimated runoff e) Ottawa monthly estimated evapo-transpiration with an Embro soil 89 profile f) Ottawa monthly estimated deep drainage with an Embro soil profile.. 89 g) Ottawa monthly estimated runoff with an Embro soil profile. 89 vi

7 Table C-7 Summary of monthly averages of precipitation, and SHAW estimated evapo-transpiration, deep drainage and runoff for Smithfield. a) Smithfield monthly precipitation 9 b) Smithfield monthly estimated evapo-transpiration... 9 c) Smithfield monthly estimated deep drainage.. 9 d) Smithfield monthly estimated runoff.. 9 e) Smithfield monthly estimated evapo-transpiration with an Embro soil profile f) Smithfield monthly estimated deep drainage with an Embro soil profile 91 g) Smithfield monthly estimated runoff with an Embro soil profile. 91 Table D-1 Table D-2 Table D-3 Table D-4 Table D-5 Table D-6 Table D-7 Appendix x D Summary of estimated annual totals of water balance components using the SHAW model for Emo for an Embro soil profile.. 1 Summary of estimated annual totals of water balance components using the SHAW model for Guelph for an Embro soil profile.. 11 Summary of estimated annual totals of water balance components using the SHAW model for Harrow for an Embro soil profile.. 12 Summary of estimated annual totals of water balance components using the SHAW model for Kapuskasing for an Embro soil profile.. 13 Summary of estimated annual totals of water balance components using the SHAW model for Mount Forest for an Embro soil profile Summary of estimated annual totals of water balance components using the SHAW model for Ottawa for an Embro soil profile.. 15 Summary of estimated annual totals of water balance components using the SHAW model for Smithfield for an Embro soil profile.. 16 Appendix E Table E-1a Summary of estimated water balance components for the winter months (December, January, February and March) using the SHAW model for Emo.. 11 Table E-1b Summary of estimated water balance components for the spring months (April and May) using the SHAW model for Emo Table E-1c Summary of estimated water balance components for the summer months (June, July and August) using the SHAW model for Emo Table E-1d Summary of estimated water balance components for the fall months (September, October and November) using the SHAW model for Emo vii

8 Table E-2a Summary of estimated water balance components for the winter months (December, January, February and March) using the SHAW model for Guelph Table E-2b Summary of estimated water balance components for the spring months (April and May) using the SHAW model for Guelph Table E-2c Summary of estimated water balance components for the summer months (June, July and August) using the SHAW model for Guelph Table E-2d Summary of estimated water balance components for the fall months (September, October and November) using the SHAW model for Guelph Table E-3a Summary of estimated water balance components for the winter months (December, January, February and March) using the SHAW model for Harrow Table E-3b Summary of estimated water balance components for the spring months (April and May) using the SHAW model for Harrow Table E-3c Summary of estimated water balance components for the summer months (June, July and August) using the SHAW model for Harrow Table E-3d Summary of estimated water balance components for the fall months (September, October and November) using the SHAW model for Harrow Table E-4a Summary of estimated water balance components for the winter months (December, January, February and March) using the SHAW model for Kapuskasing Table E-4b Summary of estimated water balance components for the spring months (April and May) using the SHAW model for Kapuskasing Table E-4c Summary of estimated water balance components for the summer months (June, July and August) using the SHAW model for Kapuskasing kasing Table E-4d Summary of estimated water balance components for the fall months (September, October and November) using the SHAW model for Kapuskasing Table E-5a Summary of estimated water balance components for the winter months (December, January, February and March) using the SHAW model for Mount Forest Table E-5b Summary of estimated water balance components for the spring months (April and May) using the SHAW model for Mount Forest Table E-5c Summary of estimated water balance components for the summer months (June, July and August) using the SHAW model for Mount Forest Table E-5d Summary of estimated water balance components for the fall months (September, October and November) using the SHAW model for Mount Forest viii

9 Table E-6a Summary of estimated water balance components for the winter months (December, January, February and March) using the SHAW model for Ottawa Table E-6b Summary of estimated water balance components for the spring months (April and May) using the SHAW model for Ottawa Table E-6c Summary of estimated water balance components for the summer months (June, July and August) using the SHAW model for Ottawa Table E-6d Summary of estimated water balance components for the fall months (September, October and November) using the SHAW model for Ottawa Table E-7a Summary of estimated water balance components for the winter months (December, January, February and March) using the SHAW model for Smithfield Table E-7b Summary of estimated water balance components for the spring months (April and May) using the SHAW model for Smithfield Table E-7c Summary of estimated water balance components for the summer months (June, July and August) using the SHAW model for Smithfield Table E-7d Summary of estimated water balance components for the fall months (September, October and November) using the SHAW model for Smithfield ix

10 List of Figures Figure 1 Yearly Corn Dry Biomass Values in Ontario from 198 to 2 (OMAF, 21).. 13 Figure 2 Averages of annual precipitation and annual water balance components derived from the SHAW model for a typical soil profile at seven sites in Ontario Figure 3 Percentage of the total annual precipitation of SHAW model values for evapotranspiration, run off and deep drainage for a typical soil profile at seven sites in Ontario. The actual model estimated values of water (in mm) appear in each bar with the total average annual precipitation (in mm) are provided in brackets below the site name. 18 Figure 4 Annual measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the 1954 to 21 period using the typical soil type at Emo. The arrow on the y-axis indicates the mean annual precipitation for the site Figure 5 Annual measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the 1954 to 21 period using the typical soil type at Guelph. The arrow on the y-axis indicates the mean annual precipitation for the site Figure 6 Annual measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the 1954 to 21 period using the typical soil type at Harrow. The arrow on the y-axis indicates the mean annual precipitation for the site Figure 7 Annual measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the 1954 to 21 period using the typical soil type at Kapuskasing. The arrow on the y-axis indicates the mean annual precipitation for the site Figure 8 Annual measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the 1954 to 21 period using the typical soil type at Mount Forest. The arrow on the y-axis indicates the mean annual precipitation for the site Figure 9 Annual measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the 1954 to 21 period using the typical soil type at Ottawa. The arrow on the y-axis indicates the mean annual precipitation for the site Figure 1 Annual measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the 1954 to 21 period using the typical soil type at Smithfield ithfield. The arrow on the y-axis indicates the mean annual precipitation for the site Figure 11 Averages of annual precipitation and annual water balance components derived from the SHAW model for an Embro soil profile soil profile at seven sites in Ontario Figure 12 Percentage of the total annual precipitation of SHAW model values for the evapotranspiration, run off and deep drainage for an Embro soil profile at seven sites in Ontario. The actual model estimated values of water (in mm) appear in each bar with the total average annual precipitation (in mm) are found in brackets below the site name x

11 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 18 Figure 19 Figure 2 Figure 21 Figure 22 Figure 23 Figure 24 Figure 25 Comparison of the monthly evapo-transpiration (a), deep drainage (b) and runoff (c) for the typical soil and the Embro soil profile at Emo. The yearly averages are given in brackets beside soil type in the legend Comparison of the monthly evapo-transpiration (a), deep drainage (b) and runoff (c) for the typical soil and the Embro soil profile at Guelph. The yearly averages are given in brackets beside soil type in the legend Comparison of the monthly evapo-transpiration (a), deep drainage (b) and runoff (c) for the typical soil and the Embro soil profile at Harrow. The yearly averages are given in brackets beside soil type in the legend Comparison of the monthly evapo-transpiration (a), deep drainage (b) and runoff (c) for the typical soil and the Embro soil profile at Kapuskasing. The yearly averages are given in brackets beside soil type in the legend Comparison of the monthly evapo-transpiration (a), deep drainage (b) and runoff (c) for the typical soil and the Embro soil profile at Mount Forest. The yearly averages are given in brackets beside soil type in the legend Comparison of the monthly evapo-transpiration (a), deep drainage (b) and runoff (c) for the typical soil and the Embro soil profile at Ottawa. The yearly averages are given in brackets beside soil type in the legend Comparison of the monthly evapo-transpiration (a), deep drainage (b) and runoff (c) for the typical soil and the Embro soil profile at Smithfield. The yearly averages are given in brackets beside soil type in the legend Effective profile saturated hydraulic conductivities for the seven typical soils and the Embro soil profile (a) Monthly recorded precipitation for 1968 and 199, and SHAW model estimated evapo-transpiration for the typical soil (Brookston clay loam) and an Embro soil profile for 1968 (b) and 199 (c) at Harrow. The yearly values are given in brackets beside soil type in the legend (a) Monthly recorded precipitation for 1968 and 199, and SHAW model estimated deep drainage for the typical soil (Brookston clay loam) and an Embro soil profile for 1968 (b) and 199 (c) at Harrow. The yearly values are given in brackets beside soil type in the legend. 42 (a) Monthly recorded precipitation for 1968 and 199, and SHAW model estimated runoff for the typical soil (Brookston clay loam) and an Embro soil profile for 1968 (b) and 199 (c) at Harrow. The yearly values are given in brackets beside soil type in the legend.. 43 (a) Monthly recorded precipitation for 1969 and 1991, and SHAW model estimated evapo-transpiration for the typical soil (Brookston clay loam) and an Embro soil profile for 1969 (b) and 1991 (c) at Harrow. The yearly values are given in brackets beside soil type in the legend (a) Monthly recorded precipitation for 1969 and 1991, and SHAW model estimated deep drainage for the typical soil (Brookston clay loam) and an Embro soil profile for 1969 (b) and 1991 (c) at Harrow. The yearly values are given in brackets beside soil type in the legend. 46 xi

12 Figure 26 (a) Monthly recorded precipitation for 1969 and 1991, and SHAW model estimated runoff for the typical soil (Brookston clay loam) and an Embro soil profile for 1969 (b) and 1991 (c) at Harrow. The yearly values are given in brackets beside soil type in the legend.. 47 Appendix D Figure D-1 Differences in annual simulated evapo-transpiration, deep drainage and runoff for the 1954 to 21 period for an Embro soil profile as compared to the typical soil type at Emo.. 93 Figure D-2 Differences in annual simulated evapo-transpiration, deep drainage and runoff for the 1954 to 21 period for an Embro soil profile as compared to the typical soil type at Guelph.. 94 Figure D-3 Differences in annual simulated evapo-transpiration, deep drainage and runoff for the 1954 to 21 period for an Embro soil profile as compared to the typical soil type at Harrow.. 95 Figure D-4 Differences in annual simulated evapo-transpiration, deep drainage and runoff for the 1954 to 21 period for an Embro soil profile as compared to the typical soil type at Kapuskasing.. 96 Figure D-5 Differences in annual simulated evapo-transpiration, deep drainage and runoff for the 1954 to 21 period for an Embro soil profile as compared to the typical soil type at Mount Forest Figure D-6 Differences in annual simulated evapo-transpiration, deep drainage and runoff for the 1954 to 21 period for an Embro soil profile as compared to the typical soil type at Ottawa Figure D-7 Differences in annual simulated evapo-transpiration, deep drainage and runoff for the 1954 to 21 period for an Embro soil profile as compared to the typical soil type at Smithfield Appendix E Figure E-1a Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the winter months (December, January, February and March) during 1954 to 21 using the typical soil type at Emo Figure E-1b Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the spring months (April and May) during 1954 to 21 using the typical soil type at Emo Figure E-1c Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the summer months (June, July and August) during 1954 to 21 using the typical soil type at Emo xii

13 Figure E-1d Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the fall months (September, October and November) during 1954 to 21 using the typical soil type at Emo Figure E-2a Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the winter months (December, January, February and March) during 1954 to 21 using the typical soil type at Guelph Figure E-2b Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the spring months (April and May) during 1954 to 21 using the typical soil type at Guelph Figure E-2c Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the summer months (June, July and August) during 1954 to 21 using the typical soil type at Guelph Figure E-2d Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the fall months (September, October and November) during 1954 to 21 using the typical soil type at Guelph Figure E-3a Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the winter months (December, January, February and March) during 1954 to 21 using the typical soil type at Harrow Figure E-3b Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the spring months (April and May) during 1954 to 21 using the typical soil type at Harrow.. 12 Figure E-3c Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the summer months (June, July and August) during 1954 to 21 using the typical soil type at Harrow Figure E-3d Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the fall months (September, October and November) during 1954 to 21 using the typical soil type at Harrow Figure E-4a Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the winter months (December, January, February and March) during 1954 to 21 using the typical soil type at Kapuskasing Figure E-4b Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the spring months (April and May) during 1954 to 21 using the typical soil type at Kapuskasing Figure E-4c Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the summer months (June, July and August) during 1954 to 21 using the typical soil type at Kapuskasing Figure E-4d Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the fall months (September, October and November) during 1954 to 21 using the typical soil type at Kapuskasing xiii

14 Figure E-5a Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the winter months (December, January, February and March) during 1954 to 21 using the typical soil type at Mount Forest Figure E-5b Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the spring months (April and May) during 1954 to 21 using the typical soil type at Mount Forest Figure E-5c Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the summer months (June, July and August) during 1954 to 21 using the typical soil type at Mount Forest Figure E-5d Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the fall months (September, October and November) during 1954 to 21 using the typical soil type at Mount Forest Figure E-6a Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the winter months (December, January, February and March) during 1954 to 21 using the typical soil type at Ottawa Figure E-6b Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the spring months (April and May) during 1954 to 21 using the typical soil type at Ottawa Figure E-6c Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the summer months (June, July and August) during 1954 to 21 using the typical soil type at Ottawa Figure E-6d Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the fall months (September, October and November) during 1954 to 21 using the typical soil type at Ottawa Figure E-7a Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the winter months (December, January, February and March) during 1954 to 21 using the typical soil type at Smithfield Figure E-7b Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the spring months (April and May) during 1954 to 21 using the typical soil type at Smithfield Figure E-7c Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the summer months (June, July and August) during 1954 to 21 using the typical soil type at Smithfield Figure E-7d Measured precipitation and simulated evapo-transpiration, deep drainage and runoff for the fall months (September, October and November) during 1954 to 21 using the typical soil type at Smithfield thfield xiv

15 Acknowledgments Financial support provided by the Innovation and Risk Management Branch, Ontario Ministry of Agriculture and Food and Pioneer Hi-Bred Limited was greatly appreciated. Our gratitude is extended to Sarah Kennedy, Elanor Waslander and Joanna Passmore for their carefulness in assisting in updating the climate data for the four previous sites and in preparing climate data for the three additional sites. The authors also thank Bryan Smith at Environment Canada for his assistance in collecting the climate data for this project; Kim Jo Bliss Calder of the Emo Agriculture Research Station for allowing us to collect samples from the soil profile and for providing insight to the Emo region; Reinder De Jong, Andrew Bootsma and Chin Tan of Agriculture and Agri-Food Canada for their valuable comments and information on the local sites where data were collected for this project. xv

16 Abstract The variability in seasonal and annual surplus water in seven regions of Ontario is estimated and analyzed in this publication. Surplus water is that water resulting from precipitation that runs off the land surface or drains through the soil profile eventually reaching the groundwater table. Surplus water as either runoff or deep drainage may carry pollutants that could lead to surface water or groundwater contamination. Knowledge of the timing, amount and form of surplus water in a given region of Ontario would assist in the prediction of when surface water and groundwater are more susceptible to contamination. For example, this information could potentially be used by farmers as related to nutrient management practices. A one-dimensional, deterministic model that simulated water flow in soil, including plant uptake, evapotranspiration, and freeze/thaw conditions was used to estimate the water surpluses. This model, referred to as the Simultaneous Heat and Water (SHAW) model, was applied to daily climate data from January 1, 1954 to December 31, 21 for recording sites in seven climate regions: Emo, Harrow, Guelph, Kapuskasing, Mount Forest, Ottawa and Smithfield. A corn crop and the typical soil profile conditions for each region, with the hydraulic properties for the typical soil were used as inputs for the model. To differentiate between the effects of soil type and climate on the components of the water balance, a second model run for all sites using an Embro silt loam profile was performed. The seasons were divided into winter (December, January, February and March); spring (April and May); summer (June, July and August); and fall (September, October and November). There were significant differences in average annual and seasonal water surpluses among the seven regions. The variability from year to year was significant. Most of the annual surplus water occurred in the winter and spring seasons, and in some years the surplus exceeded the precipitation in the spring season. The latter would be due to winter snow accumulations lasting into the spring season before melting. Deep drainage exceeded runoff at four of the seven sites for the typical soil profile in the region and at three of the sites for an Embro soil profile. Of the three sites where runoff exceeded deep drainage for the typical soil profile, the difference was most pronounced at Kapuskasing, because of the disproportionate snow melt in the spring season. Deep drainage was relatively small at Emo and Harrow, actually becoming negative on an annual basis for the Embro soil profile caused by greater upward water movement into the 1.25 m profile. Due to the adjustments to the lower boundary water content and soil temperature conditions in this work, soil type had an influence on the water balance that was not apparent in our previous work. The most critical regions for monitoring water surplus occur in the snow belt region east of Lake Huron and in areas where sandy soils predominate as shown for Smithfield. xvi

17 Introduction Spatial and temporal variations in precipitation and soil type can result in considerable differences in water surpluses. These variations lead to fluctuations in the amount of infiltrating water moving through the profile to depth resulting in groundwater recharge, as well as the quantity of water ending up as surface runoff. Both of these factors influence the transport of chemicals, and their concentration in surface waters and groundwater. Studies of the chemical pollution and biological contamination of groundwater, streams and lakes require analyses of the variability in water surpluses. Most studies that describe the climate of specific geographic regions include maps of the average water surplus, which are usually based on the water balance method developed by Thornthwaite (1948). Water surplus maps have been published for regions in Canada (Chapman and Brown, 1966; Sanderson and Phillips, 1967) and for Southern and Northern Ontario (Brown et al.,1968; Chapman and Thomas, 1968). A recent study by Fallow et al. (1999), used yearly climate data and the Simultaneous Heat and Water (SHAW) model (Flerchinger and Saxton, 1989a and b) to calculate the temporal variation in total flux of water through a specific depth for four specific sites in Ontario (Guelph, Harrow, Kapuskasing and Ottawa). Soil freezing and thawing plays an important role in determining the amount of water surplus in Ontario, prompting the selection of the SHAW model which contains algorithms describing these phenomena. Hayhoe (1994) found fairly good agreement between estimated and observed winter soil temperatures (at specific depths), liquid and total water contents for both snow-covered and snowcleared sites, as well as estimates of snow depth and timing and rate of snow melt. The objective of this study was to evaluate the temporal variability of water surpluses for seven different regions in Ontario, using the SHAW model to expand the work of Fallow et al. (1999). Three other locations including one in the Lake Huron snow belt, one along the north shore of Lake Ontario and a site in Northwestern Ontario were added to the four sites of the original work. In the original study, a single set of corn growth parameters was used for all thirty years and at all sites. In the current study, the corn growth parameters were determined yearly based on climate properties of each site. As well, the boundary input files were adjusted to contain more information from the region being studied. The daily climate data through the entire year for 48-years ( ) was used as input for these model runs expanding on the 3-year ( ) time period of the first study. 1

18 Description and General Inputs for the SHAW Model SHAW Model The Simultaneous Heat and Water model (SHAW model) is a one-dimensional model originally developed to mathematically simulate freezing and thawing in soils (Flerchinger and Saxton, 1988). In subsequent years, the SHAW model has evolved into a one-dimensional model capable of simulating water and heat flows through a profile that extends from the top of a plant canopy through a snow layer, plant residue layer and finally through soil layers to a user specified depth (Flerchinger and Saxton, 1989a and 1989b; Flerchinger et al. 1996; Flerchinger and Pierson, 1997). The software package identified by the authors of the SHAW model as SHAW2.5 was used in this simulation. Although the package was referred to as SHAW2.5, the model version included was SHAW2.3. The model requires input files for site characteristics, soil temperature, soil water, site climate and crop characteristics. Site Characteristic Inputs For each location analyzed, a file which contained general information about each site had to be created. Included in this file was information regarding the location of the site, soil properties and hydraulic parameters, crop information and the time and date information for the model run. For example, information regarding the start and end hours and dates for each particular run, elevation and latitude were provided in this file. Default plant parameter values supplied within the Site Characteristic File were used, while plant inputs specific to locations were included in the Crop Input File (discussed below). The SHAW model user defines the type and number of plant species present (including no vegetation) and the presence or absence of residue on the soil surface. The plant and residue characteristics are defined in terms of their ability to transport water and energy at different times throughout the year. The soil profile is defined through user-defined nodes; where the energy and water balance is determined. At each node, soil properties including soil pore index, air entry value, saturated hydraulic conductivity, bulk density, porosity, texture and organic matter are included in the site input file. The positioning of the nodes allow the user to define soil horizons and soil type in a one-dimensional profile. To facilitate a comparison of the water surplus from a climate and soil type perspective, the slope of the land was set to zero and the maximum amount of ponded water permitted on the soil surface for each site was fixed at 5 mm. Typical wet and dry soil albedos (.15 and.3, respectively) and water release curve properties were used to determine the SHAW model exponent parameter for calculating the albedo of moist soil. Soil Temperature Inputs The SHAW model requires an input file containing the initial and final day soil temperatures for each node. The initial soil temperatures throughout the profile are needed; however, only the lower boundary node soil temperatures on the final day are required. The initial soil temperature values were determined through a trial run of the SHAW model. The values of soil temperatures at the lower soil boundary were interpolated using the starting and final day for all other days of the simulation. Soil temperature profiles may also be added to the soil temperature input file throughout the entire time 2

19 duration of the simulation. These additional profiles were used to fix the bottom boundary soil temperature for specified days of the simulation, while values for the other nodes were for comparison purposes only and were not used in this study. Initially a SHAW model determined lower boundary temperature was used; however, it was found that in some years modeled soil profiles would not thaw completely in the spring leaving a small layer of ice at a nodal position somewhere in the profile. This would eventually disrupt the SHAW model causing the run to prematurely stop. Hence, the soil temperature at the bottom boundary (1.25 m depth) was input on a monthly basis for all sites for the entire 48-year period estimated from long-term monthly averages. The 3-year normal monthly soil temperatures available at depths ranging from.5 m to 3. m were available for Harrow, Kapuskasing and Ottawa. Average monthly soil temperatures at 1.25 m were estimated by averaging the temperatures at the 1. m and 1.5 m positions. Although the entire soil temperature profiles can be provided as inputs, the SHAW model only considers the bottom boundary (deepest nodal position) temperature. If the bottom boundary soil temperature node is provided for two non-consecutive days, the SHAW model assumes that the soil temperature at this node changes linearly between the two dates given. Variation on a monthly basis of the soil temperature at the lower boundary position (1.25 m) from the 3-year normal soil temperatures was created by comparing the previous month s average maximum air temperature to the 48-year normal maximum air temperature for the particular month. If it deviated from the normal maximum air temperature, then the mean lower boundary soil temperature for the subsequent month was adjusted in a manner that preserved both the mean and the standard deviation over the 48 year period. Soil temperature data from the 196 s and 197 s was also available for the Elora Research Station. As in the cases where the 3-year normals were available, the 1.25 m soil temperature was determined by averaging the soil temperatures immediately above and below this depth. These temperatures were then averaged to provide monthly normal temperatures at a 1.25 m depth for the Guelph and the Mount Forest locations. The soil temperature input file was then constructed in a similar manner as described for the previous sites. Smithfield values were based on the average of the Ottawa 3-year normals and Guelph values. The Emo site was estimated using the 3-year soil temperature normals from the Agriculture Canada Research Site at Morden, Manitoba since soil temperatures were not available for the Emo Research Station Site, and the two sites had similar monthly mean maximum and minimum air temperatures and precipitation. Volumetric Soil Water Content Inputs This file contains the soil water content by node for the initial and the final days of the simulation. The initial soil water contents are used directly by the model and only the deepest node in the soil profile for any additional input days, including the final day, are considered fixed during the simulation. The soil water input file was set at a fixed volumetric water content that corresponded to a soil water pressure head of 12 m for each site in the study by Fallow et al. (1999). This was determined by calibrating the SHAW model to a field based water balance for corn near Kintore, Ontario (Lat 43º 1 N, Long 81º 4 W and elevation approximately 34 m) (Rudolph et al., 1998). Sufficient weather and soils data were collected to permit the SHAW to be run for this location. The static bottom boundary soil 3

20 water content value was then adjusted until the model produced results equivalent to the measured data from the field. The corresponding soil water pressure head for the calibrated volumetric water content was then used to estimate the subsequent volumetric water contents for the study sites. Although the use of a fixed bottom boundary water content would provide model output that was reasonable over the duration of the run on average, a method of improving the bottom boundary volumetric water content estimates was attempted in this study in order to improve short term water surplus estimates. In this study an initial model run over the 48-year period was completed for each site using a fixed volumetric water content at the lower soil boundary node. Following this initial simulation, the daily water content at a nodal position within the same horizon as the lower boundary node was used to obtain a long-term volumetric water content average (comparable to the 3 year soil temperature normals in the soil temperature input file). These averages were used as a guide when taking into account monthly variability of the volumetric water content at the lower boundary position. The selected nodal position was chosen to be far enough away from the lower boundary nodal position as to be not greatly influenced by its constant volumetric water content. Therefore, it was assumed that most fluctuations in volumetric water content at this position were due to the events above this node or from the soil surface. In order to adjust the long term volumetric water content averages, the two previous months precipitation were summed and compared to the average precipitation for these months from the 48-year precipitation data. In a method similar to the soil temperature input file determination, if the sum for the actual months was different from the average months total, the volumetric water content at the lower boundary was adjusted accordingly. The modifications to the lower boundary volumetric water contents were made in such a manner as to maintain the mean and the variance of the original nodal position. A monthly soil water input file spanning the entire 48 year period was then generated using these values. Again, as in the soil temperature input file, the days in between the monthly inputs change linearly from one day to the next. The model was run again with the new soil water input file and the pattern of water content from the lower boundary position was compared to the pattern of the previously selected node within the same horizon. The soil water input file was then slightly modified until reasonable agreement between the two nodal patterns was attained. Climate Inputs The SHAW model also requires that the meteorological data for each site be included. For this study, the SHAW model was run on a daily time step. The input file for each of the seven sites included daily values for maximum temperature, minimum temperature, dew point temperature, wind run, precipitation and solar radiation. The climate input files were assembled to include daily values from January 1, 1954 to December 31, 21, for a total of 48 years for each site. Crop Inputs The model was run with a representative corn crop at each site for each year of the duration of the simulation. The SHAW model requires that the height, a characteristic dimension (leaf width), dry biomass, leaf area index and the rooting depth of each plant species be defined for various days throughout the year. If days were missing between entries, values were then assumed to change linearly between days. A simple secondary program was created to generate these numbers for daily intervals throughout the year for all 48 years. Further details are provided in Site Specific Crop Inputs sections. 4

21 Site Specific Inputs The Ontario sites selected for this study were: Emo, Guelph, Harrow, Kapuskasing, Mount Forest, Ottawa and Smithfield. The location of each site is provided in Table 1. Table 1: Location and Ontario climate region of the study sites. Site latitude (N) longitude (W) elevation (m.a.s.l.) climatic region* Emo 48º 38 93º m Rainey River Guelph 43º 3 8º m Huron Slopes Harrow 42º 5 82º m Leamington Kapuskasing 49º 25 82º m Northern Clay Belt Mount Forest 43º 58 8º m Dundalk Upland Ottawa 45º 2 75º 4 1 m Eastern Counties Smithfield 44º 5 77º m South Slopes * As defined in Climate of Southern and Northern Ontario, (Brown et al. (1968), and Chapman and Thomas, (1968)) Site Specific Soil Inputs A typical soil type was selected and characterized for each study site in Table 2. The soil profile for each site was divided into three main horizons: A, B and C. Depths to the bottom of each horizon were estimated based on Table 2 of Webber and Tel (1966), Selirio et al. (1978), and based on soil survey reports (Emo: Ontario Institute of Pedology and the Land Resource Research Institute (1984); Guelph: Hoffman et al. (1963); Harrow: Richards et al. (1989); Kapuskasing: Crane (1933); Mount Forest: Hoffman et al. (1963); Ottawa: Schut and Wilson (1987); Smithfield: Hoffman and Acton (1974)). The lowest depth considered in this application was 1.25 m. Soil hydraulic properties including the pore size distribution index (p.s.d.i.), air entry value, saturated hydraulic conductivity (Ksat), and bulk density (ρb) were also required at each node. For most sites the soil moisture release curves were approximated based on measurements reported by Crane (1933), Webber and Tel (1966) and Selirio et al. (1978), and by utilizing the soils data set included with the HYDRUS 2D (Simunek et al. 1996) software package. The SHAW model bases the moisture release curve on the equation developed by Brooks and Corey (1966), which requires two parameters. The pore size distribution index (p.s.d.i.) refers to the first of the two Brooks and Corey parameters, and the second parameter required by the SHAW model is the air entry soil water pressure head. Published moisture release data were limited to three soil water pressure heads: saturation ( bar), field capacity (-.33 bar) and the permanent wilting point (-15 bar). Due to the limited number of points for the typical soils at Guelph, Harrow and Ottawa, the air entry soil water pressure head was set to -.1 m and the pore size distribution index was determined by fitting the Brooks and Corey equation 5

22 to the data. Moisture release parameters were obtained for the other sites from the HYDRUS 2D package based on the textural data for the van Genuchten (198) moisture release function, and were converted to the equivalent Brooks and Corey parameters. The saturated hydraulic conductivity values (Ksat) were derived based on the typical soil type using Webber and Tel (1966) and the HYDRUS 2D soil texture and Ksat data set. The bulk density (ρb) at each node was calculated based on the saturated volumetric water content collected for the moisture release curve. The specific values for the soil layers of the typical soil profile at each site are provided in Table 2. Table 2: Horizon depths, hydraulic properties and percentage of each texture class for each horizon of the typical soil type in the area of the seven study sites, a) through g). Note: p.s.d.i. pore size distribution index Ksat saturated hydraulic conductivity bulk density ρb a) Emo: Emo Clay horizon horizon depth p.s.d.i. air entry K sat ρ b porosity sand silt clay (m) (m) (m s -1 ) (kg m -3 ) (%) (%) (%) A A B C C