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Changes in the hydrologic regime of the Battle River basin, Alberta, Canada

1984; Elsevier BV; Volume: 71; Issue: 3-4 Linguagem: Inglês

10.1016/0022-1694(84)90102-1

1879-2707

W. J. Stolte, Ross Herrington,

Archaeology and Natural History

Abstract Flow records for the Battle River, Alberta, include those taken near Ponoka for a period in the early part of the century and those taken at the same location in the near past. Some questions have arisen as to whether these two sets of records can properly be combined for purposes of water-resource development. An investigation was made into whether a significant decrease in flows had occurred and if so, what caused the change. The reductions in the mean monthly flows were analyzed statistically and changes identified. Possible causes of these changes were investigated. They included variations in the precipitation regime, changes in the evapotranspiration regime and shifts in land-use and agricultural practices. Monthly flows of the Battle River near Ponoka from 1967 to 1979 were found to be significantly reduced from the level that prevailed from 1914 to 1932, except for spring flows. Spring flows remained virtually unchanged thereby indicating that the snow accumulation and snowmelt processes had not changed with time. It was concluded that the reductions in summer and winter flows indicated that the quickflow response of the basin to summer storms and also the delayed flow from soil-moisture drainage had decreased. Analysis of daily and monthly precipitation characteristics showed that changes in precipitation characteristics could not be considered responsible for most of the runoff changes. An increase in growing-season temperatures resulting in increased evapotranspiration is a possible partial cause of the decreased flows. Greatly increased use of fertilizer since 1950 has caused a substantial increase in crop yields. It was concluded that in all likelihood this increase has created a major increase in water use leading to a drop in soil-moisture content and then reductions in streamflow. Winter recharge of soil moisture from depth as reported in the literature was concluded to be the probable reason for little change in snowmelt runoff. A lack of change and even increases in runoff production in the lower Battle River basin were concluded to be due to generally lower moisture surpluses in the region, thus there was less sensitivity to fertilizer application rates, and also much lower rates of fertilizer application.