HUMAN USE OF NATURAL RESOURCES IN THE SOUTH OKANAGAN AND LOWER SIMILKAMEEN VALLEYS

Richard J. Cannings and Eva Durance

HISTORICAL WATER USE

NINETEENTH CENTURY

In spite of the large lakes in the Okanagan Valley, water is likely the single most important factor limiting human activities, at least since the advent of large-scale agriculture in the area. The South Okanagan and Similkameen are no longer considered deserts in the technical sense of receiving less than 10 inches of precitipation yearly, but they are semi-arid below sub-alpine elevations. Annual mean values for recording stations in the south range from 249 mm at Keremeos to 315 mm at Kelowna. In the sub-alpine 600 mm and in the alpine about 700 mm of rain and snow fall yearly; thus the lower elevation lands depend on mountain snowpack draining through creek, river, and small upland lake systems for their yearly supply. As well, the storage capabilities of wetlands in the bottomlands were extremely important during hot, dry summers, although their use as storage areas has diminished seriously as their extent has decreased to approximately 15% of their original area.

Prior to European settlement of the study area, waterways, wetlands, and riparian vegetation occupied the greater part of the bottomlands. The main lakes have never been exceptionally biologically productive because of their configuration, (T. Northcote, presentation to City of Penticton Waterfront 2000 Committee, 1995) but large and small cattail and bulrush marshes along their shorelines provided important habitat for waterfowl, shorebirds, and other marsh-dwelling birds , muskrats, amphibian species, and fish. Extensive cottonwood stands and the aassociated thickets of osier dogwood, alder, water birch, and Nootka rose harboured many native bird, mammal, reptile, and amphibian species. Okanagan River meandered through much of its length through miles of oxbows and marshes into Osoyoos Lake and thence across the border to its junction with the mighty Columbia River. Ocean-run salmon spawned as far north as Penticton.

This whole water system was fed from tributary creeks originating high in the hills and mountains and fed mainly from the yearly snowpack and rain of the higher elevations. The undisturbed upland forests, bottomland wetlands and marshes and their shoreline vegetation controlled spring runoff to a large extent. In years of especially high precipitation, however, the lakes and River flooded, adding organic matter to the shores of the lakes and encouraging the growth of more riparian vegetation. The Okanagan people fished these lakes and rivers and built their winter villages from wood gathered along the banks, but the waterways remained in their natural state.

The early fur traders did not disturb the system either; however, the coming of large numbers of livestock to the Valley followed by the growth of horticultural agriculture signalled the beginning of significant changes in the use and configuration of waterways and their associated riparian vegetation.The dramatic changes in the waterway systems and destruction of wetlands in the subject area since the early 20th century have drastically diminished wildlife habitat and species dependent on the vegetation and conditions created by the natural yearly cycles of spring runoff and summer low, or no, water. This includes native fish and other aquatic life forms . As the economy of the area changed from ranching to horticultural agriciulture, forestry, and now increased urbanization and tourism, water-dependent wildlife habitat was destroyed and altered, often in irreversible ways.