Saturday, August 18, 2007

Sculptors of the Land

The landscape of our Continent is a product of geology, tectonic forces and the erosive power of wind, water and ice. Though glacial topography abounds in Canada, New England, the Upper Midwest and the high western mountains, rivers and streams are the primary sculptors today. If you want to understand the topography of an area, look at a map of its streams.

Once again, our brief life span leads us to underestimate the power of flowing water. Only the occasional flash flood opens our eyes to the force that, over millions of years, molded the surface of North America. While landscapes such as the Grand Canyon and Columbia River Gorge are usually offered as examples, one might also consider the Western High Plains. Though now semiarid and home to few permanent streams, this Province is covered by a thick veneer of Rocky Mountain debris, spread across the region by large, meandering rivers over the past 65 million years.

Our efforts to harness rivers for power, flood control, irrigation and recreation, while well intentioned and beneficial, are doomed in the long run. Sediments will clog the reservoirs, the dams will eventually fail and the rivers will regain control of the land.