| Abstract/Description or Keywords |
The first impressions of fans can be that they are excellent opportunities for logging, clearing for farms, building roads and locating communities. These gently sloping conical deposits of sediments form where streams lose confinement. They appear as an oasis of opportunity in mountainous and hilly terrain. Such is the case across British Columbia. However, experience has proven time and again that these landforms present a range of significant hazards. Periodic debris flows and floods spread sediments and water well beyond the unvegetated channel. Seemingly innocent excavations into the gravel channels quickly become deeply entrenched gorges. Streamside vegetation clearing leads to channel widening with de-watering of the shallow channel as summer progresses. Fans in British Columbia are very definitely a hazard for human developments, but we generally recognize this too late. As there are disturbed fans throughout B.C., it would also appear that we don’t seem to “learn our lessons”. |
