Man Made Failures: Preparation and Maintenance
The more recent dramatic incidents are good studies in over development, poor understanding of water as it flows through the earth and failures to spend the appropriate resources on maintenance and upkeep. These failures underscore the lack of proper education into the nature of water based erosion.
What's the big deal about water based erosion?
Water is crafty, sneaky and never sleeps. A small drip changes to a torrent in the blink of an eye. A good example can be seen in the 2008 hillside collapse on a south west Portland, Oregon hillside.
Early in October of 2008, the collapse of a hillside led to the condemning of six houses and the destruction of a neighbourhood. The event happened so quickly that the first house to fall came completely off of its foundation and started sliding down the hill into the next house. Not unlike a set of dominoes, they all fell down.
Comments from residents at the bottom of the hill seem to indicate that there was water running down their driveways the day before. While not uncommon in Portland, it was a clear day. This should have raised one or two flags in the minds of the residents of this area. Awareness is key as the effects of water based erosion can be slow or hidden from view.
In the end analysis, the slide appears to have been caused by high rain, steep slopes and a new sprinkler system that may have been improperly installed or damaged. The indicators were present though, higher water consumption and running water should have been noted by the home owners in the neighbourhood.