LANDSLIDE HAZARD INVESTIGATIONS FOLLOWING THE 1999 DISASTER IN COLORADO SPRINGS, COLORADO

Private and public properties in the City of Colorado Springs sustained significant damage during three weeks of nearly continuous rainfall in the spring of 1999. A Presidential Disaster Declaration was issued that covered both flooding and landsliding. As part of the Federal response, the Federal Emergency Management Agency (FEMA) provided the City over $4.5 million in funds under the Unmet Needs Program to acquire landslide-affected properties.

The acquisition program involved two main elements. First, homeowners signed up for consideration on a voluntary basis. Second, the property had to have incurred damage from landsliding as a result of the 1999 storm event. Because so many homeowners applied, the assessment of actual landslide damage became a key factor in prioritizing which properties would be purchased.

The Colorado Geological Survey (CGS) mapped and assessed landslide hazards at eleven locations throughout the city as part of the Unmet Needs Program. The mapping involved site reconnaissance, delineating the boundaries of the active landslides, and assessing the damage and threat to residential structures. A five-category, landslide hazard-rating system was devised based on position of residences relative to the active landslide boundaries. Over 150 individual properties were mapped and rated during the investigation.

The results of the investigation were submitted to FEMA and the Colorado Springs Office of Emergency Management, and could be purchased by the general public. To date, twenty-five properties have been acquired in six different locations throughout the City, and an additional two properties are pending acquisition by the fall of 2002. The homes are either demolished or moved and permanent deed restrictions, which create perpetual open space, are placed on each property.

As a follow-up project to aid in ongoing planning and mitigation efforts, FEMA and the City have contracted CGS to produce a GIS map of landslides and landslide-susceptible areas.