TENNESSEE ROCKFALL HAZARD MANAGMENT SYSTEM

Rockfall hazard management has historically been reactive rather than proactive. However, many states are now moving rapidly towards a more proactive approach, using field rating systems often based on the Rockfall Hazard Rating System (RHRS) developed by the National Highway Institute. This RHRS enables identification and prioritization of rockcuts for remediation and / or monitoring. In October 2000, the Tennessee DOT began a project to develop a Rockfall Management System (RMS) for these purposes and to fulfill the needs of the department. A revised RHRS was developed for Tennessee (TRHRS) that included more explicit descriptions of the geologic modes likely to contribute rockfall, field-based assessment of prior rockfall frequency, and improved assessment of ditch effectiveness. Phase I of the project developed the prototype TRHRS with initial testing in 5 counties with varied geology. Concurrently, field data gathering techniques and management tools were developed. Field data collection evolved from a paper form to digital via input into Personal Digital Assistant's (PDA's). Phase II, beginning October 2002, involved limited revision of the TRHRS, included collection of TRHRS data in the remaining seventy-three counties with rockfall potential in Tennessee and the implementation of a centralized database and GIS at TDOT. The data are available at TDOT through this database in a web-based GIS and as a data layer for analysis in a full-scale GIS program. The web-based GIS enables easy display, analysis and prioritization of rockfall hazards, which is a key component of the RMS. The RMS has already expanded to include landslide data, and we anticipate that the system will grow incorporate data about other geologic hazards that affect TDOT road construction and maintenance.