Coconino County IEACiviltec worked with the Coconino County Flood Control District and Department of Public Works to develop a data-driven process (IEA Guidelines) for the prioritization of flood control capital improvement projects. The IEAs are tools that provide relevant information to be considered by County staff and officials to make informed decisions regarding capital improvement project planning and programming.

The IEA goals include:

  • Hydrologic and hydraulic analysis of the study area
  • Assessment of the flood hazard
  • Determination of regulatory changes in the study area, if needed
  • Development of conceptual alternatives and selection of a recommended alternative to mitigate the flood hazard
  • Quantifiable prioritization of the study area for comparison against other study areas

Civiltec completed the guideline concurrently with the development of the Fort Valley IEA as a pilot project. The contributing drainage basin is approximately 29.3 square miles. FLO-2D (2-dimensional) modeling was used to estimate peak flow rates for various storm events, map the limits of inundation, and assess the flood hazard. Various alternatives such as on forest detention, property acquisition, an early warning system and neighborhood improvements were considered and scored based on a standardized set of criteria and a scoring matrix, which were developed through the IEA Guideline development process. Neighborhood improvements included storm drain, open channels, and detention as the highest scoring and recommended alternative.

The IEA process will be used to evaluate other floodplain and drainage problem areas. Scores from other geographic study areas will be compared against each other to assist in determining the most effective way to plan flood control capital improvement projects and budgets.

Key Issues & Solutions:
The development of a new standardized process for the County required input from several staff members and elected officials. Civiltec held bi-weekly meetings to keep all stakeholders well informed. We routinely provided draft copies of the IEA Guidelines and Fort Valley IEA for input. Based on input, we continually revised the process and guidelines to ensure all stakeholders were satisfied and completely vested in the outcome of the project.

Civiltec has previously worked with Coconino County on flood mitigation projects. Click here to read those project stories.