Flood Damage Reduction of Debris Flows for the City of Aguadilla Using Concrete Crib Dam and Channel Improvements

The Rio Ojo de Agua Flood Control Project was authorized to reduce flood damages to the historic municipal area of Aguadilla in Puerto Rico. Frequent storm events impacts the area with flooding and large sediment loads, which include large rocks and debris. The impacted area is highly urbanized with several significant historical sites that need to be preserved. At the upstream portion of the project, where the Rio Ojo de Agua flows through a mountainous ravine, a concrete crib dam was designed to contain large rocks and debris. Downstream of the crib dam, the water will flow under a high velocity flow regime through an existing historic railroad culvert/tunnel into a supercritical open channel and then into a covered channel beneath the existing roads to avoid impacts to adjacent historic buildings, park, and spring. The outfall of the covered channel will be near a newly constructed harbor at Aguadilla Bay. During these frequent storm events, these high velocity flows will most likely have an effect on navigation near the outlet and cause conditions for excessive scour. Therefore, energy dissipation of those velocities was investigated as well. A variety of hydraulic design criteria and one-dimensional (1D) and two-Dimensional (2D) hydraulic models were used to analyze and design the proposed project features. This paper will describe hydrologic and hydraulic analyses performed to design a project to reduce damages due to flooding and debris.