Doña Ana County Flood Commission, NM: Drainage Master Plans
The DACFC hired Smith to prepare a DMP for the communities of Chamberino, Salem, Doña Ana, and Mesquite areas. These communities have experienced poor drainage and serious historic flooding. These DMPs included a storm runoff model and system with associated recommendations for capital improvements, both in short and long term. The DMPs required creating hydrologic models that simulated the 10 (10% chance) and 100 (1% chance) year storm events. All storm events were modeled at high antecedent moisture conditions and using type II-75 storm distribution. Potential flood hazard zones were identified. The proposed drainage model included all ponding features (1 acre-feet or more in volume) and that included conveyance (10 cfs or more) features in, and adjacent to, areas that impacted the communities. 2D surface water models were prepared using HEC-RAS V5.0.3 for the Doña Ana and Mesquite DMPs. The DMPs outlined the problem areas and system deficiencies and general methods required and specific capital projects and strategies that needed to be implemented to improve drainage and increase the infrastructure’s ability to control flooding. All facilities were evaluated relative to their compliance established standards, including FEMA, State, and local standards. NPDES regulations were considered as well. The hydrologic models were prepared using HEC-HMS v4.2.1. The hydraulic model was prepared using HEC-RAS v5.0.3. Smith made the project deliverables compatible with the current County GIS software (ESRI Arc GIS 10.4) and AutoCAD.