The Urban Drainage and Flood Control District (UDFCD) maintains a network of rain and stream flow gauging stations as part of the ALERT Real-Time Flood Detection System. Originally, the District developed spreadsheet-based hydrologic models for major drainages in the Denver metro area utilizing real-time rainfall input to predict the timing and location of flood events in each modeled basin. These models have since been ported to a code-based environment using PL/pgSQL and an open-source PostgreSQL database.
Each basin model was developed using a similar approach, however specific methodologies differed between basins (e.g. methods for calculating effective precipitation). The number of sub-basins and whether reservoir routing was included also varied between each model.