In this paper, the authors present a conceptual model for flood control planning in the Lower El Paso Valley. In the model, the river, canals and laterals and drains as well as underlying shallow groundwater aquifer are considered as integrated components. RiverWare was used to simulate the river flow. Return flows of drains and gains/losses of the river were estimated using time series transfer functions. Historic flow data was used to calibrate the numerical model. The river flow greatly depends on upper stream delivery and run-offs. Several flooding scenarios were evaluated under different delivery options.