Optimal operation of water reclamation facilities (WRFs) is critical for an indirect potable reuse (IPR) system, especially when the reclaimed water constitutes a major portion of the safe yield, as in the case of the Occoquan Reservoir located in Northern Virginia. This paper presents how a reservoir model is used for predicting future reservoir conditions based on the weather and streamflow forecasts obtained from the Climate Forecast System and the National Water Model. The resulting model predictions provide valuable feedback to the operators for correctly targeting the effluent nitrates using plant operations and optimization model called IViewOps (Intelligent View of Operations). The integrated models are run through URUNME, a newly developed integrated modeling software, and form a decision support system (DSS). The system captures the dynamic transformations in the nutrient loadings in the streams, withdrawals by the water treatment plant, WRF effluent flows, and the plant operations to manage nutrient levels based on the nitrate assimilative capacity of the reservoir. The DSS can provide multiple stakeholders with a holistic view for design, planning, risk assessments, and potential improvements in various components of the water supply chain, not just in the Occoquan but also in any reservoir augmentation-type IPR system.