Applying the NWS’s Distributed Hydrologic Model to Short-Range Forecasting of Quickflow in the Mahantango Creek Watershed

Abstract Accurate and reliable forecasts of quickflow, including interflow overland flow, are essential for predicting rainfall–runoff events that can wash off recently applied agricultural nutrients. In this study, we examined whether a gridded version the Sacramento Soil Moisture Accounting model with Heat Transfer (SAC-HT) could simulate forecast quickflow in two watersheds east-central Pennsylvania. Specifically, used Hydrology Laboratory–Research Distributed Hydrologic Model (HL-RDHM) software, which incorporates SAC-HT, to conduct 15-yr (2003–17) simulation 420-km 2 Mahantango Creek watershed WE-38, 7.3-km headwater interior basin. We directly calibrated HL-RDHM using hydrologic observations at outlet, while all grid cells within Creek, were indirectly scalar multipliers derived from basin outlet calibration. Using model, then assessed quality short-range (24–72 h) deterministic daily both over 2-yr period (July 2017–October 2019). At simulations showed low biases (PBIAS = 10.5%) strong agreement (KGE? 0.81) observations. scale, overestimated 69.0%) greater degree, but remained satisfactory 0.65). When forecasting, produced skillful (>90% Peirce Gerrity skill scores above 0.5) lead times significantly outperformed persistence forecasts, although gains slightly lower. Accordingly, by show promise informing operational decision-making agriculture. Significance Statement Daily runoff alert farmers have potential fertilizers manures. To gauge accurate reliable, monitoring data large one its tributaries evaluate short-term (1–3 days ahead) generated National Weather Service model. Results accuracy reliability generally improved as increased 1 3 days. Study findings highlight models provide useful inform