Dynamic rating method for computing discharge from time-series stage data

First posted June 8, 2022 For additional information, contact: Director, Central Midwest Water Science Center U.S. Geological Survey405 North Goodwin Urbana, IL 61801Contact Pubs Warehouse Ratings are used for a variety of reasons in water-resources investigations. The simplest rating relates discharge to the stage river. From pure hydrodynamics perspective, all rivers and streams have some form hysteresis relation between because unsteady flow as flood wave passes. Simple ratings unable represent stage/discharge relation. A dynamic method is capable capturing owing variable energy slope caused by momentum pressure.A developed compute from compact channel geometry, referred DYNMOD, previously has been through simplification one-dimensional Saint-Venant equations. method, which accommodates compound DYNPOUND, similar part this study. DYNMOD DYNPOUND methods were implemented Python programming language. Discharge time series computed with implementations then compared simulated discrete measurements made at Survey streamgage sites.Four sets created using simulation software geometry compare results both full shallow water DYNPOUND. outperformed four scenarios. minimum maximum mean squared logarithmic error (MSLE) 2.75×10−2 3.40×10−2, respectively. MSLE 2.51×10−7 1.91×10−4, respectively.The calibrated six sites observed data collected sites. calibration objective each site was minimize respect discharge. site, included field within selected year. failed three fails when implementation returns nonfinite value step. Because values following steps dependent on previous step, that follow. complete series, 2.19×10−3 9.77×10−3. ranged 3.70×10−3 1.25. an event-based period DYNMOD-computed had range 2.76×10−3 3.14×10−2. 3.64×10−3 7.23×10−2. Although outperforms under consideration, therefore, more robust than method. Improvements may improve accuracy