Instantaneous Unit Hydrograph Evaluation for Rainfall-Runoff Modeling of Small Watersheds in North and South Central Texas

• Published in: Journal of irrigation and drainage engineering Vol. 132; no. 5; pp. 479 - 485
• Main Authors: Cleveland, Theodore G, He, Xin, Asquith, William H, Fang, Xing, Thompson, David B
• Format: Journal Article
• Language: English
• Published: Reston, VA American Society of Civil Engineers 01.10.2006
• Subjects: Agricultural and forest climatology and meteorology. Irrigation. Drainage; Agronomy. Soil science and plant productions; Biological and medical sciences; Freshwater; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; hydrologic models; Irrigation. Drainage; mathematical models; rain; stormwater; TECHNICAL PAPERS; watersheds; Texas; United States; North America; America; USA, Texas; Hydrographs; Rain; Runoff; Texas; Watershed; Water engineering; Rainfall; Runoff water; Modeling; Flow diagram
• ISSN: 0733-9437; 1943-4774
• DOI: 10.1061/(ASCE)0733-9437(2006)132:5(479)

Data from over 1,600 storms at 91 stations in Texas are analyzed to evaluate an instantaneous unit hydrograph (IUH) model for rainfall-runoff models. The model is fit to observed data using two different merit functions: a sum of squared errors function, and an absolute error at the peak discharge time ( Qp MAX) function. The model is compared to two other models using several criteria. Analysis suggests that the Natural Resources Conservation Service Dimensionless Unit Hydrograph, Commons’ Texas hydrograph, and the Rayleigh IUH perform similarly. As the NRCS and Commons’ models are tabulations, the Rayleigh model is an adequate substitute when a continuous model is necessary. The adjustable shape parameter in the Rayleigh model does not make any dramatic improvement in overall performance for these data, thus fixed shape hydrographs are adequate for these watersheds.