روندیابی سیلاب و تخمین تلفات نشت در رودخانههای فصلی با حل همزمان معادلات جریان غیر ماندگار و نشت

Abstract

Abstract Due to transmission losses and lack of initial flow, flood routing in ephemeral streams is not possible with common methods and it is necessary the flood routing models have been developed for these streams. Therefore in this study a computer model for natural river cross section has been developed in that after linearization of partial differential equations of unsteady none uniform flow, they are solved by stagger method. This model can consider tributary flow and infiltration into river bed simultaneity. For estimation of transmission losses Muscat, Davis-Wilson, and Ingham methods have used and liked with unsteady flow equations in prepared model. Evaluation of model accuracy viewpoint programming, ability to simulate uniform flow and satisfying the continuity equation performed using 60 Garasoo River cross sections in a reach with about 18 km length. Lane’s hydrograph and Hughes Wash river properties were used to investigation model accuracy to estimate flow behavior and transmission losses. The result showed that prepared model can simulate uniform flow and satisfies continuity equation with height accuracy. Additionally when Muscat relation is used developed model can predict start and peak flood times correctly. Also transmission losses and volume of output hydrograph have predicted with maximum error less than 20 percent. While application of Davis – Wilson and Ingham relations showed unsatisfied result compare in situ measurement data. Keywords: Transmission losses, Ephemeral stream, Flood Routing, Saint-Venant equations