INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 1, No 7, 2011 © Copyright 2010 All rights reserved Integrated Publishing Association Research article ISSN 0976 – 4402 Received on February, 2011 Published on April 2011 1459 Synthesis of flow series of tributaries in Upper Betwa basin Chaube U.C 1 , Shakti Suryavanshi 1 , Lukman Nurzaman 2 , Ashish Pandey 1 1 Department of Water Resources Development and Management, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India 2 Trainee Officer, Indonesia suryavanshi.shakti@gmail.com ABSTRACT In this study, HYMOS 4.0 software has been used to synthesize monthly flow series for thirteen years in each of the twelve tributary subcatchments of the Betwa basin up to Rajghat. The HYMOS 4.0 software uses Sacramento model to synthesize discharge data. Monthly rainfall data for 14 stations from 1980 to 1992; ten daily discharge data for 2 stations (Basoda and Rajghat) from 1980 to 1992 and daily evaporation data for 1 station (Sagar) from 1980 to 1992 has been used as input in the Sacramento Model. The Coefficient of determination and NashSutcliffe Efficiency between observed flow at the Basoda and sum of six tributaries synthesized discharge were found to be 0.862 and 0.837respectively. Similarly, The Coefficient of determination and NashSutcliffe Efficiency between observed flow at the Rajghat and sum of twelve tributaries synthesized discharge were 0.841 and 0.839 respectively. The difference between observed and synthetic discharge of Bina basin varies from 1.79% to 11.62%. High values of Coefficient of determination and Nash–Sutcliffe efficiency indicate that model can be successfully used for flow simulation in the Betwa basin. Keywords: River basin planning, HYMOS, monthly simulation, synthetic discharge, water balance, water allocation, water utilization, Betwa River. 1. Introduction River basin development planning and management support integration of watershed, groundwater, land use, river regulation (by dams, barrages), welfare improvement, healthcare, and most aspects of development (Gourbesville, 2008). An obvious and often laborious first step in the analysis, to support such planning and management, is the collection and processing of available data on the physical properties of the system (Linden, 1989). Thus, in planning and managing the water resources of a river basin, simulation model is needed to estimate benefits and other impacts of an alternative and scenario development. Hydrological Modeling System (HYMOS) is a processing system for hydrometeorological data which arranges a convenient structuring of data and provides a large number of tools for processing of data meeting the international standards, (WMO, 1985). The simulation of the rainfall runoff process in a catchment aims at: fillingin and extension of discharge series; generation of discharge series from observed rainfall; real time flood forecasting; and determination of the influence of a changing land/water use. There are ten River basins (Betwa, Mahi, Chambal, Sind, Ken, Tons, Sonn, Narmada, Wainganga and Tapi) in Madhya Pradesh which provides irrigation and other benefits to the state. A large number of medium and minor irrigation projects have been developed in the state. However, these irrigation facilitating river basins are in a poor state, primarily due to