Correction of bifurcated river flow measurements from historical data: Paving the way for the Teesta water sharing treaty

Abstract

In this paper, we consider an estimation problem arising in the measurement of bifurcated flow of the Teesta, a trans-boundary river flowing through India and Bangladesh. The location of measurement is an Indian Barrage, where a part of the flow is diverted from the main stream to a canal. The flows through the two channels are regulated by different control structures and are measured indirectly from the height of the water level and the dimensions of the control structures. The computational formula for the measurement involves a hydrological constant used as a multiplier. Empirical findings indicate that incorrect multipliers are currently used in the computational formula for the two channels. For implementing any water sharing treaty between the two countries, the measurements need to be brought to a common scale. For this purpose, we present a model with carefully considered assumptions to estimate the correction factor. The model permits diagnostic tests for validation of the assumptions. We provide a nonparametric and consistent estimator of the desired factor.

Analysis of historical flow data shows that a main stream flow measured as 100 cumec would be measured as 76 cumec if it is diverted through the canal. Adjustment of emerging measurements through this finding would help the governments of India and Bangladesh to effectively implement and monitor any water sharing agreement.