Versions of the drainage area ratio method for transfer of daily or monthly stream flows

Abstract

By the drainage-area ratio method, the daily or monthly flows gauged at a nearby station are transferred to an ungauged section where a dam is to be built by multiplying them by the real number resulting from raising the ratio of the drainage areas of the dam section and of the station to an exponent (n). Commonly n is taken as 1. First, using the daily flows of two stations nearby the dam section on the same stream or on a neighboring stream, having a common N-year long gauging record, it is proposed that 365 linear regressions be fitted to N pairs of 365 daily flows, and relating them to the drainage area ratios, daily flows at the dam section be computed using 365 n's each belonging to a day. Next, by the same analytical model applied to the monthly flows, 12 monthly flows are transferred to the dam section. Five versions of the drainage-area ratio method, three of which with constant exponents, are investigated, and the last one with n = 1 is found to be relatively the worst.

Simulation Models for Hydro-Electric Energy by Steady-Rate and Night-Shift-Pumped-Storage Operations

“…There are not any gauging stations close enough to the embankments of the other seven dams. By investigating the beginning and ending record lengths of the nearest-by gauging stations around those seven dams and by choosing the most suitable stations, the 35-year-long gauged daily flows are approximately computed for them again by the drainage-area-ratio formula, by the procedure proposed in a relevant study [20].…”