Hydrologic Regime Alteration Analysis of the Multi-Purpose Dam by Indicators of Hydrologic Alterations

Abstract

In this study, Hydrologic regime alterations(magnitude, magnitude and duration of annual extreme, frequency and duration of high and low pulse, rate and frequency of water condition changes, Range of Variability Approach) were analyzed by using Indicators of Hydrologic Alterations at the 11 major multi-purpose dam. The analysis result of the magnitude of monthly water conditions during drought season, inflow was 6.38 ㎥/sec ～ 39.84 ㎥/sec and outflow was 20.36 ㎥/sec ～ 49.43 ㎥/sec, was increased 1.84 % ～ 200.98 %. The analysis result of the magnitude of monthly water conditions during flood season, inflow was from 79.06 ㎥/sec to 137.12 ㎥/sec and outflow was from 65.32 ㎥/sec to 80.16 ㎥/sec, was decreased from 18.19 % to 40.39 %. The analysis result of the magnitude and duration of annual extreme, 1-day minimum was increased 82.86 % ～ 2,950 %, but 1-day maximum was decreased 34.78 % ～ 83.96 %. The analysis result of the frequency and duration of high and low pulse, low pulse count was decreased 29.67 % ～ 99.07 % and high pulse count was also decreased 4.60 % ～ 92.35 % after dam operation. Hydrograph rise rate was decreased 15.84 % ～ 79.31 % and fall rate was 1.97 % ～ 107.10 %. RVA of 1-day minimum was increased 0.60 ～ 2.67, also RVA of 1-day maximum was decreased 0.50 ～ 1.00.