제주도 하천 관측자료 기반 유출특성 매개변수 도출 및 홍수유출량 산정

Abstract

There were limits to apply the flood discharge calculation method, which is domestically applied, directly in the streams of Jeju Island that has different hydrological?geological characteristics from interior lands and the characteristics of Jeju Island are not being reflected because domestic methods are being directly applied Jeju Island stream master plans. In this study, discharge characteristic parameters are deducted based on scene observation data during rainfalls to calculate the flood discharge of Jeju Island streams. Subject to Jeju Island Han Stream 2nd Dongsan bridge during runoff, mobile microwave water surface current meter, LSPIV, and ADCP were used for discharge observation and the mean areal rainfall was applied by developing the isohyetal method by transforming the Thiessen polygon method. Initial abstraction of NRCS-CN method to calculate effective rainfall was estimated by using observations, and mapping analysis was used to deduct Muskingum parameters , . By setting the range of Clark unit hydrograph parameters and runoff curve number , the optimum combination(discharge after no rainfall: , KravenⅡ, Sabol, discharge after antecedent rainfall: , KravenⅡ, Sabol) was calculated. Results were deducted by categorizing events of discharge occurring after no rainfall and after antecedent rainfall. Calculating discharge by the method used in existing stream master plans and the method applied in this study, mean areal rainfall reduced 3.7～8.1%, time of concentration by Clark unit hydrograph method(Tc), peak leakage by discharge constant(K) each reduced 2.42～6.87% and 12.5～28.3%, and it was analyzed that total abstraction had increased about 25～35% due to initial abstraction. To calculated flood discharge of Jeju Island streams more accurately in the future, it is thought that development of various parameter deduction equations reflecting hydrological characteristics of Jeju Island and stream discharge characteristic analysis based on basic data is required.