하수관거정비사업에서 침입수․유입수 성과지표 활용을 위한 통계적 방법론에 관한 연구

Abstract

The operation performance of sewer rehabilitation projects conducted with Build-Transfer- Lease contract in Korea will be evaluated using the index of infiltration and inflow (I/I). Though I/I obtained at the fourth year should be initially evaluated based on the I/I values observed for the previous three years after the completion of sewer construction, the concrete methodology have not been proposed to rely on the so called 'performance evaluation committee'. This study suggests two statistical methodology to evaluate the I/I performance; the confidence interval method and the hypothesis-testing method. Assumed ten I/I values in each year for 20 years are used in this study. Two cases are analyzed and compared; case I to use as control data all I/I values for all years obtained before the evaluation year and case II to use I/I values for only 3 years before the evaluation year. As a result, case II tends to have relatively higher scores than case I, reflecting the low mean I/I values at the initial years.