洪災防治之效益－－以基隆河整治為例

FLOOD CONTROL BENEFITS: A CASE STUDY OF THE KEELUNG RIVER BASIN

本文應用二階段特徵租金法估計基隆河整治後， 原洪災機率超過0.5%之地區全面降至0.5% 時之家戶總消費者剩餘， 並計算基隆河整治計畫之益本比。本研究發現基隆河整治計畫完成後， 洪災機率由目前水準全面降至0.5% 之總消費者剩餘為每年98.66 億元； 假設各淹水區房屋之平均餘命為30 年， 每年總消費者剩餘維持不變， 折現率為0.025、0.05、0.075、0.1 四種情況， 則基隆河整治總效益之現值分別為2，082.25 億元、1，532.92 億元、1，176.82 億元、937.47 億元， 益本比分別為2.87、2.12、1.62、1.29。

This paper employs a two-stage hedonic rent approach to estimate the benefits of flood control in the Keelung River Basin and to calculate the benefitcost ratio of the Keelung River flood control project. The major findings of this study include: (1) The annual total benefit of reducing flooding probability from current levels to 0.5%, in terms of consumer surplus, is NT$ 9,866 million. (2) Assuming that the average life expectancy of houses in the flooding areas is 30 years, the annual consumer’s surplus estimated stays the same, and the discounting rates are 0.025, 0.05, 0.075, and 0.1, respectively. Then, the estimated total benefits of the Keelung River flood control project are NT$ 208,225million, NT$ 153,292 million, NT$ 117,682 million, and NT$ 93,747million, respectively. The estimated benefit-cost ratios are 2.87, 2.12, 1.62, and 1.29, respectively.