Estima ted Econom ic L osses of O il Pollution of W e ihe R iver ZHANG Xiao2Juan, WANG Zhi2L iang (North China Institute ofW ater Conservancy and Hydroelectric Power, Zhengzhou 450011, China) Abstract: To estimate the direct econom ic losses of areas along the Yellow R iver in Henan Province caused by oil sp ill in the southern of W eihe R iver in Shaanxi in 2009, the calculation of econom ic loss