Abstract: The transfer of water source conservation service value between different regions is the key content to be considered in the horizontal ecological compensation between the upstream and downstream of river basin. This transfer is dependent upon the basin's hydrological cycle path and river water transport. However, the current method for evaluating the transfer of water source conservation service value lacks an account of hydrological characteristics, thus requiring an enhancement of the rationality of evaluation results. Addressing this issue, the present study enhances the fracture point-field intensity model from two perspectives: transfer direction and transfer path. Firstly, the introduction of the river direction coefficient aids in assessing the hydraulic connection between the basin's upstream and downstream, as well as its main and tributary regions. Secondly, the assessment of water source conservation service transfer takes into account the hydrological characteristics of rivers, with particular application to the Yangtze River Basin (YRB), thereby improving the rationality and applicability of assessment outcomes. The findings reveal that the water source conservation capacity of the YRB in 2020 reached 1 153.85 billion m³, with the associated value of water source conservation service amounting to 1 195.38 billion yuan. In contrast to the evaluation results obtained from existing models, the present enhanced fracture point-field intensity model underscores the transfer of water source conservation service value from upstream to downstream, and amplifies the transfer intensity and range. Within the YRB, the water source conservation service value transferred from Sichuan ranks the top, followed by Jiangxi, Hunan, Guizhou, Hubei, Anhui, Chongqing, Yunnan, Zhejiang, Qinghai, Shaanxi, Guangxi, Xizang, and Henan in descending order; the service value received by Yunnan is the largest, followed by Anhui, Hubei, Chongqing, Jiangsu, Hunan, Sichuan, Shanghai,and Xizang in descending order.

Key words: water source conservation service, spatial transfer, fracture point-field intensity model, InVEST model, Yangtze River Basin