The most significant feature of the landscape of mountainous urbanized watersheds is complexity. The geomorphology, composition, and configuration have strong ties with river water quality. In this study, through redundancy analysis, we examined how landscape complexity measured at both landscape and class levels related to water quality within watersheds. The results indicate that water quality is closely associated with both the relief degree of the land surface and patch density at the landscape level. The river water quality of mountainous watersheds is better if the relief degree of the land surface is larger, though river water quality degradation is associated with higher fragmentation of the landscape. At the class level, a greater proportion of non-urban land use may contribute to better river water quality, as do better connectivity and moderate degrees of aggregation. Water quality is more likely to be degraded when the shape of residential land, public service, and commercial land is more complex. We conclude that, in mountainous urbanized watersheds, river water quality can be protected through land use planning and management by regulating a set of landscape metrics for complexity measures.

山区城市化流域景观的最重要特征是复杂性。地貌，成分和构造与河流水质有密切关系。在这项研究中，通过冗余分析，我们研究了如何在景观水平和等级水平上测量与流域内水质相关的景观复杂性。结果表明，水质与土地表面的起伏程度和景观水平上的斑块密度密切相关。如果土地表面的起伏程度较大，则山区流域的河水水质会更好，尽管河水水质的下降与景观的破碎化程度有关。在班级一级，更多的非城市土地使用可能有助于改善河流水质，更好的连通性和适度的聚合度。当居住用地，公共服务和商业用地的形状更加复杂时，水质可能会下降。我们得出的结论是，在山区城市化流域中，可以通过针对复杂性措施规范一套景观指标来通过土地利用规划和管理来保护河流水质。