Harmonious Development between Socio-Economy and River-Lake Water Systems in Xiangyang City, China

River-lake water systems (RLS) are important carriers for matter transformation and energy transmission. Influenced by accelerated social and economic development, the structural, functional, and environmental states of RLS have been seriously damaged. It is an important problem for human beings to coordinate the contradiction between socio-economic development and the protection of RLS. In order to quantitatively study the harmonious relationship between socio-economic development and the state of RLS, the harmony theory method was used to analyze the degree of harmonious development between socio-economy and RLS in this study taking Xiangyang City as an example, and formulating corresponding harmonious optimization schemes. The results indicate that: (1) the state of RLS had a relatively small change during 2009–2014, and its spatial distribution shows a decreasing trend with the Han River as the central axis decreases on both of its sides; (2) before 2011, the driving force of socio-economic development in Xiang yang City mainly originated in the peripheral regions such as Laohekou City, Zaoyang City, and Gucheng County, but after 2011, it migrated rapidly towards Downtown, and reached the maximum in 2014; (3) when the influence of regional socio-economic development on RLS is small, socio-economic development is the main factor driving the change of the overall harmonious development degree of socio-economy and RLS. However when the influence is big, it is combined, driven by socio-economic development and the state of RLS; (4) the main factors affecting the overall harmonious degree of socio-economy and RLS in Xiangyang City include: river length, standard ratio of water quality, water consumption per capita, reservoir regulation capability, farmland irrigation water consumption per Mu (Mu is an area unit in China, 1 Mu approximately equals to 666.67 m2), and sewage treatment rate. This study can provide a reference for the future analysis of the harmonious development between socio-economy and RLS, as well as in formulating corresponding harmonious optimization schemes in China and other countries in a similar situation.