The Hani Rice Terraces System, based on gravity-flow irrigation, is one of the Globally Important Agricultural Heritage Systems (GIAHS) pilot sites selected by FAO in 2010. The water resource plays an important role in the sustainable development of this system. The value of water conserved by the forest is influenced by natural, economic and social factors. In this paper, the water quality, per capita water resources, per capita GDP and population density are chosen as indices to construct an index system for a comprehensive evaluation of water resources value. The weights of these indices are 0.443, 0.31, 0.141 and 0.106 respectively, which are determined by the analytic hierarchy process (AHP) method. The water resources value has been assessed by the fuzzy comprehensive evaluation model. The results show that the water resources value in the Hani Rice Terraces System is 4.25 RMB/m³. Evaluating the value of water resources in the Hani Rice Terraces System can provide a reference for ecological compensation, for raising public awareness of the importance of protecting the system, and ultimately achieving its sustainable development.

Stable isotopes of lake waters are widely used to identify the relative importance of hydrological processes on the lake water balance across the ungauged landscape via the coupled-isotope tracer model. The isotopic compositions of twenty shallow freshwater lakes across the mid-lower reaches of Yangtze floodplain (MLY) were investigated in January and May of 2018. The lake-specific input water (δ_I) and evaporation-to-inflow (E/I) ratios were estimated to explore the specific lake hydrology across the MLY. Results showed that distinct isotopic enrichment trends in May compared with those in January, which was indicative of stronger evaporation in May. The δ¹⁸O_I values of specific lakes exhibited large variability across the MLY, which may be related to the watershed properties, such as watershed area and elevation, and rainfall. The estimated E/I ratios of lakes across the MLY were below 1, which suggested that these lakes (code 1–15) are flood-dominated in the middle reaches of Yangtze River where lakes are susceptible to Three Gorges Dams regulations. By contrast, the relatively lower variability of lake E/I ratios were observed from the Yangtze River Delta (code 17–20) because these lakes with developed river network systems are highly exchanged by artificial regulation. Our investigation of lake types and corresponding isotopic evolution patterns are likely typical of other floodplain landscapes and their identification could be used to better predict hydrological responses to ongoing climate change and artificial regulations by dams.

Agricultural production is considered one of the most important sources of water quality deterioration in the Taihu Lake Basin, China. Crop farming, livestock & poultry breeding and aquaculture are primary agricultural non-point sources and their impacts on the water environment are, in most cases, evaluated separately. Therefore, it is a challenge for current research to consider all of the different agricultural non-point sources as a whole and assess their combined influence on the water environment. The purpose of this paper is to evaluate the conjoint impact that agricultural non-point sources such as crop farming, livestock & poultry breeding and aquaculture have had on the local water environment in the Taihu Lake Basin by taking Huzhou City of Zhejiang Province as a case study. To achieve this, a new, innovative approach named the “Waste Absorption Footprint” (WAF) is applied. The results show that nitrogen and phosphorus pollution generated by agricultural production are more serious than that of organic substances, while aquaculture and crop farming are more critical pollution sources compared with livestock and poultry breeding, and so they should be the focus of environmental management and pollution control initiatives. There is a regional discrepancy in the spatial distribution of agricultural non-point source pollution across counties and districts, which provides information for determining the key regions for the treatment of agricultural pollution. This study demonstrates that the WAF method can make a comprehensive assessment of the influence of agricultural production on the water environment and provide references for the control and management of agricultural non-point source pollution, which is of great importance for management of the water environment.