Analysis of the Changes in the Water Yield Coefficient over the Past 50 Years in the Huang-Huai-Hai River Basin, China

Abstract

This study analysed the temporal and spatial changes in the water yield coefficient (WYC), which represents the ratio of the gross amount of water resources to precipitation. Factors such as precipitation, rainstorm days, rainless days, vegetation cover change, and land use/cover change were considered to determine the causes of these changes. The results led to the following conclusions: (1) The average annual WYC of the Huang-Huai-Hai River Basin is between 0.03 and 0.58, with an average value of 0.17, which is smaller than the national average WYC of 0.4. (2) Temporally, the WYC varied slightly, with the western part showing a negative trend and the eastern part showing a positive trend. The WYC is positively correlated with precipitation, rainstorm days, and the normalized difference vegetation index (NDVI) and negatively correlated with rainless days. However, a slower change in NDVI produced a faster change in WYC. In areas with land use types exhibiting a large evapotranspiration decrease, the rate of change in the WYC increased. (3) Spatially, the distribution is fairly regular, exhibiting a gradual increase from the northern part of the Yellow River Basin (WYC < 0.1) to the surrounding areas. When the WYC is correlated with precipitation, rainstorm days, rainless days, and NDVI, the R2 values of the linear fitting results are 0.98, 0.91, 0.96, and 0.73, respectively. The WYC is positively correlated with precipitation, rainstorm days, and vegetation coverage and negatively correlated with rainless days, but the correlation coefficient is greatly influenced by the precipitation characteristics and land use types. In areas featuring high proportions of land use types associated with high evapotranspiration, the average WYC is low.

Nature-Based Solutions in “Forest–Wetland” Spatial Planning Strategies to Promote Sustainable City Development in Tianjin, China

“…These data indicate that the water demand of the ecosystem is far from sufficiently met, and this can severely impede the maintenance of ecosystem services. The water yield coefficient (WYC) refers to the proportion of the total water resources in total precipitation [35]. A low WYC accounts for the low total water used in the ecological environment of Tianjin.…”

The Spatial and Temporal Assessment of the Water–Land Nexus in a Changing Environment: The Huang-Huai-Hai River Basin (China)

“…The gross domestic product (GDP), population, and cultivated land area of this region respectively account for 31%, 35%, and 38% of the whole country. However, only 7.2% of China's total water resources are in this region [6]. Climate change might have a crucial impact on water resource system vulnerability.…”

Spatiotemporal Variation in Actual Evapotranspiration and the Influencing Factors in Ningxia from 2001 to 2020

“…In the Xiliao River Plain, the NDVI and precipitation had different effects on ET from different land types [22]. NDVI, precipitation and temperature were the main factors affecting the actual ET in the Huang-Huai-Hai River Basin [23]. Vegetation cover had a great impact on the ET of grasslands in the Yili Valley [24].…”