Determining the hydrological responses to climate variability and land use/cover change in the Loess Plateau with the Budyko framework

Abstract

• Elasticities of Q and R c to climate variability and catchment characteristic were derived.• Contributions of climate variability and land use/cover changes to reductions of Q and R c were determined.• Relationship between ecological restoration and hydrological responses was quantified. Understanding and quantifying the impacts of land use/cover change and climate variability on hydrological responses are important to the design of water resources and land use management strategies for adaptation to climate change, especially in water-limited areas. The elasticity method was used to detect the responses of streamflow and runoff coefficient to various driving factors in 15 main catchments of the Loess Plateau, China between 1961 and 2009. The elasticity of streamflow (Q) and runoff coefficient (R c ) to precipitation (P), potential evapotranspiration (E 0 ), and catchment characteristics (represented by the parameter m in Fu's equation) were derived based on the Budyko hypothesis. There were two critical values of m = 2 and E 0 /P = 1 for the elasticity of Q and R c . The hydrological responses were mainly affected by catchment characteristics in water-limited regions (E 0 /P N 1), and in humid areas (E 0 /P b 1), climate conditions played a more important role for cases of m N 2 whereas catchment characteristics had a greater impact for cases of m b 2. The annual Q and R c in 14 of the 15 catchments significantly decreased with average reduction of 0.87 mm yr −1 and 0.18% yr −1 , respectively. The mean elasticities of Q to P, E 0 and m were 2.66, −1.66 and −3.17, respectively. The contributions of land use/ cover change and P reduction to decreased Q were 64.75% and 41.55%, respectively, while those to decreased R c were 75.68% and 32.06%, respectively. In contrast, the decreased E 0 resulted in 6.30% and 7.73% increase of Q and R c , respectively. The contribution of land use/cover changes was significantly and positively correlated with the G R A P H I C Contents lists available at ScienceDirectScience of the Total Environment j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / s c i t o t e n v increase in the percentage of the soil and water conservation measures area (p b 0.05). The R c significantly and linearly decreased with the vegetation coverage (p b 0.01). Moreover, the R c linearly decreased with the percentage of measures area in all catchments (eight of them were statistically significant with p b 0.05).

Spatio-temporal patterns of the effects of precipitation variability and land use/cover changes on long-term changes in sediment yield in the Loess Plateau, China

“…Notable decreases in sediment yields have been observed in approximately 50 % of the world's rivers (Walling and Fang, 2003;Syvitski et al, 2005). Many studies have investigated the dynamics of streamflows and sediment yields at different spatial and temporal scales (Mutema et al, 2015;Song et al, 2016;Gao et al, 2016). In addition to climate variability, LUCC, soil and water conservation measures (SWCMs) and construction of reservoirs and dams have substantially contributed to the sediment load reductions (Walling, 2006;Milliman et al, 2008;Wang et al, 2011).…”

Spatial Heterogeneity in Sensitivity of Evapotranspiration to Climate Change

“…In accordance with the Budyko space of (E/P) and (E 0 /P), there is an energy limit (i.e., y = x) and a water limit (i.e., y = 1), which are based on the fact that E<P and E<E 0 [24][25][26]. In many conditions, as shown in Fig.…”

Decreased Streamflow in the Yellow River Basin, China: Climate Change or Human‐Induced?

“…where n is the underlying surface parameter or land use and land cover change (LUCC) [19,23,24]. Based on the water balance equation, R = P − E, we have R = f (P, E 0 , n).…”

“…The underlying parameter, n, is known to provide a good proxy for human-induced streamflow changes [12,24], but the impact of human activities on streamflow changes or hydrological processes are complex in both space and time. Generally, fluvial tributaries are grouped based on the different degrees of impacts their underlying features have on streamflow [12,34], especially different land use and land cover changes.…”

“…Liang et al [20] evaluated the effects of ecological conservation activities for the period 1960-2009 on streamflow, reporting that the fractional contribution of climate change to streamflow changes was 38% and that of ecological conservation activities, which are after all a type of human activity, were 62%. Gao et al [24] analyzed the impacts of climate change and human activities on streamflow on the Loess Plateau, suggesting that the fractional contributions of changes in underlying watershed properties and precipitation were 64.75% and 41.55%, respectively. Compared to these earlier studies, the current study includes more meteorological factors and a wider range of human activities beyond simply land use and land cover by examining changes in forest land, cropland and water areas, population density, and GDP, as well as providing a more detailed picture of both climate-and human-induced impacts on hydrological processes.…”