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Prof. Jintao Liu
State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing, China

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Research Keywords & Expertise

0 Hillslope Hydrology
0 Alpine Hydrology
0 Hydrologic similarity and classification
0 Runoff processes and modelling
0 Digital drainage algorithm

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Runoff processes and modelling
Soil thickness evolution

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Original paper
Published: 21 August 2021 in Stochastic Environmental Research and Risk Assessment
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In mountainous basins with low anthropogenic influences, runoff generation varies geographically, and it is essential to investigate the hierarchical controls of geographical features on hydrological responses. In this study, a stepwise clustering scheme was proposed to classify 64 mountainous basins located in eastern China into 11 basin groups and 3 hierarchies according to the geographical features of rainfall, topography and geomorphology, and soil and geology. Then, the leave-one cross validation assessing the transferability of hydrological model parameters was used to measure the hydrological similarity among basins and within each group, and to examine the quality of classification. The results showed that 92% of all basins had other basins with high similarity. The overall similarity of the hydrological responses in the 11 basin groups was quite different. The basin groups driven by heavy rainfall events tended to form highly similar runoff processes. Basins in the groups with steeper terrain, more convergent slopes, rounder shapes, and better vegetation cover also exhibited a higher overall hydrological similarity. Then, according to the discharge characteristics, the controlling role and intensity of different hierarchical geographical features on hydrological responses were quantitatively represented. In 6 of the 11 basin groups, rainfall features (e.g. average monthly rainfall and rainstorm characteristics) were collectively the primary controlling factor of runoff, while topographic and geomorphic features were the second most important factor. Rainfall features were the second most important controlling factor in the other four basin groups. However, the controlling role of soil and geological features on hydrological responses appeared to be unstable. In summary, these findings could provide guidance for hydrological predictions in ungauged basins in diverse geographical environments.

ACS Style

Yaqian Yang; Jintao Liu; Shuang Yang; Ruimin He. Understanding the hierarchical controls of geographical features on hydrological responses in humid mountainous areas through a stepwise clustering scheme. Stochastic Environmental Research and Risk Assessment 2021, 1 -20.

AMA Style

Yaqian Yang, Jintao Liu, Shuang Yang, Ruimin He. Understanding the hierarchical controls of geographical features on hydrological responses in humid mountainous areas through a stepwise clustering scheme. Stochastic Environmental Research and Risk Assessment. 2021; ():1-20.

Chicago/Turabian Style

Yaqian Yang; Jintao Liu; Shuang Yang; Ruimin He. 2021. "Understanding the hierarchical controls of geographical features on hydrological responses in humid mountainous areas through a stepwise clustering scheme." Stochastic Environmental Research and Risk Assessment , no. : 1-20.

Hpeye
Published: 16 June 2021 in Hydrological Processes
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ACS Style

Xuhui Shen; Jintao Liu; Wanjie Wang; Xiaole Han; Jie Zhang; Guofang Li; Xiaopeng Li; Yue Shi. A novel physical model demonstrating critical zone structure and flow processes in headwaters for teaching and research purposes. Hydrological Processes 2021, 35, e14259 .

AMA Style

Xuhui Shen, Jintao Liu, Wanjie Wang, Xiaole Han, Jie Zhang, Guofang Li, Xiaopeng Li, Yue Shi. A novel physical model demonstrating critical zone structure and flow processes in headwaters for teaching and research purposes. Hydrological Processes. 2021; 35 (6):e14259.

Chicago/Turabian Style

Xuhui Shen; Jintao Liu; Wanjie Wang; Xiaole Han; Jie Zhang; Guofang Li; Xiaopeng Li; Yue Shi. 2021. "A novel physical model demonstrating critical zone structure and flow processes in headwaters for teaching and research purposes." Hydrological Processes 35, no. 6: e14259.

Preprint content
Published: 04 March 2021
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The soil thickness is the key controlling factor of local hydrology and geomorphologic characteristics. The accuracy, reliability and coverage of soil thickness map are required for reliable application. Though with quite distinct structures, models for simulating soil thickness take modern topographic data (normally digital elevation model, DEM) as one of the most important inputs. Understanding the effect of grid resolution on soil thickness prediction and selecting an appropriate resolution is crucial for the macro-scale modeling. In this study, we further explored the relationship between topographic resolution and simulation accuracy of soil thickness, and propose a new method to determine the optimal simulation resolution. A series of abstract hillslopes with different terrain noise and terrain complexity were construct and different resolutions of DEM were generated. We used a simple geomorphic based model to calculate topographic index (slope, aspect and curvature) and soil thickness. The results show that the truncation error and noise of DEM will propagate during the simulation process. Furtherly, the correlation curve between DEM resolution and the simulation error of soil thickness is a hook curve. The shape of the curve is mainly controlled by two factors, terrain noise and terrain complexity. By fitting the correlation curve of all hillslopes, the curve can be predicted by them, and the resolution corresponding to the error minimum be found out, which can be called the optimal simulation resolution of the soil thickness prediction model.

ACS Style

Yangyang Liu; Jintao Liu; Wei Zhao. How does DEM error impact the optimal grid resolution of soil evolution simulation? 2021, 1 .

AMA Style

Yangyang Liu, Jintao Liu, Wei Zhao. How does DEM error impact the optimal grid resolution of soil evolution simulation? . 2021; ():1.

Chicago/Turabian Style

Yangyang Liu; Jintao Liu; Wei Zhao. 2021. "How does DEM error impact the optimal grid resolution of soil evolution simulation?" , no. : 1.

Preprint content
Published: 04 March 2021
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Equipped with complex terrain structure, physical models provide an alternative way in understanding and modeling how critical zone shapes hydrologic processes in headwaters for research and education in hydrology. However, this type of physical models is limited by frustrating rain-erosion or gully-erosion. Herein, in order to replace the real-world backfilling soil, we drew on the experience of normal concrete workmanship and adjusted the raw material’s proportion for three times. And it is found that saturated hydraulic conductivity (SHC) and field moisture capacity (FMC) are both well correlated with bulk density (BD) for the developed materials in three cases. Thereby, based on the strongest correlation (R2=0.75) between SHC and BD, two-layer alternative soil has been designed through altering BD in the physical model with complex terrain. The SHC values of alternative soil are close to that of the natural soil while the FMC values are far lower. Additionally, the non-uniform scaling of bedrock terrain was applied for the convenience of teaching and construction by zooming out a steep 0.31-ha zero-order basin 130 times horizontally and 30 times vertically. And multiple observation items, including free water level, temperature and humidity of soil, as well as outflow could provide potential opportunity to explore the role of single or combined critical zone’s element in modulating streamflow. We’d like to share this effective tool to facilitate the development of critical zone science and enrich experimental teaching methods.

ACS Style

Xuhui Shen; Jintao Liu; Wanjie Wang; Xiaole Han; Jie Zhang; Guofang Li. A physical model demonstrating critical zone structure and flow processes in headwaters. 2021, 1 .

AMA Style

Xuhui Shen, Jintao Liu, Wanjie Wang, Xiaole Han, Jie Zhang, Guofang Li. A physical model demonstrating critical zone structure and flow processes in headwaters. . 2021; ():1.

Chicago/Turabian Style

Xuhui Shen; Jintao Liu; Wanjie Wang; Xiaole Han; Jie Zhang; Guofang Li. 2021. "A physical model demonstrating critical zone structure and flow processes in headwaters." , no. : 1.

Preprint content
Published: 04 March 2021
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Slope units have great potential for hydrological and geomorphological studies, especially for landslide susceptibility modelling. Digital Elevation Models are widely used to delineate slope units by connecting drainage and divide lines. However, it is difficult to estimate reasonable scale thresholds for drainage and divide lines, which limits the application of slope units. Most existing methods for slope unit delineation determine the scales manually. Recently, several automatic methods have been proposed, but these methods encounter the problem of low computing efficiency for large-scale region. In this study, a new efficient method is presented for automatic slope unit delineation. Similar to an existing method, our method divides the region into several sub-basins and delineate slope units for every sub-basin independently. Within a sub-basin, grid cells are classified into massive units, and neighboring units are merged according to several strategies when aspect homogeneity can be satisfied. The new method is tested in Yarlung Tsangpo Basin, southeastern Tibetan Plateau. This basin has a large area of nearly 250 000 km2, and can be divided into nearly 340 000 slope units within 3 hours using a general personal computers. The rationality of our method is proved by both visual and quantitative assessments.

ACS Style

Pengfei Wu; Jintao Liu. An efficient method for automatic slope unit delineation from a huge region. 2021, 1 .

AMA Style

Pengfei Wu, Jintao Liu. An efficient method for automatic slope unit delineation from a huge region. . 2021; ():1.

Chicago/Turabian Style

Pengfei Wu; Jintao Liu. 2021. "An efficient method for automatic slope unit delineation from a huge region." , no. : 1.

Preprint content
Published: 03 March 2021
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Preferential flow (PF)-dominated soil structure is often considered a unique system consisting of micropores and macropores and thus supposed to provide dual-pore filtering effects on hydrological signals, through which smoothing effects are likely to be stronger for matrix flow and weaker for PF via macropores. By using time series of hydrological signals (precipitation, canopy interception, throughfall, soil moisture, evapotranspiration, water storage in soil and groundwater, and catchment discharge) propagating through the Shale Hills Catchments and representative soil series, the filtering effects of the catchment and soil profiles were tested through the wavelet analysis. The hypothesized dual-pore-style filtering effects of the soil profile were also confirmed through the coherence spectra and phase differences, rendering them applicable for possible use as “fingerprints” of PF to infer subsurface flow features. We found that PF dominates the catchment’s discharge response at the scales from three to twelve days, which contributes to the catchment discharge mainly as subsurface lateral flow at upper or middle soil horizons. Through subsurface PF pathways, even the hilltop is likely hydrologically connected to the valley floor, building connections with or making contributions to the catchment discharge. This work highlights the potential of wavelet analysis for retrieving and characterizing subsurface flow processes based on the revealed dual-pore filtering effects of the soil system.

ACS Style

Hu Liu; Wenzhi Zhao; Yang Yu; Li Guo; Jintao Liu. Subsurface Preferential Flow Enhances Hydrological Connectivity in the Shale Hills Catchment: Perspective from Wavelet-based Analysis. 2021, 1 .

AMA Style

Hu Liu, Wenzhi Zhao, Yang Yu, Li Guo, Jintao Liu. Subsurface Preferential Flow Enhances Hydrological Connectivity in the Shale Hills Catchment: Perspective from Wavelet-based Analysis. . 2021; ():1.

Chicago/Turabian Style

Hu Liu; Wenzhi Zhao; Yang Yu; Li Guo; Jintao Liu. 2021. "Subsurface Preferential Flow Enhances Hydrological Connectivity in the Shale Hills Catchment: Perspective from Wavelet-based Analysis." , no. : 1.

Preprint content
Published: 03 March 2021
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In the mountainous basins with less anthropogenic influence, the hydrological function is mainly affected by climate and landscape, which makes it possible to measure hydrological similarity indirectly by geographical features. Due to the mechanisms of runoff generation can vary geographically, in this study, a simple stepwise clustering scheme was proposed to explore the role of geographical features at different spatial hierarchy in indicating hydrological response. Research methods mainly include (1) Stepwise regression was used to quantitatively show the correlation between 35 geographical features and 35 flow features and identify the important explanatory variables for hydrological response; (2) 64 basins were divided by stepwise clustering scheme, and the overall ability of the scheme to capture hydrological similarity was tested by comparing the optimal parameters; (3) The hydrological similarity of basin groups was measured by the leave-one cross validation of hydrological model parameters. The results showed that: (1) Rainfall features, elevation, slope and soil bulk density are the main explanatory variables. (2) The NSE of basin groups based on stepwise clustering is 0.64, reaches 80% of the optimal parameter sets (NSE=0.80). The NSE of 90% basins is greater than 0.5, 80% is greater than 0.6, and 49% is greater than 0.7. (3) In humid areas, the hydrological responses of the basins with more uniform monthly rainfall and more abundant summer rainfall are more similar, e.g., the NSE of Class 4 is 0.77. Under similar rainfall patterns, the hydrological responses of the basins with higher average altitude, greater slope, more convergent of shape and richer vegetation are more similar, e.g., the NSE of Class 3-2 is 0.72 and that of Class 1-2 is 0.70. In the case of similar rainfall patterns and landforms, the hydrological responses of the basins with smaller soil bulk density are more similar, e.g., the NSE of Class 3-2-2 is 0.80. In conclusion, the stepwise clustering enhances the interpretability of basin classification, and the effect of different geographical features on hydrological response can show the applicability of hydrological simulation in ungauged basins.

ACS Style

Yaqian Yang; Jintao Liu. Understanding the role of different geographical features in the hydrological response of humid mountainous areas through a stepwise clustering scheme. 2021, 1 .

AMA Style

Yaqian Yang, Jintao Liu. Understanding the role of different geographical features in the hydrological response of humid mountainous areas through a stepwise clustering scheme. . 2021; ():1.

Chicago/Turabian Style

Yaqian Yang; Jintao Liu. 2021. "Understanding the role of different geographical features in the hydrological response of humid mountainous areas through a stepwise clustering scheme." , no. : 1.

Preprint content
Published: 03 March 2021
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Highly intermittent rivers are widespread on the Tibetan Plateau and deeply impact the ecological stability and social development downstream. Due to the highly intermittent rivers are small, seasonal variated and heavy cloud covered on the Tibetan Plateau, their distribution location is still unknown at catchment scale currently. To address these challenges, a new method is proposed for extracting the cumulative distribution location of highly intermittent river from Sentinel-1 time series in an alpine catchment on the Tibetan Plateau. The proposed method first determines the proper time scale of extracting highly intermittent river, based on which the statistical features are calculated to amplify the difference between land covers. Subsequently, the synoptic cumulative distribution location is extracted through Random Forest model using the statistical features above as explanatory variables. And the precise result is generated by combining the synoptic result with critical flow accumulation area.  The highly intermittent river segments are derived and assessed in an alpine catchment of Lhasa River Basin. The results show that the the intra-annual time scale is sufficient for highly intermittent river extraction. And the proposed method can extract highly intermittent river cumulative distribution locations with total precision of 0.62, distance error median of 64.03 m, outperforming other existing river extraction method.

ACS Style

Junyuan Fei; Jintao Liu. Extracting the cumulative distribution location of highly intermittent river from Sentinel-1 time series in an alpine catchment on the Tibetan Plateau. 2021, 1 .

AMA Style

Junyuan Fei, Jintao Liu. Extracting the cumulative distribution location of highly intermittent river from Sentinel-1 time series in an alpine catchment on the Tibetan Plateau. . 2021; ():1.

Chicago/Turabian Style

Junyuan Fei; Jintao Liu. 2021. "Extracting the cumulative distribution location of highly intermittent river from Sentinel-1 time series in an alpine catchment on the Tibetan Plateau." , no. : 1.

Journal article
Published: 27 October 2020 in Water Resources Research
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Preferential flow (PF)-dominated soil structure is often considered a unique system consisting of micropores and macropores and thus supposed to provide dual-pore filtering effects on hydrological signals, through which smoothing effects are likely to be stronger for matrix flow and weaker for PF via macropores. By using time series of hydrological signals (precipitation, canopy interception, throughfall, soil moisture, evapotranspiration, water storage in soil and groundwater, and catchment discharge) propagating through the Shale Hills Catchments and representative soil series, the filtering effects of the catchment and soil profiles were tested through the wavelet analysis. Typical filtering effects, that is, the characteristic of the role of soil and the groundwater table as a buffer, were observed from the wavelet spectrum, gradually smoothing off the precipitation signal. The hypothesized dual-pore style filtering effects of the soil profile were also confirmed through the coherence spectra and phase differences, rendering them applicable for possible use as “fingerprints” of PF to infer subsurface flow features. We found that PF dominates the catchment's discharge response at the scales from 3 to 12 days, which contributes to the catchment discharge mainly as subsurface lateral flow at upper or middle soil horizons. Through subsurface PF pathways, even the hilltop is likely hydrologically connected to the valley floor, building connections with or making contributions to the catchment discharge. This study highlights the potential of wavelet analysis for retrieving and characterizing subsurface flow processes based on the revealed dual-pore filtering effects of the soil system. Although some limitations and uncertainties still exist, we believe that wavelet methods provide a highly potential but underexplored approach to studying subsurface hydrology.

ACS Style

Hu Liu; Yang Yu; Wenzhi Zhao; Li Guo; Jintao Liu; Qiyue Yang. Inferring Subsurface Preferential Flow Features From a Wavelet Analysis of Hydrological Signals in the Shale Hills Catchment. Water Resources Research 2020, 56, 1 .

AMA Style

Hu Liu, Yang Yu, Wenzhi Zhao, Li Guo, Jintao Liu, Qiyue Yang. Inferring Subsurface Preferential Flow Features From a Wavelet Analysis of Hydrological Signals in the Shale Hills Catchment. Water Resources Research. 2020; 56 (11):1.

Chicago/Turabian Style

Hu Liu; Yang Yu; Wenzhi Zhao; Li Guo; Jintao Liu; Qiyue Yang. 2020. "Inferring Subsurface Preferential Flow Features From a Wavelet Analysis of Hydrological Signals in the Shale Hills Catchment." Water Resources Research 56, no. 11: 1.

Research article
Published: 25 May 2020 in Hydrological Processes
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Riparian plants can adapt their water uptake strategies based on climatic and hydrological conditions within a river basin. The response of cold‐alpine riparian trees to changes in water availability is poorly understood. The Lhasa River is a representative cold‐alpine river in South Tibet and an under‐studied environment. Therefore, a 96 km section of the lower Lhasa River was selected for a study on the water‐use patterns of riparian plants. Plant water, soil water, groundwater, and river water were measured at three sites for δ18O and δ2H values during the warm‐wet and cold‐dry periods in 2018. Soil profiles differed in isotope values between seasons and with the distance along the river. During the cold‐dry period, the upper parts of the soil profiles were significantly affected by evaporation. During the warm‐wet period, the soil profile was influenced by precipitation infiltration in the upper reaches of the study area and by various water sources in the lower reaches. Calculations using the IsoSource model indicated that the mature salix and birch trees (Salix cheilophila Schneid. and Betula platyphylla Suk. ) accessed water from multiple sources during the cold‐dry period, whereas they sourced more than 70% of their requirement from the upper 60–80 cm of the soil profile during the warm‐wet period. The model indicated that the immature rose willow tree (Tamarix ramosissima Ledeb ) accessed 66% of its water from the surface soil during the cold‐dry period, but used the deeper layers during the warm‐wet period. The plant type was not the dominant factor driving water uptake patterns in mature plants. Our findings can contribute to strategies for the sustainable development of cold‐alpine riparian ecosystems. It is recommended that reducing plantation density and collocating plants with different rooting depths would be conducive to optimal plant growth in this environment. This article is protected by copyright. All rights reserved.

ACS Style

Wenbo Rao; Xi Chen; Karina T. Meredith; Hongbing Tan; Man Gao; Jintao Liu. Water uptake of riparian plants in the lower Lhasa River Basin, South Tibetan Plateau using stable water isotopes. Hydrological Processes 2020, 34, 3492 -3505.

AMA Style

Wenbo Rao, Xi Chen, Karina T. Meredith, Hongbing Tan, Man Gao, Jintao Liu. Water uptake of riparian plants in the lower Lhasa River Basin, South Tibetan Plateau using stable water isotopes. Hydrological Processes. 2020; 34 (16):3492-3505.

Chicago/Turabian Style

Wenbo Rao; Xi Chen; Karina T. Meredith; Hongbing Tan; Man Gao; Jintao Liu. 2020. "Water uptake of riparian plants in the lower Lhasa River Basin, South Tibetan Plateau using stable water isotopes." Hydrological Processes 34, no. 16: 3492-3505.

Journal article
Published: 04 May 2020 in Journal of Hydrology
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Flow connectivity in the hillslope–riparian–stream (HRS) system describes the hydrological linkage between upland water and the channel network. However, the time and form of the establishment of HRS connectivity are not adequately understood. Herein, we examined how hillslope structure (topography and soil) and rainfall influence HRS connectivity in a steep, forested, zero-order catchment at the Hemuqiao Hydrological Experimental Station in Southeast China, from July 2016 to November 2017. To this end, surface and subsurface flow, soil moisture, and soil hydraulic conductivity (Ks) were observed, and soil dye staining experiments were conducted. Two patterns of HRS connectivity, namely saturation connectivity that initiates at the soil–bedrock interface (SCSB) and saturation connectivity at different soil horizons (SCSH), were identified. The persistence time of SCSH connectivity was short (<1 h), and the contribution of the perched interflow in different soil horizons to the total runoff was relatively small (0.6–3.0%). Instead, we found that the soil–bedrock interface acted as an important impeding layer that established HRS connectivity. That is, among the rainfall events during which HRS connectivity was established, 90% were established through SCSB connectivity and only 10% were established through SCSH connectivity. We further evaluated the time required to established HRS connectivity and found that SCSB connectivity required more time (4.6–67.4 h) than SCSH connectivity (<1 h). We further found that rainfall intensity determined the initiation of connectivity and that the time required for HRS connectivity decreased exponentially with increasing rainfall intensity (R2 = 0.67). Finally, we found that subsurface saturation excess flow, rather than Hortonian overland flow, was the main contributor to the flood peak during large events. In these events, the total volume of the runoff and flood peak were five and eight times higher than that of subsurface outflow, respectively. These results provide a clearer understanding of runoff generation and can narrow the gap between experiments and models for further development of hydrological theories and methods.

ACS Style

Xiaole Han; Jintao Liu; Puneet Srivastava; Subhasis Mitra; Ruimin He. Effects of critical zone structure on patterns of flow connectivity induced by rainstorms in a steep forested catchment. Journal of Hydrology 2020, 587, 125032 .

AMA Style

Xiaole Han, Jintao Liu, Puneet Srivastava, Subhasis Mitra, Ruimin He. Effects of critical zone structure on patterns of flow connectivity induced by rainstorms in a steep forested catchment. Journal of Hydrology. 2020; 587 ():125032.

Chicago/Turabian Style

Xiaole Han; Jintao Liu; Puneet Srivastava; Subhasis Mitra; Ruimin He. 2020. "Effects of critical zone structure on patterns of flow connectivity induced by rainstorms in a steep forested catchment." Journal of Hydrology 587, no. : 125032.

Journal article
Published: 08 April 2020 in Water Resources Research
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A new eight‐direction algorithm (iFAD8) for the simulation of drainage directions on grid digital elevation models (DEMs) is presented. In this algorithm, a flexible triangular facet construction technique (ND∞) is developed to provide local drainage directions ranging continuously from 0° to 360°. Subsequently, a flow aggregation technique using global deviations of local drainage directions is proposed to simplify the flow paths into a nondispersive format. Another algorithm (FAD8) accompanying the iFAD8 is also presented, which uses the D∞ directions as the local drainage directions. Then FAD8, iFAD8 as well as three existing algorithms are compared on ten abstract terrains including nine basic terrains and a Himmelblau terrain. The algorithms are tested to reproduce exact slope lines and specific catchment areas derived from the terrain functions. The results show that iFAD8 has better performance than FAD8. Both iFAD8 and FAD8 outperform existing algorithms in most cases. The flow aggregation technique is shown to be an excellent choice for nondispersive drainage direction simulation based on infinite directions. The ND∞ direction based on flexible triangular facets is also an improvement to the local infinite direction of D∞. We conclude that the iFAD8 algorithm can provide better definitions of drainage directions. Plain‐language Summary Overland movement of water and soil plays an important role in hydrological cycle and geomorphologic evolution. Analysis and modeling of these processes rely on drainage direction information. Through digitalizing and discretizing a continuous terrain into a mass of grid cells, drainage direction can be assigned to each cell. The accuracy of drainage directions may have a tremendous impact on the hydrologic and geomorphologic modeling. So an advanced algorithm for determination of drainage direction is required. Many algorithms have been proposed for this purpose. But there are some shortcomings in the existing algorithms. Here we present a new algorithm named iFAD8 to provide single drainage direction for each topographic cell. Two newly‐developed techniques are adopted in iFAD8 to improve both local drainage directions and global flow paths. iFAD8 partly optimizes the shortcomings of existing algorithms in theory, and has a better performance on various terrains. Finally, iFAD8 will benefit hydrologic and geomorphologic modeling.

ACS Style

Pengfei Wu; Jintao Liu; Xiaole Han; Zhongmin Liang; Yangyang Liu; Junyuan Fei. Nondispersive Drainage Direction Simulation Based on Flexible Triangular Facets. Water Resources Research 2020, 56, 1 .

AMA Style

Pengfei Wu, Jintao Liu, Xiaole Han, Zhongmin Liang, Yangyang Liu, Junyuan Fei. Nondispersive Drainage Direction Simulation Based on Flexible Triangular Facets. Water Resources Research. 2020; 56 (4):1.

Chicago/Turabian Style

Pengfei Wu; Jintao Liu; Xiaole Han; Zhongmin Liang; Yangyang Liu; Junyuan Fei. 2020. "Nondispersive Drainage Direction Simulation Based on Flexible Triangular Facets." Water Resources Research 56, no. 4: 1.

Preprint content
Published: 23 March 2020
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Characterizing soil volumetric water content (VWC) dynamics at different soil depth plays a key role in hydrological modeling and is essential for effective catchment management. However, our understanding of how critical zone structure (topography and soil) and rainfall affect VWC dynamics is limited. Therefore, the objective of this study was to investigate the effects of the hillslope structure and rainfall on VWC dynamics in a steep forested, zero-order catchment. VWC was measured from soil surface to soil-bedrock interface at five soil layers (0-8, 8-40, 40-70, 70-110, and 110-160 cm) for a complete water year, and covering various landscapes such as an ephemeral stream, riparian, and different hillslope positions. A total of 13 environmental indices, including eight DEM-derived terrain attributes and five soil attributes, were used to investigate the relationships between soil-terrain attributes and VWC. An all-possible-subsets regression model was adopted to construct the soil water content prediction model (SWPM). A geophysical method (ground penetrating radar, GPR) was used to investigate the soil depth to assist in the establishment of SWPM. The results demonstrate that the all-possible-subsets regression model performed well for predicting VWC. Additionally, the strength of the relationships between soil-terrain attributes and VWC could be different through time. For instance, the relationships between the topographic wetness index (TWI) and VWC were all significant (P<0.05) from August to October, whereas the correlation between TWI and VWC was not significant (P≥0.05) at approximately 25% of measurement days from November to February. The results also show that the high correlation between terrain-related attributes and VWC usually occurs in the measurement days with high catchment storage state, whereas the high correlation between soil-related attributes and VWC more often occurs in the measurement days with low catchment storage state. Therefore, the control factors of VWC spatial organization vary from humid (controlled by topographic redistribution of water) to arid (controlled by vertical processes such as evapotranspiration) seasons.

ACS Style

Xiaole Han; Jintao Liu. Seasonal controls of soil water content spatial pattern in a steep forested catchment: A modeling approach. 2020, 1 .

AMA Style

Xiaole Han, Jintao Liu. Seasonal controls of soil water content spatial pattern in a steep forested catchment: A modeling approach. . 2020; ():1.

Chicago/Turabian Style

Xiaole Han; Jintao Liu. 2020. "Seasonal controls of soil water content spatial pattern in a steep forested catchment: A modeling approach." , no. : 1.

Preprint content
Published: 23 March 2020
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An accurate assessment of soil water balance components (SWBCs) is necessary for improving irrigation strategies in any water-limited environment. However, quantitative information of SWBCs is usually challenging to obtain, because none of the components (i.e., irrigation, drainage, and evapotranspiration) can be easily measured under actual conditions. Soil moisture is a variable that integrates the water balance components of land surface hydrology, and the evolution of soil moisture is assumed to contain the memory of antecedent hydrologic fluxes, and thus can be used to determine SWBCs from a hydrologic balance. A database of soil moisture measurements from six experimental plots with different treatments in the middle Heihe River Basin of China was used to test the potential of a soil moisture database in estimating the SWBCs. We first compared the hydrophysical properties of the soils in these plots, such as vertical saturated hydraulic conductivity (Ks) and soil water retention features, for supporting the SWBC estimations. Then we determined evapotranspiration and other SWBCs through a method that combined the soil water balance method and the inverse Richards equation (a model of unsaturated soil water flow based on the Richards equation). To test the accuracy of our estimation, we used both indirect methods (such as power consumption of the pumping irrigation well, and published SWBCs values at nearby sites), and the water balance equation technique to verify the estimated SWBCs values, all of which showed a good reliability of our estimation method. Finally, the uncertainties of the proposed methods were analyzed to evaluate the systematic error of the SWBC estimation and any restrictions on its application. The results showed significant variances among the film-mulched plots in both the cumulative irrigation volumes (652.1~ 867.3 mm) and deep drainages (170.7~364.7 mm). Moreover, the unmulched plot had remarkably higher values in both cumulative irrigation volumes (1186.5 mm) and deep drainages (651.8 mm) compared with the mulched plots. Obvious correlation existed between the volume of irrigation and that of drained water. However, the ET demands for all the plots behaved pretty much the same, with the cumulative ET values ranging between 489.1 and 561.9 mm for the different treatments in 2016, suggesting that the superfluous irrigation amounts had limited influence on the accumulated ET throughout the growing season because of the poor water-holding capacity of the sandy soil. This work confirmed that relatively reasonable estimations of the SWBCs in coarse-textured sandy soils can be derived by using soil moisture measurements; the proposed methods provided a reliable solution over the entire growing season and showed a great potential for identifying appropriate irrigation amounts and frequencies, and thus a move toward sustainable water resources management, even under traditional surface irrigation conditions.

ACS Style

Hu Liu; Yang Yu; Zhongkai Li; Wenzhi Zhao; Qiyue Yang; Rong Yang; Jintao Liu. Estimation of Soil Water Balance Components Based on Continuous Soil Moisture Measurement and Inversed Richards Method in an Irrigated Agricultural Field of a Desert Oasis. 2020, 1 .

AMA Style

Hu Liu, Yang Yu, Zhongkai Li, Wenzhi Zhao, Qiyue Yang, Rong Yang, Jintao Liu. Estimation of Soil Water Balance Components Based on Continuous Soil Moisture Measurement and Inversed Richards Method in an Irrigated Agricultural Field of a Desert Oasis. . 2020; ():1.

Chicago/Turabian Style

Hu Liu; Yang Yu; Zhongkai Li; Wenzhi Zhao; Qiyue Yang; Rong Yang; Jintao Liu. 2020. "Estimation of Soil Water Balance Components Based on Continuous Soil Moisture Measurement and Inversed Richards Method in an Irrigated Agricultural Field of a Desert Oasis." , no. : 1.

Journal article
Published: 11 March 2020 in Hydrology and Earth System Sciences
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Climate warming is changing streamflow regimes and groundwater storage in cold alpine regions. In this study, the Yangbajain headwater catchment in the Lhasa River basin is adopted as the study area to assess streamflow changes and active groundwater storage in response to climate warming. The results show that both annual streamflow and the mean air temperature increase significantly at respective rates of about 12.30 mm per decade and 0.28 ∘C per decade from 1979 to 2013 in the study area. The results of gray relational analysis indicate that the air temperature acts as a primary factor for the increased streamflow. Due to climate warming, the total glacier volume has retreated by over 25 % during the past 50 years, and the areal extent of permafrost has degraded by 15.3 % over the last 20 years. Parallel comparisons with other subbasins in the Lhasa River basin indirectly reveal that the increased streamflow at the Yangbajain Station is mainly fed by the accelerated glacier retreat. Using baseflow recession analysis, we also find that the estimated groundwater storage that is comparable with the GRACE data increases significantly at rates of about 19.32 mm per decade during the abovementioned period. That is to say, as permafrost thaws, more spaces have been made available to accommodate the increasing meltwater. Finally, a large water imbalance (of more than 5.79×107 m3 a−1) between the melt-derived runoff and the actual increase in runoff as well as the groundwater storage is also observed. The results from this study suggest that the impacts of glacial retreat and permafrost degradation show compound behaviors on the storage–discharge mechanism due to climate warming, and that this fundamentally affects the water supply and the mechanisms of streamflow generation and change.

ACS Style

Lu Lin; Man Gao; Jintao Liu; Jiarong Wang; Shuhong Wang; Xi Chen; Hu Liu. Understanding the effects of climate warming on streamflow and active groundwater storage in an alpine catchment: the upper Lhasa River. Hydrology and Earth System Sciences 2020, 24, 1145 -1157.

AMA Style

Lu Lin, Man Gao, Jintao Liu, Jiarong Wang, Shuhong Wang, Xi Chen, Hu Liu. Understanding the effects of climate warming on streamflow and active groundwater storage in an alpine catchment: the upper Lhasa River. Hydrology and Earth System Sciences. 2020; 24 (3):1145-1157.

Chicago/Turabian Style

Lu Lin; Man Gao; Jintao Liu; Jiarong Wang; Shuhong Wang; Xi Chen; Hu Liu. 2020. "Understanding the effects of climate warming on streamflow and active groundwater storage in an alpine catchment: the upper Lhasa River." Hydrology and Earth System Sciences 24, no. 3: 1145-1157.

Journal article
Published: 04 February 2020 in Journal of Hydrology
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Water storage in the Tibetan Plateau (TP) is extremely sensitive to climate change. Observations in TP have revealed warming and moistening trends before 2004 and weakening of those trends after 2004. These changes in the course of climate warming altered hydrological components in TP from the early years of 1992–2003 to the recent decade of 2004–2015, resulting in strong changes of the terrestrial water storage (TWS) in TP. In this study, hydrological and climatic data that determine the budget of TWS in TP were compiled from multiple data sources for 1992–2015. An empirical formula was developed by correlation analysis of TWS from these data with TWS derived from GRACE data for 2003–2015 in TP. The estimated TWS by the formula highly agrees with GRACE data in describing TWS variations across TP, even though it underestimates the absolute value of annual TWS in north TP. The formula was used to estimate TWS variations in 1992–2003, which were compared to those in 2004–2015. Major results show that (1) in the warm and wet region of south TP, the recently reduced rate of climate warming and moistening reversed the trend of annual TWS from increase in 1992–2003 to significant decrease in 2004–2015. This change is largely caused by decreases of soil water and groundwater storage and increased runoff. (2) In the cold and dry region of north TP, the increase of TWS in 1992–2003 accelerated in 2004–2015 because of increases of soil moisture and lake storage. (3) The difference of TWS change in the north and south TP altered the multi-year balance of water storage over the entire TP. Decreasing TWS from 2004 to 2015 lowered multi-year mean TWS in south TP, while increasing TWS in north TP raised its multi-year mean TWS. The reduction of TWS in south TP, with decrease of streamflow and groundwater storage, could threaten the sustainability of surface and subsurface water resources for this critical source region of Asia’s large rivers. The accumulation of TWS following the rise of surface water in north TP could increase spilling of lakes and thus risks of floods and debris flows.

ACS Style

Jiarong Wang; Xi Chen; Qi Hu; Jintao Liu. Responses of terrestrial water storage to climate variation in the Tibetan Plateau. Journal of Hydrology 2020, 584, 124652 .

AMA Style

Jiarong Wang, Xi Chen, Qi Hu, Jintao Liu. Responses of terrestrial water storage to climate variation in the Tibetan Plateau. Journal of Hydrology. 2020; 584 ():124652.

Chicago/Turabian Style

Jiarong Wang; Xi Chen; Qi Hu; Jintao Liu. 2020. "Responses of terrestrial water storage to climate variation in the Tibetan Plateau." Journal of Hydrology 584, no. : 124652.

Journal article
Published: 30 November 2019 in Science of The Total Environment
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The exploitation of groundwater resources is of great importance and has become crucial in the last few decades, especially in arid regions, where surface water resources are scarce and unreliable. The Hexi Corridor (HC) is one of the most agriculturally rich and densely populated areas of arid northwestern China. Increasing demand for water, due to rapid population growth, oasis expansion and urbanization, has increased groundwater use, resulting in wide-scale depletion in this region. Sustainable management of aquifers in the HC requires accurate estimates of the current situation of groundwater resource sustainability. In this work, groundwater storage anomaly (∆GWS) were estimated using the Gravity Recovery and Climate Experiment (GRACE) satellite data, the Global Land Data Assimilation System (GLDAS) data and the water-table fluctuation (WTF) method based on in-situ groundwater level data. Combined with the groundwater sustainability index (SIGWS), groundwater sustainability in the HC was then evaluated. Potential factors that could affect regional groundwater sustainability were analyzed by including and testing climate and socio-economic variables during the period of 1981 to 2016. We found that (1) groundwater in the HC has experienced a general deterioration (except for a sudden and sharp increase observed around 2002) in both storage and sustainability, from ∆GWS = 16.79 cm/year and SIGWS = 0.46 (1985–1990) to ∆GWS = −28.96 cm/year and SIGWS = 0.008 (2007–2016); (2) the lowest value of groundwater sustainability in the HC appeared in the central and eastern regions (SIGWS = 0); (3) human activity was confirmed to be the dominant factor driving the processes of deterioration in groundwater sustainability in the HC, and during the research period, it is striking that relatively limited “positive” effects of the water management project were detected on the regional groundwater resource; this result indicates that damaged groundwater sustainability cannot be easily reversed unless a long-term management policy is implemented. This study also proves that GRACE gravity satellite data has great application potential in groundwater sustainability evaluation in arid regions, especially in developing countries where in-situ data are scarce, and highlights the importance of joint management of surface water and groundwater, in groundwater sustainability management.

ACS Style

Sijia Wang; Hu Liu; Yang Yu; Wenzhi Zhao; Qiyue Yang; Jintao Liu. Evaluation of groundwater sustainability in the arid Hexi Corridor of Northwestern China, using GRACE, GLDAS and measured groundwater data products. Science of The Total Environment 2019, 705, 135829 .

AMA Style

Sijia Wang, Hu Liu, Yang Yu, Wenzhi Zhao, Qiyue Yang, Jintao Liu. Evaluation of groundwater sustainability in the arid Hexi Corridor of Northwestern China, using GRACE, GLDAS and measured groundwater data products. Science of The Total Environment. 2019; 705 ():135829.

Chicago/Turabian Style

Sijia Wang; Hu Liu; Yang Yu; Wenzhi Zhao; Qiyue Yang; Jintao Liu. 2019. "Evaluation of groundwater sustainability in the arid Hexi Corridor of Northwestern China, using GRACE, GLDAS and measured groundwater data products." Science of The Total Environment 705, no. : 135829.

Journal article
Published: 18 November 2019 in Hydrology and Earth System Sciences
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An accurate assessment of soil water balance components (SWBCs) is necessary for improving irrigation strategies in any water-limited environment. However, quantitative information on SWBCs is usually challenging to obtain, because none of the components (i.e., irrigation, drainage, and evapotranspiration) can be easily measured under actual conditions. Soil moisture is a variable that integrates the water balance components of land surface hydrology, and the evolution of soil moisture is assumed to contain the memory of antecedent hydrologic fluxes, and can thus be used to determine SWBCs from a hydrologic balance. A database of soil moisture measurements from six experimental plots with different treatments in the middle Heihe River basin of China was used to test the potential of a such a database for estimating SWBCs. We first compared the hydrophysical properties of the soils in these plots, such as vertical saturated hydraulic conductivity (Ks) and soil water retention features, for supporting SWBC estimations. We then determined evapotranspiration and other SWBCs using a method that combined the soil water balance method and the inverse Richards equation (a model of unsaturated soil water flow based on the Richards equation). To test the accuracy of our estimation, we used both indirect methods (such as power consumption of the pumping irrigation well and published SWBCs values at nearby sites) and the water balance equation technique to verify the estimated SWBCs values, all of which showed good reliability with respect to our estimation method. Finally, the uncertainties of the proposed methods were analyzed to evaluate the systematic error of the SWBC estimation and any restrictions regarding its application. The results showed significant variances among the film-mulched plots in both the cumulative irrigation volumes (652.1–867.3 mm) and deep drainages (170.7–364.7 mm). Moreover, the un-mulched plot had remarkably higher values in both cumulative irrigation volumes (1186.5 mm) and deep drainages (651.8 mm) compared with the mulched plots. Obvious correlation existed between the volume of irrigation and that of drained water. However, the ET demands for all of the plots behaved pretty much the same, with the cumulative ET values ranging between 489.1 and 561.9 mm for the different treatments in 2016, suggesting that the superfluous irrigation amounts had limited influence on the accumulated ET throughout the growing season due to the poor water-holding capacity of the sandy soil. This work confirmed that relatively reasonable estimations of the SWBCs in coarse-textured sandy soils can be derived by using soil moisture measurements; the proposed methods provided a reliable solution over the entire growing season and showed a great potential for identifying appropriate irrigation amounts and frequencies, and thus a move toward sustainable water resources management, even under traditional surface irrigation conditions.

ACS Style

Zhongkai Li; Hu Liu; Wenzhi Zhao; Qiyue Yang; Rong Yang; Jintao Liu. Quantification of soil water balance components based on continuous soil moisture measurement and the Richards equation in an irrigated agricultural field of a desert oasis. Hydrology and Earth System Sciences 2019, 23, 4685 -4706.

AMA Style

Zhongkai Li, Hu Liu, Wenzhi Zhao, Qiyue Yang, Rong Yang, Jintao Liu. Quantification of soil water balance components based on continuous soil moisture measurement and the Richards equation in an irrigated agricultural field of a desert oasis. Hydrology and Earth System Sciences. 2019; 23 (11):4685-4706.

Chicago/Turabian Style

Zhongkai Li; Hu Liu; Wenzhi Zhao; Qiyue Yang; Rong Yang; Jintao Liu. 2019. "Quantification of soil water balance components based on continuous soil moisture measurement and the Richards equation in an irrigated agricultural field of a desert oasis." Hydrology and Earth System Sciences 23, no. 11: 4685-4706.

Preprint content
Published: 13 September 2019
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Saturated hydraulic conductivity (K), drainable porosity (f), and effective aquifer thickness (D) are essential hydrogeological parameters for hydrologic modelling and predicting. Streamflow recession analysis using analytical solutions of Boussinesq equation can yield estimated values for two of these three hydrogeological parameters when one is known a priori. In this study, we improved the inverse method for parameters estimation by combining the modified Kozeny–Carman equation with analytical solutions of Boussinesq equation to express the three hydrogeological parameters (K, f, and D) in relation to catchment characteristics and recession constants in a sloping aquifer. Here, the three parameters can be estimated simultaneously from streamflow recession analysis. Results of the estimated parameters are compared with the field measurements and the soil-texture based estimations in four small experimental catchments. It shows that our estimated values of these catchment-scale parameters can represent equivalent values in the measured aquifer profiles/sites. In hilly areas, the slope aquifer takes a vital effect on the estimates of K and f. Neglecting the sloping effect can lead to overestimation of K and underestimation of f in 1 ~ 2 orders of magnitude in the study catchments. However, even in the hilly catchments, the estimated aquifer thickness D is much greater than that from measurements on hillslopes while it approaches riparian thickness, indicating that the riparian zone takes a vital role on flow recession and the parameter estimations.

ACS Style

Man Gao; Xi Chen; Jintao Liu. Combining analytical solutions of Boussinesq equation with the modified Kozeny–Carman equation for estimation of catchment-scale hydrogeological parameters. 2019, 2019, 1 -37.

AMA Style

Man Gao, Xi Chen, Jintao Liu. Combining analytical solutions of Boussinesq equation with the modified Kozeny–Carman equation for estimation of catchment-scale hydrogeological parameters. . 2019; 2019 ():1-37.

Chicago/Turabian Style

Man Gao; Xi Chen; Jintao Liu. 2019. "Combining analytical solutions of Boussinesq equation with the modified Kozeny–Carman equation for estimation of catchment-scale hydrogeological parameters." 2019, no. : 1-37.

Preprint content
Published: 08 September 2019
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ACS Style

Jintao Liu. Understanding the effects of climate warming on streamflow and active groundwater storage in an alpine catchment, upper Lhasa River. 2019, 1 .

AMA Style

Jintao Liu. Understanding the effects of climate warming on streamflow and active groundwater storage in an alpine catchment, upper Lhasa River. . 2019; ():1.

Chicago/Turabian Style

Jintao Liu. 2019. "Understanding the effects of climate warming on streamflow and active groundwater storage in an alpine catchment, upper Lhasa River." , no. : 1.