Tailan River Basin Research Articles

Chemical Characteristics-Based Evolution of Groundwater in Tailan River Basin, Xinjiang, China

Groundwater plays an important role in ecological environment protection in arid and semi-arid areas. Therefore, understanding the characteristics of hydrochemical evolution is of great significance for the sustainable use of groundwater in the area of the Tailan River Basin. The Tailan River Basin is located in an arid, ecologically sensitive area in western China. In this study, we collected 42 groups of representative water samples from the Tailan River Basin and analyzed the chemical distribution in the groundwater using mathematical statistics, Piper and Gibbs diagrams, ion ratio analysis, and hydrogeochemical simulation methods. We also discussed the water–rock interactions in the groundwater hydrochemical evolutionary process. The results were as follows: (1) The chemical types of groundwater changed from HCO3·SO4-Ca·Na to SO4·Cl-Na·Ca, Cl·SO4-Na, and Cl-Na, and the total dissolved solids content increased from less than 1 g/L to more than 40 g/L from the gravel plain to the fine soil plain. (2) The Gibbs diagram, the ion ratio analysis, and the saturation index showed that the groundwater chemical characteristics in the study area were mainly controlled by water–rock interactions, as well as evaporation and concentration. Along the runoff of groundwater, halite and gypsum were dissolved. Nevertheless, dolomite and calcite precipitated. The relationship between the chlor-alkali index and [(Na+ + K+)-Cl−] and [(Ca2+ + Mg2+)-(HCO3− + SO42−)] indicated that cation exchange also affects the chemical composition of groundwater in the area. (3) Through reverse hydrogeochemical simulation, the main water–rock effect of the groundwater runoff process revealed by qualitative analysis was quantitatively verified.

The Influence of Glacier Mass Balance on River Runoff in the Typical Alpine Basin

Quantifying the effects of alpine GMB (Glacier Mass Balance) on river runoff is an important content of climate change. Uncertainty exists in GMB monitoring when applying remote-sensing technology. There are several reasons for these uncertainties, such as terrain deviation co-registration among different topographic data, the mismatch between GSE (Glacier Surface Elevation) from satellite monitoring and the GMB that comprises the physical glacier properties, the driving factors of GMB, and the response patterns of the runoff within the basin. This paper proposed a method based on the ridge line co-registration of DEMs (Digital Elevation Models), and the Tailan River basin, which is a typical glacier melt runoff recharge basin located in the southern Tianshan Mountains, was selected. Abnormal values in GSE changes were removed using ice thickness data, and the GSE results were optimized based on the regularity of the GSE change with altitude to estimate the GMB. The driving factors of the GMB and the response characteristics of the runoff in the basin were also explored. The results showed that the accuracy of the optimized GSE results across different periods has improved by more than 25%. The mean annual thinning value of GSE in the basin from 2000 to 2022 was −0.25 ± 0.02 m·a−1, corresponding to a GMB value of −0.30 ± 0.02 m w.e.a−1, indicating a consistent GMB loss state. Combined with climate data, the glaciers in the basin were impacted by rising temperatures, and the smallest increase in annual precipitation in the basin was insufficient to compensate for the GMB loss. Moreover, in the past 22 years, glacier meltwater accounts for 46.15% of the total runoff in the Tailan River basin.

基于砂槽试验的开采和人工补给条件下潜水含水层地下水流路径模拟

Understanding the impacts of managed abstraction and recharge, i.e. artificial regulation of groundwater, on flow dynamics contributes to water resources planning and effective management of river basins. Based on the hydrogeological conditions of the aquifer in the Tailan River Basin, northwestern China, a two-dimensional sand-tank physical model and the corresponding numerical model were conceptualized and developed to investigate the influence of such regulation on the moisture content, groundwater flow patterns, groundwater age, residence time distributions, and groundwater flow paths in the groundwater reservoir. Four scenarios were examined at laboratory scale. The results showed that groundwater flow was influenced significantly by artificial regulation and that the depth of influence greatly increased depending on the regulation modes. Abstraction mainly alters the groundwater flow paths and moisture content at the ground surface in the core area of the depression cone and reduces the groundwater age in the entire aquifer. Groundwater flow lines are gradually parted by artificial recharge at different depths. Groundwaters of different ages have different behavior under the different artificial recharge depths and artificial recharge modes. Saddle points (kind of stagnation points) appeared at different locations, which were highly dependent on the modes of artificial regulation. Some of the lessons learned, and some management strategies, are proposed based on the results. Despite the dimensionality and scale of the model adopted, resulting in a relatively very large capillarity zone unrepresentative of field conditions, these findings nonetheless have important implications for understanding groundwater flow dynamics impacted by highly intensive human activities.

Diagnostic calibration of a hydrological model in a mountain area by hydrograph partitioning

Abstract. Hydrological modeling can exploit informative signatures extracted from long time sequences of observed streamflow for parameter calibration and model diagnosis. In this study we explore the diagnostic potential of hydrograph partitioning for model calibration in mountain areas, where meltwater from snow and glaciers is an important source for river runoff (in addition to rainwater). We propose an index-based method to partition the hydrograph according to dominant runoff water sources, and a diagnostic approach to calibrate a mountain hydrological model. First, by accounting for the seasonal variability of precipitation and the altitudinal variability of temperature and snow/glacier coverage, we develop a set of indices to indicate the daily status of runoff generation from each type of water source (i.e., glacier meltwater, snow meltwater, rainwater, and groundwater). Second, these indices are used to partition a hydrograph into four parts associated with four different combinations of dominant water sources (i.e., groundwater, groundwater + snow meltwater, groundwater + snow meltwater + glacier meltwater, and groundwater + snow meltwater + glacier meltwater + rainwater). Third, the hydrological model parameters are grouped by the associated runoff sources, and each group is calibrated to match the corresponding hydrograph partition in a stepwise and iterative manner. Similar to use of the regime curve to diagnose seasonality of streamflow, the hydrograph partitioning curve based on a dominant runoff water source (more briefly called the partitioning curve, not necessarily continuous) can serve as a diagnostic signature that helps relate model performance to model components. The proposed methods are demonstrated via application of a semi-distributed hydrological model (THREW, Tsinghua Representative Elementary Watershed) to the Tailan River basin (TRB) (1324 km2) in the Tianshan Mountains of China. Results show that the proposed calibration approach performed reasonably well. Cross-validation and comparison to an automatic calibration method indicated its robustness.

Fractal Study of Land Use Change in the Tailan River Basin, Xinjiang, China

Based on the land use data observed over the Tailan River Basin (TRB) during the years 1990, 2000, 2005 and 2008, fractal theory is adopted and applied to expound spatial distribution characteristics and variation law of land use change in the arid inland TRB, Xinjiang, China. The results demonstrate spatial fractal characteristics in all land use types. The analysis indicate that the fractal dimensions of different land use types in the TRB are in the order of waters > industrial, mining and residential areas > farmlands > grasslands > unused lands > woodlands in 1990, and in the order of waters > industrial, mining and residential areas > grasslands > farmlands > woodlands > unused lands in 2000, and in the order of waters > industrial, mining and residential areas > grasslands > woodlands > farmlands >unused lands in 2005, and in the order of waters > industrial, mining and residential areas > grasslands > unused lands > woodlands > farmlands in 2008. The fractal dimension values of land use in the TRB in 1990, 2000, 2005 and 2008 are calculated as 1.5993, 1.5986, 1.6079 and 1.6348 respectively. Fractal dimension of land use in the basin is decreased at first then increased, the spatial structure of land used exhibit complex trend, while the land use types show an increase trend. The stability indexes of spatial structure of land use in the TRB in 1990, 2000, 2005 and 2008 are 0.1720, 0.1563, 0.1435 and 0.1428 respectively. These values suggest that the stability of the spatial structure of land use in the basin is gradually decreased.

Evaluation of Climate Change Impact on Sustainability of Tailan Underground Reservoir in China

In order to ensure availability of water throughout the year in the Tailan River basin of northwestern China, an underground reservoir has been constructed in the basin to augment the groundwater resource and efficiently utilize it. This study investigates the potential impact of future climate change on the reservoir by assessing its influence on sustainability of recharge sources to the reservoir. The methods employed involved using a combined Statistical Downscaling Model (SDSM) and Long Ashton Research Station Weather Generator (LARS-WG) to downscale the climate variations of the basin from a global climate model and applying them through a simple soil water balance to quantify their impact on recharge to the reservoir. The results predict the current mean monthly temperature of the basin to increase by 2.01°C and 2.84°C for the future periods 2040-2069 and 2070-2099, respectively, while the precipitations are to decrease by 25% and 36% over the same periods. Consequently, the water balance analyses project the recharge to the reservoir to decrease by 37% and 49% for the periods 2040-2069 and 2070-2099, respectively. Thus the study provides useful information for sustainable management of the reservoir against potential future climate changes.

Optimal Operation of Underground Reservoir in Tailan River Basin

Tailan river basin is a typical drought river basin in northwest China where construction of underground reservoirs is approved as an effective way to solve the problem of water resource shortage in the river basin. In order to ensure water supply efficiency of the underground reservoirs of the basin, it is necessary to research their recharge and supply patterns and to optimally operate them. This paper has, therefore, investigated different recharge locations and recharge ways through numerical simulation of underground flow in an underground reservoir area of the basin to explore a typical scheduling plan for optimal operation of the reservoir. The results show that it is better to recharge the reservoir using the flood season recharge approach at the centre of the reservoir area to ensure its continuous operation. Following from this recharge process, the use of a three-well pumping scheme is regarded as the best choice for optimal water supply from the reservoir. Also, the study indicates that for the same recharge amount, if the recharge time is closer to the pumping peak, then there is the more obvious effect of underground level recovery; the recovery is much better if the recharge time is more concentrated.

Evaluation of unconfined aquifer parameters from flow to partially penetrating wells in Tailan River basin, China

Effective evaluation, management and abstraction of groundwater resources of any aquifer require accurate and reliable estimates of its hydraulic parameters. This study, therefore, looks at the determination of hydraulic parameters of an unconfined aquifer using both analytical and numerical approaches. A long-duration pumping test data obtained from an unconfined aquifer system within the Tailan River basin in Xinjiang Autonomous Region in the northwest of China is used, in this study, to investigate the best method for estimating the parameters of the aquifer. The pumping test was conducted by pumping from a radial collector well and measuring the response in nine observation wells; all the wells used in the test were partially penetrating. Using two well-known tools, namely AquiferTest and MODFLOW, as an aid for the analytical and numerical approaches, respectively, the parameters of the aquifer were determined and their outputs compared. The estimated horizontal hydraulic conductivity, vertical hydraulic conductivity, and specific yield for the analytical approach are 38.1–50.30 m/day, 3.02–9.05 m/day and 0.204–0.339, respectively, while the corresponding numerical estimates are 20.50–35.24 m/day, 0.10–3.40 m/day, and 0.27–0.31, respectively. Comparing the two, the numerical estimates were found to be more representative of the aquifer in the study area since it simulated the groundwater flow conditions of the pumping test in the aquifer system better than the analytical solution.

Interpretation of Pumping Test with Radial Collector Well Using a Reservoir Model

AbstractThis study proposes a reservoir model for evaluation of aquifer parameters from a long duration pumping test conducted with a radial collector pumping well and nine observation wells in an unconfined aquifer in the Tailan River basin of China. The proposed model, based on the concept of double continuum, was used to conceptualize the pumping test site into conduit and porous reservoirs coupled by a linear flow exchange for simulating flow during the pumping test. The set of model equations developed from the concept were solved by an iterative method. The model-simulated hydraulic heads agree reasonably well with the observation heads in both the pumping and observation wells at an average normalized root mean square error of 10.99 and 8.06%, respectively, during pumping but were weaker in the recovery period. This notwithstanding, the specific yield estimates compare well with the range obtained for a numerical modeling of the entire aquifer basin. Significantly, the model was applied successfull...

Ground Reservoir: A New Pattern of Groundwater Utilization in Arid North-west China -A Case Study in Tailan River Basin

It was used to build high dam as an engineering technical plan for solving the problem of water storage and regulation in the arid inland river system. In this paper, based on the analysis on the experiences in construction of underground reservoirs at home and abroad, the characteristics of geomorphic unit storage structures in arid inland river basins, the geological geomorphic structural condition suitable for construction of underground reservoir were analyzed, the difficult points and solving options for construction and utilization of underground reservoir were discussed as well. In the light of the characteristics of the traditional Karez Canal systems in Xinjiang, the concept of underground reservoir construction which is composed of the Karez wells across a river has been proposed, the research progress and key technical points in the feasibility model test of the case study in Tailan River Basin were discussed in the third part, and it showed that the underground reservoir with Karez wells across a river had better useful prospects in arid inland river basins. Finally, the paper tried to propose a new pattern of unified regulation of surface and ground water which takes the underground reservoir storage regulation as the main measure for water resources development & utilization in river basin, and the new pattern may be a beneficial trial for effective utilization and rational allocation of water resources in arid inland river basin. The underground reservoir and its integrated regulation with surface water would has better applying prospects in central Asia region, and is worthy making further research.

Conjunctive use of surface and groundwater in central Asia area: a case study of the Tailan River Basin

Conjunctive use of surface and groundwater is an effective approach to relief water resources shortages and its uneven temporal and spatial distribution in arid inland regions of central Asia. In this paper, 16 characteristic factors of water resources and related systems which are sensitive to different types of conjunctive use were selected in order to develop an index system for evaluation impact of conjunctive use, based on the fundamental types of water resources conjunctive use in inland basins. In an attempt to address the issue of spring drought and summer floods in Tailan River Basin in Xinjiang, three scenarios of conjunctive use of surface water and groundwater, well-canal combination, piedmont reservoirs and groundwater reservoirs were investigated. The utilization of water resources and the response of its related systems were evaluated and analyzed quantitatively using the groundwater numerical simulation model (Visual MODFLOW). Furthermore, the impacts of conjunctive use were assessed using the method of multi-level fuzzy comprehensive assessment. The results show that the scheme of combination of Laolongkou piedmont reservoir regulation-groundwater development, is the best in terms of the evaluation of water conjunctive use effects, followed by the well-canal combination. The comprehensive effect of well-canal combination along with groundwater reservoir wouldn’t be better than the former both.

Simulation of the relationship between land use and groundwater level in Tailan River basin, Xinjiang, China

Groundwater is widely recognized as the most significant water resource for irrigation and drinking purposes in the extremely-arid inland river region. However, land use is a major force altering the hydrological processes over a range of temporal and spatial scales. Therefore, understanding the interaction between land use and groundwater processes will definitely contribute to formulate a regional sustainable development strategy and recognize the impact of land use on the groundwater flow regime in the Tailan River basin. A numerical simulation of groundwater level for the inland river basin and scenario analysis under land use using FEFLOW is presented. Spatial data of the regional land use were processed using GIS, and the effects of land use on groundwater level were simulated. The amount of irrigation water and pumped groundwater have the most remarkable influences on groundwater level as main source/sink factors. Their variations were simulated according to the irrigation systems with different crops. Other factors including percolation and evapotranspiration of precipitation and condensed water jointly exerted influences on groundwater level. Changes to farmlands had the greatest impact on Tailan River basin for groundwater level, and unused land and Gobi had the least impact on groundwater level. Groundwater level maintained a decreasing trend in the irrigated zone, and increasing groundwater pumping would further intensify the water shortage in Tailan river basin. This coupled effects resulted from land use and extensive groundwater pumping were considered as the major human-induced factors influencing the groundwater system in the extremely-arid inland river basins. The results can provide useful support for land use. Understanding hydrological processes at the watershed level is essential in land use and water resource planning and management, and the proposed approach can be used as a management and planning tool for evaluating the local and overall impacts of land use management on the surface and groundwater flow regimes.