Simulation of surface runoff in theWujiang River watershed based on GIS

Surface runoff in the Wujiang River watershed was simulated by a GIS-based method using precipitation, hydrology data, and land-use data. The volume of surface runoff is chiefly controlled by climates, topographical characteristics and types of land use at the watershed. Five subwatersheds that can represent the whole watershed were chosen and their average annual precipitation, average annual surface runoff and current land use were calculated respectively in the grid model of the Wujiang River watershed based on the climate and hydrology data from 1965 to 2000 and the land-use data acquired in the year of 2000. Surface runoff is assumed to be a function of precipitation and land use and the multiple regression tool is used to determine the relationship between surface runoff, precipitation and present land use. Thus, the rainfall-runoff model for each land-use type has been established. When calibrating these models, the results show that the percent errors are all below 7%, which indicates that the accuracy of this simulation is high.     

Characteristics and influencing factors of runoff changes in the upper Shule River basin from 1954 to 2016北大核心CSCD

River runoff is an important water resource in the arid region of northwest China. Under the back⁃ ground of climate change,the exploration on change characteristics and influencing factors of river runoff is of great significance for understanding the law of river hydrological change. Based on the daily discharge of Chang⁃ mabao hydrological station,the observation materials from meteorological stations and radiosonde stations,and the first and second Chinese glacier inventory,the variation characteristics and possible influencing factors of runoff in the upper Shule River were systematically analyzed by using the linear trend,empirical mode decompo⁃ sition and hierarchical multiple regression. The results show that the annual runoff of the upper Shule River showed a significant increasing trend during 1954-2016,with a rate of 1. 00×108 m3·（10a）-1. Both runoff in flood period and non-flood period also showed a similar increasing trend. The runoff suddenly changed in 1999 and had two oscillation periods of about 15a and 7a,among them the 15a oscillation period was the most signifi⁃ cant. Both cumulative positive temperature and precipitation were the main climatic factors affecting the runoff in the upper Shule River,which can explain more than 80% of the runoff change. There was a significant posi⁃ tive correlation between the summer runoff in the upper Shule River and the height of 0 ℃ layer. It means that the height changes of 0 ℃ layer can be used to predict the runoff change of the river in flood period,which provides an important reference for evaluating the runoff change of glacial melt recharge rivers in the arid re⁃ gion of northwest China. From 1966 to 2006,the ice volume in the upper Shule River basin decreased by about 5. 77 km3,indicating that glacier changes play a crucial role in the change and regulation of runoff in the basin. © Journal of Glaciology and Geocryology 2022.     

Characteristics and causes of changes in annual runoff of the Wuding River in 1956–2009

The Yellow River is the second largest river in China. Its runoff experienced rapid changes in the past decades. The trend and driving forces of change of the river’s runoff has been a hot topic in some academic fields in China in recent years, due to its importance in solving the contradiction between supply and demand of water resources, reasonable exploitation and utilization of water resources and its significance in promoting the social, economic and ecologically sustainable development. The Wuding River is one of the large tributaries in the Middle Yellow River and soil and water conservation measures have been implemented in the tributary much earlier. It can be a good example for investigating the trend and causes of changes of runoff of the Yellow River. In this paper, the variation trend and abrupt change are determined in the time series of annual runoff of the Wuding River recorded at a hydrological station near its outlet during the period from 1956 to 2009 using several time series analysis methods. Secondly, the influences of climate change and human activities are estimated through calculating the amount of runoff reduction due to climate change in different periods. Results show that the annual runoff was continually decreasing, the drought trend was aggravating, and abrupt change in runoff series appeared in 1971 and 1997 as a result of large scale water and soil conservation measure after 1971 and ecosystem restoration program since 1997. It is also found that human activities were the main influence factor for runoff reduction during the period from 1972 to 2009. The contributions from climate change increased from about 23 to 30 %, and those from human activities decreased from 77 to 70 % from the period of 1972–1996 to the period of 1997–2009. Finally, a formula is built to reveal the relation of runoff with both climate factors and each main kind of human activities.     

Assessment of water quality and pollution of the Lake Seyfe basin, Kırşehir, Turkey

Lake Seyfe is located in a closed basin near K?r?ehir in the central Anatolian region, Turkey. The aim of this study is to evaluate the groundwater quality and effects of lithogenic contamination carried out in the Lake Seyfe basin, which is represented by various lithologies and groundwater types. Seyfe, Horla and Akp?nar springs are recharged through marbles at the western and southwestern of the basin are ultimately and discharged into the K?z?l?rmak Formation and Lake Seyfe. The waters of deep wells drilled into the marbles are of bicarbonate type (type I) in the Ca²⁺–Mg²⁺–HCO₃ ^? and Ca²⁺–HCO₃ ^? facies. Özlühüyük spring and waters from most of trenches and shallow wells, which are fed by the K?z?l?rmak Formation, have a mixed (type II) composition in the Ca²⁺–Mg²⁺–HCO₃ ^?–Cl^? facies. Groundwater in the alluvium and K?z?l?rmak Formation along Lake Seyfe has a salty (type III) character in the Na⁺–Cl^? facies. The main reasons of formation and change of the groundwater salinity and hydrochemical facies in the Seyfe basin are causing the various (a) lithogenic pollution and heterogeneity of the K?z?l?rmak Formation, (b) salinity of the upper soil zones, and (c) evaporation of the trench and channel waters open to the atmosphere. Considering parameters such as sodium hazard, specific conductivity, bicarbonate and carbonate hazards, waters in the study area are generally suitable for agricultural usage.     

Identification of landslide susceptibility zones in Gish River basin,West Bengal,India

The occurrence of landslide in the hilly region of Darjeeling during monsoon season is a matter of serious concern. Every year this natural hazard damages the major roads at several places and thus disrupts the transport and communication system in this region. This paper tries to prepare a landslide susceptibility zone (LSZ) map for the Gish River basin. A total number of 16 spatial parameters have been taken for this study and these are categorised under six factor clusters or groups for example, triggering factors, protective factor, lithological factors, morphometric factors, hydrological factors and anthropogenic factors. The LSZ map is prepared by integrating all the parameters adopting the weighting base as logistic regression. The landslide susceptibility map shows that nearly 9.11% of the area falls under the very high landslide-susceptible zone while 40.28% of the area of the total basin lies under the very low landslide-susceptible zone. The landslide-susceptible model is validated through the receiver operating characteristic curve. This curve shows 86% success rate in defining landslide-susceptible zones and 83.40% prediction rate for the occurrence of landslides. The spatial relationship between the landslide susceptibility model and other factors’ groups shows that the morphometric factors’ cluster (mainly slope) is the focalone for the determination of landslide-susceptible zone.     

Streamflow changes and its influencing factors in the mainstream of the Songhua River basin,Northeast China over the past 50 years

The Songhua River plays a key role in the national development of China, owing to its unique natural condition and resources. Recent changes in the streamflow in the Songhua River are important with regard to local sustainable development and management under the background of global warming and aggravating soil erosion. In order to detect changes in the streamflow, two streamflow series from 1955 to 2004 (observed at the Harbin and Jiamusi stations) in the mainstream of Songhua River basin were obtained, and methods of statistical analysis, wavelet transform, and double mass analysis were employed to analyze the data. Reasons for the changes to the streamflow are discussed with respect to natural and man-made drivers. The results show the following: (1) From 1955 to 2004, the streamflow series present obvious declining trends. (2) The streamflow series followed the pattern of a wet–dry–wet–dry cycle pattern over the past 50 years. In the mainstream of Songhua River, wet years mainly occurred during the periods of 1955–1966 and 1984–1993, while dry years mainly occurred in the 1970s and after 2000. (3) Within the 50-year scale, the streamflow series appeared in the main periods of circa 33-, 13- and 4-year, in which the 33-year periodicity is the strongest. (4) Precipitation and temperature directly influenced the streamflow in the mainstream of the basin. The discharge was positively correlated with the precipitation and negatively correlated with the temperature. In addition, human activity was another important driving factor for streamflow change. (5) In the mainstream of Songhua River basin, the influences on streamflow can be divided into three periods: 1955–1976, 1977–1997, and 1998–2004. In the first period climate change played a dominant role, and during the latter two periods human influences were enhanced significantly.     

Multi-method assessment of connectivity between surface water and shallow groundwater: the case of Limarí River basin,north-central Chile

A study that tests the applicability and consistency of independent but complementary approaches in the assessment of interactions between surface water and shallow groundwater within a water-stressed basin is described. The mostly agricultural Limarí basin in arid north-central Chile was chosen as a suitable case study. The analyses involved: (1) a connectivity index method, (2) hydrochemistry, and (3) water isotopic geochemistry. Chemical and isotopic data were obtained from two sampling campaigns conducted in April (fall) and December (summer) of 2011 in 22 sampling locations, which included surface water and groundwater. The results obtained by each of the methodologies were mutually consistent and indicate high connectivity conditions. Additionally, the relative contribution by different sources was assessed through end-member mixing analysis, and for reaches of the river that showed gaining conditions, the contribution of groundwater inflow to stream discharge was estimated. It is suggested that this multi-method approach is useful for the characterization of surface-water–groundwater interactions, since it at least represents a suitable starting point for obtaining basic information on these relationships. Thus, it may become the base for further studies in arid and semi-arid basins facing water management challenges.     

Assessment of variations in water quality using statistical techniques: a case study of Işıklı Lake, Çivril/Denizli,Turkey

A study of the hydrochemical evaluation of waters in the I??kl? Lake and surrounding area was carried out with the objective of identifying the geochemical processes and their relation with water quality in the region. The multivariate statistical techniques were used in the hydrochemical evaluation of waters. Statistical analysis of water quality parameters was made to seeing the interrelationship between different variables in order to explain the water quality and pollution status of study area. For this purpose, water samples were taken from lake, river, stream, and springs which are represented by investigated area and water qualities were evaluated. Generally, Ca²⁺, Mg²⁺, and Cl^?, HCO₃ ^? ions are dominant within surface water and water sources. Arsenic concentration increase is determined in I??kl? spring and Kufi stream water samples. Also, aluminum concentration is high level in the Kufi stream water samples. This increase was related to igneous rocks as geogenic origin. Also, geogenic contamination was identified in R-mode factor and cluster analyses. There is high correlation between electrical conductivity and major ions of waters.     

Assessment of heavy metal contents in bed sediments of a mineralized catchment of the Agno River, Benguet, Philippines

Several former and existing gold and copper mines of the Benguet Province in northern Philippines are situated in the Baloy catchment. Rivers and tributaries drain an area of approximately 89 square kilometers before joining the main Agno River which drai…     

Drought–flood variation and its correlation with runoff in three headstreams of Tarim River, Xinjiang, China

The Tarim River lies in the inland area of Northwest China, which has a semiarid or arid climate. Because of relatively scarce precipitation in this area, the main water resource is runoff from a mountainous drainage basin. It is very important to ascertain variations of regular hydrologic and meteorological time series data. Through the use of monthly precipitation and hydrologic data in the three headstream mountain areas of the Tarim River over the past 50 years, this work analyzes the variation of a drought–flood index and annual runoff volume, along with spatio-temporal structures of the index related to runoff at multiple time scales, via non-parametric testing and a wavelet transform method. Wavelet transform can clearly demonstrate many characteristics of the time series, including trend, shift, and major periods. Based on the analysis, the following conclusions can be drawn: (1) the drought–flood indices showed increasing trends for the Aksu and Yarkand rivers, and rose non-significantly for Hotan River. The indices of the three headstreams changed remarkably (p < 0.05) in 1986. The curves of wavelet variance show that significant periods of the indices are 4 and 8 years for Aksu and Hotan rivers, and 8 and 10 years for Yarkand River; (2) runoff of the Aksu and Hotan rivers had significant periods of 6 and 8 years, plus 3 and 9 years for Hotan River; (3) there was significant correlation between the drought–flood indices and annual runoff volume in the three headstreams. The results provide important information toward achieving predictability of flood and drought in Northwest China.     

Assessment of aquifer vulnerability to contamination in Khanyounis Governorate, Gaza Strip—Palestine, using the DRASTIC model within GIS environment

Groundwater is a very important natural resource in Khanyounis Governorate (the study area) for water supply and development. Historically, the exploitation of aquifers in Khanyounis Governorate has been undertaken without proper concern for environmental impact. In view of the importance of quality groundwater, it might be expected that aquifer protection to prevent groundwater quality deterioration would have received due attention. In the long term, however, protection of groundwater resources is of direct practical importance because, once pollution of groundwater has been allowed to occur, the scale and persistence of such pollution makes restoration technically difficult and costly. In order to maintain basin aquifer as a source of water for the area, it is necessary to find out, whether certain locations in this groundwater basin are susceptible to receive and transmit contamination. This study aims to: (1) assess the vulnerability of the aquifer to contamination in Khanyounis governorate, (2) find out the groundwater vulnerable zones to contamination in the aquifer of the study area, and (3) provide a spatial analysis of the parameters and conditions under which groundwater may become contaminate. To achieve that, DRASTIC model within geographic information system (GIS) environment was applied. The model uses seven environmental parameters: depth of water table, net recharge, aquifer media, soil media, topography, impact of vadose zone, and hydraulic conductivity to evaluate aquifer vulnerability. Based on this model and by using ArcGIS 9.3 software, an attempt was made to create vulnerability maps for the study area. According to the DRASTIC model index, the study has shown that in the western part of the study area the vulnerability to contamination ranges between high and very high due to the relatively shallow water table with moderate to high recharge potential, and permeable soils. To the east of the previous part and in the south-eastern part, vulnerability to contamination is moderate. In the central and the eastern part, vulnerability to contamination is low due to depth of water table. Vulnerability analysis of the DRASTIC Model indicates that the highest risk of contamination of groundwater in the study area originates from the soil media. The impact of vadose zone, depth to water level, and hydraulic conductivity imply moderate risks of contamination, while net recharge, aquifer media, and topography impose a low risk of aquifer contamination. The coefficient of variation indicates that a high contribution to the variation of vulnerability index is made by the topography. Moderate contribution is made by the depth to water level, and net recharge, while impact of vadose zone, hydraulic conductivity, soil media, and Aquifer media are the least variable parameters. The low variability of the parameters implies a smaller contribution to the variation of the vulnerability index across the study area. Moreover, the “effective” weights of the DRASTIC parameters obtained in this study exhibited some deviation from that of the “theoretical” weights. Soil media and the impact of vadose zone were the most effective parameters in the vulnerability assessment because their mean “effective” weights were higher than their respective “theoretical” weights. The depth of water table showed that both “effective” and “theoretical” weights were equal. The rest of the parameters exhibit lower “effective” weights compared with the “theoretical” weights. This explains the importance of soil media and vadose layers in the DRASTIC model. Therefore, it is important to get the accurate and detailed information of these two specific parameters. The GIS technique has provided an efficient environment for analysis and high capabilities of handling large spatial data. Considering these results, DRASTIC model highlights as a useful tool that can be used by national authorities and decision makers especially in the agricultural areas applying chemicals and pesticides which are most likely to contaminate groundwater resources.     

The effects of the July 2005 catastrophic inundations in the Siret River��s Lower Watershed, Romania

The Siret River originates from the Wooded Carpathians (Ukraine) and has a length of 559 km on the Romanian territory. The upper river course is set on the Ukrainian territory, the middle course flows through the Suceava Tableland, and then the limit between the Moldavian Subcarpathians and the Bârlad Tableland, followed by the lower course crosses the Inferior Siret Plain. The hydrographical network includes 1,013 water tributaries (representing the richest river from this point of view in Romania) and has a length of 15,157 km, which represents 19.2% of the total length of the Romanian river network. This materializes in a density of 0.35 km/km², compared to 0.33 km/km² which is the average for Romania. The Siret River has the greatest watershed area, with a total surface of 42,890 km², which represents 18.1% of the Romanian territory. Its discharge is the highest of all internal rivers of Romania, with an average discharge of 210 m³/s at the river mouth, and this is caused by the fact that most of the tributaries come from mountainous sectors, namely the Eastern Carpathians. In the summer of 2005, the most powerful floods ever occurred in the Siret River watershed with significant negative effects on the country??s economy. Considering the multiannual average discharge of 210 m³/s, the maximum discharge recorded on July 16, 2005, was of 4,650 m³/s at Lungoci. The main cause of these events is the deforestation of the small watersheds located in the mountainous sector of the counties of Vrancea, Bacau and Neamt. The total surface affected by floods was of 58,323.936 hectares, of which: 34,142.349 ha (58.54%) arable land, 6,697.486 ha (11.48%) orchards and wine-growing plantations, 1,863.698 ha (3.20%) built areas, 2,866.313 ha (4.91%), forests 4,915.985 ha (8.43%), waters 2,081.047 ha (3.57%), and unproductive land 5,757.058 ha (9.87%). Besides the material losses (over 10,000 houses completely destroyed), 24 human deaths were recorded together with the loss of thousands of domestic animals, whose overall value exceeded two million Euros. The estimation of the extent of the flooding and its impact in the Siret River watershed has been performed using LANDSAT TM 2003 satellite images and the FAO-LCCS classification methodology, in the ASR-CRUTA remote sensing laboratory, with the images offered after activating the International CHARTER (Call ID-98).     

Assessment of nutrient sources and paleoproductivity during the past century in Longgan Lake, middle reaches of Yangtze River, China

A 63-cm sediment core documents that the concentrations of nutrients in sediment, such as organic carbon, nitrogen and phosphorous, continually increased during the last century in Longgan Lake, middle reaches of the Yangtze River, China. C/N ratio and δ^13Corg revealed that organic matter in the sediment derived mainly from aquatic and terrestrial sources is a minor contributor. Excess phosphorous is related to human activities marked by utilization of phosphoric fertilizers since 1952 A.D. The increase of δ^13Corg towards the sediment surface, together with increasing of OC and N accumulation, indicated the elevation of lake primary productivity due to excess phosphorous loading caused by utilization of phosphoric fertilizer. The decrease of δ^15N during the primary productivity elevation process, especially after 1952, can be attributed to the discharged of nitrogen with lower δ^15N into the lake.     

Mapping of fluoride ions in groundwater of Dindigul district, Tamilnadu, India—using GIS technique

The accurate information through water quality analysis, scientific study on F ^? distribution in groundwater and geochemical knowledge with spatial information on geology and climate are necessary to understand the source/cause, type and level of F ^? contamination. The Dindigul district is a hard-rock terrain and marked as one of the fluoride-rich area in Tamilnadu due to occurrence of various rock types including fluoride-bearing minerals. The F ^? content of groundwater can thus originate from the dissolution of fluoride-bearing minerals in the bed rock. Eighty-six representative groundwater samples from Dindigul district was collected during two different seasons. Samples were analysed for F ^?, other major cations and anions. The study area is chiefly composed of hornblende biotite gneiss and charnockite, apart from this untreated tannery effluents also let from many places in the study area. Geographical Information System technique was adopted to study the sources of F ^?, and it was found that F ^? in the study is mainly attributed to geogenic source.     

Combining flux estimation techniques to improve characterization of groundwater–surface-water interaction in the Zenne River,Belgium

The management of urban rivers which drain contaminated groundwater is suffering from high uncertainties regarding reliable quantification of groundwater fluxes. Independent techniques are combined for estimating these fluxes towards the Zenne River, Belgium. Measured hydraulic gradients, temperature gradients in conjunction with a 1D-heat and fluid transport model, direct flux measurement with the finite volume point dilution method (FVPDM), and a numerical groundwater flow model are applied, to estimate vertical and horizontal groundwater fluxes and groundwater–surface-water interaction. Hydraulic gradient analysis, the temperature-based method, and the groundwater flow model yielded average vertical fluxes of –61, –45 and –40 mm/d, respectively. The negative sign indicates upward flow to the river. Changes in exchange fluxes are sensitive to precipitation but the river remained gaining during the examined period. The FVPDM, compared to the groundwater flow model, results in two very high estimates of the horizontal Darcy fluxes (2,600 and 500 mm/d), depending on the depth of application. The obtained results allow an evaluation of the temporal and spatial variability of estimated fluxes, thereby helping to curtail possible consequences of pollution of the Zenne River as final receptor, and contribute to the setup of a suitable remediation plan for the contaminated study site.     

Geochemistry of О, Н, C,S, and Sr isotopes in the water and sediments of the Aral basin

The paper presents original authors' data on the O, H, C, S, and Sr isotopic composition of water and sediments from the basins into which the Aral Sea split after its catastrophic shoaling: Chernyshev Bay (CB), the basin of the Great Aral in the north, Lake Tshchebas (LT), and Minor Sea (MS). The data indicate that the δ¹⁸О, δD, δ¹³C, and δ³⁴S of the water correlate with the mineralization (S) of the basins (as of 2014): for CB, S = 135.6‰, δ¹⁸О = 4.8 ± 0.1‰, δD = 5 ± 2‰, δ¹³C (dissolved inorganic carbon, DIC) = 3.5 ± 0.1‰, δ³⁴S = 14.5‰; for LT, S = 83.8‰, δ¹⁸О = 2.0 ± 0.1‰, δD =–13.5 ± 1.5‰, δ¹³C = 2.0 ± 0.1‰, δ³⁴S = 14.2‰; and for MS, S = 9.2‰, δ¹⁸О =–2.0 ± 0.1‰, δD =–29 ± 1‰, δ¹³C =–0.5 ± 0.5‰, δ³⁴S = 13.1‰. The oxygen and hydrogen isotopic composition of the groundwaters are similar to those in MS and principally different from the artesian waters fed by atmospheric precipitation. The mineralization, δ¹³С, and δ³⁴S of the groundwaters broadly vary, reflecting interaction with the host rocks. The average δ¹³С values of the shell and detrital carbonates sampled at the modern dried off zones of the basins are similar: 0.8 ± 0.8‰ for CB, 0.8 ± 1.4‰ for LT, and –0.4 ± 0.3‰ for MS. The oxygen isotopic composition of the carbonates varies much more broadly, and the average values are as follows: 34.2 ± 0.2‰ for CB, 32.0 ± 2.2‰ for LT, and 28.2 ± 0.9‰ for MS. These values correlate with the δ¹⁸O of the water of the corresponding basins. The carbonate cement of the Late Eocene sandstone of the Chengan Formation, which makes up the wave-cut terrace at CB, has anomalously low δ¹³С up to –38.5‰, suggesting origin near a submarine methane seep. The δ³⁴S of the mirabilite and gypsum (11.0 to 16.6‰) from the bottom sediments and young dried off zone also decrease from CB to MS in response to increasing content of sulfates brought by the Syr-Darya River (δ³⁴S = 9.1 to 9.9‰) and weakening sulfate reduction. The ⁸⁷Sr/⁸⁶Sr ratio in the water and carbonates of the Aral basins do not differ, within the analytical error, and is 0.70914 ± 0.00003 on average. This value indicate that the dominant Sr source of the Aral Sea is Mesozoic–Cenozoic carbonate rocks. The Rb–Sr systems of the silicate component of the bottom silt (which is likely dominated by eolian sediments) of MS and LT plot on the Т = 160 ± 5 Ma, I₀ = 0.7091 ± 0.0001, pseudochron. The Rb–Sr systems of CB are less ordered, and the silt is likely a mixture of eolian and alluvial sediments.     

Hydrochemical characteristics of surface and groundwater and suitability for drinking and agricultural use in the Upper Tigris River Basin,Diyarbakır–Batman,Turkey

Investigations were undertaken into the quality of surface water and groundwater bodies within the Upper Tigris Basin in Turkey to determine their suitability for potable and agricultural use. In the study area, the majority of the groundwater and surface water samples belong to the calcium–magnesium–bicarbonate type (Ca–Mg–HCO₃) or magnesium–calcium–bicarbonate type (Mg–Ca–HCO₃). Chemical analysis of all water samples shows that the mean cation concentrations (in mg/L) were in the order Ca²⁺ > Mg²⁺ > Na⁺ > K⁺ and that of anions are in the order \( \text{HCO}_{3}^{ - } \) > \( \text{SO}_{4}^{2 - } \) > Cl^? > \( \text{CO}_{3}^{ - } \) for all groundwater and surface water samples. The Mg²⁺/Ca²⁺ ratio ranges from 0.21 to 1.30 with most of the values greater than 0.5, indicating that weathering of dolomites is dominant in groundwater. The analysis reveals that all of the samples are neutral to slightly alkaline (pH 7.0–8.7). Groundwater and surface water suitability for drinking usage was evaluated according to the World Health Organization and Turkish Standards (TSE-266) and suggests that most of the samples are suitable for drinking. Various determinants such as sodium absorption ratio, percent sodium (Na %), residual sodium carbonate and soluble sodium percentage revealed that most of the samples are suitable for irrigation. According to MH values, all of the well water samples were suitable for irrigation purposes, but 80 and 81.82% of Zillek springs and surface water samples were unsuitable. As per the PI values, the water samples from the study area are classified as Class I and Class II and are considered to be suitable for irrigation.