Hydrological models are very useful tools for evaluating water resources, and the hydroclimatic hazards associated with the water cycle. However, their calibration and validation require the use of performance criteri...Hydrological models are very useful tools for evaluating water resources, and the hydroclimatic hazards associated with the water cycle. However, their calibration and validation require the use of performance criteria which choice is not straightforward. This paper aims to evaluate the influence of the performance criteria on water balance components and water extremes using two global rainfall-runoff models (HBV and GR4J) over the Ouémé watershed at the Bonou and Savè outlets. Three (3) Efficacy criteria (Nash, coefficient of determination, and KGE) were considered for calibration and validation. The results show that the Nash criterion provides a good assessment of the simulation of the different parts of the hydrograph. KGE is better for simulating peak flows and water balance elements than other efficiency criteria. This study could serve as a basis for the choice of performance criteria in hydrological modelling.展开更多
Accurate estimation of crop evapotranspiration(ETc) and soil water balance, which is vital for optimizing water management strategy in crop production, can be performed by simulation. But existing software has many de...Accurate estimation of crop evapotranspiration(ETc) and soil water balance, which is vital for optimizing water management strategy in crop production, can be performed by simulation. But existing software has many deficiencies, including complex operation, limited scalability, lack of batch processing, and a single ETc model. Here we present simET, an open-source software package written in the R programming language. Many concepts involved in crop ETc simulation are condensed into functions in the package. It includes three widely used crop ETc models built on these functions: the single-crop coefficient,double-crop coefficient, and Shuttleworth–Wallace models, along with tools for preparing model data and comparing estimates. SimET supports ETc simulation in crops with repeated growth cycles such as alfalfa, a perennial forage crop that is cut multiple times annually.展开更多
The aim of this study is to evaluate the hydrological impacts of climate change on the water balance of Lake Tana in Ethiopia. Impact assessments are by downscaled General Circulation Model (GCM) output and hydrologic...The aim of this study is to evaluate the hydrological impacts of climate change on the water balance of Lake Tana in Ethiopia. Impact assessments are by downscaled General Circulation Model (GCM) output and hydrological modeling. For A2 and B2 emission scenarios, precipitation, maximum and minimum temperature estimates from the HadCM3 GCM were used. GCM output was downscaled using the Statistical DownScaling Model (SDSM 4.2). Impact analyses were applied for three future time periods: early, mid and late 21st century. Over-lake evaporation is estimated by Hardgrave’s method, and over-lake precipitation is estimated by inverse distance weighing interpolation, whereas inflows from gauged and ungauged catchments are simulated by the HBV hydrological model. Findings indicate increases in maximum and minimum temperature on annual base for both emission scenarios. The projection of mean annual over lake precipitation for both A2 and B2 emission scenarios shows increasing pattern for 21st century in comparison to the baseline period. The increase of mean annual precipitation for A2 emission scenario is 9% (112 mm/year), 10% (125 mm/year) and 11% (137 mm/year) for the three future periods respectively. B2 emission scenario mean annual precipitation shows increase by 9% (111 mm/year), 10% (122 mm/year) and 10% (130 mm/year) respectively for the three future periods. Findings indicate consistent increases of lake storage for all three future periods for both A2 and B2 emission scenarios.展开更多
Observation and modeling of the coupled energy and water balance is the key to understand hydrospheric and cryospheric processes at high elevation.The paper summarizes the progress to address this aspect in relation w...Observation and modeling of the coupled energy and water balance is the key to understand hydrospheric and cryospheric processes at high elevation.The paper summarizes the progress to address this aspect in relation with different earth system elements,from glaciers to wetlands.The energy budget of two glaciers,i.e.Xiao Dongkemadi and Parlung No.4,was studied by means of extended field measurements and a distributed model of the coupled energy and mass balance was developed and evaluated.The need for accurate characterization of surface albedo was further documented for the entire Qinghai Tibet Plateau by numerical experiments with Weather Research and Forecast(WRF)on the sensitivity of the atmospheric boundary layer to the parameterization of land surface processes.A new approach to the calibration of a coupled distributed watershed model of the energy and water balance was demonstrated by a case study on the Heihe River Basin in northwestern China.The assimilation of land surface temperature did lead to the retrieval of critical soil and vegetation properties as the soil permeability and the canopy resistance to the exchange of vapour and carbon dioxide.The retrievals of actual Evapo-Transpiration(ET)were generated by the ETMonitor system and evaluated against eddy covariance measurements at sites spread throughout Asia.As regards glacier response to climate variability,the combined findings based on satellite data and model experiments showed that the spatial variability of surface albedo and temperature is significant and controls both glacier mass balance and flow.Experiments with both atmospheric and hydrosphere-cryosphere models documented the need and advantages of using accurate retrievals of land surface albedo to capture lan-atmosphere interactions at high elevation.展开更多
In this study, recurrent networks to downscale meteorological fields of the ERA-40 re-analysis dataset with focus on the meso-scale water balance were investigated. Therefore two types of recurrent neural networks wer...In this study, recurrent networks to downscale meteorological fields of the ERA-40 re-analysis dataset with focus on the meso-scale water balance were investigated. Therefore two types of recurrent neural networks were used. The first approach is a coupling between a recurrent neural network and a distributed watershed model and the second a nonlinear autoregressive with exogenous inputs (NARX) network, which directly predicted the component of the water balance. The approaches were deployed for a meso-scale catchment area in the Free State of Saxony, Germany. The results show that the coupled approach did not perform as well as the NARX network. But the meteorological output of the coupled approach already reaches an adequate quality. However the coupled model generates as input for the watershed model insufficient daily precipitation sums and not enough wet days were predicted. Hence the long-term annual cycle of the water balance could not be preserved with acceptable quality in contrary to the NARX approach. The residual storage change term indicates physical restrictions of the plausibility of the neural networks, whereas the physically based correlations among?the components of the water balance were preserved more accurately by the coupled approach.展开更多
Background:This study aims to assess the effects of a forestation program and climate change on the annual and seasonal water balance of the Bogowonto catchment(597 km^(2))in Java,Indonesia.The catchment study is rare...Background:This study aims to assess the effects of a forestation program and climate change on the annual and seasonal water balance of the Bogowonto catchment(597 km^(2))in Java,Indonesia.The catchment study is rare example in Indonesia where forestation has been applied at the catchment level.However,since the forestation program has been initiated,evaluations of the program only focus on the planting area targets,while the environmental success e.g.,impacts on the hydrological processes have never been assessed.This study used a calibrated Soil and Water Assessment Tool(SWAT)model to diagnose the isolated and combined effects of forestation and climate change on five water balance components,namely streamflow(Q),evapotranspiration(ET),surface runoff(Q_(s)),lateral flow(Q_(l))and base flow(Q_(b)).Results:The results show that from 2006 to 2019,forest cover has increased from 2.7% to 12.8% of the total area,while in the same period there was an increase in the mean annual and seasonal temperature,rainfall,and streamflow.Results of SWAT simulations show that changes in the mean annual and seasonal water balance under the forestation only scenario were relatively minor,while changes were more pronounced under the climate change only scenario.Based on the combined impacts scenario,it was observed that the effects of a larger forest area on the water balance were smaller than the effects of climate change.Conclusions:Although we found that forestation program has minor impacts compared to that of climate change on the hydrological processes in the Bogowonto catchment,seasonally,forestation activity has decreased the streamflow and surface runoff during the wet season which may reduce the risk of moderate floods.However,much attention should be paid to the way how forestation may result in severe drought events during the dry season.Finally,we urge the importance of accounting for the positive and negative effects in future forestation programs.展开更多
Considering the water restrictions,it is important to check the water balance in each area.These restrictions are even more important in arid and semi-arid regions.The purpose of this study was to study the water bala...Considering the water restrictions,it is important to check the water balance in each area.These restrictions are even more important in arid and semi-arid regions.The purpose of this study was to study the water balance in the Kalacho plain of Kohgiluyeh city.Kalacho plain is about 15 km east of Dehdasht city.In recent years,due to the excessive extraction of lowland wells,the quality of groundwater has also declined steadily.Therefore,hydrogeological assessment and aquifer management seems necessary.Groundwater management requires understanding and functioning of the aquifer under natural conditions(firstly)and then predicting the effects of harvesting or feeding.Undoubtedly,understanding the actual behaviors of a natural system requires some research for each particular area.The average annual temperature and precipitation in the meteorological stations is about 18.1°C and 394 mm,respectively.The water crisis map of this plain has been prepared based on the data of 45 km2 area during the 1991-1992 blue water year.Groundwater Balance Range of the Kalacho Plain is selected based on available statistics and distribution of piezometers,wells and agricultural areas.According to the long-term hydrograph,the plain faces an average loss of 0.15 m and a reservoir deficit of 2.5 million m3.Also during the 20-year period,a total of 24 m of drop and 68 million cubic meters of reservoir deficits were created in the plain.By calculating the effective parameters in the general water balance equation(inputs and outputs),the plain was finally divided into five critical areas.Zones 1,2 and 3 are the most critical lowland areas in the vicinity of the hydraulic connection with the Gachsaran Fm.,and areas 4 and 5 are less critical because of the adjacent Asmari Formation,which feed on this karstic aquifer.Overall,this negative balance indicates an increasing drop in groundwater level and its reservoir deficit.展开更多
Tropical regions along the Andean Cordillera face an uncertain future as mountain lakes and snow peaks exhibit receding trends associated with factors such as climatic precursors and local anthropogenic activities. To...Tropical regions along the Andean Cordillera face an uncertain future as mountain lakes and snow peaks exhibit receding trends associated with factors such as climatic precursors and local anthropogenic activities. Tota, the largest mountain lake in the Colombian Andes, exemplifies the role played by these factors on the lake's hydrologic evolution. A monthly water balance in Tota Lake was performed using available hydrological information from 1958 to 2007 to address interannual and multiannual level fluctuations associated with human activities and climatic precursors. The balance shows that net water uses fluctuated around 2 m3/s during this period with a pattern that, although constrained during years of severe decline in lake levels, is able to explain most of the multiannual decaying trend of 1.5 cm/year in the last 50 years. The lake’s naturalized levels were used to determine the influence of climate precursors on the lake evolution. Using Multichannel Singular Spectrum Analysis (M-SSA), significant five-year ENSO and 20-year PDO related quasi-oscillations were detected, explaining 54% of the variance associated with mean annual naturalized level fluctuations. ENSO is markedly in-phase with lake levels, with critical declines associated with low precipitation and high evaporation rates during El Ni?o years, whereas the PDO signal exhibits a phase opposition with lake levels, with low naturalized levels during a positive PDO phase and high levels during a negative PDO phase (an important result to consider given the current cooling trend of the PDO signal).展开更多
Calculation of the water balance is very important to relieve the pressure on water resources in arid agricultural irrigation areas.This research focused on irrigation water balance calculations in the Manas River Bas...Calculation of the water balance is very important to relieve the pressure on water resources in arid agricultural irrigation areas.This research focused on irrigation water balance calculations in the Manas River Basin of the southern margin of the Junggar Basin of China,and aimed to analyze the groundwater level dynamic trend and response characteristics of the basin water cycle under water-saving irrigation measures.The surface water and groundwater coupling model of MIKE 11-Visual MODFLOW was used to simulate rainfall runoff in mountainous areas,and quantify the contribution of water balance components in the plain irrigation area.Convergence of the delayed watershed in the mountain area was obvious,and when the river runoff exceeded 200 m^(3)/s,the error in the runoff simulation was large.The water balance in the plain agricultural irrigation area was in a negative equilibrium state,and the difference between recharge and discharge was−2.65 billion m^(3).The evapotranspiration was 24.49 billion m^(3) under drip irrigation,accounting for only approximately 51%of the total discharge.The lateral discharge of the unsaturated and saturated aquifers was 15.38 billion m^(3),accounting for approximately 32%of the total discharge.The main reason for the groundwater decline in the irrigation area was closely related to the extraction of groundwater,because the amount of recharge and discharge in the natural state was approximately identical.The MIKE 11-Visual MODFLOW model produced accurate results,and the research method provided a new exploration technique to quantify the effect of water supply mode on the groundwater table.The model is suitable for the management of water resources in arid areas.展开更多
In this study,an approach that integrates airborne imagery data as inputs was used to improve the estimation of soil water deficit(SWD)for maize and sunflower grown under full and deficit irrigation treatments.The pro...In this study,an approach that integrates airborne imagery data as inputs was used to improve the estimation of soil water deficit(SWD)for maize and sunflower grown under full and deficit irrigation treatments.The proposed model was applied to optimize the maximum total available soil water(TAWr)by minimizing the difference between a water stress coefficient ks and crop water stress index(1-CWSI).The optimal value of maximum TAWr was then used to calibrate a soil water balance model which in turn updated the estimation of soil water deficit.The estimates of SWD in the soil profile of both irrigated maize and sunflower fields were evaluated with the crop root zone SWD derived from neutron probe measurements and the FAO-56 SWD procedure.The results indicated a good agreement between the estimated SWD from the proposed approach and measured SWD for both maize and sunflower.The statistical analyses indicated that the maximum TAWr estimated from CWSI significantly improved the estimates of SWD,which reduced the mean absolute error(MAE)and root mean square error(RMSE)by 40%and 44%for maize and 22%for sunflower,compared with the FAO-56 model.The proposed procedure works better for crops under deficit irrigation condition.With the availability of higher spatial and temporal resolution airborne imagery during the growing season,the optimization procedure can be further improved.展开更多
The ecology of Qilian Mountains has been seriously threatened by uncontrolled grazing and wasteland reclamation. This study examined the ecological changes on the southern slope of Qilian Mountains in China from the p...The ecology of Qilian Mountains has been seriously threatened by uncontrolled grazing and wasteland reclamation. This study examined the ecological changes on the southern slope of Qilian Mountains in China from the perspective of water conservation by classifying different clusters of water conservation functional areas to efficiently use limited human resources to tackle the water conservation protection problem. In this study, we used Integrate Valuation of Ecosystem Services and Tradeoffs(InVEST) model to estimate water conservation and analyzed the factors that influence the function. The results of this study include:(1) from 2000 to 2015, the water conservation of the southern slope of Qilian Mountains generally showed an increasing trend, and the total water conservation in 2015 increased by 42.18% compared with that in 2000.(2) Rainfall, fractional vegetation cover(FVC), and evapotranspiration have the most significant influence on the water conservation of the study area. Among them, water conservation is positively correlated with rainfall and FVC(P<0.05) and negatively correlated with evapotranspiration(P<0.05).(3) The importance level of water conservation functional areas gradually increases from northwest to southeast, and the region surrounding Menyuan Hui Autonomous County in the southeast of the southern slope of Qilian Mountains is the core water conservation functional area. And(4) the study area was divided into five clusters(Cluster Ⅰ–Cluster Ⅴ) of water conservation, with the areas of Clusters Ⅰ through Ⅴ accounting for 0.58%, 13.74%, 41.23%, 32.43%, and 12.01% of the whole study area, respectively.展开更多
The effects of catchment characteristics and climate variables on water partitioning into evapotranspiratio n and runoff can be evaluated using the Budyko framework.However,the influence of glaciers on catchment chara...The effects of catchment characteristics and climate variables on water partitioning into evapotranspiratio n and runoff can be evaluated using the Budyko framework.However,the influence of glaciers on catchment characteristics within the framework has yet been adequately investigated.Here we extend the Budyko framework and apply the elasticity method to examine the effects of glaciers on runoff between 2001 and 2010 in 25 upstream catchments of the Tarim River Basin in western China.The consideration of glacier mass balance and glacier fraction improves the performance of the Budyko framework,especially for the catchments with a high glacier fraction.We found that the catchment characteristic parameterwas strongly affected by glacier fraction,and it changes from 1.15 to 2.09 when glacier fraction decreases from 0.4191 to 0.0005.This also reflects the change in water-energy partitioning that eventually effects on evapotranspiration and runoff.We further assessed the average runoff responses to changes in precipitation,potential evapotranspiration,glacier mass balance,and glacier fraction in the 25 catchments.Although the runoff appears most sensitive to precipitation in average,its sensitivity to glacier mass balance and glacier area in fact rises from-0.07%to 0.17% and about 0-0.54%,respectively,when the glacier fraction increases from 0.0005 to 0.4191,further demonstrating the increasing influence of glaciers when the fraction becomes larger.After all,the inclusion of glacier factors in the Budyko framework allows us to understand more about the impacts and contributions of glaciers to runoff at a catchment scale.展开更多
The article puts forward the process and means of regional water and land balance research, and then from two scenarios which are the balances under natural regulation and human intervention, calculated and analysed t...The article puts forward the process and means of regional water and land balance research, and then from two scenarios which are the balances under natural regulation and human intervention, calculated and analysed the balance between water and land on Ningxia Plain. For the balance under natural regulation named farmland water balance, using farmland water resource balance equation, the research estimated the monthly farmland water balance of 8 major crops for all of the 12 counties on Ningxia Plain in the period of 1960-2001; for the balance under human intervention, the research estimated land-use water balance equation of the counties in 2000, and calculated the balance between land use and water resources including irrigating water of all the 12 counties on Ningxia Plain. Results showed that①precipitation can not meet the water demand of the crops for growth and development on Ningxia Plain, and water shortage is the primary character of farmland water balance under natural regulation,②the diversity of water and land balance of different counties is distinctly influenced by the crop structure, water quantity for irrigation and irrigation level.③Irrigation water could meet the crop water demand on Ningxia Plain in 2000, but there was not much space to expand irrigating cultivated land.展开更多
The North China Plain(NCP)is a major grain production area in China,but the current winter wheatsummer maize system has resulted in a large water deficit.This water-shortage necessitates the improvement of crop water ...The North China Plain(NCP)is a major grain production area in China,but the current winter wheatsummer maize system has resulted in a large water deficit.This water-shortage necessitates the improvement of crop water productivity in the NCP.A crop water model,AquaCrop,was adopted to investigate yield and water productivity(WP)for rain-fed summer maize on the piedmont of the NCP.The data sets to calibrate and validate the model were obtained from a 3-year(2011–2013)field experiment conducted on the Yanshan piedmont of the NCP.The range of root mean square error(RMSE)between the simulated and measured biomass was 0.67–1.25 t·hm^(–2),and that of relative error(RE)was 9.4%–15.4%,the coefficient of determination(R^(2))ranged from 0.992 to 0.994.The RMSE between the simulated and measured soil water storage at depth of 0–100 cm ranged from 4.09 to 4.39 mm;and RE and R^(2) in the range of 1.07%–1.20%and 0.880–0.997,respectively.The WP as measured by crop yield per unit evapotranspiration was 2.50–2.66 kg·m^(–3).The simulated impact of long-term climate(i.e.,1980–2010)and groundwater depth on crop yield and WP revealed that the higher yield and WP could be obtained in dry years in areas with capillary recharge from groundwater,and much lower values elsewhere.The simulation also suggested that supplementary irrigation in areas without capillary groundwater would not result in groundwater over-tapping since the precipitation can meet the water required by both maize and ecosystem,thus a beneficial outcome for both food and ecosystem security can be assured.展开更多
The effective recovery of water level is a crucial measure of the success of comprehensive groundwater over-exploitation management actions in North China.However,traditional evaluation method do not directly capture ...The effective recovery of water level is a crucial measure of the success of comprehensive groundwater over-exploitation management actions in North China.However,traditional evaluation method do not directly capture the relationship between mining and other equilibrium elements.This study presents an innovative evaluation method to assess the water level recovery resulting from mining reduction based on the relationship between variation in exploitation and recharge.Firstly,the recharge variability of source and sink terms for both the base year and evaluation year is calculated and the coefficient of recharge variationβis introduced,which is then used to calculate the effective mining reduction and solve the water level recovery value caused by the effective mining reduction,and finally the water level recovery contribution by mining reduction is calculated by combining with the actual volume of mining reduction in the evaluation area.This research focuses on Baoding and Shijiazhuang Plain area,which share similar hydrogeological conditions but vary in groundwater exploitation and utilization.As the effect of groundwater level recovery with mining reduction was evaluated in these two areas as case study.In 2018,the results showed an effective water level recovery of 0.17 m and 0.13 m in the shallow groundwater of Shijiazhuang and Baoding Plain areas,respectively.The contributions of recovery from mining reduction were 76%and 57.98%for these two areas,respectively.It was notable that the water level recovery was most prominent in the foothill plain regions.From the evaluation results,it is evident that water level recovery depends not only on the intensity of groundwater mining reduction,but also on its effectiveness.The value of water level recovery alone cannot accurately indicate the intensity of mining reduction,as recharge variation significantly influences water level changes.Therefore,in practice,it is crucial to comprehensively assess the impact of mining reduction on water level recovery by combining the coefficient of recharge variation with the contribution of water level recovery from mining reduction.This integrated approach provide a more reasonable and scientifically supported basis,offering essential data support for groundwater management and conservation.To improve the accuracy and reliability of evaluation results,future work will focus on the standardizing and normalizing raw data processing.展开更多
In the hydrological watershed, some natural processes take place in which the interaction of water, soil, climate and vegetation favors the capture of water. The present study aimed to evaluate preliminary information...In the hydrological watershed, some natural processes take place in which the interaction of water, soil, climate and vegetation favors the capture of water. The present study aimed to evaluate preliminary information regarding the hydrological response and the water balance in a small research watershed with tropical forest cover (15°01'44''N and 92°13'55''W, 471 m, 2.3 has). Events of precipitation, direct runoff, infiltration rate and baseflow were performed. The amount, duration and intensity of rainfall events were recorded with the use of a pluviograph. Surface runoff was quantified with an established gauging station, an H-type gauging device and a horizontal mechanical gauging limnograph. Runoff base flow was measured at the gauging station using the volume-time method. Infiltration was measured using a triple ring infiltrometer, taking two measurements in the upper part and two in the lower part of the microbasin. Evapotranspiration was measured with the amount of rainfall entering and runoff leaving the watershed. In the study period, annual rainfall of 4417.6 mm distributed over 181 events were recorded;about 70% of the storms showed lower intensities at 20 mm·h<sup>-1</sup>. The total runoff was 345.8 mm caused by half of the rainfall events, which represents 7.8% of the total rain;77% of runoff events showed lower sheets of 5 mm and an average specific rate of 20.7 L·s<sup>-1</sup>·ha<sup>-1</sup> with a maximum of 113.6 L·s<sup>-1</sup>·ha<sup>-1</sup>. Three runoff events were greater than 20.1 mm and caused the 22.5% of the total runoff depth in the study period showing the equilibrium conditions in the hydrological response of the forest. Water outputs like baseflow was 669.5 mm. In this way, 90% of the rainfall is infiltrated every year in the micro-watershed, which shows the importance of the plant cover in the hydrological regulation and the groundwater recharge.展开更多
Hyaluronic acid (HA) preparations have emerged as pivotal components in contemporary dentistry, gaining widespread recognition for their multifaceted roles in various biological functions. Extensive literature undersc...Hyaluronic acid (HA) preparations have emerged as pivotal components in contemporary dentistry, gaining widespread recognition for their multifaceted roles in various biological functions. Extensive literature underscores the significance of HA in maintaining tissue water balance, fostering cell proliferation, promoting rapid cell migration, influencing cell differentiation during organism development, and facilitating tissue regeneration. Notably, HA’s interactions with cell surface receptors contribute to the viscosity of synovial fluid, activate the immune system, and enhance cartilage elasticity. Beyond these established functions, HA has also been investigated for its potential involvement in determining and studying the hormetic effects of radon water, adding a novel dimension to its applications in dental research. A thorough exploration of existing studies reveals a nuanced understanding of how HA interventions impact the outcomes of dental procedures. The comprehensive scope of these investigations allows for a more accurate assessment of the potential effectiveness of specific interventions and provides valuable insights into post-procedural prognoses for individual patients. This synthesis of literature serves as the foundation for elucidating the intricate interplay between HA, radon exposure, and their relevance in modern dental practices.展开更多
Landslides are highly dangerous phenomena that occur in different parts of the world and pose significant threats to human populations. Intense rainfall events are the main triggering process for landslides in urbaniz...Landslides are highly dangerous phenomena that occur in different parts of the world and pose significant threats to human populations. Intense rainfall events are the main triggering process for landslides in urbanized slope regions, especially those considered high-risk areas. Various other factors contribute to the process;thus, it is essential to analyze the causes of such incidents in all possible ways. Soil moisture plays a critical role in the Earth’s surface-atmosphere interaction systems;hence, measurements and their estimations are crucial for understanding all processes involved in the water balance, especially those related to landslides. Soil moisture can be estimated from in-situ measurements using different sensors and techniques, satellite remote sensing, hydrological modeling, and indicators to index moisture conditions. Antecedent soil moisture can significantly impact runoff for the same rainfall event in a watershed. The Antecedent Precipitation Index (API) or “retained rainfall,” along with the antecedent moisture condition from the Natural Resources Conservation Service, is generally applied to estimate runoff in watersheds where data is limited or unavailable. This work aims to explore API in estimating soil moisture and establish thresholds based on landslide occurrences. The estimated soil moisture will be compared and calibrated using measurements obtained through multisensor capacitance probes installed in a high-risk area located in the mountainous region of Campos do Jordão municipality, São Paulo, Brazil. The API used in the calculation has been modified, where the recession coefficient depends on air temperature variability as well as the climatological mean temperature, which can be considered as losses in the water balance due to evapotranspiration. Once the API is calibrated, it will be used to extrapolate to the entire watershed and consequently estimate soil moisture. By utilizing recorded mass movements and comparing them with API and soil moisture, it will be possible to determine thresholds, thus enabling anticipation of landslide occurrences.展开更多
The lower Ili River Basin is located in semi-arid area, and the annual rainfall is 177 mm. Therefore, the irrigation is inevitable for agriculture. Large-scale irrigated agriculture had been developed since 1960's...The lower Ili River Basin is located in semi-arid area, and the annual rainfall is 177 mm. Therefore, the irrigation is inevitable for agriculture. Large-scale irrigated agriculture had been developed since 1960's in the lower parts of the river and the total irrigated area is about 32 000 hm2. In the project area, the paddy rice-upland crop rotation has been practiced. Due to the domestic water use for hydropower and agriculture as well as water use among riparian countries, the deficit of water for agriculture in the lower part has been concerned. The authors, therefore, conducted the field survey and water balance analysis of the Akdara irrigation project in the lower Ili River Basin in order to assess the land and water uses. Moreover, the impact of the water use on water environment to the basin was analyzed. The following results were obtained as following (1) the groundwater level in the irrigated district varied from 1.5 m to 3.5 m through year. (2) 1970's groundwater level was drastically raised from 8 m to 3 m and the groundwater had been recharged in this period. (3) Water use efficiency of agriculture, which is the ratio of total evapotranspiration to the total water withdrawal was as low as 0.23.展开更多
文摘Hydrological models are very useful tools for evaluating water resources, and the hydroclimatic hazards associated with the water cycle. However, their calibration and validation require the use of performance criteria which choice is not straightforward. This paper aims to evaluate the influence of the performance criteria on water balance components and water extremes using two global rainfall-runoff models (HBV and GR4J) over the Ouémé watershed at the Bonou and Savè outlets. Three (3) Efficacy criteria (Nash, coefficient of determination, and KGE) were considered for calibration and validation. The results show that the Nash criterion provides a good assessment of the simulation of the different parts of the hydrograph. KGE is better for simulating peak flows and water balance elements than other efficiency criteria. This study could serve as a basis for the choice of performance criteria in hydrological modelling.
基金jointly supported by the National Natural Science Foundation of China (32171679 and 32201475)。
文摘Accurate estimation of crop evapotranspiration(ETc) and soil water balance, which is vital for optimizing water management strategy in crop production, can be performed by simulation. But existing software has many deficiencies, including complex operation, limited scalability, lack of batch processing, and a single ETc model. Here we present simET, an open-source software package written in the R programming language. Many concepts involved in crop ETc simulation are condensed into functions in the package. It includes three widely used crop ETc models built on these functions: the single-crop coefficient,double-crop coefficient, and Shuttleworth–Wallace models, along with tools for preparing model data and comparing estimates. SimET supports ETc simulation in crops with repeated growth cycles such as alfalfa, a perennial forage crop that is cut multiple times annually.
文摘The aim of this study is to evaluate the hydrological impacts of climate change on the water balance of Lake Tana in Ethiopia. Impact assessments are by downscaled General Circulation Model (GCM) output and hydrological modeling. For A2 and B2 emission scenarios, precipitation, maximum and minimum temperature estimates from the HadCM3 GCM were used. GCM output was downscaled using the Statistical DownScaling Model (SDSM 4.2). Impact analyses were applied for three future time periods: early, mid and late 21st century. Over-lake evaporation is estimated by Hardgrave’s method, and over-lake precipitation is estimated by inverse distance weighing interpolation, whereas inflows from gauged and ungauged catchments are simulated by the HBV hydrological model. Findings indicate increases in maximum and minimum temperature on annual base for both emission scenarios. The projection of mean annual over lake precipitation for both A2 and B2 emission scenarios shows increasing pattern for 21st century in comparison to the baseline period. The increase of mean annual precipitation for A2 emission scenario is 9% (112 mm/year), 10% (125 mm/year) and 11% (137 mm/year) for the three future periods respectively. B2 emission scenario mean annual precipitation shows increase by 9% (111 mm/year), 10% (122 mm/year) and 10% (130 mm/year) respectively for the three future periods. Findings indicate consistent increases of lake storage for all three future periods for both A2 and B2 emission scenarios.
基金Chinese Academy of Sciences CAS Earth Project(No.XAD19070102)National Natural Science Foundation of China(No.91737205)+3 种基金SAFEA Long-Term-Projects of the 1000 Talent Plan for High-Level Foreign Experts(No.WQ20141100224)Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA19030203)Key Research Program of Frontier Sciences of Chinese Academy of Sciences(No.QYZDJ-SSW-DQC019)European Space Agency Dragon 4 Program(ESRIN/Contract No.4000121196/17/I-NB)。
文摘Observation and modeling of the coupled energy and water balance is the key to understand hydrospheric and cryospheric processes at high elevation.The paper summarizes the progress to address this aspect in relation with different earth system elements,from glaciers to wetlands.The energy budget of two glaciers,i.e.Xiao Dongkemadi and Parlung No.4,was studied by means of extended field measurements and a distributed model of the coupled energy and mass balance was developed and evaluated.The need for accurate characterization of surface albedo was further documented for the entire Qinghai Tibet Plateau by numerical experiments with Weather Research and Forecast(WRF)on the sensitivity of the atmospheric boundary layer to the parameterization of land surface processes.A new approach to the calibration of a coupled distributed watershed model of the energy and water balance was demonstrated by a case study on the Heihe River Basin in northwestern China.The assimilation of land surface temperature did lead to the retrieval of critical soil and vegetation properties as the soil permeability and the canopy resistance to the exchange of vapour and carbon dioxide.The retrievals of actual Evapo-Transpiration(ET)were generated by the ETMonitor system and evaluated against eddy covariance measurements at sites spread throughout Asia.As regards glacier response to climate variability,the combined findings based on satellite data and model experiments showed that the spatial variability of surface albedo and temperature is significant and controls both glacier mass balance and flow.Experiments with both atmospheric and hydrosphere-cryosphere models documented the need and advantages of using accurate retrievals of land surface albedo to capture lan-atmosphere interactions at high elevation.
基金supported by the Erasmus Mundus Action 2 Programme of the European Union and the German Weather Service(DWD)and the Czech Hydrological-Meteorological Service(CHMI).
文摘In this study, recurrent networks to downscale meteorological fields of the ERA-40 re-analysis dataset with focus on the meso-scale water balance were investigated. Therefore two types of recurrent neural networks were used. The first approach is a coupling between a recurrent neural network and a distributed watershed model and the second a nonlinear autoregressive with exogenous inputs (NARX) network, which directly predicted the component of the water balance. The approaches were deployed for a meso-scale catchment area in the Free State of Saxony, Germany. The results show that the coupled approach did not perform as well as the NARX network. But the meteorological output of the coupled approach already reaches an adequate quality. However the coupled model generates as input for the watershed model insufficient daily precipitation sums and not enough wet days were predicted. Hence the long-term annual cycle of the water balance could not be preserved with acceptable quality in contrary to the NARX approach. The residual storage change term indicates physical restrictions of the plausibility of the neural networks, whereas the physically based correlations among?the components of the water balance were preserved more accurately by the coupled approach.
基金funded by the publication grant scheme from the Publishers and Publications Board(BPP),Universitas Gadjah Mada,Indonesia.
文摘Background:This study aims to assess the effects of a forestation program and climate change on the annual and seasonal water balance of the Bogowonto catchment(597 km^(2))in Java,Indonesia.The catchment study is rare example in Indonesia where forestation has been applied at the catchment level.However,since the forestation program has been initiated,evaluations of the program only focus on the planting area targets,while the environmental success e.g.,impacts on the hydrological processes have never been assessed.This study used a calibrated Soil and Water Assessment Tool(SWAT)model to diagnose the isolated and combined effects of forestation and climate change on five water balance components,namely streamflow(Q),evapotranspiration(ET),surface runoff(Q_(s)),lateral flow(Q_(l))and base flow(Q_(b)).Results:The results show that from 2006 to 2019,forest cover has increased from 2.7% to 12.8% of the total area,while in the same period there was an increase in the mean annual and seasonal temperature,rainfall,and streamflow.Results of SWAT simulations show that changes in the mean annual and seasonal water balance under the forestation only scenario were relatively minor,while changes were more pronounced under the climate change only scenario.Based on the combined impacts scenario,it was observed that the effects of a larger forest area on the water balance were smaller than the effects of climate change.Conclusions:Although we found that forestation program has minor impacts compared to that of climate change on the hydrological processes in the Bogowonto catchment,seasonally,forestation activity has decreased the streamflow and surface runoff during the wet season which may reduce the risk of moderate floods.However,much attention should be paid to the way how forestation may result in severe drought events during the dry season.Finally,we urge the importance of accounting for the positive and negative effects in future forestation programs.
文摘Considering the water restrictions,it is important to check the water balance in each area.These restrictions are even more important in arid and semi-arid regions.The purpose of this study was to study the water balance in the Kalacho plain of Kohgiluyeh city.Kalacho plain is about 15 km east of Dehdasht city.In recent years,due to the excessive extraction of lowland wells,the quality of groundwater has also declined steadily.Therefore,hydrogeological assessment and aquifer management seems necessary.Groundwater management requires understanding and functioning of the aquifer under natural conditions(firstly)and then predicting the effects of harvesting or feeding.Undoubtedly,understanding the actual behaviors of a natural system requires some research for each particular area.The average annual temperature and precipitation in the meteorological stations is about 18.1°C and 394 mm,respectively.The water crisis map of this plain has been prepared based on the data of 45 km2 area during the 1991-1992 blue water year.Groundwater Balance Range of the Kalacho Plain is selected based on available statistics and distribution of piezometers,wells and agricultural areas.According to the long-term hydrograph,the plain faces an average loss of 0.15 m and a reservoir deficit of 2.5 million m3.Also during the 20-year period,a total of 24 m of drop and 68 million cubic meters of reservoir deficits were created in the plain.By calculating the effective parameters in the general water balance equation(inputs and outputs),the plain was finally divided into five critical areas.Zones 1,2 and 3 are the most critical lowland areas in the vicinity of the hydraulic connection with the Gachsaran Fm.,and areas 4 and 5 are less critical because of the adjacent Asmari Formation,which feed on this karstic aquifer.Overall,this negative balance indicates an increasing drop in groundwater level and its reservoir deficit.
文摘Tropical regions along the Andean Cordillera face an uncertain future as mountain lakes and snow peaks exhibit receding trends associated with factors such as climatic precursors and local anthropogenic activities. Tota, the largest mountain lake in the Colombian Andes, exemplifies the role played by these factors on the lake's hydrologic evolution. A monthly water balance in Tota Lake was performed using available hydrological information from 1958 to 2007 to address interannual and multiannual level fluctuations associated with human activities and climatic precursors. The balance shows that net water uses fluctuated around 2 m3/s during this period with a pattern that, although constrained during years of severe decline in lake levels, is able to explain most of the multiannual decaying trend of 1.5 cm/year in the last 50 years. The lake’s naturalized levels were used to determine the influence of climate precursors on the lake evolution. Using Multichannel Singular Spectrum Analysis (M-SSA), significant five-year ENSO and 20-year PDO related quasi-oscillations were detected, explaining 54% of the variance associated with mean annual naturalized level fluctuations. ENSO is markedly in-phase with lake levels, with critical declines associated with low precipitation and high evaporation rates during El Ni?o years, whereas the PDO signal exhibits a phase opposition with lake levels, with low naturalized levels during a positive PDO phase and high levels during a negative PDO phase (an important result to consider given the current cooling trend of the PDO signal).
基金support from the National Natural Science Fund(41601579,41361096)National Key Development Program(2017YFC0404303,2017YFC0404304,2016YFC0501402)Excellent Youth Teachers Program of Xinjiang Production&Construction Corps(CZ027204).
文摘Calculation of the water balance is very important to relieve the pressure on water resources in arid agricultural irrigation areas.This research focused on irrigation water balance calculations in the Manas River Basin of the southern margin of the Junggar Basin of China,and aimed to analyze the groundwater level dynamic trend and response characteristics of the basin water cycle under water-saving irrigation measures.The surface water and groundwater coupling model of MIKE 11-Visual MODFLOW was used to simulate rainfall runoff in mountainous areas,and quantify the contribution of water balance components in the plain irrigation area.Convergence of the delayed watershed in the mountain area was obvious,and when the river runoff exceeded 200 m^(3)/s,the error in the runoff simulation was large.The water balance in the plain agricultural irrigation area was in a negative equilibrium state,and the difference between recharge and discharge was−2.65 billion m^(3).The evapotranspiration was 24.49 billion m^(3) under drip irrigation,accounting for only approximately 51%of the total discharge.The lateral discharge of the unsaturated and saturated aquifers was 15.38 billion m^(3),accounting for approximately 32%of the total discharge.The main reason for the groundwater decline in the irrigation area was closely related to the extraction of groundwater,because the amount of recharge and discharge in the natural state was approximately identical.The MIKE 11-Visual MODFLOW model produced accurate results,and the research method provided a new exploration technique to quantify the effect of water supply mode on the groundwater table.The model is suitable for the management of water resources in arid areas.
文摘In this study,an approach that integrates airborne imagery data as inputs was used to improve the estimation of soil water deficit(SWD)for maize and sunflower grown under full and deficit irrigation treatments.The proposed model was applied to optimize the maximum total available soil water(TAWr)by minimizing the difference between a water stress coefficient ks and crop water stress index(1-CWSI).The optimal value of maximum TAWr was then used to calibrate a soil water balance model which in turn updated the estimation of soil water deficit.The estimates of SWD in the soil profile of both irrigated maize and sunflower fields were evaluated with the crop root zone SWD derived from neutron probe measurements and the FAO-56 SWD procedure.The results indicated a good agreement between the estimated SWD from the proposed approach and measured SWD for both maize and sunflower.The statistical analyses indicated that the maximum TAWr estimated from CWSI significantly improved the estimates of SWD,which reduced the mean absolute error(MAE)and root mean square error(RMSE)by 40%and 44%for maize and 22%for sunflower,compared with the FAO-56 model.The proposed procedure works better for crops under deficit irrigation condition.With the availability of higher spatial and temporal resolution airborne imagery during the growing season,the optimization procedure can be further improved.
基金financially supported by the National Key Research and Development Program Project (2017YFC0404304)the National Natural Science Foundation of China (41361005)。
文摘The ecology of Qilian Mountains has been seriously threatened by uncontrolled grazing and wasteland reclamation. This study examined the ecological changes on the southern slope of Qilian Mountains in China from the perspective of water conservation by classifying different clusters of water conservation functional areas to efficiently use limited human resources to tackle the water conservation protection problem. In this study, we used Integrate Valuation of Ecosystem Services and Tradeoffs(InVEST) model to estimate water conservation and analyzed the factors that influence the function. The results of this study include:(1) from 2000 to 2015, the water conservation of the southern slope of Qilian Mountains generally showed an increasing trend, and the total water conservation in 2015 increased by 42.18% compared with that in 2000.(2) Rainfall, fractional vegetation cover(FVC), and evapotranspiration have the most significant influence on the water conservation of the study area. Among them, water conservation is positively correlated with rainfall and FVC(P<0.05) and negatively correlated with evapotranspiration(P<0.05).(3) The importance level of water conservation functional areas gradually increases from northwest to southeast, and the region surrounding Menyuan Hui Autonomous County in the southeast of the southern slope of Qilian Mountains is the core water conservation functional area. And(4) the study area was divided into five clusters(Cluster Ⅰ–Cluster Ⅴ) of water conservation, with the areas of Clusters Ⅰ through Ⅴ accounting for 0.58%, 13.74%, 41.23%, 32.43%, and 12.01% of the whole study area, respectively.
基金This study was financially supported by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(2019QZKK020805)National Natural Science Foundation of China(41690145)+1 种基金supported by Strategic Priority Research Program of Chinese Academy of Sciences(XDA20100305)CAS Pioneer Hundred Talents Program.
文摘The effects of catchment characteristics and climate variables on water partitioning into evapotranspiratio n and runoff can be evaluated using the Budyko framework.However,the influence of glaciers on catchment characteristics within the framework has yet been adequately investigated.Here we extend the Budyko framework and apply the elasticity method to examine the effects of glaciers on runoff between 2001 and 2010 in 25 upstream catchments of the Tarim River Basin in western China.The consideration of glacier mass balance and glacier fraction improves the performance of the Budyko framework,especially for the catchments with a high glacier fraction.We found that the catchment characteristic parameterwas strongly affected by glacier fraction,and it changes from 1.15 to 2.09 when glacier fraction decreases from 0.4191 to 0.0005.This also reflects the change in water-energy partitioning that eventually effects on evapotranspiration and runoff.We further assessed the average runoff responses to changes in precipitation,potential evapotranspiration,glacier mass balance,and glacier fraction in the 25 catchments.Although the runoff appears most sensitive to precipitation in average,its sensitivity to glacier mass balance and glacier area in fact rises from-0.07%to 0.17% and about 0-0.54%,respectively,when the glacier fraction increases from 0.0005 to 0.4191,further demonstrating the increasing influence of glaciers when the fraction becomes larger.After all,the inclusion of glacier factors in the Budyko framework allows us to understand more about the impacts and contributions of glaciers to runoff at a catchment scale.
基金porject KZCX3-SW-333 Supponted by Chinese Academy of Saience
文摘The article puts forward the process and means of regional water and land balance research, and then from two scenarios which are the balances under natural regulation and human intervention, calculated and analysed the balance between water and land on Ningxia Plain. For the balance under natural regulation named farmland water balance, using farmland water resource balance equation, the research estimated the monthly farmland water balance of 8 major crops for all of the 12 counties on Ningxia Plain in the period of 1960-2001; for the balance under human intervention, the research estimated land-use water balance equation of the counties in 2000, and calculated the balance between land use and water resources including irrigating water of all the 12 counties on Ningxia Plain. Results showed that①precipitation can not meet the water demand of the crops for growth and development on Ningxia Plain, and water shortage is the primary character of farmland water balance under natural regulation,②the diversity of water and land balance of different counties is distinctly influenced by the crop structure, water quantity for irrigation and irrigation level.③Irrigation water could meet the crop water demand on Ningxia Plain in 2000, but there was not much space to expand irrigating cultivated land.
基金The authors are grateful for financial support provided by the IAEA(CRP14483)China National Science and Technology Pillar Program(2012BAD05B02).
文摘The North China Plain(NCP)is a major grain production area in China,but the current winter wheatsummer maize system has resulted in a large water deficit.This water-shortage necessitates the improvement of crop water productivity in the NCP.A crop water model,AquaCrop,was adopted to investigate yield and water productivity(WP)for rain-fed summer maize on the piedmont of the NCP.The data sets to calibrate and validate the model were obtained from a 3-year(2011–2013)field experiment conducted on the Yanshan piedmont of the NCP.The range of root mean square error(RMSE)between the simulated and measured biomass was 0.67–1.25 t·hm^(–2),and that of relative error(RE)was 9.4%–15.4%,the coefficient of determination(R^(2))ranged from 0.992 to 0.994.The RMSE between the simulated and measured soil water storage at depth of 0–100 cm ranged from 4.09 to 4.39 mm;and RE and R^(2) in the range of 1.07%–1.20%and 0.880–0.997,respectively.The WP as measured by crop yield per unit evapotranspiration was 2.50–2.66 kg·m^(–3).The simulated impact of long-term climate(i.e.,1980–2010)and groundwater depth on crop yield and WP revealed that the higher yield and WP could be obtained in dry years in areas with capillary recharge from groundwater,and much lower values elsewhere.The simulation also suggested that supplementary irrigation in areas without capillary groundwater would not result in groundwater over-tapping since the precipitation can meet the water required by both maize and ecosystem,thus a beneficial outcome for both food and ecosystem security can be assured.
基金supported by National Natural Science Foundation of China(41972262)Hebei Natural Science Foundation for Excellent Young Scholars(D2020504032).
文摘The effective recovery of water level is a crucial measure of the success of comprehensive groundwater over-exploitation management actions in North China.However,traditional evaluation method do not directly capture the relationship between mining and other equilibrium elements.This study presents an innovative evaluation method to assess the water level recovery resulting from mining reduction based on the relationship between variation in exploitation and recharge.Firstly,the recharge variability of source and sink terms for both the base year and evaluation year is calculated and the coefficient of recharge variationβis introduced,which is then used to calculate the effective mining reduction and solve the water level recovery value caused by the effective mining reduction,and finally the water level recovery contribution by mining reduction is calculated by combining with the actual volume of mining reduction in the evaluation area.This research focuses on Baoding and Shijiazhuang Plain area,which share similar hydrogeological conditions but vary in groundwater exploitation and utilization.As the effect of groundwater level recovery with mining reduction was evaluated in these two areas as case study.In 2018,the results showed an effective water level recovery of 0.17 m and 0.13 m in the shallow groundwater of Shijiazhuang and Baoding Plain areas,respectively.The contributions of recovery from mining reduction were 76%and 57.98%for these two areas,respectively.It was notable that the water level recovery was most prominent in the foothill plain regions.From the evaluation results,it is evident that water level recovery depends not only on the intensity of groundwater mining reduction,but also on its effectiveness.The value of water level recovery alone cannot accurately indicate the intensity of mining reduction,as recharge variation significantly influences water level changes.Therefore,in practice,it is crucial to comprehensively assess the impact of mining reduction on water level recovery by combining the coefficient of recharge variation with the contribution of water level recovery from mining reduction.This integrated approach provide a more reasonable and scientifically supported basis,offering essential data support for groundwater management and conservation.To improve the accuracy and reliability of evaluation results,future work will focus on the standardizing and normalizing raw data processing.
文摘In the hydrological watershed, some natural processes take place in which the interaction of water, soil, climate and vegetation favors the capture of water. The present study aimed to evaluate preliminary information regarding the hydrological response and the water balance in a small research watershed with tropical forest cover (15°01'44''N and 92°13'55''W, 471 m, 2.3 has). Events of precipitation, direct runoff, infiltration rate and baseflow were performed. The amount, duration and intensity of rainfall events were recorded with the use of a pluviograph. Surface runoff was quantified with an established gauging station, an H-type gauging device and a horizontal mechanical gauging limnograph. Runoff base flow was measured at the gauging station using the volume-time method. Infiltration was measured using a triple ring infiltrometer, taking two measurements in the upper part and two in the lower part of the microbasin. Evapotranspiration was measured with the amount of rainfall entering and runoff leaving the watershed. In the study period, annual rainfall of 4417.6 mm distributed over 181 events were recorded;about 70% of the storms showed lower intensities at 20 mm·h<sup>-1</sup>. The total runoff was 345.8 mm caused by half of the rainfall events, which represents 7.8% of the total rain;77% of runoff events showed lower sheets of 5 mm and an average specific rate of 20.7 L·s<sup>-1</sup>·ha<sup>-1</sup> with a maximum of 113.6 L·s<sup>-1</sup>·ha<sup>-1</sup>. Three runoff events were greater than 20.1 mm and caused the 22.5% of the total runoff depth in the study period showing the equilibrium conditions in the hydrological response of the forest. Water outputs like baseflow was 669.5 mm. In this way, 90% of the rainfall is infiltrated every year in the micro-watershed, which shows the importance of the plant cover in the hydrological regulation and the groundwater recharge.
文摘Hyaluronic acid (HA) preparations have emerged as pivotal components in contemporary dentistry, gaining widespread recognition for their multifaceted roles in various biological functions. Extensive literature underscores the significance of HA in maintaining tissue water balance, fostering cell proliferation, promoting rapid cell migration, influencing cell differentiation during organism development, and facilitating tissue regeneration. Notably, HA’s interactions with cell surface receptors contribute to the viscosity of synovial fluid, activate the immune system, and enhance cartilage elasticity. Beyond these established functions, HA has also been investigated for its potential involvement in determining and studying the hormetic effects of radon water, adding a novel dimension to its applications in dental research. A thorough exploration of existing studies reveals a nuanced understanding of how HA interventions impact the outcomes of dental procedures. The comprehensive scope of these investigations allows for a more accurate assessment of the potential effectiveness of specific interventions and provides valuable insights into post-procedural prognoses for individual patients. This synthesis of literature serves as the foundation for elucidating the intricate interplay between HA, radon exposure, and their relevance in modern dental practices.
文摘Landslides are highly dangerous phenomena that occur in different parts of the world and pose significant threats to human populations. Intense rainfall events are the main triggering process for landslides in urbanized slope regions, especially those considered high-risk areas. Various other factors contribute to the process;thus, it is essential to analyze the causes of such incidents in all possible ways. Soil moisture plays a critical role in the Earth’s surface-atmosphere interaction systems;hence, measurements and their estimations are crucial for understanding all processes involved in the water balance, especially those related to landslides. Soil moisture can be estimated from in-situ measurements using different sensors and techniques, satellite remote sensing, hydrological modeling, and indicators to index moisture conditions. Antecedent soil moisture can significantly impact runoff for the same rainfall event in a watershed. The Antecedent Precipitation Index (API) or “retained rainfall,” along with the antecedent moisture condition from the Natural Resources Conservation Service, is generally applied to estimate runoff in watersheds where data is limited or unavailable. This work aims to explore API in estimating soil moisture and establish thresholds based on landslide occurrences. The estimated soil moisture will be compared and calibrated using measurements obtained through multisensor capacitance probes installed in a high-risk area located in the mountainous region of Campos do Jordão municipality, São Paulo, Brazil. The API used in the calculation has been modified, where the recession coefficient depends on air temperature variability as well as the climatological mean temperature, which can be considered as losses in the water balance due to evapotranspiration. Once the API is calibrated, it will be used to extrapolate to the entire watershed and consequently estimate soil moisture. By utilizing recorded mass movements and comparing them with API and soil moisture, it will be possible to determine thresholds, thus enabling anticipation of landslide occurrences.
基金Supported by Global COE Program (Global Center of Excellence for Dryland Science) Funded by MEXT"Historical Interactions between the Multi-Cultural Societies and the Natural Environment in a Semi-Arid Region in Central Eurasia" Project Funded by Research Institute for Humanity and Nature, Japan
文摘The lower Ili River Basin is located in semi-arid area, and the annual rainfall is 177 mm. Therefore, the irrigation is inevitable for agriculture. Large-scale irrigated agriculture had been developed since 1960's in the lower parts of the river and the total irrigated area is about 32 000 hm2. In the project area, the paddy rice-upland crop rotation has been practiced. Due to the domestic water use for hydropower and agriculture as well as water use among riparian countries, the deficit of water for agriculture in the lower part has been concerned. The authors, therefore, conducted the field survey and water balance analysis of the Akdara irrigation project in the lower Ili River Basin in order to assess the land and water uses. Moreover, the impact of the water use on water environment to the basin was analyzed. The following results were obtained as following (1) the groundwater level in the irrigated district varied from 1.5 m to 3.5 m through year. (2) 1970's groundwater level was drastically raised from 8 m to 3 m and the groundwater had been recharged in this period. (3) Water use efficiency of agriculture, which is the ratio of total evapotranspiration to the total water withdrawal was as low as 0.23.
