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This study investigates the interplay between stormwater infiltration devices, shallow groundwater and underground structures (sewer pipes and building foundations) at the neighborhood scale. Considering a hypothetical urban area, different scenarios are designed by varying the underground components taken into account within two soil types. For the least permeable soil, interactions with groundwater reduce the infiltration within devices (−99 to −151 mm/y) and increase the transpiration in surrounding areas (+42 to +50 mm/y). For both soils, the overall water table rise due to infiltration and mounding beneath infiltration devices increases groundwater drainage by sewer pipes and draining systems (+7 to +96 mm/y) and the water elevation differential between opposite walls of impervious structures (up to +1.5 m). In turn, underground structures strongly modify groundwater flow. For the least permeable soil, this directly affects groundwater influence on infiltration and transpiration and thus the overall effects of infiltration strategies at the neighborhood scale. [ABSTRACT FROM AUTHOR]

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The island of Cyprus located in the center of the Eastern Mediterranean Basin, on the sea route from the old world to the west has huge water-based problems. This study, it was aimed to reveal the water deficit and trends on water deficit in the Turkish Republic of Northern Cyprus (KKTC). In this context, the traces of water deficit were investigated using water budgets. Water budgets were created and the amount and duration of water deficit were calculated. Statistically significant trends were investigated in the stations. In this context, the possible trends on the water deficit and the water surplus series were investigated separately. The results of the study showed that water deficit occurs in the KKTC throughout most of the year. The amount and duration of water deficit differ between the northern and inner parts of KKTC. Trend analyzes revealed that there are statistically significant trends in both water deficit and water surplus throughout the KKTC. In addition, a statistically significant decrease trend was detected in the number of months that have water deficit on an annual scale.

Study region: The Touws River in the Klein Karoo region of South Africa Study focus: This study sought to improve the understanding of pool dynamics along non-perennial rivers (NPRs) by utilising the water balance approach to assess the water fluxes that influence pool dynamics in the Touws River. The water balance model made use of various in-situ and satellite-derived data. New hydrological insights: The analysis of the water losses from the pool showed that most of the water was lost through evaporation. The interaction between the pool and groundwater is dependent on the water levels, as the pool loses water to the subsurface up to a certain depth then it starts gaining. When the Wolverfontein 2 pool is full, it can retained water for approximately 258 days without having a surface water inflow. A water balance model was established, and it simulated the water levels with a high correlation of 0.9. This model was also evaluated in the neighbouring pools, and while it simulated the water levels of the upstream pool well, this was not the case for the downstream pool. When remote sensing-derived rainfall and evaporation data were used in the model, the simulated water levels had a slightly lower correlation of 0.7 with the observed water levels. Overall, the remotely sensing-based monthly fluxes estimates could not provide the detailed pool information that was required for the water balance. Errors may have arisen, or they may have been inherited, from any of the three remotely-sensed parameters, namely, the surface area, the rainfall or the evaporation. Although remote sensing did not provide detailed information, it is worth noting that it provides baseline information on the pool dynamics. Overall, this work underscores the relevance of multisource data and the water balance, it helps to better understand the pool dynamics and it will help with the better management of NPRs.

Abstract Hurricane‐induced compound flooding is a combined result of multiple processes, including overland runoff, precipitation, and storm surge. This study presents a dynamical coupling method applied at the boundary of a processes‐based hydrological model (the hydrological modeling extension package of the Weather Research and Forecasting model) and the two‐dimensional Regional Ocean Modeling System on the platform of the Coupled‐Ocean‐Atmosphere‐Wave‐Sediment Transport Modeling System. The coupled model was adapted to the Cape Fear River Basin and adjacent coastal ocean in North Carolina, United States, which suffered severe losses due to the compound flood induced by Hurricane Florence in 2018. The model's robustness was evaluated via comparison against observed water levels in the watershed, estuary, and along the coast. With a series of sensitivity experiments, the contributions from different processes to the water level variations in the estuary were untangled and quantified. Based on the temporal evolution of wind, water flux, water level, and water‐level gradient, compound flooding in the estuary was categorized into four stages: (I) swelling, (II) local‐wind‐dominated, (III) transition, and (IV) overland‐runoff‐dominated. A nonlinear effect was identified between overland runoff and water level in the estuary, which indicated the estuary could serve as a buffer for surges from the ocean side by reducing the maximum surge height. Water budget analysis indicated that water in the estuary was flushed 10 times by overland runoff within 23 days after Florence's landfall.

This paper investigates the relationship between rainfall, groundwater and Gravity Recovery and Climate Experiment (GRACE) data to generate regional-scale estimates of terrestrial water storage variations in the Andalucía region of southern Spain. These estimates can provide information on groundwater depletion (caused by periods of low rainfall or droughts) and groundwater recovery. The spatial distribution of groundwater bodies in southern Spain is complex and current in situ groundwater monitoring methods are deficient, particularly in terms of obtaining representative samples and in implementing and maintaining groundwater monitoring networks. The alternative approach proposed here is to investigate the relationship between precipitation time series and changes in the terrestrial water storage estimated from GRACE observations. The results were validated against the estimated fluctuation in regional groundwater. The maximum correlation between the mean groundwater level and the GRACE observations is 0.69 and this occurs at a lag of one month because the variation in gravity is immediate, but rainfall water requires around one month to travel across the vadose zone before it reaches the groundwater table. Using graphical methods of accumulated deviations from the mean, we show that, in general, groundwater storage follows the smooth, multi-year trends of terrestrial water storage but with less short-term trends; the same is true of rainfall, for which the local trends are more pronounced. There is hysteresis-like behaviour in the variations in terrestrial water storage and in the variations of groundwater. In practical terms, this study shows that, despite the abnormal dryness of the Iberian Peninsula during the 2004–2010 drought, the depleted groundwater storage in Andalucía recovered almost to its pre-drought level by 2016. In addition, groundwater storage and terrestrial water storage show very similar trends but with a delay in the groundwater trend.

Quantification of the water budget of an arid inland river ecosystem is essential but still a challenge for the sustainable development of water resources. In situ observed data were used to analyze the monthly and annual water budgets and the soil hydrological cycle for six typical ecosystems in the Heihe River Basin (HRB). The two-source model was used to partition evapotranspiration (ET) into transpiration (T) and evaporation, after which the validated model was applied to quantitatively analyze the biological water use fraction [T/Ecosystem Water Supply (WS)] for different ecosystems. There were differences in the water budgets of the different ecosystems due to differences in climate, vegetation, soil, and external inputs. Precipitation in the HRB decreased from upstream to downstream, whereas there was a gradual increase in ET. External sources of water (e.g., natural runoff from upstream, irrigation in the middle reaches, and groundwater recharge in the lower reaches) to soil layers played an important role in regulating the water budgets of HRB ecosystems. Cropland obtained the maximum biological water use fraction (0.50), followed by Populus euphratica (0.49), alpine meadow (0.49), alpine swamp meadow (0.44), Tamarix ramosissima (0.42), and Kalidium foliatum (0.4). The soil water residence time (at a depth of 40 cm) varied from 14 d to 97 d (average of 60 d). The order of plant species in terms of soil water residence time was: K. foliatum (88 d) > T. ramosissima (72 d) > alpine meadow (68 d) > alpine swamp meadow (63 d) > cropland (53 d) > P. euphratica forest (20 d). Differences in the biological water use fraction and soil water residence time could be attributed to the characteristics of the water budget for each ecosystem. This study quantified the water budget, biological water use, and soil hydrological cycle across typical ecosystems in HRB, and can act as a reference for ecosystem management of the arid inland river basin. [ABSTRACT FROM AUTHOR]

Environmental changes of the last decades are taking their toll on Lake Sfanta Ana, a crater lake situated in the Eastern Carpathians. The once crystal-clear water of the lake became greenish and turbid in the past decade due to flourishing algae populations, the surface area, depth and the volume of the water body marked a significant decrease during the past century. These changes are considered to be a consequence of sediment transport from the inner slopes of the crater, eutrophication attributed to nutrients of anthropogenic origin and decrease of water level. Having no permanent surface inflow and outflow sources, the water level of the lake depends on other water-budget components like precipitation, overland inflows during high intensity precipitations or snow-melting, evaporation, subsurface inflow and outflow. The research is aimed to identify the main components of the water budget, based on establishing relations between in situ measured meteorological data and the changes of water level. The results indicate a powerful relationship between water level, precipitation, and evaporation, the latter two are the main factors responsible for the variations of the lake's water level. [ABSTRACT FROM AUTHOR]

Water budgets are essential for characterizing water supplies from snow‐dominated upland catchments where data are sparse, groundwater systems are complex, and measurements are prone to error (ε). One solution is imposing water budget closure (CWB) by ignoring difficult‐to‐measure variables, including inter‐basin groundwater fluxes (G) and ε. However, conventional CWB‐based analyses, which derive evapotranspiration (ET) from precipitation (P) and streamflow (Q) (e.g., the Budyko hypothesis), are limited in their ability to take advantage of recent advances in ET products, physically‐based frameworks for improving inferences about G, or tools to statistically characterize ε (Triple Collocation [TC]); all of which offer promise for improved water supply predictions via open water budgets (OWB). We clarify the value of these advances in upland settings by comparing standard land surface model, Ensemble Mean, and TC‐Merged P and ET products in 114 upland catchments. When compared against a long‐term OWB, we find that the CWB assumptions are unsupported in 75%–100% of our 114 catchments, depending on the product. We then show how applying these CWB assumptions in snowy, steep catchments where ε is large can inflate inferences about streamflow response to climate change by up 9 times more than independent (OWB) estimates of ET using TC. Finally, we demonstrate how advances in OWB analysis reveal that high, arid settings with deep permeable substrate are groundwater exporters while most other basins are groundwater importers. Our results highlight the advantages of OWB analyses that harness new products, tools, and frameworks for characterizing inter‐basin groundwater fluxes in critical upland settings. Plain Language Summary: Hydrologists use calculations about the inputs, outputs, and stores of water to anticipate changes in water supply from higher elevation, snow‐dominated (upland) regions. To avoid challenges related to data limitations, it is common to make simplifying assumptions about negligible measurement error and groundwater storage and flow to close the annual water budget. However, the implications of these assumptions are rarely assessed. We investigate the support for these assumptions over a 15‐year period and find that when invalid, they can over inflate the expected sensitivity of streamflow to precipitation falling as snow. We filter some error through optimized averaging (using a method called triple collocation) to illustrate how an open water budget approach that allows for measurement error and groundwater storage and flow can improve our understanding of water resources. This approach illustrates that higher, drier catchments with a deep subsurface provide a groundwater subsidy to lower catchments that is not apparent using other common techniques. Key Points: Closed water budget assumptions about groundwater flux and measurement error are widely unsupported in upland catchmentsTriple Collocation (TC) indicates groundwater export in high arid catchments with deep substrates consistent with a framework by Fan (2019, https://doi.org/10.1002/wat2.1386)The Fan (2019, https://doi.org/10.1002/wat2.1386) framework, TC‐based merging, and independent estimates of evapotranspiration advance upland water budget understanding [ABSTRACT FROM AUTHOR]

The present study aims to improve the efficacy of water budget (WB) estimations from various hydrological data products, by (1) evaluating the uncertainties of hydrological data products, (2) merging four precipitation and six evapotranspiration products using their error variances, and (3) employing the constrained Kalman filter (CKF) method to distribute residual errors among water budget components based on their relative uncertainties. The results show that applying bias correction before the merging process improved estimations of precipitation products with decreasing root mean square error (RMSE), except Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN). Variable Infiltration Capacity (VIC) and bias-corrected Climate Prediction Center Morphing Technique (CMORPH) products outperformed other evapotranspiration and bias-corrected precipitation products, respectively, in terms of mean merging weights. The terrestrial water storage change is the primary reason for non-closure errors, mainly caused by the coarse resolution of Gravity Recovery and Climate Experiment (GRACE). The CKF results were insensitive to variations in uncertainties of runoff. Precipitation derived from the CKF was the best precipitation output, with the highest correlation coefficient (CC) and smallest root mean square deviation (RMSD). [ABSTRACT FROM AUTHOR]

Irrigation is the dominant section of human water use, exerting essential impacts on hydrological processes and water resources. To more realistically simulate irrigation processes in water‐rich regions, an irrigation scheme is incorporated into a land surface‐hydrological model. It calculates the irrigation water requirement according to meteorological conditions, cropping area and growing stage, and root‐zone soil moisture, and determines the irrigation water withdrawal based on the available water resources as well as describing water extraction and irrigation processes in the model. The coupled model is applied to the Yangtze River Basin (YRB) in China, and verified using the observed daily river discharge from 1987 to 1990, evapotranspiration and irrigation amounts from 1999 to 2003. The results first show that the model can well reproduce hydrological processes within the basin, and the simulated irrigation largely agrees with the observation, in terms of annual irrigation and its spatial pattern. Second, inclusion of irrigation processes allows the model to better estimate evapotranspiration, with relative biases decreased from about −10% to −3%. It is also found that in comparison to arid/semi‐arid areas, although presenting a less effect on river discharge and groundwater, the irrigation in the YRB significantly alters hydrological processes through water redistribution. The irrigation‐induced evapotranspiration increment and runoff decrease indicate a shift in the surface water and energy balance, implying a potential effect on the atmosphere. Therefore, representing irrigation processes properly is important, particularly for understanding the coupling effect of the nature‐human system and improving the hydrological prediction accuracy. Plain Language Summary: As the human population has dramatically increased, the agricultural irrigation has grown rapidly over the past 200 years. The critical implications of irrigation on water resources exert through impact on hydrological processes and further influence on weather and climate via the surface energy balance. Representing irrigation processes in the hydrological models or in the climate models is meaningful for improving accuracy of hydrological predictions. Therefore, we described irrigation processes in a land surface‐hydrological model, and the coupled model was used for the YRB in China and verified. It has confirmed that the model appropriately reproduces the hydrological processes impacted by climate variability and human activities. In the future, we intend to use the model to study the coupling effect of the nature‐human systems, which is expected to contribute to sustainable water resources management. Key Points: We developed a land surface‐hydrological model that describes irrigation processes by incorporating an irrigation schemeWe used the Global Crop Water Model method to more realistically estimate irrigation and described water extraction and irrigation processesWe conducted verification in terms of river discharge, evapotranspiration, and irrigation water amount to evaluate model performance [ABSTRACT FROM AUTHOR]

Demand for lithium for batteries is growing rapidly with the global push to decarbonize energy systems. The Salar de Atacama, Chile holds ∼42% of the planet's reserves in the form of brine hosted in massive evaporite aquifers. The mining of these brines and associated freshwater use has raised concerns over the environmental responsibility of lithium extraction, yet large uncertainties remain regarding fundamental aspects of governing hydrological processes in these environments. This incomplete understanding has led to the perpetuation of misconceptions about what constitutes sustainable or renewable water use and therefore what justifies responsible allocation. We present an integrated hydrological assessment using tritium and stable oxygen, and hydrogen isotopes paired with remotely sensed and terrestrial hydroclimate data to define unique sources of water distinguished by residence time, physical characteristics, and connectivity to modern climate. Our results describe the impacts of prolonged drought on surface and groundwaters and demonstrate that nearly all inflow to the basin is composed of water recharged >65 years ago. Still, modern precipitation is critical to sustaining important wetlands around the salar. Recent large rain events have increased surface water and vegetation extents and terrestrial water storage while mining‐related water withdrawals have continued. As we show, poor conceptualizations of these complex hydrological systems have perpetuated the misallocation of water and the misattribution of impacts. These fundamental issues apply to arid regions globally. Our new framework for hydrological assessment in these basins moves beyond calculating gross inputs‐outputs at a steady state to include all compartmentalized stores that constitute "modern" budgets. Plain Language Summary: Lithium is a critical resource for the green energy transition as the primary component in lithium‐ion batteries. Most of the planet's resources occur in water‐scarce environments, like Salar de Atacama, Chile where almost half the world's supply exists. Large amounts of very salty groundwater and some freshwater is extracted to recover the lithium. Yet, persistent gaps remain in our understanding of how water moves in these environments and therefore the impacts its extraction may have on surrounding ecosystems. We employ a combination of satellite and ground‐based hydroclimatological data to assess the system. Our results show that prolonged drought and a subsequent wetter period are the primary drivers of surface hydrology changes and that most of the water here is very old, highlighting the shortcomings of current water allocations. This work presents a data‐driven framework that allows water sustainability and lithium extraction to be adequately assessed in these arid regions. Key Points: Freshwater inflows and the modern water budget at Salar de Atacama are dominated by relic groundwaterA drought coincident with increases in groundwater extraction complicates the attribution of specific anthropogenic environmental impactsFreshwater use and allocated water rights at Salar de Atacama appear to not meet sustainable metrics [ABSTRACT FROM AUTHOR]

Rich ecosystems such as estuaries and brackish lakes are vulnerable to the effects of human activities and are prone to environmental changes. In particular, the salt environment, which is the backbone of the environment, might be affected not only by direct modifications such as dredging but also in ways that were not initially envisioned. Ichkeul Lake, located in the northern part of Tunisia, is a shallow brackish lake registered as a UNESCO World Natural Heritage Site. The construction of reservoirs upstream of the inflowing river in the 1980s reduced the amount of freshwater inflow. That only had been thought to be the cause of the increase in salinity in Ishkeul Lake. On the other hand, the sedimentation in the reservoirs upstream was remarkable, and the supply of sediment from the reservoirs upstream to the Ichkeul Lake was stopped. Changes in sediment outflow may have reduced lakebed altitude and enhanced seawater intrusion. However, the environmental protection measures for the lake so far have focused only on improving the water budget and have not been quantitatively evaluated for sediment transportation. In this study, we first estimated the water budget of the lake. Then the re-suspension by wind disturbance in the lake was estimated from the correlation with the wind speed based on laboratory experiments and field measurements. The outflow of the sediment estimated with these two models was compared with the sediment volume trapped in the upstream reservoirs that would have flowed into the lake if there had been no construction of the dams. Based on this, we evaluated whether the lake is currently erosive or cumulative. As a result, the estimated annual outflow of sediment to the sea was 4300 tons/year. It was estimated that the construction of the reservoirs upstream changed the trend of lakebed height from accumulation to erosion. [ABSTRACT FROM AUTHOR]

Quantifying the inflow and outflow of groundwater is essential to understand the interaction between surface water and groundwater. It is difficult to determine these elements in relation to groundwater recharge and discharge to the river, because they cannot be directly measured through site specific study. The methods of isotope mass balance combining with water budget were used to quantify the groundwater recharge from and discharge to the Heihe River, northwest China. The mean isotope ratios of monthly monitoring data for one hydrological year were selected to be the isotope rations of end members in isotope mass balance. The results from the isotope mass balance analysis, incorporating with the 35-year hydrological data, suggest that about 0.464×109 m3/a of runoff flowing out Qilian Mountains is contributed to groundwater recharge (about 28% inflow of the Heihe River), while about 1.163×109 m3/a of runoff is discharged from groundwater in the middle reach of the river, which accounts for about 46% of river runoff in the basin. The analysis offers a unique, broad scale studies and provides valuable insight into surface water-groundwater interaction in arid area.

Rain gauge spatial sparsity and temporal discontinuity of data represent one of the major issues for reliable recharge estimations. In the past decades, the use of ground-based microwave weather RaDAR has dramatically improved quantitative rainfall estimation by providing spatially continuous estimates of rainfall over an area of more than 400 km2 every 10 minutes. Furthermore, weather RaDAR data have also proved relatively reliable in mountainous areas. These paramount features of RaDAR-derived precipitation data could improve the estimation of potential recharge of aquifers, which rely on geospatializations (e.g., Thiessen polygons) of rainfall data collected by a sparse rain gauge network which often shows lacking at high altitude (i.e., recharge areas), introducing additional uncertainty in the inflow volumes. Weather RaDAR rainfall estimation is also affected by various sources of error, which can be reduced by proper post-processing; however, uncertainties remain, especially for surface rain rate estimations. Despite the currently necessary complex numerical processing, the purpose of the study is to evaluate the use of the weather RaDAR data as an alternative or in addition to meteorological data. Based on the above considerations, the feasibility of using RaDAR-based precipitation data to estimate aquifer potential recharge and calculate a detailed water budget in the areas characterized by high elevations, such as the Majella massif in the central Apennines, has been evaluated. To address this objective, the water budget has been calculated in the 2017-2018 period using both RaDAR-based precipitation data and rain gauge data, as well as adopting different methods (i.e., Turc and Thornthwaite). Although intrinsically uncertain, the RaDAR-based precipitation data provided solid results, pointed out by comparing it with water budget obtained by rain gauge data, and especially with experimental literature data. This interdisciplinary work may pave the way for continuous monitoring of aquifer potential recharge at extremely high temporal and spatial resolution.

Study region: The Upper East Region, Ghana, West Africa, lies within the Volta Basin, floods annually, and contributes substantially to Ghana’s food production. Study focus: We assessed precipitation (P), evapotranspiration (ET), and total water storage anomalies from GRACE (TWSA) and GLDAS-Noah (TWCA) to study the influence of the UER’s climate on water availability between 2002 and 2017. We analysed (1) the relative uncertainties of the data sets using the triple-cornered hat method, (2) the terrestrial water budget to validate TWSA/TWCA and (3) cross- and multi-correlation analyses to study the relationship between water storage (or availability) and meteorological variables. New hydrological insights: We found strong correlations between the different P products (r > 0.96), between the different GRACE products (r > 0.95), but not between the different ET products. The hybrid P, TWSA from the Jet Propulsion Laboratory, and ET from ERA-5 had the smallest relative uncertainties. TWSA increased by 9.8 ± 0.8 mm yr−1 while TWCA decreased. P and ET showed no evidence of a trend and were similarly influenced by the other meteorological variables. However, 93 of 183 months had water surplus and mean net P was positive – indicating the UER received more water than it lost. These agree with the increasing TWSA trend. The water budget validation also confirmed that GRACE can be used for water management; GLDAS-Noah underestimates storage in the UER.

Understanding the spatial and temporal distributions and variations of basin water budget components is essential for effective water resources management. Due to a lack of basic hydro-meteorological information, the Upper Blue Nile River Basin (UBNRB) remains poorly understood in quantifying its hydrologic fluxes and associated dynamics. This study used a physically based distributed hydrologic model, WEP. We used multi-year land use information to better estimate the water budget components (evapotranspiration, runoff and storage) of the UBNRB. WEP simulation was validated at two main sections of the Upper Blue Nile river monthly from 1992 to 2014 (23 years). Results show that the basin stores a significant amount of water during the long rainy season (June to September) due to higher precipitation and limited evapotranspiration. However, it loses this storage through evapotranspiration during the dry season (October to February). The overall basin precipitation is 1,051 mm per year. Evapotranspiration accounts for 58% of the annual water budget, runoff is 25% and storage is 18%. The findings reported in this study can shed some light on understanding the UBNRB water budget dynamics and inform water management practitioners.

Abstract Demand for lithium for batteries is growing rapidly with the global push to decarbonize energy systems. The Salar de Atacama, Chile holds ∼42% of the planet's reserves in the form of brine hosted in massive evaporite aquifers. The mining of these brines and associated freshwater use has raised concerns over the environmental responsibility of lithium extraction, yet large uncertainties remain regarding fundamental aspects of governing hydrological processes in these environments. This incomplete understanding has led to the perpetuation of misconceptions about what constitutes sustainable or renewable water use and therefore what justifies responsible allocation. We present an integrated hydrological assessment using tritium and stable oxygen, and hydrogen isotopes paired with remotely sensed and terrestrial hydroclimate data to define unique sources of water distinguished by residence time, physical characteristics, and connectivity to modern climate. Our results describe the impacts of prolonged drought on surface and groundwaters and demonstrate that nearly all inflow to the basin is composed of water recharged >65 years ago. Still, modern precipitation is critical to sustaining important wetlands around the salar. Recent large rain events have increased surface water and vegetation extents and terrestrial water storage while mining‐related water withdrawals have continued. As we show, poor conceptualizations of these complex hydrological systems have perpetuated the misallocation of water and the misattribution of impacts. These fundamental issues apply to arid regions globally. Our new framework for hydrological assessment in these basins moves beyond calculating gross inputs‐outputs at a steady state to include all compartmentalized stores that constitute “modern” budgets.

The United Nations Sustainable Development Goal (SDG) ensures adequately accessible water and management for all. Due to the rapid increase in population and industries along the Ganga river, it is necessary to estimate the water budget to fulfill the demand for water in the future. The Mann-Kendall (MK) test conducted on the Noah-Land Surface Model data for 72 years results in a maximum declining trend of water budget in the Yamuna Lower (Q = −3.82 BCM/year), and a minimum in the Damodar sub-basin (Q = −0.10 BCM/year). All the sub-basins show an increase in groundwater level (mbgl) except the Kali Sindh, which shows a decreasing trend (Q = −0.07 m/year). The percentage change was also estimated in all the sub-basins, including various parameters such as precipitation, evapotranspiration, runoff, water budget, and temperature. The extremely severe groundwater drought was estimated using the Standard Groundwater Level Index (SGWLI), from which the values for the Ram Ganga Confluence (SGWLI = 2.44; 2005), Upper stream of Gomti (SGWLI = 2.06; 2014), Ghaghra (SGWLI = 2.22; 2005), Ram Ganga (SGWLI = 2.28; 2005), Yamuna Lower (SGWLI = 2.13; 2007), Kali Sindh (SGWLI = 2.30,2.67; 2002, 2003), Chambal Upper (SGWLI = 2.30,2.20; 2001, 2003), Son (SGWLI = 2.02; 2010), Gandak (SGWLI = 2.37; 2010), Kosi (SGWLI = 2.08; 2012), Damodar (SGWLI = 2.72; 2010), and Bhagirathi (SGWLI = 2.06; 2014) were obtained for a total of 62,050 observed well data.The obtained in-situ point data is converted into the surface raster using a geostatistical technique. Our results show a declining trend in the water budget of all the 19 sub-basins of the Ganga basin and also the groundwater drought in several parts.

Abstract Irrigation is the dominant section of human water use, exerting essential impacts on hydrological processes and water resources. To more realistically simulate irrigation processes in water‐rich regions, an irrigation scheme is incorporated into a land surface‐hydrological model. It calculates the irrigation water requirement according to meteorological conditions, cropping area and growing stage, and root‐zone soil moisture, and determines the irrigation water withdrawal based on the available water resources as well as describing water extraction and irrigation processes in the model. The coupled model is applied to the Yangtze River Basin (YRB) in China, and verified using the observed daily river discharge from 1987 to 1990, evapotranspiration and irrigation amounts from 1999 to 2003. The results first show that the model can well reproduce hydrological processes within the basin, and the simulated irrigation largely agrees with the observation, in terms of annual irrigation and its spatial pattern. Second, inclusion of irrigation processes allows the model to better estimate evapotranspiration, with relative biases decreased from about −10% to −3%. It is also found that in comparison to arid/semi‐arid areas, although presenting a less effect on river discharge and groundwater, the irrigation in the YRB significantly alters hydrological processes through water redistribution. The irrigation‐induced evapotranspiration increment and runoff decrease indicate a shift in the surface water and energy balance, implying a potential effect on the atmosphere. Therefore, representing irrigation processes properly is important, particularly for understanding the coupling effect of the nature‐human system and improving the hydrological prediction accuracy.

Freshwater resources are becoming increasingly scarce in coastal areas, limiting crop productivity in coastal farmlands. Although the characteristic of crop water use is an important factor for water conservation in coastal farmlands, it has not been studied extensively. This study aimed to depict the water use process of soil–plant systems under saline stress in coastal ecosystems and optimize water management. An intensive observation experiment was performed within China’s Yellow River Delta to identify the water use processes and crop coefficients (KC) and also quantify the impacts of salt stress on crop water use. The results show that shallow groundwater did not contribute to soil water in the whole rotation; KC values for wheat–maize, wheat–sorghum, and wheat–soybean rotation systems were 45.0, 58.4, and 57% less, respectively, than the FAO values. The water use efficiency of the maize (8.70) and sorghum (9.00) in coastal farmlands was higher than that of the soybean (4.37). By identifying the critical periods of water and salt stress, this paper provides suggestions for water-saving and salinity control in coastal farmlands. Our findings can inform the sustainable development of coastal farmlands and provide new insights to cope with aspects of the global food crisis.

Turbulent momentum and heat exchanges at the air‐water interface of lakes are complex processes due to diverse characteristics such as climate, fetch limitation, and geometry; however, their parameterizations are necessary for hydro‐ and thermodynamic modeling. In this study, we performed comprehensive research on turbulent exchanges of a shallow, large but highly fetch limited lake employing 5 months of simultaneous eddy‐covariance (EC), wave, energy, and water budget measurements. Based on the Monin‐Obukhov similarity theory, wind and wave age‐related drag coefficients and roughness lengths were derived for very young wave ages. The new drag functions showed an increased water surface resistance compared to marine conditions. In terms of water vapor roughness length and transfer coefficients, an apparent intra‐seasonal variation was observed. Turbulent heat fluxes were evaluated by closing the lake's energy budget using the Bowen ratio method. Furthermore, we aimed to close the energy budget by assuring the water balance closure as well through the evaporation (latent heat flux), resulting in significant deviations from the EC‐based results. EC‐based heat fluxes and transfer coefficients were found to be underestimated on average by 29% and 33%, respectively. The water balance closure suggested that the energy residual should not be distributed based on the Bowen ratio, and sensible heat fluxes were more underestimated than latent heat fluxes. In the case of Lake Balaton, atmospheric stability plays a minor role; however, our analysis revealed significant effects caused by the surrounding topography and water side stratification. Key Points: Drag coefficient and momentum roughness length formulations are derived as a function of very young wave ages for a large but fetch limited lakeCharacteristics of turbulent air‐lake exchange processes of a shallow lake are revealed in light of energy imbalance and water budget (WB)Eddy‐covariance‐measured heat fluxes and exchange coefficients are underestimated compared to those estimated by energy budget or WB methods [ABSTRACT FROM AUTHOR]

A recent drought in Southeast Brazil affected the Cantareira reservoirs system (CRS), which supplies water to São Paulo megacity, and raised concerns on the impacts that climate change may have on the water budget at the watershed scale. We propose to identify the particular and summed contributions of key climatic variables on the variability of the water budget in Jaguari basin, the main CRS tributary, using forcing–response relationships derived from climate projections and individual elasticities of variables to temperature. Besides, we investigated whether hydrological effects of the anomalous drought were comparable to patterns simulated in the future climate. A thoroughly calibrated hydrological model for evapotranspiration (ET) and discharge (Q) was used to address our questions. We found opposite impacts in the future mostly driven by rainfall changes: under increasing (decreasing) rainfall, the mean ET increased (decreased) up to +25% (−10%) and Q increased (decreased) by +90% (−50%). Higher carbon dioxide concentrations strongly depleted the stomatal conductance, and thus the mean ET, which in turn increased the mean Q in near proportions. Major critical impacts for water management are suggested by the results. Even with a small reduction of precipitation, the discharge patterns in the drought event were replicated at similar intensities. [ABSTRACT FROM AUTHOR]

This paper is an endeavor to probe into the temporal and seasonal water-level fluctuation (WLF) of Panchet dam in India since 2005–2016 and analysis of its risk to the dam-surrounding people, using analytical hierarchy process (AHP). The present study specifies that 30% storage capacity of the reservoir has been reduced within 60 years because of rapid sedimentation, while the trend analysis indicates that 50% and 100% storage capacity will be blocked within 130 years and 250 years respectively, if the present state continues. Thus it reveals a 250 years' active life span of the dam. Average temporal WLF of the dam is 12 mts and significant at the 5% level of significance (p < 0.05) whereas, seasonal WLF is 8 mts and also significant at the 1% level of significance (p < 0.01). This temporal and seasonal WLF leads to significant rise and fall of water level that poses threat to the people of 92 villages situated within 1 km buffer area of the dam. Nine human risk alternatives (A1–A9) resulted from the WLF of the dam are identified using Delphi Questionnaire then rated and prioritized them using AHP method. Risk prioritization result varies from 9.90 to 10.29 calculated on the basis of consistency measure (CM) value. It indicates that 'Population displacement' (A3) and 'Inundation of settlement' (A2) are the highest (CM 10.29) and lowest (CM 9.90) vulnerable among the risk alternatives obtaining maximum and minimum CM values respectively. [ABSTRACT FROM AUTHOR]

Study region: The Varaždin alluvial aquifer located in the Drava River valley. Study focus: The study area is characterized by agricultural activity, which raised concerns due to the high nitrate concentration in groundwater. The present study aims to evaluate future nitrate concentrations in groundwater using the numerical groundwater flow and transport modeling. The regional model was generated in GMS software, using the MODFLOW code for steady-state groundwater flow model, and MT3DMS code for nitrate transport model. Advective-dispersive transport was simulated, without a chemical retardation process. The calibrated model was used to investigate the evolution of groundwater nitrate concentrations for the next 20 years under four scenarios: a) current nitrate input; b) zero input from wastewater; c) agricultural input reduced by 50%; d) input from natural vegetation and surface water New hydrological insights for the region: The scenario analysis demonstrated that reducing the nitrate input from agricultural areas yields a considerable reduction of nitrate in groundwater, while the impact of wastewater is negligible. Neither of the scenarios reached concentrations below threshold value of 50 mg/L for the entire aquifer in the next 20 years. The nitrate concentration in the northern part of the aquifer will remain low, mainly due to the dilution from river. The central part of the aquifer is highly dependent on changing the on-ground nitrate concentration, showing inertia regarding the nitrate attenuation in groundwater.

Abstract Clouds are a key player in the global climate system, affecting the atmospheric water and energy budgets, and they are strongly coupled to the large‐scale atmospheric circulation. Here, we examine the co‐variability of the atmospheric energy and water budget imbalances in three different global model configurations–radiative‐convective equilibrium, aqua‐planet, and global simulations with land. The gradual increase in the level of complexity of the model configuration enables an investigation of the effects of rotation, meridional temperature gradient, land‐sea contrast, and seasonal cycle on the co‐variability of the water and energy imbalances. We demonstrate how this co‐variability is linked to both the large‐scale tropical atmospheric circulation and to cloud properties. Hence, we propose a co‐variability‐based framework that connects cloud properties to the large‐scale tropical circulation and climate system and is directly linked to the top‐down constrains on the system—the water and energy budgets. In addition, we examine how the water and energy budget imbalances co‐variability depends on the temporal averaging scale, and explain its dependency on how stationary the circulation is in the different model configurations. Finally, we demonstrate the effect of an idealized global warming and convective aggregation on this co‐variability.

The scarcity of water available for landscape irrigation is a great challenge facing urban greenery and landscaping initiatives in arid and semi-arid regions. The Imam Abdulrahman bin Faisal University (IAU) has established a new campus on 3,2000,000 M2 of land extended to the eastern coast of the Arabian Gulf. Since moving to the Eastern Campus in 2014, the IAU has been working hard to increase the green spaces to minimize the environmental impact of harsh climate, hard surfaces, and building masses. In its endeavor to achieve this goal, the management of landscape plant materials and irrigation systems has not kept pace with the development of the campus. Almost 800 M3/day of irrigation water has been pumped into the system however it fails to maintain good quality landscape plants. As a result, green spaces suffer great degradation especially during hot months due to insufficient irrigation management and other factors.This study is an attempt to explore the relationship between the expansion of green spaces on the IAU’s Eastern Campus and their irrigation requirements. It applied the investigative analytical method to study and analyze the green spaces elements and their daily water budget, which led to the proposal of a synchronous management approach balancing the amount of water available for irrigation purposes and the qualities and expansion of landscape plant materials.The study found that applying the required water budget to plants since their establishment on their permanent locations is a waste of available resources, but it must be gradually increased based on the plant's size, its growth rate, and seasonal changes. However, a synchronous management approach is required to ensure that good quality landscapes are maintained while using limited available resources.

Study region: A typical grassland (Medicago sativa plot) and a typical forest land (Robinia pseudoacacia plot) located in the semi-arid Loess Plateau, China. Study focus: Field observations and scenario simulation approaches were used to investigate the potential impact of future warming and drying climate on the whole water budget and to assess whether, how, and to what degree the highly recommended man–driven tree–to–grass conversion could alleviate the adverse impact of such climate change on soil water. New hydrological insights for the region: Differences of interception and transpiration between two plots resulted in their different soil water storage. Under the warming and drying future climate, interception and transpiration in two plots would experience significant reductions, especially transpiration, and M. sativa plot could maintain more water than R. pseudoacacia plot. When R. pseudoacacia was replaced by M. sativa, although interception would dramatically increase, the transpiration would significantly decrease, which made the soil water storage experience an insignificant change. Climate change and tree–to–grass conversion mainly exerted their influences in months with larger precipitation, and vegetation conversion would reduce monthly T/ET. Our study improves the understanding of the hydrological processes under climate change and vegetation conversion, and also provides valuable guidelines for the management of water resources and the restoration of ecological environment in the semi–arid Loess Plateau.

The concept of a water balance is a foundational topic in hydrology classrooms. While understanding and applying this concept is crucial to the introduction of more advanced topics, students often struggle to develop a thorough understanding of the relationships between components, assumptions, and limitations of a water balance. To aid students in developing a working understanding of a water balance, we developed a web application that runs a one dimensional Thornthwaite-type water balance at any of thousands of NOAA climate stations across the continental United States using the local soil-water storage capacity at the station location. Within the app, students can manipulate the soil-water storage capacity, latitude, temperature, and precipitation to better understand how it works and explore scenarios of land use, extreme weather, and climate change. The application is free and will run on any device that can open an internet browser window (laptops, chromebooks, smartphones, etc). Here we present the details of the model, functionality of the application, and link to several ready-made classroom activities. Finally, results from student surveys in two hydrology classrooms show that students may learn water balance concepts more effectively than traditional methods such as spreadsheet computations.

This study assesses the detailed water budget of the Saq-Ram Aquifer System (520 000 km²) over the 2002-2019 period using satellite-gravity data from the Gravity Recovery And Climate Experiment (GRACE). The three existing GRACE solutions (JPL, CSR, GSFC) were tested for their local compatibility to compute groundwater storage variations in combination with soil moisture datasets (VIC, CLSM, NOAH) available from the Global Land Data Assimilation System (GLDAS) land surface models. Accounting for groundwater pumping (15.7 ± 1.1 mm yr-1), artificial recharge (2.2 ± 0.8 mm yr-1) and natural discharge (0.3 ± 0.06 mm yr-1) uniformly distributed over the Saq-Ram domain, the GRACE-derived water mass balance calculation yields a long-term estimate of the domain-averaged natural recharge of 2.4 ± 1.4 mm yr-1, corresponding to 4.4 ± 2.6% of the annual average rainfall. Beyond the global approach proposed here, spatial heterogeneities regarding the groundwater recharge were identified. The first source of heterogeneity is of anthropogenic origin. Within agricultural plots, irrigation excess is great enough to artificially recharge the aquifer (i.e. 167 ± 83 mm yr-1 distributed over irrigated areas). However, on the outskirts of these crop areas subjected only to the natural recharge but still influenced by pumping drawdown, there is a risk of relative disconnection from the infiltration front with the declining water table (i.e. the unsaturated zone thickens faster than percolation flows through it), making effective recharge locally zero. The second source of recharge heterogeneity identified here is natural: Volcanic lava deposits (called Harrats on the Arabian Peninsula) which cover 8% of the Saq-Ram Aquifer domain but contribute to more than 50% of the total natural recharge. Hence, in addition to this application on the Arabian Peninsula, this study strongly indicates a major control of geological context on arid aquifer recharge which has been poorly discussed hitherto. [ABSTRACT FROM AUTHOR]

Proper knowledge of potential groundwater recharge (PGR) and its spatiotemporal distribution are essential for sustainable groundwater management, especially within the context of climate change. Here, a robust GIS‐based water budget framework was developed to estimate PGR at a regional scale and map its spatial distribution. This framework is demonstrated over the Saguenay‐Lac‐Saint‐Jean region (13 200 km2) of Quebec (Canada). The PGR mapping process was based on a model incorporating water budget components. The vertical inflows (VI) include water amounts from rainfall and snowmelt, whereby the latter was assessed using HYDROTEL model. VI were combined with the maximum and minimum temperatures to estimate actual evapotranspiration (AET), while the surface runoff (RuS) was assessed using the curve number method. Field observations of annual variation in temperatures and the water budget components, over a period of 100 years (1910–2009), were used to provide a comprehensive overview of the effects of climate change on PGR. The last 10 years of the observation period (i.e., 2000–2009) indicate that 6% of the study area has PGR rates of 35%–50%. PGR rates of 20%–35% occur in 58% of the study area, while 36% have PGR of 5%–20%. The trend analysis of temperature time series reveals an average of 1.1 ± 0.6°C increase over 100 years. Also, an increase in the water budget components is observed. Despite the increasing trends of RuS and AET, PGR still showed an increasing trend with an average increase of 0.7 ± 0.4 mm/year over the past 100 years. This observation indicates that the increase in VI was enough to compensate for the increases in AET and RuS. This finding of an increasing PGR in the study area provides useful information for future studies focusing on predicting long‐term PGR evolution and for the development of efficient long‐term groundwater management strategies. [ABSTRACT FROM AUTHOR]

Lake Velence is a shallow soda lake whose water level and water quality show a severely deteriorating tendency in recent years. Until recently, the groundwater component in the lake's water budget has not been taken into consideration. To integrate the lake into the groundwater flow system at the regional scale, methods of "basin hydraulics" were applied. In addition, 17 water samples were collected for δ2H and δ18O, and for ΣU, 226Ra and 222Rn activity measurements to use these parameters as environmental tracers of groundwater contribution. Groundwater mapping revealed that groundwater recharges in Velence Hills and the local elevations south of the lake, whereas discharge occurs by the lake's shoreline and along surface watercourses. The results indicated that Lake Velence is the discharge point of local groundwater flow systems known to be more sensitive to climate changes and anthropogenic activities (e.g., contamination, overexploitation). Groundwater and lake water have similar uranium activity concentrations serving as another sign of groundwater inflow into the lake. Therefore, it is necessary to consider both the groundwater component in the lake's water management and its vulnerability regarding local and short-term changes in the catchment area. [ABSTRACT FROM AUTHOR]

Development of different strategies for sustainable water management is very important in arid region of Punjab - Pakistan having 280km2 area. In this research, water budget is estimated using the hydrologic water balance equation in Bahawalpur district in Punjab. Initially, landcover of the study area is determined using the Geographic Information System (GIS) and remote sensing. Due to excess rainfall and mostly grown crop in the study area, 4 scenarios were made, (1) 70% of sugarcane area is changed into wheat (2) 70% of sugarcane area is changed into wheat and cotton (3) 50% of sugarcane is changed into orchard (citrus) and 30% of sugarcane is changed into wheat (4) Construction of artificial ponds for storage of excess rainfall. Observed evapotranspiration is estimated using the Cropwat model, which is changed into the potential evapotranspiration for all the scenarios. Average annual rainfall in 2015 was 511.3mm in 51 events, with evapotranspiration of 4.29mm/day resulting in 366.34mm excess water. For estimation of precipitation recharge, runoff is estimated using the Hydrological Engineering Center - Hydrological Modelling System (HEC - HMS). The model was calibrated and validated for year 1996 and 1997 respectively, and runoff was estimated from 1998 to 2015. Streamflow (3L and 4L distributaries) recharge is estimated by using the average hydraulic conductivity value and interpolated on total length of distributaries. Groundwater recharge is estimated by adding precipitation recharge and stream flow recharge. Data of total number of pumping wells is taken from Agricultural Department, Punjab. Total groundwater pumpage is estimated for pumping rate of each well. Water budget for all 3 scenarios is estimated by subtracting groundwater recharge to groundwater pumpage. Actual groundwater levels were measured in the study area. Water budget is compared with the actual groundwater levels which show that our calculations are correct. Result shows that 102,575,200m3 of water can be saved annually for an area of 280km2. This study also concluded that annual average water deficit is -2.138m, -2.117m, -2.128m and -2.064m for actual condition, scenario 1, scenario 2 and scenario 3 respectively. For rainwater storage, about 7,000 artificial ponds can be constructed having capacity of 15,000m3. This water will not only cover the irrigation requirement but also decrease the threat to groundwater depletion. If these ponds are not constructed, then scenario 3 has the lowest water extraction rate and should be adopted in this region for proper water management. [ABSTRACT FROM AUTHOR]

Giant reed (Arundo donax L.), a woody grass native to the Mediterranean, has become a cause of concern for national water security in its invaded range of the arid southwestern United States, Australia, New Zealand, and South Africa. The main objective of this study was to provide the first, landscape-level estimates of water use by giant reed. The study utilized the eddy covariance method to quantify evapotranspiration (ET) throughout the 2014 and 2015 growing seasons along the Rio Grande River in Eagle Pass, Texas. We monitored ET concurrently with the implementation of a biological control program targeting giant reed. Daily ET rates were strongly associated with the phenology of giant reed, as estimated by degree day accumulation. Monthly ET was higher in each month of the active growing season (May–October) of giant reed in 2014 than in 2015. Consequently, seasonal (DOY 121-304) ET was substantially higher in 2014 (842 mm) than in 2015 (625 mm) even though the 2015 growing season was wetter. Cumulative rainfall from May to October was 188 and 264 mm in 2014 and 2015, respectively. Our study indicated that the reduction in ET could be attributed to the presence of specialist insect biological control agent, the stem-galling arundo wasp (Tetramesa romana). In 2015, we observed a 28.6% (May), 53.5% (June), and 44% (July) increase in the number of arundo wasps captured in sticky traps from the previous year. Additional studies are needed to quantify conservation and economic benefits of the biological control program in the Rio Grande Basin. [ABSTRACT FROM AUTHOR]

Defects in sanitary‐sewer infrastructure enable exchange of large volumes of fluids to and from the environment. The intrusion of rainfall and groundwater into sanitary sewers is called inflow and infiltration (I&I). Though long recognized in the assessment of sewers, the impacts of I&I on streamflow within urban watersheds are unknown. We quantified rainfall‐derived I&I (RDI&I), groundwater infiltration (GI), and total I&I using measured flows within sanitary‐sewer pipes serving four watersheds near Atlanta, Georgia, USA. Flows were monitored in pipes that parallel local stream channels and compared with streamflow measured at nearby gauging sites. Freshwater diverted into the sewer system due to I&I ranged from 24% to 36% of the flow measured within individual pipes. The RDI&I was the smaller component of I&I, ranging from 4.2 to 9.8 mm per year among watersheds. The GI was typically an order of magnitude greater than RDI&I, ranging from 24 to 41 mm per year among watersheds with annual stream discharge of approximately 500 mm. The I&I occurring at specific moments in time commonly represented 0%–20% of the flow measured in the adjacent stream. The enhancement of low flows in streams that could be achievable if I&I were abated ranges from as much as 6%–36% across watersheds. Our discussion presents explanations for the seasonality of I&I and associated impacts on streamflow in urban watersheds, while identifying important sources of remaining uncertainty. Our results support the conclusion that I&I substantially reduces flows in urban streams, especially low flows during dry weather. Plain Language Summary: Water infrastructure degrades over time, allowing for the movement of large volumes of fluids to and from the environment. Inflow is the flow of precipitation into sanitary‐sewer pipes through, for example, leaky manholes and gutter downspouts. Infiltration is the flow of groundwater into the same pipes through fractures, leaky joints, and other defects. They cause overflows of untreated sewage that endanger humans and ecosystems. Inflow and infiltration also represent large diversions of fresh water away from local streams. We examined rates of flow in four sanitary‐sewer pipes and quantified the inflow and infiltration. We compared these estimates to the rates of flow in nearby streams. We find that inflow and infiltration of fresh water into sanitary‐sewer pipes commonly represent 20%–40% of the flow in the pipes. Most of that water emanates from aquifers with a smaller fraction supplied by precipitation. If the inflow and infiltration were abated, and that fresh water instead flowed to stream channels, then the flows in those channels during dry periods could be enhanced by as much as 6%–36%. This is important in urban watersheds, where streamflow during dry weather is already diminished. Inflow and infiltration represent infrastructure‐mediated flow pathways that substantially alter the water cycle in urban watersheds. Key Points: Large volumes of precipitation and ground water flow into sanitary‐sewer pipesThis undesirable diversion of water substantially reduces flow in urban streamsAbatement of this problem could enhance low flows in urban streams by 6%–36% [ABSTRACT FROM AUTHOR]

In terrains with limited soil cover and groundwater storage, groundwater resource management is governed by the spatial nature of storage, recharge and distributed local extraction. Local soils act as important groundwater reservoirs for residents who have no other feasible water supply. A novel heuristic methodology is presented which accounts for the spatial distribution of storage and extraction, using existing topographical and geological databases in addition to well data to construct an applied conceptual groundwater model with assumed stratigraphy. The method uses a geographic information systems (GIS) environment and allows for modelling climate and land-use scenarios. Several scenarios were examined, demonstrating that average reservoir volumes meet demand but at the local levels depletion of reservoirs occurs. Groundwater abstraction in excess of 50% of the approximate freshwater storage was observed in the model, particularly near the coast. Soil-filled valleys may act as local hydraulic barriers by maintaining a higher pressure head as they are less susceptible to large-level fluctuations than the hard rock and may aid in preventing contamination from saline water provided no direct hydraulic connection is present. The method demonstrates the importance of a spatial approach in managing groundwater resources and could be used as a tool in increasing water security. HIGHLIGHTS A novel approach to a groundwater balance integrating limited storage was developed and applied to near coastal hard rock regions.; The surrogate method accounts for the spatial aspects of water extraction and storage at high-resolution and the temporal nature of groundwater recharge.; Results indicate that storage is a key factor for improving water security in coastal hard rock terrains with limited storage.; Parametric sensitivity analyses indicate that uncertainty in the storage parameter is highly spatially sensitive and dependent on the local geological conditions, in addition to likely being the most important factor in identifying sustainable groundwater extraction in hard rock coastal areas.; This novel approach could be used in groundwater resources management to identify vulnerable areas and allocate limited resources in decreasing corresponding parametric uncertainty.;

Understanding how natural processes arise from complex interactions between particular processes at small spatiotemporal scales and in turn how these processes form patterns at large spatiotemporal scales is one of the current principal questions in environmental science. The problem is very complicated, as in many cases, key processes are often studied by researchers in separate disciplines such as ecology, soil science or hydrology. One of the major obstacles is that the processes at a landscape scale are difficult to manipulate and, in many cases, even measure. In particular, the belowground processes are in many cases overlooked or at least understudied. Here we briefly describe a methodological solution used to cope with this problem and describe artificial catchments designed for experimental manipulation at the level of a landscape, called FALCON. This array has two treatments: one mimics a site reclaimed using an alder plantation and the other was left to unassisted primary succession. For each treatment, there were two replicates in four similar catchments. Individual catchments are hydrologically isolated from the environment and equipped with instruments, so that all the main processes and all significant flows of substances and energy in the ecosystem can be monitored, including the cycling of water, nutrients and gas between the ecosystem and the atmosphere. In addition, in each catchment there are sets of lysimeters, which allow the study of small-scale processes and how these can be extrapolated to the catchment scale. In addition, two lysimetric fields exist alongside the catchments for monitoring the effects of the experimental manipulation.

Wetland acts as a biological supermarket and helps to determine people's lives, livelihoods and needs. In third world countries like India, wetlands are suppressed by over populated surroundings. Although the size, volume and depth of wetlands change due to the whims of the weather, and water pollution and sedimentation are caused by various human activities, people still use wetlands as a means of rice and fish production. This article discusses the continuous decaying of wetlands in the floodplain region of the Bhagirathi–Hooghly river and its impact on human dependency on wetlands. The location of the continuous siltation of the wetlands is known with the help of bathymetry which proves that the wetlands are getting more and more decayed. Agricultural runoff and sewerage from adjacent farmland also continue to pollute the wetlands' environment, with high levels of TDS (total dissolved solids) and Cl2+ (chloride). The result shows that rice and fish production in these decayed wetlands is continuously increasing with seasonal water budget scenario. Comparing economic production with water budgets through SK (seasonal Kendall) test and ARMA (autoregressive moving average process), trend analysis shows the growing demand of the people has made the position of the wetlands miserable, but the economic aspect of the people has benefited. Dredging, public awareness, water pollution prevention and sustainable use of wetlands can be considered as the only way to restore the decayed wetlands to their glory. [ABSTRACT FROM AUTHOR]

To investigate the response of vegetation dynamics and surface water budget to climate change on a basin scale, the biophysical/dynamic vegetation model SSiB4/TRIFFID was coupled with TOPMODEL (hereinafter referred to as SSiB4T/TRIFFID). The effects of the integration on hydrological simulations were examined and long‐term dynamic simulations of vegetation succession and the water–carbon balance were performed under different climate scenarios for a subalpine basin of southwestern China using SSiB4T/TRIFFID. The coupled model SSiB4T/TRIFFID produces higher soil wetness and evapotranspiration, lower total run‐off and more realistic partitioning of discharges between surface run‐off and base flow. All long‐term simulations for the subalpine basin show that the fraction of vegetation changes from a dominance of C3 grasses to tundra shrubs and then to forests. Annual evapotranspiration in the control run is 388.5 mm year−1 (dominance of C3 grasses), 445.3 mm year−1 (dominance of tundra shrubs) and 388.1 mm year−1 (dominance of forests). Under an increase in temperature by 5°C and in precipitation by 40%, the evapotranspiration of forests is the highest among the three vegetation types. In the humid region, Forest evapotranspiration increases the most with increases in temperature, which results in the role of forests in increasing run‐off changing to having no significant effect on run‐off, and then to reducing run‐off. In regions with water limitation, forest evapotranspiration increases the most as precipitation increases. The effect of forests in reducing run‐off increases with increased precipitation. The spatial variation in the climate exerts an important impact on spatial changes in forest–run‐off relationships. [ABSTRACT FROM AUTHOR]

One of the main factors for the urban sustainable development planning is the fresh water availability, especially in arid area such as Holy Makkah, Saudi Arabia. The area has most important religious places for the Islamic world, and thus, millions of visitors are coming to the city every year. Almost half of fresh water demands in the area are coming from the decreasing groundwater that are embodied in the wadi deposits and fractured crystalline rocks. However, the fresh water demands are rapidly increasing; therefore, the evaluation of the water resources along the area is strongly needed. Integrated geophysical methods to evaluate the subsurface situation and water content have been applied along Wadi Nu'man that is bounding the Holy area. Aeromagnetic and geoelectrical resistivity sounding measurements have been carried out along the wadi. Processing and modeling of the magnetic data indicated that the depth to the basement is irregular and controlled by the subsurface structure elements and the basement topography. The subsurface basement relief model indicated two local basins that undergo to keep the precipitated rainfall. Moreover, processing a suite of 155 vertical electrical soundings (VES) has been carried out along the wadi to determine the varying alluvial thickness covering the subsurface basement and the degree of water saturation. The processing and interpretation of VES data had been controlled by the subsurface lithological information of the available borehole as well as the magnetic data interpretation. Based on the output interpreted models, 2D cross sections have been constructed to emphasize the alluvial wadi deposits and the basement. Finally, the water budget along the wadi has been estimated using the results of geophysical and available metrological data sets. The estimated water stored in the subsurface wadi deposits and shallow fracture basement is around 56 million m3. [ABSTRACT FROM AUTHOR]

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Endothermic organisms typically maintain high and relatively constant body temperatures in the face of environmental variation by regulating their metabolic and water loss rates in conjunction with behavioural and postural adjustments. A mechanistic understanding of these processes provides a perspective of the fundamental niches of endotherms by quantifying their energy and water requirements, restrictions on habitat use and survival limits. Here we introduce and document the endotherm model of NicheMapR, an R package that includes a suite of programs for the mechanistic modelling of energy and mass exchange between organisms and their environments. The NicheMapR endotherm model is based on a Fortran program that simultaneously solves for the metabolic rate, water loss rate, fur/feather temperature and skin temperature required to balance the heat budget in a given microclimate. These calculations are a function of traits relating to insulation, shape, physiological and behavioural responses. The program contains algorithms for computing heat transfer through a porous insulative layer (fur/feathers), including solar and infrared radiation fluxes as well as convective and conductive exchange, and can handle differing dorsal and ventral traits and environments. Here we configure the program to be called from R as part of the NicheMapR package and describe the model in detail. We break the program into a set of modules that can be run in isolation, or jointly, and combined in different ways to capture species‐specific thermoregulatory responses. We explain the theory and underlying subroutines, and the default thermoregulatory settings. We discuss how the model can be adapted to incorporate species‐specific behaviours and extended to incorporate multiple body parts. We also compare the endotherm modelling setup with the ectotherm model of the NicheMapR package and discuss how the different modelling strategies they require reflect fundamental biological issues. [ABSTRACT FROM AUTHOR]

Copyright of Vatten is the property of Foreningen Vatten and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This data note introduces a database of long‐term daily total precipitation and stream discharge data for seven forested watersheds in Japan that have been continuously monitored by the Forestry and Forest Products Research Institute. Three of the watersheds started data collection in the 1930s. Forest cover across the sites ranges from cool to warm temperate regions with the latitude spanning from 31 to 44° N and annual precipitation ranging from 1200 to 3000 mm yr−1. The effects of vegetation change via clearcutting, thinning and forest fire (among other stressors) on stream discharge can be analysed from the long‐term observation sites. Moreover, this multi‐site dataset allows for inter‐ and intra‐site comparisons of annual water loss (difference of annual precipitation and stream discharge). These long‐term datasets can provide comprehensive insights into the effects of climate change and other stressors on forested ecosystems, not only in Japan but across a spectrum of forest types, if combined with other long‐term records from other forested watersheds across the world. [ABSTRACT FROM AUTHOR]