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Abstract Background Projecting future streamflow variation or the hydrological impact of climate change plays a pivotal role in the sustainable implication of planning water resources management. Therefore, this study predicts the potential of climate change’s impact on hydrological components in the Upper Awash Basin (UAB). The study applied a statistical downscaling model (SDSM) to generate future high-resolution climate data from the climate model output of the Canadian Second Generation Earth System Model (CanESM2) and the National Centers for Environmental Prediction (NCEP) under the representative concentration pathways (RCP4.5 and RCP8.5) scenarios. To analyze the trend of future rainfall and temperature, non-parametric Mann-Kendall, Modified Mann-Kendall tests, Sen’s slope estimator, and changing point (Pettit) tests were used. The output of downscaled climate data is used as input to a calibrated and validated Soil and Water Assessment Tool (QSWAT) model to assess the impact of future climate change on UAB hydrology. Results The results show that annual rainfall and temperature are significantly increased (p

Understanding the effects of groundwater withdrawal on streamflow depletion is important for effectively managing water resources. The Soil and Water Assessment Tool (SWAT) model has a groundwater module to calculate the groundwater budget and groundwater discharge. However, the water pumped from the aquifer is not considered in the SWAT module that estimates groundwater discharge. Therefore, this module was modified to consider the impact of groundwater pumping on the changes in groundwater discharge in the Bokhacheon watershed, South Korea. The model's water transfer module was improved to allow water from the aquifer to be transferred to destination locations, such as residential, industrial, and agricultural lands. Using the modified SWAT, streamflow responses to groundwater extraction were simulated for 2011–2019. The groundwater withdrawal induced decreases of 14.6 and 24.2% in low and drought flows, respectively, at the watershed's outlet. The groundwater withdrawals decreased groundwater flow and total water yield by 23.5% and 9.8%, respectively, and increased surface flow, lateral flow, percolation, soil water, and evapotranspiration owing to the increased soil moisture resulting from the partial re-infiltration of the groundwater pumped for agricultural irrigation. The modified SWAT can effectively estimate streamflow depletion resulting from groundwater pumping without extensive hydrogeological input data and computational time. [ABSTRACT FROM AUTHOR]

Background: Projecting future streamflow variation or the hydrological impact of climate change plays a pivotal role in the sustainable implication of planning water resources management. Therefore, this study predicts the potential of climate change's impact on hydrological components in the Upper Awash Basin (UAB). The study applied a statistical downscaling model (SDSM) to generate future high-resolution climate data from the climate model output of the Canadian Second Generation Earth System Model (CanESM2) and the National Centers for Environmental Prediction (NCEP) under the representative concentration pathways (RCP4.5 and RCP8.5) scenarios. To analyze the trend of future rainfall and temperature, non-parametric Mann-Kendall, Modified Mann-Kendall tests, Sen's slope estimator, and changing point (Pettit) tests were used. The output of downscaled climate data is used as input to a calibrated and validated Soil and Water Assessment Tool (QSWAT) model to assess the impact of future climate change on UAB hydrology. Results: The results show that annual rainfall and temperature are significantly increased (p < 0.05) in the UAB under RCP4.5 and 8.5 for the model ensemble mean for both short- and long-term scenarios. The change in the rainfall, the maximum and minimum temperature is mostly visible in the second period (the 2060s). Climate change is likely to cause persistent decreases in surface runoff (SUR_Q) and increases in actual evapotranspiration (ET) under all climate scenarios in the three periods. Reduction in SUR_Q despite an increase in rainfall could be due to an increment in both temperature and ET. The study also identified inconsistent seasonal changes in projected future precipitation that considerably impact overall climatic conditions. Conclusions: This research is essential to develop an interdisciplinary approach that integrates environmental policies for the coherent use and management of water resources for future climate change and ecological protection in the basin, including other similar basins. [ABSTRACT FROM AUTHOR]

Water balance as a technique is considered one of the means that is relied upon in solving significant hydrological problems. The soil and water assessment tool (SWAT) model was used in this study to assess the water balance in the Wadi Al- Mohammadi basin located at the eastern edge of the Western Desert. Digital elevation model, soil data, Land use - Land cover, and climate data represent the most important requirements for the SWAT model's input as a database. The Wadi Al-Mohammadi basin delineation results show the overall drainage area was 2286.8 km² with seven sub-basins. The trend line of climate data indicates a clear increase in the total rainfall, relative humidity, temperature, and solar radiation from 1990-2020, while the wind speed decreased during the observed period. The average monthly hydrological components (precipitation, actual evapotranspiration, surface runoff, lateral flow, and deep aquifer recharge) representing the basin's water balance are 68.8 mm, 67 mm, 2.03 mm, 0.02 mm, and 0 mm, respectively. [ABSTRACT FROM AUTHOR]

The key aim of this review was to consolidate the latest information on the regularly used and newly developed hydrological models that may be supportive in choosing the best-suited model for specific research applications in hydrological studies. The paper briefly discusses various models available for the simulation of specific processes in the hydrological cycle. The models presented in this paper are classified based on distributed, semi-distributed, stochastic, and process-based deterministic approaches. These models are employed for research applications in sedimentation analysis, sub-surface modeling, hydraulic routing, and hydrological prediction. Criteria used for assessing models are hydrological components that the model can simulate, the leading equations used to simulate the hydrologic components, requirements of the minimum data necessary to run the model, and the spatiotemporal scale of the model. These are the basic requirements that must always be addressed before selecting any model for future use. [ABSTRACT FROM AUTHOR]

Understanding how watersheds respond to ecological changes and how LULC alteration affects watershed hydrology is crucial for water and soil resource management. LULC changes in the Ajora-Woybo watershed, Ethiopia, have momentously affected the water and soil resources. The researchers aimed to see how LULC changes affect hydrological components (HCs) and sediment yield (SED) in the watershed, both historically and in the future. The Soil and Water Assessment Tool (SWAT2012) and Partial Least Squares Regression (PLSR) models were used to investigate the contribution of each of the LULC classes to achieve the goal. The findings revealed a continual growth of cultivated land, built-up areas, and bare land, and a retreat of shrub land and forest land during the 2000 to 2020 periods, which is expected to continue in the 2035 and 2050 periods. Changes in LULC that happened over the historical era increased yearly surface runoff (23.5%), water yield (5.7%), and sediment yield (23.5%). On the other hand, the observed modifications have reduced lateral flow (12.8%) and groundwater flow (10.9%). Except for the 2020 LULC period, evapotranspiration decreased during the studied years. The future impacts of LULC states are predicted to increase in line with the historical trend. The PLSR results showed that cultivated land and built-up areas had a positive association with surface runoff and sediment yield, but shrub land and forest land had a negative correlation. This highlights the importance of controlling the LULC change as soon as possible to maintain long-term watershed stability. [ABSTRACT FROM AUTHOR]

The Qinghai-Tibetan Plateau (QTP) is one of the amplifiers of global climate change. The headwater area of the Yellow River Basin (HYRB) on the QTP is the dominant water source region for the whole Yellow River Basin. However, the sensitive responses of hydrological processes to the intensifying climate change are exerting high uncertainties to the water cycle in the HYRB. The aim of this study was to investigate the potential climate change under three Representative Concentration Pathways (RCP 2.6, 4.5, and 8.5) and their hydrological impacts in this region using the ensemble climate data from eight general circulation models (GCMs) and the Soil and Water Assessment Tool (SWAT). Compared to the baseline (1976–2015), the projected climate indicated a rise of 7.3–7.8% in annual precipitation, 1.3–1.9 °C in maximum air temperature, and 1.2–1.8 °C in minimum air temperature during the near future period (2020–2059), and an increment of 9.0–17.9%, 1.5–4.5 °C, and 1.3–4.5 °C in precipitation, maximum and minimum temperature, respectively, during the far future period (2060–2099). The well-simulated SWAT modeling results suggested that due to a wetter and warmer climate, annual average actual evapotranspiration (AET) would increase obviously in the future (31.9–35.3% during the near future and 33.5–54.3% during the far future), which might cause a slight decrease in soil water. Water yield would decrease by 16.5–20.1% during the near future period, implying a worsening water crisis in the future. Till the end of this century, driven by the increased precipitation, water yield would no longer continue to decrease, with a decline by 15–19.5%. Overall, this study can not only provide scientific understanding of the hydrological responses to the future climate in both semi-arid and alpine areas, but also contribute to the decision support for sustainable development of water resources and protection of eco-environment in the HYRB. [ABSTRACT FROM AUTHOR]

Periodic flooding in floodplain wetlands dominates the landscape pattern, creating rich and diverse habitats for waterbirds. However, most studies on floodplain wetland landscape are conducted at interannual scale, while few researches investigate the effect of short‐term changes of hydrological components, such as maximum continuous flooding day, average flooding depth, maximum continuous drought day, and distance from water body. This study developed an effective approach by integrating a two‐dimensional hydrodynamic model and a geographic detector model to investigate the single and interactive effects of short‐term hydrological components on the landscape pattern of waterbird habitat in floodplain wetlands. The developed approach was demonstrated in the Poyang Lake in Jiangxi province of China, an important conservation floodplain wetland in the Ramsar Convention. We found the short‐term hydrological components could impose a significant impact on the landscape pattern of waterbird habitat. Particularly, the interactive effects of multiple hydrological components were stronger than that of a single component, showing nonlinear enhancement. The developed approach could provide a viable way to study the ecological impacts of short‐term hydrological components on the landscape pattern of waterbird habitat in floodplain wetlands, thus offer scientific references for waterbird habitat management in floodplain wetlands. Key Points: The short‐term hydrological components were used to characterize the landscape pattern of waterbird habitats in floodplain wetlandThe maximum continuous flooding day at monthly scale could impose significant impacts on the landscape pattern of meadowThe interactive effects of multiple hydrological components were stronger than that of a single component [ABSTRACT FROM AUTHOR]

Quantifying the influences of land use/cover (LULC) change on hydrological processes is important for rational utilization of water resources. The objective of this study was to evaluate the impacts of spatiotemporal LULC change on hydrological components in a typical agricultural area located in the North China Plain at both basin and sub-basin scales. LULC change was quantified, and the Soil and Water Assessment Tool was optimized using parameters associated with LULC conditions. We concluded that the urban and forest areas increased by 25.57 and 10.56%, with the cropland area decreased by 36.76%. About half of the surface runoff (SURQ) in the basin was generated from the urban area, with the SURQ increased significantly in the upstream and downstream of the basin where overlapped with urbanized areas. The proportions of evapotranspiration generated by cropland and forest areas increased slightly (0.89 and 0.55%, respectively), especially in sub-basins where the conversion of cropland to forest was obvious. Urban, forest, and cropland were the main types that generated water yield (WYLD). The proportion of WYLD generated on the urban area increased by 9.55% and decreased in other areas, which may be related to the combined effects of urbanization and forest reduction. Highlights The SWAT model was used under different scenarios for a typical agricultural area, North China Plain.; The influences of land use/cover change on key hydrological components were analyzed at both basin and sub-basin scales.; Urbanization and reforestation will affect changes in hydrological components.;

Climate change has pronounced impacts on water resources, especially in arid regions. This study aims at assessing the impacts of climate change on streamflow of the Wadi Halilrood Basin which feeds the Jazmorian wetland in southeastern Iran. To simulate streamflow and hydrological components in the future periods (2030–2059 and 2070–2099), projections for the emission scenarios RCP4.5 and RCP8.5 from 11 global-regional climate models and two bias correction methods are used as input data for a hydrologic model that represents the daily streamflow with good accuracy (NSE: 0.76, PBIAS: 4.7, KGE: 0.87). The results indicate a slight increase of streamflow in January and March, due to the higher intensity of precipitation. However, according to the predicted flow duration curves, a decrease for high and very high flow and no remarkable changes for middle, low and very low flow is found under both emission scenarios for both future periods. Compared to the simulated hydrological components for the baseline, a slight increase of evapotranspiration of around 6 mm (4%) and 2 mm (

The objective of this study is to assess the impacts of Land Use Land Cover change on the hydrological responses of the Mahanadi river basin, a large river basin in India. Commonly, such assessments are accomplished by using distributed hydrological models in conjunction with different land use scenarios. However, these models through their complex interactions among the model parameters to generate hydrological processes, can introduce significant uncertainties to the hydrological projections. Therefore, we seek to further understand the uncertainties associated with model parameterization in those simulated hydrological responses due to different land cover scenarios. We performed a sensitivity-guided model calibration of a physically semi-distributed model, the Variable Infiltration Capacity (VIC) within a Monte Carlo Framework to generate behavioural models for subcatchments of the Mahanadi river basin. These behavioural models are then used in conjunction with historical and future land cover scenarios from the recently released, Land use Harmonisation (LUH2) to generate hydrological predictions and related uncertainties from behavioural model parameterisation. The LUH2 dataset indicates a noticeable increase in the cropland (23.3% cover) at the expense of forest (22.65% cover) by the end of year 2100 compared to the baseline year, 2005. As a response, simulation results indicate a median percent increase in the extreme flows (defined as the 95th percentile or higher river flow magnitude) and mean annual flows in the range of 1.8 to 11.3% across the subcatchments. The direct conversion of forested areas to agriculture (on the order of 30,000 km²) reduces the Leaf Area Index and which subsequently reduces the Evapotranspiration (ET) and increases surface runoff. Further, the range of behavioural hydrological predictions indicated variation in the magnitudes of extreme flows simulated for the different land cover scenarios, for instance uncertainty in far future scenario ranges from 17 to 210 cumecs across subcatchments. This study indicates that the recurrent flood events occurring in the Mahanadi river basin might be influenced by the changes in LULC at the catchment scale and suggests that model parameterisation represents an uncertainty, which should be accounted for in the land-use change impact assessment. [ABSTRACT FROM AUTHOR]

The impact of anthropogenic activities in major river watersheds leading to alterations in the environment has triggered this study within the Ashi watershed of northeast China. Understanding individual land use/land cover (LULC) change contribution to watershed hydrology is vital for water resource planning, utilization of land resources and sustaining hydrological balance. This research investigates the influence of LULC alteration on the hydrology of the watershed from 1990 to 2014 and predicts LULC impacts on the hydrological components under different scenarios in 2030. Combined approach for Landsat images classification; Cellular-Automated (CA-Markov) for prediction and Soil and Water Assessment Tool were used. Partial least square regression (PLSR) model was applied to quantify the contribution of each LULC on hydrology. The results show that urban, water, agriculture, open canopy and other vegetation experienced an increment from 1990 to 2014. The predicted LULC for 2030 based on worst-case scenarios indicates urbanization and agriculture increase, while best-case scenario indicates a controlled expansion trend of urban and agriculture and regeneration of closed canopy. The changes in LULC increase stream flow (11.5%), surface runoff (86.6%), water yield (10.5%) but reduce lateral flow (64.9%), groundwater (27.9%) and ET (1%). Stream flow, water yield, surface runoff, lateral flow and evapotranspiration are expected to further increase under both scenarios, increasing more in the worst-case scenario. Urban, agriculture and close forest contributed in determining hydrological processes and are therefore chief environmental stressors in the Ashi watershed. This recommends regulating urban sprawl and agricultural activities to maintain hydrological balance. [ABSTRACT FROM AUTHOR]

Land-use/land-cover (LULC) changes in the Gidabo basin, Rift Valley, Ethiopia, have greatly affected the hydrology of the basin. This study integrates hydrological modelling with statistical analysis to evaluate the hydrological response of LULC changes during the period 1988–2018. Using the Soil and Water Assessment Tool (SWAT) and partial least squares regression (PLSR) models, the influences of individual LULC changes on different components of the hydrological cycle are assessed. The results of the Mann-Kendall test showed no significant trends in annual rainfall over the basin at the 95% significance level. Change in LULC resulted in an increase in annual mean surface runoff by 23.6 mm during the period 1988–2018. Meanwhile, the annual mean baseflow, lateral flow, percolation and evapotranspiration (ET) were reduced by 9.1, 4.2, 10.2 and 12.2 mm, respectively. PLSR analysis indicated that cultivated land affected the lateral flow and ET negatively in contrast to agroforestry and grassland, which had a positive influence. [ABSTRACT FROM AUTHOR]

The Chongwe River Catchment (CRC) is located in Zambia. It receives a mean annual precipitation of 889 mm. The catchment is facing growing anthropogenic and socio-economic activities leading to severe water shortages in recent years, particularly from July to October. The objective of this study was to assess the available water resources by investigating the important hydrological components and estimating the catchment water balance using the Water Evaluation and Planning (WEAP) model. The average precipitation over a 52 year period and a 34 year period of streamflow measurement data for four stations were used in the hydrological balance model. The results revealed that the catchment received an estimated mean annual precipitation of 4603.12 Mm3 . It also released an estimated mean annual runoff and evapotranspiration of 321.94 Mm3 and 4063.69 Mm3 , respectively. The estimated mean annual total abstractions in the catchment was 119.87 Mm3 . The average annual change in the catchment storage was 120.18 Mm3 . The study also determined an external inflow of 22.55 Mm3 from the Kafue River catchment. The simulated mean monthly streamflow at the outlet of the CRC was 10.32 m3 /s. The estimated minimum and maximum streamflow volume of the Chongwe River was about 1.01 Mm3 in September and 79.7 Mm3 in February, respectively. The performance of the WEAP model simulation was assessed statistically using the coefficient of determination (R2 = 0.97) and the Nash–Sutcliffe model efficiency coefficient (NSE = 0.64). The R2 and NSE values indicated a satisfactory model fit and result. Meeting the water demand of the growing population and associated socio-economic development activities in the CRC is possible but requires appropriate water resource management options. [ABSTRACT FROM AUTHOR]

It is critically important to quantify the impact of land use land cover (LULC) changes on hydrology, and to understand the mechanism by which LULC changes affect the hydrological process in a river basin. To accurately simulate the hydrological process for a watershed like the Wei River Basin, where the surface characteristics are highly modified by human activities, we present an alternative approach of time-varying parameters in a hydrological model to reflect the changes in underlying land surfaces. The spatiotemporal impacts of LULC changes on watershed streamflow are quantified, and the mechanism that connects the changes in runoff generation and streamflow with LULC is explored. Results indicate the following: (1) time-varying parameters' calibration is effective to ensure model validity when dealing with significant changes in underlying land surfaces; (2) LULC changes have significant impacts on the watershed streamflow, especially on the streamflow during the dry season; (3) the expansion of cropland is the major contributor to the reduction of surface water, causing decline in annual and dry seasonal streamflow. However, the shrinkage of woodland is the main driving force that decreases the soil water, thus contributing to a small increase in streamflow during the dry season. [ABSTRACT FROM AUTHOR]

Forests have had a vital role in survival, growth and development of human communities in various epochs of history. Overexploitation of the forest resources induced environmental disturbance leading to desertification and disappearance of civilizations. Deforestation has detrimental effects on the watershed environment which resulted in increasing flooding and sediment yield. Since long time ago, many studies have been conducted to evaluate the effects of managerial and engineering treatments on forest ecosystems characteristics. Since the hydrologic response of forest disturbance has been rarely considered, the present study has been conducted to investigate the effect of forest disturbance on hydrological components in sample plot scale with three replicates in the northern forests ofIranduring seventeen storm events occurred from October 2009 to April 2010. The rain depth was measured by using a rain gauge installed in the study area. The runoff volume and sediment yield were also measured through field data collection and lab analyses by weighting and decantation methods. The results of the study showed significant effects of forest degradation (P

The Adige River flows from the Eastern Alps to the Adriatic Sea and the understanding of its fluvial dynamics can be improved by geochemical and O-H isotopic investigation. The most negative isotopic compositions are recorded close to the source (δO between −14.1 and −13.8 ‰, δD between −100.3 and −97.0 ‰), and δD and δO values generally increase downstream through the upper part (UP, the mountainous sector), stabilizing along the lower part (LP, the alluvial plain) of the river with δO between −12.4 and −11.8 ‰, δD between −86.9 and −83.7 ‰. The isotopic variations along the stream path (δO-δD vs distance from the source) depict subparallel distributions for all the investigated periods, with less negative values recorded in winter. Total dissolved solids (TDS) concentration shows the lowest value (<100 mg/l) at the river source, jumping to 310 mg/l at the Rio Ram inflow, then decreasing down to the Isarco River confluence; from here, we observed an increase toward the river mouth, with different values in the distinct sampling periods. The lowest values (140-170 mg/l) were recorded during high discharge in spring, whereas higher TDS values (up to 250 mg/l) were recorded during winter low flow conditions. Extreme TDS values were observed in the estuarine samples (up to 450 mg/l), as result of mixing with seawater. The results allow for the identification of distinct water end-members: glacio-nival component(s) characterized by the most negative isotopic composition and extremely low TDS, a rainfall component characterized by intermediate isotopic and elemental composition and groundwater characterized by the less negative isotopic composition and comparatively higher TDS. An additional component is represented by seawater, which is recorded at the lowest reach of the river during drought periods. These contributions variously mix along the stream path in the distinct hydrological periods, and the presented data are a snapshot of the current hydroclimatic conditions. Future investigations will evaluate possible hydrological variations related to meteo-climatic changes. Monitoring is fundamental for future water management to overcome the vanishing of a significant water end-member of the basin, i.e., the glacio-nival reservoir that is severely affected by the ongoing climatic changes. [ABSTRACT FROM AUTHOR]

The article presents a study which examines the integrated effects of topography and soil properties on runoffs occurred in two wooded catchments in Dongjiang Basin of South China. The study applied the modified TOPMODEL for stimulating the runoff-generating processes and separating runoff elements. The results of the study showed that the total runoff increased by 6.6% due to the 50% decrease in effective storage capacity over the soil zones.

The hydrological cycle of the Arctic river basin holds an important position in the Earth's system, which has been significantly disturbed by global warming. This study analyzed recent changes in the hydrological components of two representative Arctic river basins in Siberia and North America, the Lena River Basin (LRB) and Mackenzie River Basin (MRB), respectively. The trends were diagnosed in hydrological components through a comparative analysis and estimations based on remote sensing and observational datasets during 2003–2016. The results showed that the annual precipitation decreased at rates of 1.9 mm/10a and 18.8 mm/10a in the MRB and LRB, respectively. In contrast, evapotranspiration (ET) showed increasing trends, with rates of 9.5 mm/10a and 6.3 mm/10a in the MRB and LRB, respectively. Terrestrial water storage (TWS) was obviously decreased, with rates of 30.3 mm/a and 18.9 mm/a in the MRB and LRB, respectively, which indicated that more freshwater was released. Contradictive trends of the runoffs were found in the two basins, which were increased in the LRB and decreased in the MRB, due to the contributions of the surface water and base flow. In addition, the mean annual cycles of precipitation, ET, TWS, runoff depth, surface flow and base flow behaved differently in both magnitudes and distributions in the LRB and MRB, the trends of which will likely continue with the pronounced warming climate. The current case studies can help to understand the recent changes in the Arctic hydro-climatology and the consequence of global warming in Arctic river basins. [ABSTRACT FROM AUTHOR]

Effective information regarding environmental responses to future land-use and climate change scenarios provides useful support for decision making in land use planning, management and policies. This study developed an approach for modeling and examining the impacts of future land-use and climate change scenarios on streamflow, surface runoff and groundwater discharge using an empirical land-use change model, a watershed hydrological model based on various land use policies and climate change scenarios in an urbanizing watershed in Taiwan. The results of the study indicated that various demand and conversion policies had different levels of impact on hydrological components in all land-use scenarios in the study watershed. Climate changes were projected to have a greater impact in increasing surface runoff and reducing groundwater discharge than are land use changes. Additionally, the spatial distributions of land-use changes also influenced hydrological processes in both downstream and upstream areas, particularly in the downstream watershed. The impacts on hydrological components when considering both land use and climate changes exceeded those when only considering land use changes or climate changes, particularly on surface runoff and groundwater discharge. However, the proposed approach provided a useful source of information for assessing the responses of land use and hydrological processes to future land use and climate changes. [ABSTRACT FROM AUTHOR]

Damming effect on demarcating fish habitability of some selected fishes in wetland based on image driven hydrological components like water presence frequency, water depth and hydro-period is the major focus of this present study. From the study, it is found that damming has hastened the rate of hydrological transformation increasing inconsistency in water presence frequency, reducing the depth of water and shortening hydro-period of the wetland. Integrated Rule Based Decision Tree (RBDT) modeling incorporating the above mentioned hydrological components has been used for finding out suitable habitat for some selected fishes (carp fishes, shrimp, tilapia and cat fishes) for both pre and post-dam periods. From these models, it is evident that a very small proportion of wetland area was suitable for good fish habitat (11.03% to 48.43%) during pre-dam period, however, post-dam hydrological alteration has almost deteriorated the good habitat area. Field investigation has proved that fish catch frequency, growth rate of fish were high earlier but it is significantly reduced during post-dam period. Such image driven hydrological component based fish habitat modeling is very new, however inclusion of more factors like water quality and food availability may enhance the quality of output. • Integration of hydrological components was done to analyze habitat suitability for fishing. • Wetland area was reduced by 82.53 km2 to 36.14 km2. • 27.93% of area has converted from high to low WPF zone. • 51.59% to 100% of wetland area was converted to poor habitat condition. [ABSTRACT FROM AUTHOR]

Changes in hydrological cycles and water resources will certainly be a direct consequence of climate change, making the forecast of hydrological components essential for water resource assessment and management. This research was thus carried out to estimate water balance components and water yield under current and future climate change scenarios and trends in the Guder Catchment of the Upper Blue Nile, Ethiopia, using the soil and water assessment tool (SWAT). Hydrological modeling was efficaciously calibrated and validated using the SUFI-2 algorithm of the SWAT model. The results showed that water yield varied from 926 mm to 1340 mm per year (1986–2016). Regional climate model (RCM) data showed, under representative concentration pathways (RCP 8.5), that the precipitation will decrease by up to 14.4% relative to the baseline (1986–2016) precipitation of 1228 mm/year, while the air temperature will rise under RCP 8.5 by +4.4 °C in the period from 2057 to 2086, possibly reducing the future basin water yield output, suggesting that the RCP 8.5 prediction will be warmer than RCP 4.5. Under RCP 8.5, the total water yield from 2024 to 2086 may be reduced by 3.2 mm per year, and a significant trend was observed. Local government agencies can arrange projects to solve community water-related issues based on these findings. [ABSTRACT FROM AUTHOR]

Chongwe River Catchment, a sub-catchment of the Zambezi River Basin, has been experiencing changes in land use/land cover (LULC) and in its hydrology. This study aims to assess the impact of LULC changes on the catchment's hydrological components such as streamflow, evapotranspiration and water abstractions. LULC change data, detected from the 1984, 1994, 2014 and 2017 USGS Landsat imagery using a maximum likelihood supervised classifier, were integrated into the WEAP Model along with soil, slope and hydro–climate data. The results showed that between 1984 and 2017 built-up area increased by 382.77% at 6.97 km2/year, irrigated agriculture increased by 745.62% at 1.70 km2/year, rainfed farms/ranch/grassland increased by 14.67% at 14.53 km2/year, forest land decreased by 41.11% at 22.33 km2/year and waterbodies decreased by 73.95% at 0.87 km2/year. Streamflow increased at a rate of 0.13 Mm3 per annum in the wet seasons and showed a high variation with flow volume of 79.68 Mm3 in February and 1.01 Mm3 in September. Annual actual evapotranspiration decreased from 840.6 mm to 796.3 mm while annual water abstraction increased from 8.94 mm to 23.2 mm from the year 1984 to 2017. The pattern of LULC change between 1984 and 2017 has negatively impacted the hydrology of the Chongwe River Catchment. From these findings, an integrated catchment management and protection approach is proposed to mitigate the negative impacts of LULC dynamics on hydrological components in the Chongwe River Catchment. [ABSTRACT FROM AUTHOR]

With increased attention paid to the changes of global climate, the impacts on hydrological processes remain poorly understood in specific basins. In this study, we selected Luanhe River Basin, which is an important source of water supply to Beijing and Hebei, as a case study for the analysis of the combined impact of precipitation and temperature change to hydrological components in a semi-arid river basin. This study investigated the change of the blue water flow (BWF), green water flow (GWF), and green water storage (GWS) by employing the SWAT (Soil and Water Assessment Tool) model and stochastic methods in different time scales during 1960 to 2017. The contribution of climate changes to hydrological change were quantified by 16 hypothetical scenarios by recombining climatic data. The results show that the annual daily maximum and minimum temperature (Tmax, Tmin) increased while their differences (DTR) decreased. However, there was no significant trend in annual precipitation and hydrological components. The trend of precipitation has a positive impact to the change of all three hydrological components. Although precipitation contributes more to changes in hydrological components, more attention also needs to be given to the change of DTR, which has positive impact of GWF that contrasts with that of BWF and GWS. Seasonal scale studies of these changes suggested that more attention should be paid to the climate change in spring and winter when the hydrological components were more sensitive to climate change. Our results summarized hydrological components variability under the impact of climate change and demonstrated the importance of analyses at different time scales, which was expected to provide a reference for water resources management in other semi-arid river basins. [ABSTRACT FROM AUTHOR]