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Context: In implementing the Murray–Darling Basin Plan, jurisdictions have defined environmental water requirements (EWRs) for sites along Basin rivers. EWRs are the flows (frequency, magnitude, duration, and timing) required to achieve environmental outcomes; they are derived from flow-ecology relationships by using best available scientific knowledge. Aims: To assess EWR achievement across the Murray–Darling Basin over a 43.5-year period (1 July 1979 – 31 December 2022) that included periods of drought as well as widespread flooding. Methods: By using a published EWR assessment tool, we analysed the achievement of EWRs for small fresh, large fresh, bankfull and overbank flows for 23 sites. Key results: At 65% of stream gauge sites assessed, most EWRs evaluated had not been met. We also compared analyses of different time periods, namely, a 43.5-year period, and a 10-year period since the Basin Plan was legislated. This highlighted some improvement in EWR achievement for the small fresh EWR. Conclusions and implications: Despite some improvements, the continued lack of achievement in meeting EWRs is likely to be a major contributing factor to the ongoing poor health of channel, wetland (including Ramsar wetlands) and floodplain ecosystems across most of the rivers of the Murray–Darling Basin. Environmental water requirements (EWRs) are the flows required to keep aquatic ecosystems healthy. We explored whether EWRs had been met across aquatic ecosystems in the Murray–Darling Basin over the past four decades, finding that at 65% of assessed sites they had not been achieved. The most recent decade since Basin Plan legislation has seen some improvement in EWR achievement for small freshes, possibly reflecting active environmental watering. However, across most rivers of the Murray–Darling Basin, poor health of channel, wetland (including Ramsar wetlands) and floodplain ecosystems remain. [ABSTRACT FROM AUTHOR]

Competition between aquatic organisms is heavily influenced by abiotic factors in the environment, specifically flow regime in aquatic systems. Flow regime has been shown to significantly affect the way in which a species uses the environmental resources and alterations in flow can exasperate competitive advantages by congenerics. However, little work has concentrated on the competitive outcome between native and invasive organisms as a function of flow regime. Here, we sought to uncover how competition between two crayfish species (the native virile crayfish [Faxonius virilis] and invasive rusty crayfish [Faxonius rusticus]) was affected by varying flow rates. To do this, we size-matched crayfish and quantified three separate behaviors (food use, shelter use, and fights) of crayfish in four different discharge levels (no discharge—0 cm3/s; low discharge—116 cm3/s; intermediate discharge—345 cm3/s; high discharge—450 cm3/s). We found that the number of foraging bouts was significantly (p < 0.001) influenced by discharge levels for both species, where rusty crayfish foraged more often in no and discharge. The number of times crayfish sheltered also varied between species and was significantly (p < 0.001) altered by discharge level, where rusty crayfish sheltered more often in no discharge and virile crayfish sheltered more in low and intermediate discharge levels. Similarly, the number of fights that crayfish engaged in also significantly (p < 0.001) depended upon species and discharge levels. Rusty crayfish engaged in more agonistic activities in no and high discharge levels while virile crayfish participated most often in low and intermediate discharge levels. [ABSTRACT FROM AUTHOR]

Rivers are the main source of fresh water in mountainous and downstream areas. It is crucial to investigate the possible threats of climate change and understand their impact on river watersheds. In this research, climate change's impact on the mountainous watershed of the Jajrood River, upstream of Latyan Dam in Iran, was assessed by using a multivariate recursive quantile-matching nesting bias correction (MRQNBC) and the soil and water assessment tool (SWAT). Also, this study considered ten global circulation models (GCMs) from the coupled model intercomparison project phase VI (CMIP6). With a higher correlation coefficient, the MIROC6 model was selected among other models. For the future period of 2031–2060, the large-scale outputs of the MIROC6 model, corresponding to the observational data were extracted under four common socioeconomic path scenarios (SSPs 1–2.6, 2–4.5, 3–7.0, 5–8.5). The bias was corrected and downscaled by the MRQNBC method. The downscale outputs were given to the hydrological model to predict future flow. The results show that, in the period 2031–2060, the flow will be increased significantly compared to the base period (2005–2019). This increase can be seen in all scenarios. In general, changes in future flow are caused by an increase in precipitation intensity, as a result of an increase in temperature. The findings indicate that, although the results show an increase in the risk of flooding, considering the combined effects of three components, i.e., increased precipitation concentration, temperature, and reduced precipitation, climate change is intensifying the problem of water scarcity. [ABSTRACT FROM AUTHOR]

This study implemented a coupled SWAT-FEM simulation model to evaluate the impacts of land use land cover and climate change scenarios (LCS) on the water resources of river catchments in Chennai, India. The land use land cover data were obtained by merging the source data from National Remote Sensing Centre (NRSC) and International Water Management Institute (IWMI). Climate change simulations were obtained from four global climate models (GCM), including GFDL Baseline Scenario (1981–2000), GFDL A1B Scenario (2081–2100), CCSM4 Baseline Scenario (1986–2005), and CCSM4 A1B Scenario (2081–2100). The LCS predicted temperature increases of 2.32 °C and 1.74 °C for GFDL and CCSM4, respectively, by the end of the century. The water use predictions suggested increases above 20% in the utilization of water by 2100, inferring the noticeable dynamics of inter-annual as well as inter-month variability in water resources in the river basins of Chennai soon. The study is novel through its implementation of a coupled modeling approach to improve the practicality of the SWAT-FEM model and to deliver useful projections of land and climate change impacts on hydrological responses. The results provide useful insights into how the variability in climate conditions alters the spatiotemporal water responses in catchment scales. [ABSTRACT FROM AUTHOR]

Catchments characteristics, such as geomorphology, geology, soil, land use, and climatic variables, play an important role in total stream flow responses, a critical resource for people and the environment. Most of the previous literatures were applied a conventional statistical regression model to assess the relationship between landscape-climate descriptors, and streamflow and PET. However, a conventional statistical regression model didn't consider dependence of explanatory variables that were collected or extracted across both space and time. This paper investigated the impacts of landscape attributes and climate variables on catchment scale temporal variation of total streamflow and spatio-temporal variation of potential evapotranspiration (PET) in the Mille catchment using multiple linear regression techniques, and the importance of this study was to test spatial autocorrelation in the spatial regression model which is required to properly assess and quantify the relationship between hydrological regime response components and Landscape-climate descriptors in a catchment with topographically complex, and high spatio-temporal climatic variation like in our case study area, the Mille catchment. Statistical regression analysis revealed significant relationships between streamflow and climate variables, especially with rainfall. Mean maximum temperature is the most dominant factor controlling temporal variation of potential evapotranspiration at a monthly scale, whereas NDVI is the most significant factor that controls the spatial variability of PET. The multiple regression model shows that 91.1% of temporal variation in streamflow was accounted for rainfall, whereas, 96.6% and 78.4% of temporal and spatial variation in potential evapotranspiration was accounted for in maximum temperature and NDVI, respectively. Methods also can be applied to catchments with similar landscape attributes and climate variables. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Water Resources Journal / Revue Canadienne des Ressources Hydriques is the property of Taylor & Francis Ltd 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.)

Estimation of dependable flow at different levels is considered one of the important parameters for planning, designing, and managing water-related projects, including hydropower generation, irrigation systems, water use, and river and reservoir sedimentation. For this purpose, the Flow Duration Curve (FDC) is developed by analyzing the available stream flow data at the site when adequate length of observed data are not available. The FDC is a valuable tool for determining the flow patterns of a river and estimating dependable flow. The FDC provides the percentage of time duration during which a stream flow (monthly, seasonal, or annual) is exceeded over a recorded period for a particular river or stream, which can be constructed by adopting the empirical method. By analyzing the FDC, the flow patterns of the Baspa river at the Kuppa barrage were determined, and the dependable flow was estimated. This paper presents a study on the assessment of monthly, seasonal, and annual dependable flow through the FDC by adopting an empirical method for the river Baspa at Kuppa barrage. The study suggests the dependable flow at different percentage levels like 75%, 90%, and 100% obtained from FDCs could be used for planning irrigation, hydropower, and drinking water projects in the study area. [ABSTRACT FROM AUTHOR]

The shrinking of water resources along with the frequent droughts plays an effective role in intensifying the water crisis. Climate change adversely affects the hydrological cycle at the basin level. These are often reflected in the water and food insecurity, frequent hydrologic extremes, frequent drought, flooding, and deteriorating ecosystem health. This study aims to calibrate and validate the stream flows in Awash River basin using a distributed hydrological Water Evaluation And Planning (WEAP) model. Mean monthly Precipitation; temperature and stream flow are used to run the model. The model was calibrated and validated using mean stream flow. The trends of climate over the study basin were also investigated using Mann Kendall trend tests. The results revealed that the value of R² ranged from 0.73 to 0.91 during calibration periods. On the other hand, the value of Nash--Sutcliffe efficiency (NSE) is ranged from 0.65 to 0.83. However, the values of coefficient of determination (R²) during validation periods ranged from 0.54 to 0.91 and the values of Nash--Sutcliffe efficiency (NSE), ranges from 0.50 to 0.84. Thus, The results at two important parts of the main river (upstream and downstream) gauges showed good agreement between the simulated and observed stream flow. The basin receives a significant amount of water during the rainy season (June to September). The mean annual rainfall of the basin ranges from 100 to 1700 mm with great spatiotemporal variation. The annual stream flow of the Awash River basin shows a sharp decreasing trend (Z = -0.120 during the study period. Thus, the findings of this study could provide insights for concerned bodies to implement effective water resources management techniques. The study also proposed that, to ensure the sustainability of water resources, better long-term management policies are required to be implemented in the basin and to meet future downstream water needs. [ABSTRACT FROM AUTHOR]

As air temperature increases, it has been suggested that smaller individual body size may be a general response to climate warming. However, for ectotherms inhabiting cold, highly seasonal environments, warming temperatures may increase the scope for growth and result in larger body size.In a long‐term study of individual brook trout Salvelinus fontinalis and brown trout Salmo trutta inhabiting a small stream network, individual lengths increased over the course of 15 years. As size‐selective gains and losses to the population acted to reduce body sizes and mean body size at first tagging in the autumn (<60 mm) were not observed to change substantially over time, the increase in body size was best explained by higher individual growth rates.For brook trout, increasing water temperatures during the spring (when both trout species accomplish most of their total annual growth) was the primary driver of growth rate for juvenile fish and the environmental factor which best explained increases in individual body size over time.For brown trout, by contrast, reduction in and subsequent elimination of juvenile Atlantic salmon Salmo salar midway through the study period explained most of the increases in juvenile growth and body size.In addition to these major trends, a considerable amount of interannual variation in trout growth and body size was explained by other abiotic (stream flow) and biotic (population density) factors with the direction and magnitude of these effects differing by season, age‐class and species. For example, stream flow was the dominant growth rate driver for adult fish with strong positive effects in the summer and autumn, but flow variation could not explain increases in body size as we observed no trend in flow.Overall, our work supports the general contention that for high‐latitude ectotherms, increasing spring temperatures associated with a warming climate can result in increased growth and individual body size (up to a point), but context‐dependent change in other factors can substantially contribute to both interannual variation and longer‐term effects. [ABSTRACT FROM AUTHOR]

Copyright of Gazi Journal of Engineering Sciences (GJES) / Gazi Mühendislik Bilimleri Dergisi is the property of Gazi Journal of Engineering Sciences 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.)

Copyright of Yellow River is the property of Editorial Board of Yellow River 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.)

The aim of the present study was to detect land cover change for the last three decades and estimate its impact on stream flow dynamics under the current and future scenarios. Landsat satellite imageries were used for land cover classification for selected years (1987, 2002 and 2017). The effect of land cover change on stream flow was evaluated using SWAT model, and its performance was tested. The findings indicated significant land cover changes in the last three decades. Coverage of cultivated land (17%) and bare land (1%) in 1987 increased rapidly to 43 and 17% in 2017. Furthermore, there was 70% agreement between observed and simulated stream flow in both the calibration and validation phases. The stream flow of the watershed was changing significantly in response to land cover dynamics. The evaluation of hydrological response due to land cover change showed a monthly mean stream flow decrease by 12.7 m3/s (−38%) in 1987 and 2017 in dry months. Nevertheless, it showed a monthly mean stream flow increase by 53.06 m3/s (23%) in wet months. Similarly, between the years 2017 and 2047, the stream flow was estimated to increase by 42.84 m3/s (15%) for wet months and a decrease by 13.52 m3/s (−66%) for dry months. Generally, it can be concluded that land cover changes have significant impact on stream flow. Hence, establishing strong land use and water resource policies is an essential means for better evaluation and monitoring of water resource in the study area. [ABSTRACT FROM AUTHOR]

Droughts are one of the multidimensional extreme events that negatively influence agriculture, water availability and food security in the World. The Upper Indus Basin (UIB) is the major river system in the world that contributes 80% of the surface water availability in Pakistan. The objective of the current study is to analyze the spatial patterns of drought severity and magnitude using the standardized precipitation index and streamflow drought index. These drought indices were used to estimate the characteristics and a variation of the droughts annual, pre-monsoon and post-monsoon seasons for the period of 1991–2017. Results revealed that the northeastern side of the Upper Indus Basin was greatly influenced by the droughts as compared to the southwestern side. The duration from 1997 to 1998 was strongly correlated with El Nino and La Nina (ENSO) in a strong way. This type of ENSO indicates the severe drought for 5 years from 1998 to 2002 in the UIB. The episode of the warm water oceans mechanism was also strengthened in 1996, 1997, 1998, 2000, 2001 and 2002 drought years. La Nina effect has been observed in the wet and cold phase during the year of 1999. The study indicated the severe SDI drought in the years of 1991 and 2001. The study also indicated that the streamflow drought index in the post-monsoon season was marked by extreme level drought magnitude at G. Habibullah (2001), Muzaffarabad (2001), Yogo (1993) and Dhok Pathan (1998). The results of the current investigation would help policymakers to introduce new types of drought risk reduction measures for drought preparedness at the regional and the national level in Pakistan. [ABSTRACT FROM AUTHOR]

This study coupled the Soil and Water Assessment Tool (SWAT) with a ground water finite element model (FEM) with the enhancements of multiple interface conversions and management practices. The coupled model, SWAT_FEM was applied to assess the hydrology of the Chennai River basin in India, a coastal zone with significant irrigation. The SWAT_FEM enhanced the predictions of stream flows and ground water levels (R2:0.69,0.81; Nash Sutcliffe Efficiency (NSE):0.64,0.74) compared to the standalone model, SWAT (R2:0.64,0.66; NSE:0.60,0.63) respectively. The coupled model produced an all-inclusive representation of the impacts of management practices on the hydrological processes and generated insights into the spatiotemporal patterns of the surface water and ground water interactions in the study area. The results showed that the interactions of surface water and ground water were significant in the mainstream of Chennai River basin. The seasonal ground water levels obtained with the SWAT_FEM model reinforced the increases in exorbitant ground water abstraction rates (9%-44%) with the introduction of management practices including reservoirs, pond irrigation, and agricultural water use. The results emphasized that if the ground water demand continued to increase, accelerated and unregulated ground water extraction is bound to happen shortly to suffice the water use, which can bring about environmental problems to this basin. Overall, this study demonstrated the applicability of the SWAT_FEM model and its value to the water resources management in irrigated areas with management practices. The developed model can be utilized in water resources assessment tools for effective predictions of ground water contributions in river basins. [ABSTRACT FROM AUTHOR]

Despite the importance of tropical ecosystems for climate regulation, biodiversity, water and nutrient cycles, only a few Critical Zone Observatories (CZOs) are located in the tropics. Among these, most are in humid climates, while very few data exist for semi‐arid and sub‐humid climates, due to the difficulty of estimating hydro‐geochemical balances in catchments with ephemeral streams. We contribute to fill this gap by presenting a meteorological and hydro‐geochemical dataset acquired at the Mule Hole catchment (4.1 km2), a pristine dry deciduous forest located in a biosphere reserve in south India. The dataset consists of time series of variables related to (i) meteorology, including rainfall, air temperature, relative humidity, wind speed and direction, and global radiation, (ii) hydrology, including water level and discharge at the catchment outlet, (iii) hydrogeology, including manual (monthly) and/or automated (from 15 min to hourly) groundwater levels in nine piezometers and (iv) geochemistry, including suspended sediment content in the stream and chemical composition of rainfall (event based), groundwater (monthly sampling) and stream water (storm events, 15 min to hourly frequency with an automatic sampler). The time series extend from 2003 to 2019. Measurement errors are minimized by frequent calibration of sensors and quality checks, both in the field and in the laboratory. Despite these precautions, several data gaps exist, due to occasional access restriction to the site and instrument destruction by wildlife. Results show that large seasonal and interannual variations of climatic conditions were reflected in the large variations of stream flow and groundwater recharge, as well as in water chemical composition. Notably, they reveal a long‐term evolution of groundwater storage, suggesting hydrogeological cycles on a decadal scale. This dataset, alone or in combination with other data, has already allowed to better understand water and element cycling in tropical dry forests, and the role of forest diversity on biogeochemical cycles. As tropical ecosystems are underrepresented by Critical Zone Observatories, we expect this data note to be valuable for the global scientific community. [ABSTRACT FROM AUTHOR]

This paper develops an integrated framework for modeling payment for ecosystem services (PES) mechanisms that deliver multiple environmental services. Specifically, under a community‐led PES, forest conservation is promoted to deliver carbon and stream water benefits. The upstream community is paid for avoided fuelwood harvesting through a United Nations programme on reducing emissions from deforestation and forest degradation (REDD) program, whereas additional income is generated from water sales to the downstream communities. A bio‐economic model derives optimal level of fuelwood harvesting, which in conjunction with the changing species composition of forests, streamflow hydrology and fire risks, impacts on the carbon and water generation potential of the PES project. Results indicate that forest conservation outcomes are better when water and carbon services are combined, however overall cost to the program is lower under a carbon‐based PES. Changing species composition of forests creates tradeoffs between water and carbon benefits. Forest fires further challenge the viability of PES schemes through reducing streamflow and carbon sequestration potential. Recommendations for Resource Managers: Linking two or more environmental services under a single payment for ecosystem services (PES) scheme could improve forest conservation through making it more attractive to the participating communities.PES programs that combine multiple environmental services become economically attractive to participating communities through increasing their incomes. For instance, water and carbon driven services complement each other due to the overlapping benefits from improving forest biomass.However, fire risks can lower the benefits from PES and dissuade community participation.Similarly, the ecological and hydrological dimensions of PES projects that offer carbon and water benefits need to be understood and incorporated within PES framework design to enhance their durability.Conservation of mixed forests is more responsive to water‐based PES payments, in comparison to monoculture oak forests, however, mixed forests are also more vulnerable to degradation in absence of cooking fuel subsidies. [ABSTRACT FROM AUTHOR]

With the development of landscape ecology and hydrology, the research in relationship between landscape pattern changes and hydrological process is pushed into a further level, and also to proposed a higher request to the development of related models. The SWAT-VRR model (Soil and Water Assessment Tool with Vegetation Runoff Regulation) is a distributed hydrological model to better show the effect of land use landscape change on hydrological processes. The Qihe watershed in Danjiangkou reservoir area was selected in a case study, and the applicability of SWAT-VRR was verified firstly, then set up two typical water-soil conservation scenario simulations to analyze the response to landscape pattern changes under SWAT-VRR. The results indicate that, the SWAT-VRR model achieved a notable improvement in monthly and daily hydrological simulation comparing to the SWAT model (Soil and Water Assessment Tool) simulation during 2003 to 2006. Compared with the two land use scenarios, the 300 m forest riparian along the Qihe River can adjust the runoff more effectively than the area greater than 15° is forest, and show a strong stability in water-soil conservation effect during different rainfall. The SWAT-VRR provides a more accurate scientific basis to estimate landscape pattern change on stream flow. [ABSTRACT FROM AUTHOR]

The impact of land use/land cover (LULC) change on the stream flow of the Shaya catchment was assessed by employing the MIKE SHE hydrological model. The digital elevation model, soil, LULC, climate, and stream flow data were used as model inputs. The LULC was analyzed from different years of satellite imageries using ERDAS IMAGINE software package and its accuracy was verified following the standard procedures. Trend and shift detection analysis were also conducted to study the effect of rainfall on stream flow using the Mann–Kendall (MK) and Pettit tests, respectively. The result showed that there is a significant expansion of settlement and agricultural area, while there was a decrease of bare land, forest, and bush land in the catchment. In contrary, rangeland was increased from the year 1987 to 2000 and then decreased from 2000 to 2015. The performance of the MIKE SHE hydrological model was very good both during model calibration and validation periods. It has been observed that rainfall did not show any significant trends and shifts, but the stream flow was increased significantly in the two decades. In this study, the effects of LULC change on the stream flow in the study area have been distinguished: the mean monthly stream flow was increased during the wet season, while it was decreased during the dry season. Therefore, we recommend concerned bodies to monitor and take appropriate control of the LULC changes, especially settlement and deforestation, before it makes acute problems of the hydrologic imbalance in the catchment. [ABSTRACT FROM AUTHOR]

The southern Rocky Mountains serve as the headwaters of the West, providing water to agriculture, industry, recreation, and millions of people in 17 western states. Eighty percent of the water draining land managed by the United States Department of Agriculture Forest Service (Forest Service) is from snowmelt. The demand for this water continues to grow with increasing population throughout the arid West. The Forest Service is obliged to manage these watersheds for a diverse set of interests including extraction of forest products and other natural resources, providing recreational opportunities, and delivering fresh water. The Forest Service is simultaneously required to sustain the ecological condition of the managed lands for future generations. Satisfying these demands requires quantitative approaches to balance the ecological impacts against the benefits of water development. In this study, we (1) measured riparian vegetation at nine sites in the Medicine Bow‐Routt National Forests, (2) identified twelve trait‐based riparian vegetation‐flow response guilds (functionally similar groups of plants), (3) constructed reach‐scale hydraulic models for each site, (4) classified sites by hydro‐geomorphic characteristics, and (5) modeled observed guild distributions as a function of duration of stream inundation and site characteristics. To illustrate the application of these models in quantifying ecological impacts of water development and management decisions, flow scenarios were developed to simulate the effects of upstream diversions and reservoirs. Guild distribution models were then used to forecast alterations to vegetation patterns under the flow simulations. Even in these relatively moist montane riparian areas, stream inundation duration explained much of the variability in guild distributions. Controlling for groundwater contributions to the moisture regime improved the predictive ability of the models. Plot‐level guild diversity was found to be most correlated to the maximum height of species in the guild, shade tolerance, and seed mass. Plots were identified with relatively low species diversity and high guild diversity, suggesting niche partitioning and a target guild composition for restoring resilient riparian vegetation assemblages. We demonstrate the transferability of guild models across rivers to assist in the decision‐making process for evaluating water development and forecasting riparian vegetation response. [ABSTRACT FROM AUTHOR]

Freshwater organisms are threatened by changes in stream flow and water temperature regimes due to global climate change and anthropogenic activities. Threats include the disappearance of narrow‐tolerance species and loss of favorable thermal conditions for cold‐adapted organisms. Mayflies are an abundant and diverse indicator of river health that performs important functional roles. The relative importance of key hydro‐environmental factors such as water temperature and flow volumes in structuring these communities has rarely been explored in the tropical regions of Africa. Here, we investigate the response of mayfly species diversity to these factors in the Luvuvhu catchment, a strategic water source area in the arid northeastern region of South Africa. Mayfly larvae were sampled monthly in stones‐in‐current biotopes across 23 sites over a one‐year period. The relationship between these environmental drivers and mayfly diversity was modeled using linear mixed effects models (LMMs) and a model‐based multivariate approach. Threshold Indicator Taxa Analysis (TITAN) was used to model the response of mayfly species to important gradients and identify thresholds of change. Site‐specific characteristic were the most important predictor of mayfly diversity, and there was considerable variation over time, with mayfly diversity peaking during winter. Along this, gradient temperature was the best predictor of assemblage structure, with five out of six reliable indicator species being cold‐adapted, and a community threshold response at 19°C. Results support laboratory‐based thresholds of temperature for mayfly species survival and development, extending empirical evidence to include field‐based observations. Increased global (climate change) and local (riparian vegetation removal, impoundments) changes are predicted to have negative impacts on mayfly diversity and ultimately on ecosystem function. [ABSTRACT FROM AUTHOR]

Context: Landscape composition and configuration determine the generation and exchange of water flows among different landscape patches and may affect catchment hydrological flows and variations. However, the poor understanding on the effects of landscape patterns on hydrological processes limits the implementation of landscape planning and management practices for regulating catchment water resources at the practical level. Objectives: The aims are to determine the relationship between the landscape pattern and hydrological flows and variations, and to compare the contributions of landscape composition and configuration to the hydrological flows and variations. Methods: Landscape patterns were quantified and hydrological flows and variations were observed in a Chinese subtropical catchment with ten sub-catchments during 2011–2017. The relationship among landscape composition, configuration, and hydrological flows and variations was analysed by Pearson correlation, and their relative contributions were determined by the variance partitioning analysis. Results: Landscape composition and configuration were significantly correlated with catchment stream, direct, and base flows and variations, of which high fragmentation degree increased stream and base flows, great shape complexity aggravated the volatility of stream flow, high patch aggregation adversely impacted stream, direct, and base flows, and high patch evenness and lower richness increased stream and base flows. Landscape composition and configuration indices could be employed to effectively predict hydrological flows and variations. Conclusions: Landscape configuration had greater contribution than landscape composition to subtropical catchment hydrological flows and variations, and optimizing landscape configuration could improve our regulatory capacity and ability of catchment water resources management and utilization in the subtropical catchments at the practical level. [ABSTRACT FROM AUTHOR]

The Rocky Mountain Biological Laboratory (RMBL; Colorado, USA) is the site for many research projects spanning decades, taxa, and research fields from ecology to evolutionary biology to hydrology and beyond. Climate is the focus of much of this work and provides important context for the rest. There are five major sources of data on climate in the RMBL vicinity, each with unique variables, formats, and temporal coverage. These data sources include (1) RMBL resident billy barr, (2) the National Oceanic and Atmospheric Administration (NOAA), (3) the United States Geological Survey (USGS), (4) the United States Department of Agriculture (USDA), and (5) Oregon State University's PRISM Climate Group. Both the NOAA and the USGS have automated meteorological stations in Crested Butte, CO, ~10 km from the RMBL, while the USDA has an automated meteorological station on Snodgrass Mountain, ~2.5 km from the RMBL. Each of these data sets has unique spatial and temporal coverage and formats. Despite the wealth of work on climate‐related questions using data from the RMBL, previous researchers have each had to access and format their own climate records, make decisions about handling missing data, and recreate data summaries. Here we provide a single curated climate data set of daily observations covering the years 1975–2022 that blends information from all five sources and includes annotated scripts documenting decisions for handling data. These synthesized climate data will facilitate future research, reduce duplication of effort, and increase our ability to compare results across studies. The data set includes information on precipitation (water and snow), snowmelt date, temperature, wind speed, soil moisture and temperature, and stream flows, all publicly available from a combination of sources. In addition to the formatted raw data, we provide several new variables that are commonly used in ecological analyses, including growing degree days, growing season length, a cold severity index, hard frost days, an index of El Niño‐Southern Oscillation, and aridity (standardized precipitation evapotranspiration index). These new variables are calculated from the daily weather records. As appropriate, data are also presented as minima, maxima, means, residuals, and cumulative measures for various time scales including days, months, seasons, and years. The RMBL is a global research hub. Scientists on site at the RMBL come from many countries and produce about 50 peer‐reviewed publications each year. Researchers from around the world also routinely use data from the RMBL for synthetic work, and educators around the United States use data from the RMBL for teaching modules. This curated and combined data set will be useful to a wide audience. Along with the synthesized combined data set we include the raw data and the R code for cleaning the raw data and creating the monthly and yearly data sets, which facilitate adding additional years or data using the same standardized protocols. No copyright or proprietary restrictions are associated with using this data set; please cite this data paper when the data are used in publications or scientific events. [ABSTRACT FROM AUTHOR]

Urban streams provide important ecosystem services to cities' population, from the maintenance of urban biodiversity, temperature, humidity and air quality to improving aesthetics and provision of natural areas for recreation. However, these streams are under multiple-stressors, including artificialization of the channel and flow, poor water quality and cut of riparian vegetation which puts in risk their ecological integrity and consequently their services. In this study, we aimed to understand variations in macroinvertebrate communities and in biological condition as a response to flow and water quality, by following a Mediterranean urban stream over 8 months (December–July). With a monthly periodicity, we sampled invertebrate communities and characterized in situ water physicochemical parameters. The urban stream studied showed a high variation of environmental factors over time. Invertebrate communities were generally poor, with some Ephemeroptera (Baetis sp.) but was dominated by Chironomidae and Oligochaeta that changed over time alongside with environmental conditions. Biological quality based on the Portuguese Invertebrates Index (IPtIS) varied between poor and bad. Multivariate community patterns (at genus level) showed variations in communities over time, as well as in their biological trait patterns (invertebrates' maximal size, reproduction mode, resistance form, feeding habits and locomotion mode). Periods displaying worse biological quality, less diverse communities and lower functional richness corresponded to peaks of discharge, higher conductivity and hardness while the best quality communities were found under lower nitrate concentrations. Our study points out that the detection of impacts or recovery in urban streams through invertebrate communities might require at least the use of genus level as family level does not detect smoother changes. Communities reflect the complex interplay of environmental variables affecting structural and functional natural patterns and ultimately the biological condition of this urban stream. Rehabilitation measures should carefully consider this complex interplay of variables to enhance quality and ecosystem services. [ABSTRACT FROM AUTHOR]

In the majority of small urban catchments, there is a problem with obtaining precipitation data necessary for hydrological applications and analyses in the scope of assessing flood risk. One of the means of measuring rainfall depth is to make use of weather radar technology, which provides information on the spatial and temporal distribution of rainfall in a catchment. In the work, the dependency between radar reflectivity (Z) and rainfall rate (R) was determined on the basis of a few events measured at two precipitation stations located in the Służewiecki Stream catchment in Warsaw, Poland. Making use of the Z-R relationship as well as values of radar reflectivity, the amount of rainfall for the analysed event was calculated and compared with the amounts of rainfall measured using rain gauges. Relatively good compatibility between the rainfall totals was obtained for the majority of events. Rainfall depths obtained for two selected events on the basis of data from the weather radar were applied to simulate flows in the analysed catchment using the SWMM (Storm Water Management Model) hydrodynamic model. Values of the relative error calculated on the basis of measured flows and flows calculated in reaction to rainfalls estimated using the Z-R relationship were, in the majority of cases, lower than 25%. Simulations carried out on the SWMM model for a few rainfall scenarios in response to rainfall depth measured at precipitation stations and estimated on the basis of radar data revealed the possibility of the occurrence of flooding in the catchment as a result of the overflow of rainfall collectors. [ABSTRACT FROM AUTHOR]

Trend, detection, and attribution analyses were performed using naturalized streamflow observations and routed land surface model runoff for 10 subbasins in the Columbia River Basin during water years 1951–2008. The Energy Exascale Earth System land‐surface model (ELM) version 1.0 and the Routing Application for Parallel computatIon of Discharge (RAPID) routing model were used to conduct semi‐factorial simulations driven by multiple sets of bias‐corrected forcing data sets. Four main potential drivers, including climate change (CLMT), CO2 concentration (CO2), nitrogen deposition (NDEP), and land use and land cover change (LULCC), were analyzed during the assessment. All subbasins showed significant (α = 0.10) declines in the observed amount of annual total streamflow, except for the Middle and Upper Snake and Upper Columbia Subbasins. These declines were led by significant decreases in June–October streamflow, which also directly led to significant decreases in peak and summer streamflow. Except for the Snake River Subbasins, LULCC had the same pattern of declines in monthly streamflow, but the period was shifted to May–September. NDEP also had significant trends in June–October; however, rather than decreases, the trends showed significant increases in streamflow. While there were significant trends in CO2, NDEP, and LULCC, their signals of change were weak in comparison to the signal in CLMT and the natural internal variability found in streamflow. Overall, the detection and attribution analysis showed that the historical changes found in annual total, center of timing of, and summer mean streamflow could be attributed to changing climate and variability. Key Points: Latest NRNI data, ELM simulations, and river routing model were employed to study the long‐term hydrologic changes in CRBSignificant declines in the CRB June–October streamflow led to an earlier center of timing and significant decreases in annual total, summer mean, and peak streamflowThe changes in annual total, summer mean, and center of timing of streamflow were mainly attributed to changing climate and variability [ABSTRACT FROM AUTHOR]

Due to rapid growth of Nakhon Ratchasima province. Land use and Land cover change (LULC) change takes place in surrounding end point of Motorway of Nakhon Ratchasima municipality and its vicinity, various types of environmental impacts occur in the area. Main objectives of the study are to assess built-up growth rate and mapping from transition matrix of satellite image during 2013-2016. Results of the built-up growth prediction of land cover in 2021 using CA-Markov showed that Motorway road was the strongest predictor variable and the most vulnerable land use lost was miscellaneous. Urban and built-up areas had continuously increased while agricultural and forest had continuously decreased. Urban growth pattern was linear strip development but its pattern was changed to be a scattered development. The simulated area results in a shorter flow of water in stream order 1 to 2. The direction of the flow of water away from the main river (Lamtaklong). However, the forecast of urban growth pattern remains problematic because the model performed with a relatively moderate predictive ability (60%) at a spatial unit of 1 km. x 1 km. This application of the CA-Markov model demonstrated an ability to address a range of local planning issue, but spatial accuracy and variable selection were among the factors that must be further considered for practical application. [ABSTRACT FROM AUTHOR]

Drought is a natural event that can have significant impact on the economy. Pakistan is a semi-arid country where hydrological drought generally causes adverse impacts on agricultural production and hydropower generation. In this research, the characteristics of hydrological droughts in Indus River basin using stream flow data of major rivers of Pakistan were investigated. Stream flow drought indices (SDI) were used to determine the severity of droughts for the Indus, Jhelum, Chenab and Kabul River at Tarbela, Mangla, Marala and Warsak hydrological stations for the period 1962-2011. A drought spell starting from 1999 and ending in 2002 was observed for all stations and is considered to be the worst drought in the history of Pakistan. Analysis of historical streamflow data indicated an increased occurrence of droughts in the last 12 years, which may be attributed to climate change. Extreme drought events were observed at Tarbela during October-September and at Mangla during October-June with SDI value of -2.36 and -2.74, respectively. Moderate to severe wet conditions were also detected in the analysis period. Several strategies for the mitigation of adverse impacts of droughts in the study region are recommended. [ABSTRACT FROM AUTHOR]

Drought is a natural event that can have significant impact on the economy. Pakistan is a semiarid country where hydrological drought generally causes adverse impacts on agricultural production and hydropower generation. In this research, the characteristics of hydrological droughts in Indus River basin using stream flow data of major rivers of Pakistan were investigated. Stream flow drought indices (SDI) were used to determine the severity of droughts for the Indus, Jhelum, Chenab and Kabul River at Tarbela, Mangla, Marala and Warsak hydrological stations for the period 1962-2011. A drought spell starting from 1999 and ending in 2002 was observed for all stations and is considered to be the worst drought in the history of Pakistan. Analysis of historical streamflow data indicated an increased occurrence of droughts in the last 12 years, which may be attributed to climate change. Extreme drought events were observed at Tarbela during October-September and at Mangla during October-June with SDI value of -2.36 and -2.74, respectively. Moderate to severe wet conditions were also detected in the analysis period. Several strategies for the mitigation of adverse impacts of droughts in the study region are recommended. [ABSTRACT FROM AUTHOR]

Watershed-scale water quality models are often used for interpreting changes in complex environmental systems. Precipitation is a primary control affecting the output of watershed-scale water quality model, and higher resolution of precipitation data is highly desirable. The objective of this study was to investigate whether the radar rainfall estimates can improve the accuracy of stream flow, TSS load, and TP load simulations with the soil and water assessment tool for high- and low-flow conditions. Yeongsan River watershed (YRW) was selected for this study. This watershed, located south-west of Korean Peninsula, has an area of about 2,938 km², and is divided into 25 sub-watersheds. The simulations were conducted under different rainfall datasets: (1) rainfall observations from nine ground rain gauges (GR), (2) 25 corrected radar rainfall estimates (RR), and (3) a combination of nine ground rain gauges and 16 corrected radar rainfall estimates that represent the 16 ungauged sub-watersheds in YRW (GARR). Simulation results under different the rainfall datasets were compared using the Nash–Sutcliffe efficiency coefficient and percentage bias. The prediction of both high and low stream flows using GARR was better than using GR and RR data. The model performance for predicting TSS load was significantly better under GARR data than under GR and RR data. In case of TP, the model performances using RR and GARR data were significantly better than that using GR data. Overall, combining gauge rainfall and corrected radar rainfall led to an improvement in the prediction accuracy for the watershed-scale water quality model. [ABSTRACT FROM AUTHOR]

Resolution of data is a sensitive issue in hydrological modeling. The sensitivity of stream flow simulated with the Soil and Water Assessment Tool (SWAT) model to Digital Elevation Model (DEM) resolution has been partially understood. However, few studies on the effect of the influence of DEM with resolution over 20 m on daily runoff modeling. The objective of this study was to enhance understanding the impact of DEM (from 8 m to 900 m) within the SWAT model to simulate runoff on annual, monthly and daily scale. The Qihe river, one of the headwaters of Danjiangkou reservoir, was selected as the study area. The key findings were as follows: (1) As DEM resolution becomes coarser, the extracted land form tends to be flat, and the total area of watershed, maximum elevation, and maximum slope generally show a decreasing trend, while the minimum elevation and minimum slope show an increasing trend. (2) The DEM resolution directly affect the water generation and concentration, the increase of DEM mesh size would result in homogenization of simulated stream flow and flood peak attenuation. (3) When DEM resolution is higher than 30 m, the simulated annual and monthly runoff remain unchanged, but the simulated daily runoff will be different very much. The higher the resolution is, the better the simulation results will be, especially for the simulation of flood peak. Therefore, a DEM with higher resolution can describe the runoff process more precisely. [ABSTRACT FROM AUTHOR]

This study was carried out to assess the reliability of Thomas-Fiering's method of stream flow prediction. The 19 years gauged data of 1955-1973 was extended to 2016 using the model. Model calibration was done by multiple linear regressions of the gauged and synthetic data of 1956-1973. The linear equations developed for January to December were used for adjustment of the three sets of stream flow data generated for 1974-2016. The reliability assessment was done based on the extent to which the unbiased statistics (mean, standard deviation and correlation coefficients) of the 1955-1973 stream flow data were preserved in the synthetic stream flow for 1955-2016. The comparison was done using linear regression and One-Way ANOVA (95% Confidence level) to check for the reliability of the generated data. The coefficients of determination, P-values, F-values and critical F-values were used to estimate the reliability index. Synthetic data was found to be 95.9% reliable. [ABSTRACT FROM AUTHOR]

This study applied a time series evapotranspiration (ET) data derived from the remote sensing to evaluate Soil and Water Assessment Tool (SWAT) model calibration, which is a unique method. The SWAT hydrologic model utilized monthly stream flow data from two US Geological Survey (USGS) stations within the Big Sunflower River Watershed (BSRW) in Northwestern, Mississippi. Surface energy balance algorithm for land (SEBAL), which utilized MODerate Resolution Imaging Spectro-radiometer (MODIS) to generate monthly ET time series data images were evaluated with the SWAT model. The SWAT hydrological model was calibrated and validated using monthly stream flow data with the default, flow only, ET only, and flow-ET modeling scenarios. The flow only and ET only modeling scenarios showed equally good model performances with the coefficient of determination (R) and Nash Sutcliffe Efficiency (NSE) from 0.71 to 0.86 followed by flow-ET only scenario with the R and NSE from 0.66 to 0.83, and default scenario with R and NSE from 0.39 to 0.78 during model calibration and validation at Merigold and Sunflower gage stations within the watershed. The SWAT model over-predicted ET when compared with the Modis-based ET. The ET-based ET had the closest ET prediction (~8% over-prediction) as followed by flow-ET-based ET (~16%), default-based ET (~27%) and flow-based ET (~47%). The ET-based modeling scenario demonstrated consistently good model performance on streamflow and ET simulation in this study. The results of this study demonstrated use of Modis-based remote sensing data to evaluate the SWAT model streamflow and ET calibration and validation, which can be applied in watersheds with the lack of meteorological data. [ABSTRACT FROM AUTHOR]

In this paper, an advanced stream flow forecasting model is developed by applying data-preprocessing techniques on adaptive neuro-fuzzy inference system (ANFIS). Wavelet multi-resolution analysis is coupled with an ANFIS model to develop a hybrid wavelet neuro-fuzzy (WNF) model. Different models with different input selection and structures are developed for daily, weekly and monthly stream flow forecasting in Railway Parade station on Ellen Brook River, Western Australia. The stream flow time series is decomposed into multi-frequency time series by discrete wavelet transform using the Haar, Coiflet and Daubechies mother wavelets. The wavelet coefficients are then imposed as input data to the neuro-fuzzy model. Models are developed based on Takagi- Sugeno-Kang fuzzy inference system with the grid partitioning approach for initializing the fuzzy rule-based structure. Mean-square error and Nash-Sutcliffe coefficient are chosen as the performance criteria. The results of the application show that the right selection of the inputs with high autocorrelation function improves the accuracy of forecasting. Comparing the performance of the hybrid WNF models with those of the original ANFIS models indicates that the hybrid WNF models produce significantly better results especially in longer-term forecasting. [ABSTRACT FROM AUTHOR]

Accurate stream flow (SF) prediction is considered among the basic requirements in dealing with several problems associated with the planning, designing and management of water resources and river systems. Multi-layer perceptron network (MLP), was employed to develop artificial intelligence-based models to predict the hourly SF in downstream areas from upstream water level and rainfall records in the Selangor River basin which is a paradigm of humid tropical rivers. Hourly SF, rainfall and water level records of a one-year period (2011) were applied to train and test the MLP-based models which comprise six different combinations of input variables. The developed models’ performance was evaluated via the training, testing data set and overall data. The results of the performance evaluation criteria, i.e. correlation co-efficient (R) and mean absolute error (MAE) indicates that high prediction accuracy was attained. The best fit MLP model is M6-MLP with the highest R and lowest MAE. The R between the observed and predicted hourly SF by the M6-MLP model is 0.898 and 0.904, while the MAE is 10.922 and 10.83 for the training and testing data sets, respectively. The results demonstrate that the MLP technique is successfully applied with high accuracy for hourly SF prediction. [ABSTRACT FROM AUTHOR]

Comparisons of community-level functional traits across environmental gradients have potential for identifying links among plant characteristics, adaptations to stress and disturbance, and community assembly. We investigated community-level variation in specific leaf area (SLA), plant mature height, seed mass, stem specific gravity (SSG), relative cover of C4 species, and total plant cover over hydrologic zones and gradients in years 2013 and 2014 in the riparian plant community along the Colorado River in the Grand Canyon. Vegetation cover was lowest in the frequently inundated active channel zone, indicating constraints on plant establishment and production by flood disturbance and anaerobic stress. Changes in trait values over hydrologic zones and inundation gradients indicate that frequently inundated plots exhibit a community-level ruderal strategy with adaptation to submergence (high SLA and low SSG, height, seed mass, C4 relative cover), whereas less frequently inundated plots exhibit adaptation to drought and infrequent flood disturbance (low SLA and high SSG, height, seed mass, C4 relative cover). Variation in traits not associated with inundation suggests niche differentiation and multiple modes of community assembly. The results enhance understanding of future responses of riparian communities of the Grand Canyon to anticipated drying and changes in hydrologic regime. [ABSTRACT FROM AUTHOR]

Assessing the effectiveness of conservation practices under changed climatic conditions has proven to be invaluable in selecting the adaptation practices. Conservationists are concerned that past effective practices may no longer be effective in the future climate change. This research is aimed at assessing the effectiveness of soil and water conservation practices under future climate change, with respect to sediment yield leaving a watershed. For this purpose, the Soil and Water Assessment Tool, SWAT, was applied to simulate various climate change scenarios with three soil and water conservation practices to assess possible changes in stream flow, and sediment yield of the Gorganroud watershed in the northern part of Iran. Study results demonstrated that the impact of climate change in the increase of watershed sediment yield is more than the stream flow and varies from 35.9 to 47.7% for the period 2040-2069. Implementing conservation practices under climate change can reduce the sediment yield of watershed up to 7.2% and for the sub-basin scale up to 46.4%. Range management practices were found to be the most effective practice in the decrease of sediment at the sub-basin scale and porous gully plugs and terrace construction, the most effective at the watershed scale. The results indicate that soil and water conservation practices will be more effective at reducing sediment yields under anticipated future climates. Though, implementation of each conservation practice solely was not sufficient to compensate for climate change-driven increases in sediment yield. This study provides valuable information for watershed managers and decision makers regarding selection of soil and water conservation practices for adaptation to climate change. [ABSTRACT FROM AUTHOR]

Hydroclimatology is an expansive discipline largely concerned with understanding the workings of the hydrological cycle in a climate context. Acknowledging this, and given the burgeoning interest in the relation between climate and water in the context of working towards an improved understanding of the impacts of climatic variability on water resources, this progress report turns its attention to the connection between large-scale modes of climatic variability and hydrological variability in streams, lakes and groundwater. A survey of the recent literature finds that a plethora of teleconnection indices have been employed in the analysis of hydrological variability. Indices representing modes of climatic variability such as El Niño Southern Oscillation, the North Atlantic Oscillation, the Pacific North America pattern, the Pacific Decadal Oscillation and Atlantic Meridional Oscillation dominate the literature on climatic and hydrological variability. While examples of discernible signals of modes of climatic variability in stream flow and lake and groundwater level time series abound, the associations between periodic to quasi-period oscillations in atmospheric/ocean circulation patterns and variability within the terrestrial branch of the hydrological are far from simple, being both monotonic (linear and non-linear) and non-monotonic and also conditional on period of analysis, season and geographic region. While there has been considerable progress over the last five years in revealing the climate mechanisms that underlie the links between climatic and hydrological variability, a bothering feature of the literature is how climatic and hydrological variability is often viewed through a purely statistical lens with little attention given to diagnosing the relationship in terms of atmosphere and ocean physics and dynamics. Consequently, significant progress remains to be made in obtaining a satisfactory hydroclimatological understanding of stream flow, lake and groundwater variability, especially if hydroclimatological knowledge is to be fully integrated into water resource management and planning. [ABSTRACT FROM AUTHOR]

Changes in the stream flow of the Samin catchment (277.9 km²) in Java, Indonesia, have been attributed to land use change and climate change. Hydroclimatic data covering the period 1990-2013 and land use data acquired from Landsat satellite imageries for the years 1994 and 2013 were analysed. A quantitative measure is developed to attribute stream flow changes to land use and climate changes based on the changes in the proportion of excess water relative to changes in the proportion of excess energy. The results show that 72% of the increase in stream flow might be attributed to land use change. The results are validated by a land use change analysis and two statistical trend analyses namely the Mann-Kendall trend analysis and Sen's slope estimator for mean annual discharge, rainfall and potential evapotranspiration. The results of the statistical trend analysis are in the same direction as the results of the attribution analysis, where climate change was relatively minor compared to significant land uses change due to deforestation during the period 1994-2013. We conclude that changes in stream flow can be mainly attributed to land use change rather than climate change for the study catchment. [ABSTRACT FROM AUTHOR]

This paper re-examines the problem of the flow of a fluid of finite depth over two Gaussian-shaped obstructions on the stream bed. A weakly nonlinear analysis in the form of the Korteweg–de Vries equation is used to compare with the results of the fully nonlinear problem. The main focus is to find waveless subcritical solutions, and contours showing the obstruction height and separation values that result in waveless solutions are found for different Froude numbers and different obstruction widths. [ABSTRACT FROM PUBLISHER]

Runoff connectivity depends on topography, rainfall, man-made elements (terraces, trails, roads and drainage systems) and vegetation. In this study, we quantified the effects of 70 years of human activities on runoff connectivity in the mountainous Araguás afforested sub-catchment (17·2 ha; Central Spanish Pyrenees). The IC index of hydrological connectivity was chosen to perform this metric over six land use scenarios at high spatial resolution (1 × 1 m of cell size). The current scenario (year 2012) was simulated with three flow accumulation algorithms (MD, MD8 and D8). MD8 was linked with the most frequent hydrological response of the sub-catchment (rainfall intensity and stream flow during 7 years) and generated the most representative pattern of connectivity, especially in the linear landscape elements (LLE). This algorithm was chosen to simulate five past scenarios (1945, 1956, 1973, 1980 and 2006). In all scenarios, the highest connectivity appeared related to trails and roads, as well as to streams and gullies, whereas the lowest appeared related to stonewalls in 1945 and 1956 to hillslopes in 1973, and the following afforestation. Changes in connectivity mainly depended on the changes in the vegetation factor and in a minor way in the total length, spatial location and type of LLE. Afforestation promoted lower and more stable connectivity at both local and catchment scales. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The goal of this research was to determine the changes in streamflow, dissolved inorganic nitrogen ( DIN) leaching and export to the Gulf of Mexico associated with a range of large-scale dedicated perennial cellulosic bioenergy production scenarios within in the Mississippi-Atchafalaya River Basin ( MARB). To achieve this goal, we used Agro- IBIS, a vegetation model capable of simulating the biogeochemistry of row crops, miscanthus and switchgrass, coupled with THMB, a hydrology model capable of simulating streamflow and DIN export. Simulations were conducted at varying fertilizer application rates (0-200 kg N ha−1) and fractional replacement (5-25%) of current row crops with miscanthus or switchgrass across the MARB. The analysis also includes two scenarios where miscanthus and switchgrass ( MRX and MRS, respectively) each replace the ca. 40% of maize production currently devoted to ethanol. Across the scenarios, there were minor reductions in runoff and streamflow throughout the MARB, with the largest differences (ca. 6%) occurring for miscanthus at the highest fractional replacement scenarios in drier portions of the region. However, differences in total MARB discharge at the basin outlet were less than 1.5% even in the MRX scenario. Reductions in DIN export were much larger on a percentage basis than reductions in runoff, with the highest replacement scenarios decreasing long-term mean DIN export by ca. 15% and 20% for switchgrass and miscanthus, respectively. Fertilization scenarios show that significant reductions in DIN leaching are possible even with application rates of 100 and 150 kg N ha−1 for switchgrass and miscanthus, respectively. These results indicate that, given targeted management strategies, there is potential for miscanthus and switchgrass to provide key ecosystem services by reducing the export of DIN, while avoiding hydrologic impacts of reduced streamflow. [ABSTRACT FROM AUTHOR]

Salmonids have been introduced globally, and native and invasive salmonids co-exist in many regions. However, their responses to seasonal weather variation and global climate change are poorly known., The aim of this study was to compare effects of inter-annual variation in seasonal weather patterns on native brook trout (BKT) ( Salvelinus fontinalis) versus invasive rainbow trout (RBT) ( Oncorhynchus mykiss) abundance using summer electrofishing data (May through September) spanning 28 years in the Great Smoky Mountains National Park, U.S.A. ( c. 200 stream sites per species). In particular, we tested if different spawning timing between BKT (autumn) and RBT (late winter) would result in heterogeneous population responses to high seasonal precipitation, which would negatively affect early life stages with impaired swimming ability., As predicted, young-of-the-year (YOY) abundance of autumn-spawning BKT was most strongly impacted by total precipitation between February and March, and RBT YOY abundance was most strongly impacted by peak precipitation between April and May. Despite the presence of these different key seasonal drivers, inter-annual variation in YOY density of these two species was positively correlated because precipitation in April and May also impacted the abundance of BKT YOY., Adult abundance was less responsive to weather variation than YOY abundance, and was most strongly correlated with YOY abundance in the previous year, indicating the importance of flow-driven population control influences on early life stages affecting population sizes into subsequent years. Adult BKT densities were not affected by any weather covariate, whereas adult RBT densities were correlated with four weather covariates in competing models. As a result, there was no correlation in the inter-annual variation in adult density in these two species., The differing responses of BKT and RBT to long-term seasonal weather patterns suggest that they will likely respond differently to global climate change. In particular, winter precipitation will likely be the key environmental driver of differences in their population responses. [ABSTRACT FROM AUTHOR]

This study assesses variability, trends, and teleconnections of stream flow with large-scale climate signals (global sea surface temperatures (SSTs)) for the Omo-Ghibe River Basin of Ethiopia. Fourteen hydrological indices of variability and extremes were defined from daily stream flow data series and analyzed for two common periods, which are 1972-2006 for 5 stations and 1982-2006 for 15 stations. The Mann-Kendall's test was used to detect trends at 0.05 significance level, and simple correlation analysis was applied to evaluate associations between the selected stream flow indices and SSTs. We found weak and mixed (upward and downward) trend signals for annual and wet ( Kiremt) season flows. Indices generated for high-flow (flood) magnitudes showed the same weak trend signals. However, trend tests for flood frequencies and low-flow magnitudes showed little evidences of increasing change. It was also found that El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) are the major anomalies affecting stream flow variability in the Omo-Ghibe Basin. The strongest associations are observed between ENSO/Niño3.4 and the stream flow in August and September, mean Kiremt flow (July-September), and flood frequency (peak over threshold on average three peaks per year (POT3_Fre)). The findings of this study provide a general overview on the long-term stream flow variability and predictability of stream flows for the Omo-Ghibe River Basin. [ABSTRACT FROM AUTHOR]

Given Jordan's limited water resources and the doubling of its population over the last two decades, the gap between water demand and supply has been constantly increasing. Climate change is anticipated to worsen this situation by jeopardizing existing water resources. In the present study, SWAT was used to assess the impacts of climate change on water resources in the northern regions of Jordan. Global climate models (GCM) were used to assess the future impacts of climate change on water resources in the study area. The analyses of three different GCM-generated datasets indicate that stream flow rates are expected to decrease by up to 22 % by the year 2080. This decrease will be particularly severe in the months of maximum peak flow (February and March), perhaps reaching as much as 35-40 %. A minor increase in stream flow rates is expected to occur in some months. Based on these results, impacts of climate change are projected to raise water deficits in Jordan. Therefore, it is crucial to review Jordan's 2008-2022 National Water Strategy. [ABSTRACT FROM AUTHOR]

In the context of changing climate, this study assessed the effects of global warming on water resources in Tanzania for the mid- 21st century. Climate projections from six global circulation models under the most extreme emission scenario (RCP 8.5) were used as inputs to the soil and water assessment tool (SWAT) to examine the effects. The results were analyzed both at spatial (country-level, watershed-level, and subbasin-level) and temporal (annual and seasonal) scales concerning potential and actual evapotranspiration, surface runoff, water yield, and soil moisture. At the country level, the results showed a 0.8-27.4% increase in annual precipitation, which led to a general increase in evapotranspiration (-2.2-7.3%), surface runoff (12.6-94.1%), water yield (7.5-73.4%), and soil moisture (2.9-20.7%). Watershed-level analysis showed 2.4-31.5%, -2.6-6.8%, 18.4-159.7%, and 3.2-22.8% changes in average precipitation, evapotranspiration, surface runoff, and soil moisture, respectively. While no distinct spatial trend was identified for evapotranspiration and surface runoff, soil moisture was projected to increase in the majority of the areas during both the wet and dry seasons. Probability analysis at the subbasin level showed that less than 15% of the area, during the wet season, experienced decline in precipitation, soil moisture, potential and actual evapotranspiration, surface runoff and water yield, while less than 86% of the country experienced decline during the dry season. Overall, the climate change was found to create a more favorable condition for agricultural production during the wet season by increasing the supply of water, but in the dry season, less favorable conditions were projected. [ABSTRACT FROM AUTHOR]

The Poyang Lake Basin has been suffering from severe water problems such as floods and droughts. This has led to great adverse impacts on local ecosystems and water resource utilization. It is therefore important to understand stream flow changes and their driving factors. In this paper, the dynamics of stream flow and precipitation in the Poyang Lake Basin between 1961 and 2012 were evaluated with the Mann-Kendall test, Theil-Sen approaches, Pettitt test, and Pearson's correlation. Stream flow was measured at the outlets of five major tributaries of Poyang Lake, while precipitation was recorded by fourteen meteorological stations located within the Poyang Lake Basin. Results showed that annual stream flow of all tributaries and the precipitation over the study area had insignificant (P > 0.1) temporal trends and change points, while significant trends and shifts were found in monthly scale. Stream flow concentration indices (SCI) at Waizhou, Meigang, and Wanjiabu stations showed significant (P < 0.05) decreasing trends with change points emerging in 1984 at Waizhou and 1978 at Wanjiabu, while there was no significant temporal trend and change point detected for the precipitation concentration indices (PCI). Correlation analysis indicated that area-average stream flow was closely related to area-average precipitation, but area-average SCI was insignificantly correlated with area-average PCI after change point (1984). El Niño/Southern Oscillation (ENSO) had greater impacts on stream flow than other climate indices, and La Niña events played a more important role in stream flow changes than EI Niño. Human activities, particularly in terms of reservoir constructions, largely altered the intra-annual distribution of stream flow but its effects on the amount of stream flow were relatively low. Results of this study provided a useful reference to regional water resource management and the prevention of flood and drought disasters. [ABSTRACT FROM AUTHOR]

One of the major challenges in hydrology consists in the conception of models to predict runoff evolution in time, as this is of crucial importance in water resource assessment and management. These models are required to provide estimations of high flows and low flows, so that appropriate short-term (flood) emergency measures and long-term (drought) management activities can be undertaken. However, due to the inherent nonlinearity of climate inputs (e.g. rainfall) and the heterogeneous nature of watersheds, understanding and modeling the catchment hydrologic response is tremendously challenging. This is particularly the case for karstic watersheds that are generally highly nonlinear and also sensitive to initial conditions. Investigation of the dynamic nature of hydrologic response is an important first step towards developing reliable models for such watersheds. To this end, this study examines the dynamic nature of streamflow discharge from karstic watersheds, especially the short-term variations. A nonlinear dynamic method, the correlation dimension method, is employed to unique long, continuous, and high-resolution (30-min) streamflow data from two karstic watersheds in the Pyrénées Mountains (Ariège) of France: the Aliou spring and the Baget spring. The results reveal the presence of deterministic chaos in the streamflow dynamics of the two watersheds, with attractor dimension values below 3. These results have great significance regarding the presence of deterministic chaos in karstic flows and in the issue of data size regarding chaos studies in hydrology. [ABSTRACT FROM AUTHOR]

Plains stream fishes in North America, including flathead chub Platygobio gracilis, are negatively affected by stream-flow alterations and fragmentation, and limited information on egg type and reproductive strategy hinders their conservation. On the basis of several lines of evidence, including laboratory culture, observations of reproduction in captivity, and capture and rearing of eggs from Fountain Creek, Colorado, we report that flathead chub produce nonadhesive eggs. Flathead chub eggs are relatively small at 2.3 mm mean diameter, have a greater yolk-to-egg volume ratio and thus sink faster, and take longer to hatch, compared with nonadhesive eggs from pelagic spawning species. Flathead chub are also longer lived compared with pelagic spawning species and the wider variety of habitat types they occupy may influence upstream egg retention. Although spawning mode (e.g., pelagic, lithopelagic, other) is incompletely known for flathead chub, habitat needs in terms of flows and reach lengths suitable for reproduction and recruitment may vary with habitat type but may be similar to that for other pelagic spawning species. Accommodating specialized reproductive life histories of fishes, including egg type and transport characteristics, in stream conservation planning may assist with maintaining or enhancing populations of all Great Plains cyprinids, including increasingly rare flathead chub. [ABSTRACT FROM AUTHOR]