Water Resources In Watershed Research Articles

Study of spatial distribution characteristics of river eco-environmental values based on emergy-GeoDa method

River eco-environmental value assessment is indispensable for the optimal allocation of watershed water resources. In this study, river eco-environmental values were divided into the values inside and outside the river based on the energy transfer and transformation of the water cycle. Their spatial distribution characteristics (spatial distribution map, spatial autocorrelation, and spatial aggregation) of 67 regions (states, leagues, and cities) in the Yellow River Basin (YRB) were analysed by combining emergy theory and GeoDa 1.14 software (emergy-GeoDa), and the significance of the results was tested. The results showed that: (1) the eco-environmental values inside the river were higher than those outside in the YRB, proving that eco-environmental water inside the river should be guaranteed and water consumption outside the river should not occupy water inside the river from the perspective of value; (2) the spatial distributions of eco-environmental values inside and outside the river were uneven, but obvious spatial aggregations were observed; (3) high- and low-value aggregations of eco-environmental values were observed inside the river in the lower and upper reaches of the YRB, respectively; (4) high- and low-value aggregations of eco-environmental values were observed outside the river in the middle and upper reaches of the YRB, respectively. It was suggested that ecological conservation and high-quality development should be considered as the goals for consolidating the river eco-environmental values in high-value areas and promoting in low-value areas, and low-value areas should be improved by high-value areas while allocating water resources in the YRB. These results provide suggestions for the sustainable development of river eco-environmental system in the YRB from a spatial perspective. In addition, the analysis method is also applicable for studying the spatial distribution characteristics of the values generated by the water and energy cycles of other regions.

Mineralization of water resources of Roc-Blanc watershed (Morocco)

Mineralization of water resources of Roc-Blanc watershed (Morocco)

Hydrogeophysical Characterization in a Volcanic Context From Local to Regional Scales Combining Airborne Electromagnetism and Magnetism

AbstractIn volcanic islands, a crucial step in managing watershed water resources is the characterization of groundwater aquifers from local to regional scales. Airborne geophysical data provide high‐resolution images down to hundreds of meters below the surface, over large areas. Yet, the production of an accurate interpretation of regional geophysical imagery may be time consuming or limited by the low density of geological and hydrological field observations. Here, we propose an approach combining airborne electromagnetic and magnetic data in order to reduce geophysical ambiguities and provide a multiscale hydrogeophysical characterization of Piton des Neiges volcano (Réunion Island). With limited calibration data, this methodology produces a geological model more accurate than using airborne electromagnetic data alone. Through the continuous coverage of both methods, we demonstrate the influence of volcanic unit geometries on groundwater flows within the critical zone and we highlight major structures impacting groundwater flows at both local and regional scales.

The assessment of annual rainfall field by applying different interpolation methods in the state of Rio Grande do Sul, Brazil

An accurate analysis of spatial rainfall distribution is of great importance for managing watershed water resources, in addition to giving support to meteorological studies and agricultural planning. This work compares the performance of two interpolation methods: Inverse distance weighted (IDW) and Kriging, in the analysis of annual rainfall spatial distribution. We use annual rainfall data for the state of Rio Grande do Sul (Brazil) from 1961 to 2017. To determine which proportion of the sample results in more accurate rainfall distribution maps, we use a certain amount of points close to the estimated point. We use mean squared error (MSE), coefficient of determination (R2), root mean squared error (RMSE) and modified Willmott's concordance index (md). We conduct random fields simulations study, and the performance of the geostatistics and classic methods for the exposed case was evaluated in terms of precision and accuracy obtained by Monte Carlo simulation to support the results. The results indicate that the co-ordinary Kriging interpolator showed better goodness of fit, assuming altitude as a covariate. We concluded that the geostatistical method of Kriging using nine closer points (50% of nearest neighbors) was the one that better represented annual rainfall spatial distribution in the state of Rio Grande do Sul.

Simulating trans-boundary watershed water resources conflict

With the rapid development of economy, the water shortage and water intake competition have been further intensified, resulting in the conflict of water resources development. This paper, against the amount of water conflict, has respectively constructed the three-party evolutionary game model regarding the water intake condition at the upper, middle and lower reaches of the river basin from the perspective of evolutionary game theory, verified the related conclusions with the numerical simulation. The conclusions of the research are as follows: (1) There are four sets of system local asymptotic stability points P20,0,1, P40,1,1,P61,0,1 and P81,1,1 in the three-party game of amount of water based trans-boundary water resources conflict, which means there existed four sets of evolutionary stable strategies (non-cooperation, non-cooperation, cooperation), (non-cooperation, cooperation, cooperation), (cooperation, non-cooperation, cooperation), and (cooperation, cooperation, cooperation). After the verification with the numerical simulation, the most contradictory area is existed between the upper and middle reaches of the river basin. Thus, the selected choice is (non-cooperation, non-cooperation, cooperation); (2) as for the amount of water based trans-boundary water resources conflict, the cost of cooperation water intake C1 has a significant impact on the strategy evolutionary path of the water intake group. This is of great theoretical and practical significance for the scientific regulation of trans-boundary water resources conflict and the realization of water resource management goals.

An Integrated Modeling System for the Evaluation of Water Resources in Coastal Agricultural Watersheds: Application in Almyros Basin, Thessaly, Greece

This study presents an integrated modeling system for the evaluation of the quantity and quality of water resources of coastal agricultural watersheds. The modeling system consists of coupled and interrelated models, including (i) a surface hydrology model (UTHBAL), (ii) a groundwater hydrology model (MODFLOW), (iii) a crop growth/nitrate leaching model (REPIC, an R-ArcGIS-based EPIC model), (iv) a groundwater contaminant transport model (MT3DMS), and (v) a groundwater seawater intrusion model (SEAWAT). The efficacy of the modeling system to simulate the quantity and quality of water resources has been applied to the Almyros basin in Thessaly, Greece. It is a coastal agricultural basin with irrigated and intensified agriculture facing serious groundwater problems, such as groundwater depletion, nitrate pollution, and seawater intrusion. Irrigation demands were estimated for the main crops cultivated in the area, based on precipitation and temperature from regional weather stations. The models have been calibrated and validated against time-series of observed crop yields, groundwater table observations, and observed concentrations of nitrates and chlorides. The results indicate that the modeling system simulates the water resources quantity and quality with increased accuracy. The proposed modeling system could be used as a tool for the simulation of water resources management and climate change scenarios.

Surface water – Groundwater Coupled Modelling for Watershed Water Resources Sustainability Assessment

There are limited studies in Cisangkuy Watershed which shows the water resources availability and variability with respect to changing climates and land use. Uncertainties due to climate change and population growth have created a critical water resources situation for Cisangkuy Watershed. These uncertainties come from undescribed quantification of surface water – groundwater interaction. Investigating spatio-temporal variability of recharge-discharge is a critical initial step for water-resource management. The main objective of this study is to set up a physically-based spatially distributed SWAT and MODFLOW for the analysis of the different hydrological and hydrogeological component. The objectives to be achieved include 1) identifying the characteristics and distribution of river stream recharge -discharge 2) assessing surface water and groundwater quantity. The result shows that calibrated SWAT-MODFLOW model can represent surface water – groundwater interaction in Cisangkuy Watershed spatio-temporally. Baseflow from aquifer discharge is main factor that give contribution to river discharge in study area, so we can conclude that Cisangkuy Watershed has a good potential of water resources on the low area, but also has high potential of disaster due to groundwater like flood and landslide.This study is expected to develop water resources management in Indonesia. So that water resources sustainability can be analyzed from the aspect of the quantity of surface water and groundwater.

Quantitative assessment of surface hydrological connectivity in Momoge National Nature Reserve, Northeast China

Quantitative assessment of hydrological connectivity is a hot but difficult issue in current research. Using the 30-m resolution global monthly surface water remote sensing dataset released by the EU Joint Research Center and three indicators of geostatistical connectivity, maximum distance of connection (MDC), and surface water extent of connectome (i.e., seasonally connected water bodies), we quantified the hydrological connectivity of surface water in Momoge National Nature Reserve in different months of a normal year (May to October 2016), and in September of different hydrological years (a wet year, namely 1998; a normal year, namely 2016; a drought year, namely 2002), and different directions (west-east and north-south). Our results showed that: 1) the geostatistical connectivity function (GCF) along the west-east direction was better than that along the north-south direction. The GCF in August and July was better than that in other months. The GCF along the west-east direction of each hydrological year was better than that in the drought year, whereas the GCF in the drought year was better than the corresponding value in the normal year. The GCF along the north-south direction in each hydrological year was better than that in the normal year, whereas the GCF in the normal year was better than that in the drought year. The MDC along the west-east direction in June, July, September, and October of the normal year was all concentrated at 25.26 km. MDC was more concentrated along the north-south direction, with 10 km for all months. The MDC in the normal and drought years was relatively close, but both were much smaller than that in the wet year. 2) frequent seasonal connections between the Yuelianghu Reservoir and the Nenjiang River, and between Etoupao and its neighboring lakes occurred in the study area during the normal year, while most of the other lakes remained isolated. The patterns of hydrological connection in the study area differed across different hydrological years: two giant connectomes were formed in the wet year, some lakes are periodically connected in the normal year, and all lakes remain isolated in the drought year. 3) As a drainage area for farmland receding water, the surface water extent of the Etoupao connectome increased visibly during the three water supplement seasons (spring, summer, and autumn). By quantifying the surface hydrological connectivity in Momoge National Nature Reserve with multiple water sources from different perspectives, our results provide a scientific basis for wetland protection and restoration and integrated management of watershed water resources.

Hydrological process simulation in Manas River Basin using CMADS

Abstract The inability to conduct hydrological simulations in areas that lack historical meteorological data is an important factor limiting the development of watershed models, understanding of watershed water resources, and ultimate development of effective sustainability policies. This study focuses on the Manas River Basin (MRB), which is a high-altitude area with no meteorological stations and is located on the northern slope of the Tianshan Mountains, northern China. The hydrological processes were simulated using the China Meteorological Assimilation Driving Datasets for the SWAT model (CMADS) using the Soil and Water Assessment Tool (SWAT) model. Simulated runoff was corrected using calibration/uncertainty and sensitivity program for the SWAT. Through parameter sensitivity analysis, parameter calibration, and verification, the Nash–Sutcliffe efficiency (NSE), adjusted R-square ( R adj 2 {R}_{\text{adj}}^{2} ), and percentage bias ( PBIAS \text{PBIAS} ) were selected for evaluation. The results were compared with statistics obtained from Kenswat Hydrological Station, where the monthly runoff simulation efficiency was NSE = 0.64 \text{NSE}\hspace{.25em}=0.64 , R adj 2 = 0.69 {R}_{\text{adj}}^{2}\hspace{.25em}=0.69 , and PBIAS = – 0.9 \text{PBIAS}\hspace{.25em}=\mbox{--}0.9 , and the daily runoff simulation efficiency was NSE = 0.75 \text{NSE}\hspace{.25em}=0.75 , R adj 2 {R}_{\text{adj}}^{2} = 0.75, PBIAS \text{PBIAS} = −1.5. These results indicate that by employing CMADS data, hydrological processes within the MRB can be adequately simulated. This finding is significant, as CMADS provide continuous temporal, detailed, and high-spatial-resolution meteorological data that can be used to build a hydrological model with adequate accuracy in areas that lack historical meteorological data.

Advances in Eco-hydrology and Watershed Water Resources Management in China

Advances in Eco-hydrology and Watershed Water Resources Management in China

Integrated Water Resources Research: Advancements in Understanding to Improve Future Sustainability

Anthropogenic and natural disturbances to freshwater quantity and quality is a greater issue for society than ever before. To successfully restore water resources in impaired watersheds requires understanding the interactions between hydrology, climate, land use, water quality, ecology, social and economic pressures. Current understanding of these interactions is limited primarily by a lack of innovation, investment, and interdisciplinary collaboration. This Special Issue of Water includes 18 articles broadly addressing investigative areas related to experimental study designs and modeling (n = 8), freshwater pollutants of concern (n = 7), and human dimensions of water use and management (n = 3). Results demonstrate the immense, globally transferable value of the experimental watershed approach, the relevance and critical importance of current integrated studies of pollutants of concern, and the imperative to include human sociological and economic processes in water resources investigations. Study results encourage cooperation, trust and innovation, between watershed stakeholders to reach common goals to improve and sustain the resource. The publications in this Special Issue are substantial; however, managers remain insufficiently informed to make best water resource decisions amidst combined influences of land use change, rapid ongoing human population growth, and changing environmental conditions. There is thus, a persistent need for further advancements in integrated and interdisciplinary research to improve scientific understanding, management and future sustainability of water resources.

Climate Change Induced Precipitation and Temperature Effects on Water Resources: the Case of Borkena Watershed in the Highlands of Wollo, Central Ethiopia

This study acquiring series issue of climate change which significantly affect the amount of precipitation and temperature at regional level, which intern would affect the water resources and future water availability of Borkena watershed located in the highlands of Wollo in Awash Basin, Ethiopia. Bias corrected Representative Concentration Pathways (RCP4.5 and RCP8.5) scenario data were used for precipitation and temperature projections in the 2050s. The projection result indicates mean annual precipitation increases at a rate of 14.70% and 13.21%; similarly, temperature increases by 1.16 °C and 1.59 °C, under both scenarios, respectively. After the projections of precipitation and temperature, Hydrological Modeling System (HEC-HMS) was used to simulate future streamflow and current evaporation estimated by Penman-Monteith while Hargreaves methods were used to estimate future evapotranspiration. The evaluation result showed that hydrological model is well performed for the watershed with daily R2 values 0.79 and 0.85 and Nash-Sutcliffe Efficiency (NSE) values 0.78 and 0.83 for calibration and validation periods, respectively. Results of this study present climate change induced temperature and precipitation changes significantly affect the monthly, seasonally, and annually evapotranspiration and streamflow of the watershed. The results show an increase in projected Potential Evapotranspiration (PET) at a rate of 2.77% and 3.20%; similarly, mean annual streamflow increases up to 22.63% and 14.57% under RCP4.5 and RCP8.5 scenarios, respectively. Seasonally, the mean streamflow during Kiremt and Bega expected to increase by 4.5% and 90.57% and 7.5% and 57.39%, but Belg season would decrease by 27.18% and 21.16% under RCP4.5 and RCP8.5 climate scenarios, respectively. These results are important to consider the influence of climate change on water resources of central Ethiopia, which is valuable for the planning and management of water resources in different watersheds of Ethiopia.

Modelling the Vegetation Response to Climate Changes in the Yarlung Zangbo River Basin Using Random Forest

Vegetation coverage variation may influence watershed water balance and water resource availability. Yarlung Zangbo River, the longest river on the Tibetan Plateau, has high spatial heterogeneity in vegetation coverage and is the main freshwater resource of local residents and downstream countries. In this study, we proposed a model based on random forest (RF) to predict the Normalized Difference Vegetation Index (NDVI) of the Yarlung Zangbo River Basin and explore its relationship with climatic factors. High-resolution datasets of NDVI and monthly meteorological observation data from 2000 to 2015 were used to calibrate and validate the proposed model. The proposed model was then compared with artificial neural network and support vector machine models, and principal component analysis and partial correlation analysis were also used for predictor selection of artificial neural network and support vector machine models for comparative study. The results show that RF had the highest model efficiency among the compared models. The Nash–Sutcliffe coefficients of the proposed model in the calibration period and verification period were all higher than 0.8 for the five subzones; this indicated that the proposed model can successfully simulate the relationship between the NDVI and climatic factors. By using built-in variable importance evaluation, RF chose appropriate predictor combinations without principle component analysis or partial correlation analysis. Our research is valuable because it can be integrated into water resource management and elucidates ecological processes in Yarlung Zangbo River Basin.

Evaluating the Risks of Groundwater Extraction in an Agricultural Landscape under Different Climate Projections

Groundwater resources worldwide are being depleted at alarming rates since 1960 to support agriculture, industry, and domestic water demand. Water harvesting and the implementation of reduced application or more efficient irrigation technologies were identified as two of the most efficient practices to mitigate the declining patterns on groundwater resources. However, prior to implementing these practices, understanding how groundwater interacts with surface water and responds to natural and anthropogenic stressors is crucial. Integrated modeling tools that are able to exchange fluxes in both domains are needed to assess how conservation practices will affect our water resources under different projected climate and land use scenarios. This study aimed to evaluate the most likely impacts of current land management practices under the most severe projections of future climate and quantify the potential mitigation effects of three conservation scenarios on the water resources of the Fort Cobb Reservoir Experimental Watershed (FCREW) in western Oklahoma. The semicoupled SWAT-MODFLOW (SWATmf) model was used to simulate the hydrologic responses of the FCREW to a 50% reduction in the irrigation depths and the transition of 50% and 75% of croplands to rangelands under 32 distinct climate projections. Results showed that future climate can drive a reduction in the streamflow (−18%) and an increase to the depth of the water table (99%–120%) in the western part of the FCREW by the end of the century. The Fort Cobb Reservoir was expected to reduce its release after the mid-2060s to maintain its current target level. All the scenarios, aimed at decreasing groundwater extractions or implementing conservation measures, signaled a full recovery response in the groundwater levels 7–10 years after the year the conservation practices were implemented. The 50% reduction in the irrigation depths was found to elicit faster hydrologic systemic responses than the two that implemented conservation measures, which contravene tradition and would imply cessation of agricultural activities. This study can enable stakeholders to formulate timely adaptation and mitigating strategies to adopt to land use changes.

Impact of Meteorological Drought on Streamflows in the Lobo River Catchment at Nibéhibé, Côte d’Ivoire

The management of water resources in watersheds has become increasingly difficult in recent years due to the frequency and intensity of drought sequences. The Lobo River catchment, like most tropical regions, has experienced alternating wet and dry periods. These drought periods have a significant impact on the availability of water resources in the basin. The objective of this study is to analyse the impact of meteorological drought on flows in the Lobo River catchment. Therefore, using the Normalized Precipitation and Evapotranspiration Index (SPEI) and the Drought Flow Index (SDI), the characteristics of droughts were studied. The results of this study show that meteorological droughts were more frequent than hydrological droughts in the Lobo River watershed. However, the hydrological drought was longer and more intense than the meteorological drought. The greater relationship between meteorological and hydrological drought was observed at the Daloa and Vavoua station (0.43 < r < 0.50) compared to the Zuenoula station (r < 0.5). In addition, there was a resumption of precipitation and runoff between 2007 and 2013 in the basin. The study of these climatic trends would be very useful in the choice of management and adaptation policies for water resources management.

An overview of research into conservation practice effects on soil and water resources in the Upper Washita Basin, Oklahoma, United States

The Fort Cobb Reservoir Experimental Watershed (FCREW) and Little Washita River Experimental Watershed (LWREW), located within the Upper Washita Basin (UWB) in Oklahoma, are part of the Agricultural Research Service (ARS) Benchmark Conservation Effects Assessment Project (CEAP)–Watershed Assessment Studies locations. The CEAP was created in 2003 by the USDA Natural Resources Conservation Service (NRCS) in partnership with USDA ARS and many other partners to quantify the environmental effects of conservation practices (CPs) and programs and to develop the science base for managing the agricultural landscape for environmental quality. The ultimate goal of this study was to present CPs that are expected to work at respective spatial scales, based on the findings of research that has been carried out in these CEAP and other watersheds within the UWB in the last 15 years. A summary of research findings indicates that the effects of CPs on soil and water resources were simulated at various spatial scales. At the large watershed scale, average annual suspended sediment yield at the 786 km² (303 mi²) FCREW outlet was reduced by 86% based on multiple CPs implemented from the 1950s to 2008 by NRCS. Specific quantified effects of studied CPs are presented herein. With the exception of red cedar (<i>Juniperus virginiana</i> L.) removal, single CPs were expected to show improvement of soil and water resources in smaller-scale watersheds. Practices that are expected to improve soil and water resources include grassland conservation from red cedar encroachment (brush control), combined streambank stabilization practices, riparian and filter strip buffer practices, and conversion of cropped area to Bermuda grass (<i>Cynodon dactylon</i> [L.] Pers.).

Are multiple multimetric indices effective for assessing ecological condition in tropical basins?

Abstract The quality and availability of water resources in tropical watersheds are threatened by increased multiple use demands by human populations. Therefore, there is a need for cost-effective ecological indicators of water body status and trends. Multimetric indices (MMIs), based on responses of biological assemblages to anthropogenic disturbances, are excellent examples of such indicators and they have been applied globally. However, creating new MMIs for each water body or study area requires considerable analytical effort and hinders our ability to make regional or global comparisons. Therefore, we tested the effectiveness of 17 published benthic macroinvertebrate MMIs for assessing the environmental quality of a tropical anthropogenically least-disturbed river basin in the Neotropical Savanna (Brazilian Cerrado) biome. We tested those MMIs through use of macroinvertebrate data sampled at 40 stream sites in the Pandeiros River basin, Brazil. Disturbances in the basin were related to local factors such as pasture, garbage, and cropland in stream riparian areas. Index performance was tested by comparing precision, bias, responsiveness and sensitivity to anthropogenic pressures and stressors. Ten indices performed satisfactorily in evaluating the environmental condition of the basin. Therefore, we do not recommend developing new benthic MMIs for rapid environmental quality assessments. On the other hand, we do recommend using standard data collection methods for evaluating conditions throughout the biome.

Precipitation Trends and Alteration in Wei River Basin: Implication for Water Resources Management in the Transitional Zone between Plain and Loess Plateau, China

Precipitation plays a critical role in water resources management, and trend changes and alterations thereof are crucial to regional or basin water security, disaster prevention, and ecological restoration under a changing environment. In order to explore the implications of precipitation variation for water resources management, taking the Wei River Basin (a transitional zone between the Guanzhong Plain and Loess Plateau) as an example, this paper proposes an index system, namely the index of precipitation alteration (IPA), to evaluate changes in precipitation and investigate their potential influence on water resources management. The system includes 17 indicators gained from observed daily rainfall, involving some structural precipitation indicators describing the precipitation patterns and some functional precipitation indicators influencing utilization of watershed water resources. Non-parametric Mann-Kendall (MK) statistical test is employed to identify the IPA trend change, and range of variability approach is used to evaluate the variation of IPA. The analysis results in Wei River Basin show that IPA varies with different spatial and temporal distributions. Overall, although the annual total precipitation declined in the study area, the frequency of extreme events was increased during 1955–2012. In the face of severe climate change patterns, it is necessary to establish the precipitation index to evaluate the change of precipitation and to provide useful information for future precipitation assessments.

The Runoff Evolution and the Differences Analysis of the Causes of Runoff Change in Different Regions: A Case of the Weihe River Basin, Northern China

The runoff levels of the major hydrological stations in the Weihe river basin (WRB) have been found to present decreasing trends. However, the conspicuous spatial differences in the hydro-meteorological conditions have led to variations in the rainfall–runoff pattern in each of the sub-basin areas. The aims of this research study were to reveal the main factors contributing to the runoff changes in the different regions—and it has significance in the water resources rational allocation and protection in the different regions. Three statistical methods were used to analyze the law of precipitation and runoffs of five hydrological stations. The SWAT (Soil and Water Assessment Tool) model was used to reconstruct the runoff in the impact period. The effects of climate change and human activity on runoff were separated by comparing measured runoff and reconstructed runoff. The results show that the closer the proximity to the downstream hydrological station, the more the runoff decreased. In the tributaries and upstream hydrological stations (Zhuanhtou (ZT), Zhangjiashan (ZJS), and Linjiacun (LJC)), from 1970 to 2016, the dominant factor of the runoff reduction was determined to be climate change, and accounted for 148.2%, 98.9%, and 90.5%, respectively. In the hydrological stations of middle and lower reaches (Xianyang (XY) and Huaxian (HX)), the contributions of the climate change to the runoff reduction were 49.7% and 44.3%, respectively, and the impacts of human activity accounted for 50.3% and 55.7%. The impacts of human activity on the runoff reduction were slightly greater than that of the climate change. Due to the different leading factors affecting runoff change in the basin, in response to future climate change, for tributaries and upstream areas, land use should be rationally planned to achieve the optimal balance of water volume in each part of the basin, which is of great significance to the protection and utilization of water resources. As for the middle and downstream regions, reasonable planning should also be focused on the amount of water withdraw, water resource allocations, and water conservancy project construction. According to the factors affecting runoff, corresponding strategies are proposed for different regions, which have important research significance for the protection and sustainable development of watershed water resources.

A new intelligent method for monthly streamflow prediction: hybrid wavelet support vector regression based on grey wolf optimizer (WSVR–GWO)

Forecasting daily and monthly streamflows is necessary for short- and long-term water resources management, particularly in extreme cases, e.g., flood and drought. Accurate models are needed to plan and manage water resources in watersheds. Recently, support vector regression (SVR) shows the ability to handle the hydrological forecasting issues, but the accuracy of SVR depends on the appropriate choice of parameters and selection of proper inputs. A new meta-heuristic algorithm called grey wolf optimizer (GWO) is used in the current research in order to improve SVR accuracy in forecasting monthly streamflow. The proposed approach is compared with other evolutionary methods, particle swarm optimization, shuffled complex evolution, and multi-verse optimization, that are employed in tuning SVR parameters. Furthermore, the proposed methods were also combined with wavelet transform and tested using monthly streamflow data from two gauging stations, Ain Bedra and Fermatou, in Algeria. To assess the performance of the developed models, Nash–Sutcliffe efficiency (NSE), correlation coefficient, root mean squared error (RMSE), and mean absolute error (MAE) were used. The obtained results indicate that multi-linear regression provides appropriate input variables to SVR models. According to all of the performance measures used, hybrid models exhibit better performances, in monthly streamflow prediction, compared with single versions. For example, for the Ain Bedra station, the NSEcriterion and the correlation coefficient values increased considerably from 27.36% and 0.5405, for the single models, to 95.72% and 0.9786, for the hybrid models. A great decrease has also been obtained for the RMSE and MAE values, which decreased from 0.1562 m3/s and 0.1244 m3/s to 0.6433m3/s and 0.3047 m3/s. In addition, the new GWO algorithm outperformed the other algorithms in terms of both forecasting accuracy and convergence.