Soil Water Assessment Tool Research Articles

Forecasting 100-year changes of streamflow in the Mun River Basin (NE Thailand) under the HAPPI experiment using the SWAT model

Abstract The Lower Mekong River is one of the significant rivers nurturing people on the Southeast Asian mainland. Its tributaries include the Mun River (NE Thailand), which often experiences extreme water events. In this study, the streamflow change in the year 2115 was simulated by relying on the Half a degree Additional warming, Prognosis and Projected Impacts (HAPPI) experiment and the Model for Interdisciplinary Research on Climate, version 5 (MIROC5) climate model for average global warming of 1.5 °C (Plus1.5) and 2.0 °C (Plus2.0) above pre-industrial levels and compared with the base year in 2015 for the Mun River Basin. The Soil–Water Assessment Tool (SWAT) was used for the streamflow simulation. The results showed an increasing air temperature against lowering rainfall and relative humidity (except for the post-monsoon months), suggesting overall rain suppression in response to the warming climate. The median projected annual streamflow to the Mekong River in 2115 decreased for both ‘Plus1.5’ (−32.5%, median) and ‘Plus2.0’ (−23.1%, median). However, increasing annual streamflow could be found only in the middle part. Seasonal streamflow changes revealed a different spatiotemporal response to climate change resulting in inconsistent streamflow changes across the basin. The adaptive measures for the middle part should be focused on flooding control, whereas the upper and the lower parts should be against drought.

Impacts of climate and land use change on groundwater recharge under shared socioeconomic pathways: A case of Siem Reap, Cambodia

The rapid pace of urbanization blended with climate change has significantly altered surface and groundwater flows. In the context of tourism-driven economic potential areas, these drivers have greater effects, including threatening groundwater availability. This study assessed the combined impacts of climate and land use changes on the groundwater recharge (GWR) in Siem Reap, Cambodia utilizing Phase Six of the Coupled Model Intercomparison Project (CMIP6) global climate models (GCMs), DynaCLUE land-use model, and Soil Water Assessment Tool (SWAT). Three climate models CanESM5, EC_Earth3, and MIROC6, out of seven, best captured the observed data after performance evaluation through the entropy method, were bias-corrected linearly for two shared socioeconomic pathways (SSPs) - SSP2-4.5 and SSP5-8.5. The results indicate a general increase in precipitation under both SSPs, while the average annual maximum temperature is likely to increase by 0.024 °C/year and 0.049 °C/year under SSP2-4.5 and SSP5-8.5, respectively. A similar trend but relatively higher increase is expected for the minimum temperature. Furthermore, the historical land use change showed the expansion of urban settlement by 373% between 2004 and 2019 at the expense of forest and shrubland. Future land use projections from the DynaCLUE model show that the urban settlements in the study area are likely to expand, from their 2019 condition, by 55% in 2030, 209% in 2060, and 369% in 2090 under SSP2 and at double of these rates under SSP5 scenario. The GWR is expected to rise by 39–53% during the wet season and decrease by 13–29% during the dry season under both scenarios. Meanwhile, under constant land use, the GWR is likely to increase more compared to other scenarios, highlighting the importance of land use planning to policymakers and planners. Additionally, the study shall also be important to practitioners and researchers in understanding, planning, and evaluating the performance of multiple climate models in groundwater assessment.

Hydrological modeling of hydrographic basin in the northeast semiarid region of Brazil

The use of hydrological models allows to understand, evaluate and anticipate events of natural or man-made origin in a simpler and more economical way for the quantity and quality of resources in a hydrographic basin. The present work aims to perform a hydrological modeling in the hydrographic basin in the semiarid, using the SWAT model, to verify the influence of the use and exploitation of water production on the land. For this, the SWAT hydrological model (Soil Water Assessment Tool) was used. A study area located in the Jacaré Curitiba Basin, in Poço Redondo-SE, a semi-arid region of the state, inserted in the Caatinga biome and in the lower São Francisco. The adopted methodology was used for bibliographic survey, field work, hydrological monitoring, chemical and physical medicine of soil and soil, survey of land use and exploration, calibration and validation of hydrological model. The SWAT model successfully simulated or hydrographed the flow for the period from Nov/2015 to Jul/2018, duly calibrated and validated. As simulations of different land use scenarios, the greatest production of water in agricultural areas stands out, which can cause greater generation of sediments. The calibrated and validated SWAT model means a possibility for future studies in non-semiarid watersheds and then contributes to studies on water and soil management.

No-tillage implementation: Analyzis on water-based sediment flow in the Marombas River, Brazil

ABSTRACT Water erosion is influenced by climate, soil, soil cover and soil conservation practices. These factors can be modified by natural (especially climate) and/or anthropogenic (especially soil, soil cover and conservation practices) actions. The relief factor also influences the water erosion and can also be partially modified by anthropic action. This study aimed to evaluate the impact of anthropogenic action due to the introduction of soil crop in no-tillage system on water erosion, and on the consequent flow of sediments in the water. The study was carried out in the Marombas river basin with an area of 3,939 km², using the Soil Water Assessment Tools (SWAT) model. The calibration and validation of the model for sediment production was carried out with a historical series of synthetic data. The data from this series were estimated by linear regression from sediment value load and the average daily flow obtained punctually in the basin’s outlet. The SWAT model was calibrated on a daily scale with data from 1979 to 1989 and was validated with data from 1994 and 1997. The SWAT model was suitable to represent the average daily flow and sediment flow in the Marombas watershed. The hypothesis of reduced sediment production with increasing soil crop in no-tillage system was accepted.

Multivariate drought analysis for the temperature homogeneous regions of India: Lessons from the Gomati River basin

AbstractDroughts inflict significant loss on agricultural economies. Gomati River basin, the area of the present study, is located within the Ganga River floodplains, which approximately coincide with the north central temperature homogeneous region (NCTHR) of India. Gomati basin is a non‐perennial one supporting water intensive agricultural crops. To ascertain the occurrence of droughts (if any) from 1986 to 2015 within Gomati River basin, in terms of inter‐dependencies of drought causing variables through study of multivariate drought indices, is the main objective of the present study. Soil Water Assessment Tool (SWAT) was used in combination with the Copula approach to construct multivariate standardized drought indices (MSDIs) for drought onset detection through simulation in the face of data scarcity. Although MSDI based assessment of the basin as a whole did not detect any droughts, in the upper basin, MSDIs indicated the possibilities of impending agricultural droughts marked by their consistent variability aroundnear‐normalconditions. This methodology can be used to detect drought situations in data scarce non‐perennial river basins within the Ganga River floodplains including the NCTHR of India.

딥러닝 알고리즘의 성능을 향상하기 위한 최적 모니터링 주기 결정: 남강 유역의 사례를 중심으로

The intention of this study is to address the effect of temporal resolution of input data on the prediction accuracy of deep learning algorithms. A popular watershed model Soil & Water Assessment Tool (SWAT) was used to generate time series of discharge and 9 water quality variables over different time intervals (i.e., 1, 2, 3, and 7 days) for three years (i.e., 2015-2017). We then assessed the performance of two deep learning algorithms, recurrent neural network (RNN) and gated recurrent unit (GRU), on those prepared data sets. Our finding showed that the prediction accuracy of the RNN algorithm increased progressively with the time resolution of input data from weekly data to daily data. The RNN also achieved its superior performance on the daily data, regardless of dependent variables. The only exception was the variable carbonaceous biochemical oxygen demand. When a comparison was made between those algorithms, the RNN algorithm was found to have slightly better accuracy than the GRU algorithm. Collectively, all these results revealed that the temporal resolution of input data was strongly responsible for changes in the performance of deep learning, specifically for those used in time series prediction.

Watershed-scale modelling of the irrigated rice farming system at Muda, Malaysia, using the Soil Water Assessment Tool

ABSTRACT Agricultural production in a highly managed watershed is challenging to capture in models due to its complexity and large hydrological, management, and crop data requirements. We evaluated hydro-crop simulation of Malaysia’s largest rice granary using the Soil Water Assessment Tool (SWAT). The 4515 km2 watershed is characterized by dams in the upper sub-watersheds that drain towards 1007 km2 of rice paddies. Monthly averaged streamflow simulation produced Nash-Sutcliffe efficiencies and coefficients of determination between 0.84 and 0.90 in both calibration and validation periods. Meanwhile, the normalized root mean square error and the percent bias for rice yield simulation in off and main seasons of rice planting were within ± 10%. Investigation of rice yield loss processes revealed a stronger control by solar radiation on crop growth processes compared to other hydroclimatic and environmental stresses. Our findings show that SWAT can reliably simulate streamflow and rice growth; however, it may not capture all yield loss processes.

Simulating Discharge in a Non-Dammed River of Southeastern South America Using SWAT Model

Within a single region, it is possible to identify opposite changes in flow production. This proved to be the case for several basins in southeastern South America. It remains challenging to the causes this behavior and whether changes in streamflow will continue at current levels or decline in the coming decades. In this study, we used the Soil Water Assessment Tool to simulate monthly river discharge in the Ivaí River Basin, an unregulated medium-sized catchment and tributary of the Upper Paraná River Basin. After calibration, the simulated flow regime for the five streamflow stations based on the Nash-Sutcliffe Efficiency index (NSE) rated four of the streamflow stations Very Good (NSE between 0.86 and 0.89) and only one in the Good index (0.70). The overall flow behavior was well represented, although an underestimation was identified in four monitoring stations. Through assessment of its functionality and limitations in terms of specific flow duration curves percentages, the calibrated model could provide (to managers) the reliability needed for a realistic intervention. The results of this study may assist managers and support public policies for the use of water resources at the Ivaí River basin.

Pi-VAT: A web-based visualization tool for decision support using spatially complex water quality model outputs

Effective watershed management and protection of water resources from non-point source pollution require identification, prioritization, and targeting of pollutant source areas. Process-based hydrology and water quality models are powerful heuristic tools for land and water resources managers. However, because of their complexity, such models are often under-utilized as management prioritization and planning tools. In this paper, we present a prioritization, interactive visualization, and analysis tool (Pi-VAT) that is programmed to synthesize multi-scenario, multi-watershed outputs from process-based geospatial models. We demonstrate the utility of Pi-VAT to examine simulated hydrologic, sediment, and water quality response at the hillslope/hydrologic response unit (HRU) scale. We apply Pi-VAT to output from multiple watersheds and for multiple management scenarios and treatments from two geospatial models for watershed management: Water Erosion Prediction Project (WEPP) and Soil & Water Assessment Tool (SWAT). Pi-VAT was developed using the Shiny web application framework for the R programming language. In a matter of minutes, Pi-VAT can synthesize overwhelming amounts of output from process-based models into information useful for land and water resources managers. We illustrate the use of Pi-VAT to interactively identify, quantify, and visualize areas that are most susceptible to disturbance under different scenarios and provide a synthesis approach based on land use, soil type, and slope steepness. This approach guides land and water resources managers in prioritizing the areas of the watershed that provide the maximum reduction in pollutant loads while treating the least amount of area. Pi-VAT provides a flexible reactive platform for the development of decision support tools based on process-based models intended for watershed management and research applications.

Impacts of Soil Information on Process-Based Hydrological Modelling in the Upper Goukou Catchment, South Africa

Although soils form an integral part of landscape hydrological processes, the importance of soil information in hydrological modelling is often neglected. This study investigated the impact of soil information on streamflow modelling accuracy and hydrological process representation. Two different levels of soil information were compared to long-term streamflow in the upper Goukou catchment (230 km2), South Africa, over a period of 23 years using the Soil Water Assessment Tool (SWAT+). The land-type soil map (LTSM) dataset was less detailed and derived from the best, readily available soil dataset for South Africa currently. The hydrological soil map (HSM) dataset was more detailed and was created using infield hydropedological soil observations combined with digital soil-mapping techniques. Monthly streamflow simulation was similar for both soil datasets, with Nash–Sutcliffe efficiency and Kling–Gupta efficiency values of 0.57 and 0.59 (HSM) and 0.56 and 0.60 (LTSM), respectively. It is, however, important to assess through which hydrological processes were these streamflow values generated as well as their spatial distribution within the catchment. Upon further assessment, the representation of hydrological processes within the catchment differed greatly between the two datasets, with the HSM more accurately representing the internal hydrological processes, as it was based on infield observations. It was concluded that hydropedological information could be of great value in effective catchment management strategies since it improves representation of internal catchment processes.

Water and sediment yield estimation: A case study in Bawashaswar Watershed/ Iraqi Kurdistan Region

Water flow in the seasonal streams forms a vital supplier of water resources, particularly in arid and semiarid areas due to its high-water supply from the precipitation during the wet season. This research aims to estimate water and sediment yield in the Bawashaswar watershed, which is far ~90 km from Kirkuk City. It has a semiarid climate and covers an area of 277 km2. The Bawashaswar Dam was constructed —for multi-purposes such as drinking, irrigation, livestock, and tourism— at the outlet of the watershed north of Kifri town. This study aims to give valuable data and information about water and sediment yield within the watershed of the Bawashaswar Dam and the possibility of the investment of the water for the above purposes. The Soil Water Assessment Tool (SWAT) was integrated with several datasets (such as satellite images, Digital Elevation Model (DEM), land use, land cover, curve number (CN), daily climatic data of temperature, precipitation, and digital soil map) to achieve the results. The estimated results include precipitation, evaporation- transpiration, percolation, surface runoff, water yield, loss of transport, and sediment yield. The results showed that almost all the siltation (>0.5 ton/ha) comes from the western and northern parts of the Bawashaswar Watershed due to the high topographic relief and the high channel discharge there. These results will support the future development plans and management of the watershed through mitigating and minimizing the size of the ground surface degradation problems all over the study area with increasing the lifespan of the Bawashaswar Dam.

基于历史参照系的三江源区径流调节功能及变化评估

PDF HTML阅读 XML下载 导出引用 引用提醒 基于历史参照系的三江源区径流调节功能及变化评估 DOI: 10.5846/stxb202104100930 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点研发计划项目（2016YFC0500205） Assessment of runoff regulation function and its change in the Three Headwater Region based on a historical reference system Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:以20世纪70年代植被类型图作为参照生态系统，采用径流量和径流系数作为径流调节功能的表征指标，建立了基于历史参照系的三江源区径流调节功能评估模型，以参照系径流系数与实际径流系数的比值作为径流系数质量指数，分析了2000-2017年三江源区生态系统径流调节功能参照值、现状值及变化量的时空变化规律。结果表明：2000-2017年，三江源区多年平均径流量为495.15亿m3，地表径流量为96.64亿m3，参照系条件下多年平均径流量为468.37亿m3，地表径流量为68.60亿m3。相比参照系，三江源区生态系统的径流蓄纳能力降低，总径流量和地表径流量均明显增加。空间上，基于参照系和实际生态系统的多年平均径流量表现为东南高西北低的空间分布特征，地表径流量则呈西部高东部低的空间分布特征。从时间变化看，实际径流和参照系径流的差别率在4%-9%之间，实际地表径流和参照系地表径流的差别率在22%-58%之间。径流系数质量指数得分显示，2000-2017年，三江源区径流系数质量指数平均得分为98.63，地表径流系数质量指数平均得分为96.98，两者均呈现先降低后增加的趋势，地表径流系数质量指数变化更为明显。2000-2017年，各县（镇）径流系数和地表径流系数质量指数得分具有较大差别，但各县（镇）得分变化均不明显，变化率分别在-1.95%-0.71%和-0.35%-1.90%之间。通过建立基于历史生态系统的评估参照系，定量评估了三江源区参照系和实际条件下的径流变化过程，实现了不同时间、不同区域生态系统径流调节功能的可比较，可对量化生态系统恢复进程提供支撑。 Abstract:By taking the vegetation map in the 1970s a reference ecosystem and using runoff volume and runoff coefficient as the characteristic indexes of ecosystem runoff regulation function, a runoff regulation function evaluation model based on the SWAT (Soil & Water Assessment Tool) model and a historical reference system was established. Then, the temporal and spatial variation characteristics of runoff regulation function in the Three Headwater Region from 2000 to 2017 were analyzed. Besides, the ratio of the reference runoff coefficient to the actual runoff coefficient was used as the runoff coefficient quality index to describe the deviations of the actual ecosystem from the reference system, for further analysis of the variation characteristics of runoff deviations between the reference ecosystem and the actual ecosystem. Results showed that, between 2000 and 2017, the perennial average runoff and surface runoff were 495.15×108 m3 and 96.64×108 m3, and the perennial average reference runoff and surface runoff were 468.37×108 m3 and 68.60×108 m3. Compared with the reference ecosystem, the runoff storage capacity of ecosystem decreased, resulting in higher runoff and surface runoff. Spatially, the runoff was high in the southeast and low in the northwest, but surface runoff was high in the west and low in the east whether under the reference or actual ecosystems. In terms of the interannual change, we found a visible increase of runoff, especially surface runoff under the actual ecosystem. The difference rate between the actual runoff and the reference runoff ranged from 4% to 9%, and it showed a more pronounced deviation of 22% to 58% of surface runoff. Fro the runoff coefficient quality index score, the average score of runoff coefficient quality index was 98.63, and the average score of surface runoff coefficient quality index was 96.98 in 2000-2017 in the Three Headwater Region. Generally, both scores showed a trend of first decreasing and then increasing, indicating a process of degradation and then recovery during this period, and the change of surface runoff coefficient quality index was more obvious. The scores of runoff coefficient quality index and surface runoff coefficient quality index varied greatly among regions, but the interannual changes were small, with a change of -1.95% to 0.71%, and a change of -0.35% to 1.90%. By analyzing the temporal and spatial variation characteristics of runoff regulation function based on a historical reference system, the comparison of runoff regulation functions in different ecosystems at different times and in different regions was realized, which could provide support for quantifying the process of ecosystem restoration. 参考文献 相似文献 引证文献

Calibration and validation of soil water assessment tool for Poondi Micro-Watershed

Calibration and validation of soil water assessment tool for Poondi Micro-Watershed

Application of Soil Water Assessment Tool (SWAT) Model in Analyzing Nitrogen Transport Inside the Narmada River Basin

The Narmada River is one of the largest rivers in Western India encompassing a watershed area of 92,672 km2. It is one of the most important rivers for water needs of the state of Gujarat, Maharashtra, and Madhya Pradesh. The climate of the basin is humid and tropical but region surrounding this river watershed is predominantly dry and resembles semi-arid conditions. The population inside the states covering this watershed increased by an average of 23% from 1991 to 2011 causing multitude of water scarcity and water quality deterioration issues. These problems were caused by increase in sewage waste and untreated industrial discharge dumped into the river stream along with chemical fertilizers washing off from the farmlands flowing into the river. While there are several studies that model the watershed hydrology and water balance components, there has been no study that analyses the transport of nutrients inside the watershed. This study aims at using a semi-distributed hydrological model—Soil Water Assessment Tool (SWAT) to model the nitrogen (NO2 + NO3) transport and distribution inside the basin for 2001–2019. Nutrients and discharge data from Central Water Commission (CWC) of India were used to build this model along with other required input forcing obtained through remotely sensed datasets. We found that the subbasins near boundary of the Narmada watershed are experiencing significant increase in nitrogen concentrations at an estimated rate of 0.0001–0.002 mg/L/yr. The potential reason for such increase is high rate of conversion of forested land to agricultural land causing usage of fertilizers that are rich in nitrogen.

Improvements in Sub-Catchment Fractional Snowpack and Snowmelt Parameterizations and Hydrologic Modeling for Climate Change Assessments in the Western Himalayas

The present work proposes to improve estimates of snowpack and snowmelt and their assessment in the steep Himalayan ranges at the sub-catchment scale. Temporal variability of streamflow and the associated distribution of accumulated snow in catchments with glacier presence in the Himalayas illustrates how changes in snowpack and snowmelt can affect the water supply for local water management. The primary objective of this study is to assess the role of elevation, temperature lapse rate (TLR), and precipitation lapse rate (PLR) in the computation of snowpack (or snowfall) and snowmelt in sub-catchments of the Satluj River basin. Modeling of snowpack and snowmelt was constructed using the Soil Water Assessment Tool (SWAT) in both historical (1991–2008) and near-time scenarios (2011–2030) by implementing real-time hydrometeorological, snow-hydrological parameters, and Global Circulation Model (GCM) datasets. The modeled snowmelt-induced streamflow showed a good agreement with the observed streamflow (~60%), calibrated and validated at three gauges. A Sequential Uncertainty Parameter Fitting (SUFI2) method (SUFI2) resulted that the curve number (CN2) was found to be significantly sensitive during calibration. The snowmelt hydrological parameters such as snowmelt factor maximum (SMFMX) and snow coverage (SNO50COV) significantly affected objective functions, such as R2 and NSE, during the model optimization. For the validation of snowpack and snowmelt, the results have been contrasted with previous studies and found comparable. The computed snowpack and snowmelt were found highly variable over the Himalayan sub-catchments, as also reported by previous researchers. The magnitude of snowpack change consistently decreases across all the sub-catchments of the Satluj river catchment (varying between 4% and 42%). The highest percentage of changes in the snowpack was observed over high-elevation sub-catchments.

Flow Simulation and Storage Assessment in an Ungauged Irrigation Tank Cascade System Using the SWAT Model

In the semi-arid regions of South Asia, tank systems are the major source of irrigation. In India, the Telangana state government has initiated the Mission Kakatiya program to rejuvenate irrigation tank systems. Understanding the hydrological processes that supply water to these systems is critical to the success of these types of programs in India. The current study attempted to comprehend the hydrological processes and flow routing in the Salivagu watershed tank cascade system in Telangana. There are a lot of ungauged tank cascade systems in this region. Soil Water Assessment Tool (SWAT), a physically-based model, was used to simulate flow patterns in the Salivagu watershed with and without tank systems. The geospatially extracted area and volume were used for this study provided by WBIS-Bhuvan-NRSC. Additionally, the Katakshapur Tank Cascade System (KTCS) was chosen to analyze the water availability in each tank using the water balance approach. The Salivagu watershed flow simulation without tanks overestimated streamflow. The volume difference in flow between with and without tank was 606 Mm3, 615.9 Mm3, and 1011 Mm3 in 2017, 2018, and 2019, respectively. The SWAT simulated volumes of the Ramchandrapur and Dharmaraopalle tanks in KTCS were merely satisfied because the tank size was less than 0.7 km2 and the storage capacity was up to 1 Mm3. Due to tank sizes more than 0.8 km2 and capacities greater than 2 Mm3, the Mallampalli and Katakshapur tank simulation findings were in good agreement with WBIS-Bhuvan-NRSC. This research advances our understanding of the hydrological processes in ungauged cascading tank systems in tropical semi-arid regions.

Modeling the effects of human influences on water quality and quantity in the Zarrineh River Basin, Iran

This study aims to analyze the environmental and economic impacts of land use change and water abstraction in the Zarrineh River basin, which is Lake Urmia’s main inflow source in the north-west of Iran. The Soil & Water Assessment Tool (SWAT) is used to model water quantity and quality in the basin. Environmental Kuznets Curves (EKC) are used to assess the relationship between environmental degradation and the development of the agricultural sector. Two scenarios were employed to identify the effects of dam construction and land use change on stream flow, evapotranspiration, groundwater recharge and nitrate loads in the area. The SWAT model showed a satisfactory to very good performance for monthly stream flow at most of the gauges in calibration and validation periods as well as a reasonable performance for nitrate loads. The estimated EKC indicates that the environmental degradation in the inverted U-shape that has passed its peak and the rate of degradation has decreased. Based on the scenarios, the dam has a strong impact on nitrate loads in the basin and water inflow into Lake Urmia. Results verify that human influences have had negative impacts on the Zarrineh River basin. In particular, the extensive development of the agricultural sector has not only drastically reduced the inflow of water to Lake Urmia accelerating the drying up of the lake, but it has also increased nitrate loads. Therefore, it can be recommended to take counter measures within the catchment area to improve the ecological status of Lake Urmia.

Evaluation of Streamflow under Climate Change in the Zambezi River Basin of Southern Africa

The Zambezi River basin is the fourth largest basin in Africa and the largest in southern Africa, comprising 5% of the total area of the continent. The basin is extremely vulnerable to climate change effects due to its highly variable climate. The purpose of this study was to evaluate the impact of climate change on streamflow in one of the sub-basins, the Kabombo basin. The multi- global climate model projections were used as input to the Soil Water Assessment Tool (SWAT) hydrological model for simulation of streamflow under RCP 4.5 and RCP 8.5 climate scenarios. The model predicted an annual streamflow increase of 85% and 6% for high uncertainty and strong consensus, respectively, under RCP 8.5. The model predicted a slightly reduced annual streamflow of less than 3% under RCP 4.5. The majority of simulations indicated that intra-annual and inter-annual streamflow variability will increase in the future for RCP 8.5 while it will reduce for the RCP 4.5 scenario. The predicted high and moderate rise in streamflow for RCP 8.5 suggests the need for adaptation plans and mitigation strategies. In contrast, the streamflow predicted for RCP 4.5 indicates that there may be a need to review the current management strategies of the water resources in the basin.

Recharge assessment in the context of expanding agricultural activity: Urucuia Aquifer System, western State of Bahia, Brazil

Groundwater recharge rate estimation is crucial to sustainable development of aquifers in intensely pumped regions, such as the Urucuia Aquifer System (UAS). A sedimentary aquifer in Western Bahia, Brazil, that underlies one of the major agricultural areas of the country where there has been major growth of irrigated areas. This study seeks to evaluate the recharge component of the water budget in the UAS area, based on three complementary techniques. The double-ring infiltrometer test was used to evaluate surface infiltration capacity, an important control on recharge. Water level data from wells (2011–2019 period, 19 wells) in the Brazilian Geological Survey's Integrated Groundwater Monitoring Network (RIMAS-CPRM) was used to estimate the aquifer recharge using the water table fluctuation (WTF) method. Additionally, this study used the Soil Water Assessment Tool (SWAT) model in two selected sub-basins to estimate deep recharge from the surface hydrological data. The results of the infiltrometer tests show a notable difference in the infiltration rates between the natural vegetation zones and cropped areas. The WTF and SWAT simulations results suggest similar ranges of recharge rate (an average of 24% of precipitation, in both methods). Results of the study indicate equivalence of these methods to estimate the recharge in sedimentary unconfined aquifers as UAS.

Assessment of Low-Impact development for managing aquatic ecosystem

Urban aquatic life communities are among the most endangered species in the United States, and their decline has been linked to pollutants and sediments from urban development. Low Impact Development (LID) practices were applied to manage urban stormwater runoff as part of green infrastructure. However, there remains a debate regarding the role played by LIDs in protecting aquatic life due to a lack of large-scale evidence. Given this knowledge gap, a Sub-hourly time step SWAT (Soil Water Assessment Tool) model was calibrated and validated to evaluate the potential impact of LID practices on aquatic life in the Blunn Creek Watershed in Austin-Texas.The evaluation of LID practices performance was based on (i) incorporating and representing these practices into the SWAT model, (ii) studying output flows, and (iii) assessing watershed hydrological responses and their impact on aquatic life communities. Several measures such as reduction in peak flows, increasing both baseflows, and Aquatic Life Potential (AQP) values were used to assess flows coming out of LID practices. The types of LIDs considered were raingarden, permeable pavement and detention pond.Results showed that a combination of permeable pavement and raingarden resulted in the greatest percentage of increase in AQP values and baseflows and the greatest reduction in peak flows. The detention pond had the least percentage increase in AQP and baseflows as well as the least percentage of reduction in peak flows. The findings of this study are likely to be of interest to policymakers. LIDs are efficient applications on a watershed scale and could contribute to reduce total runoff and enhance outflow water quality. This study provides an in-depth discussion over the latest essence of LID technologies, which magnify their capabilities to control stormwater, while also protecting urban aquatic life. Cities and developers should encourage the development of green cities using LID technologies.