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Munition constituents (MC) in stormwater runoff have the potential to move these pollutants into receiving bodies at military installations. Here we present further evaluation of a passive and sustainable biofilter technology for removal of dissolved MC from simulated surface runoff by combined sorption-biodegradation processes under dynamic flow conditions. Columns were packed with MC sorbents Sphagnum peat moss and cationized (CAT) pine shavings with and without wood-based biochar. Some columns also received biodegradable polymers as a slow-release carbon source and MC degrading bacterial cultures. MC removal was greater under combined sorption-biodegradation conditions than under sorption only conditions, ranging from 2.5-fold for 2,4,6-trinitrotoluene (TNT) to > 25-fold for hexahydro-1,3,5-trinitro-s-triazine (RDX). Biochar improved removal for some MC, which was attributed to it acting as a buffer by its ability to sorb/degrade these compounds, thus delaying their elution from the columns until the biodegradation activity increased. It was also found that labile carbon source availability, rather than microbial culture viability, was responsible for the apparent reduction in energetic removal over time. These results provide a foundation for further development of technologies for remediation of energetic compounds in military range stormwater runoff., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Relevance. Modern urbanization processes in Kharkiv are accompanied by an increase in anthropogenic pressure on the natural component, compaction of buildings and reduction of green areas. The concept of green infrastructure is used in many countries around the world; it is the best way to reorganize urban space into modern cities. The purpose of the article is a determination of quality changes of water runoff after passing through of green roofs in Kharkiv, Ukraine. Material and methods. A green roof is the roof of a build, partially or completely covered with vegetation and soil layer. Green roofs are divided into “intensive” and “extensive” types. In the research was studied the frequency of use of green roofs in construction and landscaping on the example of Kharkiv, was conducted an inventory of green roofs in Kharkiv. As the number of green roofs in Kharkiv is rather small, is optimal to choice the particular test sites for research. For chemical analysis, were taken samples of snow, surface runoff from the flat, and sloping green roofs and roof without greening for the content of pollutants. Chemical analysis of the samples was performed by the Laboratory of Analytical Ecological Research of V.N. Karazin Kharkiv National University. The laboratory has the attestation and certificate of ISO 10012:2005 № 01-0155/2019. The study determined the following indicators: pH, nitrites, nitrates, transparency, smell, turbidity, chlorides, general rigidity, total alkalinity, ammonia, zinc, copper, manganese, cadmium, total iron, chromium. Two types often represent green roofs in Kharkiv: parking roofs and cellars. Points of samples are located at Shevchenkivsky and Kholodnohirsky districts. Results and discussion. Results of a study of snow and runoff sampling after a green roof and a roof without landscaping show that most water quality indicators improve after water passes through green areas. Thus, at points the pH, general rigidity, alkalinity, concentration of chlorides, chromium are decrease. The green roof of the first point (parking) also reduces the concentration of nitrites, ammonia, zinc and manganese. The concentration of iron also decreases in the second point. However, there is an increase in the concentration of heavy metals in the water due to their accumulation in the substrate of the green roof. The results of the study are can be used by the Post-Soviet countries, as previously the impact of surface runoff was considered only in terms of the flow of pollutants from storm sewers to water bodies. Conclusion. The results of the study indicate that green roofs contribute to the treatment of runoff, natural replenishment of surface water bodies and groundwater and reduce the load on municipal wastewater treatment plant.

Water balancing techniques are strategies for resolving key theoretic and applied hydrologic challenges. The primary goals of the study are to examine the climatic characteristics and conditions that will be utilized in the water balancing approach used in the Rawandoz located in northeastern Iraq. The meteorological data from Soran meteorological station’s 2000 to 2020 were applied to analyze the climate patterns of the research region. The annual rainfall average is 750.50 mm, while the annual evaporation is 1497.80 mm. The average monthly humidity, temperature, and sunshine remained 73.8 percent, 18.50 °C, and 8 hours/day, respectively. The Kharrufa technique has been calculated the potential evapotranspiration (PET), water deficit and surplus and the Soil Conservation Service method (SCS) has been used to calculate surface runoff (Rs). The annual potential evapotranspiration, water surplus, and deficit are calculated to be 1900.27 mm, 430.10 mm, and 1579.90 mm, respectively, with an annual runoff of 376 mm. The standardized precipitation index (SPI) was produced to assess climatic drought over a variety of duration; the mean value is 0.562, indicating that the area is moist. The results of many climate classification reveal that the study area in humid to moist climate classification.

Study region: The Loess Plateau, China. Study focus: Land-use and rainfall characteristics are two crucial influencing factors that affect the surface runoff and soil loss process; however, less attention has been paid to nested watersheds in vulnerable geo-ecosystems. Here we analyzed rainfall characteristics impacts on runoff and sediment in one of the nested watersheds, which contains six sub-watersheds with different land uses. According to rainfall amount, duration, and maximum rainfall intensity within 30 min (I30), 180 rainfall events during 2004–2019 were categorized into four types using K-means clustering method, and different hydrological years were distinguished. New hydrological insights for the study region: The runoff coefficient and sediment yield under the rainfall regime Ⅰ (little precipitation, moderate duration of precipitation, low intensity of precipitation) were the lowest; under the rainfall regime Ⅳ (high precipitation, short duration of precipitation, high intensity of precipitation), these values were the largest. The average runoff coefficient among the six sub-watersheds analyzed varied as follows: farmland watershed > farming-pastoral watershed > closed watershed > secondary forest watershed > mixed forest watershed > plantation watershed. The closed watershed had the lowest average sediment yield, while the farming-pastoral watershed showed the highest one. In addition, the runoff coefficient and sediment yield also changed differently in various hydrological years. The results of this study suggest that natural restoration measures are the optimal choice for coordinating the relationship between surface runoff and sediment yield. Enhanced long-term monitoring is needed to accurately describe watershed processes.

Land degradation is a pivotal environmental concern, bearing substantial impacts in the Gidabo river basin (GRB) in Ethiopia, prompting a critical need for effective mitigation strategies. In this study, we aimed to assess the dynamics of land degradation pathways in the context of change in climate and land use. The identification of potential erosion hotspots and the appraisal of management strategies was also carried out. The Soil and Water Assessment Tool (SWAT) and the Good Practice Guidance (GPG) framework was employed. The results revealed a compelling synergy between land use dynamics and climate changes, asserting joint and individual prevalence in influencing surface runoff and sediment yield. The past simulation revealed 4–5.9% and 24–43% increments in mean annual runoff and sediment yield, respectively. While the near (2021–2040) and mid (2041–2060) future scenarios displayed varying trends under RCP4.5 and RCP8.5. Furthermore, sub-basins prone to soil erosion risk were identified, thereby enabling targeted conservation efforts. The assessment of trends in land degradation neutrality (LDN) unveiled the expansion of land degradation trajectories (by 26%) from 1985–2003 to 2003–2021. This might be attributed to the dynamic interplay between climate and land use land cover (LULC) change, with croplands and bare land emerging as high-risk degraded areas. Addressing these concerns, soil/stone bund, terracing, contour farming, and reforestation practice can significantly reduce the annual sediment yield in the future. The integration of soil erosion indicators with LDN sub-indicators can provide a more comprehensive approach that can lead to more effective land management and restoration strategies to achieve the LDN goal. The findings of this study could contribute crucial insights and substantial implications for policymakers, land managers, and conservationists. Moreover, future efforts should be directed to expand investigations into diverse land degradation pathways and mitigation measures.

Olive groves rank among the cropping systems facing higher erosion risk in Mediterranean Europe. The adoption of erosion control soil management practices is key for reducing such risk and driving olive production towards sustainability. This field experimental study aimed to quantify the erosion control performance of improved soil management as compared to conventional soil management in olive groves of NE Portugal. The design aimed to compare the effects of introducing no-tillage (NT) to a conventionally managed (T) olive grove and those with complementing ground cover by adventitious species (NS) with a sown cover (S) and comprised four treatments: TNS (reference for conventional), TS, NTNS and NTS. Erosion microplots (4 m2) were installed (two per treatment), recording soil loss, runoff and ground cover in seven erosion events throughout one year. The best erosion control performance was found in NTNS (low-cost improved soil management treatment) with 50% and 85% reductions in soil loss, respectively, in the annual total and in erosion events following large precipitation periods. Plots with adventitious vegetation ground cover performed better in soil loss control than the sown ones. Converting to no-tillage, as compared to sowing herbaceous vegetation to increase ground cover, proved more performant and less hazardous for improving erosion control in olive groves.

Copyright of Mustafa Kemal University Journal of Agricultural Sciences / Mustafa Kemal Üniversitesi Tarım Bilimleri Dergisi is the property of Mustafa Kemal University, Faculty of Agriculture 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.)

An adequate representation of the relationship between effective rainfall and rainfall losses is required in hydrological rainfall–runoff models to reduce the uncertainty of the modelling results. This study evaluates the performance of several hydrological rainfall loss methods using the experimental data obtained from a laboratory small-scale physical landslide model with variable slope inclination, homogenous material and no vegetation effects. Three different experiments were selected and five rainfall loss methods were tested to evaluate their performance in reproducing the experimental results from the perspective of the surface runoff formation on the experimental slope. Initial and calibrated parameters were used to test the performance of these hydrological rainfall loss methods. The results indicate that the initial parameters of the rainfall loss model can satisfactorily reproduce the experimental results in some cases. Despite the fact that the slope material characteristics used in the laboratory experiments were relatively homogenous, some well-known methods yielded inaccurate results. Hence, calibration of the rainfall loss model proved to be essential. It should also be noted that, in some cases, the calibrated model parameters were relatively different from the initial model parameters estimated from the literature. None of the tested hydrological rainfall loss methods proved to be superior to the others. Therefore, in the case of natural environments with heterogeneous soil characteristics, multiple rainfall loss methods should be tested and the most suitable method should be selected only after cross-validation or a similar evaluation of the tested methods. [ABSTRACT FROM AUTHOR]

Nowadays surface runoff pollution as a crisis of human societies, has forced most countries to seek legal solutions to solve this phenomenon, the most important of which is the establishment of civil liability in this area. Although, according to economic analysis, compensation can not have much effect on optimal deterrence, nevertheless, its effect on reducing water pollution can not be denied. This study, after a comprehensive review of available sources and then analyzing the findings, has concluded that the mere existence of pollution causes harm, so it is sufficient to determine the causality relationship between the pollution and its actor in order to establish civil liability; In addition, the government can be held liable for damages, both in terms of supervision and ownership, and by providing a broad interpretation of the concept of "beneficiary", it can be said that NGOs are considered "beneficiaries" in making such claims and assuming victory in litigation, compensation can be used for sustainable development. Finally, according to the model of sustainable development in the economy, the production of goods is not only a subordinate of labor and capital, but must also be considered in the production process, materials and environmental goods such as water. Therefore, from the perspective of environmental economics, water pollution is considered as a cost of production or consumption, and the higher this cost, the optimal production and economic growth will not be a subordinate of sustainable development. [ABSTRACT FROM AUTHOR]

Urban flooding is considered one of the hazardous disasters in metropolitan areas, especially for those located in arid regions. Due to the associated risks of climate change in increasing the frequency of extreme rainfall events, climate-induced migration to urban areas leads to the intensification of urban settlements in arid regions as well as an increase in urban expansion towards arid land outskirts. This not only stresses the available infrastructure but also produces substantial social instability due to unplanned urban growth. Therefore, this study sheds light on the main factors that are increasing the flood risk, through examining the consequences of rapid urban growth and the performance of drainage networks on urban flood volumes and comparing it with the effects induced by climate change on the surface runoff. The effect of urbanization is assessed through land use maps showing the historical urbanization conditions for the past 30 years, while considering the role of urban planning and its effect on exacerbating surface runoff. Six climate projection scenarios adopted from three Global Climate Models under two Representative Concentration Pathways (4.5 and 8.5) during the period (2006–2020) were compared to ground observed rainfall data to identify which climate scenario we are likely following and then evaluate its effects on the current rainfall trends up to the year 2050. The significance of the drainage design in the mitigation or increase of surface runoff is evaluated through capacity-load balance during regular and extreme storms. It is found that using impervious surfaces coupled with poor planning causing the blockage of natural flood plains led to an increase in the total runoff of about 180%, which is three times more than the effect induced by climate change for the same analysis period. Climate change decreased the intensities of 2- and 5-year rainfall events by 6% while increasing the intensities of extreme events corresponds to 100-year by 17%. Finally, the urban drainage had a distinguished role in increasing surface runoff, as 70% of the network performed poorly during the smallest rainfall event of 2-year return period. The study emphasizes the urgency to re-evaluate the existing and future urban drainage design approach: although urban development and climate change have inevitable effects on the increase in urban flood volumes, it could be alleviated through improved infrastructures. [ABSTRACT FROM AUTHOR]

Phosphorus (P) in surface runoff from purple soil is a critical element of agricultural non-point source pollution, leading to eutrophication of surface waters in the Three Gorges Reservoir Area (TGRA) of China. This work aimed to understand the processes and mechanisms of P losses from bare purple soil. Based on an indoor rainfall simulation experiment, we focused on the processes of surface runoff and P losses via different hydrological pathways. Experimental treatments included three simulated rainfall intensities, four slope gradients, and three fertilizer treatments. P loss from sediment was the main pathway in the purple soil, and bioavailable P was mainly transferred in dissolved P (DP) of runoff water. The P loss loads tend to grow with the increase of the slope until 25° for the maximum load of runoff water and 20° for the maximum load of sediment. Concentrations of DP in the surface runoff after fertilizer application can exceed the estimates of those required for accelerated eutrophication. Sediment P control might be an essential way for reducing P loss in purple soil for the local government and farmers of TGRA. [ABSTRACT FROM AUTHOR]

Changes related to urban infrastructure directly affect the ecological environment, including soil properties. The purpose of this study is to investigate the anti-erosion and flow-regulating effect of park stands in complex terrain conditions of Kyiv. Forestry and tax indicators of plantings are established according to recognized tax methods. The upper layers of the soil were studied by determining the hardness, water permeability, density, and humidity on paths and in stands. Soil hardness in plantations increases from 9.1 ± 0.76-10.8 ± 1.01 kg/cm² to 15.4 ± 0.25-30.8 ± 0.15 kg/cm², which is associated with the intensity of trampling them. Therewith, the soil changes from loose to medium loose and even dense. Determination of water permeability also showed a significant discrepancy, from 18.6 ± 0.76-20.6 ± 0.66 mm/min to 1.9 ± 0.10-5.7 ± 0.33 mm/min, respectively. Research has confirmed the inverse correlation between soil hardness and water permeability. The obtained indicators of soil density in the stands (1.12-1.20 g/cm³) and on the paths (1.34-1.66 g/cm³), albeit without sharp differences, in both cases indicate their criticality for further normal development of stands. Changes in soil moisture data in stands (16.9-20.6%) are decreasing in comparison with paths (11.2-12.6%), which also indicates the deterioration of growing conditions. The presence of active roots in the upper thickness of the soil on the control was 5.8-9.8 g, and on the paths, depending on the intensity of trampling, from 0.0 to 2.2 g. The territories under study were surveyed to identify characteristic erosion processes. It was established that the park spaces are in a satisfactory condition and fully perform an anti-erosion effect. The threat of erosion processes occurs on paths of intense load. The results obtained can be used for monitoring and regulating anthropogenic load. [ABSTRACT FROM AUTHOR]

Peatland restoration aims to achieve pristine water pathway conditions to recover dispersed wetness, water quality, biodiversity and carbon sequestration. Restoration monitoring needs new methods for understanding the spatial effects of restoration in peatlands. We introduce an approach using high-resolution data produced with an unmanned aircraft system (UAS) and supported by the available light detection and ranging (LiDAR) data to reveal the hydrological impacts of elevation changes in peatlands due to restoration. The impacts were assessed by analyzing flow accumulation and the SAGA Wetness Index (SWI). UAS campaigns were implemented at two boreal minerotrophic peatland sites in degraded and restored states. Simultaneously, the control campaigns mapped pristine sites to reveal the method sensitivity of external factors. The results revealed that the data accuracy is sufficient for describing the primary elevation changes caused by excavation. The cell-wise root mean square error in elevation was on average 48 mm when two pristine UAS campaigns were compared with each other, and 98 mm when each UAS campaign was compared with the LiDAR data. Furthermore, spatial patterns of more subtle peat swelling and subsidence were found. The restorations were assessed as successful, as dispersing the flows increased the mean wetness by 2.9–6.9%, while the absolute changes at the pristine sites were 0.4–2.4%. The wetness also became more evenly distributed as the standard deviation decreased by 13–15% (a 3.1–3.6% change for pristine). The total length of the main flow routes increased by 25–37% (a 3.1–8.1% change for pristine), representing the increased dispersion and convolution of flow. The validity of the method was supported by the field-determined soil water content (SWC), which showed a statistically significant correlation (R2 = 0.26–0.42) for the restoration sites but not for the control sites, possibly due to their upslope catchment areas being too small. Despite the uncertainties related to the heterogenic soil properties and complex groundwater interactions, we conclude the method to have potential for estimating changed flow paths and wetness following peatland restoration. [ABSTRACT FROM AUTHOR]

Losses of nitrogen and phosphorus from farmland are the main sources of eutrophication pollutants. In order to calculate the quantities of nitrogen and phosphorus losses via surface runoff during a rice production cycle and investigate the rules, a paddy field in-situ monitoring site was established in the main rice production area of Changzhou, China. The import and loss of water, nitrogen and phosphorus in the paddy field had been monitored. The results showed that the imports of nitrogen and phosphorus via rainfall and irrigation were 2.663 8 g/m² and 0.154 3 g/m² respectively in the paddy field during the experimental period. The losses of nitrogen and phosphorus via runoff water, drainage water and runoff sediment were 4.732 5 g/m2 and 0.342 5 g/m² respectively. So the net exports of nitrogen and phosphorus from the paddy field(deduction of nitrogen and phosphorus imports from the losses)were 2.068 7 g/m² and 0.188 2 g/m² respectively. With regard to the ways of nitrogen and phosphorus losses, the quantities of nitrogen and phosphorus losses via drainage water accounted for more than 80% and 70% of total nitrogen and phosphorus losses respectively. On the time of nitrogen and phosphorus losses, the quantities of nitrogen and phosphorus losses in July accounted for about 60% of total nitrogen and phosphorus losses. The losses of nitrogen and phosphorus in June accounted for more than 20% of total nitrogen and phosphorus losses. The results indicate that reducing drainage water of paddy field is the most effective measure to cut down the losses of nitrogen and phosphorus from paddy field, especially in July. [ABSTRACT FROM AUTHOR]

Forest to oil palm plantations conversion has changed soil's physical properties significantly. It caused significant changes in the hydrological cycle and affects the water resources around the research site. One of the strategies that could minimize the negative impact of monoculture oil palm plantations is better plantation management by implementing a mixed cropping system (agroforestry). This study aims to analyze the infiltration, surface runoff, and surface runoff coefficient in agroforestry and monoculture oil palm. This observation was conducted in the oil palm plantation area of PT Humusindo Makmur Sejati, Bungku Village, Bajubang District, Batanghari Regency. The infiltration rate was calculated according to the Horton method, and the amount of runoff in agroforestry and oil palm monoculture used the soil conservation service-curve number method. The results showed differences in infiltration, surface runoff, and runoff coefficients between the agroforestry land and the monoculture oil palm. The highest infiltration is in A48, which is 42,00 cm/hour in the dry season and 18,00 cm/hour in the rainy season. The lowest runoff is in A23, which is 70.14 mm with a runoff coefficient of 0.04. The highest runoff occurred in S48 of 339.88 mm, with a runoff coefficient of 0.19. The differences in infiltration, surface runoff, and runoff coefficient in this study are affected by the vegetation density and the amount of litter. [ABSTRACT FROM AUTHOR]

Rice production involves abundant water and fertilizer inputs and is prone to nitrogen (N) loss via surface runoff and leaching, resulting in agricultural diffuse pollution. Based on a two-season paddy field experiment in Jiangsu Province, China, field water and N dynamics and their balances were determined with the well-calibrated HYDRUS-1D model. Then, scenarios of different controlled drainage and N fertilizer applications were simulated using the HYDRUS-1D model to analyze the features and factors of N loss from paddy fields. Evapotranspiration and deep percolation were the two dominant losses of total water input over the two seasons, with an average loss of 50.9% and 38.8%, respectively. Additionally, gaseous loss of N from the whole soil column accounted for more than half of total N input on average, i.e., ammonia volatilization (17.5% on average for two seasons) and denitrification (39.7%), while the N uptake by rice accounted for 37.1% on average. The ratio of N loss via surface runoff to total N input exceeded 20% when the N fertilizer rate reached 300 kg ha−1. More and longer rainwater storage in rice fields under controlled drainage reduced surface runoff losses but increased the risk of groundwater contamination by N leaching. Therefore, compared with raising the maximum ponding rainwater depth for controlled drainage, optimizing N fertilizer inputs may be more beneficial for controlling agricultural diffuse pollution by reducing N loss via surface runoff and leaching. The HYDRUS-1D model provides an approach for the quantitative decision-making process of sustainable agricultural water and N management. [ABSTRACT FROM AUTHOR]

The topographic threshold is based on the power relationship between area and slope and is widely applied in gully-erosion research; however, this relationship requires further testing. Accordingly, the Alamarvdasht Lamerd and Fadagh Larestan regions in Fars Province, Iran, were selected as case studies to explore the topographic threshold for gullies. Thirty active gullies were identified in each study area during field surveys, and data describing land use and land cover, drainage areas, slope, and the physical and chemical properties of the soils were assembled. Multivariate analysis was conducted using SPSS to determine the effects of these factors. Using the power relationship between the catchment area and slope for each gully, the analyses explored critical controls for gully development. The results showed that surface runoff was the most significant effective factor for gullies in the study areas. Sparse ground cover, fine-textured soils, and inappropriate land use contribute to gully development. The results suggest that the relationship between slope and drainage area in the Fadagh Larestan case study is S = 0.0192 A−0.159 for gully headcut areas and S = 0.0181 A−0.258 at gully outlets. The corresponding values of the exponent β at the gully headcuts and outlets at Fadagh were − 0.15, and −0.25, respectively. The corresponding relationships for gullies in the Alamarvdasht Lamerd area for the gully headcuts and outlets were S = 0.0143 A− 0.061 and S = 0.0073 A−0. 18, respectively, with β values of − 0.06 and − 0.18. This study provides a basis for determining the thresholds for initiating gully development. Analyses of the effective factors provide clues to improve the management of bare lands to prevent the initiation of gully erosion. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board 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.)

Assessing the spatiotemporal dynamics of land use land cover (LULC) change on water resources is vital for watershed sustainability and developing proper management strategies. Evaluating LULC scenarios synergistically with hydrologic modeling affords substantial evidence of factors that govern hydrologic processes. Hence, this study assessed the spatiotemporal effects and implications of LULC dynamics on groundwater recharge and surface runoff in Gilgel Gibe, an East African watershed, using the Soil and Water Assessment Tool (SWAT) model. Three different LULC maps (2000, 2010, and 2020) were derived from Landsat images, and the comparisons pointed out that the land-use pattern had changed significantly. The agricultural land and grassland cover increased by 3.76% and 1.36%, respectively, from 2000 to 2020. The implications acquired for 2000 show that forested land covers decreased by 5.49% in 2020. The SWAT simulation process was executed using a digital elevation model, soil, LULC, and weather data. The model was calibrated and validated using streamflow data to understand the surface runoff and groundwater recharge responses of each Hydrologic Response Units on reference simulation periods using the Calibration and Uncertainty Program (SWAT-CUP), Sequential Uncertainty Fitting (SUFI-2) algorithm. The observed and simulated streamflows were checked for performance indices of coefficient of determination (R2), Nash–Sutcliffe model efficiency (NSE), and percent bias (PBIAS) on monthly time steps. The results show that there is good agreement for all LULC simulations, both calibration and validation periods (R2 & NSE ≥ 0.84, −15 < PBIAS < +15). This reveals that for the LULC assessment of any hydrological modeling, the simulation of each reference period should be calibrated to have reasonable outputs. The study indicated that surface runoff has increased while groundwater decreased over the last two decades. The temporal variation revealed that the highest recharge and runoff occurred during the wet seasons. Thus, the study can support maximizing water management strategies and reducing adverse driving environmental forces. [ABSTRACT FROM AUTHOR]

The revised Morgan, Morgan and Finney (rMMF) water erosion model calculates annual surface runoff and soil loss from field-sized areas. The original version of the rMMF is neither suited to calculate water erosion along irregular hillslopes, nor capable to allow infiltration of once generated surface runoff at places where the runoff speed slows down, and infiltration could occur under natural conditions. The aim of this article is to describe a new hillslope version of the rMMF model that allows infiltration of surface runoff, and to show examples of soil erosion modelling along real and hypothetical hillslopes. The new hillslope version (hMMF) splits the entire hillslope into a number of sections that have individual properties, such as slope angle, slope length, soil properties and vegetation characteristics. The surface runoff along the slope is calculated by summing the volume of surface runoff generated in a particular section with the surface runoff coming from the immediate upslope section. The related sediment transport is calculated for each section using the calculated detachment for the section, the sediment coming from the upslope section and the transport capacity. A new variable is introduced to account for infiltration of surface runoff and allows simulating the effects of soil and water conservation structures on water erosion. The model was tested using measured data from plots in Africa, Asia, the US and Europe, as well as for a surveyed hillslope in Tunisia (Barbara watershed). Overall, the performance of the hMMF was reasonable for surface runoff and poor for soil loss when recommended input variable values are used. Calibration of the model resulted in a good performance, which shows the capability of the hMMF model to reproduce measured surface runoff and erosion amounts. In addition, realistic water erosion patterns on hillslopes with soil and water conservation can be simulated.

Climate change impacts on the water cycle can severely affect regions that rely on groundwater to meet their water demands in the mid- to long-term. In the Lake Tana basin, Ethiopia, discharge regimes are dominated by groundwater. We assess the impacts of climate change on the groundwater contribution to streamflow (GWQ) and other major water balance components in two tributary catchments of Lake Tana. Based on an ensemble of 35 bias-corrected regional climate models and a hydrologic catchment model, likely changes under two representative concentration pathways (RCP4.5 and 8.5) are assessed. No or only slight changes in rainfall depth are expected, but the number of rainy days is expected to decrease. Compared to the baseline average, GWQ is projected to decrease whereas surface runoff is projected to increase. Hence, rainfall trends alone are not revealing future water availability and may even be misleading, if regions rely heavily on groundwater. HIGHLIGHTS Change in the rainfall intensity affects the availability of groundwater in a catchment.; Rainfall projections from different global and regional climate models show disparities among each other.; The projected actual evapotranspiration is expected to decrease in the future for the study region due to less water availability.;

This study investigated the agronomic response and economic return of wheat grown in compacted and non-compacted soils to represent the conditions of non-controlled (non-CTF) and controlled traffic (CTF) systems, respectively. Yield-to-nitrogen responses were derived after application of urea, DMPP-treated urea, and UAN at rates between 0 and 300 kg ha−1 N. Soil properties were measured to guide parametrisation of APSIM, which was used to assess long-term (50 years) effects of CTF and non-CTF soil conditions on crop productivity, rainfall-use efficiency (RUE) and surface runoff. Grain yield and yield components were significantly higher in CTF compared with non-CTF. When N inputs were optimised, N use efficiency (NUE) was more than double in CTF (≈23%) compared with non-CTF (≈9%). RUE was about 15% higher in CTF, which concurrently reduced the amount of surface runoff compared with non-CTF. For years with average rainfall (240-mm in-crop), yield penalties of up 12% may be expected in non-CTF. APSIM simulations showed that increased productivity, and inter-annual yield stability, can increase gross margin of wheat by AUD30-50 ha−1 depending on in-crop rainfall and the tillage method used. In non-CTF systems, improvements in NUE and RUE are constrained by soil compaction. Enhanced efficiency fertilizers cannot compensate for other stresses caused by compaction and therefore cannot achieve the same NUE and RUE as the CTF system. Adoption of CTF in water-constrained environments improves profitability and resource-use efficiency.

Article highlights The major land use and cover changes undertaken in the endorheic Hayk Lake basin between 1989 and 2015 were detected and linked to changes in rainfall-runoff relationship using the HEC-HMS hydrological model. The simulation result indicated that the change in land use and cover raised surface runoff individually, but its combination with climate change had a negative impact on Hayk Lake's water level. Presented the scientific understanding of the integration of remote sensing, GIS, and the hydrological model at the local level can help to address the persistent threat of water level reduction in Hayk Lake.

Hexavalent chromium (Cr(VI)) poses severe health and environmental risk, especially in industrial vicinities where runoff concentrations are elevated by evaporation and sedimentation dynamics. This study investigates the utilization of modified graphene oxide (GO) with abundant active groups as an adsorbent. The novel adsorbent, GO/ATA, was synthesized by covalently attaching a Schiff base (ATA) to GO via a coupling reaction, enhancing its adsorptive properties. The physicochemical properties of GO/ATA were meticulously characterized to ascertain structural and morphological attributes. GO/ATA exhibit exceptional adsorptive capabilities, surpassing the performance parameters of other adsorbents with a maximum of 243.3 mg g−1 at 298 K. The electrostatic attraction between the N-containing functional groups in the graphene oxide and Schiff base composite (GO/ATA) and Cr(VI) is the main mechanism behind the adsorption process; Subsequently, a reduction reaction occurs, facilitated by the thiol and N-containing functional groups in GO/ATA composite, resulting in the transformation of Cr(VI) into Cr(III). This transformation is essential for the following chelation process occurring on the surface of the adsorbent material. Evaluations of recyclability indicated that GO/ATA retains substantial adsorption efficacy, with a reduction from 91.2% to 72.7% over five cycles, thus affirming its recyclability and practical application in the remediation of Cr(VI)-contaminated waterborne environment. Additionally, GO/ATA's effectiveness in removing Cr(VI) from surface runoff was specifically tested, emphasizing its economic and environmental viability. [Display omitted] • A two-step method was used to synthesize GO/ATA adsorbent material. • GO/ATA had rough surface, highly interconnected and porous structure. • GO/ATA's maximum adsorption capacity for Cr(VI) was 243.3 mg g−1, 3.6 times of GO. • Adsorption mechanism: adsorption and reduction of Cr(VI). • GO/ATA's superb practical performance: 94.9% Cr(VI) removal rate in surface runoff. [ABSTRACT FROM AUTHOR]

The transport of oxytetracycline, chlortetracycline, and ivermectin from manure was assessed via surface runoff on irrigated pasture. Surface runoff plots in the Sierra Foothills of Northern California were used to evaluate the effects of irrigation water application rates, pharmaceutical application conditions, vegetative cover, and vegetative filter strip length on the pharmaceutical discharge in surface runoff. Experiments were designed to permit the maximum potential transport of pharmaceuticals to surface runoff water, which included pre-irrigation to saturate soil, trimming grass where manure was applied, and laying a continuous manure strip perpendicular to the flow of water. However, due to high sorption of the pharmaceuticals to manure and soil, less than 0.1% of applied pharmaceuticals were detected in runoff water. Results demonstrated an increase of pharmaceutical transport in surface runoff with increased pharmaceutical concentration in manure, the concentration of pharmaceuticals in runoff water remained constant with increased irrigation flow rate, and no appreciable decrease in pharmaceutical runoff was produced with the vegetative filter strip length increased from 30.5 to 91.5 cm. Most of the applied pharmaceuticals were retained in the manure or within the upper 5 cm of soil directly beneath the manure application sites. As this study evaluated conditions for high transport potential, the data suggest that the risk for significant chlortetracycline, oxytetracycline, and ivermectin transport to surface water from cattle manure on irrigated pasture is low.

Pathogen transport through the environment is complicated, involving a variety of physical, chemical, and biological processes. This study considered the transfer of microorganisms from soil into overland flow under rain-splash conditions. Although microorganisms are colloidal particles, they are commonly quantified as colony-forming units (CFUs) per volume rather than as a mass or number of particles per volume, which poses a modeling challenge. However, for very small particles that essentially remain suspended after being ejected into ponded water and for which diffusion can be neglected, the Gao model, originally derived for solute transfer from soil, describes particle transfer into suspension and is identical to the Hairsine–Rose particle erosion model for this special application. Small-scale rainfall experiments were conducted in which an Escherichia coli (E. coli) suspension was mixed with a simple soil (9:1 sand-to-clay mass ratio). The model fit the experimental E. coli data. Although re-conceptualizing the Gao solute model as a particle suspension model was convenient for accommodating the unfortunate units of CFU ml−1, the Hairsine–Rose model is insensitive to assumptions about E. coli per CFU as long as the assumed initial mass concentration of E. coli is very small compared to that of the soil particle classes. Although they undoubtedly actively interact with their environment, this study shows that transport of microorganisms from soil into overland storm flows can be reasonably modeled using the same principles that have been applied to small mineral particles in previous studies.

Soil erosion is recognized as a threat to humankind and to natural ecosystems when sustainable limits are exceeded. Several researchers have used various tools, such as rainfall simulators, to assess extreme rainfall events and non-sustainable soil management practices. However, combinations of two different devices of different sizes has not been tested before, especially in vineyards. The aim is to verify whether plot size, connectivity processes and rainfall distribution affect the activation of soil erosion. In this research on soils cultivated with vineyards in the Moravia Region in the south-eastern part of the Czech Republic, we have performed various rainfall simulation experiments with a small device (1 × 1 m) and with a large device (8 × 1 m). Our results show that the surface runoff was approximately 30% higher on the small plot than on the large plot. The large rainfall simulator produced sediment concentration that was up to 3 times higher, and soil loss that was up to 1.5 times higher, even when the surface runoff was 30%–50% lower for the large rainfall simulator. We therefore conclude that there is a clear influence of surface length and plot size on surface runoff, soil loss and sediment concentration activation. When planning their experiments, researchers need to consider that the type of device can have a drastic influence on the final results. Two devices subjected to the same rainfall intensity (60 mm h−1) can produce very different results, e.g., depending on plot size and kinetic energy. Our results can be effectively used to plan soil protection measures and to inform local authorities about areas prone to flooding and about loss of sediments.

Graphical Abstract

The Northeast Greenland Ice Stream (NEGIS), the largest basin in Greenland, is undergoing rapid and sustained dynamic change. However, the ice-flow behaviours over decadal timescales and the impacts of ice geometry and hydrology remain poorly understood. Here, we investigated the spatial and temporal characteristics of ice motions of three branches in NEGIS between 1985 and 2018 in response to bed topographic features and surface meltwater runoff based on 33 years of annual ice velocities derived from the satellite image of Landsat series. Spatial heterogeneities in ice velocity were found in three glaciers and were correlated with subglacial topography. Specifically, the peak velocities of both Nioghalvfjerdsfjorden and Zachariæ Isstrøm glaciers occur near the grounding line zone, where tidewater acts as a crucial force causing ice retreat, subglacial melting, and further acceleration. While for the Storstrømmen glacier, changes in the slope of the ice bed might cause an increase in ice motion in its inland segment. The temporal variability of ice velocity for both Nioghalvfjerdsfjorden and Zachariæ Isstrøm glaciers shows a clear regional speedup, with a mean increase of 14.60% and 9.40% in 2001–2018 compared to 1985–2000, but a widespread slowing of Storstrømmen glacier with a mean of 16.30%, which were related to a 184% surface runoff increase. This hydrodynamic coupling on ice motion over decadal timescales in these three glaciers is in line with previous studies on short-term acceleration in NEGIS induced by surface melt, not in agreement with negative feedback between enhanced surface meltwater production and ice motion previously reported in the southwest Greenland ice stream. Our work highlights crucial roles of subglacial topography and surface runoff on ice motion, which helps to promote understanding of dynamic changes of NEGIS response to changing atmospheric circumstances.

Hydrological simulation of the karst area is significant for assessing water resources accurately and exploring the relationship in the hydrologic cycle. However, the existence of sinkholes causes the spatial heterogeneity of aquifers and changes the distribution of surface water as well as groundwater, which makes the traditional hydrogeological model difficult to quantitatively characterize the hydrological processes of the sinkhole. Hence, improving the hydrological model for the karst area is a necessary direction at present. The soil and water assessment tool (SWAT) is one of the most widely used semi-distributed hydrological models right now in the world. In this study, we focused on the upper course of the South Panjiang River and used the pond module of the SWAT model to simulate karst sinkholes, modifying the source code to realize the rapid response to the recharge in karst sinkholes. After the improvement, the surface runoff, especially the peak value of the Xiqiao Hydrological Station at the outlet, has been reduced, while the baseflow of modified subbasins has been increased and the water yield is under a state of water balance. In addition, the model evaluation factor R2 was strengthened from 0.76 to 0.83 and NSE was strengthened from 0.66 to 0.79 of the Xiqiao Hydrological Station during the validation period. The improved model was used to analyze the spatial distribution of hydrological components. Also, it was found there are spatial relations between runoff modulus–slope and baseflow–surface runoff–land use types. The analysis demonstrated that the improved SWAT model could effectively change the hydrological components and simulate the rapid replenishment of karst sinkholes.

Heavy metal contamination in soil has become a serious environmental problem in China, and chromium is one of the major threats to human health. In order to better understand the transfer pattern of heavy metal hexavalent chromium from polluted sites into surface water, the influencing factors that affect solute transfer from soil into the surface runoff with linear and nonlinear adsorption equations based on a two-layer incomplete mixing model were analyzed in this study. The Quasi-Newton method was used to optimize model parameters by fitting with the experimental laboratory data of chromium (Cr(VI)) in surface runoff. The local sensitivity analysis and the Morris global sensitivity analysis approaches were used to assess the parameter importance of rainfall intensity p, the thickness of the mixing layer hmix, incomplete mixing parameter α and γ, the soil adsorption parameters, and the initial soil water content θ0. The study results showed that the optimized nonlinear models were better consistent with the experimental results than the linear adsorption equation model. The results of global sensitivity indicated that rainfall intensity p was the main factor influencing Cr(VI) transport from the soil into surface runoff. The hmix and the α in the two-layer model were vital parameters that influenced such transport processes. Moreover, the soil adsorption properties and the θ0 had the lowest effects on runoff Cr(VI) loss. The results indicate that for controlling pollution migration in surface runoff, it is essential to focus on the analysis of precipitation conditions and soil properties that control the thickness of the mixing layer and the degree of mixing.

The aim of the article was to verify the curve number (CN) values given in the National Engineering Handbook (NEH) methodology, whether they really correspond to all wide-row crops. The tested crops were maize, hops and potatoes grown using conventional and soil conservation technologies. All these crops are classified as wide-row crops, but they are very different in terms of the cultivation process. The basis for the calculation of our CN values were field measurements carried out using a rainfall simulator within the time span from 2014 to 2020 on the soil corresponding to hydrological group B in two repetitions: naturally dry soil corresponding to an ARC II curve and saturated soil corresponding to an ARC III curve. The results show that our calculated CN values for the conventional cultivation of wide-row crops are, in principle, the same as the CN values given in the NEH methodology. On the contrary, a certain difference was recorded in the soil conservation technologies with plant residues on the surface, in the case of naturally dry soil. Lower CN values are clearly seen in the technologies of no-till maize, strip-till maize and hops with catch crops, which was confirmed by the statistical tests, probably due to the interception and surface roughness.

The purpose of this study was to investigate the relationship between stream water quality and the surface runoff rate defined as the ratio of annual surface runoff to annual average precipitation. The surface runoff rate was first estimated in the Han River basin located in South Korea using the calibrated and validated HSPF model. Then a linear regression analysis was performed to investigate the correlation between the computed surface runoff rate and the observed water quality. It was found that there were statistically significant relationships between the surface runoff rate and concentrations of BOD, COD, and T-P and higher surface runoff rate led to the deterioration of water quality in streams. Finally, the applicability of the surface runoff rate as an indicator to measure the impact of land development on stream water quality was evaluated using a receiver operating characteristic (ROC) curve analysis. The ROC curve analysis indicated that the surface runoff rate could be utilized as a useful indicator to illustrate the degradation of stream water quality at the watershed scale. The results from this study also suggest that the surface runoff rate needs to be managed and controlled within about 15% to prevent the degradation of stream water quality. HIGHLIGHTS The HSPF model was applied for simulating hydrological components.; The linear regression analysis and receiver operating characteristic (ROC) curve analysis were utilized to analyze the impact of surface runoff rate on water quality.; There were significant relationships between the surface runoff rate and water quality.; Controlling the surface runoff rate within 15% is suggested to prevent the degradation of water quality.;

Climate change impact on the hydrology of the Betwa river basin, located in the semi-arid region of Central India, was assessed using the Soil and Water Assessment Tool (SWAT), driven by hypothetical scenarios and Model of Interdisciplinary Research on Climate version 5 (MIROC5) Global Circulation Model projections. SWAT-Calibration and Uncertainty Programs (SWAT-CUP) was used for calibration and validation of SWAT using multi-site streamflow data. The coefficient of determination, Nash–Sutcliffe efficiency, RMSE-observations standard deviation ratio and percent bias during calibration and validation period varied from 0.83–0.92, 0.6–0.91, 0.3–0.63 and −19.8–19.3, respectively. MIROC5 projections revealed an increase in annual mean temperature in the range of 0.7–0.9 °C, 1.2–2.0 °C and 1.1–3.1 °C during the 2020s, 2050s, and 2080s, respectively. Rainfall is likely to increase in the range of 0.4–9.1% and 5.7–15.3% during the 2050s and 2080s, respectively. Simulation results indicated 3.8–29% and 12–48% increase in mean annual surface runoff during the 2050s and 2080s, respectively. Similarly, an increase of 0.2–3.0%, 2.6–4.2% and 3.5–6.2% in mean annual evapotranspiration is likely during the 2020s, 2050s and 2080s, respectively. These results could be used for developing suitable climate change adaptation plans for the river basin. HIGHLIGHTS SWAT was calibrated at multi-site gauging stations in a semi-arid river basin.; Hypothetical climate change scenarios of Rainfall, Temperature and CO2 was used to assess the basin response.; Surface runoff was sensitive to rainfall change and ET was sensitive to CO2 change.; Surface runoff and ET are projected to increase during the 2050s and 2080s under RCP scenarios.; Climate change adaptation measures were suggested.;

Maize grown on sloped areas is susceptible to surface runoff and soil erosion, especially if traditional technology with tillage is employed. As a result, other solutions are being sought that address this risk and are acceptable to farmers. The combination of inter-row cultivation with the formation of small reservoirs appears to be a suitable alternative solution applicable in traditional corn cultivation. In the years 2020, 2021, and 2022, three plots of land in southern Bohemia, Czech Republic, were selected for testing, on which this approach was tested. During the field experiments, three variants were compared each year: inter-row cultivation with reservoirs, inter-row cultivation only, and a control without any mechanical intervention. All variants were subjected to rain simulation, from which the surface runoff was evaluated. The highest retention of runoff was manifested with reservoir cultivation by 2.4–4.2 min, compared to the cultivated variant, and 2–4.2 min compared to the control. This result would correspond to a difference of 5.7–9.8 mm retained precipitation and 4.6 to 7.3 mm, respectively. The hydraulic conductivity of the soil was evaluated after canopy closure. The lowest values were invariably reached in the reservoirs, up to 88% lower than with the cultivated variant and 79% lower than the control. The fresh matter yield of forage maize was shown to be inconclusively higher by up to 10% in 2020 and 2022 in cultivation with reservoirs. However, the dry matter yield was always lower in the variant with reservoirs compared to inter-row cultivation only. Overall, reservoir cultivation appears to be an effective method for the retention of rainwater on agricultural land with a slope up to 6° without a significant effect on the yield of maize.

Managing diffuse pollution from agricultural land requires a spatially explicit risk assessment that can be applied over large areas. Major components of such assessments are the precise definition of both channel networks that often originate as small channels and streams, and Hydrologically Sensitive Areas (HSAs) of storm runoff that occur on land surfaces. Challenges relate to regions of complex topography and land use patterns, particularly those which have been heavily modified by arterial drainage. In this study, a national scale, transferrable workflow and analysis were developed using a specifically commissioned LiDAR survey. Research on the first half of Northern Ireland (6927 km2) is reported where field-edge drain to major river channels were mapped from 1 m (16 points per metre) digital terrain models, and in-field HSAs were defined across over 400,000 fields with a median field size of 0.86 ha. Manual drainage mapping supplemented with a novel automated drainage channel correction process resulted in an unparalleled high-resolution national drainage network with 37,320 km of channels, increasing mapped channel density from 0.9 km km−2 to 5.5 km km−2. The HSAs were based on a Soil Topographic Index (STI) system using hillslope and contributing area models combined with soil hydraulic characteristics. In all, 249 km2 of runoff risk HSAs were identified by extracting the top 95th percentile of the modelled STI as the areas with the highest propensity to generate in-field runoff. At field and individual farm scale these targeted risk maps of diffuse pollution were delivered to over 13,000 farmers and form part of the nationwide Soil Nutrient Health Scheme programme. [Display omitted] • Channel network and runoff risk defined across 6927 km2 using a 1 m LiDAR DTM. • Hydrological correction resulted in mapping of 37,320 km channel network. • 249 km2 of Hydrologically Sensitive Area identified using a Soil Topographic Index. • Automated channel extraction process developed to reduce manual mapping by 40%. • Decision support maps produced and delivered to farmers across 409,946 fields. [ABSTRACT FROM AUTHOR]

The interplay of surface and shallow subsurface fluxes plays a critical role in controlling water movement in hillslope agroecosystems and impacting soil and plant health during prolonged dry periods, demonstrating a need for in-field monitoring. This study was conducted for two years (2021–2022) by combining field monitoring of the grass-covered inter-row area (passive wick lysimeter, surface runoff, and meteorological data), laboratory determination of soil hydraulic properties (SHPs), and numerical modeling with the aim to explore near-surface fluxes at the SUPREHILL Critical Zone Observatory (CZO) located on a hillslope vineyard. Additionally, sensitivity analysis for basic root water uptake (RWU) parameters was conducted. The model was evaluated (R2, RMSE, and NSE) with lysimeter (hillslope) and runoff (footslope) data, producing good agreement, but only after the inverse optimization of laboratory estimated hydraulic conductivity was conducted, demonstrating that adequate parameterization is required to capture the hydropedological response of erosion-affected soil systems. Results exhibit the dependence of runoff generation on hydraulic conductivity, rainfall, and soil moisture conditions. The data suggest different soil-rewetting scenarios based on temporal rainfall variability. Sensitivity analysis demonstrated that Leaf Area Index (LAI) was the most responsive parameter determining the RWU. The study offers an approach for the investigation of fluxes in the topsoil for similar sites and/or crops (and covers), presenting the methodology of self-constructed soil–water collection instruments.

The ubiquitous nature and environmental impacts of microplastic particles and fibers demand effective solutions to remove such micropollutants from sizable point sources, including wastewater treatment plants and road runoff facilities. While advanced methods, e.g., microfiltration and ultrafiltration, have shown high removal efficiencies of small-sized microplastics (<150 μm), the low flux encountered in these systems implies high operation costs and makes them less effective in high-capacity wastewater facilities. The issue presents new opportunities for developing cheap high-flux membrane systems, deployable in low-to high-income economies, to remove small-sized microplastic and nanoplastics in wastewater. Here, we report on developing an ultra-high flux gravity-driven fabric membrane system, assessed through a laboratory-scale filtration and large-scale performance in an actual wastewater treatment plant (WWTP). The method followed a carefully designed water sampling, pre-treatment protocol, and analytical measurements involving Fourier transform infrared (FTIR) spectroscopy and laser direct infrared (LDIR) imaging. The result shows that the ultra-high flux (permeance = 550,000 L/m2h⋅bar) fabric membrane system can effectively remove small-sized microplastics (10–300 μm) in the secondary effluent of an actual WWTP at high efficiency greater than 96 %. The pilot system demonstrated a continuous treatment capacity of 300,000 L/day through a 1 m2 surface area disc, with steady removal rates of microplastics. These findings demonstrate the practical, cheap, and sustainable removal of small-sized microplastics in wastewater treatment plants, and their potential value for other large-scale point sources, e.g., stormwater treatment facilities. [Display omitted] • Gravity-driven fabric membrane achieved ultra-high flux filtration of WWTP secondary effluents. • The low transmembrane pressure supported permeance of about 550,000 L/m2h⸱bar. • The system results in 100% removal of large microplastics (300–5000 μm) from WWTP SE. • The system results in 96% removal of tiny microplastics (10–300 μm) from WWTP SE. • The system offers economical removal of small-sized microplastics in sizable point sources. [ABSTRACT FROM AUTHOR]

Among the countermeasures against combined sewer overflow (CSO), urban green space (UGS) has been proven effective. However, few studies have examined the effects of UGS on CSO at the municipal scale. Therefore, this study aimed to develop a novel method for estimating the relation of the area of UGS to CSO based on a case study in the Tokyo metropolitan area, which includes 10 sewersheds. This method integrates surface runoff modeling, sewer network analysis, and response analysis for estimating CSO and its response to the UGS proportion in each sewershed. This method is based on public data of topographic features, land-related data, and rainfall characteristics. Specifically, the CSO discharge is estimated to be the difference between the rainwater inflow to a terminal treatment plant and the maximum capacity of the sewer systems in each sewershed. The results revealed that the amount of CSO increases exponentially with the intensity of rainfall. In addition, a response analysis showed that the increase in UGS proportion would mitigate CSO in all sewersheds, particularly in the case where the UGS proportion increased from 5% to 10%. Overall, the present method allows us to estimate CSO in relation to rainfall pattern and the distribution of UGS in a sewershed without actual CSO records.

While the ecological benefits of no-till are largely indisputable, the economic impacts are less certain, and the latter may be partly to blame for lower-than-expected adoption of no-till. In this study, we contribute to a better understanding of the ecosystem and farm-level economic impacts of no-till, with Buchanan County in the northeastern region of the U.S. State of Iowa as the backdrop due to previously established data and model validation efforts in that region. Using the Agricultural Policy Environmental eXtender (APEX) and Farm Economic Model (FEM), we simulated two tillage scenarios—a conservation tillage baseline and no-till—for continuous corn and corn–soybean rotations in Buchanan County using gridded historical climate data. We find that no-till provides clear ecosystem benefits, except that soluble nutrient losses might actually rise. We also find that under current commodity prices for corn and soybeans, no-till is not as profitable as the conservation tillage baseline. For no-till to be at least as profitable as the baseline under current commodity prices, the yield penalty associated with no-till cannot be higher than 1.5% for corn and 0.8% for soybeans, or similar combinations that entail a revenue penalty of about $24,000 for an 809-hectare continuous corn or corn–soybean operation. Given the simulated yield penalties associated with no-till, corn and soybean prices would have to be substantially lower in order for no-till to break even. Consequently, incentives for conservation practice implementation may need to be tied to commodity prices and yield penalties in order to elicit greater adoption rates.

Agricultural pesticides transported to surface waters pose a major risk for aquatic ecosystems. Modelling studies indicate that the inlets of agricultural storm drainage systems can considerably increase the connectivity of surface runoff and pesticides to surface waters. These model results have however not yet been validated with field measurements. In this study, we measured discharge and concentrations of 51 pesticides in four out of 158 storm drainage inlets of a small Swiss agricultural catchment (2.8 km2) and in the receiving stream. For this, we performed an event-triggered sampling during 19 rain events and collected plot-specific pesticide application data. Our results show that agricultural storm drainage inlets strongly influence surface runoff and pesticide transport in the study catchment. The concentrations of single pesticides in inlets amounted up to 62 µg/L. During some rain events, transport through single inlets caused more than 10% of the stream load of certain pesticides. An extrapolation to the entire catchment suggests that during selected events on average 30 to 70% of the load in the stream was transported through inlets. Pesticide applications on fields with surface runoff or spray drift potential to inlets led to increased concentrations in the corresponding inlets. Overall, this study corroborates the relevance of such inlets for pesticide transport by establishing a connectivity between fields and surface waters, and by their potential to deliver substantial pesticide loads to surface waters. [ABSTRACT FROM AUTHOR]

[Objective] With a view to providing reference for the management of phosphorus (P) and potassium (K) and environmental assessment in the orchard, the nutrient balance and the environmental risk of P and K in mango orchards under optimized and reduced application of chemical fertilizer were examined.[Method] Seven fertilization treatments were conducted: (i) No fertilization (control, NF), (ii) Sole application of basal organic fertilizer (control, CF), (iii) Constant furrow application of chemical fertilizer (A), (iv) Combined furrow application of organic-inorganic fertilizer (OS), (v) Constant furrow application of integrated water fertilizer (IWF), (vi) 30% Reduced furrow application of water fertilizer (RA), (vii) Combined application of organic-inorganic water fertilizer (OWF) . The surface runoff test was performed on the basis of rainfall simulation experiments, and estimations were made grounded on local meteorological data; The environmental risk assessment test of P and K was carried out in virtue of laboratory tests under simulated conditions to determine the threshold of environmental sensitivity of P and K, thereby dividing the scale; Nutrient balance was utilized to analyze the surplus and deficit of P and K.[Result] The surplus rate of P earned the highest ranking, up to 63.36% (67.04 kg/hhm²), in the constant furrow application of chemical fertilizer (A) ; Maximum K surplus was recorded in the furrow application of chemical fertilizer (A), with a rate of 49.49% (142.96 kg/hhm²) ; The runoff losses of P and K in mango orchards attained to 10.74 kg/hhm² and 8.86 kg/hhm² respectively. The P output and corresponding proportion was ranged as follows: Pruned branches and leaves > surface runoff > litter > harvested fruits, while the sequence of K output and corresponding proportion was: Harvested fruits > prune branches and leaves > litter > surface runoff. The risk threshold of P for a single input was 45.99 kg/hhm², and that of K reached 20.29 kg/hhm². The environmental risk of P in soil was calculated to be 103.78 mg/kg, and that of K arrived at 143.98 mg/kg. The available phosphorus contents of such treatments as A, OS, IWF and OWF exceeded the environmental risk threshold, signaling the phosphorus losses. Similarly, the potassium losses should be noted in that the available potassium contents in OWF and IWF topped the environmental risk threshold. The available potassium content in OS approached the environmental risk threshold, which suggested the potential risk of potassium losses. [Conclusion] (i) Remarkable improvements in the availability of soil potassium and the absorption of potassium by fruit trees can be achieved in virtue of combined application of organic fertilizer. (ii) Measures should be adopted to conserve soil and water in light of the large proportion of phosphorus runoff losses to the phosphorus input in orchards. (iii) Compared with other fertilization treatments, 30% reduced furrow application of water fertilizer (RA) embodies the most balanced input of P and K in general, as well as pockets of improvement. Hence a certain proportion of organic fertilizer instead of chemical fertilizer input is recommended. (iv) It is advisable to keep a single input of P no more than 45.99 kg/hhm² considering the lower demand of mango trees for phosphorus and make K input less than or equal to 20.29 kg/hhm² each time despite the great demand for potassium, and nutrients can be supplied with low amounts and high frequency. [ABSTRACT FROM AUTHOR]

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