Search results for: surface runoff

Authors: Panagiotis Lemonakis, Theodoros Αlimonakis, George Kaliabetsos, Nikos Eliou

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It is very well known that certain vertical and longitudinal slopes have to be assured in order to achieve adequate rainwater runoff from the pavement. The selection of longitudinal slopes, between the turning points of the vertical curves that meet the afore-mentioned requirement does not ensure adequate drainage because the same condition must also be applied at the transition curves. In this way none of the pavement edges’ slopes (as well as any other spot that lie on the pavement) will be opposite to the longitudinal slope of the rotation axis. Horizontal and vertical alignment must be properly combined in order to form a road which resultant slope does not take small values and hence, checks must be performed in every cross section and every chainage of the road. The present research investigates the rain water runoff from the road surface in order to identify the conditions under which, areas of inadequate drainage are being created, to analyze the rainwater behavior in such areas, to provide design examples of good and bad drainage zones and to track down certain motorcycle types which might encounter hazardous situations due to the presence of water film between the pavement and both of their tires resulting loss of traction. Moreover, it investigates the combination of longitudinal and cross slope values in critical pavement areas. It should be pointed out that the drainage gradient is analytically calculated for the whole road width and not just for an oblique slope per chainage (combination of longitudinal grade and cross slope). Lastly, various combinations of horizontal and vertical design are presented, indicating the crucial zones of bad pavement drainage. The key conclusion of the study is that any type of motorcycle will travel for some time inside the area of improper runoff for a certain time frame which depends on the speed and the trajectory that the rider chooses along the transition curve. Taking into account that on this section the rider will have to lean his motorcycle and hence reduce the contact area of his tire with the pavement it is apparent that any variations on the friction value due to the presence of a water film may lead to serious problems regarding his safety. The water runoff from the road pavement is improved when between reverse longitudinal slopes, crest instead of sag curve is chosen and particularly when its edges coincide with the edges of the horizontal curve. Lastly, the results of the investigation have shown that the variation of the longitudinal slope involves the vertical shift of the center of the poor water runoff area. The magnitude of this area increases as the length of the transition curve increases.

Keywords: drainage, motorcycle safety, superelevation, transition curves, vertical grade

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Authors: Thomas Larm, Anna Wahlsten

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An international literature study has been carried out for comparison of commonly used methods for the dimensioning of transport systems and stormwater facilities for flow detention. The focus of the literature study regarding the calculation of design flow and detention has been the widely used Rational method and its underlying parameters. The impact of chosen design parameters such as return time, rain intensity, runoff coefficient, and climate factor have been studied. The parameters used in the calculations have been analyzed regarding how they can be calculated and within what limits they can be used. Data used within different countries have been specified, e.g., recommended rainfall return times, estimated runoff times, and climate factors used for different cases and time periods. The literature study concluded that the determination of runoff coefficients is the most uncertain parameter that also affects the calculated flow and required detention volume the most. Proposals have been developed for new runoff coefficients, including a new proposed method with equations for calculating runoff coefficients as a function of return time (years) and rain intensity (l/s/ha), respectively. Suggestions have been made that it is recommended not to limit the use of the Rational Method to a specific catchment size, contrary to what many design manuals recommend, with references to this. The proposed relationships between return time or rain intensity and runoff coefficients need further investigation and to include the quantification of uncertainties. Examples of parameters that have not been considered are the influence on the runoff coefficients of different dimensioning rain durations and the degree of water saturation of green areas, which will be investigated further. The influence of climate effects and design rain on the dimensioning of the stormwater facilities grassed ditches and biofilters (bio retention systems) has been studied, focusing on flow detention capacity. We have investigated how the calculated runoff coefficients regarding climate effect and the influence of changed (increased) return time affect the inflow to and dimensioning of the stormwater facilities. We have developed a smart design of ditches and biofilters that results in both high treatment and flow detention effects and compared these with the effect from dry and wet ponds. Studies of biofilters have generally before focused on treatment of pollutants, but their effect on flow volume and how its flow detention capability can improve is only rarely studied. For both the new type of stormwater ditches and biofilters, it is required to be able to simulate their performance in a model under larger design rains and future climate, as these conditions cannot be tested in the field. The stormwater model StormTac Web has been used on case studies. The results showed that the new smart design of ditches and biofilters had similar flow detention capacity as dry and wet ponds for the same facility area.

Keywords: runoff coefficients, flow detention, smart design, biofilter, ditch

Procedia PDF Downloads 59

Authors: Márcia Afonso, Cristina Fael, Marisa Dinis-Almeida

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Population growth in cities has led to an increase in the infrastructures construction, including buildings and roadways. This aspect leads directly to the soils waterproofing. In turn, changes in precipitation patterns are developing into higher and more frequent intensities. Thus, these two conjugated aspects decrease the rainwater infiltration into soils and increase the volume of surface runoff. The practice of green and sustainable urban solutions has encouraged research in these areas. The porous asphalt pavement, as a green infrastructure, is part of practical solutions set to address urban challenges related to land use and adaptation to climate change. In this field, permeable pavements with porous asphalt mixtures (PA) have several advantages in terms of reducing the runoff generated by the floods. The porous structure of these pavements, compared to a conventional asphalt pavement, allows the rainwater infiltration in the subsoil, and consequently, the water quality improvement. This green infrastructure solution can be applied in cities, particularly in streets or parking lots to mitigate the floods effects. Over the years, the pores of these pavements can be filled by sediment, reducing their function in the rainwater infiltration. Thus, double layer porous asphalt (DLPA) was developed to mitigate the clogging effect and facilitate the water infiltration into the lower layers. This study intends to deepen the knowledge of the performance of DLPA when subjected to clogging. The experimental methodology consisted on four evaluation phases of the DLPA infiltration capacity submitted to three precipitation events (100, 200 and 300 mm/h) in each phase. The evaluation first phase determined the behavior after DLPA construction. In phases two and three, two 500 g/m² clogging cycles were performed, totaling a 1000 g/m² final simulation. Sand with gradation accented in fine particles was used as clogging material. In the last phase, the DLPA was subjected to simple sweeping and vacuuming maintenance. A precipitation simulator, type sprinkler, capable of simulating the real precipitation was developed for this purpose. The main conclusions show that the DLPA has the capacity to drain the water, even after two clogging cycles. The infiltration results of flows lead to an efficient performance of the DPLA in the surface runoff attenuation, since this was not observed in any of the evaluation phases, even at intensities of 200 and 300 mm/h, simulating intense precipitation events. The infiltration capacity under clogging conditions decreased about 7% on average in the three intensities relative to the initial performance that is after construction. However, this was restored when subjected to simple maintenance, recovering the DLPA hydraulic functionality. In summary, the study proved the efficacy of using a DLPA when it retains thicker surface sediments and limits the fine sediments entry to the remaining layers. At the same time, it is guaranteed the rainwater infiltration and the surface runoff reduction and is therefore a viable solution to put into practice in permeable pavements.

Keywords: clogging, double layer porous asphalt, infiltration capacity, rainfall intensity

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Authors: Adilson Elias Xavier, Otto Corrêa Rotunno Filho, Paulo Canedo De Magalhães

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This paper addresses the issue of automatic parameter estimation in conceptual rainfall-runoff (CRR) models. Due to threshold structures commonly occurring in CRR models, the associated mathematical optimization problems have the significant characteristic of being strongly non-differentiable. In order to face this enormous task, the resolution method proposed adopts a smoothing strategy using a special C∞ differentiable class function. The final estimation solution is obtained by solving a sequence of differentiable subproblems which gradually approach the original conceptual problem. The use of this technique, called Hyperbolic Smoothing Method (HSM), makes possible the application of the most powerful minimization algorithms, and also allows for the main difficulties presented by the original CRR problem to be overcome. A set of computational experiments is presented for the purpose of illustrating both the reliability and the efficiency of the proposed approach.

Keywords: rainfall-runoff models, automatic calibration, hyperbolic smoothing method

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Authors: Ezequiel Garcia-Rodriguez, Lenin Hernandez-Ferreyra, Luis Ochoa-Franco

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The Sustainable Sewer Urban Systems (SSUS) are mechanisms integrated into the cities for manage rain water, reducing its runoff volume and velocity, enhancing the rain water quality and preventing flooding and other catastrophes associated to the rain, as well as improving the energy efficiency. The objective of SSUS is to mimic or to equal the runoff and infiltration natural conditions of the land before its urbanization, reducing runoff that may cause troubles within the houses, as well as flooding. At the same time, energy for warming homes and for pumping and treating water is reduced, contributing to the reduction of CO₂ emissions and therefore contributing to reduce the climate change. This paper contains an evaluation of the advantages that SSUS may offer within a zone of Morelia City, Mexico, applying support tools for decision making. The hydrological conditions prior to and after the urbanization of the study area were analyzed to propose the recommended SSUS. Different types of SSUS were proposed in this case study, assessing their effect on the rainwater flow behavior within the study area. SSUS usage in this case resulted, positively, in an important reduction of the magnitude and velocity of runoff, reducing therefore the risk of flooding. So that, it is recommended the implementation of SSUS in this case.

Keywords: energy efficiency, morelia, sustainablesewer, urban systems

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Authors: Salif Koné

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We analyze hydrometric data at the Koulikoro station on the Niger River; this basin drains 120600 km2 and covers three countries in West Africa, Guinea, Mali, and Ivory Coast. Two subsequent decadal cycles are highlighted (1925-1936 and 1929-1939) instead of the presumed single decadal one from literature. Moreover, the observed hydrometric data shows a multidecadal 40-year period that is confirmed when graphing a spatial coefficient of variation of runoff over decades (starting at 1901-1910). Spatial runoff data are produced on 48 grids (0.5 degree by 0.5 degree) and through semi-distributed versions of both SimulHyd model and GR2M model - variants of a French Hydrologic model – standing for Genie Rural of 2 parameters at monthly time step. Both extremal decades in terms of runoff coefficient of variation are confronted: 1951-1960 has minimal coefficient of variation, and 1981-1990 shows the maximal value of it during the three months of high-water level (August, September, and October). The mapping of the relative variation of these two decadal situations allows hypothesizing as following: the scale of variation between both extremal situations could serve to fix boundary conditions for further simulations using data from climate scenario.

Keywords: internal cycles, hydrometric data, niger river, gr2m and simulhyd framework, runoff coefficient of variation

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Authors: Oseni Taiwo Amoo, Bloodless Dzwairo

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In this paper, we extend the versatility and usefulness of GIS as a methodology for any river basin hydrologic characteristics analysis (HCA). The Gurara River basin located in North-Central Nigeria is presented in this study. It is an on-going research using spatial Digital Elevation Model (DEM) and Arc-Hydro tools to take inventory of the basin characteristics in order to predict water abstraction quantification on streamflow regime. One of the main concerns of hydrological modelling is the quantification of runoff from rainstorm events. In practice, the soil conservation service curve (SCS) method and the Conventional procedure called rational technique are still generally used these traditional hydrological lumped models convert statistical properties of rainfall in river basin to observed runoff and hydrograph. However, the models give little or no information about spatially dispersed information on rainfall and basin physical characteristics. Therefore, this paper synthesizes morphometric parameters in generating runoff. The expected results of the basin characteristics such as size, area, shape, slope of the watershed and stream distribution network analysis could be useful in estimating streamflow discharge. Water resources managers and irrigation farmers could utilize the tool for determining net return from available scarce water resources, where past data records are sparse for the aspect of land and climate.

Keywords: hydrological characteristic, stream flow, runoff discharge, land and climate

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Authors: Ahmed Abbas

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Land degradation in the Lower Cheliff region leads to loss of their fertility, physical and chemical properties by secondary salinization and film forming surface or surface crust. The main factor related to runoff and soil erosion is their susceptibility to crusting caused by the impact of raindrops, which causes the reduction of the filterability of the soil. The present study aims to investigate the hydrodynamic behavior of five types of soil taken from the plain of low Cheliff under simulated rainfall by using two intensities, one moderate, and others correspond to heavy rains at low kinetic energies. Experimental results demonstrate the influence of chemical and mechanical physical properties of soils on their hydrodynamic behavior and the influence of heavy rain on the modality of the reduction in the filterability and the amount of transported sediment.

Keywords: erosion, hydrodynamic behavior, rain simulation, soil

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Authors: Jie-Ying Wu, Kuo-Hao Weng, Jin-Cheng Fu

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This study proposes changes to land use for the purposes of water retention and runoff reduction, with the aim of reducing the frequency of flooding. This study uses the Zhuoshui River in Taiwan as a case study, designing different land use planning strategies, and setting up various detention spaces. The HEC-HMS model developed by the Hydrology Research Center of the U.S. Army Corps of Engineers is used to calculate the decrease in runoff using various planning strategies, during five precipitation events of increasing return periods. This study finds that a maximum decrease in runoff of 14 million square meters can result by changing the form of land cover and storm detention in non-urban agricultural and river zones. This is due to the fact that non-urban land accounts for 96% of the area under study. Greatest efficacy was demonstrated in a two-year return period, with results ranging from 16% to 52%. The efficacy of a 100-year return period rated from 3% to 8%. Urban area detentions consist of agricultural paddy fields, storm water ponds and rainwater retention systems in building basements. Although urban areas can provide one million cubic meters of runoff storage, this result is insignificant due to the fact that urban area constitutes only 4% of the study area. By changing land cover, a 2-year return period has a 9% efficacy, and a 100-year return period has a 2% efficacy.

Keywords: flood detention space, land-use, spatial planning, Zhuoshuei River, Taiwan

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Authors: J.Zambrano Nájera, M.Gómez Valentín

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Increases in urbanization during XX century, have brought as one major problem the increased of sediment production. Hydraulic erosion is one of the major causes of increasing of sediments in small urban catchments. Such increments in sediment yielding in header urban catchments can caused obstruction of drainage systems, making impossible to capture urban runoff, increasing runoff volumes and thus exacerbating problems of urban flooding. For these reasons, it is more and more important to study of sediment production in urban watershed for properly analyze and solve problems associated to sediments. The study of sediments production has improved with the use of mathematical modeling. For that reason, it is proposed a new physically based model applicable to small header urban watersheds that includes the advantages of distributed physically base models, but with more realistic data requirements. Additionally, in this paper the model proposed is compared with a lumped model, reviewing the results, the advantages and disadvantages between the both of them.

Keywords: erosion, hydrologic modeling, urban runoff, sediment modeling, sediment yielding, urban planning

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Authors: Joanna Fidelus-Orzechowska, Dominika Wronska-Walach, Jaroslaw Cebulski

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Mountain areas are very often exposed to numerous transformations connected with the development of tourist infrastructure. In mountain areas in Poland ski tourism is very popular, so agricultural areas are often transformed into tourist areas. The construction of new ski runs can change the direction and rate of slope development. The main aim of this research was to determine geomorphological and hydrological changes within slopes caused by ski run constructions. The study was conducted in the Remiaszów catchment in the Inner Polish Carpathians (southern Poland). The mean elevation of the catchment is 859 m a.s.l. and the maximum is 946 m a.s.l. The surface area of the catchment is 1.16 km2, of which 16.8% is the area of the two studied ski runs. The studied ski runs were constructed in 2014 and 2015. In order to determine the relief transformations connected with new ski run construction high resolution LIDAR data was analyzed. The general relief changes in the studied catchment were determined on the basis of ALS (Airborne Laser Scanning ) data obtained before (2013) and after (2016) ski run construction. Based on the two sets of ALS data a digital elevation models of differences (DoDs) was created, which made it possible to determine the quantitative relief changes in the entire studied catchment. Additionally, cross and longitudinal profiles were calculated within slopes where new ski runs were built. Detailed data on relief changes within selected test surfaces was obtained based on TLS (Terrestrial Laser Scanning). Hydrological changes within the analyzed catchment were determined based on the convergence and divergence index. The study shows that the construction of the new ski runs caused significant geomorphological and hydrological changes in the entire studied catchment. However, the most important changes were identified within the ski slopes. After the construction of ski runs the entire catchment area lowered about 0.02 m. Hydrological changes in the studied catchment mainly led to the interruption of surface runoff pathways and changes in runoff direction and geometry.

Keywords: hydrological changes, mountain areas, relief transformations, ski run construction

Procedia PDF Downloads 112

Authors: Muhammad B. Al Amin, Nyimas S. Rika, Dwi F. Yanto, Marcelina

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Siti Khadijah retention pond is located beside of Siti Khadijah Islamic Hospital on Demang Lebar Daun Street in Palembang City. This retention pond is functioned as storage for runoff from drainage channels in the surrounding area before entering Sekanak River, which is one of Musi River tributaries. However, in recent years, the developments in the surrounding area into paved area trigger to increase runoff discharge that causes the pond can no longer store it adequately. This study aimed to investigate the hydraulic performance of drainage system in the area around Siti Khadijah retention pond. A SWMM model was used to simulate runoff discharge into the pond and out from the pond, so the water level fluctuation within the pond and its capacity could be determined. Besides that, the water depth within drainage channels was simulated as well. The results showed that capacity of retention pond and some drainage channels already inadequate, so the area around it potentially to be flooded. Thus, it is necessary to increase the capacity of the retention pond and drainage channels.

Keywords: flood, retention pond, SWMM, urban drainage system

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Authors: S. Shamohammadi, L. Razavi

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This paper based on the principle concepts of SCS-CN model, a new mathematical model for computation of retention potential (S) presented. In the mathematical model, not only precipitation-runoff concepts in SCS-CN model are precisely represented in a mathematical form, but also new concepts, called “maximum retention” and “total retention” is introduced, and concepts of potential retention capacity, maximum retention, and total retention have been separated from each other. In the proposed model, actual retention (F), maximum actual retention (Fmax), total retention (S), maximum retention (Smax), and potential retention (Sp), for the first time clearly defined, so that Sp is not variable, but a function of morphological characteristics of the watershed. Indeed, based on the mathematical relation of the conceptual curve of SCS-CN model, the proposed model provides a new method for the computation of actual retention in watershed and it simply determined runoff based on. In the corresponding relations, in addition to Precipitation (P), Initial retention (Ia), cumulative values of actual retention capacity (F), total retention (S), runoff (Q), antecedent moisture (M), potential retention (Sp), total retention (S), we introduced Fmax and Fmin referring to maximum and minimum actual retention, respectively. As well as, ksh is a coefficient which depends on morphological characteristics of the watershed. Advantages of the modified version versus the original model include a better precision, higher performance, easier calibration and speed computing.

Keywords: model, mathematical, retention, watershed, SCS

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Authors: Hamid Fallah

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Undoubtedly, flood is known as a natural disaster, and in practice, flood is considered the most terrible natural disaster in the world both in terms of loss of life and financial losses. From 1988 to 1997, about 390,000 people were killed by natural disasters in the world, 58% of which were related to floods, 26% due to earthquakes, and 16% due to storms and other disasters. The total damages in these 10 years were about 700 billion dollars, which were 33, 29, 28% related to floods, storms and earthquakes, respectively. In this regard, the worrisome point has been the increasing trend of flood deaths and damages in the world in recent decades. The increase in population and assets in flood plains, changes in hydro systems and the destructive effects of human activities have been the main reasons for this increase. During rain and snow, some of the water is absorbed by the soil and plants. A percentage evaporates and the rest flows and is called runoff. Floods occur when the soil and plants cannot absorb the rainfall, and as a result, the natural river channel does not have the capacity to pass the generated runoff. On average, almost 30% of precipitation is converted into runoff, which increases with snow melting. Floods that occur differently create an area called flood plain around the river. River floods are often caused by heavy rains, which in some cases are accompanied by snow melt. A flood that flows in a river without warning or with little warning is called a flash flood. The casualties of these rapid floods that occur in small watersheds are generally more than the casualties of large river floods. Coastal areas are also subject to flooding caused by waves caused by strong storms on the surface of the oceans or waves caused by underground earthquakes. Floods not only cause damage to property and endanger the lives of humans and animals, but also leave other effects. Runoff caused by heavy rains causes soil erosion in the upstream and sedimentation problems in the downstream. The habitats of fish and other animals are often destroyed by floods. The high speed of the current increases the damage. Long-term floods stop traffic and prevent drainage and economic use of land. The supports of bridges, river banks, sewage outlets and other structures are damaged, and there is a disruption in shipping and hydropower generation. The economic losses of floods in the world are estimated at tens of billions of dollars annually.

Keywords: flood, hydrological engineering, gis, dam, small hydropower, suitablity

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Authors: H. H. Elewa, E. M. Ramadan, A. M. Nosair

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Rainfall water harvesting is considered as an important tool for overcoming water scarcity in arid and semi-arid region. Wadi Watir in the southeastern part of Sinai Peninsula is considered as one of the main and active basins in the Gulf of Aqaba drainage system. It is characterized by steep hills mainly consist of impermeable rocks, whereas the streambeds are covered by a highly permeable mixture of gravel and sand. A comprehensive approach involving the integration of geographic information systems, remote sensing and watershed modeling was followed to identify the RWH capability in this area. Eight thematic layers, viz volume of annual flood, overland flow distance, maximum flow distance, rock or soil infiltration, drainage frequency density, basin area, basin slope and basin length were used as a multi-parametric decision support system for conducting weighted spatial probability models (WSPMs) to determine the potential areas for the RWH. The WSPMs maps classified the area into five RWH potentiality classes ranging from the very low to very high. Three performed WSPMs' scenarios for W. Watir reflected identical results among their maps for the high and very high RWH potentiality classes, which are the most suitable ones for conducting surface water harvesting techniques. There is also a reasonable match with respect to the potentiality of runoff harvesting areas with a probability of moderate, low and very low among the three scenarios. WSPM results have shown that the high and very high classes, which are the most suitable for the RWH are representing approximately 40.23% of the total area of the basin. Accordingly, several locations were decided for the establishment of water harvesting dams and cisterns to improve the water conditions and living environment in the study area.

Keywords: Sinai, Wadi Watir, remote sensing, geographic information systems, watershed modeling, runoff water harvesting

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Authors: Kazuki Kohama, Hiroko Ono

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The rainfall in Japan is gradually increasing every year according to Japan Meteorological Agency and Intergovernmental Panel on Climate Change Fifth Assessment Report. It means that the rainfall difference between rainy season and non-rainfall is increasing. In addition, the increasing trend of strong rain for a short time clearly appears. In recent years, natural disasters have caused enormous human injuries in various parts of Japan. Regarding water disaster, local heavy rain and floods of large rivers occur frequently, and it was decided on a policy to promote hard and soft sides as emergency disaster prevention measures with water disaster prevention awareness social reconstruction vision. Okinawa prefecture in subtropical region has torrential rain and water disaster several times a year such as river flood, in which is caused in specific rivers from all 97 rivers. Also, the shortage of capacity and narrow width are characteristic of river in Okinawa and easily cause river flood in heavy rain. This study focuses on Kohatu River that is one of the specific rivers. In fact, the water level greatly rises over the river levee almost once a year but non-damage of buildings around. On the other hand in some case, the water level reaches to ground floor height of house and has happed nine times until today. The purpose of this research is to figure out relationship between precipitation, surface outflow and total treatment water quantity of Kohatu River. For the purpose, we perform hydrological analysis although is complicated and needs specific details or data so that, the method is mainly using Geographic Information System software and outflow analysis system. At first, we extract watershed and then divided to 23 catchment areas to understand how much surface outflow flows to runoff point in each 10 minutes. On second, we create Unit Hydrograph indicating the area of surface outflow with flow area and time. This index shows the maximum amount of surface outflow at 2400 to 3000 seconds. Lastly, we compare an estimated value from Unit Hydrograph to a measured value. However, we found that measure value is usually lower than measured value because of evaporation and transpiration. In this study, hydrograph analysis was performed using GIS software and outflow analysis system. Based on these, we could clarify the flood time and amount of surface outflow.

Keywords: disaster prevention, water disaster, river flood, GIS software

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Authors: Rosendo Mendoza, María Carmen Hidalgo, María José Campos-Suñol, Julián Martínez, Javier Rey

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The impact of mining environmental liabilities and mine drainage on surface water quality has been investigated in the hydrographic basin of the La Carolina mining district (southern Spain). This abandoned mining district is characterized by the existence of important mineralizations of sulfoantimonides of Pb - Ag, and sulfides of Cu - Fe. All surface waters reach the main river of this mining area, the Grande River, which ends its course in the Rumblar reservoir. This waterbody is intended to supply 89,000 inhabitants, as well as irrigation and livestock. Therefore, the analysis and control of the metal(loid) concentration that exists in these surface waters is an important issue because of the potential pollution derived from metallic mining. A hydrogeochemical campaign consisting of 20 water sampling points was carried out in the hydrographic network of the Grande River, as well as two sampling points in the Rumbler reservoir and at the main tailings impoundment draining to the river. Although acid mine drainage (pH below 4) is discharged into the Grande river from some mine adits, the pH values in the river water are always neutral or slightly alkaline. This is mainly the result of a dilution process of the small volumes of mine waters by net alkaline waters of the river. However, during the dry season, the surface waters present high mineralization due to a constant discharge from the abandoned flooded mines and a decrease in the contribution of surface runoff. The concentrations of dissolved Cd and Pb in the water reach values of 2 and 81 µg/l, respectively, exceeding the limit established by the Environmental Quality Standard for surface water. In addition, the concentrations of dissolved As, Cu, and Pb in the waters of the Rumblar reservoir reached values of 10, 20, and 11 µg/l, respectively. These values are higher than the maximum allowable concentration for human consumption, a circumstance that is especially alarming.

Keywords: environmental quality, hydrogeochemistry, metal mining, surface water

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Authors: Marzieh Khedmati, Shannon L. Bartelt-Hunt

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Vegetative Filter Strips (VFS) are used for controlling the volume of runoff and decreasing contaminant concentrations in runoff before entering water bodies. Many studies have investigated the role of VFS in sediment and nutrient removal, but little is known about their efficiency for the removal of emerging contaminants such as antimicrobial resistance genes (ARGs). Vegetative Filter Strip Modeling System (VFSMOD) was used to simulate the efficiency of VFS in this regard. Several studies demonstrated the ability of VFSMOD to predict reductions in runoff volume and sediment concentration moving through the filters. The objectives of this study were to calibrate the VFSMOD with experimental data and assess the efficiency of the model in simulating the filter behavior in removing ARGs (ermB) and tylosin. The experimental data were obtained from a prior study conducted at the University of Nebraska (UNL) Rogers Memorial Farm. Three treatment factors were tested in the experiments, including manure amendment, narrow grass hedges and rainfall events. Sediment Delivery Ratio (SDR) was defined as the filter efficiency and the related experimental and model values were compared to each other. The VFS Model generally agreed with the experimental results and as a result, the model was used for predicting filter efficiencies when the runoff data are not available. Narrow Grass Hedges (NGH) were shown to be effective in reducing tylosin and ARGs concentration. The simulation showed that the filter efficiency in removing ARGs is different for different soil types and filter lengths. There is an optimum length for the filter strip that produces minimum runoff volume. Based on the model results increasing the length of the filter by 1-meter leads to higher efficiency but widening beyond that decreases the efficiency. The VFSMOD, which was proved to work well in estimation of VFS trapping efficiency, showed confirming results for ARG removal.

Keywords: antimicrobial resistance genes, emerging contaminants, narrow grass hedges, vegetative filter strips, vegetative filter strip modeling system

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Authors: Dan Qu, Dezhi Sun, Benhang Li

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The removal of Nitenpyram from farmland runoff by an integrated eco-ditches and constructed wetland system was investigated in the case of different HRT. Experimental results show that the removal of COD, N and P was not influenced by the Nitenpyram. When the HRT was 2.5 d, 2 d, and 1 d, the Nitenpyram removal efficiency could reach 100%, 100% and 84%, respectively. The removal efficiency in the ecological ditches was about 38%-40% in the case of different HRT, while that in the constructed wetland was influenced by the HRT variation. The optimum HRT for Nitenpyram and pollutants removal was 2 d. The substrate zeolite with soil and hollow brick layer enabled higher Nitenpyram removal rates, probably due to the cooperative phenomenon of plant uptake and microbiological deterioration as well as the adsorption by the substrate.

Keywords: ecological ditch, vertical flow constructed wetland, hydraulic retention time, Nitenpyram

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Authors: Austin P. Hopkins, R. Daren Harmel, Jim A Ippolito, P. J. A. Kleinman, D. Sahoo

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Field-scale runoff and water quality data are critical to understanding the fate and transport of nutrients applied to agricultural lands and minimizing their off-site transport because it is at that scale that agricultural management decisions are typically made based on hydrologic, soil, and land use factors. However, regional influences such as precipitation, temperature, and prevailing cropping systems and land use patterns also impact nutrient runoff. In the present study, the recently-updated MANAGE (Measured Annual Nutrient loads from Agricultural Environments) database was used to conduct an ecoregion-level analysis of nitrogen and phosphorus runoff from agricultural lands in the North America. Specifically, annual N and P runoff loads for cropland and grasslands in North American Level II EPA ecoregions were presented, and the impact of factors such as land use, tillage, and fertilizer timing and placement on N and P runoff were analyzed. Specifically we compiled annual N and P runoff load data (i.e., dissolved, particulate, and total N and P, kg/ha/yr) for each Level 2 EPA ecoregion and for various agricultural management practices (i.e., land use, tillage, fertilizer timing, fertilizer placement) within each ecoregion to showcase the analyses possible with the data in MANAGE. Potential differences in N and P runoff loads were evaluated between and within ecoregions with statistical and graphical approaches. Non-parametric analyses, mainly Mann-Whitney tests were conducted on median values weighted by the site years of data utilizing R because the data were not normally distributed, and we used Dunn tests and box and whisker plots to visually and statistically evaluate significant differences. Out of the 50 total North American Ecoregions, 11 were found that had significant data and site years to be utilized in the analysis. When examining ecoregions alone, it was observed that ER 9.2 temperate prairies had a significantly higher total N at 11.7 kg/ha/yr than ER 9.4 South Central Semi Arid Prairies with a total N of 2.4. When examining total P it was observed that ER 8.5 Mississippi Alluvial and Southeast USA Coastal Plains had a higher load at 3.0 kg/ha/yr than ER 8.2 Southeastern USA Plains with a load of 0.25 kg/ha/yr. Tillage and Land Use had severe impacts on nutrient loads. In ER 9.2 Temperate Prairies, conventional tillage had a total N load of 36.0 kg/ha/yr while conservation tillage had a total N load of 4.8 kg/ha/yr. In all relevant ecoregions, when corn was the predominant land use, total N levels significantly increased compared to grassland or other grains. In ER 8.4 Ozark-Ouachita, Corn had a total N of 22.1 kg/ha/yr while grazed grassland had a total N of 2.9 kg/ha/yr. There are further intricacies of the interactions that agricultural management practices have on one another combined with ecological conditions and their impacts on the continental aquatic nutrient loads that still need to be explored. This research provides a stepping stone to further understanding of land and resource stewardship and best management practices.

Keywords: water quality, ecoregions, nitrogen, phosphorus, agriculture, best management practices, land use

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Authors: R. Sarjahani, M. Sheikhattar, S. Javadpour, B. Hashemi

Abstract:

Glazes and their surface characterization is an important subject for ceramic industries. Fabrication of a super smooth surface resistant to stains is a big improvement for those industries. In this investigation, surface topography of popular glazes such as Zircon and Titania based opaque glazes, calcium based matte glaze and transparent glaze has been analyzed by Marsurf M300, SEM, EDS and XRD. Results shows that surface roughness of glazes seriously depends on surface crystallinity, crystal size and shapes.

Keywords: crystallinity, glaze, surface roughness, topography

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Authors: Nana Bolashvili, Vakhtang Geladze, Tamazi Karalashvili, Nino Machavariani, George Geladze, Davit Kartvelishvili, Ana Karalashvili

Abstract:

Fresh water is the major natural resource of Georgia. The average perennial sum of the rivers' runoff in Georgia is 52,77 km³, out of which 9,30 km³ inflows from abroad. The major volume of transit river runoff is ascribed to the Chorokhi river. Average perennial runoff in Western Georgia is 41,52 km³, in Eastern Georgia 11,25 km³. The indices of Eastern and Western Georgia were calculated with 50% and 90% river runoff respectively, while the same index calculation for other countries is based on a 50% river runoff. Out of total volume of resources, 133,2 m³/sec (4,21 km³) has been geologically prospected by the State Commission on Reserves and Acknowledged as reserves available for exploitation, 48% (2,02 km³) of which is in Western Georgia and 2,19 km³ in Eastern Georgia. Considering acknowledged water reserves of all categories per capita water resources accounts to 2,2 m³/day, whereas high industrial category -0. 88 m³ /day fresh drinking water. According to accepted norms, the possibility of using underground water reserves is 2,5 times higher than the long-term requirements of the country. The volume of abundant fresh-water reserves in Georgia is about 150 m³/sec (4,74 km³). Water in Georgia is consumed mostly in agriculture for irrigation purposes. It makes 66,4% around Georgia, in Eastern Georgia 72,4% and 38% in Western Georgia. According to the long-term forecast provision of population and the territory with water resources in Eastern Georgia will be quite normal. A bit different is the situation in the lower reaches of the Khrami and Iori rivers which could be easily overcome by corresponding financing. The present day irrigation system in Georgia does not meet the modern technical requirements. The overall efficiency of their majority varies between 0,4-0,6. Similar is the situation in the fresh water and public service water consumption. Organization of the mentioned systems, installation of water meters, introduction of new methods of irrigation without water loss will substantially increase efficiency of water use. Besides new irrigation norms developed from agro-climatic, geographical and hydrological angle will significantly reduce water waste. Taking all this into account we assume that for irrigation agricultural lands in Georgia is necessary 6,0 km³ water, 5,5 km³ of which goes to Eastern Georgia on irrigation arable areas. To increase water supply in Eastern Georgian territory and its population is possible by means of new water reservoirs as the runoff of every river considerably exceeds the consumption volume. In conclusion, we should say that fresh water resources by which Georgia is that rich could be significant source for barter exchange and investment attraction. Certain volume of fresh water can be exported from Western Georgia quite trouble free, without bringing any damage to population and hydroecosystems. The precise volume of exported water per region/time and method/place of water consumption should be defined after the estimation of different hydroecosystems and detailed analyses of water balance of the corresponding territories.

Keywords: GIS, management, rivers, water resources

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Authors: Sakura Yoshii, Masakazu Abe, Akihiro Iijima

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Nitrogen saturation has become one of the serious issues in the field of forest environment. The watershed protection forests located in the downwind hinterland of Tokyo Metropolitan Area are believed to be facing nitrogen saturation. In this study, we carefully focus on the balance of nitrogen between load and runoff. Annual nitrogen load via atmospheric deposition was estimated to 461.1 t-N/year in the upper reaches of the Kanna River. Annual nitrogen runoff to the forested headwater stream of the Kanna River was determined to 184.9 t-N/year, corresponding to 40.1% of the total nitrogen load. Clear seasonal change in NO3-N concentration was still observed. Therefore, watershed protection forest of the Kanna River is most likely to be in Stage-1 on the status of nitrogen saturation.

Keywords: atmospheric deposition, nitrogen accumulation, denitrification, forest ecosystems

Procedia PDF Downloads 246

Authors: Mohamed Emran, Giovanni Pardini, Maria Gispert, Mohamed Rashad

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Land use and abandonment in semi-arid degraded ecosystems may cause regressive dynamics in vegetation cover affecting organic matter contents, soil nutrients and structural stability, thus reducing soil resistance to erosion. Mediterranean areas are generally subjected to climatic fluctuations, which modify soil conditions and hydrological processes, such as runoff and water infiltration within the upper soil horizons. Low erosion rates occur in very fragile and shallow soils with minor clay content progressively decrease organic carbon C and nitrogen N pools in the upper soil horizons. Seven soils were selected representing variant context of land use and abandonment at the Cap de Creus Peninsula, Catalonia, NE Spain, from recent cultivated vines and olive groves, mid abandoned forests standing under cork and pine trees, pasture to late abandoned Cistus and Erica scrubs. The aim of this work was to study the effect of changes in land use and abandonment on the depletion of soil organic carbon and nitrogen transported by runoff water in shallow soils after natural rainfall events during two years with different rainfall patterns (1st year with low rainfall and 2nd year with high rainfall) by i) monitoring the most significant soil erosion parameters at recorded rainfall events, ii) studying the most relevant soil physical and chemical characteristics on seasonal basis and iii) analysing the seasonal trends of depleted carbon and nitrogen and their interaction with soil surface compaction parameters. Significant seasonal variability was observed in the relevant soil physical and chemical parameters and soil erosion parameters in all soils to establish their evolution under land use and abandonment during two years of different rainfall patterns (214 and 487 mm per year), giving important indications on soil response to rainfall impacts. Erosion rates decreased significantly with the increasing of soil C and N under low and high rainfall. In cultivated soils, C and N depletion increased by 144% and 115%, respectively by 13% increase in erosion rates during the 1st year with respect to the 2nd year. Depleted C and N were proportionally higher in soils under vines and olive with vulnerable soil structure and low soil resilience leading to degradation, altering nutrients cycles and causing adverse impact on environmental quality. Statistical analysis underlined that, during the 1st year, soil surface was less effective in preserving stocks of organic resources leading to higher susceptibility to erosion with consequent C and N depletion. During the 2nd year, higher organic reserve and water storage occurred despite the increasing of C and N loss with an effective contribution from soil surface compaction parameters. The overall estimation during the two years indicated clear differences among soils under vines, olive, cork and pines, suggesting on the one hand, that current cultivation practices are inappropriate and that reforestation with pines may delay the achievement of better soil conditions. On the other hand, the natural succession of vegetation under Cistus, pasture and Erica suggests the recovery of good soil conditions.

Keywords: land abandonment, land use, nutrient's depletion, soil erosion

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Authors: Leonard Chimaobi Agim, Charles Arinzechukwu Igwe, Emmanuel Uzoma Onweremadu, Gabreil Osuji

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Soil erosion has been linked to stream sedimentation, ecosystem degradation, and loss of soil nutrients. A study was conducted to evaluate the effect of some organic amendment on sediment yield, splash loss, and runoff of soils of selected parent materials in southeastern Nigeria. A total of 20 locations, five from each of four parent materials namely: Asu River Group (ARG), Bende Ameki Group (BAG), Coastal Plain Sand (CPS) and Falsebedded Sandstone (FBS) were used for the study. Collected soil samples were analyzed with standard methods for the initial soil properties. Rainfall simulation at an intensity of 190 mm hr-1was conducted for 30 minutes on the soil samples at both the initial stage and after amendment to obtain erosion parameters. The influence of parent material on sediment yield, splash loss and runoff based on rainfall simulation was tested for using one way analyses of variance, while the influence of organic material and their combinations were a factorially fitted in a randomized complete block design. The organic amendments include; goat dropping (GD), poultry dropping (PD), municipal solid waste (MSW) and their combinations (COA) applied at four rates of 0, 10, 20 and 30 t ha-1 respectively. Data were analyzed using analyses of variance suitable for a factorial experiment. Significant means were separated using LSD at 5 % probability levels. Result showed significant (p ≤ 0.05) lower values of sediment yield, splash loss and runoff following amendment. For instance, organic amendment reduced sediment yield under wet and dry runs by 12.91 % and 26.16% in Ishiagu, 40.76% and 45.67%, in Bende, 16.17% and 50% in Obinze and 22.80% and 42.35% in Umulolo respectively. Goat dropping and combination of amendment gave the best results in reducing sediment yield.

Keywords: organic amendment, parent material, rainfall simulation, soil erosion

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Authors: Kourosh Nazarian

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Many of the engineering materials, such as behavioral metals, have at least a certain level of linear behavior. It means that if the stresses are doubled, the deformations would be also doubled. In fact, these materials have linear elastic properties. Soils do not follow this law, for example, when compressed, soils become gradually tighter. On the surface of the ground, the sand can be easily deformed with a finger, but in high compressive stresses, they gain considerable hardness and strength. This is mainly due to the increase in the forces among the separate particles. Creeps also deform the soils under a constant load over time. Clay and peat soils have creep behavior. As a result of this phenomenon, structures constructed on such soils will continue their collapse over time. In this paper, the researchers analyzed and modeled the stresses and creeps in the southern plains of Kerman province in Iran through library-documentary, quantitative and software techniques, and field survey. The results of the modeling showed that these plains experienced severe stresses and had a collapse of about 26 cm in the last 15 years and also creep evidence was discovered in an area with a gradient of 3-6 degrees.

Keywords: Stress, creep, faryab, surface runoff

Procedia PDF Downloads 136

Authors: Chansheng He, Lanhui Zhang, Baoqing Zhang

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Spatial heterogeneity of landscape significantly affects watershed hydrological processes, particularly in high elevation and cold mountainous watersheds such as the inland river (terminal lake) basins in Northwest China, where the upper reach mountainous areas are the main source of streamflow for the downstream agricultural oases and desert ecosystems. Thus, it is essential to take into account spatial variations of hydrological processes in streamflow allocation at the watershed scale. This paper adapts the Distributed Large Basin Runoff Model (DLBRM) to the Heihe River Watershed, the second largest inland river with a drainage area of about 128,000 km2 in Northwest China, for understanding the transfer and partitioning mechanism among the glacier and snowmelt, surface runoff, evapotranspiration, and groundwater recharge among the upper, middle, and lower reaches in the study area. Results indicate that the upper reach Qilian Mountain area is the main source of streamflow for the middle reach agricultural oasis and downstream desert areas. Large withdrawals for agricultural irrigation in the middle reach had significantly depleted river flow for the lower reach desert ecosystems. Innovative conservation and enforcement programs need to be undertaken to ensure the successful implementation of water allocation plan of delivering 0.95 x 109 m3 of water downstream annually by the State Council in the Heihe River Watershed.

Keywords: DLBRM, Northwestern China, spatial variation, water allocation

Procedia PDF Downloads 272

Authors: A. Caicedo Padilla, J. Zambrano Nájera

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Cali, the capital of Valle del Cauca and the second city of Colombia, is located in the Cauca River Valley between the Western and Central Cordillera that is South West of the country. The topography of the city is mainly flat, but it is possibly to find mountains in the west. The city has increased urbanization during XX century, especially since 1958 when started a rapid growth due to migration of people from other parts of the region. Much of that population has settled in eastern of Cali, an area originally intended for cane cultivation and a zone of flood from Cauca River and its tributaries. Due to the unplanned migration, settling was inadequate and produced changes in natural dynamics of the basins, which has resulted in increases in runoff volumes, peak flows and flow velocities, that in turn increases flood risk. Sewerage networks capacity were not enough for this higher runoff volume, because in first term they were not adequately designed and built, causing its failure. This in turn generates increasingly recurrent floods generating considerable effects on the economy and development of normal activities in Cali. Thus, it becomes very important to know hydrological behavior of Urban Watersheds. This research aims to determine the impact of urbanization on hydrology of watersheds with very low slopes. The project aims to identify changes in natural drainage patterns caused by the changes made on landscape. From the identification of such modifications it will be defined the most critical areas due to recurring flood events in the city of Cali. Critical areas are defined as areas where the sewerage system does not work properly as surface runoff increases considerable with storm events, and floods are recurrent. The assessment will be done from the analysis of Geographic Information Systems (GIS) theme layers from CVC Environmental Institution of Regional Control in Valle del Cauca, hydrological data and disaster database developed by OSSO Corporation. Rainfall data from a network and historical stream flow data will be used for analysis of historical behavior and change of precipitation and hydrological response according to homogeneous zones characterized by EMCALI S.A. public utility enterprise of Cali in 1999.

Keywords: drainage systems, land cover changes, urban hydrology, urban planning

Procedia PDF Downloads 226

Authors: Abrha Ybeyn Gebremedhn, Yitea Seneshaw Getahun, Alebachew Shumye Moges, Fikrey Tesfay

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Rainfed agriculture in Ethiopia has failed to produce enough food, to achieve the increasing demand for food. Pinpointing the appropriate site for rainwater harvesting (RWH) have a substantial contribution to increasing the available water and enhancing agricultural productivity. The current study related to the identification of the potential RWH sites was conducted at the Chacha watershed central highlands of Ethiopia which is endowed with rugged topography. The Geographic Information System with Analytical Hierarchy Process was used to generate the different maps for identifying appropriate sites for RWH. In this study, 11 factors that determine the RWH locations including slope, soil texture, runoff depth, land cover type, annual average rainfall, drainage density, lineament intensity, hydrologic soil group, antecedent moisture content, and distance to the roads were considered. The overall analyzed result shows that 10.50%, 71.10%, 17.90%, and 0.50% of the areas were found under highly, moderately, marginally suitable, and unsuitable areas for RWH, respectively. The RWH site selection was found highly dependent on a slope, soil texture, and runoff depth; moderately dependent on drainage density, annual average rainfall, and land use land cover; but less dependent on the other factors. The highly suitable areas for rainwater harvesting expansion are lands having a flat topography with a soil textural class of high-water holding capacity that can produce high runoff depth. The application of this study could be a baseline for planners and decision-makers and support any strategy adoption for appropriate RWH site selection.

Keywords: runoff depth, antecedent moisture condition, AHP, weighted overlay, water resource

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Authors: C. Agrawal, R. Kumar, A. Gupta, B. Chatterjee

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An experimental investigation has been carried out to study the cooling of a hot horizontal Stainless Steel surface of 3 mm thickness, which has 800±10 °C initial temperature. A round water jet of 22 ± 1 °C temperature was injected over the hot surface through straight tube type nozzles of 2.5-4.8 mm diameter and 250 mm length. The experiments were performed for the jet exit to target surface spacing of 4 times of jet diameter and jet Reynolds number of 5000-24000. The effect of change in jet Reynolds number on the surface quenching has been investigated form the stagnation point to 16 mm spatial location.

Keywords: hot-surface, jet impingement, quenching, stagnation point

Procedia PDF Downloads 575