Top PDF SWAT use of gridded observations for simulating runoff – a Vietnam river basin study

SWAT use of gridded observations for simulating runoff – a Vietnam river basin study

SWAT use of gridded observations for simulating runoff – a Vietnam river basin study

in addition requiring the wind speed. Due to limitations in the available meteorological data, the Hargreaves method is applied in this study. In the SWAT model, the land area in a sub-basin is divided into what are known as Hydrological Response Units (HRUs). In other words, a HRU is the smallest portion that combines different land use and soil type by overlaying their spatial map. All processes such as surface runoff, PET, lateral

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SWAT use of gridded observations for simulating runoff – a Vietnam river basin study

SWAT use of gridded observations for simulating runoff – a Vietnam river basin study

2001–2005. Some analyses have been carried out to com- pare those observational gridded datasets against station data. Figure 4 displays the monthly average annual precipitation cycle and the statistical box plots for the 6 gridded obser- vation datasets compared against observed station data. The annual cycle, as seen from the figure, is very useful to eval- uate the seasons through the year. It is normally estimated from observational data or model output by taking the av- erage of each month for a given number of years. This is a useful way of comparing the model and observations and is being used in many studies to compare data and trends (Pe- ter et al., 2009). It is clearly seen from the pattern of pre- cipitation annual cycle over these 3 rainfall stations that the observed data in black line shows that the Southwest mon- soon season (from May to September) brings more rain to this region with a peak of rainfall in August. APHRODITE (blue) and PERSIANN (red) follow closely with observed pattern. GPCP (cyan) is slightly lagging in mimicking the peak of the rainfall. The TRMM (green) and GHCN2 (ma- genta) data are not as good when compared to the other 3 datasets. The NCEP/NCAR reanalysis data (yellow) per- forms poorly, probably due to its coarse spatial resolution. The box plot is an efficient statistical method for displaying a five-number data summary: median, upper quartile (75th per- centile), lower quartile (25th percentile), minimum and max- imum value. The range of the middle two quartiles is called an inter-quartile range represented by a rectangle and if the median line in the box is not equidistant from the hinges then data is supposed to be skewed. The average monthly for 5- yr period precipitation box plots over 3 rainfall stations for 6 datasets are plotted in Fig. 4. Looking at the inter-quartile range of the gridded datasets compared to the station data, the APHRODITE and GPCP have the same range at the 3 stations while PERSIANN, TRMM and GHCN2 are slightly narrower with NCEP having the lowest range amongst them all and these showcase the uncertainties among them.
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Assessment of spatial and temporal patterns of green and blue water flows under natural conditions in inland river basins in Northwest China

Assessment of spatial and temporal patterns of green and blue water flows under natural conditions in inland river basins in Northwest China

al., 2009; Schuol et al., 2008) and quality (Gassman et al., 2007) assessments for a wide range of scales and environ- mental conditions, including green/blue water assessments; secondly, the SWAT model has been used to simulate the hydrological processes in a small upstream segment of the Heihe river basin successfully (Huang and Zhang, 2004; Li et al., 2009). There are more than nine types of hydrological models that have been used in the Heihe river basin for wa- ter resources research (Li, 2009). Nevertheless, all of these model simulations have focused on upstream river segments in the Qilian Mountains, which form only 14.7 % of the to- tal river basin area. The hydrological processes have never been studied for the entire river. An important reason is that past research on hydrological cycles is often focused on hu- man water use, particularly blue water use, thus overlook- ing water use by ecosystems. The up- and middle segments are regions where blue water is generated and used, but the downstream segments and surrounding areas are dominated by natural ecosystems and a low population density. Hence, most of the studies have focused on simulating upstream seg- ments and not the entire basin or downstream watersheds. However, we argue that studying the hydrological processes for the entire basin is essential since water is not only re- quired by human beings but also needed by natural ecosys- tems. In addition, a study covering the entire basin makes more sense from a hydrological point of view. An additional reason for the emphasis on upper river segments may also be the lack of available data for the downstream river segments. In our research, we use SWAT2005, which was running on Arcview 3.3 with a daily time step. In SWAT the modelled area is divided into multiple sub-basins and hydrological re- sponse units (HRUs) by overlaying elevation, land cover, soil, and slope classes. The HRUs are characterized by com- binations of dominant land-use, soil, and slope classes. This choice was essential for keeping the size of the model at a practical limit. For each of the sub-basins, water balance was simulated for four storage volumes: snow, soil profile, shal- low aquifer, and deep aquifer. Potential evapotranspiration was computed using the Hargreaves method (Hargreaves et al., 1985). The calculation of evaporation requires the input of daily precipitation, and minimum and maximum temper- ature. Surface runoff was simulated using a modified SCS curve number (CN) method and snow and melting water cal- culated by the energy balance equation. Further technical model details are given by Neitsch et al. (2004). The pre- processing of the SWAT model input was performed within ESRI Arc-GIS 9.3.
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RBRH  vol.22

RBRH vol.22

Changes in the Earth’s landscape have been the focus of much environmental research. In this context, hydrological models stand out as tools for several assessments. This study aimed to use the Soil and Water Assessment Tool (SWAT) hydrological model to simulate the impact of changes in land use in the Camboriú River Watershed in the years 1957, 1978, and 2012. The results indicated that the SWAT model was eficient in simulating water low and sediment transport processes. Thus, it was possible to evaluate the impact of different land use scenarios on water and sediment yield in the catchment. The changes in land use caused signiicant changes in the hydro-sedimentological dynamic. Regarding low, the effects of land use changes were more pronounced at both ends of the curve representing duration of low. The worst scenario was identiied for the year 2012, which saw the highest peak discharges during lood events and lowest lows during the dry season. Concerning soil erosion, the highest values were identiied for sub-basins that were predominantly covered by rice paddies and pastures; this was attributed mainly to surface runoff and changes in land use (represented by C-USLE). Overall, the Camboriú River Basin did not experience severe soil erosion issues; however, it was found that changes in land use related to soil and climate characteristics may increase soil degradation, especially in years with high precipitation levels. Keywords: Land use; Basin; Hydrologic scenarios.
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Soil Erosion Prediction Based on Land Use Changes (A Case in Neka Watershed)

Soil Erosion Prediction Based on Land Use Changes (A Case in Neka Watershed)

spatially distributed input data (geology, soil and land use) in a Geographic Information Systems (GIS) environment [20,22,23] . Using GIS technique is based on calibrated values of four basic factors which influence erosion rate: (a) Climate (precipitation and temperature), (b) Vegetation (type and distribution), (c) Relief (difference in elevation; slope angle) and (d) Soil and rocks properties (erodibility and porosity). To calibrate of these factors we need to prepare some data such as field survey, map digitization, extensive data processing and model validation. The process of erosion estimation and sediment transport would be significantly simpler by using aerial photographs and satellite data, digital and thematic maps. This study applied GIS as a priority technique in watershed management to identify and quantitative classification for an extensive area with a similar pattern of erosion. This would require to produce a Digital Elevation Model (DEM) and identifying the area with a similar conditions such as geological and vegetation characteristics. The final creation would be a multi- layer map to identify area with a similar erosion patterns. The EPM gives an efficient combination of physical parameters such as geology (y coefficient), soil dynamics (Ψ coefficient) and vegetation (Xa coefficient) contribution. In this study, EPM model and analytical GIS tools used for the land management in order to erosion reduction in the study area. Land use changes related to the slop factor is capable to reduce the rate of erosion up to 89.24%.
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Assessing water footprint at river basin level: a case study for the Heihe River Basin in northwest China

Assessing water footprint at river basin level: a case study for the Heihe River Basin in northwest China

ence of WF within the river basin. Spatial heterogeneity of climate conditions and land use/cover are very sharp in the HRB with high precipitation and glaciers upstream and low precipitation and desert downstream. There is a need to compare WF with water availability at the sub-basin levels. This is out of the scope of this paper, but it is what will be further investigated in the next step. Last but not least, there is also a need to

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A hydrological-modeling study of the impact of land use/land cover and climate change on runoff in a watershed in the western Brazilian Amazonia |  Um estudo de modelagem hidrológica do impacto do uso da terra / cobertura da terra e mudanças climáticas ..

A hydrological-modeling study of the impact of land use/land cover and climate change on runoff in a watershed in the western Brazilian Amazonia | Um estudo de modelagem hidrológica do impacto do uso da terra / cobertura da terra e mudanças climáticas ..

quite evident. In the 100% Forest scenario, transpiration responds for almost the total evapotranspiration. This is intuitive, since in such a scenario, the interaction between surface and the free atmosphere is dominated by the exchange processes at the vegetation canopy. In the non-forest scenario, the soil cover formed by Savannah, pasture and water causes the transpiration to be twice the direct evaporation. In the man-modified scenario, the soil with urban-deforested characteristic implies in an evaporation contribution greater than the transpiration one. In the realistic scenarios, one can observe that, compared with the actual case, evapotranspiration decreases slightly and groundwater decreases less with the decrease of the forested area. Accordingly, transpiration also decreases as the forested area is reduced by 20% and 30%, respectively and ground water all decreases by 20% and 8%, respectively. Since deforestation leads to less interception of water by vegetation, the contribution of evaporation increases as the cover of bare soil becomes larger.
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Modeling runoff response to land-use changes using the SWAT model in the Mundaú watershed, Brazil

Modeling runoff response to land-use changes using the SWAT model in the Mundaú watershed, Brazil

Land-use change has a significant influence on runoff process of any watershed, and the deepening of this theme is essential to assist decision making, within the scope of water resources management. The study was conducted for Mundaú River Basin (MRB) using the Soil and Water Assessment Tool (SWAT) model. The study aims to assess the issue of land-use change and its effect on evapotranspiration, surface runoff, and sediment yield. Input data like land use, topography, weather, and soil data features are required to undertake watershed simulation. Two scenarios of land use were analyzed over 30 years, which were: a regeneration scenario (referring to use in the year 1987) and another scene of degradation (relating to use in the year 2017). Land use maps for 1987 and 2017 were acquired from satellite images. Overall, during the last three decades, 76.4% of forest was lost in the MRB. The grazing land increased in 2017 at a few more than double the area that existed in 1987. Changes in land use, over the years, resulted in an increase of about 37% in the water yield of MRB. Changes have led to increased processes such as surface runoff and sediment yield and in the decrease of evapotranspiration. The spatial and temporal distribution of land use controls the water balance and sediment production in the MRB.
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Lineament and Morphometric Analysis for Watershed Development of Tarali River Basin, Western India

Lineament and Morphometric Analysis for Watershed Development of Tarali River Basin, Western India

In India day by day demand of water is increasing due to growing population, increasing industrialization, rapid urbanization and agricultural irrigation. The demand for water multiplying is leading to the scarcity problem. The water scarcity is also increasing problem of water pollution and over exploitation of groundwater in certain areas. Due to rainfall variation and water deficiency at some places water is supplied with the help of tankers. Thus, management of water resource is essential. In this regard neo-tectonic activities were studied with the help of lineament and morphometric analysis of Tarali River basin which is tributary of Krishna River Basin, western India. The neo-tectonics indicates faulting and upliftment of landmass form during recent years which controls geomorphology of area and also drainage patterns. Geomorphological and tectonic settlement of area helps in various factors which is useful for management and planning of basin development. Drainage morphometry will signifying the construction sites for artificial recharging structures for implication of hydrology (Golekar et al, 2013 and Babar, 2005).
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Groundwater recharge behavior based on surface runoff hydrographs in two basins of the Minas Gerais State

Groundwater recharge behavior based on surface runoff hydrographs in two basins of the Minas Gerais State

Estimation of the recharge rates can be performed based on data sets of discharges with the hydrograph components separated, being the most common estimates based upon groundwater flow, or base flow (Chen and Lee, 2003). This estimate can be made based on hydrographs, using a variety of manual (Barnes, 1939) or automated methods (Eckhardt, 2005). The hydrograph can be separated into four phases over time: (i) ascension or growth curve, which corresponds to the increase in flow that occurs as a result of precipitation, (ii) the peak region of the hydrograph, where the maximum flow occurs, (iii) decreasing curve, corresponding to the progressive decrease of the direct surface runoff until it vanishes and (iv) recession or depletion curve, which corresponds only to base flow contribution.
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Monitoring ice break-up on the Mackenzie River using MODIS data

Monitoring ice break-up on the Mackenzie River using MODIS data

constriction were found to be important factors controlling ice runs and ice break-up. MODIS is currently the most promising tool for frequent monitoring of river ice pro- cesses as ground-based stations along the Mackenzie River are continuously being closed. Operating aboard two satellites (Aqua and Terra), the MODIS sensor allows for multiple daily acquisitions simultaneously along extensive stretches of the MR. Fur-

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A method to assess instream water quality – the role of nitrogen entries in a North German rural lowland catchment

A method to assess instream water quality – the role of nitrogen entries in a North German rural lowland catchment

Since December 2000, the integrated protection of all wa- ter bodies has been legally regulated for all European Union member states by the European Water Framework Directive (EC, 2000). Many rivers still do not reach a good status, which is aimed at for the year 2015. Concerning the chemical water quality the sources of poor quality and their pathways have to be detected. Tributaries can have a substantial influ- ence on the nutrient balance of surface water bodies. Some tributaries can differ considerably from the main stream re- garding the analysed parameters. According to Johnes and Burt (1993), obvious changes of nutrient concentrations and loads can occur downstream of tributaries and point sources. Lowland areas are characterised by a flat topography, low hydraulic gradients and near-surface groundwater. Drainage systems like tile drainage and open ditches change the natural water balance and influence the instream water quality due to a faster nutrient transport. Hooda et al. (1997) examined six small streams in agricultural catchment areas in Scotland and found that field drains or smaller ditches, despite having rela- tively high NO 3 -N concentrations, contributed small overall
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COMPARATIVE STUDY OF THE ZOOPLANKTON COMPOSITION OF SIX LACUSTRINE ECOSYSTEMS IN CENTRAL BRAZIL DURING THE DRY SEASON

COMPARATIVE STUDY OF THE ZOOPLANKTON COMPOSITION OF SIX LACUSTRINE ECOSYSTEMS IN CENTRAL BRAZIL DURING THE DRY SEASON

belonging to the Rotifera, 17 to Cladocera and 10 to Copepoda. The highest number of species was obtained in the sample from Bonita Pond (32 species) and the lower number was found in the waste stabilization ponds (7 species). Paranoá Reservoir (19 species), Descoberto Reservoir (18 species) Formosa Pond (18 species) and Santa Maria Reservoir (14 species) represented an intermediate situation between these two extremes. As can be seen in Table 1, there is also an obvious gradient of water quality conditions among the studied ecosystems, from the oligotrophic Bonita Pond to the hypertrophic Sewage Ponds. From this general picture it is possible to observe a tendency of decreasing diversity with increasing trophic level. Such relationship is well documented in literature and is related to the extreme restrictive environmental conditions associated with the eutrophication process (Sladecék, 1983). However, it should be kept in mind that the results from Bonita Pond and, in a lesser extend from Formosa Pond, are influenced by the records of typical littoral species. Differences in sampling methods applied in the ecosystems are believed not to have any implications in qualitative studies such as the present one.
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São Francisco river basin

São Francisco river basin

Variations in chromosome number and morphology can be found between distinct groups of organisms or dif- ferent populations of the same species, as well as among different individuals of the same population and even be- tween different cells of the same specimen. Although intra-individual chromosome variation is not a common feature, there are some reports describing its occurrence in fishes. Indeed, different somatic cells of the salmonid Oncorhynchus mykiss ( = Salmo irideus) can show a varia- tion in diploid number from 2n = 58 to 2n = 65 with a main- tenance of the fundamental number (i.e. the number of chromosome arms) equal to 104, characterizing a Rober- tsonian polymorphism (Ohno et al.,1965). Similar data have also been reported by Beçak et al. (1966) for Lepomis cyanellus, where three karyotypes were detected within the population: (1) a homozygote form with 2n = 48 acro- centric chromosomes, corresponding to the standard karyo- type for this species; (2) a homozygote form with 2n = 46 chromosomes (44 acrocentrics + 2 metacentrics); and (3) a heterozygote form with 2n = 47 chromosomes (46 acro- centrics + 1 metacentric). It was concluded that this varia- tion was due to centric fusions between acrocentric chro-
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Baseflow simulation using SWAT model in an inland river basin in Tianshan Mountains, Northwest China

Baseflow simulation using SWAT model in an inland river basin in Tianshan Mountains, Northwest China

Abstract. Baseflow is an important component in hydrolog- ical modeling. The complex streamflow recession process complicates the baseflow simulation. In order to simulate the snow and/or glacier melt dominated streamflow reced- ing quickly during the high-flow period but very slowly dur- ing the low-flow period in rivers in arid and cold northwest China, the current one-reservoir baseflow approach in SWAT (Soil Water Assessment Tool) model was extended by adding a slow- reacting reservoir and applying it to the Manas River basin in the Tianshan Mountains. Meanwhile, a digital filter program was employed to separate baseflow from stream- flow records for comparisons. Results indicated that the two- reservoir method yielded much better results than the one- reservoir one in reproducing streamflow processes, and the low-flow estimation was improved markedly. Nash-Sutcliff efficiency values at the calibration and validation stages are 0.68 and 0.62 for the one-reservoir case, and 0.76 and 0.69 for the two-reservoir case. The filter-based method estimated the baseflow index as 0.60, while the model-based as 0.45. The filter-based baseflow responded almost immediately to surface runoff occurrence at onset of rising limb, while the model-based responded with a delay. In consideration of wa- tershed surface storage retention and soil freezing/thawing effects on infiltration and recharge during initial snowmelt season, a delay response is considered to be more reasonable. However, a more detailed description of freezing/thawing processes should be included in soil modules so as to deter- mine recharge to aquifer during these processes, and thus an accurate onset point of rising limb of the simulated baseflow.
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Allozyme comparison of two populations of Rineloricaria (Siluriformes,

Allozyme comparison of two populations of Rineloricaria (Siluriformes,

Voucher specimens were deposited in the ichthyolo- gical collection of the Núcleo de Pesquisas em Limnologia, Ictiologia e Aquicultura, Universidade Estadual de Marin- gá (NUP): Rineloricaria pentamaculata: NUP 2599, from the Keller River and R. aff. pentamaculata: NUP 4292, from the São João River. Twelve enzymatic systems (AAT, ADH, EST, GCDH, G3PDH, GPI, IDH, LDH, MDH, ME, PGM and SOD) were analyzed, which allowed to score 22 loci. Table 1 shows the analyzed enzymatic systems and the respective allele frequencies. In the sample from the Keller River, only Aat-2, Est-3 and Mdh-C (13.64% of all loci) showed allele variation, with four, three and two alleles, re- spectively. In the sample from the São João River, only Aat-2 and Est-3 (9.09% of all loci) presented variation, with three alleles each.
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Utopia: in search of a definition

Utopia: in search of a definition

Utopia should not fail to ponder the reproduction of life. This consists of thinking substantively about how to replenish the material base of life; a key task in a world based on consumerism. It is clear, however, that reflection is not required in order to maintain consumerism. In the utopia of the twenty-first century, we must aim to build another world using natural heritage intelligently without casting aside the work of the millions of people who have helped to shape current spaces or, that is to say, produced space. This consists of seeking to ensure dignified living conditions for the planet’s human and nonhuman population; a task that has yet to be completed. It consists of seeking lifestyles that ensure food security, shelter, and full socialization for all people. It consists of lend- ing a new meaning to existence that goes beyond achievement through consumption.
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Estimation of flow components by recursive filters: case study of Paracatu River Basin (SF-7), Brazil

Estimation of flow components by recursive filters: case study of Paracatu River Basin (SF-7), Brazil

Specific mapping of the groundwater discharge by sepa- ration of its hydrograph components, in nested basins, can be a useful diagnostic tool for articulating issues involv- ing environmental policies and water resources, with the objective of developing a sustainable management frame- work. This applies to the geo-environmental management context in which government intends to gradually imple- ment management policies, such as water tax and payment for environmental services. Mapping makes it possible to recognize the relative importance of each basin sub-region regarding the underground water supplied to the rivers. With this information, water and soil conservation man- agements can be valued, mainly in the most critical areas. Thus, one of the adapted policies could be that whoever best contributes to the recharge maintenance of the aquifer would pay less for water usage, or maybe, as a counterpart, would be paid for the environmental service provided. Since most water resource conflicts occur during dry seasons, when river flow is sustained mainly by groundwater dis- charge, the base flow (and its respective mapping) quantifies the most critical characteristics to be considered. In addi- tion, quick flow mapping could indicate areas that are inter- esting for the implementation of flow retention and regular- ization techniques, which involve water containment during the rainy season and its liberation during the dry season.
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A description of mercury in fishes from the Madeira River Basin, Amazon, Brazil

A description of mercury in fishes from the Madeira River Basin, Amazon, Brazil

Data presented here were collected in each area over the past 14 years by different groups, in several surveys carried out in both dry (May – October) and rainy seasons (December – March). All of the samples were transported in iceboxes to the Rondonia Federal University (UNIR) where they were catalogued and stored in freezers until analysis. Total mercury was extracted according to Bastos et al. (1998). Briefly, about 500 mg of fish were digested in a microwave oven or a water bath (35 min) using H 2 O 2 , H 2 SO 4 :HN0 3 (1:1) and KMnO 4 5%, with total Hg determinations by cold vapor atomic absorption spectrophotometer (CV-AAS, Flow Injection Mercury System-FIMS-400 Perkin-Elmer, Germany). All samples were done in triplicate and analyzed in parallel with internationally certified material (DORM-2, NRC-Canada) as well as standard samples (APPX-2958, APPX-2960 e AFPX- 5130) produced in our own laboratory.
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The fish fauna of the Jacaré-Guaçu River basin, Upper Paraná River basin

The fish fauna of the Jacaré-Guaçu River basin, Upper Paraná River basin

The Jacaré-Guaçu River, focus of this study, is one of the main tributaries of the right margin of the Tietê River, one of the largest tributaries of the Upper Paraná River Basin. The Upper Paraná River comprises all the Paraná River drainage upstream the Salto de Sete Quedas, a natural geographic barrier submerged by the formation of the Itaipu reservoir in 1982 (Agostinho & Julio Jr. 2002). Denominated as a natural ichthyofaunistic province (Géry 1969), this basin has been considered by many authors as a region with elevated endemism rate (Vari 1988, Langeani 1989, Castro et al. 2003). The estimated ichthyofauna of the Upper Paraná River basin is 310 species, distributed in 38 families and 11 orders (Langeani et al. 2007). The Siluriformes and Characiformes are the richest orders, comprising the majority of the dominant groups in the lotic environments. Despite the high importance and representativeness of the Upper Paraná River basin for the Neotropical fish diversity, a depletion of its fish fauna has been progressing in the last two decades (Agostinho et al. 2007). Several factors may be responsible for this event: the presence of a high number of dams; introductions of alien species; overfishing; and the drainage of large urban and agricultural areas (Agostinho & Julio Jr. 1999).
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