Evaluation of Hydrological Alterations at the Sub-Daily Scale Caused by a Small Hydroelectric Facility

This work aims to evaluate the hydrologic changes caused by a small hydropower plant on the watercourse in which it is installed. Since hydrologic research with data of temporal frequencies less than a day is less common than daily measurements, there are few indicators and methodologies capable of treating such records. For this reason, 17 indicators are proposed which describe the magnitude, duration, frequency and rate of changes in hydrologic conditions occurring in a watercourse at a sub-daily frequency. These 17 indicators were used to assess changes in the flow regimes at sub-daily scales across the Itiquira hydroelectric facility in Mato Grosso, Brazil. During the dry season the river was more susceptible to hydroelectric operations than during the wet season. Eighty-eight percent of the proposed indicators were significantly altered during the dry season compared to 71% during the rainy season. In addition to the number of indicators that changed between the seasons, the magnitude of the change was different. During the dry season, 53% of the magnitudes of the proposed indicators were classified as having a high magnitude of change, while in the rainy season only 6% of the indicators were characterized as having a high magnitude of change.

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First occurrence of Quadrigyrus nickoli (Acanthocephala) in the ornamental fishHyphessobrycon eques

Revista Brasileira de Parasitologia Veterinária ◽

10.1590/s1984-29612013000100020 ◽

2013 ◽

Vol 22 (1) ◽

pp. 110-113 ◽

Cited By ~ 5

Author(s):

Rodrigo Yudi Fujimoto ◽

Edilene Santos Almeida ◽

Daniel Guerreiro Diniz ◽

Jorge Costa Eiras ◽

Mauricio Laterça Martins

Keyword(s):

Rainy Season ◽

Paratenic Host ◽

Dry Season ◽

Amazon Region ◽

Seasonal Occurrence ◽

Mato Grosso ◽

First Occurrence

The objective of this work was to report the first seasonal occurrence of the acanthocephalan Quadrigyrus nickoliSchmidt & Hugghins, 1973(Quadrigyridae), in the “Mato Grosso”Hyphessobrycon eques (Characidae) (Steindachner, 1882), collected from the Chumucuí River, state of Pará, Brazil. The fish were collected between July 2006 (rainy season) and June 2007 (dry season) and were examined for parasites using pattern techniques. A total of 75 parasites were found in the stomach and intestine. Among 83 fish examined (50 in the dry season and 33 in the rainy season), 22 were parasitized by cystacanths of Q. nickoli. The importance of H. eques as a paratenic host for Q. nickoli is discussed. This is the first study on the biology of and infection by Q. nickoli occurring in the eastern Amazon region.

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Diurnal, Seasonal and Annual Variation of Microwave Radio Refractivity Gradient over Akure, South West Nigeria

Physical Science International Journal ◽

10.9734/psij/2019/v23i430161 ◽

2019 ◽

pp. 1-11

Author(s):

Adekunle Titus Adediji ◽

Joseph Babatunde Dada ◽

Moses Oludare Ajewole

Keyword(s):

Rainy Season ◽

Annual Variation ◽

Ground Surface ◽

Local Effect ◽

Dry Season ◽

Radio Link ◽

Wet Season ◽

Annual Variations ◽

Microwave Radio

In this study, four years in-situ measurements of atmospheric parameters (pressure, temperature and relative humidity) were carried out. The measurement was by placing an automatic weather station at five different heights: ground surface, 50, 100, 150 and 200 m respectively on a 220 m Nigeria Television Authority TV tower in Akure, South Western Nigeria. The four years Data collected (January 2007 to December 2009 and January to December 2011) were used to compute radio refractivity and its gradient. The local effect of a location/ region cannot but looked into when designing effective radio link, hence the diurnal, seasonal and annual variations of the radio refractivity gradient were studied. Results showed that refractivity gradient steadily increases inthe hour of 8:30 and 9:30 to 18:00 during dry season throughout the years investigated, and decreases two hours in the rainy season than the dry season. The record shows that at 50 m altitude, the maximum and minimum values are 158 N-unit/km around 14:30 and - 286 N-unit/km around 13:30 to 14:00 hrs, LT during the dry and rainy season respectively. Seasonally, refractivity gradient is steeper with greater variability in the dry season months than in the wet season months.

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Zooplankton community structure of two marginal lakes of the River Cuiabá (Mato Grosso, Brazil) with analysis of Rotifera and Cladocera diversity

Brazilian Journal of Biology ◽

10.1590/s1519-69842003000200018 ◽

2003 ◽

Vol 63 (2) ◽

pp. 329-343 ◽

Cited By ~ 46

Author(s):

I. F. Neves ◽

O. Rocha ◽

K. F. Roche ◽

A.A. Pinto

Keyword(s):

Rainy Season ◽

Zooplankton Community ◽

Taxonomic Composition ◽

Domestic Sewage ◽

Dry Season ◽

Zooplankton Community Structure ◽

Keratella Cochlearis ◽

Mato Grosso ◽

Littoral Region ◽

Mato Grosso Do Sul

In the present study, two small lakes on the margins of the River Cuiabá were analyzed regarding taxonomic composition and population densities of the zooplankton. Diversity was evaluated for two groups, Rotifera and Cladocera; sampling was carried out on two dates: 2 March 1999, in the rainy season, and 25 August 1999, in the dry season. Seventy-nine rotifer taxa, 30 cladoceran taxa, and 6 copepod taxa were found. Comparing the species identified in the present study with those recorded by other authors for several water bodies in Mato Grosso and Mato Grosso do Sul states, it was found that 9 species of Cladocera, 2 of Copepoda, and 14 of Rotifera are new records for the region. The most abundant rotifer species were Keratella cochlearis, Brachionus angularis, Polyarthra vulgaris, and Keratella americana. Moina minuta and Bosminopsis deitersi were dominant among the cladocerans, and Notodiaptomus transitans and N. devoyorum among the copepods. Comparing both lakes, the greatest species richness of both Rotifera and Cladocera was observed in Lake Souza Lima, during the rainy season. This is probably linked to the fact that the littoral region of this lake is densely colonized by macrophytes. The lake also has better environmental conditions since it does not receive domestic sewage inputs, as does Lake Parque Atalaia. The diversity of the Rotifera was markedly low in Lake Parque Atalaia, during the dry season, again perhaps linked domestic sewage input found in this water body.

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Spatial and temporal variability of canopy cover and understory light in a Cerrado of Southern Brazil

Brazilian Journal of Biology ◽

10.1590/s1519-69842010000100005 ◽

2010 ◽

Vol 70 (1) ◽

pp. 19-24 ◽

Cited By ~ 12

Author(s):

JP. Lemos-Filho ◽

CFA. Barros ◽

GPM. Dantas ◽

LG. Dias ◽

RS. Mendes

Keyword(s):

Rainy Season ◽

Light Availability ◽

Canopy Cover ◽

Dry Season ◽

Photon Flux ◽

Photon Flux Density ◽

Spatial And Temporal Variability ◽

Wet Season ◽

Area Index ◽

Understory Plants

Canopy cover has significant effects on the understory environment, including upon light availability for seedling growth. The aim of the present study was to verify spatial heterogeneity and seasonal changes in the canopy cover of a dense Cerrado area, and their relationship to understory photosynthetic active radiation availability. Leaf area index (LAI) values in the rainy season varied from 0.9 to 4.83, with 40% of the values ranging from 4.0 to 5.0, while in the dry season LAI varied from 0.74 to 3.3, with 53% of the values oscilating from 2.0 to 3.0. Understory light (Qi ) and the Lambert-Beer ratio (Qi/Qo) were taken around noon on sunny days (between 11:00 AM and 1:00 PM). They were also statistically different (p < 0.01) between the dry and wet seasons, with 72% of sampled points in the rainy season presenting photosynthetic photon flux density (PPFD) values lower than 250 μmol.m-2/s around noon, whereas in the dry season, most PPFD values varied from 1500 to 1817 μmol.m-2/s , thus providing high light availability for understory plants. In most of the studied sites, understory plants did not even receive enough light for 50% of their photosynthetic capacity in the wet season. In contrast during the dry season, Qi/Qo values of 0.8 to 1.0 were observed in more than 50% of the points, thereby allowing for photosynthetic light saturation. Thus, light variability around noon was higher during the dry season than in the wet season, its heterogeneity being related to spatial complexity in the canopy cover.

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Hydrogeological, hydrochemical, and natural isotopes evaluation of groundwater and surface water interactions in the alluvial plain, tropical region of southeastern Brazil

10.22541/au.163534840.02185492/v1 ◽

2021 ◽

Author(s):

Waldilene Correa ◽

Sueli Pereira ◽

Joaquim Ernesto Bernardes ◽

Paulo Ricardo Pereira

Keyword(s):

Surface Water ◽

Groundwater Flow ◽

Rainy Season ◽

Dry Season ◽

Alluvial Plain ◽

Morphological Features ◽

Southeastern Brazil ◽

Wet Season ◽

Natural Isotopes ◽

Abandoned Meanders

Groundwater-Surface water interactions in alluvial plains facing morphological features are the subject of the study. Considered transitions zones, alluvial plains have different morphological features interfering with groundwater flow and hydrochemistry. The alluvial plain of Mogi Guaçu river (southeastern Brazil) presented topography-controlled groundwater flow, nevertheless, natural levees, wet fields, oxbow lakes, and abandoned meanders can control local flow and interfere in discharges points of the main river. Two sampling water campaigns were done in the dry and wet season for physicochemical and natural isotopes analysis, collecting in total 44 groundwaters samples from monitoring wells and eight water samples from the river, creek, and lake. The groundwaters in wet fields and terraces, and surface waters from creek and lake presented low mineralization (EC from 8 to 37 μS.cm), pH acidic (4.98 to 5.8), and essentially Ca and Na-HCO composition. River waters samples presented pH between 5.92 e 7.69 (acidic in the rainy season and basic in the dry season), and EC from 24.2 and 181.1 μS/cm (lower values in the wet season), Na-HCO and Na-HCO-SO (dry season) and Ca-HCO and Na-HCO (rainy season) compositions. In dry season groundwaters composition showed evolution from sodium mixed (SO – HCO) to bicarbonate waters and higher mineralization; in wet season waters varied from Ca to Na-HCO composition and low mineralization, denoting dilution due to rainwater infiltration. Closer to the river margins, in abandoned meanders and oxbows, the groundwaters have increased values of EC and major ions indicating GW-SW mixtures, and effluent-influent changes (descendent and ascendent flux) in wet and dry seasons, respectively. Natural isotopes in groundwaters imply meteoric origin, without evaporation during recharge and high d-excess can be influenced by continental air masses and Amazonia Basin low-level jet. Shallow water table, permeable silty-sand material of vadose zone, flat terrain, and pristine conditions can contribute to direct infiltration of rainwaters, recharging the shallow aquifer.

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Wetland dynamics at the transition between humid and semiarid environments of inland Brazil: São Francisco river morphodynamics and implications for the Pandeiros wetland.

10.5194/egusphere-egu21-9075 ◽

2021 ◽

Author(s):

Diego Alves de Oliveira ◽

Cristina Helena Ribeiro Rocha Augustin ◽

Trevor Hoey ◽

Cristina Persano

Keyword(s):

Hydrological Regime ◽

Dry Season ◽

Oxbow Lakes ◽

Wet Season ◽

Buffer Zones ◽

Mato Grosso ◽

Base Level ◽

Level Data ◽

Annual Range ◽

Flood Pulses

The presence of wetlands as a result of local fluvial and hydrological conditions constitutes a frequently observed feature of such rivers. Therefore, they are important elements of the basin, because besides functioning as buffer zones for CO2 and sediments they also house important ecosystems, playing an important role in the control of water circulation.&#160;Brazilian wetlands have different typologies and sizes, varying from huge swamplands such as the Pantanal do Mato Grosso, to flooded savannas called &#8220;veredas&#8221; or oxbow lakes. Their distribution in inland areas depends on the variety of flood pulses mainly linked to seasonality with the presence of distinct dry and wet seasons (Junk et al., 1989).&#160;This strong seasonality affects the S&#227;o Francisco River (SFR), the 4th largest river in Brazil, which has frequent marginal lakes and swamps as it passes through five Brazilian states. This research aims to analyze the effect of the variation of the SFR level from 1925 to 2018, on the flow of the Pandeiros River which is one of many tributaries on the left side of SFR and on its wetland (&#8220;Pantanal Mineiro&#8221;). This wetland is hydrogeomorphologically linked to the SFR and receives water inputs during SFR flood periods.&#160;Measurements of the SFR water level performed once daily in the morning were obtained from gauging station no 44200000 belonging to the Companhia de Pesquisa de Recursos Minerais (CPRM) [altitude 445 m; 15&#176;56'57.84"S; 44&#176;52'4.68"W. The hydrological year starts at the end of the dry season on October 1st. Time series analyses (level duration curve, Seasonal Trend Decomposition (STL) of the daily level data, monthly level, mean, maximum, minimum level for each day of the year) were conducted to describe the hydrological regime and to assess temporal changes of the SFR levels and how these affect the magnitude, frequency and duration of flooding of the Pandeiros&#8217;s River wetland.&#160;Field observations (March 14, 2018) show that when SFR, which is Pandeiro&#8217;s base level, reaches a level of 5.0 m this leads to flooding conditions of the Pandeiros River wetland.&#160;Over the full period of record (1925-2018) the average level of the SFR was 3.86 m, with a minimum annual average of 2.43 m during the dry season (winter) and maximum of 5.98 m during the wet season (summer), with an average annual range of 3.55 m between both seasons. The SFR was above the 5.0 m threshold flooding level for 20% of the time 1925-2018, which corresponds to an average of 77.8 days of flooding per year in the wetland. The longest period of inundation was 178 days in 1926, when the SFR reached its maximum recorded level, and the shortest was 1 day in 2015, when it reached its minimum. The number of days per year of inundation have decreased over the full record, but that this is mainly due to a significant decrease since 1985. Prior to this, cyclic differences between wetter (1925 and 1985) and drier periods (1925 to 1945, 1945 to 1965) are observed.

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Avian Communities of a Mixed Mopane-Acacia Savanna in the Cuvelai Drainage System, North-Central Namibia, During the Dry and Wet Season

Vestnik Zoologii ◽

10.2478/vzoo-2014-0040 ◽

2014 ◽

Vol 48 (4) ◽

pp. 333-338 ◽

Cited By ~ 1

Author(s):

G. Kopij

Keyword(s):

Rainy Season ◽

Diversity Index ◽

Drainage System ◽

Dry Season ◽

Line Transect ◽

Wet Season ◽

North Central ◽

Numida Meleagris ◽

Dominance Structure ◽

Shannon’S Diversity Index

Abstract Studies were conducted by means of the Line Transect Method in late rainy season (March), in the middle of dry season (July) and at beginning of rainy season (November).Th e total length of all transects was c. 11 km. In total, 70 resident and 13 nonresidentspecies were recorded. Th e number of species in dry season was significantly lower than in rainy season (x2-test: 14.1; p < 0.01). Th e highly significant seasonal differences in abundance were recorded for the following species: Streptopelia senegalensis, Streptopelia capicola, Uraeginthus angolensis, Cisticola juncidis, Upupa africana, Cynniris mariquensis, and Numida meleagris. In overall, five species have been classified as dominants: Streptopelia senegalensis, Streptopelia capicola, Uraeginthus angolensis, Plocepasser mahali and Cypsiurus parvus. They comprised together 43.9 %. Significant variations in the dominance structure between the wet and dry season have been evidenced. Granivores were much more numerous in the dry than in the wet season, while for the insectivores the reverse was true. Although Sorensen Coefficient was much the same between all three seasons, the Shannon’s Diversity Index was lower in July than in March and November.

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Seasonal variation in the leaf gas exchange of tropical forest trees in the rain forest–savanna transition of the southern Amazon Basin

Journal of Tropical Ecology ◽

10.1017/s0266467405002427 ◽

2005 ◽

Vol 21 (4) ◽

pp. 451-460 ◽

Cited By ~ 29

Author(s):

Eduardo Jacusiel Miranda ◽

George L. Vourlitis ◽

Nicolau Priante Filho ◽

Pedro Correto Priante ◽

José Holanda Campelo ◽

...

Keyword(s):

Rain Forest ◽

Amazon Basin ◽

Deciduous Forest ◽

Leaf Gas Exchange ◽

Light Response ◽

Dry Season ◽

Forest Trees ◽

Wet Season ◽

Mato Grosso ◽

Physiological Capacity

The photosynthetic light response of Amazonian semi-deciduous forest trees of the rain forest–savanna transition near Sinop Mato Grosso, Brazil was measured between July 2000 and September 2003 to test the hypothesis that the photosynthetic capacity of trees acclimated to different growth light environments will decline during the dry season. Maximum photosynthesis (Amax) and stomatal conductance (gmax) were significantly higher during the wet season; however, the physiological response to drought was not a clear function of growth light environment. For some species, such as Psychotria sp. growing in the mid-canopy, internal leaf CO2 concentration (Ci) was >30% lower during the dry season suggesting that declines in Amax were caused in part by stomatal limitations to CO2 diffusion. For other species, such as Brosimum lactescens growing at the top of the canopy, Tovomita schomburgkii growing in the mid-canopy, and Dinizia excelsa growing in the understorey, dry season Ci declined by <20% suggesting that factors independent of CO2 diffusion were more important in limiting Amax. Dry-season declines in gmax appeared to be important for maintaining a more consistent leaf water potential for some species (T. schomburgkii and D. excelsa) but not others (Psychotria sp.). These results indicate that while seasonal drought exerts an important limitation on the physiological capacity of semi-deciduous Amazonian forest trees, the mechanism of this limitation may differ between species.

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PREDIKSI DEBIT ALIRAN MASUK KE TELAGA MENJER MENGGUNAKAN PERSAMAAN NERACA AIR DAN PEMODELAN HEC-HMS

Jurnal Teknik Hidraulik ◽

10.32679/jth.v12i2.655 ◽

2021 ◽

Vol 12 (2) ◽

pp. 119-130

Author(s):

Hiro Agung Pratama ◽

Jazaul Ikhsan ◽

Apip Apip

Keyword(s):

Water Balance ◽

Rainy Season ◽

Catchment Area ◽

River Flow ◽

Hydroelectric Power Plant ◽

Dry Season ◽

Hydropower Plant ◽

Hydroelectric Power ◽

Flow Monitoring ◽

Inflow Prediction

The Menjer lake is the main source for Hydroelectric Power Plant of the PLTA Garung. Information about the water balance and the potential of existing water resources in the Menjer Catchment Area (DTA) is needed to obtain an efficient operating pattern, the sustainability of the Garung hydropower plant, and good management of the Menjer Lake. The purpose of this study was to estimate the inflow of three main rivers in the Menjer catchment area using HEC-HMS hydrological and water balance approach. Simulated results of the HEC-HMS model shows that the average of total the inflows of three main rivers to the Menjer lake in 2017, 2018 and 2019 during rainy season are 0.954 m3/s, 0.944 m3/s, and 1.017 m3/s, and during dry season are 0.820 m3/s, 0.783 m3/s, and 0.80 m3/s, respectively. While the prediction results of the discharge with the equation of the water balance shows that the average of total river inflows to the Menjer lake during rainy season is 2017 is 1.628 m3/s, in 2018 it is 1.579 m3/s, and in 2019 it is 3.296 m3/s and during dry season is 1.893 m3/s in 2017, 1.176 m3/s tahun 2018, and 1.893 m3/s in 2019. These results indicate that the results of discharge modeling with HEC-HMS are smaller than those predicted by the water balance equation. The study concluded that HEC-HMS could be used to predict daily inflows. However, further calibration and validation need to be carried out by recommending installing a river flow monitoring station at each river outlet.Keywords: water balance HEC-HMS, inflow prediction

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Dry season and soil texture affect the chemical control of monocotyledonous in sugarcane

Comunicata Scientiae ◽

10.14295/cs.v8i3.1594 ◽

2018 ◽

Vol 8 (3) ◽

pp. 477-485

Author(s):

Hudson Kagueyama Takano ◽

Denis Fernando Biffe ◽

Jamil Constantin ◽

Rubem Silvério de Oliveira Junior ◽

Guilherme Braga Pereira Braz ◽

...

Keyword(s):

Soil Texture ◽

Rainy Season ◽

Clayey Soil ◽

Dry Season ◽

Weed Species ◽

Wet Season ◽

Sugarcane Crop ◽

Dry Conditions ◽

Loam Soil ◽

Great Complexity

The chemical weed control in sugarcane during the wet season is more effective than the control carried out during the dry season. The objective of this study was to evaluate the efficacy of herbicides in the rainy season and in the dry season in sugarcane crop, and in different soil textural classes. The experiments simulated dry season and rainy season basing on periods of days in which experiment was submitted to irrigation restriction. In each experiment, it was tested 50 and 100% of the dose of the main herbicides commonly used in sugarcane to control B. decumbens, B. plantaginea, P. maximum and D. horizontalis. In general, in dry conditions, as well as varying the soil texture, there are restrictions in the choice of herbicide to be used due to the reduced effectiveness of some treatments in certain situations. In the very-clayey soil, especially in the dry season, the efficacy of herbicides is better, whereas, for the sandy-clay-loam soil in dry conditions, the effectiveness of herbicides is restricted. Thus, this study, despite the great complexity of the variables to be analyzed, permitted to establish guidelines for decision making on the most appropriate herbicide to be applied in each studied condition, in order to control these weed species.

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