Groundwater-induced Seasonal Slumps in Gullies of the Bação Complex, Southeastern Brazil

2021 ◽  
Author(s):  
Yesser Marin Rodriguez Hernandez ◽  
Luis de Almeida Prado BACELLAR ◽  
Jefferson Alves Araujo Junior
Keyword(s):  
Rainy Season ◽  
Large Scale ◽  
Agricultural Land ◽  
Unsaturated Flow ◽  
Low Cost ◽  
Limit Equilibrium ◽  
Mass Movement ◽  
Dry Season ◽  
Southeastern Brazil ◽  
Mass Movements

Abstract Areas with a high density of large-scale gullies are frequent in regions of the crystalline basement of southeastern Brazil, such as the Bação Complex. These gullies pose a high risk for people and properties, and cause loss of agricultural land, silting up and flow reduction of waterways, among other impacts. Gullies originating as erosion by channelized surface runoff can be controlled relatively easily by ordinary containment practices. However, when erosive channels reach the groundwater, erosive processes conditioned by subsurface flows start acting, causing mass movements and their control becomes more difficult. Continuous field monitoring shows that these mass movements occur not only in the rainy season, as expected, but also in the dry season. To understand the dynamics of mass movement in the evolution of these features, a representative unstable gully in the Bação Complex was selected. As it is common in this region, this gully presents very steep and unstable slopes, especially due to slumps. Numerical simulations of saturated and unsaturated flow have shown that, in this region of high seasonality, the aquifer is recharged in two stages. Safety factor analysis by limit-equilibrium method indicates that slumps occur during the rainy season, when the aquifer at the toe of the slope is recharged, and in the dry season, when the upper slope is recharged after a few months' lags due to thicker unsaturated zone having slower water flow. Finally, a low-cost stabilization method was proposed involving the construction of alternative drains and retention walls.

scholarly journals Seasonal and spatial variability of antibiotic resistance genes and Class I integrons in the rivers of the Mekong delta, Vietnam

2021 ◽  
Author(s):  
Thi Thu Hang Pham ◽  
Khoa Dinh Hoang Dang ◽  
Emmanuelle Rohrbach ◽  
Florian Breider ◽  
Pierre Rossi
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Rainy Season ◽  
Large Scale ◽  
River Sediments ◽  
Mekong Delta ◽  
Antibiotic Resistance Genes ◽  
Dry Season ◽  
Class I ◽  
Economic Losses

Aquaculture activities are steadily expanding in Vietnam, covering an estimated 700,000 ha, with 89% of these culture ponds located in the Mekong Delta. Since 2009, large-scale bacterial epidemics have spread in response to this intensive cultivation. Antibiotics, even those considered as a last resort, have only partially mitigated this problem. In turn, the side effects of the massive use of these chemicals include the appearance of mobile genetic elements associated with antibiotic resistance genes (ARGs). The large-scale emergence of a diverse bacterial resistome, along with severe economic losses, has posed significant health risks to local residents. In this study, the seasonal and spatial distributions of the class I integrase (CL1) intl1 and the ARGs sul2 (sulfonamide), BLA-oxa1 (β-lactams), and ermB (erythromycin) were quantified from water and sediment samples collected during two consecutive seasons along the Vam Co River and its tributary (Long An province, Vietnam). The results showed that CL1 was present in all river compartments, reaching 2.98×104 copies/mL and 1.07×106 copies/g of sediment, respectively. The highest relative copy abundances to the 16S rDNA gene were measured in water samples, with up to 3.02% for BLA-oxa1, followed by sul2 (1.16%) and ermB (0.46%). Strong seasonal (dry season vs. rainy season) and spatial patterns were recorded for all resistance genes. Higher amounts of ARGs in river water could be associated with higher antibiotic use during the rainy season. In contrast, higher amounts of ARGs were recorded in river sediments during the dry season, making this habitat a potential reservoir of transient genes. Finally, the observations made in this study allowed us to clarify the environmental and anthropogenic influences that may favor the dispersal and persistence of ARGS in this riverine ecosystem.

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

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.

scholarly journals The Corrosivity Level of Rawa Pening Downstream Surface Water in the Dry and Rainy Season

2020 ◽  
Vol 17 (3) ◽  
pp. 215-222
Author(s):  
Purwono Purwono ◽  
Wiharyanto Oktiawan ◽  
Titik Istirokhatun ◽  
Agus Nurfaiz
Keyword(s):  
Surface Water ◽  
Rainy Season ◽  
Agricultural Land ◽  
Ph Value ◽  
Dry Season ◽  
Hydroelectric Power ◽  
Geological Material ◽  
Measurement Results ◽  
Microbiological Parameters

Corrosion is an important factor that can affect the quality of air used by humans. This has an impact on health and economic factors, damage to air distribution equipment. The level of corrosivity of surface water as raw water for drinking water is important to be examined before the water enters the processing process or other uses such as hydroelectric power (PLTA). This study aims to measure the level of water corrosivity on the surface of the Pening swamp during the dry and rainy seasons in 2018. Taking air samples on the surface of the Pening swamp, then carrying out laboratory tests on the parameters of air corrosivity. The results showed that the downstream surface of the Pening swamp was not corrosive in terms of pH, temperature, TDS, and chloride parameters. The pH value in the dry season (J1) is 7.00, while in the rainy (J2) it is 7.77 and is non-corrosive. The temperature values are 28.6oC and 29.3oC in the rainy and dry seasons, respectively. The TDS measurement results in the dry season are lower than the rainy season by a difference of 12 mg / l. In the dry season it is 141 mg / l and the rainy season is 153 mg / l. This increase probably came from geological material (geological material) such as rocks and soil around the Pening Swamp Lake. Other sources of TDS include urban land, road workers, agricultural land and pasture. Human activities also increase in the increase of TDS in water including domestic activities (bathing and washing), trade, and industry. Chloride levels were 2.19 mg / l and 3.19 mg / l. This research has implications for the users of Sungai Pening Swamp. The corrosivity of air measurement is also by microbiological parameters which need to be investigated further.

scholarly journals PENGUSAHAAN DAN KELEMBAGAAN LAHAN PERTANIAN DI BERBAGAI AGROEKOSISTEM (KASUS DESA-DESA PATANAS)

2008 ◽  
Vol 7 (2) ◽  
pp. 19-40
Author(s):  
. Supadi
Keyword(s):  
Rural Areas ◽  
Rainy Season ◽  
Agricultural Land ◽  
Technical Problem ◽  
Growth Index ◽  
Dry Season ◽  
Production Factor ◽  
Agricultural Product ◽  
Central Java ◽  
The Status

In trying to get his land the farmer must consider the technical problem, economical and social the culture, the exploitation of agriculture always was linked with what will be produced, how many, here, when, how and where is distributed him.  The utilization of the farmer's land as the production factor that was most important in the farming really was influenced by the relations kind between humankind and his land because will be related to in continuation of his farming. The land that was made an effort to get could take the form of his property personally or property of the other person. This research was aimed at identifying and analyzing the exploitation and institutional the agricultural land in rural areas. The method used was survey that was carried out in 12 Patanas villages that were spread in Lampung, West Java, Central Java, East Java, South Sulawesi, and NTB. In three villages, 25 farm households were selected. Results of the research showed the growth index reached 200 to 300, except in the paddy-field land where its irrigation was rotated and in dryland that was cultivated with cassava. The farmer used the superior variety seed, but did not yet apply balanced fertilizing. Fertilizing exceeded the recomendation whereas for other fertilizer (P05 and K20) and relative manure utilization was still under recommendation, in fact some farmers did not use. The productivity of the crop in the rainy season (rice and corn) higher was compared to dry season, except for the potato. Generally the farmer used capital personally, “YARNEN” system was an alternative that often was followed. The price of agricultural product was fluctuating in which the price of the dry season tended to be higher than in the rainy season, the status of the farmer was dominated by owner followed by the sharecropper and the leaser. The sharecropper and the leaser always did not come from the group landless because of the owner, also entered the rented market and sharecropper. The rented system that more stressed the aspect of economics than social more prominent in production centers of the potato. Key word: farming, institutional the land, agroecosystem

scholarly journals Reproductive phenological patterns of cerrado plant species at the Pé-de-Gigante Reserve (Santa Rita do Passa Quatro, SP, Brazil): a comparison between the herbaceous and woody floras

2000 ◽  
Vol 60 (1) ◽  
pp. 129-145 ◽  
Author(s):  
M. A. BATALHA ◽  
W. MANTOVANI
Keyword(s):  
Plant Species ◽  
Rainy Season ◽  
Vascular Plant ◽  
Woody Species ◽  
Dry Season ◽  
Natural Vegetation ◽  
Reproductive Stage ◽  
Southeastern Brazil ◽  
Floristic Survey ◽  
Paulo State

A natural vegetation area, with 1269 ha, composed mainly by cerrado, located at Santa Rita do Passa Quatro Municipality, São Paulo State, southeastern Brazil (21°36-39'S, 47°36-38'W), was studied. From September 1995 to February 1997, a floristic survey was carried out, when all vascular plant species at reproductive stage were collected. The flowering and fruiting patterns of the community were studied, comparing the herbaceous and the woody species. In the herbaceous component, 239 species were found and, in the woody one, 108 species. The woody species flowered mainly at the beginning of the rainy season, while the herbaceous ones produced flowers generally at the end of that season. The proportion of anemo and autochorous species was greater in the herbaceous component. The zoochorous ones, on the contrary, were more frequent in the woody component. At the dry season, when their dispersion is more efficient, the proportion of anemo and autochorous species producing fruits was higher. During the rainy season, when their fruits become attractive for longer time, the zoochorous species fruited more intensely.

scholarly journals GEOSPATIAL MODEL FOR LARGE SCALE SEA CLIFF ROCKFALL SUSCEPTIBILITY MAPPING

2019 ◽  
Vol XLII-3/W8 ◽  
pp. 341-347
Author(s):  
P. Redweik ◽  
R. Matildes ◽  
F. Marques
Keyword(s):  
Laser Scanning ◽  
Large Scale ◽  
Mass Movement ◽  
Susceptibility Map ◽  
Mass Movements ◽  
Aerial Photogrammetry ◽  
The Status ◽  
Logistic Regression Method ◽  
Definition Of ◽  
Gis Software

<p><strong>Abstract.</strong> Due to their relevance to the environment and economy, coastal areas are considered national strategic segments that should be preserved. Since erosion phenomena occur intensively in those areas, it is capital to monitor them in order to identify risk zones. In addition to national and regional studies, it is also necessary to conduct local monitoring of erosion prone areas, especially those which are often frequented by people, such as beaches limited by high cliffs. Large scale vertical mapping is necessary to model their susceptibility to mass movements, in order to provide adequate prevention, protection and assistance.</p> <p>Recent techniques like laser scanning or aerial photogrammetry using UAVs allow the definition of the status quo of a cliff wall and its situation a few years back. But to assess the susceptibility to rock mass movements in such cliff segments, inventories of past events are of primordial importance. These inventories allow applying several statistic models to better understand susceptibility together with a set of variables of internal and external nature regarding the cliff site.</p> <p>We present a case study focused on the beach of Ribeira d’Ilhas (Mafra, Portugal), where a workflow of terrestrial photogrammetry for present day situation and recovery of old analogue stereoscopic pairs (1999, 2000, 2003) was implemented. A mass movement inventory (1999-2014) was compiled by multitemporal comparison followed by a detailed characterization of the cliff using a GIS software. Finally, the application of the logistic regression method allowed the definition of a susceptibility map of the cliff wall towards the occurrence of mass movements.</p>

scholarly journals Reproduction of species of the genus Cichla in a reservoir in Southeastern Brazil

2004 ◽  
Vol 64 (3b) ◽  
pp. 613-624 ◽  
Author(s):  
L. M. Gomiero ◽  
F. M. S. Braga
Keyword(s):  
Reproductive Behavior ◽  
Rainy Season ◽  
Dry Season ◽  
Southeastern Brazil ◽  
Gonad Maturation ◽  
Brood Care ◽  
Way Of Life ◽  
One Year ◽  
The Way

The reproduction of two species of Cichla (Cichla cf. ocellaris and C. monoculus, commonly known in Brazil as tucunaré) introduced in the Volta Grande Reservoir, southeastern Brazil, was analyzed. The period for spawning began at the end of the dry season (September) and extended until the end of the rainy season (January). The length of the first gonad maturation (L50) and the length at which all fish are considered adults (L100) were very similar for both species and coincide with the length of fish at one year of age. The analysis of disassociated oocytes evidenced a partitioned spawning, and that C. monoculus was more prolific than C. cf. ocellaris. The low fecundity, partitioned spawning, bi-parental brood care, and supplying of food for the young are related to the way of life, habitat, and reproductive behavior of these fish.

scholarly journals Diurnal and seasonal variability in bird counts in a forest fragment in southeastern Brazil

2008 ◽  
Vol 25 (2) ◽  
pp. 228-237 ◽  
Author(s):  
Alexsander Z. Antunes
Keyword(s):  
Seasonal Variation ◽  
Species Composition ◽  
Diurnal Variation ◽  
Seasonal Variability ◽  
Rainy Season ◽  
Daily Variation ◽  
Dry Season ◽  
Southeastern Brazil ◽  
Forest Fragment ◽  
Bird Census

Diurnal variation in detection can influence bird census results. I measured variation in daily and seasonal detections of birds in a forest fragment at Barreiro Rico ranch, Anhembi, state of São Paulo. Birds were recorded on transects of unlimited distance, sampled one day per month, dawn to dusk, between December 2000 and March 2001 (rainy season) and between May and August 2001 (dry season). Significant daily variation in detection occurred during the rainy season, with most detections between dawn and 9 h. In the dry season detections declined for total numbers of individuals and species and most detections occurred during late morning and mid afternoon. Detection patterns might reflect seasonal variation in bird behavior rather than seasonal variation in species composition.

Numerical modelling of toppling

1990 ◽  
Vol 27 (6) ◽  
pp. 823-834 ◽  
Author(s):  
M. A. Pritchard ◽  
K. W. Savigny
Keyword(s):  
British Columbia ◽  
Numerical Modelling ◽  
Large Scale ◽  
Distinct Element ◽  
Limit Equilibrium ◽  
Deformation Behaviour ◽  
Mass Movement ◽  
Movement Process ◽  
Flexural Toppling ◽  
Limiting Condition

Evidence of large-scale toppling deformation has been reported in association with deep-seated landslides affecting mountain slopes along the Beaver River valley, Glacier National Park, British Columbia, Canada. A study has been undertaken to quantitatively investigate the relationship between the toppling mass movement process and the deep-seated landslides; specifically, whether the landslides represent a limiting condition of the toppling process. This is the first of two papers that describe the study. Methods of toppling analysis, including limit-equilibrium, finite-element, and distinct-element methods, are critically reviewed. The distinct-element method emerges as the best technique for modelling both block and flexural modes of toppling. The method is verified by modelling three examples of toppling: a theoretical block topple, a physical model of flexural toppling, and an engineered slope from the Brenda mine near Peachland, British Columbia. The results demonstrate that the Universal Distinct Element Code (UDEC) is capable of modelling both block and flexural types of toppling, that the toppling mass movement process limits to deep-seated planar aswell as curvilinear landslides, and that other landforms such as obsequent scarps and grabens are a manifestation of the toppling process. The research reported here contributes to understanding of the deformation behaviour of engineered slopes and the evolution of natural slopes in rock masses containing pervasive discontinuities. Key words: block toppling, flexural toppling, landslide, numerical modelling, distinct element, DDEC, sackung.

scholarly journals The occurrence of amphibians in bromeliads from a Southeastern Brazilian restinga habitat, with special reference to Aparasphenodon brunoi (Anura, Hylidae)

2002 ◽  
Vol 62 (2) ◽  
pp. 263-268 ◽  
Author(s):  
R. L. TEIXEIRA ◽  
J. A. P. SCHINEIDER ◽  
G. I. ALMEIDA
Keyword(s):  
Sex Ratio ◽  
Special Reference ◽  
Threatened Species ◽  
Rainy Season ◽  
Feeding Habits ◽  
Abundant Species ◽  
Dry Season ◽  
Southeastern Brazil ◽  
Main Food ◽  
The Family

Five species of anuran amphibians, all belonging to the family Hylidae, were collected at Praia das Neves, municipality of Presidente Kennedy, southeastern Brazil,. The species were represented by four genera: Scinax, Hyla, Aparasphenodon, and Trachycephalus. Four species (A. brunoi, Hyla albomarginata, Scinax altera, and S. cuspidatus) were found during the dry season (August 1999), and two (A. brunoi and Trachycephalus nigromaculatus) in the rainy season (February 2000). Aparasphenodon brunoi was the most abundant species in Praia das Neves. Some reproductive aspects and feeding habits of this hylid were investigated. Aparasphenodon brunoi was found mainly inside the bromeliad Aechmea lingulata, the largest plant analyzed. Fifteen specimens were collected during the dry season (August 1999) (11 males and 4 females). During the rainy season (February 2000), we collected 14 specimens (3 males, 10 females, and 1 juvenile). Sex-ratio was 1:1. Frogs ranged in snout-vent length from 31.2 to 69.3 mm. Females were larger than males. One female had 1,451 fully developed oocytes in her ovaries. The major groups of prey found in the stomachs were: Insecta, Myriapoda, and Arachnida. Blattodea, Orthoptera, Lepidoptera, and Hymenoptera (only ants) were the main food types in frequency, number, and weight. Aparasphenodon brunoi is a threatened species in many habitats of southeastern Brazil. Only natural vegetation protection may guarantee its survival during the immediate future.

Sign in / Sign up

Export Citation Format

Share Document