Drainage Basin Research Articles

Landslides, bedrock incision and human-induced environmental changes in an extremely rapidly formed tropical river gorge

Landslides are hillslope processes controlled by natural changing topographic conditions. Landslides are also influenced by human activities. Yet, understanding the space-time occurrence of landslides and their interactions with these typically long-term natural and short-term human-induced controls remains a key challenge in many regions, especially in tropical environments where data scarcity is commonplace. Here we decipher these dynamic processes in the Ruzizi Gorge located in the Kivu Rift (Central Africa), that is an exceptional geomorphological landmark whose origin is associated with the rerouting of >7000 km2 of drainage area from Lake Kivu during the Holocene. This bedrock river has also seen its landscape disturbed over the past decades by the development of the city of Bukavu (DR Congo). In this study, we combine detailed field observations, historical aerial photographs, archive analysis and satellite imagery to compile a multi-temporal inventory of 385 landslides and constrain their dynamics. We show that extremely high incision rates during the early stage of the formation of the gorge explain the space-time clustering of thousand-year-old large (up to ∼2 km2) landslides, independently from the lithological context. These landslides are currently non-active and poorly eroded. Their deposit areas partly cover the riverbed with boulders, armouring the channel and inhibiting further incision. The landslides that occurred over the last 60 years are shallower slope failures of smaller size and higher mobility. They tend to disappear rather quickly from the landscape, sometimes within a few years. Their distribution is primarily controlled by threshold slopes, lithology, and the past large landslides, the influence of the land use being less pronounced. Overall, the sediment mobilization rates associated with these high frequency landslides significantly outpace the extreme landslide erosion pulse associated with the gorge formation. Our results provide insight on interactions between channel-hillslope coupling and feedbacks among landslide processes and river gorge formation in a unique environment.

Gêneros de Ephemeroptera como biodindicadores de impactos agrícolas em córregos da Mata Atlântica

ABSTRACT Insects of the Ephemeroptera order have been used as bioindicators of water quality as they respond to countless anthropic impacts. In this study, we assessed the use of Ephemeroptera as bioindicators of streams impacted by agricultural activities. We collected Ephemeroptera nymphs in six streams with different uses and soil cover in their drainage areas located in the northern region of the Brazilian state of Rio Grande do Sul. Based on soil use and cover analysis, we categorized the streams as ‘natural’ (drainage area with >42% native arboreal vegetation) and ‘agricultural’ (drainage area with >72% agricultural use). We collected a total of 2,767 organisms, distributed into four families and eleven genera. We observed greater abundance (68%) and taxonomic richness (11 genera) of Ephemeroptera in the agricultural streams. The natural streams comprise 32% of the fauna collected, with eight genera. That pattern was especially determined by the Baetidae and Leptohyphidae families. The genera Caenis, Cloeodes, and Tricorythopsis were abundant in the agricultural streams. In this study, we observed that genera of Ephemeroptera are tolerant to environmental changes, particularly those caused by agricultural activities. Therefore, the use of the order in studies to assess water quality must be carried out with caution.

Morphometric Analysis of The Alluvial Fans and Its Drainage Basins in The Sulaibiyat Depression Using Remote Sensing and GIS Techniques

Morphometric Analysis of The Alluvial Fans and Its Drainage Basins in The Sulaibiyat Depression Using Remote Sensing and GIS Techniques

О проблемах комплексного использования и охраны водных ресурсов Оренбуржья и сопредельных1 территорий

The water resources of the Orenburg region are formed mainly due to water of infiltration origin. Their dynamics and chemical composition change zonally, decreasing from north to south, from forest-steppes to dry steppes and further to the deserts of Kazakhstan in accordance to the laws of latitudinal and altitudinal zonation, which vary depending on the regions. Well hydrogeologically closed areas have a powerful zone of hydrohalogenesis. With a decrease in the closeness of the subsoil, the thickness of zones of hydrogenesis increases, reaching a maximum in the folded mountainous Urals, where hydrogeological zoning is consistent with landscape-geochemical heterogeneity and drainage basins. Concentrations of elements in waters increase from the aeration zone to the zone of normal base flow. A regional geochemical barrier of hydrogen sulfide waters for metals has been identified in the structures of the Cis-Ural region. The volume of chemical denudation decreases towards the dry steppe zone and increases in elevated areas composed of gypsum and karst rocks. To solve water management problems it is necessary to introduce modern technologies. These include complex devices with geochemical, hydrodynamic and complex barriers.

Optimizing geological design of J-shaped deviation oil & gas well by deepening kickoff point

In the geological design of 2-D J-shaped deviated oil and gas wells, once the coordinates of wellhead and production layer target are determined (restricted by specific ground conditions and underground understanding, respectively), the position of the kickoff point (KOP) becomes very sensitive. By deepening the kickoff point (KOP) based on the current conventional fixed upper position and the dog leg severity (DLS) remaining unchanged within the penetrated range, a smaller drill axis and an angle between the production layer and axis can be obtained at the same designated target point to extend the section of penetrated oil-bearing layers, expand the oil drainage area, increase proven reserves, and ultimately enhance the oil production and recovery during the contract period. In addition, after optimization, it is expected to save 1-2% of well drilling costs by reducing drilling time. With the help of drilling engineering and production engineering, drilling KOP can be achieved easily in deeper and harder rock formations, which is able to improve the efficiency of the electric submersible pump (ESP) and to avoid eccentric wear of the ESP, resulting in extension of the service life of the ESP. This optimized design also runs in parallel with various well stimulation programs and projects without any confliction of each other. This design can be either used for comparison of the parameters of the completed inclined wells with assumed ones of deepening KOP design to show how the deepening KOP can be used to differentiate the increased thickness of the penetrated target layers and the drainage area of target zones, or it can be utilized to compare any pair of parameters between inclined production wells within a range. In the same drilling field, any random increase of 1° inclination angle in a stable inclination section can lead to a corresponding increase in the thickness of the penetrated oil-bearing layer and production. Our research results quantitatively indicate that in the geological design of J-shaped deviation oil and gas wells, the KOP can be re-set from a shallower fixed position along the current conventional trajectory to a reasonable position as deep as possible, which shall be suitable for most situations of optimizing well performance, especially for some restricted complex surface conditions and energy-deficient reservoirs, which assign the KOP a new geological significance in line with the business strategy of rapid oil recovery

Holocene environmental conditions in the Eastern Sayan foothills according to a comprehensive paleoecological study of the Sosnovka mire

This research is devoted to the study of the combined vegetation dynamics, hydroclimatic conditions and fires in the foothills of the Eastern Sayan northwestern macroslope in the Holocene. The paleoecological reconstruction results obtained on the basis of AMS-dating, pollen, macrofossils, charcoal and malacofaunal analysis of peat deposits of the Sosnovka mire (right bank of the Yenisei River), covering the last ≈11,000 calendar years are presented. It was established that the process of waterlogging began at ≈9700-8500 cal yr BP at the optimum heat and moisture, when the waterless valley were covered with a mixed siberian pine-spruce-fir forest, with the maximum participation of spruce and fir. According to the study of Sosnovka mire sediments the reaction of local and regional communities to the Holocene Thermal Maximum (7500-6000 years ago) was clearly manifested. The participation of spruce and fir in the trees layer stand decreased sharply. The increase in fire activity was noted, which contributed to the lightening of forests and greater development of the shrub layer. During this interval, the process of swamping actively began in the floodplains of rivers with a drainage area in the western part of the Eastern Sayan. Based on the results of charcoal analysis six stages of increased fire activity were identified: I – about 10,000-8,800 cal yr BP, II – 7500-7200, III – 5600-5000, IV – 3700-3000, V – 2100-1800, VI – 800 cal yr BP - until now.

Predicting Streamflow Duration From Crowd‐Sourced Flow Observations

AbstractStreamflow duration is important for aquatic ecosystems and assigning stream protection status. This study predicts streamflow duration, represented as the fraction of time with flow each year, using a combination of sensor data and crowd‐sourced visual observations for a study area in northern Colorado, USA. We used 11 stream stage sensors and 177 visual monitoring points to examine how frequently streams should be sampled to compute flow fractions accurately. This showed that the number of visual observations needed to compute accurate flow fractions increases with decreasing flow duration. We then developed random forest models to predict mean annual flow fractions using climate, topographic, and land cover predictors and found that snow persistence, summer precipitation, and drainage area were important predictors. Model performance was best when using sites with ≥10 visual observations. Our model predicts that almost all (98%) of streams in the study region are non‐perennial, about 10% more than the amount of non‐perennial streams in the National Hydrography Dataset. Stream type maps are sensitive to the time period of data collection and to thresholds used to represent perennial versus non‐perennial flow. To improve maps of non‐perennial streams, we recommend moving beyond categorical classification of streams to a continuous variable like flow fraction. These efforts can be best supported with frequent observations in time that span streams with a wide range of flow fractions and drainage area attributes.

Primeiro registro do Platyfish do Sul, Xiphophorus maculatus (), (Cyprinodontiformes: Poeciliidae) em riachos costeiros da Venezuela e implicações para a conservação

Abstract Several fishes of the family Poeciliidae are commonly produced in ornamental aquaculture and also used for pest control, leading to their introduction in numerous countries. Many of these species exhibit tolerance and invasiveness, as exemplified by Xiphophorus maculatus (Günther, 1866). This report documents the presence of X. maculatus in a Caribbean coastal stream in Venezuela. Quizandal Creek has experienced significant human intervention in its lower drainage and channel area. In the final segment of the creek the fish were captured using hand nets and beach seines. The specimens were transported alive to the laboratory for evaluation and subsequently preserved according to standard methods and later were cataloged in the fish collection. 16 males ♂ and 8 females ♀ (16.6-29.4 mm SL. CPUCLA-3630) from the Quizandal Creek, part of the coastal drainage of the Borburata River, were analyzed. This is the first report on the occurrence of Xiphophorus maculatus in natural environments of Venezuela. These coastal streams are situated in a zoogeographic transition zone between regional freshwater ichthyofaunas that have a limited number of species, primarily secondary and amphidromous, which could be susceptible to the presence of introduced species. Xiphophorus fish demonstrate the ability to thrive in highly degraded environments, promoting their dispersion and amplifying the impact on the habitat and local fish, particularly small endemic fish, such as the Rivulidae and Poeciliidae.

Assessment of alterations of river flow regimes using hydro-geomorphological parameters

Climate change and anthropogenic activities can alter the streamflow regime by modifying critical elements of the flow regime. The aim of this work is to determine, by means of characteristic indices of rates of change and variability, the stage of alteration of the streamflow regime in a mountain catchment. On the basis of the daily mean streamflow, recorded over the period 1994-2020, a series of hydrological indices (Richards-Baker flashiness index, coefficient of variation, k index) were quantified, by means of which the rates of change and variability of the flow can be assessed. The results obtained show that the temporal and spatial variation of the streamflow is mainly due to natural causes, such as climatic variability and some geomorphological characteristics of the drainage basins. Thus, a clear positive correlation was observed between the Richards-Baker flashiness index and the magnitude of flood events. In the longitudinal profile, an increase in the mean values of Richards-Baker flashiness index was observed, indicating a higher variability of streamflows downstream. The higher Richards-Baker flashiness index values in the lower reaches were reflected in changes in the river channel, particularly after 2004.

Comparative analysis of hydroclimatic characteristics on the territory of the Amur, Angara-Yenisei and drainage Torey basins (Eastern Transbaikalia)

A comparative analysis of hydroclimatic characteristics was carried out on the territory of the Amur, Angara-Yenisei and Torey closed drainage basins of Eastern Transbaikalia. According to monitoring weather stations, high rates of air temperature growth have been established for the territory of the mountain-taiga zone of the Angara-Yenisei basin, where the linear trend was 2.2, while for the arid steppe zone of the Torey endorheic basin – 1.8. The smallest linear trend of 1.5 was identified for the territory of the Amur Basin. In all studied basins, synchronous cyclicity of precipitation and water levels was revealed against the background of their average annual decrease.

Morphometric Status of River Mu Sub-Basin in Makurdi South, Nigeria

River Mu drainage basin morphometric status is assessed against the backdrop of its characteristics and implication on hydrologic processes operating within the watershed. Geospatial techniques of GIS and Remote Sensing was deployed in the analysis and characterization of the basin morphometric attributes. The result showed Mu drainage basin has an area of 1259.26km2, basin perimeter 240.96km, form factor 0.22, circulatory ration 0.27, and drainage texture 0.51. Mu drainage basin is of 4th order with a dendritic pattern of drainage system indicating the homogeneity in texture and lack of structural control. The stream frequency 0.10 stream segments per square kilometer, drainage density (Dd) 0.40km/km2, bifurcation ratio of 4.62 and length of overland flow of 1.25km. The drainage density, bifurcation ratio and circularity ratio value indicate that the basin is of gentle slope, elongated, high infiltration capacity, low run off and may have longer duration of flow peaks, less susceptible to flooding.

Multi-Variable Location Assessment for Building Modified Stone Concrete Dams in the Drainage Basin of Golpayegan through Fuzzy Logic and Boolean Method, Isfahan, Iran

Multi-Variable Location Assessment for Building Modified Stone Concrete Dams in the Drainage Basin of Golpayegan through Fuzzy Logic and Boolean Method, Isfahan, Iran

УСТАНОВЛЕНИЕ ПОЛОЖЕНИЯ ЗОН ТРЕЩИНОВАТОСТИ И ОБОСНОВАНИЯ ВОЗМОЖНОГО ПОЛОЖЕНИЯ УЧАСТКОВ ПЕРСПЕКТИВНЫХ ДЛЯ ВОДОСНАБЖЕНИЯ НАСЕЛЕНИЯ В БАССЕЙНЕ РЕКИ КЕЛЬВАСАЙ (СЕВЕРНАЯ НУРАТА)

The paper considers the possible use of groundwater for the population water supply of mountain and submontane settlements in certain promising areas based on the application of new method of the reference grid of the Earth planetary faults, reflecting the direction of disjunctive dislocations at regional and local levels. Two sites of increased fracturing which can be considered as potentially promising for groundwater prospecting and organization of geological exploration have been identified within the Kelvasay River drainage basin (Northern Nurata) in the zones of intersection of faults of various directions, according to the universal grid.

Ancient Egypt, Climate and the Nile: A Remark on the First Intermediate Period

The First Intermediate Period in ancient Egypt (22nd–21st centuries B.C.) is characterized by tomb “autobiographies” reporting on low Niles, famine and food donations from high officials and wealthy persons to the poor population after the collapse of the centralized monarchy. Egyptologists have expressed doubts that these sources reflect the real environmental and socio-political situation in Egypt at that date. In the 1970s B. Bell put forward a hypothesis about a severe and prolonged drought that struck in the late 3rd millennium B.C. the Middle East, including the Nile drainage basin; this led to a sharp drop of the Nile floods and, as a consequence (in Bell’s opinion), to the catastrophic decline of the Old Kingdom state. Egyptologists’ rejection of these theses and, in general, the interpretation of historical events of that era in the context of any environmental changes has recently acquired a particularly radical form, up to the revision of the most traditional Egyptological views on the First Intermediate Period, which is now even argued to have not been the time of the deepest crisis of the pharaonic civilization. Numerous independent scientifical studies, however, do not allow denying the important role of the natural factor at certain moments in the history of ancient Egypt, in particular, at the bifurcation between the Old and Middle Kingdoms. From the point of view of the socio-natural history, this was a socio-ecological crisis, a catastrophe that transformed qualitatively the systemic foundations of ancient Egyptian civilization at this stage of its evolution.

Geochemical modeling and hydrochemical analysis for water quality determination around mine drainage areas.

Water sources in mining areas do not retain their natural quality due to the influence of mine drainage. Water quality test was through hydrochemical analysis, speciation modeling, and saturation indices. Water samples were analyzed for pH, conductivity, nitrate, phosphate, sulfate, chlorite, sodium, magnesium, calcium, turbidity, total hardness, lead, zinc, iron, copper, cadmium, manganese, nickel, and chromium. Mean values of turbidity (0.13 mg/L), lead (0.01 mg/L), and cadmium (6.40 mg/L) exceeded their permissible values for potable water. Multivariate statistical analysis shows geogenic and anthropogenic sources of chemical species. Chemical speciation shows that the cations exist mostly in their soluble and mobile forms as free ions. Water quality index of 35-45.5 shows good water for drinking, irrigation, and industrial uses. The values of 63.8-68.8 and 103-121 reflect suitable water for industrial and irrigation uses. The research is integrated and credible in predicting groundwater pollutants to solve water pollution problems. PRACTITIONER POINTS: The mean value of turbidity, Pb, and Cd exceeded the WHO/NSDWQ standards for potable water. Correlation and principal component analyses show that the chemical species are from both geogenic and anthropogenic sources. Chemical speciation shows that the cations exist in their soluble and mobile forms as free ions except Cr. Saturation indices show that the minerals anhydrite, anglesite, vivianite, langite, larnakite, melanterite, and mirabilite are undersaturated in the water sources. Water quality index shows that the water is more suitable for irrigation than drinking and industrial uses.

Assessment of the Potential Flood Hazard of the Larbaâ Wadi, Rural Center of Sebt Boukellal, Taza, Morocco

Flood risk management often requires the use of geomorphological features to identify flood zones, and the use of hydraulic models to predict inundation dynamics and related impacts on the surrounding area. In this study, we used a hydraulic river simulation model to identify potential flood-prone zones on a small scale. It concentrated on a 2.5-kilometer section of the Larbaâ Wadi, which crosses the rural center of Sebt Boukellal. For estimating the peak discharge that occurs in the return periods of 10, 20, 50, and 100 years of the drainage area, we used the Rational method. Standard tables to estimate Manning’s coefficient and direct field measurements to feed the model. Model simulation has shown stability of the steady state, which witnesses the accuracy of the estimated and measured characteristics of the river system. During the calibration phase, we compared the model outputs to the observed floods and made adjustments to align the simulation with the field observations. Indeed, the 50-year flood remarkably matched the extent of the flood that occurred on September 27, 2000. The obtained results have shown that even for a 10year return period, the overflow affects properties within the floodplain. The 100-year flood exceeded the river’s capacity, causing water to spill onto the rural center’s streets and cultivated fields. The water level reached an elevation of 552.14 meters at Sebt Boukellal’s marketplace. These results were consistent with recent floods and confirm previous observations, indicating that the model precisely predicted the river’s behavior. The findings have shown that floods spanned large regions and suggested urgent intervention to protect lives and properties.

Mercury in the landscape components of the Don River Delta

The Don River Delta acts as a protective environmental barrier to the washout of pollutants from adjacent drainage areas. The priority pollutant is mercury, which comes as an industrial, agricultural and domestic wastewater`s part. The mercury concentrations levels in soils were determined by expeditionary and laboratory studies: the indicators ranged from 0,025 to 0,082 μg/g d.m. in the sandy-psammophyte meadow (section №1), in the sandy steppe (section №2) – from 0,012 to 0,022 μg/g d.m., in the true meadow (section №3) – from 0,027 to 0,4 μg/g d.m. and on the landscape with near-water vegetation (section №4) – from 0,035 to 0,565 μg/g d.m. The mercury accumulation in soils according to concentration coefficients is noted in the series «the Near-water landscape(13,5) > the True meadow landscape(5,9) > the Sandy-psammophyte meadow landscape(2,5) > the Sandy steppe landscape(1)». It was found that the soil moisture increased from the section №1 to the section №4 (on average from 18,06 to 35,4%), and the highest total biomass was recorded on the sandy-psammophyte landscape (46,55 t/ha) and the landscape with near-water vegetation (41,85 t/ha).

Application of Multivariate Statistical Methods for Determining Geochemical Trends of Elements on the Territory of Slovenia

The main objective of this study is to map multi-element geochemical anomalies in soil on a regional scale. We aimed to determine and evaluate the baseline geochemical values and main geochemical trends in soil that may serve as reference values against any future changes. A total of 817 topsoil samples (0–10 cm) were collected in a 5 × 5 km grid and analyzed for 35 elements using ICP-ES after multi-acid digestions (HClO4/HNO3/HCl/HF) and 53 elements using ICP-MS after modified aqua regia digestion (HCl/HNO3/H2O). The analytical results for the two different digestion methods (multi-acid digestion vs. aqua regia) were also compared for each chemical element. Multivariate statistical methods were applied to identify the geochemical trends and main sources of trace elements over the territory of Slovenia. Based on these results, seven natural and one mixed natural/anthropogenic geochemical association were established. The contents and trends of the determined factors are presented according to 8 natural units, 4 drainage areas, and geological units characteristic of Slovenia. The identified anthropogenic geochemical association combines toxic elements (Ag, Bi, Cd, Hg, P, Pb, S, Sn, and Zn). Increased values of these elements can be found in mining areas and metallurgic centers, in Quaternary sediments of the Sava River, and Adriatic Basin as the consequence of past mining activities and in the Julian Alps, where their origin could be connected to the atmospheric deposition.

Quantitative morphometric analysis of streams in extreme humid areas a case study of the Um-Mawiong river basin, Mawsynram, Meghalaya

Quantitative morphometric analysis of the drainage system is essential to characterising a watershed, as all the hydrologic and geomorphic processes occur within the watershed. Consequently, this plays a crucial role in understanding the geo-hydrological attributes of a drainage basin to the terrain feature and its flow patterns, thus enabling the estimate of the incidence of infiltration and runoff and other related hydrological characteristics of a watershed, which strongly impacts natural resource conservation. The study area selected is the Um-Mawiong River basin in Mawsynram, Meghalaya. The basin shows a dendritic pattern that highlights the homogeneity in the texture of the basin. Results suggest that the stream frequency of the basin is 19.10 km², suggesting a faster surface runoff and less infiltration. In addition, it has an Elongation ratio of 0.75 indicating an elongated basin shape. The current study demonstrates that the implementations of GIS techniques are trustworthy, efficient, and capable of managing extensive databases for managing river basins. The present study tries to analyse the linear, areal and relief aspects of the basin using a GIS environment and manipulated for different calculations. The analysis reveals that the total number of stream segments and length are maximum in first-order streams and decrease as stream order increases. The drainage density exhibits a high degree of positive correlation, i.e., 0.87, with its frequency suggesting an increase in stream population concerning increasing drainage density and vice versa.

Pulse power plasma stimulation: A technique for waterless fracturing, enhancing the near wellbore permeability, and increasing the EUR of unconventional reservoirs

The inherent characteristic of unconventional and ultra-low permeability reservoirs is a small drainage area that negatively affects the production rate and ultimate recovery (UR). Drilling horizontal wells, coupled with a stimulation process such as hydraulic fracturing, are applied to wells in these reservoirs to enhance well productivity. Although hydraulic fracturing has been the most famous stimulation technique in these reservoirs and has contributed to the increased US oil and gas production during the last several years, other stimulation techniques may be competitive with (or complementary to) hydraulic fracturing. This is because the main contribution to production in these reservoirs would be from complex fracture networks (often micro-cracks) combined with enhanced formation permeability rather than the classical two-wing fractures. Hence, a near-wellbore stimulation technique for improving the permeability of these reservoirs by activating the existing natural fractures and creating secondary microfractures would be highly desired. This paper investigates the pulse plasma stimulation technique to investigate such an approach of waterless stimulation/fracturing that creates multiple fractures and is also a permeability enhancement method. In this method, plasma is generated by discharging a high voltage and high current electrical energy in a very short time into two electrodes submerged in a wellbore filled with aqueous fluid. This study is divided into two sections. The first part presents experimental and numerical examples of stimulation/fracturing induced by pulse plasma in different rocks. Several parameters, including the effect of discharge with and without wire, input energy, confining stress, and rock type, on the induced fractures are studied. The second part uses the insights and results from the first part to numerically investigate pulse plasma's effects on production. Measurement of the formation permeability around the generated fractures indicated that the shock wave generated multiple fractures and increased the rock permeability by more than one or two orders of magnitude. The second part of the numerical section discusses the increased estimated rate and ultimate recovery (EUR) of horizontal wellbores due to fracturing and modified permeability resulting from pulse plasma. We present a sensitivity analysis on the magnitude and extent of the improved permeability region and its impact on EUR.