River Depth Research Articles

Seasonal and spatial variability in δ18O and δD values in waters of the Godavari River basin: Insights into hydrological processes

Study regionThe Godavari River is the largest non-Himalayan, monsoon-fed river in India, providing water resources for ∼75 million people. Study focusStable isotopes of Godavari River water in a pre-monsoon (dry) and monsoon (wet) season are used to evaluate seasonal and spatial dynamics and gain insights into hydrological processes, provenance and pathways of river water from source to sea. New hydrological insightsGodavari River water isotopes shift from an evaporation- to precipitation-controlled signature between the pre-monsoon and monsoon season (p ≤ 0.001). Godavari waters plot below Global and Local Meteoric Water Lines (p ≤ 0.01), highlighting the importance of evaporation. In the monsoon season, low δ18O and δD values in the downstream catchment reflect an amount/convective effect caused by Southwest monsoonal rainfall. Continuously enriched signatures in the Upper Godavari suggest year-round evaporation due to a rainfall deficit and abundant dams creating stagnant waters. The Godavari ultimately discharges an integrated, monsoon signal into the Bay of Bengal. River depth profiles reveal that Godavari waters are well-mixed in both seasons. In the pre-monsoon season, Godavari water isotopes suggest basin-wide evaporation and seawater intrusion in the delta. A data compilation (n = 399) of δ18O and δD values in Indian Rivers reveals a strong seasonality for the Godavari River. The spatio-temporal patterns in Godavari River water isotopes confirm their suitability as sensitive recorders of monsoon precipitation variability and hydrological processes within monsoon-fed rivers.

Water Discharge and River Depth Measurement Using Fuzzy Logic Based on Internet of Things

Based on statistics from Indonesian National Board for Disaster Management (BNPB) there are still many casualties caused by drifting or drowning in rivers every year. This is because most victims do not have sufficient information related to water discharge and river depth. In an effort to reduce the potential victims of these problems, a prototype was designed to provide a warning regarding river status as a display in the detail condition of the river in real-time. In this research, a prototype measuring instrument was produced that could provide information on water discharge and river depth in a sustainable and real-time manner. The prototype device consists of two main sensors as an implementation of internet of things, a water flow sensor and an ultrasonic sensor. Water flow sensor used to calculate the water discharge, and ultrasonic sensor used to measure depth of the river. Fuzzy logic has been used because it can work well for simple classification and work similarly like human reasoning. This information can be monitored through the website and LCD attached on the device. The results of the study with the help of the Linear Congruential Generator (LCG) method indicated that greater input value of the water discharge and the river depth caused more dangerous of the river status. Whereas the prototype produced has an error range of 5-6 cm for depth information generated by the ultrasonic sensor while the accuracy of the water flow sensor on the master device is 79.75% and the slave device is 84%.

What matters most? Stakeholders’ perceptions of river water quality

The need to integrate stakeholders’ views into environmental policy is increasingly gaining attention because this offers the opportunity to design sustainable and synergistic environmental strategies. Understanding and integrating the views of resource users into policy design and implementation could help address the most important challenges, gain community support, enhance project ownership, and avoid policies being rejected by local people. As a result, research in environmental management has focussed on stakeholders’ perceptions of river water quality and how to integrate such views into policy. While existing studies offer insights into the different ways in which stakeholders evaluate river water quality and potential factors influencing judgements, they appear to be limited in a number of ways. First, most of these studies focus on developed countries and may have limited contextual relevance to the developing world. Moreover, past studies focus on segments of society such as farmers and mainly on wastewater for agriculture. These shortcomings may limit our understanding of the topic and our ability to design effective policies to address water quality problems. Drawing on survey data from the Wenchi municipality in Ghana, we examine public perceptions of what constitute important measures of river water quality as well as factors influencing such judgements. Results suggest that while variables such as taste, colour, smell and litter are important, the presence of faecal matter in and/or around the river was rated the most important measure of river water quality while depth of river was the least important. Results further suggest that education, age, number of years a person had lived in a community, depth of river and the presence of aquatic vegetation influence water quality judgements. The findings of this research provide insights into what policymakers and regulators need to consider when attempting to influence behaviours in relation to water resources. We note, however, that while public perceptions of river water quality could guide water management policies, scientific measurements of water quality must not be replaced with stakeholder perceptions. This is because aspects such as ecological integrity may not be important to segments of the public but are an important aspect of water management. This is reinforced in the present study as there seems to be a lack of concern among the participants regarding river depth – an important factor for habitat provision and pollution dilution.

ANALISIS BATIMETRI SUNGAI SERANG UNTUK MENDUKUNG PENGEMBANGAN INFRASTRUKTUR YOGYAKARTA

One criteria of a good infrastructure is to connect land, sea, and air transportation routes. To support good infrastructure in Yogyakarta, the development of Tanjung Adikarto port, located close to New Yogyakarta International Airport, is needed. Instead of having a good port infrastructure, Tanjung Adikarto Port experience sedimentation due to various factors. One of them is sediment carried by Serang River. Therefore, this study aims to analyze Serang River bathymetry and interpolate location of sedimentation in Serang River. The method of bathymetry analysis used is by testing the accuracy of the depth measurement data and interpolate the sedimentation location based on the transverse and longitudinal profile of the Serang River. In addition, Serang River tidal data analysis was also carried out and development problems in Tanjung Adikarto Port is also evaluated. The results of this study indicate that the tides still affect the dynamics of the Serang River up to about 1 km from the Tanjung Adikarto Port breakwater area. According to IHO standards, Serang River depth measurement data classified as Order 1, while sedimentation occur in the river bank area and around the entrance of Tanjung Adikarto Port. As for infrastructure development problem, Tanjung Adikarto Port sedimentation problem might be caused by breakwater conditions. However, this may requires further study.

A Framework for Modeling Flood Depth Using a Hybrid of Hydraulics and Machine Learning

Solving river engineering problems typically requires river flow characterization, including the prediction of flow depth, flow velocity, and flood extent. Hydraulic models use governing equations of the flow in motion (conservation of mass and momentum principles) to predict the flow characteristics. However, solving such equations can be substantially expensive, depending upon their spatial extension. Moreover, modeling two- or three-dimensional river flows with high-resolution topographic data for large-scale regions (national or continental scale) is next to impossible. Such simulations are required for comprehensive river modeling, where a system of connected rivers is to be simulated simultaneously. Machine Learning (ML) approaches have shown promise for different water resources problems, and they have demonstrated an ability to learn from current data to predict new scenarios, which can enhance the understanding of the systems. The aim of this paper is to present an efficient flood simulation framework that can be applied to large-scale simulations. The framework outlines a novel, quick, efficient and versatile model to identify flooded areas and the flood depth, using a hybrid of hydraulic model and ML measures. To accomplish that, a two-dimensional hydraulic model (iRIC), calibrated by measured water surface elevation data, was used to train two ML models to predict river depth over the domain for an arbitrary discharge. The first ML model included a random forest (RF) classification model, which was used to identify wet or dry nodes over the domain. The second was a multilayer perceptron (MLP) model that was developed and trained by the iRIC simulation results, in order to estimate river depth in wet nodes. For the test data the overall accuracy of 98.5 percent was achieved for the RF classification. The regression coefficient for the MLP model for depth was 0.88. The framework outlined in this paper can be used to couple hydraulics and ML models to reduce the computation time, resources and expenses of large-scale, real-time simulations, specifically for two- or three-dimensional hydraulic modeling, where traditional hydraulic models are infeasible or prohibitively expensive.

Hydrodynamic Controls of Particulate Metals Partitioning Along the Lower Selenga River—Main Tributary of The Lake Baikal

In this study, the downstream effects of pollutants spreading due to hydromorphological gradients and associated changes in sediment transport conditions along the braided-meandering and deltaic distributary reach of a large river downstream section are discussed. We demonstrate the significance of hydrodynamic control for sediment-associated metal partitioning along the river. Typically, the downward decline of the sediment and metals spreading towards Lake Baikal is observed due to buffer effects in the delta. During peak flow, the longitudinal gradients in heavy metal concentration along the distributary delta reach are neglected due to higher concentrations delivered from the upper parts of the river. In particular, significant variations of heavy metal concentrations associated with the river depth are related to sediment concentration and flow velocity profiles. Various particulate metal behavior in silt-sand delta channels and the sand–gravel Selenga main stem emphasize the importance of near-bottom exchange for particles spreading with the river flow. Using empirically derived Rouse numbers, we found quantitative relationships between the ratio of particulate metals sorting throughout depth in a single river channel and the hydrodynamic conditions of sediment transport.

A review of approaches for water depth estimation with multispectral data

AbstractThe purpose of this paper is to give an exhaustive assessment of water depth estimation in shallow inland and coastal water environments with the assistance of optical remote detecting procedures, utilizing satellite/airborne multispectral information. Remote sensing has been used to map bathymetry for several decades. Inaccessibility, large‐scale depth mapping, very shallow areas, and cost constraint are some of the reasons why remote sensing technique is a boon for bathymetry. Researchers have come a long way since the remote sensing‐based bathymetry has been used. Fourfold increase in spatial, spectral, radiometric and temporal resolution of sensors have also increased the accuracy. There are two types of remote sensing techniques; Active and Passive. Active remote sensing includes the use of ground penetrating radar and bathymetric lidar, which are expensive but precise surveys successful up to 70 m depth. On the other hand, passive remote sensing deals with water photogrammetry and radiometric methods done by capturing imagery with space borne/air borne platforms having depth penetration up to 25 m. The latter technique includes finding of a logarithmic relationship between river depth and image values. This technique is most widely used because of its cost effectiveness. In this paper, the emphasis has been given to derive bathymetric techniques using multispectral data as these methods have proved reasonably successful when water quality, bottom reflectance, and atmospheric effects are all invariant. At a specific area, the detection of possible changes in water flow and levels indicates flow path changes which can be used to predict potential surface level flooding for better water management and policy decisions.

Elevation gaps in fluvial sandbar deposition and their implications for paleodepth estimation

Abstract Accurate estimation of paleo–streamflow depth from outcrop is important for estimation of channel slopes, water discharges, sediment fluxes, and basin sizes of ancient river systems. Bar-scale inclined strata deposited from slipface avalanching on fluvial bar margins are assumed to be indicators of paleodepth insofar as their thickness approaches but does not exceed formative flow depths. We employed a unique, large data set from a prolonged bank-filling flood in the sandy, braided Missouri River (USA) to examine scaling between slipface height and measures of river depth during the flood. The analyses demonstrated that the most frequent slipface height observations underestimate study-reach mean flow depth at peak stage by a factor of 3, but maximum values are approximately equal to mean flow depth. At least 70% of the error is accounted for by the difference between slipface base elevation and mean bed elevation, while the difference between crest elevation and water surface accounts for ∼30%. Our analysis provides a scaling for bar-scale inclined strata formed by avalanching and suggests risk of systematic bias in paleodepth estimation if mean thickness measurements of these deposits are equated to mean bankfull depth.

A cosmogonia amazônica na poética do imaginário de João de Jesus Paes Loureiro

Este trabalho analisa os traços da cosmogonia amazônica presentes na poética do imaginário de João de Jesus Paes Loureiro. O autor da cidade de Abaetetuba no Pará viveu parte da sua infância às margens das ilhas e carrega, na sua escrita, traços memorialísticos das narrativas míticas ribeirinhas. Assim, sua formação cultural e intelectual é marcada pela poética das águas. O estudo possui em seu corpus analítico passagens de poemas como “Paisagem mítica”, “Abaetetuba sempre”, “A história luminosa e triste do Cobranorato”, “Cantar da Iara”, entre outros. Para identificar os traços mais representativos da cosmogonia amazônica, o estudo dialoga com autores do campo da mitologia, do imaginário e da cultura amazônica. A análise de poemas se pautou em uma leitura discursiva e narratológica a partir dos estudos culturais. A pesquisa selecionou uma corpora poética a fim de ler os traços cosmogônicos da Amazônia na poética do autor. Nesse sentido, embasou-se em autores como Eliade (1963), Pizarro (2012) e no próprio Paes Loureiro (2000) como teórico de si. Desse modo, as narrativas míticas surgem como vivência e forma de explicação da complexa formação do universo amazônico, constituída de narrativas que dão voz aos povos dessa região. As cenas culturais evocam, neste estudo narratológico, seres encantados das profundezas dos rios, das florestas e legitimam a cosmologia das encantarias, categorizada por Paes Loureiro como poética estetizante. Com isso, por meio da escrita poética desse autor, este artigo identifica as relações entre a natureza e as narrativas míticas, observando o regime das águas como fenômeno que exerce grande influência sobre a vida do caboclo amazônico, seja no modo de ver ou de construir a gênese da (re) criação do mundo e dos seres amazônicos.

Changes in maximum daily runoff depth and suspended sediment yield on the Loess Plateau, China

The maximum river flow is of important reference significance to flood disaster prevention on the Loess Plateau of central China. However, due to the lack of hydrological data, previous studies have rarely explored spatiotemporal changes in the annual maximum daily runoff depth (Hmax) and annual maximum daily suspended sediment yield (SSYmax) of rivers in this region. This study uses daily discharge data and daily sediment concentration data from 104 hydrological stations on the plateau to compare the Hmax and the SSYmax during period P1 (1971–1987) and period P2 (2008–2016). The results show that 66% of stations exhibited a significant decline in multi-year mean Hmax from P1 to P2 (p < 0.05). However, the multi-year mean SSYmax showed more widespread changes, with 77% of stations seeing a significant decline (p < 0.05). And on average, the runoff on the day of Hmax contributed 6.6% and 5.8% of the annual runoff during P1 and P2, respectively; by contrast, SSYmax contributed 27.9% and 33.5%, respectively, to the total annual suspended sediment yield in P1 and P2. Analyses using Spearman’s rank correlation coefficient indicate that the spatial distribution of Hmax has larger variability than SSYmax during both P1 and P2 and that the spatial distribution pattern of SSYmax during P2 is more unstable than during P1. We found that the suspended sediment concentration (SSC) on the day that Hmax occurs (SSChmax) remained relatively stable for most stations studied within the loess gullied-hilly area across the Loess Plateau, but the stable SSChmax value during P1 differed from the value during P2. We conclude that human activities (e.g., afforestation, terracing, and construction of check dams) may be the cause of the differing SSC values during peak discharge between the two periods. We also found that the average percentage of years in which Hmax and SSYmax occurred on the same day on the plateau was 55%. Many factors can lead to Hmax and SSYmax happening asynchronously, such as heavy runoff events lasting several consecutive days, the characteristics of a particular basin, and the influence of human activities. These results provide information that will be useful for understanding how to manage extreme hydrological events on the Loess Plateau.

River discharge estimation from radar altimetry: Assessment of satellite performance, river scales and methods

The ENVISAT, Jason-2 and -3, Sentinel-3A, CryoSat-2, and AltiKa satellite altimeters were used to estimate the discharge of two Arctic rivers: the Ob and Pur in western Siberia. The accuracy of the water height estimates from ENVISAT varied with river size from 0.63 m for the Ob (~2 km in width) to 1.1 m for the Pur (~0.5 km in width). A new method for water level estimation combining the CryoSat-2, AltiKa, and Sentinel-3A altimeters provided better height accuracy (0.49 m for the Ob). The rating curve method of discharge estimation outperforms the Manning formulation, on the Ob, with a root mean square error (RMSE) of 13% vs 20% for daily discharge and 1% vs 5% for annual discharge. Sensitivity analysis performed on the Manning formulation showed high sensitivity to the river depth parameterisation. A functional relationship was identified between the depth of rivers, in the north of western Siberia, and their widths and deposits types. The combination, for the Ob, of the rating curve method with the multi-satellite water level retrieval algorithm provided higher discharge accuracy than previous studies relying on satellite measurements, on numerical modelling or on their combination. A synthesis of worldwide river altimetry studies supported our finding that the accuracy of altimetric discharge estimations decreases for narrower rivers. The rating curve method applied to Jason 2/3 height measurements allows estimation of daily discharges with RMSE of 18% for the wide Ob River but 38% for the narrow Pur River.

Analysis of the Badeng River Storage Capacity for Flood Modeling in Singojuruh Subdistrict, Banyuwangi Regency

The Singojuruh flash flood incident have diverse effects on residential and agriculture areas. As result of the 2018 flood, two houses collapsed and there were severe also effects on agriculture. This paper focuses on understanding the river capacity (Badeng River) as well as the modeling to the next flood. We used Hydrological Engineering Center-River Analysis System (HEC-RAS) version 5.0.7 to analyze the river storage capacity. The factor in this analysis i.e. river morphometry (river length, river width, river depth and river slope) and manning coefficient. The sampling conducted in three point along the Badeng River. The result showed that each of point location have different characteristic hence influence its capacity. The smallest capacity has the biggest potential of flooding.

I-Tree cool river: An open source, freeware tool to simulate river water temperature coupled with HEC-RAS

This method paper explains the i-Tree Cool River model algorithms for simulating the response of river water temperature to urban greening. The model captures the warming and cooling impacts of urban development and restoration through a water and energy budget. The water budget includes river inflows from urban storm sewers and reservoirs, and the associated water temperatures. The energy budget adjusts radiation fluxes due to riparian shading and evapotranspiration, and propagates temperature downstream. Restorative cooling of the river can be simulated through algorithms for cool groundwater, either as direct inflows or by river water replacement called hyporheic exchange. Novel features in the model include diurnal variation in riparian shading, use of the Army Corps of Engineers HEC-RAS model predicted river depths and velocities, and periodic boundary conditions to rapidly extend restoration scenarios.•Freely available code in C++ for Visual Studio, with a detailed manual and sample inputs and outputs at http://www.itreetools.org/research_suite/coolriver.•Useful for simulating river warming or cooling due to urban development or greening.•Well documented source code compatible with requirements of other modeling groups.

From Andes to Amazon: Assessing Branched Tetraether Lipids as Tracers for Soil Organic Carbon in the Madre de Dios River System

AbstractWe investigate the implications of upstream processes and hydrological seasonality on the transfer of soil organic carbon (OC) from the Andes mountains to the Amazon lowlands by the Madre de Dios River (Peru), using branched glycerol dialkyl glycerol tetraether (brGDGT) lipids. The brGDGT signal in Andean soils (0.5 to 3.5 km elevation) reflects air temperature, with a lapse rate of −6.0 °C/km elevation (r2 = 0.89, p &lt; 0.001) and −5.6 °C/km elevation (r2 = 0.89, p &lt; 0.001) for organic and mineral horizons, respectively. The same compounds are present in river suspended particulate matter (SPM) with a lapse rate of −4.1 °C/km elevation (r2 = 0.82, p &lt; 0.001) during the wet season, where the offset in intercept between the temperature lapse rates for soils and SPM indicates upstream sourcing of brGDGTs. The lapse rate for SPM appears insensitive to an increasing relative contribution of 6‐methyl isomer brGDGTs produced within the river. River depth profiles show that brGDGTs are well mixed in the river and are not affected by hydrodynamic sorting. The brGDGTs accumulate relative to OC downstream, likely due to the transition of particulate OC to the dissolved phase and input of weathered soils toward the lowlands. The temperature‐altitude correlation of brGDGTs in Madre de Dios SPM contrasts with the Lower Amazon River, where the initial soil signature is altered by changes in seasonal in‐river production and variable provenance of brGDGTs. Our study indicates that brGDGTs in the Madre de Dios River system are initially soil derived and highlights their use to study OC sourcing in mountainous river systems.

The Sprainting Behavior and Habitat Preference of the Eurasian Otter Lutra lutra Along a Montane Stream in South Korea

Although the Korean population of Eurasian otter (Lutra lutra) was designated as an endangered species, habitat and basic ecology of Korean otters have been rarely known. To ascertain sprainting behavior of the Eurasian otter in the freshwater habitat and investigate the habitat preferences, otter surveys along the Ungok River in Gyeongsangbuk-do, South Korea, were conducted for a 12-month period during 2002 and 2003. Seasonal fluctuations of the number of spraints and sprainting sites along the river were identified. The number of spraints and sprainting sites peaked in March. General linear models indicated site-dependency in the numbers of spraints and sprainting sites. The general linear mixed model indicated that the numbers of spraints (or sprainting site) were positively correlated with vegetations on riverbanks and river depth. Although human impact and river width were significantly related to the number of spraints, they did not show significant relationship to the number of sprainting sites. Despite several coincidence with studies in Europe, sprainting behavior by otters along a montane river in South Korea suggested differences in regional and spatial level. This ecological information on the Korean population of the Eurasian otter will assist the investigation of population size and help habitat management for otters.

ASIATIC SMELT OSMERUS DENTEX STEINDACHNER ET KNER, 1870 OF THE UDA RIVER (NORTHWESTERN OKHOTSK SEA) — BIOLOGY, ECOLOGY, FISHERY

Data on biology, ecology and fishery of asiatic smelt in the Uda River during its spawning migration are analyzed. The spawning begins in May-June in 2–11 km from the river mouth and lasts 3–10 days. Timing of its start varies from May 22 (2014 and 2018) to June 14 (2001), with 24 days difference. The spawning migration begins under the water temperature 6.0оС, during the spawning the temperature varies from 6.2 to 11.9оС. The river flow velocity on the spawning grounds is 1.2–2.6 m/s, the river depth varies from 0.3 to 2.5 m. Age of the spawners is 2–8 years, their length is 11.5–32.0 cm and weight 10.8–275.0 g, males usually prevail in number (63–81 %). Depending on the year-class strength, the fish in age of 3 or 4 years prevail among the spawners. After spawning, females leave the spawning grounds immediately — in that time their occurrence in the catches below the spawning grounds can reach 85 %. Size of the spawners decreases during the migration, for males the decreasing was from 19.0 to 15.0 cm in 2007, from 20.2 to 18.8 cm in 2014, from 19.3 to 16.6 cm in 2015, and from 19.4 to 16.0 cm in 2016, for females — from 21.0 to 18.0 cm in 2007, from 22.1 to 19.6 cm in 2014, from 21.3 to 19.0 cm in 2015, and from 24.5 to 16.1 cm in 2016. Annual increments of the smelt body length are 0.7–7.8 cm, on average 3.9 cm, for the body weight 17.1–39.9 g, on average 32.1 g. The minimum registered size of mature male and female was 11.5 and 13.0 cm, respectively. Percentage of the smelt with non-commercial size during spawning migration was 19.2 % in 2007, 0.4 % in 2014, 15.4 % in 2015, and 28.4 % in 2016. The group linear growth of asiatic smelt could be approximated by Bertalanffy equation: L = 30.5 [1 – e–0.317 (t – 0.533)]. Its body length dependence on weight is described by the equation of simple allometry: W = 0.002 L3.380(determination r 2 = 0.92–0.99). The body weight depends on age as the function: Wt = 2.974t2.136. Individual absolute fecundity of the smelt in the Uda varies from 11300 to 141300 eggs, on average 52500 eggs in 2016 and 50400 eggs in 2007; these values are close to the smelt fecundity in the Ulbeya and Inya rivers. The fecundity variation generally increases with the age: the registered ranges of absolute fecundity (thousand eggs) were, by age groups: 19.1 for 3 years, 53.5 for 4 years, 37.8 for 5 years, 57.5 for 6 years, and 60.3 for 7 years old fish, the ranges of relative fecundity (eggs/g of body weight) were: 864, 537, 565, 501, and 449 eggs/g for the same age groups. The total population fecundity was 32.7. 109eggs in 2016. The individual absolute fecundity has the following dependencies on body length, weight, and age: AF(L) = 0.001 L3.437, AF(W) = 0.650 W0.986, and AF(t) = 1.661 t2.250, respectively. The stock of asiatic smelt in the Uda is represented by migrating fish only. Its fishery was conducted by 8 companies, their total annual landing increased from 10 t in 2012 to 373 t in 2017 and slightly decreased recently: the mean landing for 2013–2019 was 276 t. The spawning biomass of smelt was estimated from 637 to 1734 t, by years, that was about 70 % of the biomass of mature smelt in the Shantar Sea.

Climatic control on stacking and connectivity of fluvial successions: Upper Cretaceous Bajo Barreal Formation of the Golfo San Jorge basin, Patagonia

Abstract Climate impact on alluvial organization owing to its control on water availability and sediment delivery within the catchment, but temporal changes in stacking patterns are often interpreted to reflect changes in subsidence and base level. To test for evidence of climatic control on the stacking pattern, we study an outcrop succession with two styles of stacking within the Upper Cretaceous Bajo Barreal Formation in the Cerro Ballena anticline, Golfo San Jorge Basin, Argentina. The 385 m thick and 2.5 km wide exposure has layer-cake geometry, lacking either large-scale erosional surfaces, fluvial terraces, or evident paleosols, dismissing either local tectonic activity or base-levels shifts. Rooted in a paleohydrological study recognizing upward increasing in both channel width and flow depth of formative rivers, we use spectral gamma-ray logs, x-ray diffraction in mudstones, and sandstone petrography to understand the controls on the stacking pattern. At the base, Section A consists of small-scale, isolated channels fills in a siliciclastic floodplain with sand:mud ratio of ~1:6, whereas the overlying Section B has a sand-mud ratio of ~1:3, with larger-scale channels and greater inter-connectivity within a volcaniclastic floodplain. Upward reduction in K percentage through Section A parallel with increasing kaolinite content, and mudstone samples from Section B contains a higher proportion of kaolinite than Section A samples, evidencing an upward increase in paleo-weathering in humid conditions. Detrital components of Section A indicate several volcanic sources (e.g., basic-intermediate components derived from the Middle Jurassic Bahia Laura Group and acidic components sourced from the Andes Cordillera), whereas Section B exclusively contains acidic clasts derived from the Andes Cordillera. Simultaneous changes in detrital constituents, suspended load type, and increasing scale of the rivers in Section B occur coeval with increases in channel inter-connectivity, here related to the increase of river discharge and sediment supply in a humid climate, favoring more frequent avulsions or higher channel migration rates in a relatively flat geomorphic scenario. The study demonstrates, combining independent lines of evidence, that climate change can impact the stacking and connectivity of potential sandstone reservoirs.

Interacting effects of vessel noise and shallow river depth elevate metabolic stress in Ganges river dolphins

In riverine ‘soundscapes’, complex interactions between sound, substrate type, and depth create difficulties in assessing impacts of anthropogenic noise pollution on freshwater fauna. Underwater noise from vessels can negatively affect endangered Ganges river dolphins (Platanista gangetica), which are ‘almost blind’ and rely entirely on high-frequency echolocation clicks to sense their environment. We conducted field-based acoustic recordings and modelling to assess acoustic responses of Platanista to underwater noise exposure from vessels in the Ganga River (India), which is now being transformed into a major waterway. Dolphins showed enhanced activity during acute noise exposure and suppressed activity during chronic exposure. Increase in ambient noise levels altered dolphin acoustic responses, strongly masked echolocation clicks, and more than doubled metabolic stress. Noise impacts were further aggravated during dry-season river depth reduction. Maintaining ecological flows, downscaling of vessel traffic, and propeller modifications to reduce cavitation noise, could help mitigate noise impacts on Ganges river dolphins.

An initial analysis of two western rivers’ turbulent-flow-induced noise

This talk describes noise characteristics near turbulent sections of the Provo and Colorado Rivers in Utah. For reference, these rivers are characterized as medium-sized bedrock rivers, with Strahler orders of 5 and 7, respectively. Larson Davis 831C sound level meters were used to obtain two-second, one-third octave time histories within several meters of the bank at different locations and different times of day. Along the Provo River, the low-frequency content (below 250 Hz) varies with time of day and is likely contaminated by anthropogenic noise sources. The high-frequency noise (above 250 Hz) spectral shape is remarkably similar for every measurement; this spectrum is possibly characteristic of turbulent flow in smaller rivers. However, a measurement near a Colorado River Class III rapid reveals significantly more low-frequency spectral content, but similar high-frequency behavior. Initial efforts to correlate noise with available physical data on both river systems such as flow rates, river depths, river gradient, and terrain composition are described.

Can Bankfull Discharge and Bankfull Channel Characteristics of an Alluvial Meandering River be Cospecified From a Flow Duration Curve?

AbstractWe present a simple modeling framework for the codetermination of bankfull discharge and corresponding bankfull channel geometry (width, depth, and longitudinal channel slope) of an alluvial meandering river. We specifically consider a sand‐bed river whose floodplain is capped by a mud‐rich layer. We inquire as to how the wide spectrum of flows to which the river is subjected leads to the establishment of specific values for bankfull discharge and associated bankfull geometry. Here we provide a physically based predictor of bankfull discharge that goes beyond the simple assumption of the 1.5‐year flood discharge. We do this using physics‐based submodels for channel and floodplain processes. We show that bankfull discharge and bankfull geometry are established as a result of (i) floodplain vertical accretion due to overbank deposition, (ii) migration of the inner bank and outer cut bank, (iii) net removal of floodplain sediment and reduction in average floodplain height due to lateral channel shift, and (iv) in‐channel downstream bed material transport. The flow duration curve is employed to quantify the effect of these processes, as well as to account for flow variability. Our model captures the spatiotemporal evolution of bankfull discharge, depth, width, and down‐channel slope toward equilibrium for specified flow duration curve and watershed characteristics. Our new framework can be used for assessing long‐term river response to change in sediment supply or flow duration curve. A model implementation is presented for the case of the Trinity River, TX, USA, to demonstrate the use of the model and its behavior.