Fluvial Hydraulics

Major river valleys (e.g. Ganga, Brahmaputra, Narmada, Godavari, Kosi etc.) of India have remained as cradles of human livelihood and achievements throughout the course of human history. In the same way, contributing with floods the Damodar valley of eastern India is nurturing its civilization in different phases through almost 3,500 year. Documented history of ruinous extreme floods is more than 347 years old (1665 – 2012) in the Damodar River. It is true that when this river is in the extreme phase, none can withstand against its power. Still we are not now fully capable to manage the adamant nature of river particularly in the monsoon period. Simultaneously the uncertain event, e.g. cloud burst, heavy monsoon rainfall and cyclones etc., and resultant flash floods are not forecast accurately. As the catchment of Damodar has good physiographic and hydro-meteorological potentiality of floods, it is imperative to know the current status of flood probability and risk. So here an attempt is made to investigate the temporal variation (i.e. natural phase – without dams and controlled phase – with dams) of annual peak flows understanding the dam induced flood hydrological changes in the Damodar River. Using the quantitative techniques, viz., Flood Potential Index (FPI), Flash Flood Magnitude Index (FFMI) and Flood Frequency Analysis (FFA), the magnitude of flash floods and channel dimensions are analyzed to derive significant explanation and prediction about the flood risk in the lower segment of Damodar River.

La Valle del Turano (quota media 535 m s.l.m.) si sviluppa in direzione NW-SE al margine occidentale della dorsale appenninica, al confine con l’Abruzzo; essa fa parte del bacino idrografico del Tevere. Il Turano nasce in prossimità dell’area industriale di Carsoli (AQ), nella Piana del Cavaliere, dalla confluenza  tra il Fosso Secco-Cammarano, proveniente dalla Valle del Fiojo, e da un torrente alimentato da alcune sorgenti poste al Valico di Monte Bove (1220 m).
L’orografia del tratto vallivo è caratterizzata  a Ovest dalla dorsale di M. Faito (1221 m) – Colle Lepre – Rocca Pennino – Muro Pizzo appartenente ai Monti Lucretili (settore dei Monti Sabini) e a Est dalla dorsale M.Cervia (1430 m) – M.Navegna (1508 m) del gruppo dei Monti Carseolani.
La storia geologica della Valle del Turano rientra in quella più generale e articolata della catena appenninica centrale, la quale costituisce una fascia crostale intensamente deformata in seguito a diverse fasi tettoniche di età neogenica sviluppatesi come conseguenza dello scontro tra la Placca Africana e quella Europea. Le fasi tettoniche che hanno interessato questo settore sono state dapprima di tipo compressivo (Miocene sup./Pliocene inf., 12-13 Milioni di anni fa), con la conseguente formazione di rilievi. A partire dal Pliocene inferiore-medio la catena appena strutturata è stata interessata da un intensa fase tettonica distensiva, con la formazione di numerose faglie dirette che hanno ribassato ampi settori della catena. Ne sono derivate una serie di depressioni morfologiche (valli e conche intramontane) che nel Pliocene superiore-Quaternario hanno raccolto grossi depositi di materiali terrigeni (fluviali, lacustri, ecc.), come è il caso della Valle del Turano.
Questa, prima molto ampia e scavata in gran parte in marne e calcari marnosi, si fa bruscamente stretta e profonda, incisa in rocce calcaree. E’ proprio con lo sbarramento di questa stretta gola dalle pareti a picco, che hanno fornito solide spalle per la diga, che si è realizzato il lago artificiale del Turano. La diga del Turano fu finita nel 1939, costruita in calcestruzzo, è di tipo a gravità massiccia con pianta leggermente arcuata.

I discuss results from AERA work at the Heit el-Ghurab (HeG) site and at the Khentkawes Town (KKT) and relate those results to discussion, observations, and conclusions about the floodplain and Nile flood levels at Dahshur, in the Memphis/Saqqara area, near Giza, and points northwest in the region of Ausim and Abu Roash, with an emphasis on the Old Kingdom.

Each geomorphic hazard involves a degree of risk which incorporates quantification of the probability
that a hazard will be harmful. At present, the categorization of sub-watersheds into erosion risk is considered
as the fundamental step to conserve the soil loss. Development of badlands over the laterites of
Birbhum district is an indicative of excessive soil loss in the monsoonal wet-dry type of climate. Slope
erosion and channel erosion have generated huge amount of sediment from the small watersheds during
intense monsoonal rainfall (June–September). The adjoining areas of Rampurhat I Block, Birbhum
(West Bengal) and Shikaripara Block, Dumka (Jharkhand) have lost the lateritic soil cover at a rate of
20–40 ton/ha/year (Sarkar et al. 2005). In order to estimate the progressive removal of soil particles from
the gully-catchments of the above-mentioned area, different morphometric parameters, soil parameters,
hydrologic parameters and empirical models are employed. Side by side, the study is carried out to categorize
the gully-catchments into different magnitude of erosion risk using several multivariate statistical
techniques.

El presente trabajo tiene como objetivos específicos (a) Diseñar un sistema de defensa ribereña, que permite el control y la protección de las inundaciones y la erosión y (b) Plantear un plan de manejo y conservación de recursos naturales existentes en la cuenca del río Cuyocuyo. El proyecto de defensa ribereña, se localiza en la zona urbana de la ciudad y distrito del mismo nombre, Cuyocuyo, en la provincia de Sandia, departamento de Puno¸ a una latitud Sur 14 ° 28.36 ', longitud Oeste de 69 ° 32.228', la altitud de la localidad es de 3,401 msnm. El proyecto final consiste en el encauzamiento nuevo del río Cuyocuyo, con muros de contención, construído con materiales de la zona, tales como piedra pizarra y tierra orgánica, complementado con cemento. La longitud trazada total es de 1,120 metros. La zona de confluencia con el río Jilari, tiene un diseño con enrocado del fondo en su totalidad, ya que la fuerza de erosión del río Jilari, debido a su fuerte velocidad, es grande. ...

RUSSIAN ACADEMY OF SCIENCES Department of Earth Sciences
Institute of Water Problems
Scientific Council RAN
Russian Foundation for Basic Research Russian
National Committee of the International Association of Hydraulic Research

DINAMICS AND THERMIC OF RIVERS, BASINS AND COASTAL SEAS
VI Conference
PROCEEDINGS
22-26 November 2004 Moscow, Russia


DYNAMICS OF SOME ITALIAN RIVER MOUTHS FOR THE PAST 10.000 years (THE HOLOCENE PERIOD) *

Piero Bellotti  and Publio Valeri

University of Rome «La Sapienza», Department of Earth Sciences, Rome Italy
Dipartimento di Scienze della Terra, Università di Roma «La Sapienza, Roma, Italia)



  At present, many italian rivers form deltas, in microtidal regime, with different morphological and dynamic characteristics.
There are four main types of river deltas in Italy [1] (Fig. 1):

1) delta of limited size, single and unstable distributary channel, and deposits from silt to gravel. These deltas are formed on the narrow shelves in the mouth of rivers with limited drainage basin (river Centa and Crati);

2) delta of limited size, with multiple distributary channels, sediment from clay to sand. Such delta formed in protected areas with moderately steep shelf in the mouths of small rivers (river Isonzo);

3) delta of medium size, single and stable distributary channel, in most cases, and deposits from silt to sand. These deltas are formed on the broad shelf in the mouths of rivers with basin area allo >10.000 km2. These rivers form large strand plain (river Arno, Ombrone, Tiber, Volturno, Tagliamento);

4) delta of large size with many and unstable distributary channels and sediment from clay to sand. Such delta formed in the wide shelf with a weak slope (River Po).

    Deltas are formed when Vm> Vr, where Vm - volume of sediment receipts at the mouth of river, and Vr- amount of sediment carried away by sea  processes. In non-tidal deltas for the time interval Δt relationship exists ± ΔVf = Vd ± Vo-Vi [6], where ΔVf - change in the volume of the fan, Vd- volume of river sediments coming from all delta distributaries, Vo - the amount of sediment carried by the wawes , Vi - the amount of sediment carried offshore or by river plume or by density flow. Let us assume that γd - density of river water, and γb - the density of the receiving waters of the reservoir; if γd<γb, sediments are transported in the river buoyancy  low, and if γd>γb, in the form of density flow.
In marine deltas last condition mets only in exceptional floods, and in the Italian deltas is observed only in the delta of the river Crati [8]. In the absence of relative sea level rise (the sum of eustatic sea level rise and land subsidence) delta extends when ΔVf >0 and is subjected to erosion if ΔVf<0. With a significant relative sea-level rise happens drowning of the sediment prism Va in the process of accumulation. In the interval Δt when ΔVf>0 delta extends, if ΔVf >Va, and shifts to the land if ΔVf >Va.



    Stratigraphic studies on the Italian deltas [2-4, 7] discover that in the process of their development during the Holocene changed fisiographic and dynamic conditions of their formation. Sea levels in the early Holocene, at the end of the last glacial maximum was at 30 m below the present. In the northern part of the Adriatic Sea (shelf with a weak slope) away from the recent mouths already formed a large system of barrier-lagoon-estuary, which receives runoff of various rivers such as the Po, Tagliamento, Adige and Isonzo. On the coast of the Tyrrhenian Sea rivers flow into large rias, partially protected from the sea by sand bars. There rivers built longitudinal delta structures. On most wide shelves, river mouths were already in rias and the delta building not happened. Despite the progressive decrease of eustatic sea-level rise, the mouth shifted landwards until about 6,000 years ago, when sea level began to change, as in the present conditions (1-1.5 mm / year). During this period, estuaries almost everywhere presented broad lagoons or bays, partially bordered by sand barriers. Within these lagoons whose a lot of river mouths. Tyrrhenian rivers carry their deposits directly into the lagoon and built lagoon-delta complexes [1], in other cases, the deposits flowed into the lagoon not regularly, depending on the movement of channels, the most active in areas with severe land subsidence. In the northern part of the Adriatic Sea, the lagoon system was already formed, and it formed  separate delta protrusions [4]. At the mouth of the river Crati river sediments interspersed lagoon clays. About 3,000 years ago, all major Italian river has flowed into the sea, partially filling the lagoon, but has not yet formed a stable marine delta systems. Many small rivers long maintained lagunar mouths, that disappeared only by drying lagoons.
    In the Etruscan period appear the first extensions of the delta, but only in the Roman Empire Period and in the Tyrrhenian and Adriatic seas appear first stable delta bodies, near which there were still large lagoon during the early Middle Ages the Tyrrhenian delta (all single channel) were subjected to partial erosion; in the delta complex of the Po River (with many and unstable channels), some bodies partially were destroyed, partly forwarded in the sea. In XV-XVI centuries delta moving into a phase of active progradation, which lasts until the XIX century. In the mouths of the Tyrrhenian rivers formed delta with beach ridges. Po Delta forwarded into the sea more than 15 kilometers, forming a multi channel system. It confirms the excess energy of the river compared with the energy of waves. At the mouth of the river Centa, delta shifted producing temporary separation of the main channel into two branches. At the mouth of the river Crati began formation of the modern delta and recurrent floods crossed the ancient coastal bars, and the remains of the lagoon turned into swamp (in the lagoon to the III century was the port). In XX century the progress of the delta ends everywhere, and in some cases even a partial retreat of delta lobes begins. By stratigraphic data can be established that between the beginning of the Holocene and the time 6.000 years ago, occur condition ΔVf<Va, in connection with the last phase of eustatic sea level rise. For the last 6.000 years the value Va at eustatic rise becomes small, but
it remains significant at the mouths of rivers Po and Crati as a result of strong subsidence. However, for the period 6000-3000 years ago, at the mouth of the Po river changed dynamics of the delta, and for SΔVf>Va (S characterizes majority of mouths) was a phase of progress; at the mouth of the river Crati similar phase was not, as the formation of the delta, apparently occurred under ΔVf ~ Va. In Tyrrhenian mouths value of Va was small, ΔVf values were sufficient to advance of lagoon deltas. Over the last 3,000 years, despite an increase in the values of Vo and Vi, corresponding to the position of sea level in the all mouths, the values ΔVf increase and development of deltas occur anywhere under the conditions ΔVf>Va. Especially in the second half of the XX century occurs condition ΔVf >> Va, which corresponds to the most intense phase of progress of the major deltas Italy. Later there were still periods of negative values ΔVf, defined by data of erosion of the delta lobes. Changes ΔVf in this period is mainly dependent on the fluctuations of Vd to the result of the change of different climatic phases or human impact.



REFERENCES
Bellotti Р. Il modello morfo-sedimentario dei maggiori delta tirrenici. Boll. Soc. Geol. It 2000. 119. 777-792.
Bellotti Р., Chiocci F.L., Milli S., Tortora Р., Valeri P. Sequence stratigraphy and depositional setting of the Tiber Delta: integration of high resolution seismics, well-logs and archeological data. Journ. Sedim. Res. 1994. 64 B. 416-432.
Bellotti Р., Caputo C., Davoli L., Evangelista S., Pugliese F. Evolutionary Dynamics of the Crati River Delta (Italy). Proc. VI Int. Conf. MEDCOAST’03, 7-11 Oct. 2003. Ravenna, 2003. 1805-1816.
Bondesan М., Favero V., Vinals M.J. New evidence on the evolution of the Po delta coastal plain during the Holocene. Quatemary International. 1995. 29/30. 105-110.
Roveri М., Correggiati A, Asioli A., Trincardi F. Evoluzione dei sistemi deltizio e costieri in Adriatico settentrionale. Abs Volume GEOITALLA. 5-9 Sept. 1997. 1997. 4142.
Mikhailova M. Merphodynamics and morphometry of nontidal protruding river deltas. I.A H R. Symp. River. Coastal and Estuarine Morphodynamics, 6-10 Sept. 1999. Genova.
Piccazzo М., Firpo М., Ivaldi R., Arobba D. Il delta del Fiume Centa (Liguria occidentale): Un esempio di modificazione recente del clima e del paesaggio. Il Quaternario. 1994. 7. 293-298.
Ricci Lucchi F., Coltella A., Gabbianelli G., Rossi S., Normark W.R. The Crati submarine fan, Ionian Sea. Geo-Marine Letters. 1984. 3. 71-77.


Fig. 1. Scheme of distribution of the main Italian rivers
On four inset shows four types of deltas, described in the text. Percentages indicate the average slope of the underwater platforms near the mouth

Hydraulics is a topic in applied science and engineering dealing with the mechanical properties of liquids or fluids. At a very basic level, hydraulics is the liquid version of pneumatic. Fluid mechanics provides the theoretical foundation for hydraulics, which focuses on the engineering uses of fluid properties. In fluid power, hydraulics are used for the generation, control, and transmission of power by the use of pressurized liquids. Hydraulic topics range through some part of science and most of engineering modules, and cover concepts such as pipe flow, dam design, fluids and fluid control circuitry, pumps, turbines, hydro power, computational fluid dynamics, flow measurement, river channel behavior and erosion.Free surface hydraulics is the branch of hydraulics dealing with free surface flow, such as occurring in rivers, canals, lakes, estuaries and seas. Its sub-field open channel flow studies the flow in open channels.

Aquatic habitat assessment and river restoration design require geospatially explicit maps of hydraulic conditions. Diverse mechanistic ecohydraulic models compute spatially explicit depth and velocity results to evaluate habitat suitability spatially as a function of these abiotic conditions. This study compared depth and velocity results from two-dimensional (2D) and one-dimensional (1D) hydraulic models with algorithms that laterally discretize 1D velocity and interpolate depth and velocity spatially based on the Laplacian heat mapping approach.  These ‘conveyance distributed’ methods constitute ‘best 1D modeling practice’, and were compared to 2D results for the first time. The 1D and 2D models were applied to three morphologically distinct reaches (leveed, meandering, and anastomosing) for three flows (base, bankfull, and flood flows) of the partially regulated, gravel/cobble lower Yuba River in north-central California.  The test metrics were the coefficient of determination (R2) and the median absolute residual (|ε ̃ |).  These metrics quantified the incremental uncertainty 1D approximation incurs, results which make explicit cost-benefit processes of model selection possible.  Finally, velocity residual maps were analyzed to identify regions and processes where residuals were high, indicating divergence from the 1D assumptions. Paired data (1D-2D) fell between 0.94 ≥R2≥1.00 (R2mean=0.98 and R2median=0.99) for depth and median absolute residuals were all 3.8≤|ε ̃ |≤7.2% (i.e. 50% of residuals are approximately within ±1.7 to 3.6%).  Higher flows and lower gradient reaches had lower residuals and higher R2.  Velocity diverged more, particularly for base flow in anastomosing reaches (0.42<R2<0.58).  One-dimensional, conveyance distributed, assumptions performed better for other channel types, where 0.69 < R2 < 0.81 (R2mean=0.75 and R2median=0.77), with median absolute residuals between 9.6%> |ε ̃ |  >22.4% (i.e. ~±4.6 to ±11.2%), where |ε ̃ |mean =14.2% and |ε ̃ |median =13% (~±7.1 and 6.5%).  The conveyance distributed 1D velocity model performed best where the orthogonal flow assumptions obtained and where side channels did not transition from backwater to conveying area between flows.

In traditional writings about the Cistercians, the aspects relating to their hydrophilia are still little known. With this work, we intend to counteract this “hydraulic illiteracy” and show that the “white monks” also reached an indisputable competence in the area of survey and economic uses of water. Such competence was decisive for the scope, extended and fruitful, of their medieval communities. In order to work on proper health and hygiene conditions, the monasteries needed a solid and technically efficient hydrosystem, both in its shape and network, going from the water intake, transport and distribution within the cenobia, to the evacuation of household waste and rain water. This venture led to elaborated and strenuous works, some of them prior to the raising of community buildings. In the wide range of its tangible results, the history of medieval Cistercian monasteries is also a history of a long and close relationship between man and water. These are two topics of study as vast as meaningful in its religious, cultural and socio-economic context and relevance. The contents of these actions and objective reasons authorize, perhaps without exaggeration, the argument in favour of an intuitive “model” of Cistercian hydraulic architecture, which constitutes an open field of privileged study and discussion.

Memória apresentada por Custódio José Gomes de Vilas-Boas (1771-1809) à Academia Real das Ciências de Lisboa sobre a aplicação de engenhos hidráulicos (comportas e diferentes tipos de portas oscilatórias) para evitar o assoreamento dos cursos de água e melhorar a sua navegabilidade e o seu aproveitamento para irrigação.

Erosion of cohesive sediment is a complex phenomena and involves various factors comprising effective gravity, dry unit weight, sediment microstructure, particle size distribution, mineralogy, organic content and water chemical condition. The response of cohesive sediment to flow of water has received little attention. In light of this, a study is conducted in the hydraulics laboratory of National Institute of Technology, Kurukshetra. The objective of the study, besides filling up gaps in information, is to make an attempt to establish the effect of certain parameters of cohesive sediment on the erosion process in general and on the incipient motion in particular. The present paper, which is a part of the bigger study, compiles a review of the works by various researchers on the basis of parameters such as shear strength, consolidation pressure, plasticity index, clay content, salinity, compaction water content etc

This paper is intended as a contribution towards the development of better predictors of the
geometric characteristics of alternate bars. The specific objective of the paper is to introduce a new equation
for alternate bar length. It is assumed that the bars are formed under a steady and uniform flow; the bed is flat
at the beginning of the experiment; the stage of interest is that where bars have grown to their fully developed
state. The present equation is derived on the basis of dimensional considerations and all the data available to
the authors; bars produced under different regimes of the turbulent flow are treated separately. Accordingly,
the equation takes different forms depending on the flow regime. It is shown that the present equation produces
better estimates of bar length than previous equations for rough turbulent flows as well as flows in the transitional
regime of turbulent flow, with a marked improvement for the case of the transitional regime.

La situación de las ciudades en torno, a las riberas de los ríos, hace que deba existir un planeamiento, con el propósito de lograr el control de los ríos, de tal forma que no provoquen consecuencias como erosión y desbordamientos. En ese sentido, el presente trabajo tiene como objetivos específicos (a)Diseñar un sistema de defensa ribereña, que permita el control y la protección de las inundaciones y la erosión y (b)Plantear un plan de manejo y conservación de recursos naturales existentes en la cuenca del río Cuyocuyo. El proyecto de defensa ribereña, se localiza en la zona urbana de la ciudad y distrito del mismo nombre, Cuyocuyo, en la provincia de Sandia, departamento de Puno¸ a una latitud Sur 14°28´, longitud Oeste de 69°32´, la altitud de la localidad es de 3,401 msnm. La temperatura promedio anual es 10.8 °C; la precipitación pluvial media anual es de 820 mm; una máxima de 956 mm y una mínima de 550 mm. El presente estudio comprende los aspectos elementales: topografía de la investigación, evaluación de las áreas susceptibles a la erosión, hidrología del proyecto, hidráulica fluvial y erosión, estudio de geotecnia e impacto ambiental, complementado con los cálculos respectivos. Adicionalmente para la ejecución de los proyectos se tiene los costos unitarios, presupuestos, cronogramas de ejecución, especificaciones técnicas y planos. En los estudios de topografía se han seguidos varias etapas y éstas comprenden, los estudios de reconocimiento de campo, levantamiento topográfico o trazo en planta, nivelación o levantamiento altimétrico y cálculos de gabinete. La evaluación de áreas susceptibles a la erosión considera los aspectos relativos a los daños existentes y por presentarse como consecuencia de las acciones erosivas del río, esto fundamentalmente en la localidad de Cuyocuyo. Lo que permitió conocer el estado y proponer el cambio o rehabilitación del sistema de defensa ribereña.
La hidrología del proyecto desarrolla los temas para la obtención del caudal máximo de diseño. Estos básicamente son la climatología, los parámetros físicos de las cuencas, cálculo de máximas descargas. La Hidráulica fluvial y erosión permitió conocer la morfología del cauce en los tramos de interés, los parámetros para el inicio del movimiento de sólidos, los aspectos concernientes a la socavación de las estructuras, también las medidas de prevención y control de la erosión. Estas acciones fueron complementadas con los estudios geotecnia, canteras y fuentes de agua, asimismo el estudio de impacto ambiental, los cuales proporcionaron ideas claras para el diseño de las estructuras de defensa ribereña. El diseño del sistema de defensa ribereña tiene como propósito disminuir los riesgos de erosión en las márgenes y desbordamientos del río Cuyocuyo, para lo cual se ha tomado en cuenta los aspectos siguientes: la topografía, que ha aportado las mediciones en lo referente a la pendiente del río en el tramo en estudio; la hidrología, que proporcionó el gasto de diseño, que fue de 40 m3/s, para un tiempo de retorno de 50 años. Fue así que se han utilizado los criterios hidráulicos para la obtención de las dimensiones definitivas. Realizando los chequeos correspondientes, en lo que se refiere a la socavación general y la estabilidad de los muros.
El proyecto final consiste en el encauzamiento nuevo del río Cuyocuyo, con muros de contención, construído con materiales de la zona, tales como piedra pizarra y tierra orgánica, complementado con cemento. La longitud trazada total es de 1,120 metros. La zona de confluencia con el río Jilari, tiene un diseño con enrocado del fondo en su totalidad, ya que la fuerza de erosión del río Jilari, debido a su fuerte velocidad, es grande. Para el río Jilari, por estar sus estructuras, en menor grado de erosión y desgaste, se ha planteado la rehabilitación del fondo enrocado y de las caídas y pozas existentes, adicionalmente realizar el cambio total y enrocado del fondo en la zona de confluencia. La longitud total de la rehabilitación es de 250 metros. Es así que se ha calculado el presupuesto, teniendo en consideración los metrados y análisis de costos unitarios. Obteniéndose un total de S/. 1,260,750.70 (costo referido al 31/12/99).
A través del presente trabajo de investigación se ha llegado a las siguientes conclusiones y recomendaciones mas importantes:
• Que estando el sistema actual, en un estado precario, se plantea el cambio y rehabilitación con el diseño propuesto.
• Para lograr el manejo de la erosión a nivel de la cuenca, será fundamental iniciar un plan de contingencia contra la erosión en las partes altas de la cuenca de los ríos Jilari y Cuyocuyo.

A three-dimensional numerical model was applied to study the bed morphology and bedload transport of the junction of Ara and Kurau rivers in Perak in Malaysia. SSIIM2 a 3D k-ɜ turbulence CFD model with an adaptive, non-orthogonal and unstructured grid has been used for modeling the hydrodynamic of confluence. The numerical model was tested against field data from Ara-Kurau confluence. Satisfactory agreement was found between computed and measured bedload and bed elevation in the field. The study indicates that numerical models might become a useful tool for predicting the bedload transport rate and bed morphology changes in river confluences.

Sur le thème du Rhône, d’Orange à la mer, traité sur les sept derniers siècles (de 1300 à 2000), cet ouvrage est un apport à l’histoire du climat par deux historiens de l’environnement, Georges Pichard et Émeline Roucaute. L’étude hydrologique repose sur un millier d’événements (crues, étiages, glaces fluviales) qui mettent en valeur la violence de huit crises périodiques durant la période du Petit Âge Glaciaire. La première partie est consacrée à la dynamique fluviale à travers les inondations et les métamorphoses des lits fluviaux d’après les cartes anciennes. La deuxième partie étudie les pluies et les sécheresses, avec invasions de sauterelles et étiages exceptionnels, comme celui de 1639. Les grands hivers avec glaces flottantes et arrêtées y font également l’objet d’une étude statistique. Enfin, la troisième partie traite, par l’approche monographique, d’une dizaine d’événements hydroclimatiques extrêmes depuis le XVIe siècle dont l’étude s’en trouve ainsi renouvelée, notamment pour la crue centennale de 1856. L’ouvrage présente les principaux résultats d’une prospection dans les archives préparée de longue date par les recherches universitaires des auteurs. Les lecteurs retrouveront l’ensemble des sources d’archives de cette vaste enquête réunies dans une grande base de données mise en ligne(http://histrhone.cerege.fr/).

Laterites of Birbhum district are indentified as the ‘low-level laterites’ of ‘Rarh Plain’ of West Bengal and these are very much prone to severe soil erosion (mainly surface and sub-surface water erosion) in the monsoonal season (June - September.) Laterites and lateritic soils (locally named ‘Kankara’) of Caniozoic upland (adjoining areas of Rampurhat I block, Birbhum and Shikaripara block, Dumka- the study area), are the direct result of monsoonal wet-dry type of morpho-climatic processes and further laterisation of fluvial deposited materials (formation of surface duricrust) which was coming from Rajmahal Hills of eastern Chotanagpur Plateau (Jharkhand) in late Pleistocene. Such type of vermiform laterites is shaped and dissected by numerous gullies and ravines, giving birth of badland topography (locally named ‘Khoai’) of both degradation and aggradation processes. Before the soil conservation practices it is helpful if the assessment of soil erosion can be transformed into a statement of how fast soil is being eroded. The estimation of rate of annual soil loss is required in that case, because we must have to predict soil loss through effective models under a wide range of conditions. In this study the entire assessment is focused on the application Universal Soil Loss Equation (USLE) and Morgan, Morgan and Finney (MMF) methods in the soil loss estimation of sample slope segments, and relative comparison and suitability of both methods in the precise estimation of predicting soil loss.

The Orinoco River has the third largest discharge in the world, with an annual mean flow of 37 600 m 3 s −1 at its outlet to the Atlantic Ocean. Due to the presence of the Guiana Shield on the right bank, the lower reach of the Orinoco has a plan form characterized by contraction and expansion zones. Typical 1–1.5 km wide narrow reaches are followed by 7–8 km wide reaches. A complex pattern of bed aggradation and degradation processes takes place during the annual hydrological regime. A series of Acoustic Doppler Current Profiler (ADCP) transects were collected on an expansion channel in the Orinoco River, specifically over a fluvial island, representative of the lower Orinoco. In this study, temporal series of bathymetric cartography obtained by ADCP profiles combined with Differential Global Position System (DGPS) measurements (with dual-frequency), were used to recover the local displacement of bed forms in this island. The principal aims of this analysis were: (1) to understand ...

Low-grade metamorphics such as slates and schists tend to be subjected to relatively rapid surface deterioration by both weathering and fluvial wear. If the rate at which such processes are effective on these relatively soft rocks could be calibrated through their effects on surfaces of known ages, this would provide a possibility of estimating the age of petroglyphs on similar facies and in similar environments. An attempt of quantifying these processes is presented, using the petroglyph site of Siega Verde in western Spain as an example. A series of dated inscriptions occurring at a site of zoomorphic petroglyphs provides the data to plot rock surface deterioration against time. The involvement of numerous variables prevents this method from providing much precision, but it is adequate to offer indications of order of magnitude of age. The zoomorphs at Siega Verde have been attributed to the Upper Palaeolithic, but this method suggests that most of the site’s anthropic markings are under 200 years old. This finding is supported by several other factors, such as the degree of repatination of the supposedly Pleistocene petroglyphs, and the presence of a recent terrace predating these.

Studies regarding the influence of emergent vegetation on sediment transport are scarce and have mainly focused on flume conditions. To fill this gap and also meet the international need, we aimed to evaluate the influence of emergent vegetation (Echinodorus macrophyllus) on sediment transport of Capibaribe River, Brazil. Bedload and suspended sediment measurements were carried out using the US BLH 84 and US DH 48 samplers, respectively. Measurements of stem diameter, stem spacing and plant density were performed in conjunction with flow and sediment field measurements. Based on our results, 0.45 m s À 1 was the threshold of mean flow velocity supported by E. macrophyllus under field conditions. This value can be helpful for other rivers with gravel-bed river to armoured layer ratio (AR ¼D 50-surface)/D 50-subsurface ¼12.50) – natural conditions observed in Capibaribe River – or where the vegetation can provide positive effects, such as increase the bed stability, assist water restoration/ rehabilitation and decrease water turbidity. Our results can hopefully be used in engineering practice and ecosystem management. In general, both the drag coefficient and drag force varied inversely and directly with the mean flow velocity and vegetation density, respectively. The vegetation resistance force was inversely proportional to the bedload transport owing to the resistance caused by emergent vegetation. This finding was supported by the clear decoupling between nonvegetated and emergent vegetated conditions indicated by cluster analysis. The study results provided a reasonable understanding of the interaction between emergent vegetation, water flow and sediment transport in the Capibaribe River.

The success factor of a settling basin planning is the trap efficiency. In reality, it is difficult to create a detailed physical model of the sedimentation process. In a more detailed way, sedimentation process phenomena can be formulized by using mathematical equation, for this matter numerical simulation is selected to observe the settling basin performance.
A three-dimensional numerical model from SSIIMWin 1.1 is used to carry out this settling basin simulation of the Sapon weir planning. The trap efficiency of the sedimentation process is observed in two different situations: at the time when the settling basin is empty and when it is full. During the empty situation, the velocity and the initial trap efficiency process is measured. When the settling basin is full, inspection is performed to check whether the sedimentation trap process remains effective.
The trap efficiency depends on the characteristics of the inflowing sediment (fall velocity of the particle) and the water flow characteristic in the settling basin (flow velocity). Flow velocity simulation is demonstrated using a three-dimensional velocity vectors. Velocity distribution simulation indicates that the value of the horizontal flow velocity component from the upstream to the downstream (augmentation of x/b value) is decreased. The minimum horizontal flow velocity occurs in locations close to the bottom of the bed channel and increasing towards z/h to the surface water. Approaching the wall, the horizontal flow velocity is decreasing and reaches it’s maximum at y/B=0.5. The flow vertical velocity component indicates that approaching the bed channel, the vertical velocity is increasing. The lateral flow velocity component indicates a velocity increase at the horizontal expansion. A three-dimensional vortex occurs on the inlet of the settling basin, due to the vertical expansion. The vortex does not exist in the middle location of the settling basin. Another vortex occurs at the bottom of the channel approaching the downstream of the settling basin. The profile of sediment concentration distribution indicates an increase from the water surface to the bottom (bed channel). The sediment concentration is decreased in quantity to the downstream of the channel. The ratio of the incoming sediment that is deposited (trapped) and inflow the sediment mass entering a settling basin is 69,85 % for the upper 0.06 mm diameter particles. Volume changes of the pond, due to the deposit sediment volume, have lead to a decline in the trap efficiency process. When the volume of the sediments reaches a percentage of 71,84 % of the total pond volume, the settling basin is considered ineffective in performing sedimentation trap process.

Keywords : three-dimensional numerical simulation, trap efficiency, settling basin

Nindito, D.A., Istiarto, I. and Kironoto, B.A., 2008. Simulasi numeris tiga dimensi kantong lumpur bendung sapon. In Civil Engineering Forum Teknik Sipil (Vol. 18, No. 1, pp. 712-724).

Nindito, Dwi Anung, Istiarto Istiarto, and Bambang Agus Kironoto. "Simulasi numeris tiga dimensi kantong lumpur bendung sapon." Civil Engineering Forum Teknik Sipil. Vol. 18. No. 1. 2008.

Nindito, D. A., Istiarto, I., & Kironoto, B. A. (2008). Simulasi numeris tiga dimensi kantong lumpur bendung sapon. In Civil Engineering Forum Teknik Sipil (Vol. 18, No. 1, pp. 712-724).

Nindito, Dwi Anung, Istiarto Istiarto, and Bambang Agus Kironoto. "Simulasi numeris tiga dimensi kantong lumpur bendung sapon." In Civil Engineering Forum Teknik Sipil, vol. 18, no. 1, pp. 712-724. 2008.

Nindito DA, Istiarto I, Kironoto BA. Simulasi numeris tiga dimensi kantong lumpur bendung sapon. InCivil Engineering Forum Teknik Sipil 2008 (Vol. 18, No. 1, pp. 712-724).

Glaciers and snowpacks influence streamflow by altering the volume and timing of discharge. Without reliable data on baseline snow and ice volumes, properties and behaviour, initializing hydrological models for climate impact assessment is challenging. Two contrasting HySIM model builds were calibrated and validated against observed discharge data (2000-2008) assuming that snowmelt of the baseline permanent snowpack reserves in the high-elevation sub-catchment are either constrained (snowmelt is limited to the seasonal snow accumulation) or unconstrained (snowmelt is only energy-limited). We then applied both models within a scenario-neutral framework to develop impact response surface of hydrological response to future changes in annual temperature and precipitation. Both models had similar baseline model performance (NSE of 0.69-0.70 in calibration and 0.64-0.66 in validation), but the impact response surfaces differ in the magnitude and (for some combinations) direction of model response to climate change at low (Q10) and high (Q90) daily flows. The implications of historical data inadequacies in snowpack characterization for assessing the impacts of climate change and the associated timing of hydrological tipping points are discussed.

На основе анализа картографических данных и археологических сведений восстановлена история формирования дельты Тибра приблизительно за 2.5 тыс.лет. Показано, что особенности гидрологоморфологических процессов в устье Тибра в основном связаны с повышением уровня моря, естественными и антропогенными изменениями стока воды и наносов. Впервые рассмотрен баланс наносов в устье Тибра.

Watermills (grain mills, waulk mills, olive mills, sawmills and threshing machines) operated in the Basilicata Region from the Roman Period until the early decades of the twentieth century, representing an important feature of waterways that is today almost totally forgotten. Using documentary sources, ancient maps and field survey it is possible to catalogue and identify the location of these ancient hydraulic structures. Watermills were usually placed far enough away from the river to avoid inundation during floods, and near natural knickpoints or artificial steps in the river long profile that were created by mill engineers. Mill construction often had significant impacts on a river morphology, because it was necessary to divert the river discharge towards the mill wheel, to drive the grain-grinding mechanism. Watermill typological variations have been examined in relation to variations in river pattern to assess the ways in which the hydrographic and hydrological settings of the Basilicata Region have affected mill siting and operation. Most Basilicata watermills were built with a horizontal water-wheel and a tower. The characteristics of the tower and the associated hydraulic structures varied according to the environmental setting. Finally, mill positions define also the locations on the river system that have already been used to exploit hydraulic power and thus could be useful for future use in the micro-hydroelectric sector

The present geomorphic study analyzes the morphometric anomalies of the lateritic badlands (West Bengal, India) to understand the erosion intensity, triggering factors and landscape evolution using the ALOS AW3D30 DEM and quantitative techniques of various hydro-geomorphic processes (viz., basin morphometry, rainfall-runoff simulation, geomorphic threshold, erosion indices, sediment yield, SPI, and STI etc.). The GIS-based analysis reflects that there is the requitement of minimum drainage area (i.e. 55.71–349.01 m2) to maintain one metre of gully channel in the basins which have the network density of 2.86–13.76 km km−2. The critical slope (i.e. geomorphic threshold) of badland terrain varies from 0.0222 to 0.0407 metre metre−1, having dominance of overland flow erosion to initiate gully heads. The basin-wise SCS-CN and USLE coupling estimates that within the daily rainfall range of 11.41–66.41 mm day−1, the potential sediment yield of gully basins varies from 2.15 to 9.10 t ha−1. The SL index (i.e. 0.81–47.32 m) diagram reflects the beats of gully energy profile due to stream erosion enhancement, slope steepness, resistance of underlying lithologies and active tectonics. Hypsometric integral values of the gully basins, ranging from 0.4 to 0.6, emphasize a low entropy-based fluvial system and development of mature-youthful landform stage. The evolutionary stages of badlands are explained here by the connectivity model and hillslope – gully – river coupling system, showing a quasi-equilibrium to complex stage of landscape development at present.