Minor Distributary Research Articles

Performance Evaluation and Water Availability of Canal Irrigation Scheme in Punjab Pakistan

The supply of surface water by century-old infrastructure causes substantial water loss and triggers huge abstractions of groundwater, resulting in low irrigation efficiency. We evaluated the irrigation performance (application and conveyance efficiencies) and water availability (supply-demand) from the field to the Mungi Distributary canal level in Punjab, Pakistan. Between April–September 2019 and 2020, we monitored water delivery in the canal network, soil moisture content in cotton fields, and the canal and groundwater quality. The crops’ actual evapotranspiration was estimated using the AquaCrop model. We found conveyance efficiencies >90% for minor distributaries, 70–89% for watercourses, and ~75% for field ditches per kilometer. Field application efficiency was >90% for drip and ~35% for flood basin, whereas for raised-bed furrow, conventional furrow, and ridge-furrow irrigation methods, it varied between 44% and 83%. The deficits of canal water supply versus demand for cotton fields ranged from 45% to 73%, whereas the Mungi Distributary canal water showed a 68.6% and 19.8% shortfall in the April–September and October–March seasons of 2018/2019, respectively. The study suggests prioritizing improvements to field water application rather than canals with better water quality; additionally, surplus water from the Mungi canal in November and December could be stored for later use.

Design of Canal by Closing out Debits of Current Canal System

Canals are natural streams channels, or manmade streams, for water movement, or to support water movement, or to support water transport vehicles. Fundamental capacity of waterway is to convey water from water assets for irrigation or domestic utilization of water. The whole water movement framework for water system, containing the fundamental channel, branch waterways, major and minor distributaries. Water is a valuable asset. It is needed by human in doing distinctive day by day exercises. This valuable asset while going through the canal is lost from the channels through leakage from the sides and lower part of the canals and by evaporation from the top water surface of the canals. This project aims at modelling a canal section using HEC-RAS conducting flow analysis such that there is no silting and scouring in the canal. HEC-RAS is a computer program that help model the hydraulics of water flow through natural rivers and artificial or natural channels. The objective is to estimate evaporation and seepage losses and suggest necessary remedies in order to avoid these water debits from the canals.

Architecture and preservation in the fluvial to marine transition zone of a mixed‐process humid‐tropical delta: Middle Miocene Lambir Formation, Baram Delta Province, north‐west Borneo

AbstractThe interaction of river and marine processes in the fluvial to marine transition zone fundamentally impacts delta plain morphology and sedimentary dynamics. This study aims to improve existing models of the facies distribution, stratigraphic architecture and preservation in the fluvial to marine transition zone of mixed‐process deltas, using a comprehensive sedimentological and stratigraphic dataset from the Middle Miocene Lambir Formation, Baram Delta Province, north‐west Borneo. Eleven facies associations are identified and interpreted to preserve the interaction of fluvial and marine processes in a mixed‐energy delta, where fluvial, wave and tidal processes display spatially and temporally variable interactions. Stratigraphic successions in axial areas associated with active distributary channels are sandstone‐rich, comprising fluvial‐dominated and wave‐dominated units. Successions in lateral areas, which lack active distributary channels, are mudstone‐rich, comprising fluvial‐dominated, tide‐dominated and wave‐dominated units, including mangrove swamps. Widespread mudstone preservation in axial and lateral areas suggests well‐developed turbidity maximum zones, a consequence of high suspended‐sediment concentrations resulting from tropical weathering of a mudstone‐rich hinterland. Within the fluvial to marine transition zone of distributary channels, interpreted proximal–distal sedimentological and stratigraphic trends suggest: (i) a proximal fluvial‐dominated, tide‐influenced subzone; (ii) a distal fluvial‐dominated to wave‐dominated subzone; and (iii) a conspicuously absent tide‐dominated subzone. Lateral areas preserve a more diverse spectrum of facies and stratigraphic elements reflecting combined storm, tidal and subordinate river processes. During coupled storm and river floods, fluvial processes dominated the fluvial to marine transition zone along major and minor distributary channels and channel mouths, causing significant overprinting of preceding interflood deposits. Despite interpreted fluvial–tidal channel units and mangrove influence implying tidal processes, there is a paucity of unequivocal tidal indicators (for example, cyclical heterolithic layering). This suggests that process preservation in the fluvial to marine transition zone preserved in the Lambir Formation primarily records episodic (flashy) river discharge, river flood and storm overprinting of tidal processes, and possible backwater dynamics.

Implications of tidally-varying bed stress and intermittent estuarine stratification on fine-sediment dynamics through the Mekong’s tidal river to estuarine reach

River gauging stations are often located upriver of tidal propagation where sediment transport processes and storage are impacted by widely varying ratios of marine to freshwater influence. These impacts are not yet thoroughly understood. Therefore, sediment fluxes measured at these stations may not be suitable for predicting changes to coastal morphology. To characterize sediment transport dynamics in this understudied zone, flow velocity, salinity, and suspended-sediment properties (concentration, size, and settling velocity) were measured within the tidal Sông Hậu distributary of the lower Mekong River, Vietnam. Fine-sediment aggregation, settling, and trapping rates were promoted by seasonal and tidal fluctuations in near-bed shear stress as well as the intermittent presence of a salt wedge and estuary turbidity maximum. Beginning in the tidal river, fine-grained particles were aggregated in freshwater. Then, in the interface zone between the tidal river and estuary, impeded near-bed shear stress and particle flux convergence promoted settling and trapping. Finally, in the estuary, sediment retention was further encouraged by stratification and estuarine circulation which protected the bed against particle resuspension and enhanced particle aggregation. These patterns promote mud export (~1.7ts−1) from the entire study area in the high-discharge season when fluvial processes dominate and mud import (~0.25ts−1) into the estuary and interface zone in the low-discharge season when estuarine processes dominate. Within the lower region of the distributaries, morphological change in the form of channel abandonment was found to be promoted within minor distributaries by feedbacks between channel depth, vertical mixing, and aggregate trapping. In effect, this field study sheds light on the sediment trapping capabilities of the tidal river – estuary interface zone, a relatively understudied region upstream of where traditional concepts place sites of deposition, and predicts how fine-sediment dynamics and morphology of large tropical deltas such as the Mekong will respond to changing fluvial and marine influences in the future.

Recognition criteria, characteristics and implications of the fluvial to marine transition zone in ancient deltaic deposits (Lajas Formation, Argentina)

AbstractThe seaward end of modern rivers is characterized by the interactions of marine and fluvial processes, a tract known as the fluvial to marine transition zone, which varies between systems due to the relative strength of these processes. To understand how fluvial and tidal process interactions and the fluvial to marine transition zone are preserved in the rock record, large‐scale outcrops of deltaic deposits of the Middle Jurassic Lajas Formation (Neuquén Basin, Argentina) have been investigated. Fluvial–tidal indicators consist of cyclically distributed carbonaceous drapes in unidirectional, seaward‐oriented cross‐stratifications, which are interpreted as the result of tidal modulation of the fluvial current in the inner part of the fluvial to marine transition zone. Heterolithic deposits with decimetre‐scale interbedding of coarser‐grained and finer‐grained facies with mixed fluvial and tidal affinities are interpreted to indicate fluvial discharge fluctuations (seasonality) and subordinate tidal influence. Many other potential tidal indicators are argued to be the result of fluvial–tidal interactions with overall fluvial dominance or of purely fluvial processes. No purely tidal or tide‐dominated facies were recognized in the studied deposits. Moreover, fluvial–tidal features are found mainly in deposits interpreted as interflood (forming during low river stage) in distal (delta front) or off‐axis (interdistributary) parts of the system. Along major channel axes, the interpreted fluvial to marine transition zone is mainly represented by the fluvial‐dominated section, whereas little or no tide‐dominated section is identified. The system is interpreted to have been hyposynchronous with a poorly developed turbidity maximum. These conditions and the architectural elements described, including major and minor distributary channels, terminal distributary channels, mouth bars and crevasse mouth bars, are consistent with an interpretation of a fluvial‐dominated, tide‐influenced delta system and with an estimated short backwater length and inferred microtidal conditions. The improved identification of process interactions, and their preservation in ancient fluvial to marine transition zones, is fundamental to refining interpretations of ancient deltaic successions.

Prediction of channel connectivity and fluvial style in the flood-basin successions of the Upper Permian Rangal coal measures (Queensland)

Predicting the presence and connectivity of reservoir-quality facies in otherwise mud-prone fluvial overbank successions is important because such sand bodies can potentially provide connectivity between larger neighboring sand bodies. This article addresses minor channelized fluvial elements (crevasse-splay and distributary channels) and attempts to predict the connectivity between such sand bodies in two interseam packages of the Upper Permian Rangal Coal Measures of northeastern Australia. Channel-body percent as measured in well logs was 2% in the upper (Aries-Castor) interseam and 17% in the lower (Castor-Pollux) interseam. Well spacing were too great to allow accurate correlation of channel bodies. The Ob River, Siberia, was used as a modern analog to supply planform geometric measurements of splay and distributary channels so that stochastic modeling of channel bodies was possible. The resulting models demonstrated that (1) channel-body connectivity is more uniform between minor distributary channels than between crevasse-splay channels; (2) relatively good connectivity is seen in proximal positions in splays but decreases distally from the source as channel elements diverge; and (3) connectivity tends to be greater down the axis of splays, with more isolated channel bodies occurring at the margins.

Middle Holocene Avulsion-Belt Deposits in the Central Rhine-Meuse Delta, The Netherlands

Abstract The Schoonrewoerd fluvial system in the central Rhine–Meuse delta was active as a Rhine distributary between 3900 and 3800 14C years BP. Based on planform patterns, cross-sectional facies architecture, reconstructed paleodischarge, and its short period of activity, the Schoonrewoerd fluvial system is interpreted to represent a failed avulsion. The Schoonrewoerd system consists of a complex of (ribbon) channel sand bodies encased in a lens of clayey deposits, and it can be traced for more than 35 km in a downstream direction. Prominent features of the system are longitudinal facies-architecture change, with channel sand-body width/thickness ratio decreasing downstream from ~ 40 to 5, and high lateral facies variability. Multiple anastomosing sand bodies occur in its upper and middle reaches. Paleodischarge reconstruction indicates that the Schoonrewoerd system was only a minor distributary within the Rhine–Meuse deltaic system. Specific stream power in the lower reach is estimated to have been low (0.5 to 1.8 W/m2). The short period of activity of the Schoonrewoerd system suggests that very high floodplain sedimentation rates were associated with the avulsion process, with the formation of meters-thick fine-grained sedimentary successions in ~ 100 years. The facies architecture of the short-lived Schoonrewoerd system is interpreted to reflect the first stages of avulsion (broadly analogous to the modern Saskatchewan River avulsion in Canada; Smith et al. 1989, Sedimentology, v. 36, p. 1–23), having escaped from later erosion by a more mature channel belt. Many other systems (often partly eroded) with similar facies architecture exist in the west-central Rhine–Meuse delta, suggesting that are a major component of the Holocene delta deposits. The facies-architecture model of the Schoonrewoerd avulsion-belt deposits presented in this paper may provide clues for the interpretation of fine-grained sedimentary successions in ancient fluviodeltaic deposits.

Late Pleistocene fluvial sedimentary facies, the Dhadhar River basin, Western India

The Late Pleistocene fluvial succession is exposed as 18–20 m high incised vertical cliffs all along the Dhadhar River basin in western India. The major fluvial sedimentary facies of the Late Pleistocene deposits in the Dhadhar River basin have preserved evidence of palaeodrainage and could provide an important link between the sub-humid Narmada basin in the south and the semi-arid Mahi basin in the north. The sedimentary facies documented include overbank fines, which are associated with crevasse splays. Fine grained overbank sediments are interpreted as having formed by sheet flow of sediments over the banks of minor distributary channels during the flood stage. The overlying thinly stratified fluvial sands and silts, at the top of the exposed sediment succession show a thin cap of aeolian sediments suggesting less intense aeolian activity than that observed in Sabarmati, Mahi and Orsang basins, though a significant reduction in fluvial activity is suggested during the arid phase of the LGM. However, the river may still have been perennial assuming that it retained the larger part of the catchment.

Low sinuosity and meandering bedload rivers of the Okavango Fan: channel confinement by vegetated levées without fine sediment

The river systems of the Okavango Fan negate present fluviological perceptions that fluvial geometry is primarily dependent upon the type of sediment load being carried by the river. In northwest Botswana, meandering and low sinuosity rivers, both of which may show anastomosis, are distinctly bedload in character. This is mainly because of a restricted source of clastic sediment, consisting of aeolian sand from the Tertiary to Recent Kalahari Basin. All that seems to be required, therefore, to control low sinuosity and meandering geometries is adequate confinement of channels. In the study examples this is provided by heavily vegetated levées comprising peat, formed from and colonised by a Cyperus papyrus dominated flora: fine sediment plays almost no role in the confinement process.Active and abandoned examples of low sinuosity river channels were studied. An inversion of topography develops in the latter, caused by the low survival probability of metres thick peat levées. Desiccation and burning of peat ultimately form a degraded ash layer only tens of centimetres thick. The channel sand then stands as a ridge rising above the surrounding fan surface. In both examples studied, no crevasse splays occur, but hippopotami trails breach the levées to form minor distributary channels which become filled with sand. The sand ultimately grades backwards to plug the breach.Meander belts are also developed, particularly in the upper fan and entry corridor. Cut banks incise into the sand substrate and scroll bar topographies can be discerned beneath their peat cover. Fine sediment plays no role in the confinement of these channels, which are maintained by peat levées similar to those encountered in the low sinuosity river channels. The recognition of these bedload low sinuosity and meandering river channels now completes the matrix, whereby any geometry of river channel can be developed in bedload, mixed load and suspended load rivers.Important aspects of the modern channels for the study of ancient river systems are (1) the confining effect of peat levées which have low preservation potential geologically, and (2) in helping to explain river systems which show contradictory evidence of semi-arid and more humid climatic conditions. The latter may be explained as perennial rivers entering an otherwise semi-arid climatic regime from a distant source, which provide a shifting “more humid” overprint to the inherent environmental characteristics.

Quantitative Outcrop Analysis of Coastal-Plain Sequences from Eastern Kentucky: Example of High-Quality Data Input to Three-Dimensional Reservoir Modeling: ABSTRACT

An integral aspect of inter-well scale reservoir geological modeling research is the collection of high-quality data on sand-body geometries and facies architectures. Such studies are aided by exceptionally large outcrops in structurally undisturbed areas. The Pocahontas foreland basin of eastern Kentucky contains well-exposed fluvial-deltaic sequences with negligible tectonic deformation in the basin fill. Coastal-plain sequences are characterized by major mouth bars; stacked, multilateral, low and high-sinuosity distributary channel systems; and a series of minor distributary channel sandstones/coarsening-upward crevasse delta sequences. Large (up to 500 m x 4 km) roadcut exposures covering a total of some 250 km of highway, coupled with exact coal seam correlation, have allowed three-dimensional mapping of different genetic sandbody geometries, creating a reliable data base for reservoir geological modeling in similar depositional systems. Outcrop correlation panels published by the University of Kentucky have been interpreted in terms of reservoir elements and digitized into a pixel-based data base. The digitized panels were analyzed in terms of horizontal and vertical transitions between reservoir elements. These data allow probabilities to be assigned to both vertical and lateral organization of the various reservoir elements. Lateral transition matrices have been used to quantify, for example, the probability of an active channel-fillmore » sandstone being in connection with other reservoir sand bodies. Inclusion of such probabilities in probabilistic reservoir models will maximize the accuracy of reservoir configurations predicted from well data alone.« less

Architecture of the Castissent fluvial sheet sandstones, Eocene, South Pyrenees, Spain

ABSTRACTThe Castissent Formation represents a phase of strong fluvial progradation within the fluvio‐deltaic Montanyana Group, probably enhanced by the late Ypresian sea‐level fall. The structural setting is characterized by the emplacement of the South Pyrenean nappes. The major architectural feature of the Formation is the superposition of three multilateral and multistorey sheet sandstone complexes (A, B and C), interbedded in finer floodplain deposits and dark‐grey mudstones of brackish transitional origin. The structure of the sheet sandstone complexes is exemplified by the detailed analysis of the lower sheet sandstone complex (A), 25 m thick, 6 km wide and exposed over 25 km of its length. Three types of channel‐fill sandstones serve as components: (1) lenticular‐bedded bodies, interpreted as braided stream deposits, (2) lateral accretion‐bedded bodies, intepreted as meandering stream deposits, and (3) ribbons, originating from laterally stable and short‐lived offshoot or crevasse channels. By coalescence and/or stacking of these channel‐fill types, higher‐order architectural units (A1, A2, A3) have been formed that together build the sheet sandstone complex. On the basis of downstream variation in proportion and geometrical relation between the channel‐fill components, three depositional zones have been differentiated within the fluvial system. Each zone is characterized by specific architectural processes: (1) alternation of minor aggradational‐degradational cycles in the proximal valley, (2) generation of new alluvial belts in the intermediate nodal avulsion zone, and (3) successive random avulsion processes with development of semipermanent crevasse channels or minor distributaries in the distal distributive zone. The sedimentation of the Castissent Formation was structurally controlled by an interplay of vertical basement movement due to thrust stacking in the hinterland and surficial thrust displacement to the foreland resulting in alternating southward and northward shift of the fluvial system.

Reservoir Characteristics and Depositional Environments of Upper Strawn Series (Pennsylvanian) Capps Limestone and Fry Sandstone Core, Lake Abilene Field, Taylor County, Texas: ABSTRACT

Detailed geologic and special core analyses were conducted on cores from the McIver, Inc., Sears 9 well, Lake Abilene field, Taylor County, Texas. The total Fry-Capps primary production from the Sears lease was approximately 473,000 bbl of oil and 737 mmcf of gas. Primary recovery was 109 bbl/ac-ft. Waterflood susceptibility tests indicate a 39% residual oil saturation after flooding and a 61% original mobile oil saturation. Secondary recovery should equal or exceed primary production. The Fry sandstone is a medium to fine-grained, well-sorted, quartz- and calcite-cemented quartzarenite, fining upward into a sublitharenite. Scanning electron microscopy and x-ray diffraction reveal 1-3% authigenic clays (kaolinite, illite, and chlorite) lining the pores. Horizontal permeability averages 473 md, and the weighted-average porosity is 14%. Pore diameters range from 0.05 to 0.3 mm and average 0.1 mm. Primary porosity of 30% of more has been greatly reduced by quartz overgrowths and poikilotopic calcite. Much of the current porosity is secondary. The Capps Limestone is wackestone and packstone. The average horizontal permeability is 199 md, and the weighted-average porosity is 10.5%. Pore types are predominantly moldic and vuggy. Pore diameters range from 0.05 to 2 mm and average 0.1-0.3 mm. The Fry sandstone in this coremore » was deposited as a minor distributary channel on the distal end of a westward or northwestward prograding cratonic bayhead delta. The Capps is a thin limestone that transgressed east over the abandoned and subsiding Fry sand channel.« less

Fluvial channel and overbank deposits from the Westphalian of the Durham coalfield, NE England

ABSTRACTThe Westphalian (Upper Carboniferous) Coal Measures of the Durham coalfield in NE England were deposited in lower and upper delta plain environments. Distributary channels crossed the plain and were separated by shallow, interdistributary lakes and bays. Detailed observation of three‐dimensional (3‐D) opencast (surface) mine exposures, in collaboration with subsurface borehole analysis, has revealed the existence of five varieties of channel deposits and two associated overbank facies within the Durham Coal Measures.Major distributary channels were the major avenues of sediment transport across the Coal Measures plain, were variably sinuous, mostly 1–2 km wide and deposited elongate belts of sand mostly up to 5 km wide. Proximal, major crevasse splay channels formed by the breaching of major channel banks during flood events, were straight, sand‐filled and up to 400 m wide. Minor distributary channels formed by the sustained operation of such crevasses, varied from straight to highly sinuous, and deposited ‘shoestring’ sand/mud belts up to a few hundred metres wide. Minor crevasse channels, generally straight and up to 50 m wide, were formed through bank breaching of minor, and in a few cases major, distributaries. Distal feeder channels formed down‐palaeocurrent extensions of minor distributaries which supplied interdistributary minor delta subsystems, were generally straight and up to 200 m wide.Of the two types of channel overbank (levee) deposits recognized, one, comprising thinly interbedded fine‐grained sandstone and siltstone/claystone, is mostly, though not exclusively, associated with major distributary channels. The other, consisting of ‘massive’ siltstones with regularly spaced, thin claystone bands, is uniquely developed at the margins of minor distributary channels.The lower part of the Westphalian A succession in the northern Pennines records a change in the depositional environment upwards from a lower to upper delta plain. Through this transition, major channel deposits show evidence of having evolved from being of dominantly low sinuosity to being more variable in morphology. Channel sedimentation was profoundly influenced by regular, possibly seasonal, variations in flow stage and sediment load.

Deltaic Sedimentation, South Platte Formation (Lower Cretaceous), Morrison Area, Jefferson County, Colorado: ABSTRACT

Previous workers have delineated deltaic sedimentation from a western source within the South Platte Formation. Outcrop studies in the Morrison-Deer Creek area provide a model for sedimentation within the region of maximum channel development of the South Platte Formation. The total thickness of the South Platte Formation is 170 to 245 ft. The sequence at the base of the South Platte represents marginal marine deposits and alternate fresh to marine interdistributary bays. Ten to 20-ft sandstones, approximately 300 ft wide are active or partly active fills of minor distributary channels, or crevasse-splay channels associated with delta-plain sedimentation of a major delta lobe. Major multiple distributary channels formed as the delta End_Page 914------------------------------ lobes developed and prograded. These lenticular sandstone units, such as the Kassler sandstone are 20-40 ft deep and 1,500-2,800 ft wide. Active channel fill is 50 to 90%. Similar major channels are developed within the upper part and at the top of the South Platte (J sandstone interval). One channel at Turkey Creek is oil saturated. Minor penecontemporaneous faulting within the South Platte Formation produced offsets of 0.5 to 7 ft, with reconstructed strikes of the faults being perpendicular to and parallel with major channel trends. The faults may have been caused by rapid sedimentation and compaction or by minor offsets above basement-fault systems. End_of_Article - Last_Page 915------------

Nile Delta: The Defunct Pelusiac Branch Identified

The course of the ancient Pelusiac branch of the Nile River has been traced on a deltaic plain east of the Suez Canal, between the El Baqar Canal and Tell el Farama (ancient Pelusium). Two minor distributaries branched northward. The critical stage in the process of the silting up of the lower reaches of the Pelusiac branch, due to prograding beach accretion, occurred around A.D. 25. Ancient ruins in the area are closely associated with the courses.