Sediment Production Rates Research Articles

Study on Soil Stabilization and Slope Protection Effects of Different Plants on Fully Weathered Granite Backfill Slopes

The slope erosion in the distribution area of completely weathered granite is often relatively severe, causing serious ecological damage and property loss. Ecological restoration is the most effective means of soil erosion control. Taking completely weathered granite backfill soil as the research object, two types of slope protection plants, Vetiver grass and Pennisetum hydridum, were selected. We analyzed these two herbaceous plants’ soil reinforcement and slope protection effects through artificial planting experiments, indoor simulated rainfall experiments, and direct shear tests. The test results showed that the runoff and sediment production rates of the two herbaceous plant slopes were significantly lower than those of the bare slope, with the order of bare slope > Vetiver grass slope > Pennisetum hydridum slope. Compared with the bare slope, the cumulative sediment production of the Vetiver grass slope at 60 min decreased by 56.73–60.09%, and the Pennisetum hydridum slope decreased by 75.97–78.45%. The indoor direct shear test results showed that soil cohesion decreases with increasing water content. As the root content of Vetiver grass roots increases, soil cohesion first increases and then decreases, reaching a maximum value when the root content is 1.44%. As the root content of Pennisetum hydridum increases, soil cohesion increases. The internal friction angle increases slightly with increasing water content, while the root content does not significantly affect the internal friction angle. Therefore, the shear strength of soil decreases when the water content increases. The shear strength of the Vetiver grass root-soil composite reaches a peak at a root content of 1.44%, while the shear strength of the giant king grass root-soil composite increases as the root content increases. At the same root content, the shear strength of the Vetiver grass root-soil composite is slightly higher than that of giant king grass. The reinforcement effect of roots on shallow soil is better than on deep soil. Both herbaceous plants have an excellent soil-fixing and slope-protecting impact on the fully weathered granite backfill slope. Pennisetum hydridum’s soil and water conservation effect is significantly better than that of the Vetiver grass. In contrast, Vetiver grass roots slightly outperform Pennisetum hydridum in enhancing the shear strength of the soil. The research results can provide a theoretical basis for the vegetation slope protection treatment of fully weathered granite backfill slopes.

Effects of check dam construction on sediment production and topographic changes in a gully in the Loess Plateau: A rainfall simulation experiment

AbstractTo maintain a reasonable sediment regulation system in the Loess Plateau, it is critical to determine the effects of check dam construction on sediment production and topographic changes. An indoor simulation experiment was conducted to investigate sediment production at the outlet section of the gully and micro‐topographic changes within the channel before and after dam construction. The results showed that check dam significantly affected the run‐off and sediment transport processes in the watershed. Specifically, the cross‐sectional morphology index (η) and the width‐depth ratio increased by 10.23% and 40.44%, respectively, while sediment content and particle size decreased by 39.29% and 18.58%, respectively. Additionally, the relative importance of section parameters and micro‐topographic parameters that affect sediment production rate and particle size was ranked using the random forest algorithm. The roughness after check dam construction was identified as a relatively important topographic factor affecting sediment production and particle selection by erosion. These findings provide valuable information for future check dam construction and development in the Loess Plateau region.

Giant sediment-wave field and supercritical flows in a distally steepened ramp, Fort Payne Formation (Lower Mississippian), Kentucky–Tennessee, U.S.A.

ABSTRACT Sediment waves are common in confined to unconfined settings on modern marine slopes and basin floors worldwide. Their morphology and stratal patterns show that many of them migrate upslope and upflow, a characteristic thought to record Froude-supercritical flow conditions associated with sediment gravity flows and density cascades. Few sediment waves of this type have been observed in the ancient rock record. This study reports the discovery of a giant (> 20,000 km2) sediment-wave field in Lower Mississippian carbonates and shales of the Fort Payne Formation in Tennessee and Kentucky, U.S.A. Sediment waves are present in the clinothem slopes and basin floor of a distally steepened ramp as seismic-scale bedforms ranging from 100 to 700 m long and 15 to 50 m high. Dominant facies include crinoidal shales, packstones, and rudstones. Many of the beds are sharp-based and graded, indicating sediment-gravity-flow deposition. Upslope-inclined rudstones (backsets) and wavy beds with upflow and downflow laminae are common and indicate supercritical flow conditions. These observations and interpretations are in stark contrast to previous interpretations of crinoidal bioherms and Waulsortian-type mounds. Basin physiography, a cool-water heterozoan carbonate factory and coastal upwelling were key factors in establishing a rapidly prograding ramp characterized by high rates of sediment production and basinward shedding. Sediment gravity flows and density cascades transported crinoidal grains downslope and entrained crinoids that inhabited the slope. Flows frequently reached Fr-supercritical flow conditions that led to the formation of sediment waves similar to those on modern marine slopes. This sediment-wave field is one of the first to be documented in the ancient rock record, and its extent is enormous. The near absence of other reported ancient examples must be due to misinterpretation (mounds, slumps) and the problem of observational scale and resolution. Sediment waves are often larger than outcrops. Lack of recognition of sediment waves in subsurface seismic sections is probably due to misinterpretation and insufficient resolution. Perhaps this study demonstrates the need for revisiting and updating existing facies models of carbonate-sediment transport and depositional processes across slopes and basin floors.

Fine‐grained sediment production by endolithic sponges on Caribbean coral reefs

AbstractEndolithic sponges are key players in carbonate cycling on coral reef systems. While their bioerosion of reef framework is relatively well studied, their role in biogenic sediment generation is poorly understood. In this study, the sedimentary attributes and production rates of eight Caribbean endolithic sponge species were characterized. The findings revealed notable species‐specific variations in sediment production rates (range: 1.0–6.3 kg CaCO3 m−2 yr−1), alongside consistency in sediment characteristics (modal sizes ranging from 39 to 48 μm). The species‐specific rates were used to explore reef‐scale variations in sponge‐derived sediment generation across 50 reef sites in the Mexican Caribbean. Significant between‐site variability was observed, with estimated annual sediment production ranging from < 0.01 to 0.84 kg m−2 of reef. Production was primarily driven by sponge abundance, with discernible spatial variations in the contributions of different species, which could be related to variability in local environmental conditions. The rapidity at which these sediment producers can utilize dead coral substrates, coupled with their positive response to the changing marine environment, highlights the growing importance of these sponges in modern degraded Caribbean reef systems.

Meta‐Study of Carbonate Sediment Delivery Rates to Indo‐Pacific Coral Reef Islands

AbstractCoral reef islands are amongst the most vulnerable environments to sea‐level rise (SLR). Recent physical and numerical modeling studies have demonstrated that overwash processes may enable reef islands to keep up with SLR through island accretion. Sediment supply to these islands from the surrounding reef system is critical in understanding their morphodynamic adjustments, but is poorly constrained due to insufficient knowledge about sediment delivery rates. This paper provides the first estimation of sediment delivery rates to coral reef islands. Analysis of topographic and geochronological data from 28 coral reef islands indicates an average rate of sediment delivery of c. 0.1 m3 m−1 yr−1, but with substantial inter‐island variability. Comparison with carbonate sediment production rates from census‐based studies suggests that this represents one quarter of the amount of sediment produced on the reef platform. Results of this study are useful in future modeling studies for predicting morphodynamic adjustments of coral reef islands to SLR.

Reef island evolution in a turbid‐water coral reef province of the Indo‐Pacific

AbstractCoral reef islands are vulnerable landforms to environmental change. Constructed of largely unconsolidated reef‐derived sediments, they are highly sensitive to variations in metocean boundary conditions, raising global concern about their future resilience and stability in the face of increased natural hazards, sea‐level rise and anthropogenic climate change. This study examines the evolution of an inshore turbid reef island from the southern Pilbara region of Western Australia (Indo‐Pacific) using detailed analyses of island chronostratigraphy (composition, texture) and geochronology (21 in‐situ radiometric dates) from Eva Island. Downcore, composition of island‐grade (reef‐derived) sediments were homogenous, dominated by molluscan (37%–42%) and coral (32%–37%) constituents. The 14C radiometric dating of island sediments, beachrock and coral microatolls identified five stages of island formation across changing sea‐level regimes over the mid to late Holocene: (1) limestone platform accretion at ca 6,000 cal yr BP, coinciding with reef decline or ‘give‐up’ on neighbouring Exmouth Gulf reefs; (2) sand cay (i.e. core) initiation and vertical aggregation at ca 5,000 cal yr BP during the point of sea‐level regression to current levels; (3) major accretion and lateral progradation of the island between 3,500 cal yr BP and 2,500 cal yr BP including the modification of island shorelines through alongshore reworking of sediment; (4) lateral accretion and minor expansion to the north and formation of beachrock pavement between 2,500 and 650 cal yr BP; and (5) planform adjustment (erosion of the north‐west island) and backstepping under stabilised sea levels over the past 650 years. While this model is comparative to studies on island formation following incremental sea‐level fall following the mid‐Holocene highstand, it demonstrates active landform readjustment under stabilised sea levels over the past 2,000 years, probably the influence of local‐scale metocean boundary conditions within climate windows across the mid to late Holocene period (i.e. independent of sea‐level fluctuations). Importantly, while sediment production rates are predicted to be lower in turbid‐water reef systems than clear water, Eva Island shows no change in carbonate producers (i.e. proportion of mollusc and coral) over the course of island building, indicating the carbonate factory has not experienced significant adjustments in reef ecology, but has remained stable despite low water quality.

Assessment of soil erosion using WSA and SPR techniques for Giri watershed, Himachal Pradesh, NW Himalaya, India

A watershed is the result of several geomorphic processes such as weathering, erosion, degradation and aggradation which are influenced by several factors viz. tectonics, lithology, climate, landslides and mass wasting processes etc. In a tropical climate, watersheds contribute a significant amount of eroded material which is reflecting the impact of lithology, precipitation, tectonics, relief and anthropogenic activities. In the Himalayan region besides significant heterogeneity in lithology, stratigraphy, structure and tectonics, it is observed that variability is exhibited in climatic conditions over a small region. These factors contribute to the development of geomorphic landforms and are best studied in watersheds or river basins. In the present study, Giri Watershed (GW) is assessed to contemplate susceptibility to erosion for 66 sub-watersheds using geomorphic parameters. The prioritization of subwatersheds has been done using Weighted Sum Analysis (WSA) and Sediment Production Rate (SPR) methods. The quantitative analysis of subwatersheds is categorized into different priority classes viz. very high, high, moderate, low and very low, among which 27 subwatersheds have very high to high susceptibility to erosion.

Modeling of Soil Loss by Water Erosion and Its Impacts on the Cantareira System, Brazil

The Cantareira System is one of the largest water supply systems in the world, supplying about half of the water consumed by 22 million inhabitants in the Metropolitan Region of São Paulo, in southeastern Brazil. In this scenario, in view of climate change, silting is a serious environmental threat and a major challenge to the sustainability of water reservoirs. Therefore, identifying the provenance of sediments is an essential tool to support soil conservation policies, slowing erosion processes and mitigating the deposition of sediments in water reservoirs. Thus, this study aimed to model soil losses—sediment production, by water erosion in the Cantareira System, based on the RUSLE model—Revised Universal Soil Loss Equation, GIS—Geographic Information System and SR—Remote Sensing. The work was conducted on data obtained from online platforms of Brazilian public institutions. The results indicate an average rate of soil loss of 13 Mg ha−1 yr−1, which corresponds to an annual loss of 3 million tons, of which 22% reaches water bodies. The data also show that: (1) in 66 % of the Cantareira System, soil losses are below the soil loss tolerance limits, and, in 34% of the region, water erosion is compromising the sustainability of water and soil resources; (2) the areas with the greatest soil losses are predominantly located in planted forests, agricultural crops and non-vegetated areas; and (3) sectors with high rates of soil loss require the adoption of conservationist practices aimed at reducing sediment production rates and thereby increasing supply and improving water quality.

Prioritization of Sub-watersheds for the Categorization of Surface Runoff and Sediment Production Rate Based on Geo-spatial Modeling and PCA Approach: A Case from Upper Beas River, Himachal Pradesh, India

Abstract Studying geo-morphometric parameters using Remote Sensing (RS) and Geographic Information System (GIS) tools is crucial to routing runoff and remaining hydrological processes. A geo-spatial model and principal component analysis (PCA) approach are used in this study to prioritize sub-watersheds of the upper Beas river up to Pandoh dam. Dendritic drainage patterns throughout its sub-watersheds characterized the 6th-order Beas river. The sub-watersheds show a lithological uniformity that indicates that the entire watershed has structurally impermeable materials at both surface and sub-surface levels. Moreover, the aerial and relief aspects of the sub-watershed indicate fine drainage textures, steep slopes, immediate peak flows, a hydrograph with multiple peaks, and a low concentration time. In other words, the sub-watershed may not be able to manage flash floods during the storm period. Surface runoff and sediment production rates (SPR) were estimated in the present study ranged from 3.576 - 5.240 sq. km-cm/sq.km and 0.101 - 0.234 ha-m/100sq.km/year, respectively. Finally, the study concluded that the sub-watersheds in the upper regions produced high runoff and sediments, usually carried into the mainstream. Further, the PCA technique was applied to find the redundant morphometric parameters and then the same results were utilized to determine the effective way to prioritize the watershed. The present study will serve as a basis for developing appropriate policies and practices for peak flooding and promoting the sustainability of the watershed.

Impact of Inherited Foreland Relief on Retro‐Foreland Basin Architecture

AbstractWe use a Landscape Evolution Model including flexural isostasy to investigate the influence of inherited foreland relief on the stratigraphic evolution of the retro‐foreland domain during mountain building. We show models with four different types of initial relief in the foreland domain: at sea level, elevated (+300 m), a 1 km‐deep and 100 km‐wide foreland basin associated with either a forebulge at sea level or elevated at +300 m. During the first 10 Myr of simulation, the landscape evolution of the foreland is significantly altered by its inherited bathymetry/topography. The impact is then smoothed out once the foreland slope has stabilized and develops a transverse drainage network. Models record a long‐term shallowing‐up mega‐sequence driven by the increase in sediment production rate in the uplifting range and the decrease in the rate of flexural accommodation space creation in the foreland basin. The initial relief of the foreland domain alters the timing of its transition from the under‐filled to the over‐filled phase. An initially deep foreland basin is twice as thick as an initially elevated foreland. It records deep marine deposits while a foreland initially at sea level records thin shallow marine and an elevated foreland records continental deposits. The forebulge is buried by continental deposits in an initially elevated foreland while it is buried by marine sediments in other models. Alluvial fans at the foot of the range are more elevated in initially elevated forelands. We discuss our results of modeled stratigraphic architecture in comparison with the Pyrenean, Alpine and Andean retro‐foreland basins.

The EPM model as a tool for analyzing the impact of dams on sediment production

The implementation of the EPM model on a time scale aims to reconstruct the production of sediment in a specific time range. The results will be compared with the evolution of the correlated physiographic unit and over the same time period.The sediment production rates analysis shows an increase in production between 1990 and 2018.The trend is in contrast with the evolution of the shoreline, in fact, the coastal physiographic unit is affected, in various sections, by a progressive and constant retreat. A possible cause could be related to dams construction along the Ofanto River.For each dam have been identified: (i) the starting year of commissioning, (ii) the area of the basin involved and (iii) an estimate of the potential impact on the production of sediment. The start-up of the San Pietro dam at the end of the 1950s and the Locone and Conza dams at the beginning of the 1990s are matched by a strong increase in the erosion process along the entire physiographic unit.The results of the study show that the use of the plug-in YES allows to map the areas of greatest impact on the production of sediment and to estimate the volume, providing important information in feasibility studies and dam management. In addition, the plug-in YES and its implementations also find potential in the implementation of VIA studies (environmental impact assessment) for the ability to assess the actual impact of the dam on the environment.

Seagrass meadows are important sources of reef island-building sediment

The future vulnerability of low-lying atoll nations is inextricably linked to the production of carbonate sediments by organisms living in their adjacent marine environments. Seagrass meadows are commonly found adjacent to reef islands, but their role as sources of reef island-building sediments has been overlooked. Here, we combine field, satellite and sedimentological data to quantify rates of sediment production by seagrass epibionts in a reef island sediment supply context. Total seagrass epibiont sediment production at our study site (Huvadhoo Atoll, Maldives) was 853,000 ± 90,000 kg CaCO3 yr−1 over an area of 1.1 km2. Of this total sediment production, 541,000 ± 23,000 kg CaCO3 yr−1 was estimated to be suitable to contribute to reef island building (sand-sized, post-agitation). Our findings highlight a valuable ecosystem service provided by tropical seagrass meadows as important potential sources of reef island-building sediment. This study, therefore, presents a compelling geomorphic argument for seagrass conservation.

Three Decades of Road and Trail Runoff and Erosion Work in the Northeastern Caribbean – a Research Program Perspective

HighlightsThe infiltration capacities of unsurfaced roadways are frequently exceeded by rain intensity, promoting overland flow.Erosion rates from unsurfaced roadways and cut slopes are 101 to 104 times greater than on undisturbed hillslopes.Roads in steep, subtropical wet terranes may increase landslide erosion by a factor of 5 relative to areas without roads.The hydro-geomorphic impact of roads is so prominent that they must be explicitly considered in watershed assessments. ABSTRACT. Erosion is a key environmental concern in the northeastern Caribbean because it can diminish soil productivity, damage infrastructure, and threaten human life. Additionally, sediment released by erosion can be delivered to streams where it can degrade water quality and aquatic habitat, reduce reservoir storage capacity, and threaten critical marine resources such as sea grass beds and coral reefs. Road erosion has been a concern in the region since the 1990s, and a considerable body of research has been conducted over the last ~30 years. This article reviews the key findings and identifies additional research needs. In some tropical dry coastal watersheds of the US Virgin Islands and Puerto Rico, unpaved roads and foot or off-road vehicle trails are the primary sediment sources. Watershed scale sediment production rates in these tropical dry settings are 0.3 to 3.7 Mg ha-1 yr-1, depending on unpaved road density, and these are 3 to 40 times greater than under undisturbed conditions. In wetter settings, like the forested and actively cultivated landscapes of highland Puerto Rico, sediment contributions include those from unpaved farm roads but also those from croplands, streambanks, and landslides. Watershed scale sediment production rates in actively cultivated tropical wet settings are 15 to 60 Mg ha-1 yr-1, with road-induced surface erosion and landslides accounting for 50% to 95% of total sediment production. Designing management alternatives will require additional research to improve our understanding of road-to-stream and road-to-coast connectivity, develop effectiveness metrics of applied management practices, and establish the specific causes of road-induced landslides. Keywords: Connectivity, Coral reefs, Landslides, Puerto Rico, Sedimentation, Surface erosion, Virgin Islands.

Soil erodibility mapping using watershed prioritization and morphometric parameters in conjunction with WSA, SPR and AHP-TOPSIS models in Mandakini basin, India

ABSTRACT The Himalayan region is the most sensitive due to its fragility, especially in soil erosion; therefore, it is a growing concern for environmentalists and natural resource planners. The study river basin Mandakini is situated in the central part of the Garhwal Himalayan region (Uttarakhand, India), which is highly prone to soil erosion due to various hydro-geomorphological factors. The factors include precipitous slope, geology, rugged terrain, land use and drainage pattern. Therefore, to identify the erosion-prone areas of the study basin, employed watershed prioritization technique using geographical information system and remote sensing integrated with weighted sum analysis (WSA), sediment production rate (SPR) and Technique of Order Preference Similarity to the Ideal Solution with Analytical Hierarchical Process (AHP-TOPSIS) models. It is calculated by taking different parameters indicating linear, landscape, and shape parameters. All the sub-watersheds (SW) of the basin were prioritized in different categories for all models with model performance for the Mandakini river basin in the central Himalaya. The results are showing almost similar results except for high erosion-prone regions. The results of the SPR model indicate that vary large areas (43.47%) of the basin suffering from severe erosion limited in the north-central (WS11, WS12, WS21), eastern (WS2), and southern (WS22 and WS23) parts of the basin among 23 sub-watersheds. The result of model evaluation indicates AHP-TOPSIS is the efficient model in assessing soil erodibility. The study can help to undertake the precise decisions to propose an effective framework for soil erosion control measures and encourage soil conservation priorities of the region. The findings have implications for defining sustainable land resource management and conservation, which are critical to attaining the United Nations’ 2030 Agenda for Sustainable Development's societal goals.

The influence of glacial topography on fluvial efficiency in the Teton Range, Wyoming (USA)

This study examines the role of topography as a dynamic boundary condition that limits the efficiency of fluvial erosion in the post-glacial Teton Range landscape. The volume of sediment currently stored in two major catchments was estimated using high-resolution LiDAR and geometric reconstructions of depth to bedrock. Seismic reflection data in Moran Bay reveals post-glacial sediment preserved behind a submerged moraine, which isolates the bay from the larger Jackson Lake depocenter. The volume of post-glacial sediment stored in the canyons and bay totals 173.82 ± 19.5336.0 (×10−3 km3), which translates to a catchment-wide sediment production rate of 0.17 ± 0.02 mm/yr. The rock-equivalent sediment volume in Moran Bay is 4.4 ± 0.9 (×10−3 km3), only ∼2.6% of the total post-glacial volume. While the estimated sediment production rate in the canyons is similar to the uplift rate, the denudation rate derived from Moran Bay sediment is 0.004 ± 0.001 mm/yr, implying highly inefficient post-glacial sediment transport. The fluvial system has been disequilibrated by glacial erosion such that interglacial valley profiles lack the steepness needed to transport sediment, delaying sediment evacuation until the next glacial advance, or until uplift sufficiently steepens the fluvial system so that it regains efficiency. Furthermore, colluvial production rates in the deglaciated valleys are close to long-term denudation and uplift rates, suggesting that once topography has been equilibrated to glacial erosion processes, subsequent glaciers do not need to produce much bedrock erosion, but mainly sweep out accumulated sediment to maintain equilibrium.

Suspended sediment transport in a tropical river basin exhibiting combinations of land uses/land covers and hydroclimatic conditions: Case study of upper Athi Basin, Kenya

Study regionThe Upper Athi River Basin (Lat: 1°25′17.61°S and Long: 37°15′29.55°E) in Kenya, East Africa. Study focusThe effects of land use/land cover type on suspended sediment concentrations and yield were investigated in the upper Athi river basin in Kenya. The suspended sediment concentrations and yield, river discharges, water levels and flow velocities were monitored in stations established at the outlets of sub-basins and also at the outlet of the main basin in period 2012–2015. New hydrological insightsThe magnitude of river discharge in the upper Athi river basin is not only a function of the magnitude of rainfall, but combination of land uses/land covers determined the magnitude of sediment yield in the sub-basins. The highest sediment yield occurred in a semi-arid sub-basin dominated by savannah grassland and livestock grazing. The lowest occurred in the high rainfall sub-basins dominated by forest with mixed farming and settlements. Significant sediment transport commenced at an effective river discharge of 405 m3s−1 which is a frequent discharge event resulting in significant sediment load transport in most rainy seasons and years. The magnitude of suspended sediment discharge is a function of the magnitude of rainfall such that the greatest sediment transport occurs during the long rainy seasons (54%) as compared to 41% during the short rainy season. The total annual suspended sediment load in the basin ranged 2.11–3.77 × 106 tons.yr−1 and sediment production rate ranged 205–366 tons.km−2.year−1.

Assessment of soil erosion risk in a semi-arid climate watershed using SWAT model: case of Tata basin, South-East of Morocco

Increased sedimentation is the main problem that affects dam efficiency by reducing storage capacity. Planning for dam construction and maintenance requires design strategies that heavily depend on integrated basin models, properly identifying principal sediment origins within the watershed and qualifying the sediment production rate. In this research work, the physically-based watershed SWAT model, defined as the Soil and Water Assessment Tool, was used to estimate the rate of sediment production for future dams in the Tata basin, located in southeast Morocco. The model was calibrated and tested for uncertainty by the employment of the algorithm Sequential Uncertainty Fitting-2. The outputs were used for assessing critical sediment source areas. Calibration and validation of the model were performed by monthly data. The values for Nash–Sutcliffe efficiency coefficient, Percent bias coefficient and determination coefficient (R2), respectively, during the calibration period 1990–1998 (0.96, −13% and 0.96) and the validation period 1999–2006 (0.77, + 11% and 0.93) indicate the accordance with the results obtained for the measured flow and the simulated flow values. The annual sediment yield of the Tata basin extends from 0 to 11 t/ha/y with a mean of 2.3 t/ha/y. The spatial distribution of these sediments varies from upstream to downstream. The downstream basin generated more sediment to the river per unit area, though it was less than the total amount of the basin for the upstream area. This variation is influenced by the increased downstream surface runoff and also by other characteristics of the basin such as slope and lithology. The low erosion places correspond to areas with lithological formations that are more resistant to erosion.

Identification of Prone Areas of Soil Erosion Using Modified Morphometric Prioritization and Sediment Production Rate (Case Study of Kamyaran Basin)

Identification of Prone Areas of Soil Erosion Using Modified Morphometric Prioritization and Sediment Production Rate (Case Study of Kamyaran Basin)

Comparative geomorphometric approach to understand the hydrological behaviour and identification of the Erosion prone areas of a coastal watershed using RS and GIS tools

Assessment of the geomorphometric parameters using Remote Sensing (RS) and Geographic Information System (GIS) tools forms an important part in routing the runoff and other hydrological processes. The current study uses a geospatial model based on geomorphometric parameters for the categorization of surface runoff and identification of the erosion-prone areas in the watershed of the Kuttiyadi River. The 4th order Kuttiyadi river is dominated by a dendritic to semi-dendritic drainage pattern in the subwatersheds. The linear aspect of the subwatersheds indicates towards the presence of permeable surface and subsurface materials with uniform lithology. The aerial and relief aspects of the subwatersheds shows fine drainage texture, gentle slopes, delayed peak flow, flatter hydrograph, and large concentration time which shows that subwatersheds are quite capable of managing flash floods during storm events. The estimated values of surface runoff (Q) and sediment production rate (SPR) are range from 2.13 to 32.88 km2-cm/km2 and 0.0004–0.017 Ha-m/100km2/year respectively and suggest that Subwatershed 1 (SW1) will generate more surface runoff and is prone to soil erosion followed by subwatershed 2 (SW2) in comparison to other subwatersheds. This paper aims to fill the knowledge gap regarding categorization of flow and erosion dynamics in a coastal river watershed. We believe that our work may work help in providing the crucial information for decision-makers and policymakers responsible for establishing suitable policies and sustainable land use practices for the watershed.

How do carbonate factories influence carbonate platform morphology? Exploring production−transport interactions with numerical forward modelling

AbstractUnderstanding how carbonate factories influence platform evolution is either based on qualitative conceptual models or quantitative numerical stratigraphic forward models. This study establishes new production depth profiles for four Cenozoic carbonate factories and uses two‐dimensional stratigraphic forward models to explore how interactions between sediment production and transport within carbonate systems influence carbonate platform development. Newly established production/depth profiles are used to model photozoan and heterozoan carbonate grain associations, and the associated carbonate producing factories, and results are compared with well‐studied outcrop successions. Sediment production from photozoan and heterozoan grain associations is also equalized, so that the total sediment production is the same but the depth/production profiles retain their distinctly different form. Thus, the effect of the different production profiles can be assessed. Ramps form when sediment diffusional transport rates are high relative to production rates and flat‐top steep‐margin platforms form when sediment diffusional transport rates are low relative to production rates, whether they are photozoan or heterozoan grain associations. The control exerted by sediment production and transport is expressed as a sediment transport–production ratio where transport ratio is a diffusional sediment transport in two‐dimensions and production ratio is the total sediment production rate which is the product of a production profile that varies in depth and laterally. The transport–production ratio is a key control on the evolution and geometry of carbonate platforms. This is the case with different production profiles (both euphotic and oligophotic) and in mixed grain‐size and mixed transport‐rate systems. Carbonate producing factories significantly influence the rate of sediment production, the depth distribution of sediment production (production profiles), as well as the type of grain sizes produced (influencing resistance to erosion). Thus, different types of carbonate grain associations, and the associated carbonate producing factories, can produce the critical differences between carbonate platform geometries.