Specific Suspended Sediment Yield Research Articles

The Signature of Climate in Fluvial Suspended Sediment Records

AbstractArid regions are often characterized by exceptionally high rates of fluvial sediment transport, but the processes responsible for this apparent connection between climate and sediment transport remain unclear. We examined decades of continuous flow records and suspended sediment concentrations from 71 rivers across the United States by comparing the suspended sediment rating curve behavior, quantified using power law coefficients and exponents, to an aridity index. Results indicate that higher aridity correlates with both greater overall suspended sediment concentration and lower sensitivity of concentration to changes in discharge, demonstrating that rivers in arid locations on average have greater suspended sediment transport efficiency across most discharges, and achieve high transport rates at a relatively lower discharge than rivers in temperate climates. Furthermore, based on additional analyses of the Normalized Difference Vegetation Index, specific suspended sediment yield, and a hydrograph flashiness index, we attribute the relationships between sediment transport and climate primarily to differences in vegetation density, precipitation, and runoff, variables that all influence both sediment supply and riverbed grain sorting. Finally, we note that the observed contrasts in sediment transport behavior likely represent climate‐driven differences in the magnitude and frequency of sediment supply rather than annual suspended sediment load, which does not depend significantly on climate. This study highlights a critical connection between multiple interrelated climatic factors and sediment transport, an important finding for future hazard mitigation in a changing climate with rapidly shifting vegetation patterns and hydrology.

Exploring the association between landslides and fluvial suspended sediment in a semi-arid basin in central Chile

The systematic monitoring of landslides is an essential input for their characterization and subsequent reduction of their risk. Along the western subtropical Andes, field monitoring is scarce, so alternative methods that can improve the monitoring are valuable. In this work, the capacity of fluvial suspended sediment to detect the occurrence of landslides in a basin was explored, emphasizing how the relationship varies depending on the hydro-sedimentological variable, the triggering causal factor and the landslide type. The values of suspended sediment concentration (SSC), water discharge (Q) and specific suspended sediment yield (SSY) associated with mass movements were collected from a fluviometric station, as well as maxima of these variables that were not associated with landslides. With these data, different General Linear Models were constructed considering possible non-linear effects of the covariates. Flow-type landslides triggered by rain (most of the events) are correctly predicted, especially using the linear effects of SSC and Q. For this mass movement type the prediction is suitable even for events triggered by isolated, short-lived rains, which are difficult to detect in mountainous areas with meteorological devices.

The intensity of siltation of a small reservoir in Poland and its relationship to environmental changes

Siltation of reservoirs is an indicator of the intensity of erosion processes and sediment yields of river catchments. An estimation of sediment yield is significant for hydroengineering practices, environmental prediction and modelling. It also reflects environmental changes in the form of climate and land use.The present study aimed to compare the amount of sediment deposited in a small reservoir in Poland, with the estimate of sediment yield from its catchment, using the Universal Soil Loss Equation coupled with a sediment delivery ratio (USLE-SDR) and an estimate of annual bed load transport, provided by a regional bed load formula. The estimate of the annual amount of bed load was based on the flow frequency graph and bed load rating curve of Skibinski. The dam of the reservoir was constructed in 1976. The first reservoir survey was carried out between 1979 and 1980, when the reservoir volume was estimated to be 252,000 m3. Subsequent surveys were carried out in 1991, 2003, 2009 and in the Spring of 2020. These surveys enabled the amount of sediment, deposited in the reservoir, to be measured across four different periods: 1980–1991, 1992–2003, 2004–2009 and 2010–2019. For the same periods, the USLE with a constant SDR (calculated using the approach provided by Vanoni) were used to estimate the quantity (mass) of suspended sediment yield from the contributing area of the catchment. The volume of suspended sediment, deposited in the reservoir, was obtained, taking into account the reservoir trap efficiency and assuming a density of suspended sediment deposits.Hydrological investigations of the Plachty gauging station on the Zagozdzonka River, the left tributary of the Vistula River, have been carried out by the Department of River Engineering at Warsaw University of Life Sciences since 1962. The catchment area at the Plachty gauging station, located just upstream of the reservoir, is 82.4 km2, whereas the catchment area above the dam of the Staw Górny reservoir, is 91.4 km2.The estimated annual sediment yields for the catchment, based on reservoir surveys across four periods between 1980 and 2020, suggest a general decrease over time. This study was also undertaken to examine long-term variability in sediment yield, both in suspended sediment and bed load, related to rainfall-runoff erosivity, river discharge and land use changes, which could influence changes in catchment sediment yield. An analysis of local temperature and catchment runoff revealed a long-term increase in the mean annual temperature and a corresponding decrease in annual discharge.The annual values of total sediment input to the reservoir (suspended and bed load), estimated using the USLE-SDR and a bed load formula with sediment trap efficiency, are very close to the measured amounts of deposits in the reservoir. Annual deposits in the reservoir are decreasing with time. This is presumably caused by the decrease in arable land in the catchment. From the mean annual deposits in the reservoir, around 35% is bed load and 65% is suspended load. The average annual specific suspended sediment yield in the catchment, is ca. 9 Mg/km2.

Analysing hydrological and sediment transport regime in two Mediterranean intermittent rivers

Flow and the sediment regime affect water quality and nutrient delivery in all river systems and are fundamental in sustaining the river ecosystem. This study aims to identify the most relevant factors affecting the flow regime and the suspended sediment transport in two Mediterranean intermittent rivers: the Búger (Spain) and the Carapelle (Italy). A set of hydrological indicators were used to characterize and classify the flow regime. High-resolution data, streamflow and suspended sediment concentration were used to quantify runoff and sediment yields at different temporal scales (annual, monthly, event). Rainfall, streamflow and sediment variables were used at the event scale to assess the rainfall-runoff-suspended sediment relationship through the Pearson correlation matrix. Hysteresis analysis provided information on sediment source dynamics. In the Búger River, the high degree of flow intermittence was mainly due to the presence of carbonate lithology and forest land use at headwaters promoting low values of runoff coefficient (2–10%) and specific suspended sediment yield (SSY; 0.5–46 t km−2 y−1). In the Carapelle River, the high values of annual runoff coefficient (14–35%), together with low flow intermittence and SSY (89–745 t km−2 y−1) were related to clay and flyschoid lithology. Most of the annual sediment yield (SY, t) was transported during floods. In Búger, SSY and maximum suspended sediment concentration (SSCmax, g l−1) were checked against runoff, peak discharge and antecedent rainfall. In Carapelle, SSY and SSCmax were checked against the amount and intensity of rainfall. The catchment size and the spatial distribution of rainfall, land uses and lithology played important roles in the flow regime, suspended sediment transport and hysteretic behaviour. Characterization of the flow regime linked to its main physical drivers improved understanding of the hydrological response and sediment transport variability of intermittent rivers. This study provided valuable insights into water resource management, improving the prediction of spatial patterns and of the intensity of sediment transport in river basins.

Suspended sediment yield characteristics variability in rivers of Kamchatka krai

The regularities of spatiotemporal variability of suspended sediment yield characteristics were studied. Based on the analysis of difference-integral yield curves, it was found that most of the rivers in Kamchatka krai are characterized by the presence of two relatively long trends in the suspended sediment yield variability: an increase until the end of the 1970s–early 1980s, and its subsequent decrease. This regularity disturbs in rivers under the influence of volcanic eruptions, where the most significant increasing of sediment yield is observed after major eruptions. Existent maps of mean annual suspended sediment concentration and mean annual specific suspended sediment yield were significantly specified (18 instead 4 and 13 instead two zones were marked respectively). The map of grain-size distribution of suspended sediment was compiled (three zones was marked in region under study). Maximum values of mean annual specific suspended sediment yield (more than 500 t km-2 yr-1), suspended sediment concentration (more than 1000 g m-3) and grain-size of sediments are observed in water runoff of volcanic areas. Minimum values of suspended sediment concentration, specific suspended sediment yield, as well as grain-size of sediments characterized the mainland part of the krai.

Sediment Yield of Kamchatka Krai Rivers into the Pacific Ocean and the Seas of Bering and Okhotsk

Sediment yield of Kamchatka Krai rivers into the Pacific Ocean and the seas of Bering and Okhotsk, is evaluated, including that from the drainage basins that are not covered by regular observations. Regression dependences of specific suspended sediment yield (SSSY) on factors determining it were constructed for erosion regions identified in Kamchatka Krai. The total average many-year yield of suspended sediments of Kamchatka Krai rivers into the Pacific is 11.4 × 106 t/year, 73.9% of which is transported by rivers of the eastern coast and 26.1%, by those of the western coast. Among other factors, such distribution is attributed to the location of the majority of volcanoes on Kamchatka eastern coast. About one third of all sediments transported from Kamchatka Krai territory is discharged by the two largest rivers in the region, i.e., the Penzhina and Kamchatka.

Modeling the impact of climate change on water resources and soil erosion in a tropical catchment in Burkina Faso, West Africa

Soil erosion is recognized as one main reason for soil degradation in West Africa. However, predictions on the impact of climate change on soil erosion are rare for most West African countries including Burkina Faso.This study assesses the impact of climate change on water resources and soil erosion in a small catchment (126km2) in southwestern Burkina Faso. Climate data from an ensemble of six regional (RCM) and global (GCM) climate models were used to run the physically based spatially distributed hydrological and soil erosion model SHETRAN. The Representative Concentration Pathways (RCPs) 4.5 and 8.5 were selected as future climate scenarios.Bias corrected precipitation and temperature required for the calculation of potential evapotranspiration were used as input for the SHETRAN model to simulate total discharge and specific suspended sediment yield (SSY). Discharge and SSY from simulations run with climate data were able to reproduce discharge and SSY from a simulation that used observed precipitation and temperature from the historical period (1971–2000).The impact of climate change on hydrology and soil erosion was assessed by comparing the historical period with the future climate scenarios (2021–2050). Most of the used climate models predict an increase of temperature between 0.9°C and 2.0°C. The bias correction did not alter the climate change signal of temperature. Large uncertainties among the RCMs-GCMs exist regarding the climate change signal of future precipitation. Some climate models predict an increased (5.9%–36.5%) others a decreased (6.4%–10.9%) or mixed signal. The applied bias correction did not reverse the climate change signal in most cases but it influenced magnitude and timing of precipitation. The ensemble mean suggests an increased discharge between 19.5% (RCP 8.5) and 36.5% (RCP4.5) and an increased SSY of the same order. In general, the climate change signal and the corresponding discharge and SSY predictions are afflicted with large uncertainties. These uncertainties impede direct conclusions regarding future development of discharge and erosion. As a consequence of the mixed signals, potential increase and decrease of future discharge and soil erosion have to be incorporated in climate change adaption strategies.

The transformation of the runoff of the suspended load in Kamchatkan rivers due to volcanism

This paper considers the influence of volcanic eruptions on the variation in the characteristics of the runoff of the suspended river load (suspended sediment concentration, discharge, rate of runoff, and grain-size distribution) on a variety of space–time scales (daily, seasonal, and long-term). The main factors that affect the yield of suspended load in rivers that flow in volcanic areas include the water runoff, drainage area, and the abundance of unconsolidated volcanic deposits. The areas of recent volcanism in Kamchatka are characterized by the maximum values of potential scour of particles, the mean long-term suspended sediment concentration, and specific suspended sediment yield. The largest increment in the transport of suspended river load in areas of volcanic activity is observed after major eruptions. The daily variations in the transport of suspended load are controlled by the water regime of rivers on the slopes of active volcanoes, namely, periodic cessations of surface runoff because of filtering into volcanic deposits.

Suspended sediment transport into a water supply reservoir in southern Ghana

Weija reservoir on the Densu river serves as a source of water supply to parts of Greater Accra and Central regions of Ghana. The Densu river basin is characterised by accelerated land degradation. A number of Integrated Water Resources Management (IWRM) interventions have been implemented in the basin. Reports suggest there has been an improvement of physicochemical parameters of the water resources. However, there is no recent study on fluvial sediment transport in the basin. This paper assessed sediment transport into the Weija reservoir via the Densu River. Weekly suspended sediment concentration and river discharge were monitored over a 1 year period to quantify sediment yield into the reservoir. The results indicated that total annual suspended sediment yield, and annual specific suspended sediment yield were 5375 t yr -1 and 2.0 t km -2 yr -1 , respectively. These were relatively low compared to results obtained by past studies on the Densu basin at upstream Mangoase (6146 t yr -1 and 2.49 t km -2 yr -1 ) and other river basins in Ghana. Parameters established from a yield rating curve indicated that parts of the basin were degraded and sediment transport in the basin was largely due to the availability of sediment in the catchment and not just due to high river discharges. The relatively low sediment transport at Weija may be indicative of the success of the IWRM interventions. It is recommended that these be sustained and/or intensified.

Exploring suspended sediment delivery dynamics of two Mediterranean nested catchments

AbstractThis paper investigates suspended sediment transport and dynamics of two nested agricultural lowland Mediterranean catchments with a difference of two orders of magnitude in the surface area (i.e., 1 and 264 km2). The effects of the drainage catchment area over the specific suspended sediment yield are assessed by using the nested approach over various timeframes. A detailed analysis of the rainfall–runoff–sediment transport relationships during the 2‐year study period shows that the hydrological and sedimentological responses were extremely variable for both catchments. Very low or no correlations were observed between the rainfall intensity and the selected hydrological variables and sediment loads. However, remarkable or high correlations were obtained between the rainfall intensity and the maximum and average suspended sediment concentrations, indicating that rainfall per unit time has little control on the hydrological response, but that, simultaneously, its high‐erosive power triggers sediment production, increasing the sedimentary response of the catchments. This study also illustrates how sediment is mainly transported during floods, producing predominantly clockwise hysteretic loops. Moreover, the small headwater catchment exerts a reduced (or even negligible) effect over the hydro‐sedimentary response of the larger downstream catchment, caused by the reduced sediment availability in a landscape with an inherent disconnection of the sediment pathways.

TWO EROSION SYSTEMS IN THE RIVER BASINS OF THE EARTH'S PLAINS AND THEIR MUTUAL TRANSFORMATION (PART II)

The investigations of erosion in various landscape zones of the Earth's plains prove the existence of two basic systems of erosion: the channel and the basin ones. The principle distinctions of these systems show itself in structure of erosion processes and accumulation of their products, in hydrological regime of rivers, in character of dependence of specific suspended sediment yield on river basin area, in structure and thickness of alluvium, in relation between alluvium and slope sediments, in dynamics of river channels, in some features of river valleys morphology, in degree of preservation of relic landforms in the river basin, in general tendency of relief development (valley partition or planation), in intensity of sediment accumulation within the river channels and the flood-plains, ponds, and reservoir, etc. The present river channel system of erosion is divided into two subsystems: one of humid and semi-humid moderate latitudes and one of humid and semi-humid tropical and equatorial latitudes. The present basin system of erosion is also divided into two subsystems: anthropogenic one and natural (semi-desert, savanna, and sub-arctic zones) one.

TWO EROSION SYSTEMS IN THE RIVER BASINS OF THE EARTH'S PLAINS AND THEIR MUTUAL TRANSFORMATION (PART I)

The investigations of erosion in various landscape zones of the Earth's plains prove the existence of two basic systems of erosion: the channel and the basin ones. The principle distinctions of these systems show itself in structure of erosion processes and accumulation of their products, in hydrological regime of rivers, in character of dependence of specific suspended sediment yield on river basin area, in structure and thickness of alluvium, in relation between alluvium and slope sediments, in dynamics of river channels, in some features of river valleys morphology, in degree of preservation of relic landforms in the river basin, in general tendency of relief development (valley partition or planation), in intensity of sediment accumulation within the river channels and the flood-plains, ponds, and reservoir, etc. The present river channel system of erosion is divided into two subsystems: one of humid and semi-humid moderate latitudes and one of humid and semi-humid tropical and equatorial latitudes. The present basin system of erosion is also divided into two subsystems: anthropogenic one and natural (semi-desert, savanna, and sub-arctic zones) one.

Spatial variability of suspended sediment yield in a gravel-bed river across four orders of magnitude of catchment area

The spatial variation in suspended sediment yield in the River Eden, Cumbria, UK, is quantified and examined from a process-based perspective to challenge existing models for scale dependency in sediment yield. Field measurements were used to quantify suspended sediment yields for 14 sub-catchments within a total catchment area of nearly 1400km2, including nine catchments defining a nested basin system starting from 1km2. A novel catchment characterisation system was developed, in which broad-scale landscape characteristics were quantified using existing datasets, types of sediment supply feature were identified in a field survey and their distribution across the catchment was quantified using a survey of air photographs. Specific suspended sediment yield was found not to be related to catchment area. The main fine sediment input was from the riparian zone, where many sediment sources were discrete areas of erosion such as sites with livestock poaching and streamside scars. Connectivity of the rest of the catchment was low. The dominant types of source in an area were related to its topographic, geologic and land use characteristics. Specific suspended sediment yields were higher in lowland sub-catchments where the higher land use intensity and greater extent of superficial sediment deposits resulted in higher erosion susceptibility. Two ‘process domains’ were identified: lowland and upland. It is suggested that these provide a simple concept for explaining spatial variability in sediment yields as a function of easily measurable catchment properties.

Spatial and temporal variability of suspended sediment yield in the Kamchatka Krai, Russian Federation

Abstract. Research into the spatial and temporal variability of suspended sediment flux (SSF, t year−1) has been conducted for rivers in the Kamchatka Krai (in the far east of the Russian Federation). The study of long-term fluctuations in SSF was based on difference-integral curve analysis. Most of the rivers in the region are characterized by two relatively long-term trends in SSF; increases from the late 1970s to the early 1980s, followed by a subsequent decline. Kamchatka was divided into regions based on similar conditions of specific suspended sediment yield (SSSY, t km−2 year−1) followed by a determination of the various factors controlling it. New maps of suspended sediment concentration (SSC, mg L−1) and SSSY for Kamchatka also were constructed and, based on this study, there currently appear to be 18 SSC and 13 SSSY regions, as opposed to 4 and 2 regions, respectively, as had been determined in the 1970s. The influence of volcanoes on SSF can be substantial, and can increase up to 5-fold after eruptions; SSC can reach 6∙105 mg L−1 in rivers draining the flanks of volcanoes.

Sediment yield of a forest river basin in Ghana

The Pra River Basin, located in south central Ghana is a forest basin that has been engulfed by certain anthropogenic activities particularly illegal small scale mining (popularly called galamsey) and serious concerns have been raised by stakeholders within the basin of the level of pollution due to the release of sediments into the water bodies. This study was undertaken to assess sediment yield levels within the Pra Basin through field data collection to ascertain stakeholder's perceptions and suggest remedial measures to the land degradation problem in the basin.Suspended sediment concentration measurements were undertaken for 10months in selected stream discharge measuring stations within the basin by coupling dip and integrated sampling approaches. Samples were analyzed using the evaporation method. Daily mean suspended sediment concentration was calculated from which monthly and annual suspended sediment yields were derived. Suspended sediment concentration (mg/l) and sediment yield (tyr−1) of the Pra Basin were found to be very high resulting in a high annual specific suspended sediment yield (tkm−2yr−1). Illegal small scale gold mining along the rivers and alluvial gold mining within the basin were found to be the probable cause for the high sediment levels of the rivers. To promote coordinated development and sustainable management of the resources of the basin, there is the need to resource agencies in charge of regulating natural resource utilization to control land use activities particularly galamsey. This will reduce fluvial sediment concentration and sustain good water quality of the rivers and promote socio-economic development in the basin.

Pertinent spatio-temporal scale of observation to understand suspended sediment yield control factors in the Andean region: the case of the Santa River (Peru)

Abstract. Hydro-sedimentology development is a great challenge in Peru due to limited data as well as sparse and confidential information. This study aimed to quantify and to understand the suspended sediment yield from the west-central Andes Mountains and to identify the main erosion-control factors and their relevance. The Tablachaca River (3132 km2) and the Santa River (6815 km2), located in two adjacent Andes catchments, showed similar statistical daily rainfall and discharge variability but large differences in specific suspended-sediment yield (SSY). In order to investigate the main erosion factors, daily water discharge and suspended sediment concentration (SSC) datasets of the Santa and Tablachaca rivers were analysed. Mining activity in specific lithologies was identified as the major factor that controls the high SSY of the Tablachaca (2204 t km2 yr−1), which is four times greater than the Santa's SSY. These results show that the analysis of control factors of regional SSY at the Andes scale should be done carefully. Indeed, spatial data at kilometric scale and also daily water discharge and SSC time series are needed to define the main erosion factors along the entire Andean range.

Muted responses of streamflow and suspended sediment flux in a wildfire-affected watershed

In August 2003 a severe wildfire burnt 62% of Fishtrap Creek, a 158km2 watershed in central British Columbia, Canada. Streamflows were obtained for the period 1980–2010 and suspended sediment fluxes were determined for the period 2004–2010 for Fishtrap Creek and these were compared to data for nearby Jamieson Creek, which was not affected by the wildfire. Peak streamflows in Fishtrap Creek after the wildfire were not significantly higher than before the wildfire, although total annual runoff had increased. Perhaps the most important change in streamflows following the wildfire was that peak flows associated with the annual freshet occurred earlier in the year (by ca. 2weeks). Following the wildfire, monthly total suspended sediment fluxes peaked in April in Fishtrap Creek and May in Jamieson Creek, which reflects the change in timing of peak streamflows in Fishtrap. Specific suspended sediment yields were low in the first year following the wildfire (2004), and peak values for the 2004–2010 monitoring period occurred in 2006. Average specific suspended sediment yields over the monitoring period were similar for both watersheds at 2.8 and 2.9tkm−2year−1 for Fishtrap and Jamieson watersheds, respectively. The muted responses of streamflows and suspended sediment fluxes following this severe wildfire are due to the lack of winter precipitation and the low intensities of summer rainfall events in the first year following the wildfire. Greater winter precipitation and associated snowmelt in subsequent years coincided with vegetation recovery. The major changes in the wildfire-affected watershed were increased bank erosion and channel migration due to a loss of root strength and cohesion, which occurred 3–5years after the fire. This work demonstrates that the hydrological and geomorphological responses of watersheds to wildfires are a function of the severity of the wildfire and the timing and nature of driving forces (i.e. rainfall intensity, winter precipitation and snowmelt) during the progression of vegetation recovery.

Sediment Discharges from Ghanaian Rivers into the Sea

Information on sediment yield of a river basin is an important requirement for water resources development and management. In Ghana, data on suspended sediment yield are limited owing to lack of logistic support for systematic sediment sampling activities. The paper presents the results of a study, using measurements of suspended sediment transport for 21 monitoring stations in southern Ghana to develop simple predictive models for suspended sediment yields of catchments for which no sediment measurements had been undertaken. Regression analysis was used to establish a relationship between specific suspended sediment yield and both the mean annual runoff, and the drainage basin area. One of the prediction models was used to estimate the sediment loads of the southern Ghana rivers and total suspended sediment discharges into the sea, in addition to specific suspended sediment yields from the drainage basins. The specific suspended sediment yield for the south-western and coastal basin systems ranged between 11 and 50 t km –2 year –1 . The annual sediment discharges into the sea by the rivers ranged between 15,000 and 1.2 × 10 6 t, and total yearly sediment discharge into the sea by Ghanaian rivers is estimated to be 2.4 × 10 6 t.

Specific suspended sediment yields of the Andean rivers of Chile and their relationship to climate, slope and vegetation

Using daily suspended sediment and water discharge data, we calculated the current mean annual runoff and Specific Suspended Sediment Yield (SSY) for 66 mountainous and piedmont catchments in Chile. These catchments are located from the extreme north of Chile to Southern Patagonia and cover an exceptionally wide range of climates, slopes, and vegetation. The SSY ranges mainly between 0 and 700 t km-2 year-1 with some exceptions as high as 1780 t km-2 year-1. The SSY increases between the extreme north and 33°S and then decreases toward the south. Sediment and water discharge north of 33°S occur mainly during summer. Farther south the contribution of winter precipitation increases and predominates. When the SSY database is correlated with topographic, climatic and vegetation indices, it is found to correlate significantly with runoff and mean slope only. In order to concentrate on erosion processes in the mountain range, 32 mountainous catchments were selected along a strong north–south SSY gradient between 27°S and 40°S. From north to south, SSY increases strongly with runoff and then decreases, even while runoff keeps increasing. In catchments where SSY is low, although runoff is high, the mean slope is less than 40% and the vegetation cover is greater than 8%. For the other catchments, runoff variations explain 67% of the variance in sediment yields. Thus, SSY seems to be controlled by vegetation cover and slope thresholds. In addition, SSY also correlates with glacier cover. However, a correlation between SSY and seismicity, although possible, is ambiguous. Citation Pepin, E., Carretier, S., Guyot, J. L. & Escobar, F. (2010) Specific suspended sediment yields of the Andean rivers of Chile and their relationship to climate, slope and vegetation. Hydrol. Sci. J. 55(7), 1190–1205.

The assessment of suspended sediment inputs to Volta Lake

AbstractInformation on a river basin's sediment yield is an important requirement for water resources development and management. In the Volta River basin of Ghana, data on suspended sediment yield are limited due to the lack of logistic support for systematic sediment sampling activities. This paper presents the results of a study using the available measurements of suspended sediment transport for eight monitoring stations in order to develop a simple predictive tool for estimating the suspended sediment yields for catchments for which no sediment measurements had been undertaken. Regression analysis was used to establish a relationship between specific suspended sediment yield and both the mean annual run‐off and the drainage basin area. The prediction model was used to estimate the sediment loads of the Volta River and its main tributaries (Black Volta, White Volta and Oti Rivers) in order to estimate the total suspended sediment input to the reservoir and the equivalent specific suspended sediment yield from the catchment surface. Although these sediment yield values are relatively low by world standards, the results obtained provide a basis for assessing future sedimentation problems in Lake Volta and for underpinning the development of sediment control and management strategies for the reservoir.