Tons Of Suspended Sediment Research Articles

Soil erosion vulnerability and soil loss estimation for Siran River watershed, Pakistan: an integrated GIS and remote sensing approach.

Soil erosion is a problematic issue with detrimental effects on agriculture and water resources, particularly in countries like Pakistan that heavily rely on farming. The condition of major reservoirs, such as Tarbela, Mangla, and Warsak, is crucial for ensuring an adequate water supply for agriculture in Pakistan. The Kunhar and Siran rivers flow practically parallel, and the environment surrounding both rivers' basins is nearly identical. The Kunhar River is one of KP's dirtiest rivers that carries 0.1 million tons of suspended sediment to the Mangla reservoir. In contrast, the Siran River basin is largely unexplored. Therefore, this study focuses on the Siran River basin in the district of Manshera, Pakistan, aiming to assess annual soil loss and identify erosion-prone regions.Siran River average annual total soil loss million tons/year is 0.154. To achieve this, the researchers integrate Geographical Information System (GIS) and remote sensing (RS) data with the Revised Universal Soil Loss Equation (RUSLE) model. Five key variables, rainfall, land use land cover (LULC), slope, soil types, and crop management, were examined to estimate the soil loss. The findings indicate diverse soil loss causes, and the basin's northern parts experience significant soil erosion. The study estimated that annual soil loss from the Siran River basin is 0.154 million tons with an average rate of 0.871 tons per hectare per year. RUSLE model combined with GIS/RS is an efficient technique for calculating soil loss and identifying erosion-prone areas. Stakeholders such as policymakers, farmers, and conservationists can utilize this information to target efforts and reduce soil loss in specific areas. Overall, the study's results have the potential to advance initiatives aimed at safeguarding the Siran River watershed and its vital resources. Protecting soil resources and ensuring adequate water supplies are crucial for sustainable agriculture and economic development in Pakistan.

Retention of suspended sediment and phosphorus on a freshwater delta, South Lake Tahoe, California

The Upper Truckee River and Trout Creek, two major tributaries inflowing to Lake Tahoe, join to form what was historically the largest wetland in the Sierra Nevada mountain range that separates California and Nevada (USA). In the 1950s the delta floodplain of the Upper Truckee River was greatly reduced in area (38%) by urban development and the diversion of the river into a single excavated channel. Conversely, Trout Creek still flows through a wide marsh system with significant overbank flooding before entering Lake Tahoe. This study hypothesized that river channel reaches that are not incised within the delta floodplain retain more sediment and nutrients as a result of greater floodplain connectivity, compared to more incised and excavated reaches. Suspended sediment (SS) and total phosphorus (TP) load data from the delta formed by the Upper Truckee River and Trout Creek were collected using flow stage sensors, turbidometers and depth-integrated samples. During the spring snowmelt flow events monitored in 2003, SS load was reduced by 13–41% for the Upper Truckee River and by 68–90% for Trout Creek. Similar reductions in TP load were observed: 13–32% for the Upper Truckee River and 61–84% for Trout Creek. Monitoring of Trout Creek indicated a reduction in load per unit volume of 20–34% in a moderately incised reach versus a reduction of 51–77% in a non-incised marsh reach containing lagoons, braided channels and backwater areas created by a beaver dam. Smaller particle sizes, <10 μm, were retained in the lower marsh reach with similar efficiencies as larger particle sizes. If retention rates from the Trout Creek portion of the marsh are applied to the Upper Truckee River, sediment loading to Lake Tahoe for 2003 would have been reduced by 917 tons of SS.

Soil loss and sediment transport during the storms and landslides of May 1988 in Ruhengeri prefecture, Rwanda

In early May 1988, five prefectures in western Rwanda experienced catastrophic levels of precipitation, landslide, and flooding activity that resulted in a severe loss of life, property, and livelihood. Using data from runoff plot and hydrological monitoring stations of the Ruhengeri Resource Analysis and Management Project, the events and circumstances leading to these phenomena are reconstructed. These data show that mass wasting processes were preceded by more than 140 mm of precipitation during 4–7 May, which may have saturated local soils. A small earth tremor on 7 May, (Richter scale of 3) contributed to the onset of the catastrophic debris avalanche, torrent, and earthflow activity that commenced 24 h later. The more than 50 mm of precipitation that fell during 9 May, including a maximum 30 min intensity of 24 mm, resulted in continued surficial soil loss that averaged 34 t/ha on seven cropped, Wischmeier-type runoff plots with biological erosion control contours. The Nyamutera River, which drains the impacted area, delivered 567000 tons of suspended sediment to its mouth between 7 and 13 May. This corresponds to a basin-wide lowering of 12600 t/km2, or more than half of the basin's annual suspended sediment yield. Theoretical distributions of maximum 24 h precipitation events suggest that Nyakinama and other regions in Ruhengeri are particularly prone to similar high volume events, exacerbating an already serious soil loss problem throughout the prefecture. Because contemporary land use practices directly contributed to the severity of the 1988 event, further applied research that identifies technologies capable of reducing soil loss, augmenting soil fertility, and minimizing the impacts of high magnitude and high volume rainfall is greatly needed.

World-Wide Delivery of River Sediment to the Oceans

New data and new estimates from old data show that rivers with large sediment loads (annual discharges greater than about $15 \times 10^{6}$ tons) contribute about $7 \times 10^{9}$ tons of suspended sediment to the ocean yearly. Extrapolating available data for all drainage basins, the total suspended sediment delivered by all rivers to the oceans is about $13.5 \times 10^{9}$ tons annually; bedload and flood discharges may account for an additional $1-2 \times 10^{9}$ tons. About 70% of this total is derived from southern Asia and the larger islands in the Pacific and Indian Oceans, where sediment yields are much greater than for other drainage basins.

Suspended Sediment Discharge of the Susquehanna River to Northern Chesapeake Bay, 1966 to 1976

Between 1966 and 1976, the Susquehanna River at Conowingo, Maryland, discharged approximately 50 million metric tons of suspended sediment to Northern Chesapeake Bay. About 40 million metric tons were discharged in two floods associated with hurricanes: Agnes (24–30 June 1972) and Eloise (26–30 September 1975). In the six years with complete records and no major floods, the Susquehanna River discharged 0.9±0.3 million metric tons of suspended sediment per year at Conowingo Dam. Aout 50 to 60 percent of the annual sediment discharge is usually floods, suspended sediment transport at Harrisburg, Pennsylvania, exceeds sediment discharge at Conowingo, Maryland, probably due to sediment deposition in the lower river and behind three hydroelectric dams.

The Rufiji River, Tanzania Hydrology and Sediment Transport

Sediment transport by large tropical rivers has generally not received adequate study due to deficiencies in recorded data on discharge and sediment load. This paper is a case study of sediment transport in the Rufiji river, which drains a varied catchment of 156,600 km2, and is the largest river in Tanzania.Data on suspended sediment load spans the period 1955/56 to 1961/62, while discharge data covers the period 1954/55 through 1969/70. During this period, daily discharges ranged between 6637 m3/sec and 69 m3/sec. Floods with a discharge of 5000 m3/sec have a return period of approximately 5 years. Suspended sediment load data fortunately covers the extremes of the river record as well as more normal conditions. Suspended sediment load data indicates a maximum daily transport of approximately 1,000.000 tons during the investigated period. Sediment-rating-curve and duration-curve analyses indicate that some 250–300 mill, tons of suspended sediment have passed through Stiegler's gorge in the 16 years covered by discharge records. To this figure should be added the bed load transport and probably also a certain increase due to inaccuracy in the sampling and analysis procedures.Heaviest loads of sediment are related to sudden flash floods in the rising limb of the annual hydro- graph. The suspended sediment peaks are out of phase with the flood peaks, indicating an early annual flushing of sediment from the system with the onset of the flood season. The sources of this sediment and the characteristics of the tributary basins in terms of relief, geology, seasonal rainfall regimes, and vegetation are discussed.Geomorphological and economic implications are discussed in general but will be covered more fully in a later report.

Annual Suspended Sediment Supplied to the California Continental Borderland by the Southern California Watershed

ABSTRACT Prominent southern California streams were sampled at their mouths during a rainy season to determine the concentrations, grain sizes, mineralogy and quantities of suspended sediment supplied to the ocean by the southern California watershed. Approximately 3.5 million tons of suspended sediment are brought to the ocean annually by southern California streams. Some 0.8 million tons are arkosic sands, and the remaining 2.7 million tons of river-supplied sediment are silts, clays, colloids and dissolved material. The total annual supply of sand to the California coast has been previously estimated at 5 million tons. Approximately 4.2 million tons of sand can be attributed to stream traction load. It is concluded that southern California supplies 7.7 million tons Of terrigenous material to the Continental Borderland every year. This estimate agrees well with rates of supply which have been calculated from seismic profiling surveys.

Brahmaputra river: Channel processes and sedimentation

The Ganges and Brahmaputra rivers combined have formed one of the largest deltas in the world, comprising some 23,000 sq. miles. These rivers originate within the Himalayan Mountains and drain an enormous land area before entering East Pakistan. Individually, each of the rivers discharges in excess of 2.5 million cusecs of water during flood, and combined they carry nearly 6 million cusecs of water to the Bay of Bengal, nearly three times the amount borne by the Mississippi River. Having such a large drainage area, the rivers are also heavily charged with sediment, transporting approximately 13 million tons of suspended sediment per day during flood. The large discharge and heavy sediment load cause the rivers to be extremely unstable, and the channels are constantly migrating laterally. Within Recent times both rivers have occupied and abandoned numerous river courses. The Brahmaputra followed a route some 60 miles to the east of its present course only 200 years ago. The long-term patterns of river migration indicate that the Ganges has been migrating eastward, whereas the preferred migration of the Brahmaputra is westward. These movements are obviously controlled by major faults or fractures in the earth's crust. The Brahmaputra River displays a braided pattern in plan view, and short-term channel migration is quite drastic, with rates of movement as high as 2,600 ft. a year being common. The rate of rise and fall of the river, the number and position of major channels active during flood, the formation and movement of large bedforms, cohesion and variability in composition of bank material, and intensity of bank slumping are some of the factors responsible for controlling the bankline configuration and movement. The most significant bankline modifications take place during falling-river stage, when excess sediment is deposited as bars within the channel, causing a change in local flow direction and migration of the thalweg. Studies of bedform patterns and migration indicate that during a single flood cycle the bed configuration undergoes a definite sequence of changes. During low-river stage small bedforms (WH = 1–5 ft.) are present and migrate downstream at an average rate of 400ft./24 h. As discharge increases, the bedforms grow in size (WH = 5–20 ft.), and surface turbulence assumes a regular pattern on the water surface. During maximum-flood period some of the bedforms attain gigantic size, with heights up to 50 ft., and migrate downstream at rates as high as 2,000 ft./24 h. At other positions in the channel a plane bed exists, and surface turbulence patterns become oriented parallel to the channel axis. Although quite different in scale, this sequence is similar to that reported in flume studies. During low-river stage trenches on the various exposed bars revealed the type of bedding formed by migration of the various bedforms. Crossbedding measurements at these stations were recorded and compared to sand body trends. The combined Bengal Basin rivers deliver some 1 billion tons of suspended sediment a year to the Bay of Bengal, yet map and photo comparisons indicate that the shoreline has remained quite stable. Most of the sediment brought to the bay bypasses the bar and continues on into deeper water through a canyon called the Swatch of No Ground. Thus in deep water a subaqueous delta is being formed that dwarfs the subaerial delta, one of the largest in the world.