Showing papers on "Siltation published in 2002"

Comparison between rainfall simulator erosion and observed reservoir sedimentation in an erosion-sensitive semiarid catchment

Abstract: Estimating catchment scale soil loss based on rainfall simulators is often hampered by the difficulty to scale up simulator results. Our objective was to develop and test a method for estimating catchment scale soil loss based on observed rainfall using a variable intensity rainfall simulator in an erosion-sensitive catchment in semiarid Tunisia. A 7-year period, 1992–1999, with observed sedimentation amounts in a downstream reservoir was chosen to test a methodology. The methodology was based on (1) energy adjustment for the used simulator due to the difference in kinetic energy of simulated and natural rainfall at equal intensities and (2) upscaling of simulated erosion in which rill erosion was estimated by adjusting the difference between slope lengths for the plots versus the catchment after onset of runoff. The comparison between calculated soil loss from rainfall simulator experiments and observed sedimentation in the downstream reservoir displayed good overall results. Calculated soil loss was found to be about 96%, 36%, and 80% for different observed subperiods, respectively. The observed low value for the second period was probably due an exceptionally intense rainfall event during this period, which appears to have led to gully erosion, soil slide, and riverbank collapse. Therefore, during this event, siltation in the reservoir may essentially be due to unaccounted erosion processes such as gully erosion. Overall, however, it appears that plot-scale variable intensity rainfall simulators can rather successfully estimate catchment scale soil losses.

Sediment properties along gradients of siltation in south-east Asia

Abstract: Marine sediment properties were quantified along SE Asian siltation gradients and across different habitat types to assess the extent of terrestrial sediment influence and derive indicators of of terrestrial sediment input. Three sites in the Andaman Sea (Ranong, Phuket and Trang; Thailand), one site in the Gulf of Thailand (Pak Phanang; Thailand) and three sites in the South China Sea (Bolinao at the Luzon Island, Puerto Galera at the Mindoro Island and El Nido at the Palawan Island, all in the Philippines) were studied. The following main habitat types were covered: mangroves, seagrass beds, coral reefs, mud flats, river mouths and deep channels. Particularly in Bolinao and El Nido, distinct fronts in siltation were identified at about 7 km from the source. Mud ( 250 m), total and inorganic carbon as well as calcium. Interstitial ammonia and phosphate varied with the fine sand fraction along the second axis. Two-way analysis of variance showed that water depth, distance from silt source, site and habitat type all contributed to the variance, but site explained most. Linear regressions showed positive correlations between silt and water content, organic matter, total nitrogen, total phosphorus and iron, but negative correlations with calcium suggesting iron and calcium as markers for terrigeneous and marine origin, respectively. The composition of the sediment particulate matter groups the habitat types in two clusters: (1) silty types as river mouths, shallow mud bottoms, deep channels and mangrove stands with high contents of organic matter and nutrients versus (2) non-silty types as seagrass beds and coral reefs with low contents of nutrients and organic matter. Median settling velocities of the silt loads varied from 0·6 m d 1 to 27 m d 1 . Experimentally determined susceptibility to resuspension identified a critical water content of 50%. 2002 Elsevier Science Ltd.

Dynamics of discharge, sediment transport, heavy metal pollution and Sábalo (Prochilodus lineatus) catches in the lower Pilcomayo river (Bolivia)

Abstract: The Pilcomayo river is one of the few intact natural river systems left on the South American continent. The high, largely natural, sediment loads of the river have led to the development of an alluvial fan system, which is still active. The river is currently retracting due to siltation of its bed, and in the near future the river is likely to abruptly change its course. There is a large difference in discharge between the wet and dry seasons. Pollution of the transported sediments by heavy metals from the mining district of Potosi is largely prevented by dilution of the toxic mining sludges with clean sediments derived from natural erosion processes. The Sabalo (Prochilodus lineatus) is a migrating fish which is very important for commercial fishing. The Sabalo grows up in the floodplains in the lower reaches of the river and starts its upstream migration at the end of the rainy season to spawn in the Andean foothill at the beginning of the next rainy season. Pollution does not seem to affect fish catches. Sabalo catches in a given year, however, do appear to depend strongly on the mean discharge in the three preceding years. Annual discharge is strongly influenced by the El Nino–Southern Oscillation (ENSO) phenomenon. Copyright © 2002 John Wiley & Sons, Ltd.

The ecological status of Lake Laguna de Bay, Philippines

Abstract: This article assesses the ecological status of Laguna de Bay using available published and unpublished information. The declining fishery productivity of the lake is the most glaring evidence of its stressed ecological state. This loss stems from numerous deleterious factors operating throughout the lake and its drainage basin. Phytoplankton community composition has drastically changed over the years and algal biomass has diminished in the presence of ample supplies of nitrogen and phosphorus. Light limitation due to high siltation rates in the perennially turbid lake whose Secchi depth is only 5 cm might be the primary limitation to photosynthesis. The problem of siltation in the lake is the result of deforestation in the watershed that heightened soil erosion rates. Trophic relationships are inadequately examined in Laguna de Bay, the biggest lake in Southeast Asia. High biological oxygen demand and high heavy metal levels in the lake water, sediments, and biota are evidence of excessive pollution. Hea...

Effects of Climate and Human Activities on the Ecosystem of Lake Baringo, Kenya

Abstract: Since the beginning of the last century, the Lake Baringo ecosystem has undergone several ecological changes. Most of the changes are a result of human activities within the catchment basin and changes in climatic conditions. Currently, the most significant limnological feature of the lake is its extreme turbidity with an average secchi disc reading of 9.5 cm. The lake water is brownish and muddy because of considerable siltation resulting from high rates of soil erosion caused by overgrazing by livestock and deforestation of the surrounding hills. Due to increased siltation, the bed of the lake in the open waters is virtually devoid of invertebrate life. Primary production in the open waters is very low as the only phytoplankton present are positively buoyant species such as Microcystis aeruginosa, Melosira granulata and Anabaena carcinalis. The depth of the lake has a significant effect on the transparency of the water (P<0.001), where transparency decrease with depth. Under normal conditions, Lake Baringo has low alkalinity, but with less rain, the lake has become more saline with an average conductivity of 660 μS cm−1 while the pH varies between 8.9 and 10.5. Five species of fish have been reported to occur in Lake Baringo: Oreochromis niloticus (Trewavas, 1983), Protopterus aethiopicus (Heckel, 1851), Glarias gariepinnus (Butchell, 1852), Barbus intermedius (Ruppell, 1836) and Labeo cylindricus (Peters, 1852). Presently, the species composition is dominated by Oreochromis (80.04%), Glarias (9.8%), and Protopterus (7.95%). Barbus rarely appear in the fisherman’s catches while Labeo has almost disappeared from the lake since the damming of the inflowing rivers which interfered with its breeding habits. Moreover statistical analysis has shown a significant relationship between fish yield and lake level changes (P<0.001).

Seasonal sediment transport pathways in Lirquen Harbor, Chile, as inferred from grain-size trends

Abstract: Bottom sediment samples were collected in June and December 1997 at 166 stations on a rectangular grid in a small port (Lirquen Harbor, BioBio Region, Central Southern Chile) facing siltation problems with a view to determining local seasonal sediment transport pathways through the application of three different methodologies based on grain-size trends. Measured winds and near-bottom currents together with hindcast wave allowed to establishing the influence of the prevailing meteorological and hydrodynamic conditions on local sediment circulation. The results suggest that transport of deep and shallow water sediments occur rarely under high-energy conditions. The current data suggest that tidal asymmetry would be an important agent of sediment transport in Lirquen Harbor. The sediment transport pathways inferred from grain-size trends are compared with the measured water circulation of the study area and sediment dispersal patterns on aerial photographs. The results yielded by the grain-size trend methodologies of Gao-Collins (1992) and Le Roux (1994b) indicate a possible seasonal variation in transport pathways agreeing with the prevailing meteo-hydrodynamic conditions, whereas the McLaren-Bowles (1985) approach does not show a significant difference. It is suggested that the latter methodology may represent transport on a spatial macroscale as opposed to the mesoscale patterns yielded by the other two techniques. Based on the results of the three grain-size trend methodologies, the observed current and wind data, the hindcast wave data and aerial photographs a conceptual model of net annual sediment transport is proposed for Lirquen Harbour.

Evaluation of the Siltation of River Taquari, Pantanal, Brazil, through 210Pb Geochronology of Floodplain Lake Sediments

Abstract: This work presents the 210Pb geochronology of seven bottom sediment cores, collected in three floodplain lakes located in the area of the middle Taquari River, Pantanal, Brazil. In five of them, a significant increase in the sediment mass deposition rate was observed, reflecting an increase of the sediment input to the Pantanal. Additionally, in order to validate the 210Pb results, the mercury content was determined for two sediment cores, showing that despite a constant concentration, the flux of Hg has increased due to an increase in the mass sedimentation rate. This increase can be attributed to the expansion of agricultural activity in the upper Taquari River during the last 25 years.

Phosphorus in a lowland calcareous river basin: a multiscale approach to understanding human impacts

Abstract: Lowland rivers in industrial countries such as the UK are seriously impacted by phosphorus from a variety of sources. Point sources include numerous sewage-treatment works; diffuse sources include a full range of agricultural activities from fertiliser application to intensive poultry and stock rearing. The scientific consensus is that the concentration of phosphorus is an important measure of eutrophication. The present study investigated the impact of point source effluents, together with physical impoundment by weirs, on the spatial heterogeneity of river bed sediment characteristics with emphasis on the forms and levels of phosphorus, within the catchment area of the River Wensum, Norfolk, UK. The within site variability of the sediment characteristics (total phosphorus, bioavailable phosphorus, calcium, iron and organic matter) was tightly linked to the river bed types. Total phosphorus in the sediment was extremely well correlated with total iron (r=0.93) suggesting a possible association between the two parameters. The weirs and impoundments impacted dramatically on the dynamics of in-stream flow which resulted in extensive problems of siltation in the River Wensum leading to high level of total phosphorus storage above the weir. This, combined with the increased concentration of total phosphorus in the water below the point sources, had the greatest impact on sediment phosphorus availability. Thus the ecology of the river may not follow expected downstream changes.

Wetlands and still waters

Abstract: INTRODUCTION Wetland and still water habitats are elements of a continuum that depend upon water storage and supply for their continued existence and ecological stability. If inputs of water are significantly reduced, or outputs are increased, the water balance will change and wetland ecology is likely to suffer. Many types of wetland have frequently been damaged by artificial drainage, in what has been termed ‘reclamation’ for economic exploitation such as agriculture, forestry or peat production (see, for example, Gilman, 1994). Also significant in many situations may be a change in water-storage capacity, either by manipulation of the ground surface (peat extraction) or by increased sedimentation caused by accelerated soil erosion as a result of human land-use changes. Cooke et al. (1993) indicated that 25% of lakes assessed in the USA could be described as ‘impaired’ and 20% as ‘threatened’ in some way. Often this was by nutrient enrichment, but other stresses included siltation and inappropriate water levels. Allen & Feddema (1996) suggest that wetland restoration involves actions aimed at improving damaged or deteriorating areas that were once healthy wetlands. In many countries, these natural wetlands are now only a fraction of their historical extent and have been identified as priority habitats for ecological restoration (e.g. Cooke et al. , 1993; Allen & Feddema, 1996; Tallis, 1998). This chapter relates to the fundamental principles that control the physical environment of wetlands and still waters. It concentrates upon fresh waters rather than estuarine or coastal wetlands.

Transportation and Adjustment of Different Grain Sized Sediment Along the Lower Yellow River under Typical Operation Modes of Sanmenxia Reservoir

Abstract: The degradation and aggradation of the Lower Yellow River are affected by the operation modes of the Sanmenxia Reservoir. Under the influences of clear water or water of low sediment concentration released from the reservoir, the channel of the Lower Yellow River was eroded and the sediment concentration was recovered, but the concentration of fine sediment recovered slowly in a long distance, while the coarse and medium sediment recovered fast in a rather short distance. When the reservoir was flushed, the Lower Yellow River was serious silted because of the low discharge, high sediment concentration and coarse sediment sluiced from the reservoir. The quantity of siltation accounted for 60%～70% of the incoming sediment load, in non\|flood season, the channel of the Lower Yellow River was eroded by clear water from the reservoir. The eroded sediment from the channel bed was relatively coarse in the reach upstream of Huayuankou. The eroded coarse and medium sediment accounted for 30%～40% respectively with the median size of 0 04mm. The erosive distance was increased with the increasing of discharge. After the Spring flood, the capabilities of sediment transport for different sized sediment were decreased because of the armouring of the composition of the channel bed, and the quantities of eroded sediment were also decreased correspondingly. When the reservoir was flushed in pre\|flood season, the grain size of flushed sediment was 0.005～ 0.042mm. The deposition mainly occurred in the reach upstream of Huayuankou. The quantities of deposition for different sized sediment were determined by the incoming sediment and were not related to the incoming discharge. The grain size also was a significant factor affecting the quantities of deposition.

Longshore sediment transport along the coast of boao harbour,hainan island

Abstract: beach sediment samples were collected and analyzed by sieving to obtain grain size parameters, i.e. mean grain size(μ), sorting coefficient(σ) and skewness(SK). Longshore sediment transport patterns were defined using grain size trend analysis and an empirical formula for longshore drift calculation. The result of GSTA indicates that sediments along coast section north of the Wanquan River mouth are moving landwards and silting up recently,while sediments along coast section south of the Wanquan River mouth are divided into southern and northern parts by a NNE-NE line,the northern part mainly goes from coast to sea and represents an erosion coast section,and the southern part moves from sea to coast and some sliting up occurs.The longshore drift shows that the net sediment discharges Section 1 to Section 3 can be 35 7×10 4, 32 7×10 4 and 33 3×10 4 m 3/a respectively. The erosion volume between Section 1 and Section 2 is 2 97×10 4 m 3/a, and the accumulation volume between Section 2 and Section 3 is 0 66×10 4 m 3/a. Difference in transport direction for the north of sand bar spit between the results derived from GSTA and the empirical formula is caused by various factors, such as inter annual and spatial variations in hydrodynamic conditions.

Application of ecohydrology in the Brahmaputra River

Abstract: Changes in hydro-geological pattern of the river Brahmaputra, due to changes in topography, altitude, precipitation, and soil conditions, has resulted in zonation of the river into five major types of habitats that influence the distribution of fish biota. The erratic nature of water discharge, high rates of erosion and siltation, and habitat destruction have negative impacts on the commercial fishery as shown by a gradual decline of almost all commercial varieties of fishes. The flood pulse is probably the strongest factor that regulates other limnological factors and faunal distribution. Between May and October, there are about two to four high floods and fish landings are closely related to this flood regime, while during the dry season fishing is mostly localized near the confluents of rivers and at river meanders. However, large-scale felling of trees in the catchment areas and construction of embankments along the river and major tributaries have resulted in the river becoming heavily silted and the connecting channels of floodplain lakes dammed. Consequently fishes and other aquatic mega fauna are deprived of adequate water cover. Use of small-meshed gears and certain other highly objectionable fishing methods have threatened the natural stock of fish fauna in the upstream of the river. Hydrology, water management and the management of human interferences play a crucial role in the conservation of biodiversity in the entire Brahmaputra ecosystem. The present paper therefore provides an ecohydrological insight into the Brahmaputra river system and proposes certain remedial measures for sustainable water management.

Representation on the function of siltation dam engineering in the upper and middle Yellow river

Abstract: Gully control engineering works for soil and water conservation in the upper and middle Yellow river involve siltation dam, key dam, small scale reservoir, check dam, farmland formed by livering flood water and other artificial farmland, of which dam and key dam are most effctive. This paper states its function for flood control through summing up its historical development and current implementation situation, then represents the phenomenon does not exist that sediment deposits bit by bit and all deposition is eroded for the siltation dam engineering at one time.

An Investigation-Study on the Erosion at Hak-Dong Gravel Beach

Abstract: The changes of sea bottom configuration, which may cause the coastal disasters, have beenconsidered as social problems. It is obvious that the beach deformation is atributable to the sediment transportasociated with erosion and siltation in coastal areas such esturies, chanel and harbors. The prediction methodand countermeasures for them, however, are not on the level of satisfaction, which indicates that make efortsshould be made on developing them. Groin was constructed at Hak-Dong gravel beach to embark ship at 196,as a result region of right of groin, severe erosion of beach is proceeding til now 19. In this study, based on thefield measurements, involved the one-line theory model which was selected for the prediction of shorelinechange to prepare coastal protection methods of Hak-Dong gravel beach. Author found that the storagedsediment estimation model by Sonu and Beek(1971) is useful model at the Hak-Dong gravel beach by the use oftopographical survey data from September, 1998 to September, 1999.

Acoustic Measurements of Suspended Sediments in Estuaries

Abstract: Sediment flux measurements are essential for estimating the environmental impact of erosion and depositional processes. In the coastal areas, sediment measurements are required to assess siltation of backwaters, sandbar formation across mouths of rivers, accretion and erosion of coastline from coastal structures, impacts of dredging operations, watershed loadings into the coastal zone and fate and transport of toxic chemicals. Sediments play a significant role in defining the interrelationships between the physical, chemical, biological and environmental factors. In rivers, lakes and estuaries, sediment is an important water quality indicator, not only as a pollutant but also as a transport or catalytic agent for other forms of pollution, especially toxics. The feasibility of measuring sediment loads over the entire cross-section in open channel flows, in particular estuaries, using acoustic measurements was studied.

Sustainability of Soil and Vegetation under Community Managed Forests: a Case Study from Southwest Bengal

Abstract: The major cause of degradation of biological diversity has been attributed to the effect of human activity. This also poses a serious threat to human development. It was also emphasized to recognize and foster traditional methods and the knowledge of indigenous people and their communities. This was the point where participation of communities in management of natural resources was felt necessary. The main agenda before our present study is to know to what extent the ecology of such jointly managed forests and ecorestoration activities have been able to reverse the process of depletion of soil as well as biological diversity. 2 Study site The present study site is the plateau tract in the southwestern side of Bengal and lies within 21 ° 36 N latitude and 85° 49 to 87 ° 46 E longitude. It is under Midnapore, Purulia, and Bankura administrative districts of West Bengal. Entire tract has undulating topography with old alluvium as parent material. Average annual rainfall of the entire lateritic belt varies from 1200 to 1400 mm. Maximum temperature during summer goes up to 47°C and in winter it comes down to 8°C. The spell of dry season varies 7 to 8 months in a year. The geological formation of the study has been described as older alluvium of subrecent to pleistocene. The alluvium appears to have been dislodged from the decomposed rock of adjacent territories and deposited in this area. The transported soil then underwent further weathering in the new environment. Joint Forest Management (JFM) of forests brought about visible quantitative and qualitative changes in the future of forest communities, to some extent, in this region. The region has led the JFM movement in India and at present has about 2,546 Forest Protection Committees (FPCs). In the present study comparison of some ecological parameters in between a managed (by the community) and unmanaged degraded land has been done. The site (Gopegarh) where a specific comparative study on different ecological aspects of managed and unmanaged stands was carried out is a highly undulated land in Kansabati catchment lying between 86°33′N latitude in the East Midnapore Forest Division, West Bengal. The region was originally covered with coppice sal (Shorea robusta) forests with associated species. As a consequence of mass felling and biotic interference about 174 hectares of land at Gopegarh were completely denuded with exposed laterites. The surface mineral horizon of the soil was almost absent due to heavy erosion prior to the plantation work because the site has complex slope with 5%—7% gradient towards north-eastern side and a sharp slope of 10%—12% gradient in south-eastern direction (towards Kansabati river). The site exhibited sheet erosion, rill erosion and gully erosion prior to the conservation activities. Three earthen dams of 95 m, 75 m and 50 m in length and 1 m, 2.55 m and 3.20 m in height were constructed at different locations during 1988—1989 to store water and to arrest siltation. Total area of three reservoirs is 0.77 ha. Plantation of Acacia auriculiformis was raised along with few Tectona grandis saplings during the rainy season of 1989 with a spacing of 2.5 m 2.5 m. At the first phase, plantation was raised in 90 ha of land and then in 1990 and 1991, 55 ha were covered. ‘V’ shaped trenches were dug in 90 ha of land at an interval of 20 m in the year 1989. During the time of study i.e. in the year 1994,

Calibration and up-scaling of an erosion model as a tool for farmers involvement to define alternative land use

Abstract: The Hilly Purple area of the Sichuan Basin has been degraded by constant soil erosion, which has reached to 3 035 t/km. Soil erosion has direct negative effects on the productivity of the land by loss of nutrients, water and soil. This loss of productivity affects the farmers income. Also, it increases the pollution and siltation of the Yangtze river, causing several problems downstream. The EROCHINUT project has started in 1998 with the overall objective to develop a new methodology to improve land and water management on farm and watershed level in the current socio-economic situation by integrated use of participatory and soil erosion and nutrient modeling techniques. By using a calibrated model, calibrated on a small catchment, and upscale the results base on slope classes, a reliable view of possible effects of alternatives on these features is achieved. These results are visualized on maps, and act as support tools to discuss with farmers and policy makers on the feasibility and possibilities of alternative land use.

Effects of Hill Land Development and Soil Erosion on Sedimentation and Water Resources in Malaysia

Abstract: In Malaysia, water quantity and quality as well as siltation of river beds are closely connected with hill land development, soil erosion and sedimentation. Gradual depletion of developable lowland has resulted in the development of hill land, which located on the upstream of drainage basins, is extremely sensitive to human-induced environmental changes. Even small changes caused by forest clearance could lead to severe damage on natural systems such as flora, fauna, climate, hydrology and soils. Rapid development of the foothills, slopes and hill tops since the 1970s, have resulted in depletion of forest, destruction and deterioration of water catchments, changing micro-climatic elements, endangering of wild life, high rates of soil erosion, increased incidence of landslides and rockfalls, high rates of sedimentation leading to rapid siltation and reduced capacities of rivers leading to increased frequencies and magnitudes of downstream flooding, and the pollution of river water. Much of such negative impacts are also due to the disparate and uncoordinated nature in which a large number of government agencies manage drainage basins. There is a need for all drainage basins to be managed in an integrated manner in order to control hill land development and the associated impacts.

A Statistical Probability Model for Calculating Siltation of Open Channel on a Silt-sandy Beach

Abstract: A Statistical probability model for calculating deposition amount is proposed on the basis of depositing features of the open channel on a silt sandy beachDeposition amount of the open channel of a harbor due to several times of gale during the construction is calculated with the modelAnd throngh comparison,the calculated results are in good agreement with that measured from the fieldTherefore,it's considered that the model is suitable for constructional calculationAnd finally,statistical characteristics of siltation in open channel is analyzed from the field data of the harbor

GIS supporting study on calculation of the amount of siltation and erosion in mouth bars of the Changjiang Estuary

Abstract: Supported by GIS, 10 pieces of charts of the Changjiang Estuary from 1842 to 1997 are studied. Digital elevation model of the Changjiang Estuary is established with Kriging gridding method to research evolution of channel, change of coasts, formation and evolution of islands in mouth bar area with different points of view: transverse sections, longitudinal profiles, plane change, etc. Furthermore channel-fill volumes are calculated andcalculations of amount of deposition and erosion in different scopes between different years are conducted. The calculated results show that the evolution of mouth bar area of the Changjiang Estuary was complex in near 155 a (1842~ 1997): deposition has its trend, but the speeds of deposition in different terms are different and erosion occurs place in a few terms which mainly are related to dynamic conditions. About 3.81 Gt of sediment was deposited between 1842 and 1997, with average annual deposition rate of 24.6 Mt which amounts to 5% of sediment form the Changjiang River. Jiuduansha , Hengsha and its east beach, and east beach of Chongming Island are the main positions of siltation and the current North Passage is the main position of erosion. In addition, there is slight erosion in the upper part of the North Channel and part of the South Passage. Together, the area of erosion is limited and it only amounts to 21.4% of total study area.

A stochastic sediment supply model for a semi-arid landscape

Abstract: We investigated the surficial processes that deliver sediment from hillslopes into channels in a mediterranean landscape and determined how these processes are controlled by climate and landscape characteristics (e.g. topography, vegetation). Watersheds in semi-arid regions of the United States are subject to a variety of disturbances, including grazing, fires, and vegetation cover changes and, while the consequences of sediment loading are well documented, presently our ability to predict the spatial and temporal pattern of delivery is poor. The processes that we have investigated are: shallow landslides, overland flow, dry ravel, and bioturbation. Through field experiments and monitoring, we have developed physically-based transport equations for each individual process. These transport equations are used as the governing equations for a computer model, driven by random sequences of rainstorms and fires, that predicts the spatial and temporal patterns of sediment delivery. As downstream problems become more closely linked to watershed conditions and perturbations, this type of fundamental research is relevant to issues such as the health of riverine ecosystems and the siltation of reservoirs. We anticipate that our fieldwork and modeling results will help land managers estimate the influx of sediment from surface processes according to different land-use practices.

Sedimentological considerations for predictive modelling

Abstract: Predicting the trends in siltation within an estuary from the record of siltation is of relevance to harbour management. Sampling and profiling within Goteborg Harbour has revealed a highly dynamic environment; the estuary is a zone not only of accumulation but also of cleansing and release. An evaluation of GIS modelling approaches to prediction is presented, incorporating multiple criteria applied to spatial prediction; zinc concentration within the near-surface sediment profile is used for illustrative purposes.