scholarly journals Impact of Climate Change on Metal and Suspended Sediment Concentrations in Urban Waters

2020 ◽  
Vol 8 ◽  
Author(s):  
Paul Frogner-Kockum ◽  
Gunnel Göransson ◽  
Marie Haeger-Eugensson
Keyword(s):  
Climate Change ◽  
Suspended Sediment ◽  
Contaminant Transport ◽  
Dry Period ◽  
Short Term ◽  
Impact Of Climate Change ◽  
Suspended Sediment Concentrations ◽  
River Loads ◽  
Metal Contaminant ◽  
The Impact

In order to study the impact of climate change on metal contaminant transport in urban waters and its relevance for water quality, we have analyzed variations in metal- and suspended sediment concentrations (SSC) in three urban rivers and one small creek in the Gothenburg region during various hydrological events such as spring flood, dry period, and wet period. To interpret river loads of metals and SSC we have furthermore followed meteorological trends since 1961 and additionally calculated future trends for the Gothenburg region, located on the west coast of Sweden. During periods of a short-term increase in precipitation we found an increased particle bound metal transport in urban watercourses of the Göta Älv River. In addition, a correlation between studied parameters indicates that surface runoff from brownfields most likely is the main source to the increased transport of pollutants in river systems rather than re-suspension of polluted river sediment.

Temporal variability of annual suspended sediment yield estimates and their uncertainties

2021 ◽  
Author(s):  
Aron Slabon ◽  
Thomas Hoffmann
Keyword(s):  
Suspended Sediment ◽  
Sediment Yield ◽  
Temporal Variability ◽  
Catchment Area ◽  
Sediment Load ◽  
Sampling Interval ◽  
Suspended Sediment Transport ◽  
River Rhine ◽  
The Impact ◽  
Annual Sediment

<p>Suspended sediment contributes to the vast majority of the annual sediment load transported by rivers to the global oceans. At the same time, this large fraction is transported just in a fraction of time. Towards achieving sustainable sediment management and healthy fluvial systems, identifying the impact of the temporal variability on annual load estimates becomes indispensable in order to reduce uncertainties.</p><p>We aim to estimate the temporal variability of suspended sediment transport and the uncertainty of annual suspended sediment loads. Our approach is based on high-resolution time series (15 min sampling interval) of discharge and suspended sediment concentration (SSC) at four monitoring stations with different degrees of discharge variability. The quantification of the variability of discharge and sediment yield is achieved through the exceedance time. The uncertainty of the annual sediment load is estimated using a bootstrap approach. We assess the impact of the sampling interval and link the optimal sampling interval to different SSC-variability. Further, the impact of rating parameters on the uncertainty of annual loads is investigated.</p><p>Our results indicate an increase in SSC-variability with decreasing discharge, leading to a negative relationship with the contributing catchment area. The 80 % exceedance times for the annual sediment load range from less than 10 % for the river Ammer (catchment area 608 km²) between 10 – 20 % for the rivers Ilz (765 km²) and Moselle (27 088 km²) to more than 40 % for the river Rhine (109 806 km²). Simultaneously, the variability increases with a decrease in sampling frequency. Our preliminary results indicate a negative exponential relationship between exceedance time and uncertainties in annual load estimates. This relationship can be used to estimate the uncertainty of annual loads estimated based on low frequency sediment sampling at the continental to global scale.</p>

scholarly journals Appraising the Impact of Naraj Barrage on Sedimentation of Chilika Lagoon; the Soft Computing Model for Prediction

2020 ◽  
pp. 31-41
Author(s):  
Siba Prasad Mishra ◽  
Ananta Charan Ojha
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Learning Algorithm ◽  
River System ◽  
Suspended Sediment Transport ◽  
Chilika Lagoon ◽  
Surrounding Environment ◽  
Ensemble Machine Learning ◽  
The Impact ◽  
Total Sediment

Estimation of suspended sediment transport in a catchment area is very important to manage water resources, construction of dam and barrage, as well as to protect the surrounding environment. The daily monsoon sediment and flow were observed physically and quantity of total sediment input by the two major rivers of the south Mahanadi deltaic rivers to Lagoon Chilika were calculated during pre Naraj barrage (FY 2000 to 2003) and post Naraj Barrage period (FY’s 2004, 2012, 2013) establishing an observatory in the rivers the Daya and the Bhargovi.[b] The non-linear complex relationship between quantity of suspended sediment transport and volume of river-discharge inflicts challenge to the estimation process. In this paper, two southern-most distributaries, the Daya and the Bhargovi of the Mahanadi River System which flow into Chilika lagoon are studied. Random Forest, an ensemble machine learning algorithm is used to estimate the transport of sediment by these two distributaries using predictive modeling. Predicted figures based on the gathered data from these distributaries during pre-barrage period 2000-2003 have been compared with the observed data gathered in post-barrage years 2004, 2012 and 2013. Comparative data suggests that the construction of Naraj barrage has significantly reduced the concentration of sediment influx into Chilika lagoon while controlling the discharge through effective barrage management.

Climate change impact on NW Shelf seabed evolution and its implication for offshore pipeline design

2008 ◽  
Vol 48 (1) ◽  
pp. 171 ◽  
Author(s):  
Fangjun Li ◽  
Cedric Griffiths ◽  
Tristan Salles ◽  
Chris Dyt ◽  
Ming Feng ◽  
...  
Keyword(s):  
Climate Change ◽  
Sediment Transport ◽  
High Energy ◽  
Change Scenario ◽  
Seabed Sediment ◽  
Impact Of Climate Change ◽  
Offshore Pipeline ◽  
Pipeline Design ◽  
The Impact

In this paper, the impact of climate change on seabed sediment transport in the north-western region of the Australian Exclusive Economic Zone (EEZ) has been investigated by a state-of-the-art numerical sediment transport model, Sedsim. It links the environmental forces and seabed response into a dynamic sedimentation system. Although numerical implementation of some forcing and responses is approximate, it is a significant step forward in understanding the nature of potential long-term seabed changes as well as in evaluating the likely impact of climate change on the northwest Australian continental shelf. It was found that: the modelled high-energy climate change scenario produced 17% and 38% increases on total volumes of seabed transport in the northern and southern part of the Australian northwest region respectively; the Indonesian ThroughFlow (ITF), the Leeuwin Current (LC) and high energy waves (associated with tropical cyclones) play the most important roles in large-scale long-term evolution of the NW seafloor; offshore pipeline design could usefully incorporate the changed risk profiles due to long-term non-stationarity of climate-derived forcing processes.

scholarly journals Modeling Hydro-Dynamics in a Harbor Area in the Daishan Island, China

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 192 ◽  
Author(s):  
Yuting Li ◽  
Zhiyao Song ◽  
Guoqiang Peng ◽  
Xuwen Fang ◽  
Ruijie Li ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Flow Velocity ◽  
Suspended Sediment ◽  
Hydrodynamic Model ◽  
Transport Model ◽  
Measurement Data ◽  
Cross Flow ◽  
Sediment Concentration ◽  
Suspended Sediment Transport ◽  
The Impact

This study presents an incorporation and application of a two-dimensional, unstructured-grid hydrodynamic model with a suspended sediment transport module in Daishan, China. The model is verified with field measurement data from 2017: water level, flow velocities and suspended sediment concentration (SSC). In the application on the Daishan, the performance of the hydrodynamic model has been satisfactorily validated against observed variations of available measurement stations. Coupled with the hydrodynamic model, a sediment transport model has been developed and tested. The simulations agreed quantitatively with the observations. The validated model was applied to the construction of breakwaters and docks under a different plan. The model can calculate the flow field and siltation situation under different breakwater settings. After we have analyzed the impact of existing breakwater layout schemes and sediment transport, a reasonable plan will be selected. The results show that the sea area near the north of Yanwo Shan and Dongken Shan has a large flow velocity exceeding 2.0 m/s and the flow velocity within the isobath of 5 m is small, within 0.6 m/s. According to the sediment calculation, the dock project is feasible. However, the designed width of the fairway should be increased to ensure the navigation safety of the ship according to variation characteristics of cross flow velocity in channel.

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