Response of sediment concentration and load to removal of juniper woodland and subsequent establishment of grasslands – A paired experimental watershed study

CATENA ◽  
2022 ◽  
Vol 209 ◽  
pp. 105816
Author(s):  
Yu Zhong ◽  
Rodney E. Will ◽  
Tyson E. Ochsner ◽  
Adrian Saenz ◽  
Lan Zhu ◽  
...  
Keyword(s):  
Sediment Concentration ◽  
Juniper Woodland

Neural networks approached for modelling river suspended sediment concentration due to tropical storms

2013 ◽  
Vol 11 (4) ◽  
pp. 457-466
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Time Series Data ◽  
Water Discharge ◽  
Sediment Concentration ◽  
Series Data ◽  
Generalized Regression Neural Network ◽  
Event Based

Artificial neural networks are one of the advanced technologies employed in hydrology modelling. This paper investigates the potential of two algorithm networks, the feed forward backpropagation (BP) and generalized regression neural network (GRNN) in comparison with the classical regression for modelling the event-based suspended sediment concentration at Jiasian diversion weir in Southern Taiwan. For this study, the hourly time series data comprised of water discharge, turbidity and suspended sediment concentration during the storm events in the year of 2002 are taken into account in the models. The statistical performances comparison showed that both BP and GRNN are superior to the classical regression in the weir sediment modelling. Additionally, the turbidity was found to be a dominant input variable over the water discharge for suspended sediment concentration estimation. Statistically, both neural network models can be successfully applied for the event-based suspended sediment concentration modelling in the weir studied herein when few data are available.

APPLICATION OF ACOUSTIC METHODS IN RESEARCHES OF THE BOTTOM SEDIMENT DYNAMICS

2018 ◽  
Author(s):  
Б. Дивинский ◽  
B. Divinskiy ◽  
И. Грюне ◽  
I. Gryune ◽  
Р. Косьян ◽  
...  
Keyword(s):  
Suspended Sediment ◽  
Sediment Concentration ◽  
Irregular Waves ◽  
Single Frequency ◽  
Contactless Measurement ◽  
Measurement Means ◽  
Uniform Field ◽  
Wave Flume ◽  
Acoustic Methods ◽  
Back Scattering

Acoustic methods belong to contactless measurement means, possess high spatial and time resolution. Thus, the use of multifrequency allows directly profile both concentration and granulometric structure of the suspended substances. In 2008 in the Big Wave Flume (Hanover, Germany) by efforts of the Russian and German scientists there have been carried out the experiment on studying the bottom material suspension laws under the influence of irregular waves. The Aquascat 1000 acoustic back scattering sensor (ABS) manufactured by British company Aquatec (www.aquatecsubsea.com), equipped by a three-frequency transmitter with frequencies 1,0, 2,0 and 3,84 MHz, has been set on distance of 0,75 m from the bottom and 111 m from wave generator at the total depth of 3,2 m. Several dozen series of measurements at various parameters of surface waves have been carried out. The general picture of suspension is so that the external dynamic influence (currents, wave movements, turbulence, gravitation forces) creates a non-uniform field (gradient) of the suspended particles and in most cases due to this the average size of particles undergoes to the spatial-time variations. For this reason while defining the mass concentration of suspended sediment, using the single frequency transmitter there is necessity for numerous definition of the suspension granulometric structure what by isn’t always possible. If two and more frequencies are used the observed results comparison can give the information on average diameters of particles and on that basis the calculation of suspended sediment concentration is possibleLet's emphasize the basic advantages of back scattering acoustic gauges usage: – Obtaining the particles sizes and concentration distribution profiles is possible; – The initial granulometric structure of bottom sediments can be unknown (at use of several frequencies). The following can be referred to some lacks of the device: – The system should be calibrated in laboratory conditions; – In a positive feedback conditions the iterative computing process can converge to zero or to infinity. In this case experiments with a variation of carrier frequencies chosen for the analysis allow partially solve the problem (say experiments with different frequencies pairs, as 2/1 of MHz or 4/2 MHz).

Relationships Between Soluble and Sediment Nutrient Losses, Land Use and Types of Soil in Agricultural Watersheds

1977 ◽  
Vol 12 (1) ◽  
pp. 121-134 ◽  
Author(s):  
G.H. Neilsen ◽  
A.F. Mackenzie
Keyword(s):  
Land Use ◽  
Inorganic Nitrogen ◽  
High Surface ◽  
Sediment Concentration ◽  
Chemical Oxidation ◽  
Nutrient Loss ◽  
Potassium Sulfate ◽  
Agricultural Watersheds ◽  
Nutrient Losses ◽  
Calcium Magnesium

Abstract Seven agricultural watersheds in southwestern Quebec and southeastern Ontario, ranging in area from 2,000 to 20,000 hectares, were monitored systematically during 1973–75 for soluble inorganic nitrogen, total soluble phosphorus, calcium, magnesium, potassium, sulfate-sulfur, chemical oxidation demand, discharge, suspended sediment concentration, sediment Kjeldahl nitrogen, Bray extractable phosphorus, and ammonium acetate extractable calcium, magnesium and potassium. For 1974–75, annual Kg/ha, loss rates were calculated for the soluble and sediment associated nutrients. Losses varied with nutrient and watershed, with volume of runoff being an important control of nutrient loss variation. Significant amounts of SO4−S in precipitation were suggested by an average watershed soluble N:P:S loss ratio of 10:1:92. Sediment nutrient losses were especially important for N and P, comprising over 40% of their total loss. The importance of spring snow-melt runoff was demonstrated by the high proportion of all nutrients lost at this time. Correlations of nutrient loss, land use and soils suggested that certain land uses resulted in increased stream nutrient losses while increased watershed area of soils with a high surface runoff potential was particularly conducive to increased soluble nutrient and sediment losses.

The Design of Water Intake System and Analysis of Water Quality Conditions of the Regional Energy System of Complex River Water Source Heat Pump

2015 ◽  
Vol 8 (1) ◽  
pp. 38-42
Author(s):  
Pengfei Si ◽  
Xiangyang Rong ◽  
Angui Li ◽  
Xiaodan Min ◽  
Zhengwu Yang ◽  
...  
Keyword(s):  
Water Quality ◽  
Energy Consumption ◽  
River Water ◽  
Heat Pump ◽  
Water Intake ◽  
Water Source ◽  
Energy System ◽  
Sediment Concentration ◽  
Regional Energy ◽  
Heat Pump Unit

As a realization of the energy cascade utilization, the regional energy system has the significant potential of energy saving. As a kind of renewable energy, river water source heat pump also can greatly reduce the energy consumption of refrigeration and heating system. Combining the regional energy and water source heat pump technology, to achieve cooling, heating and power supply for a plurality of block building is of great significance to reduce building energy consumption. This paper introduces a practical engineering case which combines the regional energy system of complex river water source heat pump, which provides a detailed analysis of the hydrology and water quality conditions of the river water source heat pump applications, and discusses the design methods of water intake and drainage system. The results show that the average temperature of cold season is about 23.5 °C, the heating season is about 13.2 °C; the abundant regional water flow can meet the water requirement of water source heat pump unit; the sediment concentration index cannot meet the requirement of river water source heat pump if the water enters the unit directly; the river water chemistry indicators (pH, Cl-, SO42-, total hardness, total iron) can meet the requirement of river water source heat pump, and it is not required to take special measures to solve the problem. However, the problem of sediment concentration of water must be solved.

scholarly journals Getting information on suspended sediments in a large river from acoustic backscatter

2018 ◽  
Vol 40 ◽  
pp. 04017
Author(s):  
Adrien Vergne ◽  
Céline Berni ◽  
Jérôme Le Coz
Keyword(s):  
Suspended Sediment Concentration ◽  
Spatial Information ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Large River ◽  
Acoustic Backscatter ◽  
Qualitative Information ◽  
Sediment Size ◽  
The Common

There has been a growing interest in the last decade in extracting information on Suspended Sediment Concentration (SSC) from acoustic backscatter in rivers. Quantitative techniques are not yet effective, but acoustic backscatter already provides qualitative information on suspended sediments. In particular, in the common case of a bi-modal sediment size distribution, corrected acoustic backscatter can be used to look for sand particles in suspension and provide spatial information on their distribution throughout a river crosssection. This paper presents a case-study where these techniques have been applied.

Sign in / Sign up

Export Citation Format

Share Document