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Sediment Study in Storm Sewer Catchbasins and Submerged Pipes
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- Author / Creator
- Tang, Yangbo
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Studying sediment in storm sewer systems is important for their operation and design of storm sewer systems. This thesis presents a literature review on the existing work on sediment in storm sewer and the current results of experimental studies on sediment motion and settlement in storm sewer catchbasins and submerged pipes. Sediment may pollute downstream water, adversely impacting aquatic life, source waters for drinking water supplies, and recreational uses. Sedimentation in sewer pipes may cause sewer blockage problems, reduce the flow area and cause surcharged flows and urban flooding. Storm sewer sediment characteristics reported in the literature include storm sewer sediment sources, classification based on sediment sizes, particle median size surveys, particle size distribution investigations, particle settling velocity calculations, and the particle pollution potentials. During the rainfall, the sediment moves from catchment surface into storm sewer catchbasins, and then enters storm sewer pipes. Thus, related literature on sediment loading estimation and sediment movement in sewer pipes is included. A number of factors need to be considered in estimating sediment loading: sediment buildup, rainfall intensity, rainfall energy, runoff rate, sediment sizes, and land surface characteristics. Sediment movement includes three parts: erosion, transport and deposition. In terms of sediment blockage problems, sediment critical erosion velocity and sediment self-cleansing velocity are discussed in detail. Also, a collection of different experiments about sediment movement in storm sewers is presented. A laboratory experiment was conducted on catchbasins to predict sediment removal efficiency under different conditions (including flow rate, particle size, and inlet control device). For Calgary’s catchbasins, particles with d50 of 1800 µm can be easily captured, while smaller particles of 62 µm d50 can be easily flushed out of catchbasins, even at low flow discharge. An equation is developed for predicting sediment capture efficiency in a catchbasin for different particle sizes and flow rates. The proposed equation can be used for catchbasin design. Consequently, a laboratory experiment about sediment movement in submerged pipes was completed. According to observations, the development of deposition appears to have two stages: the rapid developing stage (sand deposit grows both in height and in length directions), and the equilibrium developing stage (sand deposit only grows in the length direction). With respect to sediment transport capacity, it can be described by an equation consisting of a sediment transport parameter, bed shear intensity, and relative bed thickness.
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- Subjects / Keywords
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- Graduation date
- Fall 2016
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- Type of Item
- Thesis
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- Degree
- Master of Science
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- License
- This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.