Analysis and calculation of sediment scouring rate at different locations of storm sewer

To explore the migration differences of sediments at the front, middle, and end sections of a storm sewer when scoured by water, and further evaluate the pollution load, the scouring process of sediments at different locations of a storm sewer was simulated and mathematical models were built to calculate the scouring rate. Results show that scouring rate is affected by sediment particle size, pipeline slope, sediment thickness, and water flow velocity. As the slope increased, scouring rate at the end section increased more obviously. The scouring rate at the front section slightly decreased with increasing sediment thickness, but opposite trends were observed at the middle and end sections. When the particle size (0.33 mm–0.83 mm) and flow velocity (0.15 m/s–0.65 m/s) increased within their ranges, scouring rate increased across all three locations. Models for calculating scouring rate were established via two data fitting. The calculated values were compared with measured values at a scouring time of 1 min. Under different particle sizes, the difference between the calculated and measured values at front, middle, and end sections were in the ranges of −0.63% to 0.63%, −0.01% to 0.02%, and −0.13% to 0.16%, respectively, all of which showed good consistency.

A Comprehensive Planning Framework for Urban Inland Oil Spill Management

Oil spills occurring on land have accounted for at least one third or over 24,000 of all land spills (approximately 76,000) of various substances reported in Ontario from 1988 to 2013. The objective of this research was to develop a comprehensive planning framework for urban inland oil spill management encompassing all three stages of spill management: (1) prevention, (2) control and (3) response. An inland oil spill database was developed and the source of each spill was analyzed. Preliminary analyses determined that approximately 46 % of spills occur at fixed locations (stationary spills), 21 % of spills involve moving vehicles (transportation-related), 13 % involve moving vehicle accidents (transportation-related accidents) and 20 % were categorized as other kinds of spills. Sub-databases were developed for both stationary and transportation-related spills which include numeric and non-numeric data variables. Hot spot analyses (optimized version) were performed on a subset of transportation-related spills to develop a highway spill model. The highway spill model illustrates that the majority of highway spills (75 %) occur at interchanges and the remaining spills occur either on the highway (8 %) or at unknown locations (17%). A macro program was developed to simulate future spill events based on historical spill events of gasoline spills within the case study area. The variables under study were fitted with distributions and Monte Carlo or Iman Conover methods were used to generate simulation results spreadsheets of spill series data based on the fitted distributions. The final macro program generated 30,000 simulation results spreadsheets and compiled the results in an aggregate spreadsheet. Descriptive statistics of the numeric variables were calculated and used to recommend spill management strategies. A simulation results spreadsheet with predicted spill records was used to develop a Geographic Information Systems (GIS) model to delineate spill pathways and calculate travel-time for overland flow and channel flow within the storm sewer system (geometric network). The model delineates the overland spill path and traces the spill path through the storm sewer network. The travel-time for each type of path is calculated and can be summed to determine the total travel-time for each predicted spill. Keywords: inland oil spill, comprehensive planning framework, spill management, prevention, control, response, stationary, transportation-related, hot spot analysis, macro program, Monte Carlo, Iman Conover, simulation, GIS, travel-time, spill path, geometric network

Modelling of methoprene concentration at storm sewer outfall

The objective of this report is to compare the predicted concentration of methoprene, a larvicide used in the City of Toronto to control the widespread of West Nile Virus by suppressing mosquito growth, at storm sewer outfall during a typical year rainfalls (1980 rainfalls) with the Interim Provincial Water Quality Objectives (IPWQO). The methoprene that is under investigation in this report is in form of ingot. Extending from an existing spreadsheet-based model that simulates the methoprene concentration within two monitored catch basins in the Newtonbrook sewershed of North York, methoprene concentration at the sewer outfall during the 1980 rainfalls is predicted by linear projection upon calibration of the model with the methoprene mass at the outfall measured in year 2005. Results show that predicted methoprene concentration at outfall exceeds the IPWQO in six days out of the one-hundred-day period. It is recommended that to better mimic the actual situation, traveling time effect and sensitivity analysis on catch basin sump volume be included in future study.

Modelling of methoprene concentration at storm sewer outfall

The objective of this report is to compare the predicted concentration of methoprene, a larvicide used in the City of Toronto to control the widespread of West Nile Virus by suppressing mosquito growth, at storm sewer outfall during a typical year rainfalls (1980 rainfalls) with the Interim Provincial Water Quality Objectives (IPWQO). The methoprene that is under investigation in this report is in form of ingot. Extending from an existing spreadsheet-based model that simulates the methoprene concentration within two monitored catch basins in the Newtonbrook sewershed of North York, methoprene concentration at the sewer outfall during the 1980 rainfalls is predicted by linear projection upon calibration of the model with the methoprene mass at the outfall measured in year 2005. Results show that predicted methoprene concentration at outfall exceeds the IPWQO in six days out of the one-hundred-day period. It is recommended that to better mimic the actual situation, traveling time effect and sensitivity analysis on catch basin sump volume be included in future study.

A Comprehensive Planning Framework for Urban Inland Oil Spill Management

Oil spills occurring on land have accounted for at least one third or over 24,000 of all land spills (approximately 76,000) of various substances reported in Ontario from 1988 to 2013. The objective of this research was to develop a comprehensive planning framework for urban inland oil spill management encompassing all three stages of spill management: (1) prevention, (2) control and (3) response. An inland oil spill database was developed and the source of each spill was analyzed. Preliminary analyses determined that approximately 46 % of spills occur at fixed locations (stationary spills), 21 % of spills involve moving vehicles (transportation-related), 13 % involve moving vehicle accidents (transportation-related accidents) and 20 % were categorized as other kinds of spills. Sub-databases were developed for both stationary and transportation-related spills which include numeric and non-numeric data variables. Hot spot analyses (optimized version) were performed on a subset of transportation-related spills to develop a highway spill model. The highway spill model illustrates that the majority of highway spills (75 %) occur at interchanges and the remaining spills occur either on the highway (8 %) or at unknown locations (17%). A macro program was developed to simulate future spill events based on historical spill events of gasoline spills within the case study area. The variables under study were fitted with distributions and Monte Carlo or Iman Conover methods were used to generate simulation results spreadsheets of spill series data based on the fitted distributions. The final macro program generated 30,000 simulation results spreadsheets and compiled the results in an aggregate spreadsheet. Descriptive statistics of the numeric variables were calculated and used to recommend spill management strategies. A simulation results spreadsheet with predicted spill records was used to develop a Geographic Information Systems (GIS) model to delineate spill pathways and calculate travel-time for overland flow and channel flow within the storm sewer system (geometric network). The model delineates the overland spill path and traces the spill path through the storm sewer network. The travel-time for each type of path is calculated and can be summed to determine the total travel-time for each predicted spill. Keywords: inland oil spill, comprehensive planning framework, spill management, prevention, control, response, stationary, transportation-related, hot spot analysis, macro program, Monte Carlo, Iman Conover, simulation, GIS, travel-time, spill path, geometric network

Modelling the fate of a larviciding chemical, methoprene, at drainage systems

With the recent occurance of mosquito-borne WEst Nile Virus (WNV) in Canada, the City of Toronto and the surrounding municipalities have undertaken the larviciding program to control mosquitoes during the summer months. The larviciding chemical, methoprene, can be incorporated in clay pellets or chalks which sink to the bottom of a catch basin sump. The main concern is whether or not the methorprene pellets or chalks will still be in a catch basin sump or to be flushed out during storm events. The objective of this thesis is to develop a water quality model, which is based on surface hydrology, mass balance and hydraulic characteristics of flushing at catch basin, in order to predict residual concentration of methoprene at catch basins and storm sewer outfalls. The findings of the research and all information from other contributing parties are expected to contribute to our understanding of the fate of methoprene at catch basins and storm sewer outfalls and improve the mosquito larviciding program in the Greater Toronto Area.