Introduction to Collection System Flow and Rainfall Monitoring (Part 1)
Flow and rainfall monitoring is a crucial aspect of managing water resources in municipalities. Flow and rainfall monitoring involve measuring the natural occurrence of precipitation as well as human-related inputs (i.e., sewage in wastewater systems) and the resulting flow conditions in collection systems. In this blog post, we will delve into the importance of flow and rainfall monitoring, the typical flow patterns in a wastewater system, the importance of understanding level of service, and the types of flow monitoring programs that municipalities can choose from.
Why Is Flow and Rainfall Monitoring Important?
Flow and rainfall monitoring is essential for ensuring that wastewater and stormwater is collected and treated appropriately while helping to understand system capacities and prevent adverse effects such as flooding. Ultimately, flow and rainfall monitoring helps municipalities understand and analyze the long-term effects of rainfall and storms, assess their infrastructure, and improve the value they deliver to their customers – the residents that live there.
Understanding Typical Flow Patterns in a Wastewater Systems
The typical flow pattern in a wastewater system is impacted by human water use and usually has a repeatable diurnal pattern. Patterns vary based on land use type but typically have two peak times (morning and evening), and differing weekday versus weekend flow patterns. Sewer system capacity analyses must take into account these variables, among others, in order to be carried out accurately.
This understanding is important in order to ensure that the system is designed and built to the appropriate performance level and that it can accommodate future growth and changes in climate.
Collection System Level of Service
It is technically and financially impossible to design and build a collection system that can accept storms of all sizes. Instead, the acceptable level of service needs to be determined, and collection systems need to be built and maintained to sustain the prescribed performance level.
For example, one municipality in Ontario may have storm collection systems designed with a catch basin density that can capture a 5-year design storm, while another may collect up to the 100-year design storm. The amount of investment in building and maintaining these two different systems will vary significantly based on the level of service prescribed.
The level of service needs to consider the municipalities ability to pay for an increased level of service, customer needs (who is benefitting and how much?), and acceptable risk levels. Flow and rainfall monitoring can help to understand if a system is performing up to its prescribed level of service.
Types of Flow Monitoring Programs
Municipality size often determines the size and extent of flow and rainfall monitoring programs, with larger municipalities typically maintaining some permanent monitoring sites and supplementing them with temporary programs as necessary.
Municipalities can choose from a variety of flow monitoring programs, including permanent monitoring locations, temporary monitoring stations used for inflow and infiltration studies, model updates/calibration, capacity assessments, understanding bypass pumping needs for construction, etc.
Most municipalities should have a handful of permanent monitoring stations, especially at critical points in the collection system, to ensure the systems are working properly and to plan for future infrastructure needs.
Why Choose Civica?
Flow and rainfall monitoring is a vital aspect of managing water resources in municipalities. It enables the understanding of water events and their impact on collection systems, and helps municipalities and developments protect sewage assets, improve value delivery, and prevent flooding.
In this blog post, we have discussed the importance of flow and rainfall monitoring, the typical flow patterns in a sanitary sewer, the level of service offered by monitoring programs, and the types of flow monitoring programs that municipalities and developments can choose from.
For more information on flow and rainfall monitoring, please contact Civica today.
Learn More at:
Impacts of Existing Storm Drainage Design Standards in Ontario on Sanitary System Capacity (Part 1)
Impacts of Existing Storm Drainage Design Standards in Ontario on Sanitary System Capacity (Part 2)
About Matthew Malone
Matthew Malone has accumulated a wealth of experience in the areas of wastewater and stormwater capacity assessment and management, with a high level of expertise in capacity management, stormwater management, flow monitoring, and inflow...
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