The potential for climate change to increase the frequency and severity of floods highlights the need for municipalities to apply integrated approaches to Stormwater Management.
The Climate Change Conundrum
In 2011, while the Eastern and Western Cape were threatened by drought, flooding associated with El Niño affected 24 municipalities across all other major provinces of South Africa. According to the National Disaster Management Centre, 40 people had lost their lives and 6000 were displaced. Costs associated with infrastructure repair, such as loose pumps and motors, as well as the flooding of pump stations, exceeded R20 million.1 In the Limpopo Province, water borne diseases such as cholera have historically followed in the wake of such flooding.2
The recent floods in Tshwane and Johannesburg in 2016 again displayed the strategic challenge stormwater poses to South African municipalities. In Gauteng, where rainfall and flooding has an impact on acid mine drainage,3 the management of stormwater is of particular importance.
Climate change has the potential to increase the frequency and severity of floods and droughts. On the one hand, increased volumes and flow rates of stormwater come with associated risks such as damage to infrastructure assets, disaster management interventions, the loss of livelihoods and property as well as the threat of waterborne diseases. On the other hand, the effective management of stormwater in relation to the urban water cycle can contribute to more effective Water Services Planning and Water Demand Management.
Why the need for an Integrated Approach?
Stormwater refers to the flow of water resulting from the accumulation of precipitation. The quality and quantity of stormwater run-off in an urban catchment is determined by:
Types and levels of development
Maintenance of the drainage system
Management of pollution within the catchment
The need to preserve and improve water quality, amenity and biodiversity within an urban catchment is typically not considered in the planning of stormwater systems. This results in increased stormwater volumes and flows and the degradation of urban aquatic systems. These factors in turn pose a risk to public health.4
Effective management requires extensive infrastructure. In South Africa, the management of stormwater is typically separated from that of water and sanitation and rather assigned to the roads department. Stormwater is therefore approached as a hazard to be disposed of as quickly as possible in order to protect road structures , as opposed to being treated as a potential resource.
A holistic approach to infrastructure asset management, with a specific focus on water management solutions, integrates stormwater into the management of the urban water cycle and in relation to the broader municipal infrastructure asset management environment. Such an approach aims at making stormwater infrastructure more sustainable by integrating the planning and management of associated services with the rest of the urban water cycle including water supply, sanitation, solid waste and asset management.
In the South African context, this approach to planning, building, operating and assessing municipal infrastructure is particularly important when looking at stormwater in informal areas. For example, in a context where sanitation services are inadequate there is a risk that stormwater systems will be used for the disposal of black and grey water.
Human security is directly related to service delivery and the holistic management of the urban water cycle.
IMQS’s Stormwater Management Solution
IMQS offers a web based, spatially-enabled, Stormwater Management System application that contributes to its integrated Asset Management and Asset Registering suite of products. These products can either be used on a stand-alone basis or integrated in a broader IAM system that aims at delivering the right information to the right people at the right time.
The Stormwater Module is offered as a Water Solution along with its Water Demand Management and Water Services Development Planning Modules.
The module aims at enabling a Stormwater Management Service Department to:
Define the stormwater infrastructure asset inventory
Minimize disruptions and damage
Ensure residents are safe at all times
Utilise the benefits of rainfall run-off
Optimise the funding towards stormwater management
The module provides the following features that contribute to the effective management of run-off:
A stormwater infrastructure inventory defined for asset register purposes
Capacity of the stormwater network, run-off peaks and volumes
The effect of simulated high flows
The magnitude and locality of problem areas
The priorities of the different problem areas
The budget needed to solve the identified problem areas
The maintenance needs of the stormwater infrastructure
The proper maintenance and management of stormwater in relation to the broader urban water cycle is imperative in order to ensure the safety and security of municipal clients. A web based, spatially enabled software solution enables effective and informed decision making in real-time through establishing a visual and historical representation of the stormwater system. Information empowers the user to more accurately predict the future through the accumulation and analysis of past trends.