Design of Co-catchment Facility
Co-catchment is an innovative approach to better manage the environmental and economic impacts of urban runoff. It is a concept that combines stormwater management, flood control, water harvesting, and reuse of urban runoff for beneficial re-use. The primary objective of co-catchment is to reduce runoff volumes, reduce non-point source pollution, improve water quality, and provide opportunities for multiple water-use benefits. Co-catchment facilitates water reuse by efficiently intercepting and collecting roof runoff, reducing impervious area and evapotranspiration losses, and reducing energy usage associated with wastewater treatment.
Co-catchment has been adopted as a major component of stormwater management in many cities and towns around the world. The design of a co-catchment facility should meet the specific needs of the community it serves. This includes identifying potential locations, sizing of the facility, defining its design objectives, including additional functions to be achieved, and determining the appropriate combination of measures to meet the need of the site. The design of a co-catchment facility should consider the following elements in the context of their specific site conditions:
Location: The location of the facility should be chosen to maximize the positive impacts of the facility and to minimize any negative impacts. There should be adequate space to accommodate the service envelop of the facility as well as room for the installation of associated equipment. The location should also provide easy access to the necessary services and utilities required to operate the facility.
Size: The size of the facility should depend on the anticipated demand and the needed performance. The facility should be designed to meet the peak flow requirements and to accommodate the associated frequency of use. In some cases, peak flow detention basins may be required to reduce the frequency of high flows.
Design Objectives: The design of a co-catchment facility should specify the associated objectives of the facility; such as stormwater management, flood control, water harvesting, and reuse of urban runoff. The objectives should also include additional functions that may be required to meet the needs of the site; such as habitat restoration, ground water recharge, and infrastructure protection.
Precipitation Interceptors: Design features should include appropriate measures to intercept and capture roof runoff. This includes the use of canopies, cisterns, underground storm chambers, rain gardens, swales and other measures to store and convey the runoff.
Hydraulic Control: Hydraulic control measures should be included in the design to reduce peak runoff and improve water quality. This includes detention basins, retention basins, subsurface channels, and other measures to reduce runoff and slow the discharge of runoff.
Utility Connections: Utility connections should be included in the design of a co-catchment facility to allow for the collection, storage, treatment and distribution of the captured runoff. This could include the use of pump stations, treatment systems, valves, and associated piping connections.
Maintenance Plan: The maintenance of a co-catchment facility should be determined based on the objectives and anticipated use of the facility. The maintenance plan should include a schedule for routine inspections, maintenance, and repair of the facility and its associated features, as well as any necessary equipment or systems.
Co-catchment facility design is an important tool in the reduction of urban runoff. It enables communities to better manage their water resources, improve water quality and reduce the potential impacts of flooding. The design of a co-catchment facility should consider the needs of the site, the objectives of the facility, the associated design elements and the necessary maintenance plan.
