There are five core steps to stormwater capture: End Use, Collection, Treatment, Storage, and Distribution.
End use Water resources become more scarce as the human population grows. Populations need to create systems and methods to minimize water consumption at all levels, while simultaneously engineering new methods of
water reuse. For non-potable water purposes with lower water quality needs, people can use stormwater for toilet flushing, gardening,
fire fighting,
irrigation, etc. For potable water use of higher water quality, stormwater needs to be highly treated before final use. The latter has rarely been used around the world. in streams, lakes, and nearshore coastal environments, as well as promoting groundwater recharge. The intended end use of a system will determine the level of treatment and processing of collected stormwater.
Collection for stormwater collection Stormwater collection is a process of directing water into storage from stormwater gathering, such as
urban runoff. Generally, there are two types; online storages and offline storages. Online storages are a conventional way of acquiring stormwater directly from waterways or drains. For instance, the urban drainage system of channels and pipes conduct stormwater into storage facilities, For instance, weirs divert flows into stormwater containment and contribute to a large part of stormwater catchment for a city, where it is then stored for future treatment and distribution. Stormwater collection is widely practiced for purposes of urban runoff and flood mitigation as well.
Treatment Stormwater treatment is the greatest challenge for stormwater harvesting. Water treatment processes depend on the intended end use and the catchment equipment, which determines the level of pollutants to be filtered and removed. For instance, construction uses may only require non-potable water where the water processing includes only
filtration and
disinfection. However, for potable uses of higher water quality, the treatment process requires screening, coagulation,
filtration, carbon adsorption, and
disinfection.
Storage There are three factors to consider in terms of storage: function, location, and capacity. The planner is responsible for determining the end use of the stored stormwater, such as fire fighting, industrial water supply, farming and irrigation, recreation,
flood mitigation, groundwater recharge, etc. Regarding location of a system and its storage, a water tank in proximity to the waters' end use may be the best design. If the collection system is intended to slow runoff and/or recharge an aquifer, an on-site, below ground infiltration systems may be considered. Choices between online and offline storages can affect the surrounding natural aquatic systems and yields different maintenance costs and
flood mitigation effectiveness. The capacity of a storage system will be determined by the type of end use in a particular climate or period of time.
Distribution Generally, there are two types of stormwater distribution systems. The first is open space irrigation systems. This application uses treated stormwater to irrigate open spaces such as parks, municipal green spaces, golf courses, etc., and can be implemented at a hyper-local scale (ie catchment and reuse occurs at the same park). Another system is a non-potable distribution system which distributes treated stormwater to be used for things like toilet flushing, fire fighting, and some industrial uses. This system may require additional infrastructure such as a third-pipe network for distribution. == Concerns ==