Water harvesting is the practice of capturing, storing, and using stormwater on-site, as opposed to traditional stormwater management techniques that channel stormwater into curbs and culverts. Water harvesting systems are commonly referred to as "green infrastructure" and usually include two essential elements: curb cuts and bioswales.
Curb cuts are strategically placed breaks in the curb that allow water to leave the street, sidewalk, or trail. Curb cuts require a specialized saw to begin the process. After the initial cuts, a hammer and chisel are used to remove remaining curb segments. Lastly, the curb cut is polished to a smooth finish, with a slight slope away from the street, sidewalk, or trail. Best design practices recommend adding a rock-lined catch basin that serves to reduce flow velocities as well as capture any debris or litter, simplifying maintenance of the swale.
Existing bioswale near Hidden Valley Park prior to water harvesting feature installation
Bioswales are shallow depressions or basins meant to capture and retain stormwater. These features can be a variety of different shapes and sizes based on capacity requirements and site limitations. Bioswales are often incorporated into the parkway, along roads with ponding issues, near ditches, in parks, roadside medians, roundabouts, and other public spaces. It is important to pay attention to the flow of stormwater across a site to identify areas of flooding and floodwater damage. Wherever these issues occur, bioswales can be used to slow, spread, and sink stormwater.
Bioswales often incorporate native and desert adapted plants and landscaping elements, using the captured stormwater for irrigation purposes in order to maximize the benefits of the water harvesting system. It is important to place plants at appropriate locations within the bioswale and along the berm to ensure plants receive the proper amount of water; plants located higher along the berm receive less water than plants located towards the bottom of the bioswale.
The first step:
Dig a hole!
Determine the bioswale shape and depth based on design capacity
Properly designed bioswales require minimal maintenance. Best practices recommend that water harvesting systems include a rock-lined catch basin beneath curb cuts in order to capture debris and litter in one consolidated location, rather than having to pick up trash throughout the length of the bioswale.
It is common for organic material, such as mulch, to be washed away or displaced following the first heavy rainfall after installation. This can be remedied by using a broom to sweep the organic material back into the bioswale and then compact the organic material using a steel tamper.
Appropriately selected plants and trees may be able to survive off of the rainfall captured by the system upon reaching maturity, though plants will require watering during establishment and times of intense heat and drought.