STORMWATER MANAGEMENT STRATEGY
Qianhui Sang (Lisa) 1357306
B 1:200
A
A
The stormwater strategy for the chosen site is to design and integrate stormwater management device between high density mix-use clusters and natural revegetation zone. The devices are ensure management of medium volume of stormwater and their contaminants that enter to natural stream from impervious surface such as roads and buildings.
B Rain Garden Species
Section AA 1:100
The rain garden basin is to be densely vegetated in order to maximize the contact between the water and plants stem. native plant species can tolerate both drought and flood condition. The overflow drain system is placed under boardwalk where is the deepest point within the basin. Sandy soil provides good drainage for the plant and four layers (pebble, soil, sand and gravel) will comprehensively filter the pollutants and sediment of rain runoff.
Constructed rain garden has been incorporated into high density impervious area in order to slow down and filter pollutants and sediment out of the rainwater runoff, absorb some of the runoff. This courtyard rain garden also provides the visual and natural amenity of the surrounding buildings. The devices are include the green roof and swale. The water runoff from green roof will be leaded to the rain garden or swale for secondary filtering by planting.
As the chosen site is quite flat, the rain garden need have larger inflow area for leading water to the garden. the rain garden inflow area is now total open for all direction runoff including water from swale and green roof. the raingarden maximun depth is 50cm, plant will not be planted to this level as this level is under the boardwalk and plant can not tolerate this water level. The landscape stone will also slow down the runoff and provide natural riparian landscape.
Although rain garden has both drought and flood period but in most time, rain garden is drought. The pebble is densely lay on the garden bed and stones provide a dry garden look for the rain garden for raising aesthetic values. Section BB
1:200