In a series of demonstration projects of climate adaptation and green rainwater solutions in Brøndby, HOFOR, in collaboration with Brøndby Municipality, in 2015 carried out a the transformation of an existing parking lot into a climate parking Lot, at Tjørnehøjskolen in Brøndbyvester. The school’s parking lot now serves as a delay basin for rainwater in case of heavy rainfall.
Elements: Above ground – parkinglot with raised curbs and speed bumps at exits; Below ground – collection well with water brake; Backup – football field as overflow area
Dimension: 6000 m2 of rooftop area (school buildings), 340 m3 retention volume in the parking lot
Project partners: HOFOR – Greater Copenhagen Utility, Brøndby Municipality, Brøndbyvester School, Dines Jørgensen & Co engineering and Aarsleff.
Some minor adjustsments have been made on the surface: The existing curb around the parking lot now forms a basin. It was elevated at some points to achieve an equal height. At the entrance and exit, bumps have been established, which slow down traffic and can keep the rainwater inside the parking lot.
The rainwater in the underground pipes is led to a well, where a water break regulates the discharge. Under large loads, the break reduces the amount it discharges into the connected combined sewer system. When this happens, rainwater slowly fills the parking lot, coming from below. The parking lot becomes a temporary delay basin. From here, the water will slowly discharge into the sewer. If there is too much rainwater coming into the system, excess water will flow out over the bump towards the adjacent football pitch.
In connection with the establishment of the climate parking lot, som parts of the system were renewed or adapted. Nearby rain gutters were connected to the rain water well, at the heart of the system. Traffic safety was also improved, as a new cycle path along the parking lot was established, to provide easier access to the school and to separate “soft” traffic (bikes & pedestrians) from “hard” traffic (cars).
The project is the result of a collaboration between HOFOR – Greater Copenhagen Utility, Brøndby Municipality, Brøndbyvester School and Dines Jørgensensn Engineers and Aarsleff.