Transcript of Blue-green networks explained video
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[Animated video: View of houses on a hill and over the sea in the background we can see the Sky Tower. It is raining.]
Voice: When it rains, water travels from the top of a stormwater catchment down to the sea.
[Video: Images that show water on the surface of the ground, under bridges and running between houses.]
Voice: On its journey water travels over the ground as overland flow, through pipes and road culverts, and along channels and streams.
[Video: View of the houses on the hill with rain creating flooding reaching some houses.]
Voice: In very heavy rain or intense downpours, the amount of stormwater can exceed our pipes and streams’ capacity and flood our communities.
[Video scene 1: View of flooded farmland and buildings surrounded by water, with animals in the foreground and in the distance on a hill above the water. It is still raining heavily.]
[Video scene 2: View of a street with houses. Water moves down the street toward a stormwater drain and beginning to flood the street and the nearby houses. The rain eventually stops and the sun comes out.]
Voice: Due to climate change increasing the frequency and size of storm events, many houses in low-lying areas and flood plains are now at increased risk of flooding. While more or larger pipes may resolve some issues, it's not always possible or cost effective to do so. We need to make more space for water to flow safely through our neighbourhoods without causing risk to people and property.
[Video: View of parkland with houses nearby and a large stream flowing past the houses but not reaching them. The rain stops and as the sun comes out the stream gets smaller.]
Voice: Creating blue-green networks is one way we can do this. A blue-green network is the creation of open parkland within the floodplain of a stream to better carry rainwater during a storm, diverting it away from neighbouring buildings. During dry weather, the park functions as normal for the community to enjoy.
[Video: View of a desk with blueprints of houses on them with a stream flowing between them. A person circles some of the houses using a white pen.]
Voice: To create a blue-green network, some buildings may need to be removed to create the park and widen the stream. Usually, these are houses with a high flood risk, but not all houses that flood need to be removed, and some houses that don’t currently flood may need to be removed for the blue-green network to function properly. Deciding which properties to remove involves looking at the area as a whole.
[Video scene 1: View of houses with a stream running through during a rainstorm. As the rain falls flooding occurs between the houses and the houses touched by the flooding turn red.]
[Video scene 2: The view pans to houses further up the hill beyond a culvert. There are larger floods here touching many houses which turn red. An arrow points toward the culvert which is only letting a small amount of water out.]
[Video scene 3: The view pans once again to the houses with the stream which are now flooded even more. More houses turn red as the flood water reaches them and rises.]
[Video scene 4: All the red houses disappear momentarily. then some of the houses reappear and the path of the stream is changed taking up some of the room made by removing some of the houses. Trees and people appear next to the stream, the culvert is enlarged and the houses beyond the culvert now no longer have any flooding. The rain has stopped.]
[Video scene 5: We see the entire view of the houses with all the changes made. The rain has stopped and people are enjoying the newly created parkland.]
Voice: In this example, all of the properties will flood in an extreme storm that has a one per cent chance of occurring every year – known as a 100-year event. These properties are in a low-lying flood plain close to the stream, which floods when the stream overtops. These properties flood because the culvert downstream is too small and creates a blockage in heavy rain. While increasing the size of the culvert would reduce the flood risk to the properties upstream, it also increases the risk to the downstream properties, so by itself won’t solve the problem. Removing all the properties from a flood plain and surrounding area is costly and disruptive. Instead, by removing a small number of properties and deepening and widening the stream, we could create a blue-green network. This reduces risk for the whole community, particularly the remaining neighbouring homes. The increased water capacity downstream allows the culvert to be expanded safely, helping the upstream houses as well. The planted stream will improve water quality and add ecological value, while the park will be a place for people to use and enjoy.
[Video: A satellite map view of Auckland is shown with blue dots in the north, south, east and west. Photographs of Mt Roskill, Takaanini and Browns Bay appear next to the blue dots in the correct locations on the map.]
Voice: Blue-green networks already exist in Tāmaki Makaurau, including Te Auaunga in Mount Roskill, Awakeri Wetlands in Takaanini and Taiaotea Creek in Browns Bay.
[Video: View of terraced houses and villas next to a stream while the rain pours.]
Voice: To create the space needed for a blue-green network, some houses in high flood risk areas have to be removed.
[Video: A blue banner appears with the title '2023-2024' and the text 'property categorisation process and buy-outs take place' and 'blue-green locations investigated' (all in upper case). Under this box another box appears with the title 'July 2024-2034' with the text 'making space for water begins' and 'construction of blue-green projects likely from 2026 onwards' (all in upper case).]
Voice: The majority of these will be identified through the property categorisation and buy-out process which has been set up by Auckland Council and the government in response to the severe weather events of early 2023. Making Space for Water is Auckland Council's 10-year flood resilience programme and includes seven initiatives, one of which is creating blue-green networks.
[Video: Satellite view of Auckland with blue dots highlighting the following locations; Kumeū River, Waimoko Stream, Opanuku Stream, Porters Stream, Whau Stream, Te Arata Creek, Harania Creek, Te Auaunga Stream, Sandringham/Epsom/Mt Eden, Opoututeka/Coxs Creek, Wairau Creek, Whangapouri Creek.]
Voice: Twelve areas have been initially identified, though some may not go ahead and new projects may be introduced. Once clusters of houses have been categorised and agreed for removal, the extent of the project can be fully scoped and delivered. Construction of the first blue-green networks is likely to begin from 2026, with most being completed within the 10-year programme period.
[Video: The Auckland Council logo appears with the website address 'www.aucklandcouncil.govt.nz/bluegreen'.]
Voice: Visit the Auckland Council website to find out more.
[Video ends.]
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