Our Changing World for Thursday 20 February 2014
Looking After the Ashley-Rakahuri River
The Ashley River is a typical braided river with wide shallow braiding river channels - it is fed from the foothills rather than the Main Divide, so has fewer floods than some of the larger braided rivers. Nick Ledgard (right) uses a spotting scope to study the rare shorebirds that breed on the Ashley River (images: A. Ballance)
Braided rivers are a distinctive feature of New Zealand, and particularly Canterbury. They form as rainfall from the Southern Alps and its foothills meanders its way across the wide gravel Canterbury Plains. Braided rivers are one of the last native habitats left on the highly modified plains, but they face a range of threats and uses, from gravel extraction and recreational four-wheel driving to introduced predators.
The Ashley-Rakahuri Rivercare group was formed in 1999 to help look after the lower reaches of the Ashley River in North Canterbury. The main aims of the group are to protect birds and their habitat in the riverbed, to monitor breeding success, and to promote these activities to the wider public. The core study area consists of an 18km stretch of riverbed just north of Rangiora, extending from the confluence of the Okuku River down to the State Highway 1 road bridge.
Alison Ballance joins Nick Ledgard to hear about some of the rare shorebirds that breed in the river, and make a quick visit to a wrybill nest.
A colony of black-fronted terns and black-billed gulls early on in the breeding season, and (right) two wrybill eggs on a 'nest' of small pebbles (images: A. Ballance)
Environment Canterbury Water Commissioners
View of the estuary at the mouth of the Waimakariri River, one of Canterbury's large braided rivers (images: A. Ballance)
Donald Couch is one of seven Environment Canterbury commissioners appointed in 2010 to replace the previous elected councillors. Among the mandates of the regional council is the management of water in Canterbury. Donald’s area of responsibility include biodiversity, natural hazards and flood protection, and Alison meets him at the mouth of the Waimakariri River as takes a break from a briefing field trip to talk about some of the issues around conserving freshwater biodiversity in Canterbury.
Donald also featured in the recent Treaty Debate 2014 which discussed water rights in Aotearoa - New Zealand.
Science of Fireworks
Large public celebrations, rock concerts, and sporting events, like the Winter Olympics, all use massive fireworks displays to wow the crowd. Behind the scenes, pyrotechnic experts need to have a keen understanding of physics, chemistry and even psychology to ensure fireworks explode safely with the right colour, sound and timing. Anthony Lealand (right) from Firework Professionals takes Ruth Beran on a tour of his pyrotechnic facility in Christchurch, and explains the science behind fireworks, how they are manufactured, and demonstrates some of the different sounds they make.