Chaohu Lake RTR24QAT 1024x681

30 January 2019 Chloe Brigden

As water temperatures rise so does the potential for algae blooms, unsightly at the least and, at worst, toxic to other organisms including freshwater, marine mammals, birds and humans. 

What’s more, the effects of climate change may increase the severity and frequency of these events.

Algae play a vital role in a healthy ecosystem but, as with anything, too much of a good thing can overbalance the natural order and an algae bloom 

Hot, wet atmosphere helps algae bloom to enlarge and explode. The bacteria from these blooms is most concerning as they can release all sorts of deadly poisons into the environment. Their density and mass can cover entire lakes, blocking light and oxygen; disrupting everything from aquatic ecosystems to drinking water systems.

This releases a number of harmful cyanotoxins into the atmosphere and it’s these events that we should worry about. Cyanotoxins pose a threat to all living things above and below water. Above water symptoms include, nausea, vomiting, and in overseas reports there have been cases of liver failure and death. 

Last year, Hawkes Bay Regional Council released a community caution. This year health warnings were issued for Rotorua’s Lake Okaro and Lake Rotehu before summer began.

Although we need a more concentrated approach to New Zealand’s freshwater status, there is a quicker, cost-efficient and collaborative alternative that’s closer to home. 

In a nationwide poll conducted by Colmar Brunton last year, 82% of New Zealanders voiced extreme concern for the condition of their local lakes, rivers and streams.

We know that communities are apprehensive about walking their pets, swimming and in cases, simply passing by their local streams. We also know that there is enthusiasm for a long-term, fit for all solution.

What if we could empower our communities to take action? To ultimately govern the health of their surrounding wetland areas?

By engaging with the local communities who are ardent to see change, we can design a nationwide approach that will ultimately provide bespoke results at grassroot level. We have the opportunity to provide communities with tools, resources and responsibility, to take ownership of their catchment waterbodies.

By involving local communities, we will also gain a rich dataset into the challenges that our lakes and waterbodies are facing. Enabling an 80/20 pareto approach to targeting efforts into the worst areas.

Some of New Zealand’s catchment areas have experienced first-hand the success of community-engaged initiatives and future.

Is it possible...?

With urban settlements forecasted to account for over 80 percent of the world’s population by 2050 (UN,2010), cities represent our greatest opportunity to reverse the significant environmental degradation of our past.

But rapid urban growth can be both an opportunity and a threat...

A future-ready vision for Christchurch City Council

In 2016, Christchurch City Council reached out to WSP Opus to develop a future-ready vision for one of its urban catchment areas.

Throughout Christchurch, the natural water system has been impacted by urban development. This means the general ecosystem health of the creek - and ongoing flooding issues -  had created a degraded environment.

The area was also heavily trafficked and there was limited recreational space. Ultimately this affected the community’s attitude and behaviour towards the site, with the community turning their backs on the creek and, in some cases, each other.

Christchurch City Council gave WSP Opus full licence to scour international practices to identify and develop a future-ready framework for New Zealand’s urban environments.

We addressed and determined principles based on several fundamental human-centred well-beings.  These guided our concept of human-sustainable urbanism.  We presented the council with a range of small and large initiatives with the power to transform the catchment by reconnecting residents to the creek. These included:

  • Increasing the open space areas on the site by over 400% to provide recreational opportunities for the community, along with integrating a healthy, accessible waterway system throughout.
  • Introducing a blue-green water boulevard connecting to the wider city. The boulevard performs as a floodplain in significant events. The buildings and transport modes within the boulevard are isolated from the floodplain.
  • Further street scene typologies that incorporate.
  • Bioretention swales to capture, treat and infiltrate stormwater runoff as it moves downstream, wide pedestrian footpaths and smart LED street lights for community safety, plus native and exotic planting for greater biodiversity, improved community aesthetic and amenity plus air purification and cooling.
  • ‘Pollinator’ paths to generate a wide range of ecosystem services that spread across social, cultural, environmental and economic welfares.
  • District-wide electric light rail corridor to strengthen crime prevention through environmental design (CPTED) and to encourage the community to engage with. 

    The next phase of this work would be to deliver a collaborative framework across the communities and the many varied stakeholders from the City Authority to other private and public organisations.

    Working alongside Christchurch City Council, we aim to deliver a net positive urban catchment approach across the whole city.