Halswell and Water

Halswell is an interesting spot in terms of drainage.  

Water drains west down to Te Waihora Lake Ellesmere from some parts of the area while, from other parts of Halswell, it drains east down into the Ōpawaho Heathcote River.  Aidanfield and the areas around the Domain drain east, while Westlake, Oaklands, Country Palms, Knights Stream and Longhurst all drain west via the Huritini Halswell River.  Rain that falls around the area therefore can contribute to flooding in both directions in heavy rain.

Built environments, like the City of Christchurch, have a lot of hard, impermeable surfaces that don't allow rain to soak into the ground.  This includes roof areas, and asphalt or concrete.  The Ōpawaho Heathcote in particular has been increasingly subject to flooding from rain events as the area of impermeable surfaces has grown.  This is because it drains a lot of low lying land in the City and because our climate has changed over recent years.  We are having more droughts and fewer but bigger rain events rather than many small ones.  

The City Council is addressing this in a number of ways.  One is that for infill housing in some parts of the City, developers must put in tanks that collect water in a flood event and release it slowly after the event.  You too could assist that process by putting in rainwater tanks which can be used to water gardens, or, if you are really keen, might be plumbed into your toilet to help cut down your water use in the summer months but which fill during rain events and hold some water back.  

Another way that flooding is being managed in both directions is through the development of water retention areas.   In this, Halswell is very important, as we can see from water retention ponds and areas that fill with water when it rains.  You can see these in the Wigram Basin, around Aidanfield, in Ngā Puna Wai in the Halswell Domain and in Henderson's Basin - along either side of Sparks road and Cashmere Road.     

Water retention areas are also visible around Quaifes Road and Saby's Road, along the bottom of the Hill to the Quarry where a lot of water is held back from the Huritini Halswell River.  More will be built as development in this area continues.  Selwyn District Council is going similar work around Lincoln, Prebbleton and Tai Tapu as those areas develop.

The bonus for us here in Halswell is that we have a lot of very nice green spaces that have been and will be planted out in natives and which are great places for walking and biking.