Storm water system damage
Our storm water system suffered similar kinds of damage to our wastewater system:
- Kerb and channel breakages
- The earthquakes cracked, deformed, and disintegrated some roadside guttering. These are usually fixed as part of road repairs. Even damaged roads affected the storm water systems because they could not divert storm water into the storm water drains.
- Roadside drain damage
- Storm water drains broke up or collapsed, leaving them unable to take in and channel the required volume of water.
- Brick drain damage
- Some quite large sections of Victorian-style brick drains still in use in central Christchurch and in Lyttelton collapsed.
- Liquefaction blockage
- Liquefaction left deposits in some storm water systems after it dried up, causing blockage.
- The earthquakes cracked pipe walls, allowing all kinds of other liquids and obstructions into the pipes. The liquids include groundwater and liquefaction silt. These are a problem mainly because they reduce the carrying capacity of wastewater systems.
- A few storm water pipe sections completely collapsed, particularly older earthenware pipes. Storm water pipes suffered more collapse than fresh water pipes because they had a higher proportion of old materials.
- Joint breakage
- A common form of damage is when pipe joints separate due to ground movements like lateral spreading. These pipes are essentially broken.
- Pump station damage
- Pumping stations suffered a relatively small amount of damage. This was usually separation of inlet or outlet pipes at the pump station wall.
- Loss of gradient
- Pipes generally run water in a downward gradient to take advantage of gravity. Liquefaction pushed some pipes up, which reduced the gradient over a widespread area.