19, 13 and 20 WWPSs in Blenheim, Gisborne and Hutt City were selected respectively to show how vulnerable WWPSs are.
About 60% of Hutt City and Blenheim's wastewater pumping stations were built or refurbished before 1976, followed by 40% of Gisborne's WWPSs.
WWPS buildings, not including some trunk WWPSs in Hutt City and main WWPSs in two other cities, have small area sizes while building area in common WWPSs vary between 6 to 25 square meters.
Regarding the greatest numbers of WWPSs with buildings in the Hutt City wastewater system compared with Gisborne and Blenheim, initial earthquake assessment procedure recommended by NZSEE (2006) was applied to disclose the Hutt City WWPSs' building vulnerability to earthquakes.
Geological characteristics of each WWPS in Hutt City including soil types were extracted from the available sources (Dellow, 1992; Van Dissen et al.
WWPSs structure assessment by the author revealed that 57% of the Hutt City WWPSs which were built before 1957 are significantly vulnerable to earthquake and should be retrofitted according to the 2004 building act.
All participants who provide information and recommendation are gratefully acknowledged including Hutt City Council, Capacity Company, GNS and MWH.
Hutt City Capacity Company and Hutt City Council: 137.
The Wellington WWTP was built in 1998 while the Hutt City WWTP was commissioned in 2001 (Capacity-Co.