Research Journal of Science and Technology

Rahul R. Biswas ¹, Tripti R. Biswas ²

Affiliations
1 Christchurch City Council, Christchurch, NZ
2 Christchurch, NZ

Abstract

Earthquakes can cause a variety of damage in a wastewater network. One of the key impacts of an earthquake is the increase in wastewater overflow due to high inflow and infiltration. Earthquake impacts on sewer overflow volume and sewer overflow water pollutants in Christchurch are reported in this paper. Two hydraulic models (the 2010 pre-earthquake model and the 2011 post-earthquake model) were used as part of this investigation. In Christchurch, earthquakes caused a 30% increase in wastewater overflow volume in a 1 in 3 year’s rainfall event whereas the sewage overflow volume had increased by around 18% and 15% during the 1 in 5 years and 1 in 10 year’s rainfall events respectively. The amount of water pollutants discharged via sewer overflow increased by around 40%, 12% and 8% in the 1 in 3 year’s, 1 in 5 years and 1 in 10 year’s rainfall events respectively. Though there was a significant increase in sewer overflow volume in the post-earthquake network, it did not mean water pollutants discharged via the sewer overflow points also increased significantly. The concentration of water pollutants decreased as the sewer overflow volume increased.

Keywords

Earthquake Effects, Hydraulic Model, Water Quality, Wastewater Network, Wastewater Overflow Pollutants, Wastewater Pollutants.

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