Water New Zealand Modelling Group - Auckland Regional Meeting

Water New Zealand’s Modelling SIG - Auckland Regional Meeting  

The Water NZ Modelling SIG invites interested parties to attend an informal get together.  Come along for a presentation preceded by light refreshments, followed by discussions whilst meeting other professionals with common interests.

Venue: AECOM, AECOM House, 8 Mahuhu Crescent, Auckland 
Date: Wednesday 15 April 2015
Time: 5:30pm 

RSVP by Friday 10 April
E: info@wse.co.nz                                                     
P: 021 326 979                                                                                                                                                  

“A Comparison of Four Types of Sewage Drop Structures through Physical Modelling.” - Tony Margevicius, AECOM


Dropping sewage from near surface collection systems into deep tunnels involves a number of challenges, including the odour control, air entrainment, solids management, energy dissipation, surge control, and access for personnel and equipment.  The use of drop structures to handle large flows will become more prevalent over the next several years due to the large number of Combined Sewer Overflow (CSO) tunnel projects on the horizon.  Numerous types of drop structures have been used to convey sewage to tunnels, with varying degrees of success.  Several recent projects have demonstrated that not all drop structures perform equally well.  While numerous models (both mathematical and physical) have been used to analyse drop structures, there is relatively little data that compares the performance of each type.  Much of the previous work has focused primarily on hydraulics, and comparatively little emphasis has been placed on the pneumatics of drop structures.  Both full-scale prototypes and laboratory-scale models suggest that the flow regimes in drop structures can be extremely complex and variable.  Further, the true nature of two-phase flow, which occurs in many drop structures, is not well understood or modelled in many instances.  Using both qualitative and quasi-quantitative criteria, this presentation compares the relative performance of four types of sewage drop structures:

•             The plunge drop,
•             The helicoidal ramp,
•             The vortex drop and
•             The cascade drop. 

In comparing the four types of drop structures, the presentation draws on several physical model results.


With over three decades of diverse experience in wastewater consulting, Tony Margevicius has been in responsible charge of various municipal water and wastewater treatment projects.  During his successful career, he has worked on hydraulic tunnels as large as 8.3 meters in diameter, on sewage pumping stations as large as 7,000 ML/d, and on three of the ten largest wastewater treatment plants in the world.  While his home town is Cleveland, Ohio (USA), he has worked on projects in the USA, Canada, China and New Zealand.  Always an innovator, Tony was one of the key drivers in bringing to New Zealand the first known cascade drop structure at the Rosedale WWTP.  Currently, he is serving as the Design Manager for the Central Interceptor project in Auckland.  He has a Master’s Degree in Civil Engineers with an emphasis in hydraulics and is a registered Professional Engineer in the State of Ohio (USA).  Tony is a Vice President in AECOM, and serves as the AECOM North American Wastewater Treatment Technical Practice Director.

Combining new technologies and Hydraulic Modelling: Towards Smart Water Supply Management” - Nasrine Tomasi, Mott MacDonald


In recent years technology trends have rapidly been moving towards cloud computing, big data analytics, mobility and social media. These ongoing trends have significantly impacted our personal lives. However the engineering industry needs to embrace these ongoing advancements to provide better services and ensure future proofing of the profession. More specifically in the Water sector, hydraulic modelling needs to adapt to stay at the forefront of technology in order to remain a crucial decision tool in smart water management. This presentation discusses how we believe these trends will affect the future of the water supply modelling practice and shows examples of alternative ways to deliver water modelling services.


Nasrine currently works for Mott MacDonald. She has seven years of experience in Water Resources Engineering. Nasrine has been involved in multiple water and stormwater modelling projects. Her skills also include valuable experience in the development of custom databases.



  • 15/04/2015
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  • 17:30 - 20:00
  • AECOM, AECOM House, 8 Mahuhu Crescent, Auckland , NZ