Water New Zealands 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:OPUS International Consultants Limited, The Westhaven, 100 Beaumont Street, Auckland
The presentation focuses on providing an overview of our recent research on (PDS) and its applications to the North Island of New Zealand in the analysis of extreme rainfall. The presentation will provide an overview of the key issues needed to be considered when applying PDS. The presentation will also discuss the statistical properties of PDS and its use in the regional frequency analysis of extreme rainfall in the North Island.
Twenty-four years of 5-minute rainfall data from across the Auckland Region has been analysed and quality controlled. The purpose: to develop a series of long-term continuous rainfall timeseries spanning the Auckland Region from Wellsford to Pukekohe. Watercare will use the continuous rainfall timeseries to assess wastewater catchment hydraulic and hydrologic performance.
Previous work by Watercare has confirmed the importance of antecedent conditions when assessing network performance. When soil moisture is low, a relatively large rainfall event may produce little response from a catchment. When soil moisture is high, the same storm could create a large response. In slow responding catchments, previous work has found that it is often a small storm that breaks the camels back if it occurs after months of above-average rainfall. A long-term continuous rainfall timeseries enables the effect of antecedent conditions to be factored into the statistical outputs from a network system performance study.
We discuss factors affecting the long-term weather patterns in Auckland. We discuss which periods in the past 24 years were wet, those that were dry, and those that were average. Over 250 years of continuous 5-minute rainfall was quality controlled for this project. We discuss how this large quantum of rainfall data was reviewed without consuming endless hours of staff time. We reflect on observations noted during the project: how good is the data quality-coding supplied with the rainfall data? which rain gauges in the region had the most consistent records? How much historic 5-minute rainfall data is available? Finally, we will expand upon some of the intended uses for the long term rainfall timeseries that were developed.
RSVP by Friday 7 November
P: 021 326 979
*Please forward to anyone you know who may be interested all welcome