The Basin Reserve flyover could put a new spin on bowling conditions at the historic cricket ground, experts say.
Inside knowledge of how to bowl in Wellington's breeze has long given the Black Caps home advantage, and could well do so again today when they begin their test match against the West Indies.
But a 12-metre-high pavilion to be built at the northern end of the ground, if the proposed flyover goes ahead, could change all that, according to a report by aerodynamics expert Neil Jamieson and building design expert Michael Donn.
The pavilion would mean more shelter at the top end in a stiff northerly, and could also create a wind-tunnel effect around the spectator entrance, they say.
Both recommend improving the entrance design because of the likelihood that wind speeds will be higher than through the existing gate.
Former New Zealand paceman Ewen Chatfield, who famously toiled into the wind at the Basin for most of his career, said knowing how to bowl in Wellington conditions was a huge advantage.
"Some of these touring countries don't have wind the same strength as what we get in Wellington, so most of them struggle to bowl into it," he said.
"Sometimes you'll see them bring on the slower bowlers or the spinners because of the wind strength, not because of the wicket." A constant northerly was actually easier to bowl into than a stop-start wind going in different directions.
Retired scientist Brian Wilkins, who has researched the aerodynamics of cricket balls since 1988, said smooth air was best for swing and the new Basin pavilion would probably disrupt that. He doubted the change would be significant though, as there were already plenty of stands and gates at the northern end of the ground interrupting wind flow.
"The best conditions for swing at the Basin is actually when the southerly is whistling up from Island Bay."
In February, an independent board of inquiry will consider the New Zealand Transport Agency's application to build a $90 million flyover, 20 metres north of the cricket ground.
The board asked Jamieson, acting for the Transport Agency, and Donn, for the Architectural Centre and Newtown Residents Association, to get together and decide what they could and could not agree on ahead of the hearing.
Other experts in the fields of traffic engineering, archaeology and ecology were asked to do the same.
Jamieson said the wind tunnel effect of the new entrance would not be a problem if the gates were closed or screened, as was the plan on match days.
Chatfield said he would not be upset to see the flyover built, provided it was obscured by plenty of trees. "I'm a taxi driver now so I'd rather drive on the flyover than get caught up in traffic at the Basin Reserve."