When the Selwyn was deep and broad

Much is talked about the Selwyn River, so I would like to add a piece of long-forgotten knowledge about its wanderings, if I may.

Readers may well remember the Russley Hotel that was on Roydvale Ave in Christchurch. When it was built, excavations took place with the idea of an underground car park. Some 40 years ago, the Selwyn Ford out on the plains had a reputation of being both deep and broad and when in flood, it drowned cars and traction engines.

An odd thing always happened five days after the Selwyn Ford was in flood: Water would flow kneedeep under the hotel quite briskly westwards towards Wairakei Rd whence it disappeared into the gravel bank at the end of the building. At the same time on the other side of Roydvale Ave there were gravel pits and Lake Bryndwr’s water level would obediently rise by 1.75 metres. A few days after the Selwyn Ford had thrown its tantrum, the waters would subside.

This all rather bears out the suggestion that the river had a leak and much of its flow was going on under the gravel riverbed to goodness knows where. Derek Upton St Albans

‘Restored flow’ is meagre

Chris Rennie’s letter on the Selwyn (May 5) is misleading. To clarify, firstly, only the river’s middle reaches are ‘‘perennially dry’’, and a ‘‘river of gravel’’. The upper and lower reaches are normally rivers of water. Secondly, the effect of headwaters’ rainfall on the lower river is uncertain. Allegedly water from the upper river goes underground and reappears in the lower river, but the extent of this is anyone’s guess, especially with the advent of seasonal irrigation.

Rennie does not mention that the lower Selwyn and its neighbouring streams – the LII, the Irwell and Harts Creek – have always relied on local groundwater to maintain flow levels. Or that seasonal irrigation now competes for this water too. Finally, what Chris calls the ‘‘restored flow’’ of the Selwyn is so meagre that it peters out near the upper huts. Dirty, polluted lake water now ‘‘flows’’ back up the river for about 3 kilometres. Bill Horsley Rangiora

The Russley Hotel in northwest Christchurch that later made way for a retirement complex.