THE RICCARTON BUSH

Press, Volume LXXXII, Issue 24910, 25 June 1946, Page 3

THE RICCARTON BUSH

DRAINAGE THREATENS DESTRUCTION

SURVEY BY MR C. R. RUSSELL

Subdivision and drainage of the , hOma . ste . ad estate would almost certainly destroy Riccarton Bush, which is .the last remaining part of the ■? cl^n^, C S nterbury swamp forest, said . r u C ' R - Rus seU, secretary of the Canterbury branch of the Royal Society of New Zealand, yesterday. Mr Russell who is a civil engineer, carried out a survey of the area during the weekend.

,v L . e Y, els „ taken by Mr Russell showed that the floor of the bush was four feet above the surface of the Avon river but the ground water in the bush was within a foot of the top of the soil. The ground water level probably remained almost constant throughout the year. The ground sloped gently in a direction a little north of east from the bush through the Deans homestead estate, said Mr Russell, but the flow of the ground water in that direction was so delayed by a clay pan that it was imperceptible. In such soil, the flow could not be more than one foot a day, and was probably nearer half that. Water accumulated in the bush during the winter was retained there throughout the summer.

Mr Russell said that any ordinarily efficient system of drainage in the Deans homestead area would alter the position. As there was a long boundary between the homestead estate and the bush, drainage would lower the level of the ground water throughout the bush by three feet, so that instead of there being water at a foot below the surface Of the ground, the water wouldbe four feet below ground level. No swamp forest tree could survive such a change in the water level, said Mr W. B. Brockie, who is in charge of the native plants at the Christchurch Botanic 'Gardens, when Mr Russell’s report was referred to him. Such trees were not deep rooted, he said, and the draining away of three feet of water from their roots would prove fatal. The report was very drastic, he added, and he could not imagine the kahikiteas surviving such a sudden change after living in a special environment since the sixteenth century.