HB warning in Aberfan tragedy.
Mr Editor: The “Warning for Hawke’s Bay?” question raised in your last Saturday’s issue by the Rev. Quentin Nelson, MA, in relating the Welsh slag-heap tragedy at Aberfan to the potential flood disaster in Hawke’s Bay from its rivers is a fully justifiable parallel.
[…] implementing the scheme [ ] being carried out the Hawke’s Bay Catchment Board is following not the […] choice even of its own engineer, but a far less effective procedure that does appear more easily identified with local politics than with long-term security. Its engineer has publicly stated that it will need adjustments within 20 to 25 years.
Other eminent engineers have supported the late Mr George Nelson’s contention that only more comprehensive realignment than is being carried out would provide the margin of safety for the future and avoid the previous recurring pattern of the board having to bring forward new schemes soon after the preceding ones had been completed.
The Rev. Quentin Nelson mentions that it was the sight and stench of the bodies of beasts hanging in the trees, plus the many people whom he knew who had been swept out to sea and drowned in the great flood of 1897, which evoked a vow from his father, then a young man, to become responsible for seeing that such a disaster never happened again.
Thenceforth George Nelson devoted himself to special study of the problem and later accepted and created every possible opportunity for representation to those in authority at the highest Government and local body levels as well as by special articles and through the correspondence columns of the Hawke’s Bay Herald and Herald-Tribune.
Most of our adult community knows that Mr Nelson maintained this effort until his final days. Few of the public, however, are aware of the tremendous and unremitting effort which provided the background for the principles of river control and ultimate practical plan which Mr George Nelson so staunchly advocated.
From the time of the 1897 flood Mr Nelson investigated in the most meticulous detail every possible source of information relating to the past history of the Hawke’s Bay rivers from the writings and personal records of the early settlers and missionaries, Maori personal experience and father-to-son accounts – of rainfall, previous floods, and changes in the course of the rivers plus silting-up of the riverbeds. Between 1892 and 1928 the riverbed at Pakowhai was raised 15ft above the former level and this siltation continued in the lower reaches. Surveys were made of the riverbeds and surrounding land to obtain their grade of fall; cross sections were taken to gauge the nature of the country and degree of past silting.
History revealed that while “flash floods” could occur anytime – as in the near calamity of 1963 which swelled to “within two or three inches” of topping the floodbanks and deluging Napier and environs – floods of major proportions occurred every 30 to 40 years and those of devastating magnitude about once every 100 years.
Not satisfied with every available local fact and his personal knowledge of the rivers since boyhood (his father was chairman of the Clive Rivers board), Mr Nelson proceeded overseas to study the principal shingle rivers of Switzerland, Austria, Germany and Italy. Not only did he inspect these rivers personally and discuss their control with the authorities and engineers in charge, but he brought back with him detailed maps of each major river, with reports of their past history and behaviour, the control methods adopted and any adjustments later experience required. Similar procedure was also adopted when investigating the Mississippi River in America.
While overseas Mr Nelson also devoted time to the study of English and Continental harbour and to the dikes system of control of tidal and estuary waters in Holland.
Mr Nelson’s accumulated technical books on these matters, his engineering journals, copies of official reports and detailed plans of all these overseas river and harbour matters, plus copies of his own New Zealand river and harbour reports and supplementary writings, have been gratefully received by New Zealand’s foremost school of engineering and the McMillan-Brown National Collection of New Zealand Material. His river and Inner Harbour plans for Hawke’s Bay, with supplementary writings, are now preserved in the Hawke’s Bay Art Gallery and Museum.
In his article last Saturday the Rev. Quentin Nelson mentioned his father’s brilliance as a civil engineer. Mr George Nelson pioneered important developments in refrigeration equipment and took a prominent part in the establishment of cool storage in Hawke’s Bay. His foresight and advocacy, including preliminary surveys were largely responsible for the Waikaremoana electric power scheme.
He supervised drainage and reclamation of large areas of Napier, including diversion of the Tutaekuri River and designed a special dredge for this work. Various local bodies throughout New Zealand engaged Mr. Nelson to report on different river control schemes, one of these being the Waimakariri River, North Canterbury. His report and recommendations for this river received the commendation of world authorities.
On the question of shipping facilities for Napier, Mr Nelson developed plans for a naturally-protected inner harbour at Ahuriri, as against others who favoured an outer breakwater harbour. The inner harbour proposal was endorsed by overseas engineers and carried by public vote but the 1914-18 war and subsequent delays and revived controversy held this up until the 1931 earthquake, after which the outer breakwater harbour was proceeded with. The present difficulties through scouring underneath the breakwater were among those foreseen by Mr Nelson.
Thus, from such an unique background of personal experience and practical capacity was developed the comprehensive river control plan of the late Mr George Nelson.
The Hawke’s Bay Catchment Board’s engineer – whose own first choice, we must in fairness remember, was a more comprehensive plan than the present one – has already remarked on the need for adjustments in the future. So the people of the district may well repeat his son’s question, “Should Mr Nelson have been listened to more attentively?”