Land Use In Thermal Areas To Be Controlled

Taupo Times, Volume XIV, Issue 67, 26 August 1965, Page 6

Land Use In Thermal Areas

To Be Controlled

The Taupo Borough Council has given full consideration to a report made by the D.S.I.R. on land use of areas in the borough which are subject to geothermal activity and has decided on a policy in relation to the issue of building permits in future. This action was taken Monday's of the council after a lengthy report and recommendation from the works committee had been discussed. The recommendation that possible effect of activity in the areas, and building precautions, should be brought to the notice of persons applying for building permits, and also the Lands and Survey Department, was adopted.

Since receipt of the report the council has sought the opinion of the Ministry of Works on several issues and these were given in a letter received from the District Commissioner of Work, Mr McLeod, which were taken into consideration by the works committee in making their recommendation. Briefly, these were that the council should exercise restraint only in regard to information contained in the report, and should discuss further Crown land development with the Land and Survey Department. Mr McLeod advised that very careful consideration had been' given to the report by interested Government departments and that considerable discussion had taken place between them. Possible effects of using "hot" areas were given as follows: • Steam and gas emissions could cause accelerated decay of building materials and possible risk to occupants. • Foundation conditions could be variable as the ground is unstable. Geothermal action could cause the formation of tomos and the leaching out of soil eonstituents. • Changes in ground water fiow inside hot areas could result in blow-outs or geothermal explosion. The likelihood of this was uncertain, but must be considered as a possibility.

9 Instability of the geothermal source could result in an increase or decrease of surface activity. While no more detailed prediction of future activity could be made, it was considered wise to accept the above as possibilities, and that reasonable precautions should be taken in building design and land use. These were listed as: 9 Materials should be chosen after considering the possible effects of heat, steam and gases. • Ventilation should be provided to lead off ground emission and to provide maximum dilution with fresh air. Design should avoid the creation of pockets which would be dangerous if filled with gas.

® Foundations should be designed with regard for the possibility that ground support may be lost under some portions of structures. ® Ground water changes should be kept to a minimum and this requirement should be considered in the layout of paving, buildings, drainage and the discharge of storm water. The above possible effects and recommended precautions are those which the council will bring to the notice of applicants for building permits, It was also pointed out by ,Mr McLeod that the precautions to a certain extent would determine the types of land use reasonable in hot areas. He considered that it would be wise in any case, to avoid dense

population or the erection of buildings designed for use by large numbers of people. * At Monday's meeting of the council, Cr W. L. Haines said he judged from the re- v* port that the department had turned the matter over to the council. "They have pointed out the risks which council will have to make suitable by-Iaws to cover," he said. Cr D. Davis suggested to r the meeting that people who contemplated building in the area should have their attention drawn to the building requirements. He thought it advisable to have special zoning adopted so that intending builders * would have some guidance. The town clerk, Mr K. G. Winton, said he had some misgivings about restricting the area as it could cause deiay and cost to some businesses. ^ Cr C. J. N. Newbold commented that sufficient harm had been done by "irresponsible enlargement of the problem" and he thought that making the area a special zone would aggravate the r situation. The Rotorua county engineer, Mr R. S. Martin, said ^ a similar system was prac- * tised in the county. The Rotorua City Council engineer, Mr D. C. A. List, said that the code adopted by Taupo borough was fairly much in line with what was already practised in Rotorua,