Regional flood estimation in New Zealand.

By: Beable, M. E.
Contributor(s): McKerchar, A. I. (Alistair Ian), 1945-. (Ministry of Works and Development, Water and Soil Division, Christchurch Science Centre. Christchurch) | New Zealand. Water and Soil Division.
Material type: materialTypeLabelBookSeries: Water & soil technical publication ; no. 20.Publisher: Wellington, N.Z. : Water and Soil Directorate, Ministry of Works and Development, 1982Description: 132 p. : 33 tables; 51 figs ; 30 cm.ISSN: 0110-4144.Subject(s): FLOODS | DATA ACQUISITION | NORTH ISLAND | SOUTH ISLAND | FLOW MEASUREMENT | MATHEMATICAL MODELS | FREQUENCY DISTRIBUTION | STATISTICAL ANALYSISHoldings: HAMILTON: S 622 WAT TEC/20 Online resources: Click here to access online In: Water & soil technical publicationAbstract: Extreme value type I (Gumbel) and type II distributions are fitted to annual flood peaks from 152 recording stations throughout New Zealand. By grouping catchments with similar flood frequency attributes, eight regions are suggested. These flood frequency regions tend to correspond with climatic regions. Further, after grouping all the eastern and all the western catchments into two larger flood frequency regions, there was enough data in each region to develop master curves that are extrapolated to T = 1000 years. These curves resemble curves drawn for catchments in eastern and western parts of the British Isles. Multiple regression equations are obtained for estimating Q as a function of catchment area and one or two catchment rainfall parameters. Single equations applied in each island have prediction errors which show geographical patterns. Thus nine mean annual flood regions are defined which tend to correspond to lithologic and climatic regions, and a regional equation is suggested for each. These equations and the regional curves are the foundation of a suggested design flood estimation method, which is illustrated with examples
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Item type Current location Call number Copy number Status Date due Barcode
BOOK BOOK HAMILTON
STACK
S 622 WAT TEC/20 1 Available 122932-1001
JOURNAL JOURNAL WELLINGTON
STACK
STACK NO. 20 1982 1 Available J010806

65 refs; 6 appendices (35 refs)

Extreme value type I (Gumbel) and type II distributions are fitted to annual flood peaks from 152 recording stations throughout New Zealand. By grouping catchments with similar flood frequency attributes, eight regions are suggested. These flood frequency regions tend to correspond with climatic regions. Further, after grouping all the eastern and all the western catchments into two larger flood frequency regions, there was enough data in each region to develop master curves that are extrapolated to T = 1000 years. These curves resemble curves drawn for catchments in eastern and western parts of the British Isles. Multiple regression equations are obtained for estimating Q as a function of catchment area and one or two catchment rainfall parameters. Single equations applied in each island have prediction errors which show geographical patterns. Thus nine mean annual flood regions are defined which tend to correspond to lithologic and climatic regions, and a regional equation is suggested for each. These equations and the regional curves are the foundation of a suggested design flood estimation method, which is illustrated with examples

HAMILTON: S 622 WAT TEC/20

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