Taupo District Flood Hazard Study - Whareroa Stream June 2012

Taupo District Flood Hazard Study - Whareroa Stream
Pumice soils are the dominant soil type in the Whareroa catchment; with immature orthic
pumice soils covering the greatest area (43.2%). These soils have low clay content and are
mostly gravelly or pumice sand. The soils have low natural and disturbed strength, high
macroporosity, and deep rooting depth. The soils on the slopes of the upper catchment are
predominately humose orthic podzols (12.2%). Podzol soils often occur in areas of high
rainfall, and have low fertility, low base saturation, and are strongly acidic. Welded impeded
pumice soils (8.4%) occur where there is a subsoil layer that restricts the movement of water
and roots. Allophanic soils are also found in the Whareroa catchment; typic orthic (2.7%),
and acidic orthic (4.6%). These soils are dominated by allophane minerals and are
predominantly found in volcanic ash and weathered volcanic rocks. The soil is porous with a
low density structure and weak strength (Figure 2.3).
Figure 2.3:
Soils of the Whareroa catchment.
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