Author: Dr Douglas Hicks
This report summarises the results of a survey carried out in May-June 2005. The survey's purpose is to ascertain the extent of vegetative soil conservation cover in the Mangarama catchment, and measure what reductions have accrued from them. This information is required for a five-year review of soil conservation in the Upper Waipa sub-catchments.
The Mangarama catchment has been selected by Environment Waikato staff because they regard it as typical of the Upper Waipa sub-catchments in its terrain, land use, and soil conservation measures.
It is 59 square kilometres in extent, draining north from the Mokau watershed near Te Kuiti and entering the Mangapu, a slightly larger tributary of the Waipa. The western headwaters are an undulating limestone plateau full of sinkholes and caves, with surface drainage in valley bottoms where streams have cut down to underlying greywacke.
West of the Waipa fault, mudstone is dissected into moderate footslopes descending from the limestone plateau to the catchment's middle reaches which are a broad valley floor infilled by alluvial terraces, floodways and drained swamps. The Mangarama's eastern and southern rims are short steep hill country, formed from alternating beds of mudstone, sandstone and limestone.
All landforms in the catchment are mantled by volcanic ash - patchy on the hills, deep on the plateau and footslopes, re-sorted by water on the terraces and floodways.
The survey brief is to :
Soil Conservation Survey of the Mangarama Catchment
(111 kb, 15 seconds to download, 56k modem)
|Changes in the catchment between 1992 and 2002||13|
|Need for conservation measures||14|
|Extent of measures||14|
|Adequacy of measures||15|
|Erosion under different types of conservation measure||15|
|Erosion under different standards of conservation measure||16|
|Soil disturbance by land use||16|