The Waingaro River is a river of the Waikato region of New Zealand's North Island. It flows generally southwest from its origins near Glen Afton and Glen Massey, west of Ngāruawāhia, to reach a northern arm of Raglan Harbour (see 1:50,000 map). Its main tributary is Kahuhuru Stream, which Highway 22 follows for several kilometres. Tributaries total about 170 kilometres (110 mi). At Waingaro it is fed by a hot spring.
Geology
Waingaro River and hot water pump station - the pool was north of the road, but water is now pumped under the road.
The lower river flows over Puaroan age (about 150 million years ago), blue-grey Puti siltstone.
Pollution
The Waingaro River is one of the largest sources of sediment in Whaingaroa Harbour, partly because it is 99 percent unfenced.
Pollution has been worsening for phosphorus, though nitrogen has improved, as shown in this table of important (i.e. slope direction probability over 95% and RSKSE over ±1% pa) improvements, or deteriorations (-) in relative seasonal Kendall slope estimator (RSKSE) trends (monthly records are flow-adjusted using a Lowess curve fit with 30% span.) - Turbidity is also poor.
[1], [2], [3] - National Library 1910 photos of Waingaro Landing, Waingaro Bay (note the 1900 road to the Landing on the hillside) and Waingaro Estuary.
1955 Waingaro Landing aerial photo - the foreground shows part of the Kerikeri River arm of the harbour, which is over 3 km long. The Waingaro River joins the estuary in the middle left of the photo.
