Report: TR 2010/02

Author: Max Gibbs, NIWA

Abstract

Waikato Regional Council requires information on near-shore water quality as distinct from the mid-lake water quality obtained from the long-term routine monitoring at the mid-lake site (Site A) by NIWA to enable comparisons between open water and near-shore water quality. This report provides the cumulative water quality and algal enumeration data for the period from January 2007 up to June 2009, from site A (mid lake) and two near-shore sites, Whangamata Bay (Kinloch) and Whakaipo Bay. This report evaluates to what extent the water quality at these two near-shore sites is similar to that at Site A. Of specific interest are the differences, if any, between total nitrogen concentrations and water clarity (Secchi depth) at the near-shore sites compared with the mid-lake site, and the similarities between seasonal patterns in the data. Additional data from Acacia Bay over the same period are included for comparison as required.

The physical and chemical data were graphed as time-series over the 2-year monitoring period to show seasonal cycles and identify trends in the data. Differences between near-shore and mid-lake data were assessed by subtracting the mid-lake data from the near-shore data. The resultant difference values were then either greater or less than the mid-lake values and could be assessed for consistency and the presence of seasonal or other cyclicity and trends. These difference data were also used to assess any differences between the two near-shore sites.

Lake Taupo Near-Shore Water Quality Monitoring 2007-2009 [PDF, 789 KB]