How we monitor
Randomly selected 1 km lengths of waterway from all pastoral land were selected for the monitoring. The sites are stratified by management zones, land use, and waterway size (as measured by Strahler stream order).
The monitoring occurs every five years.
The regional riparian characteristics survey was completed for the first time in 2002 and has been repeated in 2007 and 2012.
The regional riparian characteristics survey employs a sampling approach to provide scientifically robust estimates of the state of observed riparian characteristics (e.g. the proportion of bank length fenced).
A sample site is an approximately 1km long stretch of waterway in pastoral land at which the riparian characteristics (such as fencing, vegetation, and stream bank erosion) are observed along both banks. Sites and observations are spatially referenced by GPS and the data are recorded using hand-held computers.
The raw data is stored in Excel spreadsheets and saved in Waikato Regional Council’s electronic document management system. The GPS data is stored in GIS layers.
The length of each sample site (approximately 1km) is walked, adjacent to the waterway, and the riparian characteristics on both banks are observed and the data captured using a hand-held computer with built-in GPS. Changes in characteristics from those observed at the start point are recorded together with the spatial location of the change. The resulting stream segment information allows for the length and proportion of total stream length or bank length with certain characteristics (e.g. effective fencing) to be calculated. Data were collected at 385 sample sites across the region during the 2012 survey.
Proportions of bank and stream length (with associated confidence intervals) were calculated, categories compared, variables correlated, and change over time determined using appropriate statistical analysis techniques. All analyses were carried out using purpose-written macros coded in SAS Version 9.3.
Survey results in terms of the state and trend in riparian characteristics are presented for the region as a whole (i.e. region-wide), by management zone, land use (dairy and drystock), and stream order (a representation of stream size). Proportions of bank length have been presented here as graphs.
The raw data are collected using hand held computers with built-in GPS and transferred to Excel spreadsheets. The data held in Excel spreadsheets are imported into specialised statistical analysis software (e.g. SAS) for analysis. The data have been saved in GIS and Excel files stored in Waikato Regional Council’s electronic document management system.
There are no technical documents showing how the indicator data is quality assured but calibration of field observations and checking procedures for data accuracy is built into the methodology.
This indicator is not an actual measure of stream bank vegetation at every length of stream. It is a stream length sample method that provides estimates for management zones and the region as a whole.