Natural waterways form an integral part of the urban and rural environment. In New Zealand, their uses are generally related to agriculture, drainage, power generation and recreation, but their value also extends to providing ecological services that are vital to the maintenance of a fully functioning environment. In the areas of the world that are considered to be developed, several functions and services that waterway systems initially would have provided, have been degraded, or lost completely, due to water abstractions, altered flow regimes and input of pollutants.

In New Zealand, and around the world, groups of volunteers give up their time in order to help monitor the quality and state of waterways. However, there remains a distrust of data generated by such groups throughout the scientific community. This concern is also voiced by members of these groups, querying what the point of their monitoring is, if the data has no real use. As a result of this uncertainty about the data quality and its subsequent uses, data is often just entered onto a database with little, or no, analysis conducted.

The purpose of this research was to ascertain the quality of the data generated by volunteers groups in New Zealand by comparing it with data collected by professionals from city and regional councils. Volunteer monitoring methods and tools were also compared with those available to professionals in order to determine if any differences observed were a product of equipment, or other factors. However, data generation is not the only purpose of these volunteer groups. By being involved, volunteers are gaining education, practical skills and knowledge they may not have access to otherwise, and they are meeting people and strengthening community ties. Volunteers from each group therefore also completed a survey to determine their knowledge of the programme they participate in, of the environment and freshwater, and to collect some basic background information. The Styx Living Laboratory Trust (SLLT) in Christchurch, the Wakapuaka Rivercare Group in Nelson and Wai Care in Auckland were the three New Zealand community water monitoring groups chosen to be the subject of this study.

Generally, the volunteer conductivity and pH data was significantly different from that of their professional counterparts, with large differences obvious in the data sets from all three groups. Water temperature was the only variable that was consistently similar for volunteer and professional data. Comparison of the SLLT’s methods with professional-level methods, however, revealed that differences in the data sets may be due to a combination of factors including equipment (e.g., use of pH colour strips instead of meters), and variation in the monitoring protocols, rather than a lack of quality in the volunteer data. However, new dissolved oxygen and nitrogen monitoring methods utilised by Wai Care did produce some promising results, with some of the comparisons unable to be statistically differentiated from the professional data set.

Visual assessment of the SLLT data over time suggests seasonal patterns in pH and conductivity, and possible increases in water clarity over time. Statistical analysis of the individual variables of pH, water temperature, clarity and conductivity, in the SLLT data revealed several significant predictors and interactions, including time, date and pH among other things. However, the very small effect size and the large data set suggest this may just be a product of the large data set with very few of these variable interactions having any real meaning with regards to management.

Volunteers were predominantly over the age of 40, and were generally either very new recruits to their monitoring programmes (<6 months) or had been involved for a reasonably long time (>5 years). There were differing patterns of involvement between the groups with the WRG having volunteers mainly involved for >10 years while the SLLT had a large number of new recruits. There were also varying reasons volunteers chose to become involved however, the predominant reason was concern for the environment.

Approximately half of the volunteers surveyed proved to be very knowledgeable about their programme and understood the purposes of the monitoring programme, although most were associated with a science-related industry and therefore likely already had this knowledge. More education and training would be needed to bring all of the other volunteers up to this level. All volunteers had good knowledge of issues in New Zealand’s environment and freshwater currently face, with public apathy considered the most pressing issue.

In summary, despite the lack of clear statistical similarities between volunteer and professional data sets for some variables, the data do not appear to be randomly inaccurate and could be corrected to be combined with professional data. The benefits the volunteers gain appear to outweigh any issues that may be present in the data, as long as the volunteers perceive the data to be ultimately useful. Volunteer-based water quality monitoring has proved to be a valuable way to gather environmental data, educate the community and improve their commitment to local waterways.