The river values assessment system: volume 1: overview of the method, guidelines for use and applications to recreational values

Abstract

Many attempts over several decades have been made to develop priority lists of important rivers for different values (e.g., angling, kayaking, irrigation, native birds) in New Zealand. Apart from one or two of these most have lacked clear methods, have been data poor, have been ad hoc, and perhaps worst of all, have not been standardised to provide a method that could be applied to all values. It was within this context and with demonstrable Resource Management Act and related policy demands for such lists, that Tasman District Council sought to have a tool that would construct such lists developed. A review of the literature found that no method existed that could undertake this task, but that Multi Criteria Analysis provided a possible means forward. The River Values Assessment System (RiVAS) is a Multi Criteria Analysis based tool that enables any set of rivers to be prioritised for any specified value. The key elements of the tool are: It is expert panel based and uses the best available information – in some cases this will mean almost no quantitative scientific information (e.g., river swimming), while in others it will be mainly based on scientific data (e.g., native birds); The primary attributes and a key indicator of each for the value have to be identified and populated – these need to range from between 6-10 for manageability; Thresholds of high, medium, low relative significance need to be defined for each attribute’s indicator – these are then converted to numeric scales of typically 3 to 1 for high to low respectively; The sum of these numeric scores (sometimes weighted where particular criteria are more or less important than others) then forms the basis for the comparative importance ranking of this value between rivers; Predetermined criteria to define national, regional or local importance, or high, medium or low importance (depending on the value and related legal/policy issues) are then used to perform the ranking exercise; The end result is a list of ranked rivers (or segments depending on the value) for that value. The method has now been applied to multiple values in multiple regions, with a focus on repeat applications within Tasman District Council. This two volume report outlines the method used, provides a set of guidelines for its further implementation, and then provides multiple demonstrations of it in action. Through the course of these demonstrations the changes that have occurred are documented and all are consistent with the underlying method employed.