Environmental flow requirements setting: Desktop methods

Abstract

Desktop approaches to setting environmental flow requirements (EFRs) have the potential to be useful in situations where resources (time, expertise, and information) are limited, but they will almost always provide estimates with lower confidence, or higher uncertainty, than more comprehensive assessments. There is a continuum between desktop approaches, rapid methods based on limited data collection, and comprehensive assessments involving field collection (and interpretation) of hydraulic, geomorphological, and biotic data. Under most situations, the resources required increase, and the confidence decreases, along the continuum. However, the decrease in confidence could be lower in poorly understood and complex systems because even comprehensive studies will be subject to resource constraints. Similarly, the confidence of desktop or rapid assessments could be increased given the availability of appropriate regional information and given that such information can be used within the less resource-intensive methods.