North American Stream Hydrographers [NASH] Special Issue

The North American Stream Hydrographers (NASH) was conceived as a vehicle for bringing researchers and practitioners together in a community of practice for advancing the science of hydrometry and for the development and communication of best practices to keep apace with the rapid advances in monitoring technology. While many hydrometric programs and agencies, such as the World Meteorological Organization, are engaged in the development of standard operating procedures for stream gauging, there is currently no organization solely dedicated to providing leadership in advancing the science of stream hydrography and, more specifically, hydrometry. The need for science leadership in hydrometry has never been greater than it is right now. Hydrometry is largely a technology-driven enterprise; the demand for improved accuracy, reliability, and timeliness of hydrometric data drives the early adoption of emerging techniques, technologies and methodologies.

Today, practitioners are faced with a need to make the activity of monitoring cheaper, safer, and more environmentally benign, while improving the result of monitoring with information-rich, comprehensive, reliable, inter-comparable, and timely data products. The prudent practitioner wants to optimize these factors against a host of available and emerging techniques, technologies, and methodologies to find a solution that is most appropriate for local conditions. Such changes can provide improved data if used with appropriate expertise in favourable conditions. Unfortunately, field conditions vary widely and the expertise of the hydrometric practitioner necessarily lags behind the implementation of technological advances resulting in an unknowable pattern of uncertainty in any hydrometric time series. The cumulative effect of monitoring decisions that are individually intended to improve the efficiency of the data collection and the quality of the data have an unintended consequence of degrading some of the value of the data at a variety of time scales relevant in water management.

Kolupaila (1961) listed 7,370 titles in his annotated bibliography covering work published in more than 30 languages. Today, that number is likely to be orders of magnitude greater. A Google search on the term hydrometry yielded 210,000 results (on Sept. 28, 2011) after eliminating results referring to a hydrometer, a device for measuring specific gravity. This number illustrates only one strand of the difficulty experienced by practitioners in connecting their particular needs to the most relevant and recent research. The best research on field methods and on the reduction and management of hydrometric data uncertainty is often reported in obscure government documents or scattered amongst the journals of many diverse disciplines.

Water resources management endeavours to resolve many wicked problems. Problems are wicked if: (1) the consequences of error are severe; (2) there are multiple contradictory or antagonistic objectives; (3) tools are inadequate with respect to process understanding and/or description of current conditions, and the assessment of uncertainty; and (4) the complexity, non-linearity, and inter-dependencies of the system exacerbate the likelihood of unanticipated outcomes. The effort to solve one wicked problem often reveals-and sometimes creates-other problems. One of the few, manageable factors that can help render a wicked problem a tractable one is good data. Data can be adequate by design, but the selection of the best techniques, technologies, and methodologies to produce adequate data has to be informed by the best available science.

The papers in this special issue were presented at the NASH workshop held in conjunction with the 2010 National CWRA Conference in Vancouver. Of the many papers and posters presented at this workshop, four were prepared for submission to the Canadian Water Resources Journal and follow in this issue. These papers received the normal reviewing and editing procedure led by the Guest Editors and the Journal Editors with the help of anonymous referees, for which we are very grateful. In this issue, Hamilton and Moore (2012) argue that the utility of hydrologic information would be enhanced by the quantification and publication of uncertainty estimates for streamflow data, and provide recommendations for moving toward this goal. Dow-Ambtman and Hicks (2012) discuss the difficult hydrometric task of estimating peak floods that result from ice jams. Guay et al. (2012) provide a specific case study demonstrating how the improvements in hydroacoustic Doppler technology have affected the quality of winter hydrometric data quality. Lastly, Whitfield (2012) discusses the importance of understanding how environmental data are collected over time and the repercussions for hydrologic analysis. Together, these four papers demonstrate some aspects of the importance and relevance of hydrometric practice and the work of NASH.