Hydrological Sciences has perhaps three important characteristics that, whilst not perhaps unique in terms of scientific context, are of particular relevance to the proposed initiative to develop a definitive research level multi-volume encyclopedia of the subject. Firstly, the field of Hydrological Sciences is of particular importance in that the process underpinnings that relate to the movement of water from the atmosphere, through and on hillslopes, rivers and floodplain environments are themselves central to related sciences such as ecology, climatology etc. Secondly, hydrological science is a rapidly evolving and developing area but there is a lack of an inclusive reference source that offers an innovative approach melding together information on hydrological processes from sub-catchment to the global scale. Finally, many users and scientists increasingly require software that encapsulates the science of the hydrological problem in a convenient and scientifically credible manner. This exciting project acknowledges these three major elements of the science, and seeks to develop a definitive, research level encyclopedia with software access.  

The majority of the entries are substantial articles (up to 10,000 words). Such articles occupy approximately 10-15 pages in the printed Encyclopedia, including illustrations, black and white photographs, figures, tabular material and accompanying reference list. Accordingly such articles of this type will be of the status of short scientific papers.