To do a comprehensive search of the journal literature on your topic, you must use journal indexes. The full-text journal databases on Lexis and Westlaw do not contain all of the law journals published, and, for those that are included, the starting date of coverage is rarely volume 1.
The journal indexes, in contrast, include virtually all legal journals from volume 1 and, in the case of the Legal Resource Index, legal newspapers as well.
For research on water law prior to 1980, older journals can provide excellent background information and discussions of policy issues.
Some specialized journals on the topic of water law include:
Land and Water Law Review - University of Wyoming (ceased publication in 2000)
Water Law Review - University of Denver
Wyoming Law Review - replaced Land and Water Law Review