To cite package ‘waterYearType’ in publications use:

  Gill S (2019). _waterYearType: Sacramento and San Joaquin Valley
  Water Year Types_. R package version 1.0.1,
  <https://CRAN.R-project.org/package=waterYearType>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {waterYearType: Sacramento and San Joaquin Valley Water Year Types},
    author = {Sadie Gill},
    year = {2019},
    note = {R package version 1.0.1},
    url = {https://CRAN.R-project.org/package=waterYearType},
  }