For citations of package itself and publication describing package, respectively:

Aho K, Ramos R, Legg A, Hale RL, Kraft M, Bond CT (2023). streamDAG: Analytical Methods for Stream DAGs. R package version 1.5, https://CRAN.R-project.org/package=streamDAG.

Aho, Ken, Kriloff, Cathy, Godsey, E S, Ramos, Rob, Wheeler, Chris, You, Yaqi, Warix, Sara, Derryberry, DeWayne, Zipper, Sam, Hale, L R, others (2023). “Non-perennial stream networks as directed acyclic graphs: The R-package streamDAG.” Environmental Modelling and Software, 167, 105775.

Corresponding BibTeX entries:

  @Manual{streamDAG-package,
    title = {streamDAG: Analytical Methods for Stream DAGs},
    author = {Ken Aho and Rob Ramos and Arya Legg and Rebecca L. Hale
      and Maggi Kraft and Charles T. Bond},
    year = {2023},
    note = {R package version 1.5},
    url = { https://CRAN.R-project.org/package=streamDAG},
  }

  @Article{,
    title = {Non-perennial stream networks as directed acyclic graphs:
      The R-package streamDAG},
    author = {{Aho} and {Ken} and {Kriloff} and {Cathy} and {Godsey}
      and Sarah E and {Ramos} and {Rob} and {Wheeler} and {Chris} and
      {You} and {Yaqi} and {Warix} and {Sara} and {Derryberry} and
      {DeWayne} and {Zipper} and {Sam} and {Hale} and Rebecca L and
      others},
    journal = {Environmental Modelling and Software},
    volume = {167},
    pages = {105775},
    year = {2023},
  }