Long Term Water Quality Trend Analysis R package baytrends version 2.0.14 CRAN Task View: Hydrology (https://CRAN.R-project.org/view=Hydrology) Enable users to evaluate long-term trends using a Generalized Additive Modeling (GAM) approach. The model development includes selecting a GAM structure to describe nonlinear seasonally-varying changes over time, incorporation of hydrologic variability via either a river flow or salinity, the use of an intervention to deal with method or laboratory changes suspected to impact data values, and representation of left- and interval-censored data. The approach has been applied to water quality data in the Chesapeake Bay, a major estuary on the east coast of the United States to provide insights to a range of management- and research-focused questions. Methodology described in Murphy (2019) <doi:10.1016/j.envsoft.2019.03.027>. Software Depends: R (>= 4.1.0) Imports: dataRetrieval, digest, dplyr, fitdistrplus, grDevices, lubridate, knitr, memoise, mgcv, pander, plyr, readxl, sessioninfo, survival, tibble, tidyr Suggests: devtools, imputeTS, markdown, nlme, rmarkdown, testthat Erik W Leppo <Erik.Leppo@tetratech.com> Comprehensive R Archive Network (CRAN) Rebecca Murphy [aut] (ORCID: <https://orcid.org/0000-0003-3391-1823>), Elgin Perry [aut], Jennifer Keisman [aut] (ORCID: <https://orcid.org/0000-0001-6808-9193>), Jon Harcum [aut] (ORCID: <https://orcid.org/0000-0001-5910-5243>), Erik W Leppo [aut, cre] (ORCID: <https://orcid.org/0000-0001-8026-7474>) GPL-3 2026-02-24 application/tgz https://CRAN.R-project.org/package=baytrends doi:10.32614/CRAN.package.baytrends