Long Term Water Quality Trend Analysis

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) .

baytrends

Windows Linux OSX

The baytrends package was developed to enable users to evaluate long-term trends in the Chesapeake Bay 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. This approach, which is fully transferable to other systems, allows for Chesapeake Bay water quality data to be evaluated in a statistically rigorous, yet flexible way to provide insights to a range of management- and research-focused questions.

Installation

The CRAN version of baytrends from CRAN can be installed with the code below.

install.packages("baytrends")

In some cases not all dependent packages are available on the user’s system. In these cases installing all dependencies is necessary.

install.packages("baytrends", dependencies = TRUE)

The development version (with vignettes) from GitHub can be installed with the code example below using the remotes package.

if(!require(remotes)){install.packages("remotes")}  #install if needed
install_github("tetratech/baytrends", force = TRUE, build_vignettes = TRUE)