Download, import and visualize flow data from CHEQ 🌊

Files downloaded from Centre d'Expertise Hydrique du Québec (CEHQ) are messy. The header contains useful information, but this information is not well organised. The table with values appears a couple of lines below the header. In this project, we share some functions that we've written to allow downloading, importing, tidying and visualizing flow data from CEHQ website.

Disclaimer : The authors are not affiliated to any govermental organizations.

Step 1 : Download data

See R script R/s1_data_download.R for a complete example.

# Fetch stations.
stns <- fetch_stns(1L)  # Id of the region.

# Download stations.
download_stns_files(stns$No_de_la_station)

Step 2 : Import and plot data

See R script R/s2_import_and_plot_data.R for an example.

# Load table.
tbl <- read_table(path)

# Load station information.
info <- read_info(path)

# Plot full series.
plot_flow_series(tbl, info)

# Plot series with NA.
plot_flow_series(tbl, info, spot.na = TRUE)

# Plot subset of the series.
plot_flow_series(tbl, info, start = "2018/01/01", end = "2020/12/13")

# Plot POT.
plot_flow_pot(tbl, info, thresh = quantile(tbl$FLOW, 0.99))

Step 3 : Explore missing values.

See R script R/s3_explore_missings.R for an example.

# To be completed...

Results

Full flow series of Sainte-Marguerite river :

Subset of the flow series of Sainte-Marguerite river :

Full flow series of Chicoutimi river with NAs :

Subset of the flow series of Chicoutimi river with NAs :

Overview of missing values :

Peaks-over-threshold for the full Chicoutimi river flow series :

Peaks-over-threshold for the last five years of the Sainte-Marguerite river :

Enjoy ! ✌🏻