Comparing flow peaks at neighbouring stream gauges. See Blog https://tonyladson.wordpress.com/2018/12/04/comparing-peaks-at-stream-gauges/

gistfile1.txt

library(tidyverse)
library(scales)
library(lubridate)
library(ggrepel)

# Fifteen Mile Creek and Boggy Ck
#
# The gauges are:
# Fifteen Mile Creek at Greta South (403213)
# Boggy Creek at Angleside (403226)

# Data obtained from WMIS - Water Measurement Information System
# http://data.water.vic.gov.au/monitoring.htm

# Data is at
#  https://drive.google.com/open?id=1afzZH4Vi97_-_5hSdkEEhOvzNgEW2lzL

# This provides the min, mean and max flows at the two gauges for a number of years
# Fifteen Mile Ck at Greta south 1958 - 2016
# Boggy Creek at Angleside 1968 - 2017


# Read data from google drive ---------------------------------------------


id <- "1afzZH4Vi97_-_5hSdkEEhOvzNgEW2lzL" # google file ID
flow <- read_csv(sprintf("https://docs.google.com/uc?id=%s&export=download", id),
              skip = 20,   
              col_names = FALSE)

# Process the file

flow <- flow %>% 
  select(c(1,6,12)) %>%  # Select date, annual max for each gauge
  rename(xdatetime = X1, # year of maximum
         Fifteen_mile = X6, # Annual maximum
         Boggy = X12) %>% # Annual maximum
  mutate(xdatetime = lubridate::dmy_hm(xdatetime)) %>%  # convert the date to R format
  mutate(xyear = lubridate::year(xdatetime)) # extract the year from the date

# Time series barplot

p <- flow %>% 
  select(xyear, Fifteen_mile, Boggy) %>% 
  filter(xyear %in% c(1980:1990)) %>% 
  gather(-xyear, key = 'Creek', value = 'annual_peak') %>% 
  ggplot(aes(x = factor(xyear), y = annual_peak, fill = Creek)) +
  geom_bar(stat = 'identity', position = 'dodge') +
  scale_fill_hue(name = NULL, l = 40, labels = c('Boggy Ck', 'Fifteen Mile Ck')) +
  scale_x_discrete(name = 'Year') +
  scale_y_continuous(name = 'Annual peak flow (ML/d)', labels = scales::comma) +
  theme(legend.position = c(0.9, 0.9)) +
  theme(legend.position = 'bottom', text = element_text(size = 8))

p

#ggsave("../figures/peak_barplot.png", p, width=4, height=3)



# Points representing paires of values

p2 <- flow %>% 
  filter(xyear %in% c(1980:1990)) %>%  # extract a sub-set of the data
  ggplot(aes(x = Fifteen_mile, y = Boggy)) +
  #geom_line() +
  geom_point(size = 1) +
  geom_abline(slope = 1, intercept = 0, linetype = 'dashed', alpha = 0.3) +
  scale_x_continuous(name = 'Fifteen Mile Ck (ML/d)', labels = comma, limits = c(0,11000)) +
  scale_y_continuous(name = 'Boggy Ck (ML/d)', labels = comma, limits = c(0,11000)) +
  geom_text_repel(aes(label = xyear), size = 2, min.segment.length = 0.2, segment.size = 0.2) +
  theme(text = element_text(size = 8))

p2

#ggsave("../figures/peak_pair_comparison.png", p2, width=4, height=3)