The 1990s represented an interesting decade in the life of the Red and Assiniboine rivers in Winnipeg, MB. The first couple years of the decade were characterized by below average water levels, which all changed in 1997 with ‘the flood of the century’.

The impacts of these events are still evident in Winnipeg today. The walkways along the river, built in the early 1990s, are set close to the water and flood more frequently than initially projected. The flood of 1997 didn’t cause significant damage within the city of Winnipeg, but it led to the city further excavating the Red River Floodway to add additional capacity for future floods of that magnitude.

Water level summary by year

Looking at the mean and max water levels by year, you can see how 1990 and 1991 were well below average, and 1997 was a significant flood event compared to other years.

# This is a normal code chunk
# By default, both the code and its output will appear in the knit document
# The hash marks in front of the codes output have been disabled for a cleaner appearance

# Download the historic water levels for the Red River in Winnipeg
levels <- read.csv('https://data.winnipeg.ca/resource/q8w3-jhjb.csv?$limit=3650&$offset=0')

# Print a summary table by year for 1990 to 1999
levels %>% 
  filter(substr(reading_date, 1, 3) == '199') %>%
  group_by(substr(reading_date, 1, 4)) %>% 
  summarize(Observations = n(), Mean = mean(james_feet), Min = min(james_feet), Max = max(james_feet)) %>%
  rename(Year = `substr(reading_date, 1, 4)`)
# A tibble: 10 x 5
   Year  Observations  Mean   Min   Max
   <chr>        <int> <dbl> <dbl> <dbl>
 1 1990           357  2.98 -2.5    6.8
 2 1991           364  2.76 -1.9    7  
 3 1992           365  3.95 -1.82  15.5
 4 1993           365  4.95 -0.53  16.6
 5 1994           365  5.34  1.32  14.8
 6 1995           361  6.08  0.4   17.9
 7 1996           366  6.45  1     19.3
 8 1997           365  6.72  1     24.5
 9 1998           364  6.24  0     17.1
10 1999           364  6.46  0.4   17.3

The flood of 1997

The flood of 1997 was considered a 1:100 year event. Even with the operation of the Red River Floodway, the water level in the city of Winnipeg peaked at 24.5 feet on May 3rd.

The flood caused $500M of damage within the province of Manitoba, largely within the communities surrounding Winnipeg. While the floodway was effective in limiting the water levels within the city of Winnipeg, some have criticized its design as having raised water levels in the outlying communities.