long_term_flood: Return flood metrics by county codes for a data frame input

In countyfloods: Quantify United States County-Level Flood Measurements

Description

Access USGS databases to retrieve gages and flow data for the specified county FIPS codes and the specified date ranges. Flooding at these gage locations are assessed by one of two metrics. Data can be returned at the gage level or the county level. This is the same as the run_flood function but accepts a data frame as input with multiple county codes and date ranges for each.

Usage

long_term_flood(input_df, threshold = "Q2", flood_type = "flood",
  weight = "Q2")

Arguments

input_df	Data frame with three columns: county_cd, start_date, and end_date
threshold	Character string of the flood threshold to be used in the analysis (either "Q2" or "NWS"). Defaults to "Q2".
flood_type	Character string of the defined flood type based on NWS classifications (one of "action", "flood", "moderate", or "major")
weight	Character string of variable to be used to scale by river size for weighted averages and scaling point sizes on maps. Options are median annual flood ("Q2") or drainage area ("DA"). Defaults to "Q2"

Value

A list with two data frames summarizing data by gage and by county.

Gage:

Name	Type	Description
start_date	date	Input start date
end_date	date	Input end date
site_no	character	USGS gage ID
county_cd	character	FIPS code of gage county location
lat	numeric	Gage latitude
long	numeric	Gage longitude
avg_peak	numeric	Mean flood ratio for date range (discharge/flood threshold)
flood_dur	numeric	Number of days in date range discharge above flood threshold
max_peak	numeric	Maximum value of flood ratio for date range (discharge/flood threshold)
num_missing	numeric	Number of days in given date range with no discharge data at that gage
Q2	numeric	Median annual discharge (cubic feet per second)
DA	numeric	Drainage area of the gage (square miles)
size	numeric	Relative river size, logarithm of either Q2 or DA depending on user specified weight
state	character	State name
county	character	County name
flood	character	Flood magnitude category based on peak

County:

Name	Type	Description
county_cd	character	FIPS code of gage county location
start_date	date	Input start date
end_date	date	Input end date
county	character	County name
state	character	State name
num_gage	numeric	Number of analyzed gages in county
max_peak	numeric	Maximum observed flood ratio
avg_peak	numeric	Average flood ratio among county gages
minor	numeric	Percentage of gages at or above "minor" flood class (flood ratio > 1)
moderate	numeric	Percentage of gages at or above "moderate" flood class (flood ratio > 1.5)
major	numeric	Percentage of gages at or above "major" flood class (flood ratio > 2)
extreme	numeric	Percentage of gages at or above "extreme" flood class (flood ratio > 5)
max_dur	numeric	Maximum flood duration in county
avg_dur	numeric	Average flood duration in county

If threshold = "NWS", the columns "minor", "moderate", "major", and "extreme" are replaced with two columns: "no_flood" and "yes_flood" which show the percentage of gages in the county with or without flooding.

Examples

## Not run: 
#Northern VA flooding every April
county_cd <- c(rep("51013", 5), rep("51107", 5), rep("51059", 5))
start_date <- rep(c("2010-04-01", "2011-04-01", "2012-04-01", "2013-04-01", "2014-04-01"), 3)
end_date <- rep(c("2010-04-30", "2011-04-30", "2012-04-30", "2013-04-30", "2014-04-30"), 3)
input_df <- data.frame(county_cd = county_cd, start_date = start_date, end_date = end_date,
                      stringsAsFactors = FALSE)

#With default values
VA_floods <- long_term_flood(input_df)

#Using NWS values
VA_floods <- long_term_flood(input_df, threshold = "NWS")

## End(Not run)

countyfloods documentation built on May 2, 2019, 2:38 a.m.