countyfloods (version 0.1.0)

run_flood: Return flood metrics by county codes or state names

Description

Access USGS databases to retrieve gages and flow data for the specified counties/states or 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.

Usage

run_flood(county_cd = NULL, state = NULL, start_date, end_date,
  threshold = "Q2", flood_type = "flood", output = "both",
  weight = "Q2")

Arguments

county_cd

Character vector with the county FIPS code(s)

state

Character vector of state names. Used to obtain county FIPS codes if county_cd is NULL

start_date

Character string with the starting date, using "YYYY-MM-DD" notation.

end_date

Character string with the end date, using "YYYY-MM-DD" notation.

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")

output

Character string of output summary type (either "gage", "county", or "both"). Defaults to "both".

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 data frame with output at either the gage or county level, depending on the value of "output". If output = "gage" a data frame with the following columns is returned:

Name	Type	Description
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

If output = "county" a data frame with the following columns is returned:

Name	Type	Description
county	character	County name
state	character	State name
num_gage	numeric	Number of analyzed gages in county
avg_peak	numeric	Average flood ratio among county gages
max_peak	numeric	Maximum observed flood ratio
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

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.

If output = "both" a list containing both data frames is returned. In both cases, if data in counties were requested but not avaialable, these counties are included as additional rows with data values of NA.

Examples

# NOT RUN {
#Use Q2 as flood threshold and get get gage-level output
va_floods <- run_flood(state = "Virginia", start_date = "2015-01-01",
                      end_date = "2015-12-31", threshold = "Q2",
                      output = "gage")

#Use NWS flood thresholds and get county-level output
va_floods <- run_flood(state = "Virginia", start_date = "2015-01-01",
                      end_date = "2015-12-31", threshold = "NWS",
                      flood_type = "action",
                      output = "county")
# }