flood_analysis: Compute flood statistics
In countyfloods: Quantify United States County-Level Flood Measurements

Description Usage Arguments Value Examples

Takes flow data and computes flood statistics based on selected flood threshold.

1 2	flood_analysis(flow_data, peaks, gages, county_cd, q2_val = data.frame(site_no = "", q2 = NA, stringsAsFactors = FALSE), threshold, weight = "Q2")

`flow_data`	A data frame with discharge data for each USGS gage found for the specified data range. Output from `get_flow_data` function.
`peaks`	A data frame of USGS gage IDs and flood values obtained from either the `find_Q2` or `find_NWS` function.
`gages`	A data frame of all USGS gages and metadata obtained from the `get_gages` function. This input is used to add lat/long and county codes to the summarized output.
`county_cd`	Character vector with the county FIPS code(s)
`q2_val`	A data frame with values of the median annual flood to be used to compare relative sizes of streams at gage locations
`threshold`	Character string of the flood threshold to be used in the analysis (either "Q2" or "NWS"). Used to determine which type of summary statistics to compute.
`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".

A data frame with the following columns:

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 with missing discharge data from input date range
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

## Not run: 
va_counties <- get_county_cd("Virginia")
va_gages <- get_gages(va_counties, start_date = "2015-01-01",
                      end_date = "2015-12-31")
va_flow_data <- get_flow_data(va_gages, start_date = "2015-01-01",
                      end_date = "2015-12-31")
va_peaks <- find_q2(va_gages$site_no)
va_stats <- flood_analysis(flow_data = va_flow_data, peaks = va_peaks,
                       gages = va_gages, county_cd = va_counties, threshold = "Q2")

## End(Not run)