Peak flow data from USGS (NWIS)

Description

Reads peak flow from NWISweb. Data is retrieved from http://waterdata.usgs.gov/nwis. In some cases, the specific date of the peak data is not know. This function will default to converting the complete dates, dropping rows with incomplete dates. If those incomplete dates are needed, set the 'asDateTime' argument to FALSE. No rows will be removed, and no dates will be converted to R Date objects.

Usage

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readNWISpeak(siteNumbers, startDate = "", endDate = "", asDateTime = TRUE,
  convertType = TRUE)

Arguments

siteNumbers

character USGS site number(or multiple sites). This is usually an 8 digit number.

startDate

character starting date for data retrieval in the form YYYY-MM-DD. Default is "" which indicates retrieval for the earliest possible record.

endDate

character ending date for data retrieval in the form YYYY-MM-DD. Default is "" which indicates retrieval for the latest possible record.

asDateTime

logical default to TRUE. When TRUE, the peak_dt column is converted to a Date object, and incomplete dates are removed. When FALSE, no columns are removed, but no dates are converted.

convertType

logical, defaults to TRUE. If TRUE, the function will convert the data to dates, datetimes, numerics based on a standard algorithm. If false, everything is returned as a character

Value

A data frame with the following columns:

Name Type Description
agency_cd character The NWIS code for the agency reporting the data
site_no character The USGS site number
peak_dt Date Date of peak streamflow
peak_tm character Time of peak streamflow as character
peak_va numeric Annual peak streamflow value in cfs
peak_cd character Peak Discharge-Qualification codes (see comment for more information)
gage_ht numeric Gage height for the associated peak streamflow in feet
gage_ht_cd character Gage height qualification codes
year_last_pk numeric Peak streamflow reported is the highest since this year
ag_dt Date Date of maximum gage-height for water year (if not concurrent with peak)
ag_tm character Time of maximum gage-height for water year (if not concurrent with peak)
ag_gage_ht numeric maximum Gage height for water year in feet (if not concurrent with peak)
ag_gage_ht_cd character maximum Gage height code

There are also several useful attributes attached to the data frame:

Name Type Description
url character The url used to generate the data
queryTime POSIXct The time the data was returned
comment character Header comments from the RDB file
siteInfo data.frame A data frame containing information on the requested sites

See Also

constructNWISURL, importRDB1

Examples

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siteNumbers <- c('01594440','040851325')
## Not run: 
data <- readNWISpeak(siteNumbers)
data2 <- readNWISpeak(siteNumbers, asDateTime=FALSE)
stations<-c("06011000")
peakdata<-readNWISpeak(stations,convertType=FALSE)

## End(Not run)

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