1.1 Site Information

siteNumbers <- c("01491000","01645000") 
siteINFO <- readNWISsite(siteNumbers)

comment(siteINFO)

# Continuing from the previous example:
# This pulls out just the daily, mean data:

dailyDataAvailable <- whatNWISdata(siteNumbers,
                    service="dv", statCd="00003")

1.2 Parameter Information

To obtain all of the available information concerning a measured parameter (or multiple parameters), use the readNWISpCode function:

# Using defaults:
parameterCd <- "00618" 
parameterINFO <- readNWISpCode(parameterCd)

1.3 Daily Data

To obtain daily records of USGS data, use the readNWISdv function. The arguments for this function are siteNumbers, parameterCd, startDate, endDate, and statCd (defaults to “00003”). If you want to use the default values, you do not need to list them in the function call. Daily data is pulled from https://waterservices.usgs.gov/rest/DV-Test-Tool.html.

The dates (start and end) must be in the format “YYYY-MM-DD” (note: the user must include the quotes). Setting the start date to “” (no space) will prompt the program to ask for the earliest date, and setting the end date to “” (no space) will prompt for the latest available date.

# Choptank River near Greensboro, MD:
siteNumber <- "01491000"
parameterCd <- "00060"  # Discharge
startDate <- "2009-10-01"  
endDate <- "2012-09-30" 

discharge <- readNWISdv(siteNumber, 
                    parameterCd, startDate, endDate)

The column “datetime” in the returned data frame is automatically imported as a variable of class “Date” in R. Each requested parameter has a value and remark code column. The names of these columns depend on the requested parameter and stat code combinations. USGS daily value qualification codes are often “A” (approved for publication) or “P” (provisional data subject to revision).

Another example would be a request for mean and maximum daily temperature and discharge in early 2012:

siteNumber <- "01491000"
parameterCd <- c("00010","00060")  # Temperature and discharge
statCd <- c("00001","00003")  # Mean and maximum
startDate <- "2012-01-01"
endDate <- "2012-05-01"

temperatureAndFlow <- readNWISdv(siteNumber, parameterCd, 
        startDate, endDate, statCd=statCd)

The column names can be shortened and simplified using the renameNWISColumns function. This is not necessary, but may streamline subsequent data analysis and presentation. Site information, daily statistic information, and measured parameter information is attached to the data frame as attributes. This is discussed further in the metadata section.

names(temperatureAndFlow)

## [1] "agency_cd"        "site_no"          "Date"            
## [4] "X_00010_00001_cd" "X_00010_00001"    "X_00010_00003_cd"
## [7] "X_00010_00003"    "X_00060_00003_cd" "X_00060_00003"

temperatureAndFlow <- renameNWISColumns(temperatureAndFlow)
names(temperatureAndFlow)

## [1] "agency_cd"    "site_no"      "Date"        
## [4] "Wtemp_Max_cd" "Wtemp_Max"    "Wtemp_cd"    
## [7] "Wtemp"        "Flow_cd"      "Flow"

#Information about the data frame attributes:
names(attributes(temperatureAndFlow))

## [1] "names"         "row.names"     "url"          
## [4] "siteInfo"      "variableInfo"  "disclaimer"   
## [7] "statisticInfo" "queryTime"     "class"

statInfo <- attr(temperatureAndFlow, "statisticInfo")
variableInfo <- attr(temperatureAndFlow, "variableInfo")
siteInfo <- attr(temperatureAndFlow, "siteInfo")

An example of plotting the above data:

variableInfo <- attr(temperatureAndFlow, "variableInfo")
siteInfo <- attr(temperatureAndFlow, "siteInfo")

par(mar=c(5,5,5,5)) #sets the size of the plot window

plot(temperatureAndFlow$Date, temperatureAndFlow$Wtemp_Max,
  ylab=variableInfo$parameter_desc[1],xlab="" )
par(new=TRUE)
plot(temperatureAndFlow$Date, temperatureAndFlow$Flow,
  col="red",type="l",xaxt="n",yaxt="n",xlab="",ylab="",axes=FALSE
  )
axis(4,col="red",col.axis="red")
mtext(variableInfo$parameter_desc[2],side=4,line=3,col="red")
title(paste(siteInfo$station_nm,"2012"))
legend("topleft", variableInfo$param_units, 
       col=c("black","red"),lty=c(NA,1),pch=c(1,NA))

1.4 Unit Data

Any data collected at regular time intervals (such as 15-minute or hourly) are known as “unit values”. Many of these are delivered on a real time basis and very recent data (even less than an hour old in many cases) are available through the function readNWISuv. Some of these unit values are available for many years, and some are only available for a recent time period such as 120 days. Here is an example of a retrieval of such data.

parameterCd <- "00060"  # Discharge
startDate <- "2012-05-12" 
endDate <- "2012-05-13" 
dischargeUnit <- readNWISuv(siteNumber, parameterCd, 
        startDate, endDate)
dischargeUnit <- renameNWISColumns(dischargeUnit)

The retrieval produces a data frame that contains 96 rows (one for every 15 minute period in the day). They include all data collected from the startDate through the endDate (starting and ending with midnight locally-collected time). The dateTime column is converted to UTC (Coordinated Universal Time), so midnight EST will be 5 hours earlier in the dateTime column (the previous day, at 7pm).

To override the UTC timezone, specify a valid timezone in the tz argument. Default is ““, which will keep the dateTime column in UTC. Other valid timezones are:

America/New_York
America/Chicago
America/Denver
America/Los_Angeles
America/Anchorage
America/Honolulu
America/Jamaica
America/Managua
America/Phoenix
America/Metlakatla

Data are retrieved from https://waterservices.usgs.gov/rest/IV-Test-Tool.html. There are occasions where NWIS values are not reported as numbers, instead a common example is “Ice”. Any value that cannot be converted to a number will be reported as NA in this package. Site information and measured parameter information is attached to the data frame as attributes. This is discussed further in metadata section.

1.5 Water Quality Data

To get USGS water quality data from water samples collected at the streamgage or other monitoring site (as distinct from unit values collected through some type of automatic monitor) we can use the function readNWISqw, with the input arguments: siteNumber, parameterCd, startDate, and endDate. Additionally, the argument expanded is a logical input that allows the user to choose between a simple return of datetimes/qualifier/values (expanded=FALSE), or a more complete and verbose output (expanded=TRUE). expanded = TRUE includes such columns as remark codes, value qualifying text, and detection level for each parameter code. There also includes an argument “reshape”, that converts the expanded dataset to a “wide” format (each requested parameter code gets individual columns). The defaults are expanded=TRUE, and reshape=FALSE.

# Dissolved Nitrate parameter codes:
parameterCd <- c("00618","71851")
startDate <- "1985-10-01"
endDate <- "2012-09-30"

dfLong <- readNWISqw(siteNumber, parameterCd, 
      startDate, endDate)

# Or the wide return:
dfWide <- readNWISqw(siteNumber, parameterCd,
      startDate, endDate, reshape=TRUE)

Site information and measured parameter information is attached to the data frame as attributes. This is discussed further in the metadata section. Additional metadata, such as information about the column names can be found by using the comment function, also described in the metadata section.

comment(dfLong)

1.6 Groundwater Level Data

Groundwater level measurements can be obtained with the readNWISgwl function. Information on the returned data can be found with the comment function, and attached attributes as described in the metadata section.

siteNumber <- "434400121275801"
groundWater <- readNWISgwl(siteNumber)

1.7 Peak Flow Data

Peak flow data are instantaneous discharge or stage data that record the maximum values of these variables during a flood event. They include the annual peak flood event but can also include records of other peaks that are lower than the annual maximum. Peak discharge measurements can be obtained with the readNWISpeak function. Information on the returned data can be found with the comment function and attached attributes as described in the metadata section.

siteNumber <- '01594440'
peakData <- readNWISpeak(siteNumber)

1.8 Rating Curve Data

Rating curves are the calibration curves that are used to convert measurements of stage to discharge. Because of changing hydrologic conditions these rating curves change over time. Information on the returned data can be found with the comment function and attached attributes as described in the metadata section.

Rating curves can be obtained with the readNWISrating function.

ratingData <- readNWISrating(siteNumber, "base")
attr(ratingData, "RATING")

1.9 Surface-Water Measurement Data

These data are the discrete measurements of discharge that are made for the purpose of developing or revising the rating curve. Information on the returned data can be found with the comment function and attached attributes as described in the metadata section.

Surface-water measurement data can be obtained with the readNWISmeas function.

surfaceData <- readNWISmeas(siteNumber)

1.10 Water Use Data

Retrieves water use data from USGS Water Use Data for the Nation. See https://waterdata.usgs.gov/nwis/wu for more information. All available use categories for the supplied arguments are retrieved.

allegheny <- readNWISuse(stateCd = "Pennsylvania",
                         countyCd = "Allegheny")


national <- readNWISuse(stateCd = NULL, 
                        countyCd = NULL, 
                        transform = TRUE)

1.11 Statistics Data

Retrieves site statistics from the USGS Statistics Web Service beta.

discharge_stats <- readNWISstat(siteNumbers=c("02319394"),
                   parameterCd=c("00060"),
                   statReportType="annual") 

3.1 NWIS

sites <- whatNWISsites(bBox=c(-83.0,36.5,-81.0,38.5), 
                      parameterCd=c("00010","00060"),
                      hasDataTypeCd="dv")

dischargeWI <- readNWISdata(service="dv",
                           stateCd="WI",
                           parameterCd="00060",
                           drainAreaMin="50",
                           statCd="00003")

siteInfo <- attr(dischargeWI, "siteInfo")

3.2 WQP

Just as with NWIS, the Water Quality Portal (WQP) offers a variety of ways to search for sites and request data. The possible Web service arguments for WQP site searches is found here.

sitesNJ <- whatWQPsites(statecode="US:34",
                       characteristicName="Chloride")

dataPH <- readWQPdata(statecode="US:55", 
                 characteristicName="pH")

type <- "Stream"
sites <- whatWQPdata(countycode="US:55:025",siteType=type)

site <- whatWQPsamples(siteid="USGS-01594440")

type <- "Stream"
sites <- whatWQPmetrics(countycode="US:55:025",siteType=type)

5.1 New to R?

If you are new to R, you will need to first install the latest version of R, which can be found [here] (www.R-project.org).

At any time, you can get information about any function in R by typing a question mark before the functions name. This will open a file (in RStudio, in the Help window) that describes the function, the required arguments, and provides working examples. This will open a help file similar to the image below. To see the raw code for a particular code, type the name of the function, without parentheses.

?readNWISpCode

A simple R help file

Additionally, many R packages have vignette files attached (such as this paper). To view the vignette:

vignette(topic = "Introduction", package = "dataRetrieval")