diff --git a/vignettes/dataRetrieval.Rnw b/vignettes/dataRetrieval.Rnw
index 72dab59a7f668c87068799d663b8f00538743104..0e5c361355590dd43d6b4c3a08d251f7acea0b23 100644
--- a/vignettes/dataRetrieval.Rnw
+++ b/vignettes/dataRetrieval.Rnw
@@ -545,7 +545,7 @@ url_uv <- constructNWISURL(siteNumber,"00060",startDate,endDate,'uv')
 \section{Water Quality Portal Web Retrievals}
 \label{sec:usgsSTORET}
 %------------------------------------------------------------
-There are additional water quality data sets available from the Water Quality Data Portal (\url{http://www.waterqualitydata.us/}).  These data sets can be housed in either the STORET (data from EPA), NWIS database (data from USGS), STEWARDS database (USDA), and additional databases are slated to be included.  Because only USGS uses parameter codes, a \texttt{"}characteristic name\texttt{"} must be supplied.  The \texttt{getWQPqwData} function can take either a USGS parameter code, or a more general cahracteristic name in the parameterCd input argument. The Water Quality Data Portal includes data discovery tools and information on characteristic names. The following example retrieves specific conductance from a DNR site in Wisconsin. 
+There are additional water quality data sets available from the Water Quality Data Portal (\url{http://www.waterqualitydata.us/}).  These data sets can be housed in either the STORET database (data from EPA), NWIS database (data from USGS), STEWARDS database (data from USDA), and additional databases are slated to be included.  Because only USGS uses parameter codes, a \texttt{"}characteristic name\texttt{"} must be supplied.  The \texttt{getWQPqwData} function can take either a USGS parameter code, or a more general characteristic name in the parameterCd input argument. The Water Quality Data Portal includes data discovery tools and information on characteristic names. The following example retrieves specific conductance from a DNR site in Wisconsin. 
 
 
 <<label=getQWData, echo=TRUE, eval=FALSE>>=
@@ -553,6 +553,7 @@ specificCond <- getWQPqwData('WIDNR_WQX-10032762',
                 'Specific conductance','2011-05-01','2011-09-30')
 @
 
+Guidance for finding characteristic names can be found at: \url{http://www.waterqualitydata.us/webservices_documentation.jsp}.
 
 \FloatBarrier