QNAPLT is a plotting routine that allows the user to view daily historical data (residing in the HYDROMET archives database) under various plotting formats. The unique feature of QNAPLT is it allows the user to plot cumulative daily data and average cumulative daily data in addition to the normal plotting of the daily values themselves under the regular plotting routines. Cumulative daily data are accumulated over a specified period as defined by the user and averaged cumulative daily data are computed for a specified period of years as requested by the user. Plotting cumulative data is beneficial when comparing stream flow or reservoir inflow volumes among different years or to compare the current year values with the average for a selected period of years.
The Bureau of Reclamation HYDROMET archives database stores data in a WATER YEAR format. A given water year begins on October 1 of the previous year and ends on September 30 of the given year. For example, water year 1997 includes data from October 1, 1996 through September 30, 1997. Keep this in mind when requesting data.
In the beginning and ending, month and day fields, enter the time period you wish to display. The default is a standard water year, October 1 through September 30. The dates must fall within a single water year.
In the next set of columns you can request up to 6 different data sets as long as these do not include more than any two different units of measurement. Under the station heading, input the station code for the station of interest. A complete listing of station codes can be found by CLICKING HERE.
Tab to the next field or move the cursor. Do not hit the enter key as this will cause the program to malfunction and no data will be retrieved. Under the parameter heading, input the parameter code of interest. A listing of all available parameter codes for all stations is available by CLICKING HERE.
Under the year heading, type in the desired 4-digit water year.
Under the annual cumulative heading, you may request cumulative values by clicking the checkbox. Leaving this box unchecked will result in no accumulation of data. Parameters whose values can be accumulated include: daily mean air temperature (MM), daily minimum air temperature (MN), daily maximum air temperature (MX), daily precipitation (PP), daily mean computed reservoir inflow (IN), and daily mean discharge (QD).
You may request average values for a specified period of years by clicking the checkbox under the historical average
heading and entering the number of years for which the average is to be calculated under the years-to-average heading.
Leaving the checkbox unchecked will result in no averaging of data.
Note: The cumulative and average options may be used simultaneously or otherwise.
Below the table for the six data sets is a data entry field for specifying a base temperature if a plot of cumulative temperatures has been requested. As an example, entering a value of 32 degrees F. will result in the accumulation of all the differences between each daily temperature and 32 degrees F. This may be helpful in correlating snowmelt runoff to the accumulation of degree days above freezing.
The plot scale limit fields refer to the vertical scales on either side of the graph and provide a means to override the computer-generated y axis scaling of the plot. By the user ignoring these fields, the plot will automatically scale to fit the data requested. Normally the user need not make entries in these fields.
Once all the entries have been made into the appropriate fields, click the submit button and the data will be plotted.
Last Updated: January 11, 2011