RivDIS - RivDIS contains monthly discharge measurements for 1018 stations 
located throughout the world. The period of record varies widely from station 
to station with a mean of 21.5 years. The data were digitized from published 
UNESCO river archives by Charles Vorosmarty, Balazs Fekete, and B. A. Tucker of 
the Complex Systems Research Center (CSRC) at the University of New Hampshire.
Additional background information on these data is available by accessing the 
associated guide document or the RivDIS page maintained by the CSRC. 

The overall characteristics and availability of this data collection are summarized below. 

    Spatial: gauging stations located on major rivers throughout the world 
    Temporal: station-specific, ranging from 1807 to 1991 
    Data Themes: river discharge 
    Project Status: final; The data is available as one global file 
                    or as individual station files.

RivDIS data:
  RIVDIS.DAT  
	Monthly average discharge in cubic meters/sec 262791 records
  STATION.DAT
	Companion File 
  STATIONS
        A directory tree containing data and information about
        individual stations, organized by country and station.
    TEXT
        A subdirectory tree containing data for individual stations 
        and HTML files summarizing the corresponding data.  The
        HTML files (viewable using a web browser) display plots
        stored in the IMG subdirectory.
    IMG
        A subdirectory containing GIF files of plots.
	
About the plots:
  For individual stations, there may be gaps during
which no data were collected.  Gaps are
ignored (rather than being counted as zero flow)
in deriving quantities to be plotted.  There are
3 plots for each station, as described below.

"Mean Discharge Regime"
  Derived by summing all available discharge
measurements for a particular month and dividing 
by the number of measurements.

"Flow Duration Curve"
  Flow duration is defined in "Applied Hydrogeology"
by C.W. Fetter, Jr. as the probability that a
given flow will be equaled or exceeded.
The probabilities are obtained by simply counting
the number of equal or higher measurements for each
measured flow rate.  Dividing by the total number
of measurements gives the flow duration as a
fraction.  The fractions are then sorted by 
discharge value and converted to percent.
The resulting curve always falls monotonically 
with increasing flow rate.

"Monthly Discharge"
  The available discharge data are plotted for the 
period 1960 to 1990.  Flow duration levels labelled
10%, 50%, and 90% are deduced from the Flow Duration
Curve and include all measurements, not just those
during the interval 1960 to 1990.  These levels 
correspond to the closest measured value 
(no interpolation is done) so they are imprecise 
when the number of data points is small.


KEYWORDS:
river, discharge, water, monthly, measurements, average, global, station