1.   Purpose and objectives

     To provide a user-friendly interactive computer package to: 1) create and maintain a station/basin hydrometeorological data base for the BSTOR package; 2) perform independent estimates of areal evapotranspiration for use as input to the water balance equation; 3) analyze the variations of basin storage and water balance for the detection of possible trends and/or data deficiencies.

2.   Description

     The BSTOR package allows the user to: create a station/basin data file system for analysis; modify data sets so as to add, delete or modify all stored information; tabulate and plot data sets for preliminary analysis; and perform independent estimates of areal evapotranspiration based on 
Morton's complementary relationship model which provides three computational options: 1) areal evapotranspiration; 2) wet surface evaporation; and 3) lake evaporation.

     The basin data files are created from data files of stations using user specified station weights. The time period for computations is monthly. The water balance analysis may be performed on the basis of a calendar year or other user specified cycles (e.g. September to August).

     The water balance and basin storage computations provide the user with an interactive facility to: 1) compute the station's rain and snowmelt using the total precipitation and the snow on the ground on the last day of the month; 2) create basin data files of total precipitation, rain and snowmelt, and evapotranspiration; and 3) compute basin water balance and storage content using previously created basin data files.

3.   Input

     Station data files include monthly time series of mean air temperature, dew point temperature, sunshine duration, total precipitation, total snowfall, snow on ground on the last day of month, discharge, computed rain and snowmelt, and computed station evapotranspiration.

     Basin data files are created from station data files. They include: discharge, evapotranspiration, rain and snowmelt, total precipitation, and computed basin storage content.

4.   Output

     A tabulation of input and/or computed data series; the computed net radiation, potential and areal evapotranspiration, wet surface evaporation, and lake evaporation; the components of the water balance averaged over a user-specified time period; the mass curves of the water balance components; a time series of the water balance components including storage content; and a concurrent basin storage plot.

5.   Operational requirements and restrictions

     The current version of BSTOR software was written in Fortran 77 to run under DOS 3.1 on IBM-type microcomputers with a math coprocessor. However, it can also be used on computers running Windows 95 and 98. 

     BSTOR was designed to be user friendly and interactive, thus no knowledge of programming is required to operate the package. Interpretation of results should be performed by analysts having knowledge of the assumptions and limitations of the approaches and mathematical treatment. User's knowledge of the drainage basin and the station characteristics are indispensable for the proper analysis and interpretation of the results.

6.   Form of presentation

     Diskettes with executable program and a sample data set. The program and user manual are in English.

7.   Operational experience

     BSTOR has been applied to many drainage basins in Canada and is currently used by various government agencies and research institutes.

8.   Originator and technical support

     Atmospheric Environment Service, Environment Canada.

9.   Availability

     From the HOMS National Reference Centre for Canada.

10.  Conditions on use

     The diskettes and user manual are available free of charge.