a conceptual rainfall-runoff simulation model with
a nonlinear reservoir
Totally free download of software
The RainOff computer program, or simulation model,
calculates runoff from rainfall on watersheds
(hydrologic catchment areas) whose extension is
limited by the condition that the rainfall can be
assumed evenly distributed over the area.
The program can be freely downloaded, it is free
shareware in the public domain.
The rainfall is converted into recharge by routing
through a retention reservoir from which water
escapes depending on predetermined characteristcs
as storage capacity, initial storage and maximum
rate of escape (representing evaporation or
drainage). This first reservoir gives the recharge
(rainfall excess) as overflow.
The recharge is routed through a second,
non-linear, reservoir with a reaction factor whose
on the storage level. Thus, the conversion
(transformation) of rain into runoff (surface
drainage) and flooding is produced.
Modelling with RainOff gives the opportunity of
predicting the hydrology of the watershed
(catchmnent) and of flood forecasting.
The reaction (response) factor can be determined
from recorded rainfall-runoff data. The program
uses various reservoir functions and selects the
optimal function. Alternatively, it is possible
to introduce the reservoir function, together
with rainfall data, and the program will
calculate the runoff.
On 12 December 2010 an extra graph was provided
for the recorded rainfall-runoff statistics and
trends, thanks to a suggestion by Mr. Juan
On 27 August 2012 the program was updated to
include a quadratic reservoir function and on
1 december 2012 a Help function and an
observed-calculated graph was added.
More details are given in the program itself.
The program starts giving clicking on
More information is given in the program itself.
A lecture note ("Data Analysis") on drainage
research with examples of RainOff applications is
found on the articles
An example of the application of the Curve Number
Method for the design of a surface drainage
system for sugar cane plantations in a humid
tropical coastal area can be found in a chapter
("Agricultural Drainage Criteria"), also on the
reports & cases
reports & cases
Introduction screen of RainOff program
Example of RainOff application