NashMod :   a conceptual hydrologic rainfall-runoff (stream flow) simulation model with a cascade of linear reservoirs
Totally free download of software

The NashMod 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 a cascade of linear retention reservoirs.
Modelling with NashMod gives the opportunity of calculating the streamflow resulting from rainfall on the watershed (catchmnent) and of flood forecasting.

The number of reservoirs and their reaction (response) factor can be determined from recorded rainfall-runoff data. The program uses a large number of reservoirs and reaction
      More details are given in the program itself.

The program starts giving clicking on NasMod.Exe.
More information is given in the program itself.

This program is similar to RainOff but RainOff uses a non-linear reservoir instead of a series of linear reservoirs.

A program with 2 reservoirs having different reaction factors was also made. Here, the first reservoir represents the surface flow and the second the stream flow. It can be made available on request.


Go to:

& models

General articles
& manuals

(in Spanish,
en Español)

reports & cases

reports & cases

& answers


Input tabsheet of NashMod

input Nash model

The input shows rainfall, storage characteristics and evaporation (as escape rate) from which the effective recharge is computed. It also shows the measured discharge or runoff with which the reservoir coefficient can be calibrated.
Output tabsheet of NashMod

output Nash model

The ouput shows the hydrograph of runoff or discharge (streamflow) and the goodness of fit of the model outcome to the measured data.