IHACRES Rainfall-Runoff Model: A Review Paper

The IHACRES model is being applied in a regionalization approach to develop streamflow predictions. The IHACRES rainfall-runoff model uses a non-linear loss module to calculate the effective rainfall and a linear routing module to convert effective rainfall into stream flow. A new version of the non-linear module, developed to aid in estimating flows in ungauged basins and for applications where time series estimates of actual evapotranspiration are required. The new module has only 3 parameters and has significantly less correlation between the parameters. Model used one of these regression relationships to represent possible effects of declining forest cover on streamflow, but did not obtain regional models for the parameters of the routing model of IHACRES. Future research should focus on (1) increasing the quality of rainfall estimates as an important way to potentially improve simulation performance; (2) developing joint probability distributions over the full set of IHACRES model parameters to improve estimates of predictive uncertainty; and (3) developing estimates of actual forest cover trends to obtain more useful predictions of future trends in streamflow.