*Result*: A comprehensive approach to conducting multi-criteria sensitivity analysis of computationally expensive multidimensional hydrodynamic-ecology models (MHEs).

*The reservoir-simulating multidimensional hydrodynamic-ecology (MHE) models are too complex and computationally expensive, rendering modelers unable to conduct suitable sensitivity analysis (SA). The Morris, Fourier Amplitudes Sensitivity Test (FAST), and Extended Fourier Amplitude Sensitivity Test (eFAST) SA techniques and the newly built parallelization software were utilized in randomized factorial experiments on a test-MHE – AEM3D model to ascertain an affordable and appropriate SA technique. A comprehensive multi-criteria SA was performed, incorporating 49 objective criteria, alongside experiments assessing run length and model resolution impacts. The parallelization tool reduced model runtime by 3000%, as the Morris method accurately identified the most significant parameters, which the standard techniques FAST and eFAST also identified, albeit with significantly fewer iterations. The study concludes that parallelization, the Morris technique, coarse resolution, shorter run-length, and multi-criteria SA combined with the newly proposed rank frequency method can facilitate cost-effective and reliable SA utilizing office computers. The approach enables water agencies to quickly assess climate-change impacts and develop adaptation strategies. [ABSTRACT FROM AUTHOR]*