A local mode approach by V. Buch was used to calculate anharmonic IR spectra of alkali cation microhydration clusters (M⁺(H₂O)_n with M = Na, K, Cs and 4 ≤ n ≤ 22) in the vibrational OH stretch region to investigate the possibility of obtaining structural information from experimental IR spectra, in conjunction with theoretical data. The cluster structures were globally optimized within the common TIP4P/OPLS potential using a specialized version of our genetic algorithm. Having a large number of global and local minima structures at hand, it was possible to provide an ample range of spectral data for the elucidation of trends in peak patterns with respect to these cluster structures. For some structural features, prominent peak patterns were found, thus allowing experimentalists to better interpret their spectral data and to extract structural information directly. Other patterns however are too congested for interpretation without theoretical support. Thus combining experiment with theory will provide a method of acquiring structural information from the experiment.