The Southern Nevada Water Authority (SNWA) plans to pump deep aquifers in isolated basins of eastern Nevada.  Springs in these pluvial basins are at risk of drying if the water table is depressed. While SNWA will mitigate spring desiccation, it is unknown which invertebrate taxa are capable of recolonizing, nor how unique populations within or between basins are.  We hypothesize that aquatic invertebrates with low dispersal ability will tend to be genetically unique between basins while invertebrates with high dispersal capabilities will be less unique.  Five springs were qualitatively sampled from each of six basins.  Two of the basins will be directly impacted by the pumping project.  A mitochondrial gene, Cytochrome c oxidase subunit I (COI), and a nuclear gene, ribosomal subunit 28S, were sequenced from Hyalella azteca.  Parsimony and Bayesian phylogenies showed that neither populations within basins nor populations between basins showed monophyly.  Many individual spring populations have undergone cryptic speciation.  Genetic divergences averaged 6.9% within and 13.2% between populations.  Evidence supports ancient lineages within springs as well as some recent (Pleistocene) dispersal between basins.  These results are being compared to COI and 16S genes from Callibaetis spp, which should have intermediate dispersal abilities.