This study quantifies downstream responses to low head dams in the Hill Country region of Texas.  These responses fall into general abiotic and biotic categories.  Abiotic shifts are expected to occur in total suspended solids, particulate organic matter, water velocity, pH, and specific conductance.  Biotic responses may include changes in the macroinvertebrate community (abundance, richness, presence) and disruption of drift.  Preliminary results from several sites will be presented.  Research on such structures has not occurred in this area and will aid in the understanding of general trends associated with the scaling of effects of large to small dams.  These observations will additionally expand the field of low head dam research into subtropical regions.