One of the keys to science and environmental literacy is systems thinking. Learning how to think about the interactions between systems, the far-reaching effects of a system, and the dynamic nature of systems are all critical outcomes of science learning. However, students need support to develop systems thinking skills in undergraduate geoscience classrooms. While systems thinking-focused instruction has the potential to benefit student learning, gaps exist in our understanding of the links between undergraduate students' systems thinking about Earth systems, particularly their metacognitive evaluation of systems thinking. To address this need, we have designed, implemented, refined, and studied an introductory-level, interdisciplinary course focused on coupled human-water, or socio-hydrologic, systems. Data for this study comes from three consecutive iterations of the course and involves student models and explanations for a socio-hydrologic issue (n=163). To analyze this data, we applied an operationalization rubric to the written responses and counted themed features of the drawn models. Preliminary analyses of the written explanations reveal statistically-significant differences between underlying categories of systems thinking, F (3, 172)=2.66, p<0.05. Students were best able to operationalize their systems thinking about implementation challenges (M=2.07 SD=0.97) as compared to stakeholder awareness (M=1.20, SD=0.79), t(43)=-6.33, p<0.05, and unintended consequences (M=1.86, SD=1.05), t(43)=-4.14, p<0.05. Student-generated systems thinking models focused most strongly on system components (M=11.44, SD=4.09) as compared to related processes or mechanisms F(2, 132)=3.06, p<0.05. This indicates that students were most likely to include components in their models, but also included system processes and mechanisms. These findings have implications for supporting systems thinking in undergraduate geoscience classrooms, as well as insight into links between these two skills.