This research study, grounded in experiential learning theory, utilized a draw-and-explain assessment to measure change in secondary students' knowledge before and after an experiential field trip. Our results indicated that the secondary students (aged 15-18 years) had pre-existing knowledge of the local delta area that included both abiotic and biotic factors. Prior to the field trip students drew generic and isolated configurations of land and water features. The change in scores from pre- to post-visit drawings indicated that the experiential field trip did cause an overall statistically significant change in students' knowledge of the local delta environment. Our findings denote the importance of outdoor field experiences and calls attention to the need for collaboration between informal and formal educators. Based on the findings of this study, an experiential learning approach could provide an effective model for informal program design and formal classroom activities related to field experiences. The researchers make suggestions for formal and informal educators that reflect the findings and relate to the experiential learning cycle.