This study evaluates the effectiveness of a newly developed educational framework for enhancing scientific literacy in rural high school classrooms. The Confluence Approach (TCA) is a curriculum aligned to the Next Generation Science Standards (NGSS) that utilizes a combination of project-based learning (PrBL) and place-based education (PlBE). TCA educational activities take place in students' local watersheds where they interact with local partners and gain experience carrying out science and engineering practices focused on water quality, water quantity, and water use in real world settings. In 2014-15, before and after participation in a year-long TCA program, researchers administered attitudinal surveys to understand the program's impact on two important aspects of scientific literacy: students' perceptions of science as important to society and personal decision-making, and student ability to carry out scientific practices. Qualitative and quantitative survey results were analyzed using a mixed methods approach, where qualitative data were coded using both a priori and grounded theories and quantitative data were analyzed with exploratory factor analysis and Mann-Whitney-Wilcoxon tests to compare pre- and post-survey responses. Results show that completion of a TCA program positively changed students' perceptions of the importance of science, both locally and globally, and it increased their confidence engaging in scientific practices. Recommendations from this work include utilizing local contextual factors as frequently as possible to enhance curriculum relevance for students and to use PrBL curriculum elements to elevate student confidence with scientific practices.