An assessment of volunteer-collected water data in Montana: how much data is there and what questions can it answer?

Abstract

Citizen science plays an increasingly important role in environmental data collection, and one of the most prominent forms of citizen science in the United States is volunteer water quality monitoring. However, the outcomes of volunteer water quality monitoring projects are rarely compiled comprehensively. In Montana, no synthesis of the extent of volunteer-collected water quality data exists, and little is known about how well volunteer data is poised to address the goals and objectives of the groups collecting it. Therefore, this study develops and applies a mixed‑methods framework to evaluate whether volunteer water quality monitoring programs in Montana are collecting data sufficient to achieve their monitoring goals and objectives articulated in monitoring groups’ Sampling Analysis Plans. Leveraging connections with volunteer water quality practitioners, I identified 43 independent volunteer monitoring projects across Montana. Project goals and objectives were qualitatively coded using deductive, inductive, and thematic approaches, then merged with project‑level National Water Quality Portal datasets by parameter type. Project‑goal combinations were evaluated using metrics describing monitoring duration, spatial extent, analyte diversity, and sampling frequency to assess how well dataset structures aligned with their stated monitoring intentions. Results show that volunteer monitoring has expanded statewide since 2001, with sampling concentrated in western Montana. Baseline and trend analysis goals are the most common across projects, while source assessment, effectiveness monitoring, and education goals are less frequent. Most groups sample primarily during summer baseflows, resulting in limited coverage during hydrologically important runoff periods. Projects with long‑term datasets or broad spatial and temporal coverageare comparatively well positioned to address their stated goals, while projects seeking to evaluate pollutant sources or restoration effectiveness often lack the temporal resolution required. This study demonstrates that assessing volunteer‑collected data against monitoring intent provides a clearer understanding of dataset adequacy and highlights opportunities to strengthen volunteer monitoring designs through expanded seasonal sampling, more intentional articulation of education goals, and integration of additional monitoring metrics.