A review of autonomous and low cost sensor systems for surface water quality monitoring with implications for local decision making

Preserving water quality has become a critical priority due to the increasing pressure on water resources from population growth, production activities and climate change. This article reviews recent studies on water quality monitoring in lakes, rivers and reservoirs, with a focus on lessons relevant to local decision-making. Using a structured literature review approach, we synthesised and interpreted research on water quality monitoring systems used in aquatic ecosystems affected by eutrophication and turbidity. Particular attention was given to turbidity sensors and autonomous monitoring approaches. The findings show that traditional manual quality measurements continue to coexist with autonomous monitoring systems, each contributing different strengths to water quality assessment. However, studies on low-cost sensors and permanent autonomous measurement systems remain limited, likely because of other research priorities. The limited number of published studies suggests either that these systems remain uncommon in practice or that their use is insufficiently documented. Current monitoring efforts largely rely on field manual sampling carried out by specialised technical personnel employed in state services or research centres. Looking ahead, it appears promising to complement current methods by increasingly integrating low-cost autonomous sensor networks and expanding opportunities for citizen participation. Such developments could support the creation of real-time information systems that facilitate local decision-making.