Evaluation of Distributed Sensor Configurations for Rainwater Harvesting Monitoring Systems

Abstract Increasing risk of water scarcity in Mexico City has led to expansion of the practice of rainwater harvesting (RWH). However, it remains difficult to assess the benefits of the increased number of installations due to uncertainty in new users’ propsensity towards long-term adoption of these systems. This research proposes the use of sensors to aid in the study of RWH system adoption. A challenge that has presented itself in the instrumentation of RWH systems is the cost-effective collection of data from multiple sources that are physically separate at a common ‘gateway’ node for transmission. This study presents and evaluates three potential approaches to solving this problem: (1) the use of wires to connect sensors to the gateway node, (2) the use of LoRa-enabled wireless nodes configured in a self-organizing mesh network, and (3) LoRa-enabled nodes configured in a star network topology. An analysis of the cost of each configuration was performed, indicating that the wired system ($330.9 USD) was notably cheaper than the wireless options (> $425.3 USD) due to the expense of multiple LoRa radios. However, the potential cost saving advantage of LoRa mesh nodes sharing a network between households allows for the possibility of a per-household deployment cost even cheaper than the wired system. A qualitative analysis also explores the substantial limitations of the wired system due to challenges in its installation.