Continuous records of environmental parameters are an important component of water resources management planning. Water levels in streams often increase within minutes and hours of a rain event and demand frequent and, thus, automated recording of parameters. Yet, conventional systems for the automatic measurement and recording of water levels and other environmental parameters often are expensive. This limits the number of automated monitoring stations that can be installed in a watershed or region. In developing countries, monitoring stations often are scarce, and continuous streamflow data are limited. This limitation makes planning for adaptation to floods and droughts challenging for communities.
Above image: Water shortages are common during the dry season in Guanacaste, Costa Rica.
Open-Source Opportunities
Recent advancements in open-source technology provide opportunities for the development of low-cost data loggers. Like open-source software, open-source hardware provides development source codes and hardware schematics free of charge. This encourages further development, cooperation and exchange within the open-source community.
The Arduino Project provides open-source hardware in the form of microelectronic platforms and schematics that can be modified for a number of applications. The microelectronics board is programmed using an open-source language. A variety of components, such as an SD card reader for data recording or attachments for environmental sensors, can be added to the Arduino board.
The sensor is installed in a PVC tube that extends into the river to measure water depth and is connected by cable to the data logger.
The Logger
Researchers at the University of British Columbia in Vancouver, Canada, used these features to turn the Arduino board into an environmental data logger, the Ecohydro Logger. Water sensors, such as Decagon Devices CTD sensors, can be attached to the logger. Their signal is read via a serial digital interface and recorded to an SD card. This allows for the automated monitoring of environmental parameters, such as stream water depth, water temperature and electrical conductivity.
The data loggers were designed to work in remote locations, such as in streams in the middle of the forest, far away from electricity. Solar panels were used for power generation and connected to recharge batteries that in turn power the data logger. We also implemented power-saving modules to guarantee power supply during overcast periods. The logger was programmed to record data every 10 minutes and to power down between measurements for power conservation.
Testing & Monitoring in Costa Rica
The University of British Columbia scientists implemented the data logger for hydrologic monitoring in the tropics of northwestern Costa Rica. This region is characterized by distinctive wet and dry seasons. Communities often are faced with high stream flows during the wet season and water shortages during the dry season. The dry season is especially challenging, as water becomes contested between agriculture, households and tourism. While a few monthly measurements of stream flow exist, continuous monitoring is limited in the region.
In June 2014, the monitoring stations were installed within the Potrero and Caimital watersheds close to the town of Nicoya in Guanacaste, Costa Rica. After overcoming initial challenges, the data loggers have been working well despite the high humidity and strong rainfall events of the tropical wet seasons. The sensors were installed within PVC tubes and tightened along roots and trees of riverbanks to withstand the force of storm flows. To ensure the safety of the equipment, monitoring stations were installed on private properties adjacent to rivers.
Monitoring in the midst of the tropical forest, the logger records water levels from the nearby Rio Caimital.
Community Service
An essential part of the project’s success was cooperation with the local community and water agencies. The research was part of FuturAgua, a larger inter-disciplinary project established through the Belmont Forum. The project involved local stakeholders and encouraged exchange between the community and researchers. These connections were fundamental for basing the research within the needs of the community, as well as for identifying property owners for the installation of equipment.
Many property owners developed stewardship over the monitoring stations that were installed in close proximity to their homes. Furthermore, as local people often experience water shortages, whether from household water taps running low during the dry season or encountering water shortages as farmers, they were generally interested in supporting the monitoring of local water resources. The monitoring results will be used to support a hydrological model and evaluate different strategies for community adaptation to climate change and changing water use.
Low-cost and open-source data loggers show great potential for automated and continuous monitoring of environmental variables, and can provide powerful means for extending monitoring into data-scarce regions. The adaptable and open-source nature of the system may allow integration into community-based research and citizen science.
