Real-time Groundwater Monitoring via Internet of Things Platform
Summary
In southwestern Nova Scotia, most residents rely on domestic wells for their water supply, around 30% of which are shallow dug wells. There is a notable lack of up-to-date information on groundwater levels and many existing wells are not able to provide regular updates on aquifer water levels. The Nova Scotia Geological Survey developed a real-time, shallow groundwater level monitoring network for dug wells to help fill data gaps.
The solution is cost-effective as it relies on volunteers and their wells, along with a Wifi or cellular network connection. The water level meters transmit water level data in real-time via an Internet of things device, and the system costs approximately USD 150 to 225 for wifi and cellular models, respectively. There are a few challenges associated with the model, however, there are compelling solutions that address them, and the benefits of citizen science are worth exploring in further depth.
In southwestern Nova Scotia, most residents rely on domestic wells for their water supply, approximately 30% of which are shallow dug wells of less than 8m in depth that are vulnerable to water table declines (Drage & Kennedy, 2020). During droughts, similar to the 2016 drought which came in as part of the driest summer in 137 years, there is a need for emergency management staff and the public to have up-to-date information on groundwater levels. However, the existing provincial groundwater observation well network, which consists of 40 drilled wells spread out across the province, was not equipped with real-time monitoring equipment and, therefore, not able to provide regular updates on aquifer water levels (Drage & Kennedy, 2020).
Intervention
In response to the need to obtain real-time monitoring data, the Nova Scotia Geological Survey developed a real-time, shallow groundwater level monitoring network for dug wells so that up-to-date data would be available to help manage future droughts (Prentiss, 2018; Drage & Kennedy, 2020). The data from the network is also used to validate a provincial groundwater drought impact prediction model (Drage & Kennedy, 2020). Moreover, the challenge of obtaining regular measurements by relying on citizen science is overcome by automating the data collection process, however, the project did require volunteers who had dug wells located near their homes. Volunteers were recruited for the project by word-of-mouth, newsletter blurbs and radio and TV interviews (Drage & Kennedy, 2020).
To keep costs low, the water level meter developed for the project was based on a simple, do-it-yourself meter for measuring water levels in a household water storage tank and deployed in a network of domestic wells provided by community volunteers. The meter has four main components: an ultrasonic sensor to measure the depth to groundwater level , an Internet of Things (IoT) device to control the sensor and transmit the water level data to the Internet to be stored and viewed, a battery pack and an antenna (Drage & Kennedy, 2020). All pieces of equipment are readily available from online retailers (Drage & Kennedy, 2020). At the time of the study, the meters were programmed to measure and report water levels once a day, although any monitoring frequency can be used (Drage & Kennedy, 2020).
The water level meters transmit water level data in real-time to the Internet using the private wifi network at each volunteer's house, which requires the well to be located within approximately 50m to the modem. In cases where the wifi signal is too weak, an external antenna can be attached to the water meter and/or a wifi range extender can be installed in the volunteer's home, costing an additional USD 25 and USD 30, respectively (Drage & Kennedy, 2020). Real-time data transmission costs are also kept low by the use of, in most cases, the volunteers' home wifi. As an alternative, a cellular version of the water meter has also been developed for situations where no wifi network is available, though it is more expensive to build and operate compared to the wifi version, with parts costing approximately USD 225 (compared to USD 150 for the wifi version) and an additional USD 3/month for the data plan (Drage & Kennedy, 2020). Similar commercially available meters cost USD 2,500 each.
Challenges
While the meters have generally performed well in the field, there are a few challenges that have been identified. First, the meters require a wifi/cellular connection, which could be challenging for scalability in low-resource contexts. Similarly, the reliance on a wifi network means that any changes to said network (i.e., network name or password change), means the water meters can no longer connect to the Internet and therefore requires a field visit to update the meter (Drage & Kennedy, 2020). Second, if the meters face connection issues, data is not transmitted and is permanently lost due to no data logger (Drage & Kennedy, 2020). While a data logger could be added to the meter, this would increase the associated costs. The third and fourth noted challenges relate to the environment in which the meters are implemented. The third challenge is inaccurate water level measurements in dug wells constructed with rock walls. While new dug wells are generally constructed with casing made of precast concrete rings, older wells with rock walls likely cause the ultrasonic signal to reflect off the walls, though this can be remedied by installing a PVC pipe 75mm in diameter into which the meter can be inserted (Drage & Kennedy, 2020). Finally, the study found that frost formation on the ultrasonic sensor caused incorrect water level measurements (i.e., depth to water was reported as 0). This problem can be fixed by installing water meters 1-2m below ground level, however, this challenge would likely not be seen in warmer climates (Drage & Kennedy, 2020).
Outcomes
The network has been successful in monitoring groundwater levels in dug wells and real-time meters (Drage & Kennedy, 2020). Data shows a typical annual pattern observed in shallow aquifers across the province, with higher groundwater levels in the winter and spring (January to May), followed by a summer groundwater recession (June to August) when precipitation and recharge rates are low, followed by rising water levels in the fall (September to November) when rainfall returns (Drage & Kennedy, 2020). Moreover, the recruitment program was successful in attracting more volunteers than could be accommodated. The first wells were added to the network in 2017 and additional wells were added in 2018 and 2019. Ten wells use a wifi version of the meter and one uses a cellular version (Drage & Kennedy, 2020). Wells are also visited once a year to verify water level measurements and change the meter batteries, if required. Batteries have seen a life of 19 months, and are expected to last 2 years on the once-daily monitoring frequency (Drage & Kennedy, 2020).
References
Real-time Groundwater Monitoring via Internet of Things Platform
Summary
In southwestern Nova Scotia, most residents rely on domestic wells for their water supply, around 30% of which are shallow dug wells. There is a notable lack of up-to-date information on groundwater levels and many existing wells are not able to provide regular updates on aquifer water levels. The Nova Scotia Geological Survey developed a real-time, shallow groundwater level monitoring network for dug wells to help fill data gaps.
The solution is cost-effective as it relies on volunteers and their wells, along with a Wifi or cellular network connection. The water level meters transmit water level data in real-time via an Internet of things device, and the system costs approximately USD 150 to 225 for wifi and cellular models, respectively. There are a few challenges associated with the model, however, there are compelling solutions that address them, and the benefits of citizen science are worth exploring in further depth.
In southwestern Nova Scotia, most residents rely on domestic wells for their water supply, approximately 30% of which are shallow dug wells of less than 8m in depth that are vulnerable to water table declines (Drage & Kennedy, 2020). During droughts, similar to the 2016 drought which came in as part of the driest summer in 137 years, there is a need for emergency management staff and the public to have up-to-date information on groundwater levels. However, the existing provincial groundwater observation well network, which consists of 40 drilled wells spread out across the province, was not equipped with real-time monitoring equipment and, therefore, not able to provide regular updates on aquifer water levels (Drage & Kennedy, 2020).
Issue
Intervention
In response to the need to obtain real-time monitoring data, the Nova Scotia Geological Survey developed a real-time, shallow groundwater level monitoring network for dug wells so that up-to-date data would be available to help manage future droughts (Prentiss, 2018; Drage & Kennedy, 2020). The data from the network is also used to validate a provincial groundwater drought impact prediction model (Drage & Kennedy, 2020). Moreover, the challenge of obtaining regular measurements by relying on citizen science is overcome by automating the data collection process, however, the project did require volunteers who had dug wells located near their homes. Volunteers were recruited for the project by word-of-mouth, newsletter blurbs and radio and TV interviews (Drage & Kennedy, 2020).
To keep costs low, the water level meter developed for the project was based on a simple, do-it-yourself meter for measuring water levels in a household water storage tank and deployed in a network of domestic wells provided by community volunteers. The meter has four main components: an ultrasonic sensor to measure the depth to groundwater level , an Internet of Things (IoT) device to control the sensor and transmit the water level data to the Internet to be stored and viewed, a battery pack and an antenna (Drage & Kennedy, 2020). All pieces of equipment are readily available from online retailers (Drage & Kennedy, 2020). At the time of the study, the meters were programmed to measure and report water levels once a day, although any monitoring frequency can be used (Drage & Kennedy, 2020).
The water level meters transmit water level data in real-time to the Internet using the private wifi network at each volunteer's house, which requires the well to be located within approximately 50m to the modem. In cases where the wifi signal is too weak, an external antenna can be attached to the water meter and/or a wifi range extender can be installed in the volunteer's home, costing an additional USD 25 and USD 30, respectively (Drage & Kennedy, 2020). Real-time data transmission costs are also kept low by the use of, in most cases, the volunteers' home wifi. As an alternative, a cellular version of the water meter has also been developed for situations where no wifi network is available, though it is more expensive to build and operate compared to the wifi version, with parts costing approximately USD 225 (compared to USD 150 for the wifi version) and an additional USD 3/month for the data plan (Drage & Kennedy, 2020). Similar commercially available meters cost USD 2,500 each.
Challenges
While the meters have generally performed well in the field, there are a few challenges that have been identified. First, the meters require a wifi/cellular connection, which could be challenging for scalability in low-resource contexts. Similarly, the reliance on a wifi network means that any changes to said network (i.e., network name or password change), means the water meters can no longer connect to the Internet and therefore requires a field visit to update the meter (Drage & Kennedy, 2020). Second, if the meters face connection issues, data is not transmitted and is permanently lost due to no data logger (Drage & Kennedy, 2020). While a data logger could be added to the meter, this would increase the associated costs. The third and fourth noted challenges relate to the environment in which the meters are implemented. The third challenge is inaccurate water level measurements in dug wells constructed with rock walls. While new dug wells are generally constructed with casing made of precast concrete rings, older wells with rock walls likely cause the ultrasonic signal to reflect off the walls, though this can be remedied by installing a PVC pipe 75mm in diameter into which the meter can be inserted (Drage & Kennedy, 2020). Finally, the study found that frost formation on the ultrasonic sensor caused incorrect water level measurements (i.e., depth to water was reported as 0). This problem can be fixed by installing water meters 1-2m below ground level, however, this challenge would likely not be seen in warmer climates (Drage & Kennedy, 2020).
Outcomes
The network has been successful in monitoring groundwater levels in dug wells and real-time meters (Drage & Kennedy, 2020). Data shows a typical annual pattern observed in shallow aquifers across the province, with higher groundwater levels in the winter and spring (January to May), followed by a summer groundwater recession (June to August) when precipitation and recharge rates are low, followed by rising water levels in the fall (September to November) when rainfall returns (Drage & Kennedy, 2020). Moreover, the recruitment program was successful in attracting more volunteers than could be accommodated. The first wells were added to the network in 2017 and additional wells were added in 2018 and 2019. Ten wells use a wifi version of the meter and one uses a cellular version (Drage & Kennedy, 2020). Wells are also visited once a year to verify water level measurements and change the meter batteries, if required. Batteries have seen a life of 19 months, and are expected to last 2 years on the once-daily monitoring frequency (Drage & Kennedy, 2020).
Issues |
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Water Scarcity and Access |
Solutions |
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Water Data, Monitoring & ICT Solutions |
References
Drage, J., & Kennedy, G. (2020). Building a Low-Cost, Internet-of-Things, Real-Time Groundwater Level Monitoring Network. Nova Scotia. Retrieved June 27, 2022, from https://novascotia.ca/natr/meb/data/pubs/cs/cs_me_2020-001.pdf
Prentiss, M. (2018, August 20). With more droughts predicted, province creates real-time tracker for Well water | cbc news. CBC. Retrieved June 27, 2022, from https://www.cbc.ca/news/canada/nova-scotia/with-more-droughts-expected-province-creates-real-time-well-water-tracker-1.4787486