Groundwater starts as precipitation, and the portion of the rain water that infiltrates beneath the ground’s surface, either naturally or artificially, becomes groundwater. The remaining precipitation is used by plants, evaporates, or becomes surface water runoff which can either add to groundwater levels in other areas or be increased by groundwater outflows depending on the geology the surface water travels through.
Groundwater is critical to the communities that are built on or near an aquifer, or the underground layer of water that fills cracks in the rock or sand that makes up the soil. This groundwater layer which makes up about 30% of the world’s freshwater supply is used for many purposes including irrigation, private drinking water, and municipal water supplies.
Groundwater is a key part of a country’s ability to irrigate its farmland. Irrigation systems account for the use of about 53.3 billion gallons of groundwater per day. This usage can be compared to the 1900s when the US only used 2.2 billion gallons per day for irrigation.
Information regarding groundwater use for drinking water worldwide is limited, however it is estimated that one-third of the world’s population depend on groundwater as the main source of their drinking water. Over 13 million US households regularly depend on private groundwater wells.
Groundwater sources are used by about 33% of the public water systems in the United States. Between public and private water wells about 44% of the US population depends on groundwater for their drinking water. Including drinking water and farming, along with other uses of groundwater such as manufacturing, mining, and thermoelectric power to name a few…79.6 billion gallons a day of fresh groundwater are used.
Knowing the groundwater level is important for several reasons, including understanding aquifer levels under static and pumping conditions, determining how the levels interact with local surface water sources, and understanding how surface development has impacted the aquifer.
A groundwater well may have high water levels; however it may still be unsuitable for drinking water. Water can easily become contaminated because it is a very good solvent and can contain many dissolved chemicals. Rainwater or surface water can come into contact with contaminated soil while seeping into the ground, from that point it can become polluted and carry the pollution from the soil to the groundwater aquifers. Groundwater can also become contaminated when liquid hazardous substances soak down through the soil or rock.
One source of groundwater contamination often overlooked by the general media is contamination from naturally occurring chemicals found in the surrounding rock and soil. Groundwater is not static and as it moves through the ground it dissolves the rock and soil along with any chemicals they may contain. For example, toxic chemicals such as arsenic and selenium are common in some types of rock formations and groundwater near those sites should not be used as drinking water sources until it is treated.
Water Level Sensors
Smart PT delivers accurate results for a wide range of fluid level measurement applications. In addition to simple instantaneous measurements, this smart sensor features the ability to capture peak crest levels, and to automatically sample and report basic statistics on a configurable time interval.
Extremely rugged design—potted electronics, high-impact PVC housing—make the SDX an excellent choice for hostile environments and applications that may put more expensive sensors at risk of damage or loss.
- Will not be damaged by freezing water.
- Vented cable provides an atmospheric reference.
- 4-20 mA output.
Pressure sensors (also called pressure transducers or pneumatic pressure sensors) preform liquid level measurement by having the sensor submerged at a fixed depth under the water surface. The pressure sensor measures the equivalent hydrostatic pressure of the water above the senor diaphragm, using this to calculate the total liquid depth. This function of a pressure sensor can be compared to “weighing the water”. Pressure sensors are ideal for ground and surface water level applications.
Water Quality Sensors
This SDI-12/RS-485 sensor is ideal for high-accuracy readings in water, soil, and air. It features fully-potted components, robust PVC Type II housing, and marine-grade stainless steel, making the sensor ideal for harsh environments.
Stevens groundwater monitoring stations will typically use either cellular or GOES for telemetry. For cellular (CDMA/GSM/HSPA), both Avo and eTracker are cellular gateway which provide “virtual” cloud-based data logging, and therefore don’t require a physical data logger. All data is sent to the cloud for storage (with a backup stored locally) and the station can be configured remotely.
Stevens offers 4 different options for connecting you with your system’s data:
Because it is an all-in-one solution requiring only sensors, Avo is a great solution if the station is going to be only temporary, where a simple and quick station setup is important or where data reliability is critical. Avo sends data directly to the cloud (via cellular) where it is logged, so does not require a separate data logger.
eTracker also sends data directly to the cloud via cellular where it is logged, so it doesn’t require a separate data logger. Choose eTracker if you want to customize what power system components are used, or will be using a greater number of sensors than Avo supports.
Cell-Net is a good choice if you want a 2-way cellular connection to your sensors and ability to access your data on the cloud (like Avo and eTracker) but want to use a separate data logger or already have smart (logging) sensors.
If your station is in a very remote location without a cellular signal, then GOES is the best option. It also may make sense if you don’t want monthly service charges, your data payloads are small and you don’t need access to data more than once per hour. You can use a separate logger, or it’s available with one integrated.
Retrieving data is simple with Stevens-Connect, our cloud-based software that requires no infrastructure to scale to any number of stations or users. Use it to configure your station, visualize your data, analyze measurements, manage alarms, perform calculations, and set up data routing. Alternatively, you can have the data sent to any other HTTP or FTP destination or 3rd-party software like Aquarius or WISKI.
Stations built on a platform other than Avo require a power source (battery and solar panel is typical for remote deployments) and a power regulator. SOLO is great choice because it’s a solar charge regulator, intelligent power manager and power system sensor all-in-one (it also allows remote power cycling through eTracker).