Development of an Automated Groundwater Monitoring System Using a Wireless Based Sensor Array Deployed in a Groundwater Monitoring Well

Abstract

Abstract Protection of groundwater resources in Saudi Arabia is of vital importance as the Kingdom's aquifers supply over ninety percent of water use in the country, are essentially non-renewable due to the arid climate, and, if impacted, can pose risks to human health and the environment. As part of its corporate-wide groundwater protection program, Saudi Aramco actively monitors shallow groundwater at many of its operating facilities, primarily through a network of hundreds of groundwater monitoring wells. Groundwater sampling and laboratory analysis occurs on a periodic basis each year to monitor groundwater quality changes. Limited staff and laboratory resources pose challenges in meeting this objective and a practical solution was required. This paper presents a solution to these challenges by development of an automated, standalone measurement system deployed in groundwater monitoring wells using a multi-parameter sensor array package. A key feature included an ultraviolet (UV) fluorescence sensor that can measure dissolved-phase aromatic hydrocarbons at microgram per liter concentrations. Combined with data logging and wireless capabilities, the deployed system enables real-time and remote monitoring of groundwater quality from standard 4-inch diameter monitoring wells. Prior to field deployment, a series of laboratory bench-scale calibration profiles were developed for the UV-fluorescence sensor to determine sensitivity to typical Saudi Aramco hydrocarbon streams. A complete prototype system was then constructed and placed in an active groundwater monitoring well. This paper discusses the results of the laboratory calibration and field evaluation, including performance monitoring of individual array components, development of power budgets to match data logging requirements with solar power generation, data transmission and remote system management via Ethernet-to-wireless communications, and long-term system performance in a harsh (high temperature, humid and dusty) environment. The benefit of this system allows for automated (and more frequent) monitoring of sensitive and remote areas, enabling prioritization of staff and laboratory resources where they are needed the most.