Investigating Spatial Distribution of Contaminants in River Systems

Professor William B. Kaiser, Principal Investigator
The Networked Infomechanical Systems (NIMS) Project

Networked Infomechanical Systems (NIMS) is a new robotic sensor technology that combines networking, embedded computing, and electromechanical systems. NIMS is a breakthrough in sensing technology, providing autonomous and precise control of sensors in complex environments. NIMS has been developed for many applications, including exploration of forest ecosystems with sensor nodes that sample atmosphere, measure solar radiation, and image plant systems. Recently, a new NIMS system was developed to directly provide the first "images" of the spatial distribution of contaminants and flow in river and stream systems. In collaboration between HSSEAS and UC Merced, this important NIMS RD investigation was completed at the San Joaquin River in the California Central Valley. Here, the NIMS RD system spanned 200 feet, crossing the river at a point 1km downstream from the confluence where the Merced River joins the San Joaquin. The sensors included many chemical and physical measurement devices, including sensors that indicate concentration of nitrate, ammonium, and salt contaminants along with acidity, temperature and flow measurements.

The NIMS RD system uses its cable actuation systems to both raise and lower the sensor package to depth in the river and scan across the river as well. Together, these measurements form a map or image. The distribution of water quality parameters measured by NIMS RD revealed a dramatic difference across the river mixing zone.

NIMS can now be deployed in many stream, lake, and river applications where the actual flow rate of individual contaminants can be determined. This is expected to be critical in determining the origin of frequently occurring salt contamination and the interaction of contamination with neighboring land systems, a current important concern in water quality management in California and the Western U.S.