River and Estuary Observatory Network (REON)
Beacon Institute first deployed B1 -- the first sensor array for the REON system -- in the Hudson River off Denning's Point in Beacon, NY (Latitude: 41° 29' 39.60” N, Longitude: 73° 59' 23.88” W) on August 20, 2008. The sensor array was gone through several redesign phases in the past few years and we have redeployed in 2013. It is moored with a four point tension mooring system that includes four 300 lb mushroom anchors. The shackles and chains of mooring adjust tension on the platform based on water and wind conditions, much like the way shock absorbers smooth the ride of an automobile.
PV panels provide solar power to batteries on deck, which power everything on the sensor platform including the wireless communications. The computer-controlled autonomous robotic profiler enables an array of multiple sensors to move up and down in the water for measurements.
An on-board computer receives information from the instruments and serves as a data logger, and relays commands to profilers. Remote programming allows for autonomous and cyber control of the sensor array. Also, the camera installed at the monitoring site takes a snapshot after every profile. When it gets dark, the IR lights turn on. They reflect off the inside of the camera enclosure so the photo is a bit dodgy, but at least the photo of instrument cage is clearly visible. The camera is tilt-swivel, so it can be repositioned as needed so that it can be turned around to explore the condition of instrument cage and monitoring site. The Snapshot from the latest profile is available in the following link:
Vertical profiles of observational data at Denning's Point for twenty four hours
(Data are presented with reference to EDT)
North component Current Profile
On B1, the Acoustic Doppler Current Profiler (ADCP) points downward toward the river bed and measures the direction and speed of the water current. Dark red at the bottom of the figure shows the variation in the depth of the river bed. Depth of water column changes with time due to forces of the tide. Positive velocity magnitude (yellow to red) indicates that water is moving up the river to the north – high tide. Negative velocity magnitude (turquoise to blue) shows water moving to the south, back toward the Atlantic Ocean – low tide.
North Component Current
Headings of ADCP
This scatter plot displays heading of ADCP sensor on the platform. If heading changes, it represents the angular movement of robotic platform while the platform is anchored at the fixed location of the bottom.
ADCP Heading (degrees)
This figure shows the variation of particle concentration at the platform over time. A strong current in either direction can move water and particles from bottom, and can also bring up particles from the ocean, as concentration can change with tidal forces. Normally the particle concentration is expected to be greater at bottom of the river, and less dense at the upper portions of the water column.
Volume Conc. (ul/l)
A meteorological sensor on the platform measures wind direction, flow and speed, as well as air temperature and barometric pressure.
(Wind Speed, Direction, Air Temp., Press)
A three-channel flurometer (FL3) is a unique instrument that provides data on the presence of biological, physical and chemical particles in the water. Chlorophyll concentration measured by FL3 provides an indirect measure of the phytoplankton biomass (algae). At certain levels, algae can be a food source, but an overabundance can be detrimental to the ecosystem. Red shows a higher concentration of phytoplankton biomass, blue is lower.
Chlorophyll Conc. (ppb)
CDOM: Color Dissolved Organic Matter
Also on the FL3 is a CDOM sensor which measures dissolved organic matter particles in the water. As a natural water mass tracer, the CDOM sensor measures how organic contaminants and metals distribute themselves in the river. Red shows a higher concentration of organic matter, blue is lower.
The optical oxygen sensor is uses optical fluorescence technology to detect the amount of oxygen in the water. Dissolved oxygen is an important indicator of ecological health. Red means low concentration of oxygen, blue means higher concentration of oxygen.
| Dissolved Oxygen
Conductivity and Salinity
Conductivity and salinity, while measured in different units, are both indicators of the amount of salt present in the water.
Red shows high tide, with high salt water concentration from the ocean. Blue shows low tide, with more fresh water
concentration. There is a slight amount of lag time with this parameter due to tidal variations.
In this figure, red indicates warmer water, while blue indicates colder water. Water temperature can vary with the tide
and time of day.
Water Temperature (deg. C)
In this figure, each red line represents measurement depth variation corresponding to each level of measurements. The profiler collects data at five different levels of water column.
Measurement depth variation with time
Particle size distribution
The following figures display particle size distribution at different depths of water column. The magnitude of particle concentration is presented here in color-coded shaded surface. The red color means higher concentration whereas blue color means lower concentration. Height of the surface also represents magnitude of particle concentration.
All data, photos and content copyright © 2009 Beacon Institute for Rivers and Estuaries. Unauthorized usage
or reproduction prohibited.