Monitoring Suspended Sediment - Coney Island CreekProject Overview
Coney Island Creek is a sea inlet separating the western portion of Coney Island from the main body of Kings County, New York. In the early 1900s, a tire factory near Coney Island Creek contaminated the Creek by dumping benzene and other hazardous chemicals.
In an effort to dredge the contaminated sediment from the Creek, a New York consulting firm contacted NexSens Technology for assistance on designing and implementing a real-time turbidity dredge monitoring system.
System Description
The water level in Coney Island Creek fluctuates drastically daily based on tides. Due to sediment buildup, many areas of the creek completely dry up during low tide. Therefore, a typical buoy-based dredge monitoring system was not feasible in all areas of the Creek. To combat this issue, NexSens engineers developed unique float kits to keep the turbidity sensor from getting covered in muck during low tide.
The float kits are designed to surround a 2" deployment pole that is permanently installed into the creek bottom. As water level fluctuates, the float rises and lowers along the pole. A tether prevents the turbidity sensor from becoming covered in muck during low tide. Additionally, top and bottom eye nuts make it easy to connect various sensors and equipment.
To measure turbidity levels, the consulting firm chose the OBS-3+ Turbidity Sensor from Campbell Scientific (formerly D&A Instruments). This compact sensor uses the optical backscatter method to measure turbidity and suspended solids. Additionally, the OBS-3+ features a wet-pluggable connector for worry-free use in the field.
During the dredging operations, data is collected at constant intervals and sent through license-free radio waves to the base station, where turbidity levels are closely monitored using iChart 6 Software. According to regulation, the inlet/outlet of the creek cannot be 25 NTU higher than the middle and end of creek. If this does occur, dredge operators are immediately notified to slow down or cease operation. | NexSens 1001 | iChart software | NexSens WQData-6 | Annual data hosting package for up to 6 field sites, additional site expansion available | NexSens 4100-BASE | Spread spectrum radio base station | NexSens A44 | High gain antenna, radio frequency, 3 dB | NexSens A31 | RF cable, low-loss, 10' | NexSens MB-300 | Monitoring buoy, 30" dia. polymer-coated foam hull, 300 lb. buoyancy | Carmanah 501-A15 | LED Beacon with solar power, 15 flashes per minute (064), amber | NexSens 4100-iSIC | iSIC data logger with spread spectrum radio telemetry | NexSens A20 | Solar power kit, 5-watt. Includes solar panel, regulator, 8.5 A-Hr battery & watertight enclosure | NexSens A44 | High gain antenna, radio frequency, 3 dB | NexSens A36 | RF cable, micro-loss, 6' | Campbell OBS-3+-SB-2.5-T2 | OBS-3+ Turbidity sensor with stainless steel housing (500m depth), 0-2.5V output, 0-500 NTU (low range), 0-2000 NTU (high range) |
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