EasyQ

River Velocity and Stage Monitor

Single, small sensor, mounted below the surface provides all the data you need to monitor the flow in a river or channel:




  • Flow velocity at three points across the river or channel (V1,V2,V3)
  • Vertical beam measures water level (stage) using its patented process. ( US Patent 6345683)
  • Down beam monitors channel bed erosion or growth of vegetation
  • Reflection coefficient of the acoustic signals may be used as an indication of local turbidity
  • Profiling range up to 30 meters from the instrument.
  • Only 75 mm diameter, 590 mm long.
  • Weight in air: 1.7 kg with alkaline batteries, 0.7 kg buoyant in water.
  • Materials: Plastic and titanium
  • Built-in SDI12 Interface
  • Available in two frequencies: 2 MHz (6-14 m profiling range) and 1 MHz (14-30 m profiling range).
  • NEW: DirectQ interface. Direct output of flow velocities, discharge and stage in digital format (RS-232 or RS-422) or as analog signals (0-5V or 4-20 mA).
  • Also available as a simpler, velocity-only sensor: the EasyV

The EasyQ represents a new approach to river and channel flow measurements where multiple acoustic sensors are combined in a single instrument. First, the EasyQ is 3-cell current profiler that measures the velocity out in the middle of river, away from the direct influence of the banks. Second, the EasyQ is a high-precision acoustic stage sensor that meets the USGS specifications of 3-mm accuracy (1/100'). Third, the EasyQ's fourth beam is configured as an echo sounder that allows you to observe changes in the channel bed or the vegetation growing in from the banks.


In standard applications, the EasyQ mounts on the sidewall with one acoustic beam pointing toward the surface (stage), two pointing perpendicular to the river flow (3-cell velocity) and the fourth beam pointing toward the bed. Data can be recorded at user-selectable rates and stored in the internal recorder or sent to a data logger using the SDI-12, RS-232 or RS-422 serial interface. The post processing normally includes a user-supplied model of the river (including the detailed cross section area) and the approximate velocity profiles (vertical and horizontal) before a final Q is derived for the river or channel flow. The method applied is usually referred to as the Index Velocity Method

As with all Nortek products, the EasyQ comes with free Windows PC software that offers a simple and standardized method for setting up the sensor. It guides you through the process from configuration to data collection to data conversion, and displays numerical and graphical data online. The software also includes stage and range test modes for quick and simple installation assistance.

Velocity:

The EasyQ measures velocity in three adjacent cells with two horizontal Doppler beams looking sideways into the flow. You can adjust the position of the measurement cells to place them close to the sensor or further out in the river. The velocity is averaged over a programmable interval, ranging from one second to one hour. The carefully implemented Doppler processing gives you better than 1% measurement accuracy.

Stage:

Stage is measured with a vertical echo sounder that finds the strong echo off the water surface. The measurements are assisted by the pressure sensor to reject out-of-range echoes from debris in the water. The measurement is insensitive to atmospheric pressure changes, and does not require vented tubes. Averaging over intervals of typically 1 second to 2 minutes filters out the effects of waves.