These instruments are available for the
Em3 and Em4 models:
A 12 V powered dye injection system consists of two 2-liter reservoirs feeding into solenoid valves. Dye pulses may be injected using two switches on the pump cart. Dye pulses may also be automated.
Dye pulses allow for better visualizations of water movement in a stream system. The dye allows observation of how streambed characteristics affect stream flow. For example, concentrations of dye in the channel indicate location of the thalweg. When the dye pulses, the user can observe how the thalweg changes over time.
The groundwater system allows for injection and extraction of subsurface flow from the model. A small 60psi pump supplies a spray bar at the upstream end of the box to produce the groundwater flow. Extraction filters are installed at the downstream end of the box. The extraction filters connect to tubes that empty into the reservoir. The extraction tubes have valves allowing the user to increase, decrease, or turn off groundwater extraction.
The groundwater system allows simulation of a wider range of landscapes. For example, to simulate an influent (or losing) stream, the valves can be opened to extract groundwater. The valves can also be closed to show impacts of a gaining stream on stream characteristics. Different combinations of groundwater extraction rates in either of the two extraction filters provides the opportunity to study many different stream scenarios.
The media feeders are sophisticated, computer-controlled cone valve feeders to precisely add media to the model’s inflow and provide the opportunity to simulate more landscapes and the impacts of disturbances on the stream system. The media feeders can have one to four hoppers depending on inputs desired. Multiple hoppers allow input of various sediment sizes into the system. A single hopper can be used with either the mixed color-coded media, or the non-coded media.
Media feeders allow manipulation of sediment supply to the system. If a state of equilibrium is desired, rate can be manipulated so sediment “in” is equal to sediment “out” of the stream system. The user may be interested in viewing the impacts of large erosion events upstream and how stream characteristics will change.
MAGNETIC FLOW METER
An Omega FMG3000 series or equivalent electromagnetic metering system provides precise flow measurement over the complete range of flows (1% error). Magnetic flow meters monitor velocity of an electrically conductive fluid without obstructing flow. The digital output of the system enables electronic monitoring and control.