Understanding the Kuhn Weir
Focus on the word – WEIR – Number 1 – in the diagram below
Notice the I-75 highway in the picture. Lock visually onto Number 1, it’s important.
This part of the Red Run Drain is buried underground
You’ll see the I-75 Highway in the background.
Picture below says Detroit, it’s really Madison Heights, MI
Weir is a specific unique type of low small dam to control water by
not only obstructing it, but also by letting water flow over it.
The water collected behind the obstruction can be diverted elsewhere
and the water that spills over it can be directed as well.
Sometimes geometric shaped notches like a rectangle or v-shape
are used at the top of a weir to direct the thrust of the water.
It is a passive device, functioning strictly on water level.
By confining, restricting, directing the water to a narrow portion of the weir,
via a notch, v-shape, etc. ; the weir equations are a bit easier to figure out
and give more accurate results because of inevitable errors in measuring
the large cross sectional area of wide, shallow, streams and rivers.
If someone had a stream running through a property and they
wanted to create a pond, they would install a weir.
The water would back up the flow until the desired pond level was reached,
and then any excess would overflow needing a directional channel.
~~~~~~~~~~~ click with mouse to enlarge ~~~~~~~~~~~~
SIMPLIFIED view :
In dry weather, runoff from 27 square miles across 14 communities
is routed to the Detroit Wastewater Treatment Plant via a pipe
at 12 Mile and Stephenson — where the WEIR is located.
When very heavy continual rain causes some sewage
from those multiple communities in Oakland County
(over 90 percent of which is actually storm water)
to exceed the physical capacity to Detroit,
the excess flow tops a weir
and is diverted to the 2.2-mile-long underground GWK basin.
The G.W.Kuhn is a Retention facility, it only temporarily holds water a few hours.
Here the solid waste is thoroughly separated and removed.
The water gets pumped back to Detroit.
The Kuhn Retention Basin is in Madison Heights, Oakland County.
Dequindre Road is the physical county boundary.
Low Flow – Red Run meandering below Ryan Road in Warren, MI
High Flow – Red Run very strongly flowing under Ryan Road Bridge in Warren, MI
If the volume is so high that it tops the second weir,
the excess is disinfected by carefully controlled amounts
of sodium hypochlorite, similar to swimming pool chlorine
or household bleach. The chemical is dispensed through
plastic pipes and titanium pumps connected to eight tanks
in a secure room, with each tank holding 18,000 gallons.
From there the water, now clean, heads toward Dequindre.
If it tops the third weir, it’s back to Lake St. Clair
via the Red Run Drain, a tributary of the Clinton River.
And from there it’s off to the Great Lakes.