On my return walk on an old rice field dike a juvenile Yellow-crowned Night-Heron was perched on another trunk, this time up on a cross bar amidst some spider webs.
The pressure-treated look of the wood and use of metal material indicate that is a newer, replacement trunk. Older ones are all wood, including the pegs that position the water control flap.
Juvenile Yellow-crowned Night-heron on Trunk
Management of these wetlands by the SC Department of Natural Resources is dependent on the functionality of these trunks for water level control.
Bear Island Wildlife Management Area, SC
July 4, 2021
Rice field trunks play a big role in controlling water movement in many of the South Carolina areas I explore. Once used for growing rice, private land owners and the SC Department of Natural Resources currently manage thousands of acres of wetlands using this time-tested method. Dikes separate what was a rice field from a major body of water and the trunk is used to move water back and forth.
Last week the water had been let out of the Magnolia Plantation & Gardens boat pond, so named because they give nature tours by boat around the pond. To give you an idea of the size, the perimeter of the pond is about 1.75 miles (3 KM). The pond is a mixture of open water and cat tails / reed clumps. Two years ago the boat channel was dredged and the water seen in the first image is in that channel.
With the low water I was able to get some images of the trunk parts that are normally under water.
Boat Pond, Water Out, Tour Boats Sitting On the Mud
There is a wooden box creating a culvert under the dike (think cereal box laying on its side). I have read that these are called trunks because in colonial times hollowed tree trunks were used to conduct the water.
The lower paddle ends of the flaps, which pivot at the top, are adjusted to manage the water flow.
Rice Field Trunk, Great Blue Heron in the Water, Ashely River on the other side
The Ashley River is tidal, so with both ends of the trunk wide open at low tide the water drains out of the pond. Then with at least one end of the trunk closed as the tide turns the water in the pond will remain low. The seals on either end are not tight and there is always some water movement.
Leaving the trunks ends open will refill the pond as the tide raises the water level in the river. Sometimes they are left open for days to wash out the pond or change the salinity level.
Rice Field Trunk, Ashely River On The Other Side of the Dike
The bonus to all this for the nature photographer is that wading and shore birds are attracted to the lower water. Fish are concentrated in a smaller volume making hunting easier and they can poke around in the mud.
A Black-crowned Night-heron was perched on the edge of one of the trunks that controls water flow from this pond to the marsh on the other side of the road. The hunting is often very easy near the trunks as small fish gather in the moving water which attracts a whole food chain.
I got a little wet walking around the old rice field pond and then was treated to a rainbow. I didn’t see the second, fainter rainbow until I was developing the images.
Double Rainbow Over Ashley River
The sun came out, I continued on then another shower, another rainbow. The sun nicely lit the trunk that connects the pond to the Ashly River.
Rainbow From Magnolia Rice Pond
November 6. 2020
Magnolia Plantation Rice Field Pond, Charleston, SC
From the SC Encyclopedia: scencyclopedia.org/
Rice trunks are wooden sluices installed in “banks” or dikes of rice fields for irrigation or flood control. They are long, narrow, wooden boxes made of thick planks, and each has a door at each end. Hung on uprights, the swinging doors, called gates, may be raised or lowered to drain or flood a field.
The gates of rice field trunk, which controls the flow water from the Ashley River into the pond to the left, is surrounded by a yellow and gold fall glow.
This wooden “trunk” controls water flow to and from the old rice field pond seen here and the tidal Ashley River, just at my back as I took this image. A variety of wading birds have become accustomed to stopping by; when the water is flowing through the trunk the fishing can be pretty easy on the low side.
