Another wooden trunk between some old rice fields, this one controls the flow of water from the canal in the foreground to the impoundment behind that dike. This set of trunks was replaced last year and only this side has the full pivoting door mechanism.
I knelt down to get the next image, where you can see open water in the impoundment on the other side. The grackle and the Tricolored Heron had moved on and the juvenile night heron took that opportunity to claim a post.
Bear Island Wildlife Management Area, SC
September 14, 2022
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.
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.
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.
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.
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.
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.