A head cut (alternately headcut
[ ]), in
stream geomorphology, is an
erosional feature of some
intermittent and
perennial
A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wid ...
streams. Headcuts and
headward erosion
Headward erosion is erosion at the origin of a stream channel, which causes the origin to move back away from the direction of the stream flow, lengthening the stream channel.Essentials of Geology, 3rd Ed, Stephen Marshak It can also refer to ...
are hallmarks of unstable expanding drainage features such as actively eroding gullies.
Headcuts are a type of
knickpoint
In geomorphology, a knickpoint or nickpoint is part of a river or channel where there is a sharp change in channel slope, such as a waterfall or lake. Knickpoints reflect different conditions and processes on the river, often caused by previous ...
that, as the name indicates, occur at the head (upstream extent) of a channel.
[ ]
The knickpoint, where a head cut begins, can be as small as an overly-steep
riffle
A riffle is a shallow landform in a flowing channel. Colloquially, it is a shallow place in a river where water flows quickly past rocks. However, in geology a riffle has specific characteristics.
Topographic, sedimentary and hydraulic indica ...
zone or as a large as a
waterfall
A waterfall is a point in a river or stream where water flows over a vertical drop or a series of steep drops. Waterfalls also occur where meltwater drops over the edge of a tabular iceberg or ice shelf.
Waterfalls can be formed in severa ...
. When it is not flowing, the head cut will resemble a very short
cliff
In geography and geology, a cliff is an area of rock which has a general angle defined by the vertical, or nearly vertical. Cliffs are formed by the processes of weathering and erosion, with the effect of gravity. Cliffs are common on co ...
or
bluff
Bluff or The Bluff may refer to:
Places Australia
* Bluff, Queensland, Australia, a town
* The Bluff, Queensland (Ipswich), a rural locality in the city of Ipswich
* The Bluff, Queensland (Toowoomba Region), a rural locality
* Bluff River (New ...
. A small
plunge pool
A plunge pool (or plunge basin or waterfall lake) is a deep depression in a stream bed at the base of a waterfall or shut-in. It is created by the erosional forces of cascading water on the rocks at formation's base where the water impacts.Mars ...
may be present at the base of the head cut due to the high energy of falling water. As erosion of the knickpoint and the streambed continues, the head cut will migrate upstream.
Groundwater
seeps and
springs are sometimes found along the face, sides, or base of a head cut.
[North Carolina Division of Water Quality, "Identification Methods for the Origins of Intermittent and Perennial Streams, Version 3.1", February 28, 2005] incision is very common when head cuts are involved in stream morphology. In terms of stream restoration, head cuts are one of the most difficult challenges. Installing
check dam
A steel check dam
A check dam is a small, sometimes temporary, dam constructed across a swale, drainage ditch, or waterway to counteract erosion by reducing water flow velocity. Check dams themselves are not a type of new technology; rather, th ...
s or elevating the stream by filling the gully are common ways to mitigate up stream migration of the knickpoint. Another common way to control the knickpoint is by sloping the bank face by laying down fabric and rock.
References
{{Reflist
External links
* North Carolina Division of Water Qualit
Stream restoration problems
Geomorphology
Fluvial landforms
Erosion landforms