FLOOD00235

• County: Statewide
• Community: State of Colorado
• Stream Name: All
• Title: Stream, Riparian, and Wetland Ecology - Class material, Volume 1 of 2
• Date: 9/1/1987
• Prepared For: Students
• Prepared By: Professor Windell
• Floodplain - Doc Type: Educational/Technical/Reference Information

35

bland is defined as a bar or land aelmenl: within tht! acre.. channel which
ia relatively stable, usually vegetated and normally surrounded by water.
Since the existence of bars depends upon the sizes of materials and water
flows, bars form in different types of channels, at dlifferent pOllit1ons and
under a variety of conditions. The most cobvious bars: can be seell in
braided channels.

Eight different types of bars have be:en defined (Figure 3). Braided
channels that transport high volumes of be:d material tend to crellte diamond
bars with high visibility during low flQws" Diamond bars become very
COiiSpicuous with numerous interconnected slnall channels during IClw flow. A
wave-like pattern of bars called dunes cODllDonly forlDS in relativl!ly active
streambed. dominated by sand. A junction bar is one that is formed at the
junction of two streams, usually because sediment transported by a
tributary is deposited in the slower moving water of the mainstream. A lee
bar is formed in the lee (downstrellll sheltered side) of large illlllovable
objects .uch .. boulder.'or log. due to back eddie. lAd lower CU1~ent
velocities. Mid channel bars are found in the IIlid-ch.annel zone riot

~

D1amontl/
Braidil18

----..--
~.'"i'..z';.;-- -
..........~

~.'~-

Uid-ehannel

-

~';:;Elr
~; Dunes

~~P01",

~L..

-

"..-.------
.-.----.

Sid",

~

~'=-

Junctiol'l

.-.-
...,- .~li!!i;- ~
.E'V't>'.
p-----

Yr.ntverall'

FIG~E a. BlIr TYPI!:5

From T.W. Challlberlin (ed). "PD Technical Paper 2, Aquatic Survey
Terminology. Irltbh Colu.bta Minhrry of EnvlroNllent, .'le:to-rh I.C.
30 pages.

extending completely scr088 the channel. Point bars lire those fOl~nd on the
island of meander bends. They may extend t~o form tranaverse bars in gravel
bed rivers. Side bars are located at the side of a stream channel, and
are usually associated with the inside of lllight CUrVE!S. Transverse bars
are those which extend diagonally across the full width of the active
stream channel.