At the places where erosion has cut through the Roubidoux sandstone layer,
the valleys of the Bryant and its tributaries begin to look different.
Where the streams cut through it, the sandstone layer forms stairstep
rapids, waterfalls, and "box canyons."
As you continue down from this point, you will usually see
sandstone bluffs along and above the stream level. The harder sandstone
forms a cap rock that protects the softer underlying rock layers. This
allows the stream walls to be very steep, forming the bluffs commonly
seen along the streams. These bluffs are always most prominent on the
outside of a meander curve.
The Roubidoux formation is a major water-bearing layer (aquifer)
and springs are common where the stream valleys cut through it.
Northern Headwaters of the Bryant
The northern headwaters of the Bryant and its tributaries
begin along the southern edge of Wright County, south of Mansfield and
Norwood, and in extreme southeastern Webster County, south of Cedar Gap.
Here the Bryant headwaters are actively eroding into the southern margin
of the Springfield-Salem plateau. This produces a distinct irregular "rim"
or break in topography between the relatively flat Springfield-Salem plateau
and the very rugged topography of the Bryant watershed. The Bryant's share
of this rim extends eastward from Cedar Gap, past the southern edge of
Mansfield and Norwood, to the southern edge of Mountain Grove. The rim
continues on to the east past Cabool, marking the head of the North Fork
watershed, Bryant's sister stream. This rim also extends westward from
Cedar Gap to Dogwood and beyond. Here it is at the head of the Bryant's
neighbor to the west, the Beaver watershed.
Stream Gradients - How the Bryant Drops From its Beginning
at Cedar Gap Down to Where it Joins the North Fork
Lead Hill, in the area of Cedar Gap on the northwest edge
of the Bryant watershed, is 1,744 feet high, the second-highest point
in the state. (The only higher point is Taum Sauk Mountain of the St.
Francis Mountains of eastern Missouri, which is about twenty feet higher.)
The elevation of the surface of Norfork Lake, just below the junction
of the Bryant and the North Fork at Tecumseh, is at 546 feet. The difference
in elevation is approximately 1,200 feet --- a considerable drop if you
measure it "as the crow flies," which gives a linear (straight-line) distance
of 39.5 miles.
If you divide the 1,200 foot drop by this linear distance
of 39.5 miles, you get a stream gradient of just over 30 feet/mile. Of
course the Bryant does not flow "as the crow flies", but does a lot of
of meandering (winding), which probably just about doubles the distance.
The actual distance that a drop of water flows as it travels from the
top of Lead Hill to where the Bryant joins the North Fork is 70 miles.
This gives an average stream gradient of 17 ft/mi. (1,200 feet divided
by 70 miles.)
However, for its first five miles of headwaters, the Bryant
is an "intermittent stream," appearing and then disappearing underground.
Over this first five miles the elevation drops by 624 feet. This gives
it the very steep stream gradient of 125 ft/mi! Over the remaining 65
miles the elevation drops by just 560 feet for an average gradient of
8.7 ft/mi. This great difference in gradient between the headwaters of
Bryant and the main channel of its lower 65 miles shows up in the way
stream erosion has shaped the land over the first 5 miles and the lower
It is interesting to note that water that flows off the
north side of Lead Hill goes into the Gasconade watershed, the Bryant's
neighbor watershed to the north. This water ends up at the Missouri River
after traveling 260 miles downstream. Over this 260 miles the elevation
drops by about the same amount as the Bryant, 1,200 feet. This gives the
Gasconade an overall stream gradient of about 4.5 ft/mi. As you might
expect, this gradual drop creates a less rapid flow and produces a considerably
less rugged topography than the Bryant does.
Caves And Sinkholes
Another important feature in the Bryant watershed is the
common occurrence of caves and sinkholes. The dominant rock
type in the area is carbonate rock. Carbonate rocks are subject to
solution or dissolving by groundwater. This produces cavities or caverns
in the rock, which may be seen as caves in hillsides or a collapsed caves
or "sinkholes" in relatively flat areas.