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National River


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park geology subheading
Aerial photo of Buffalo National River
Buffalo National River, Arkansas

The rocks of Buffalo National River are entirely sedimentary, laid down in an ancient marine basin. Over its 300-million year history it was variously uplifted and eroded and then again submerged below the sea to receive more deposits. Deposition of the strata was discontinuous, and unconformities have been left in the sequence. Most of the rocks contain invertebrate fossils - trilobites, brachiopods, crinoids, cephalopods. Today the rocks are again uplifted and superimposed on them are high bluffs, waterfalls, springs and hundreds of solution pits and caves. Two features are especially noteworthy; one, the 200-foot waterfall in Hemmed-in-Hollow, which is the one of the highest in the entire region between the Appalachians and the Rocky Mountains; the other, the gypsum formations of Beauty Cave (NPS, 1977).

The basin is underlain by gently folded sandstone, shale, cherty dolomite, and limestone of Pennsylvanian to Ordovician age (Figure 8 and 9). Unlike most Ozark streams, the Buffalo River's watershed contains a substantial amount of sandstone and shale (Table 3). The Pennsylvanian sandstone and shales occupy a large part of the upland, particularly in the upper basin. Most of the river itself is underlain by the St. Peter sandstone and Everton Formations. The prevalence of sandstone and shale, as well as the relatively small amount of chert in the upper strata, substantially affects the size and availability of transportable sediment (McKenny, 1997).

Typical of the Ozarks region, approximately 64% of the basin is underlain by limestone and dolomite formations (Scott and Smith, 1994). The Boone formation, a karstic cherty limestone formation, occupies the largest part of the basin (31.8%) and underlies many tributaries and a substantial part of the mainstem of Buffalo River (Scott and Smith, 1994).


The Buffalo River has cut deeply into the bedrock, leaving tall, vertical bluffs standing at river bends (Figure 6). In some areas the river is confined by bedrock; in others it meanders through alluvial bottoms. The channel is vertically stable as the bedrock is either exposed or covered with a thin layer of gravel and sand (Adamski et al., 1995). The river is characterized by quiet pools separated by short riffles. From Ponca to Pruitt the river falls an average of 13 feet per mile. From Pruitt to Highway 65 the average gradient is 5 feet per mile, and from there to the mouth it is about 3 feet per mile (NPS, 1977). The elevations within the Buffalo River watershed range from 2,576 feet above sea level in the Boston Mountains to 351 feet above sea level where the Buffalo River empties into the White River (Figure 7). The hills or ridge tops surrounding the river are usually narrow and winding, the sides alternate in steep slopes and vertical escarpments (Scott and Smith, 1994).

The watershed is characterized by three physiographic regions, the Springfield Plateau, the Boston Mountains, and the Salem Plateau (Adamski et al., 1995). The Springfield Plateau occupies about 47% of the Buffalo's watershed and is underlain by limestone and cherty limestone of Mississippian age. Land surface altitudes range from 1,000 to 1,700 ft but locally topographic relief rarely exceeds 200 to 300 ft (Adamski et al., 1995). Sinkholes and springs are common in this region. The Boston Mountains occupies 34% of the watershed. They are underlain by sandstone, shale, and limestone of late Mississippian to Pennsylvanian age. Land surface altitude ranges from 1,200 to more than 2,300 ft above sea level and topographic relief is as much as 1,000 ft in some places (Adamski et al., 1995). The topography is rugged with narrow divides separating steep-sided valleys. Finally, the Salem Plateau occupies 19% and is underlain by rocks of the Cambrian and Ordovician age although the Cambrian rocks are not surficially exposed with the watershed. The upland is characterized by gently rolling hills and local relief is 50 to 100 ft in the upland area (Adamski et al., 1995).

Soils and Erosion

The two most extensive soils in the watershed are the Enders-Nella-Mountainburg- Steprock association, which occurs in the Boston Mountains, and the Clarksville-Nixa- Noark association, which occurs in the Springfield Plateau. Together, these two soil associations cover about 76 percent of the land area in the Buffalo River watershed. There are 64 dominant taxonomic soil units mapped and a total of 167 mapping units in the watershed. This shows that the area within the watershed is highly complex and variable with regard to soil characteristics (Scott and Smith, 1994). Most soils contain significant amounts of coarse fragments (predominantly chert) on the surface and in the profile (NRCS, 1995).

Land slope data show that steep slopes are found on a large portion of the watershed (Table 4). Land slopes range from one percent or less in valley bottoms and upland flats to 60 percent on the sides of mountains. The hazard potential for erosion is moderate to very severe, depending on land cover and slope. Soils in pastures on steeper slopes are difficult to manage, and the use of farm equipment is restricted. Slopes over 15 percent should not be cleared for pasture (NRCS, 1995). Over 45% of the watershed occurs in slope category 7 to 14 degrees and almost 30% is in a slope category of greater than 14, indicating the ruggedness of the terrain (Scott and Hofer, 1995).

Unfortunately, over the 27-year period, the greatest loss of forest was in the two highest slope categories (Scott and Hofer, 1994). The acreage in pasture increased among all years in all slope categories during the 27-year period and the greatest increase in pasture was in the two highest slope categories where pastureland is not recommended. Figure 10 shows the distribution of the three slope categories throughout the watershed.

Fluvial Geomorphology

The long-term consequences of the destruction of riparian vegetation are now becoming evident in Ozark streams, including the Buffalo River. Several studies have found that Ozarks streams have excess gravel loads and an altered geomorphology due to land clearing nearly 100 years ago (Jacobson and Prim, 1997; Panfil and Jacobson, 2001). At the time of European settlement, beginning in the 1830's, streams deposited more gravel and less silt and clay, indicative of less energy dissipation in the valley bottom from decreased riparian vegetation. Lower order streams became depleted of gravel and this gravel was accumulating in the higher order streams. Before European settlement, streams were depositing a mixed sediment load of gravel bedload and silty overbank sediment (Jacobson and Primm, 1997). Observations of early explorers conspicuously lack descriptions of extensive gravel bars; observations of geologists working during the middle to late 1800's include descriptions of large quantities of gravel in stream banks and beds (Jacobson and Primm, 1997). Valley bottom reworking is believed to have occurred faster in the last 100 years than over the previous thousands of years (Albertson et al., 1995).

Probably the most destabilizing effect on Ozark stream channels during this period was caused by livestock grazing in valley bottoms that destroyed riparian vegetation (Jacobson and Primm, 1997). Destruction of riparian vegetation in small valleys continued into the 1900's, encouraging headward migration of channels and resulting in extension of the drainage network and accelerated release of gravel from storage in the small valleys (Jacobson and Primm, 1997). From 1960 to 1993, cultivated fields and croplands decreased, but cattle populations continued to increase. This increase in grazing density is likely maintaining runoff and sediment delivery to streams at rates higher than natural background rates (Jacobson and Primm, 1997).

Panfil and Jacobson (2001) demonstrated that the amount of gravel in Ozark streams is positively correlated with cleared riparian buffer zones and with increased cleared land in the drainage basin. The proportion of cobble and boulders is negatively associated with both increased gravel and cleared buffer zones. A strong positive correlation (R2 = 0.85) was found between the proportion of gravel in the thalweg and the proportion of cleared land in the drainage basin (Panfil and Jacobson, 2001) (Figure 48a and b). These results Panfil and Jacobson (2001) demonstrated that the amount of gravel in Ozark streams is positively correlated with cleared riparian buffer zones and with increased cleared land in the drainage basin. The proportion of cobble and boulders is negatively associated with both increased gravel and cleared buffer zones. A strong positive correlation (R2 = 0.85) was found between the proportion of gravel in the thalweg and the proportion of cleared land in the drainage basin (Panfil and Jacobson, 2001) (Figure 48a and b). These results

When riparian vegetation has been excessively cleared, a chain of disturbances begins that results in modified geomorphology which causes habitat loss and negative impacts to stream biota. Increased fine sediment causes substrate to become embedded. Increased embeddedness reduces pore space between gravel and cobble, which is important habitat for macroinvertebrates and small fish. Embeddedness also inhibits flow of oxygenated waters through the bed gravel.

More gravel in the system reduces the average particle size and decreases particle diversity in the streambed (Panfil and Jacobson, 2001). When coarse substrates are lost, the larger pore spaces they provide are also lost, filled in with smaller gravel. Fluxes of gravel into the stream also cause the stream to become shallower, filling in channels and reducing longitudinal roughness (Panfil and Jacobson, 2001). Habitat diversity decreases as more gravel, glide habitats increase and pool habitats disappear. This reduces living space for pool-dependent species. Shallow streams also may have greater daily and seasonal fluctuations in water temperature.

Loss of coarse woody debris inputs into the stream from riparian vegetation means fewer debris jams and snags, which create flow diversity and initiate scour that forms pool habitats. Increased storm flows cause more erosion and bank destabilization, causing stream banks to become a source of fine sediment and gravel into the stream. Stream bank erosion also leads to stream widening, reduction in channel sinuosity, and loss of canopy cover. This creates shallower, warmer habitats and lowers habitat diversity (Panfil and Jacobson, 2001).

Karst Groundwater:

This project, currently in the final stages of completion, focused on an area of suspected interbasin transfer and integrates groundwater tracer studies, geologic mapping, karst inventories, and water quality analyses to delineate and characterize the groundwater recharge area of Davis Creek (a major tributary to the Buffalo) and John Eddings Cave. The results will allow park managers to more effectively protect contributing karst basins and researchers to better interpret the results of aquatic resource investigations. The objectives of this study included 1.) map the surficial geology, 2.) inventory karst features (such as sinkholes, caves, solution conduits, losing stream reaches and springs), 3.) collect, measure, and analyze water quality in selected springs and streams, 4.) delineate groundwater recharge basins, and 5.) assess the biological community within John Eddings Cave.

Gravel Mining

Brown and Lyttle (1992) assessed the impacts of gravel mining on fish communities in Ozark streams. Three streams were selected, Crooked Creek, the Kings River, and the Illinois River. Study sites were located above, at, and below gravel mining operations. Impacts on fish community structure, habitat, biofilm accumulation, aquatic macroinvertebrates, and macrophytes were assessed. The results indicated that gravel mining significantly degrades the quality of Ozark stream ecosystems and that the effects of this are detectable even though these streams have a long history of anthropogenic disturbances. Alterations of physical habitat appear to more significantly influence the biotic community than limitations imposed on other resources (such as food supply), but these probably interact synergistically to limit some populations (Brown and Lyttle, 1992).

Brown and Lyttle (1992) found that the natural riffle pool sequence was altered by gravel mining. Pools located downstream from gravel mines tended to be longer and shallower than the upstream reference pools. The expected sequence of the spacing of riffles every 5 to 7 channel widths did not occur at disturbed sites but was found at all reference sites. Channel widths increased by an average of more than 10 meters at disturbed and downstream sites in all three rivers. The gravel mining process also resulted in the removal of woody debris and aquatic macrophytes at disturbed sites, decreasing channel stability and habitat diversity. Larger gravel particles form an effective armor plating on the smaller particles and alluvial deposits. When these larger particles are removed, as they are in gravel mining, the armoring is removed and exposed sediments are more easily transported. This process, in conjunction with channelization effects, causes increased sediment loading and turbidity.

Turbidity levels were not significantly different when gravel was not being harvested among the sites (Brown and Lyttle, 1992). However, turbidity was significantly higher at disturbed and downstream sites compared to reference sites while mining was in progress (Brown and Lyttle, 1992). Increased turbidity affects fish by reducing their feeding efficiency and tolerance for disease. Increased sediment loads affect the viability of fish eggs and fry. AG&FC found that on the Kings River, there was a 50% decrease in smallmouth bass downstream from gravel mines due to a 15-fold increase in turbidity (Femmer, 2002).

Brown and Lyttle (1992) documented several impacts upon fish communities from gravel mining. In all three streams, the number of fish per hectare was higher in upstream reference pools when compared to downstream and disturbed pools. Game fish in both biomass and in numbers per hectare were significantly higher in reference pools compared to disturbance and downstream pools. Silt sensitive species were consistently more abundant in reference pools and riffles. Logperch (Percina caprodes) and black redhorse (Moxostoma duquesnei) were absent from downstream pools. Silt sensitive species, including Northern hogsuckers (Hypentelium nigricans), greenside darters (Etheostoma blennioides) and the streamline chub (Erimystax dissimilis) were repressed in numbers downstream from the mine sites. Other species not considered silt sensitive were low in abundance downstream from mining sites. The yellow bullhead (Ameiurus natalis) in Crooked Creek and the Kings River, the spotted gar (Lepisosoteus oculatus) in the Kings River, and the redear sunfish (Lepomis microlophus) in the Illinois River were absent from mining sites. These fish may be mobile enough to avoid disturbed areas. The only species that benefited from gravel mining was the stoneroller minnow (Campostoma sp.). A wide and more shallow channel allowed greater light penetration and increased algal production, benefiting the grazing stoneroller. The impact of gravel mining on game fish species versus non-game fish is shown in Figure 53.

The overall result of gravel mining in the Ozarks is habitat degradation and reduction in the numbers of most fish species. Stream channels are altered, sedimentation rates and turbidity levels increase, downstream riffles become reduced and pools become more shallow. Riverbanks are destabilized and riparian zones are lost. This results in changes in the fish community which favor non-game fish more tolerant of disturbed conditions.

Source National Park Service, Water Resources Division


Adamski, J.C., J.C. Peterson, D.A. Freiwald, J.V. Davis, 1995. Environmental and - Hydrologic Setting of the Ozark Plateaus Study Unit, Arkansas, Kansas, Missouri, and Oklahoma, USGS, Water Resources investigation report: 94-4022, Little Rock, Arkansas.

Albertson, P.E., D. Mienert., and G. Butler, 1995, Geomorphic evaluation of Fort Leonard Wood: U.S. Army Corps of Engineers. Waterways Experiment Station, Technical Report GL-95-19.

Brown, A.V., and Lyttle, M.M., 1992, Impacts of gravel mining on Ozark steam ecosystems: Arkansas Cooperative Fish and Wildlife Research Unit, University of Arkansas , Fayetteville , Arkansas .

Femmer, Susanne. Instream gravel mining and related issues in southern Missouri . USGS Fact Sheet 012-02, February 2002.

Jacobson, R.B., and Primm, A.T., 1997, Historical Lad-Use Changes and Potential Effects on stream disturbance in the Ozark Plateaus, Missouri : United States Geological Survey Water-Supply Paper 2484.

McKenney, 1997. Formation and Maintenance of Hydraulic Habitat Units in Streams of the Ozark Plateaus, Missouri and Arkansas : Ph.D. Dissertation, Pennsylvania State University.

National Park Service (NPS), 1977. Final Master Plan, Buffalo National River , Arkansas : NPS 713-B Denver Service Center, Denver, Colorado.

Natural Resources Conservation Service, 1995. Buffalo River Tributaries, Watershed Plan Environmental Assessment: Natural Resources Conservation Service, Little Rock, Arkansas.

Panfil, M.S. and R.B. Jacobson, 2001. Relations among geology, physiography, land use, and stream-habitat conditions in the Buffalo and Current River systems, Missouri and Arkansas , USGS/BRD/BSR-2001-0005.

Scott, H.D. and K.R. Hofer, 1995. Spatial and temporal analysis of the morphological and land use characteristics of the Buffalo River Watershed, Arkansas Water Resources Center Publication number: MSC-170, University of Arkansas , Fayetteville , Arkansas.

Scott, H.D., and P.A. Smith., 1994. The prediction of sediment and nutrient transport in the Buffalo River watershed using a Geographic Information System: Arkansas Water Resources Research Center , University of Arkansas , Fayetteville , Arkansas.

A River Nestled in the Arkansas Ozarks
The Buffalo River comes as a surprise. How did a river surrounded by the progress of civilization escape impoundment, impairment, and change? To preserve the Buffalo as a free-flowing stream, Congress designated it a national river in 1972. Floating the Buffalo can give you a feeling of the wildness once haunting this country. The Buffalo nestles in the Arkansas Ozarks, which are bounded on the north, east, and south by the Missouri, Mississippi, and Arkansas rivers. To the west lies prairie.

Originating high in the Boston Mountains, over its course the Buffalo drops steadily to its confluence with the White River. The gradient is steep and the water is faster along the upper river, leveling and slowing as the river runs its course. In some places, long quiet pools between rapids obscure its vertical travels. The land's wildness and isolation are dramatized by a side trip into any number of hollows flanking the river. One wonders if some have been frequented since they served as guerrilla hideouts during the Civil War.

Many prehistoric and historic cultural sites are located throughout the park, some dating back more than 10,000 years. These range from bluff shelters once occupied by Archaic Indians to the cabins built by early settlers to existing homes of Ozark farmers still living in harmony with the land.

    Four areas are listed on the National Register of Historic Places.,
  • Boxley Valley,

  • the Parker-Hickman Farmstead at Erbie,

  • the Civilian Conservation Corps-built structures at Buffalo Point, and

  • the Rush mining district.

The meaning of the Buffalo River today is not difficult to discern. It is reflected in the faces of people accepting the river's recreational challenges. It rises in the spirits of people immersed in this landscape's beauty. It finds its measure among the families who celebrate, with periodic riverside reunions, their multiple generations living in the area. Here are exhilaration and enthusiasm, relaxation and recreation. Here these merge with living tradition as thoroughly as the wild and free-running Buffalo River merges with its ancient Ozarks setting.

Scenic Landscape Formations
Buffalo River bluffs reach as high as 500 feet above the river. They are the Ozarks' highest. These stacks of ancient seabeds have been relentlessly sculpted by erosion. Their towering multi-colored cliffs sharply accent the surrounding wild mountain beauty. The park's geology, with its numerous caves, sinkholes, waterfalls, springs, and interesting rock formations, typifies the Arkansas Ozarks.

park maps subheading

The General park map handed out at the visitor center is available on the park's map webpage.

For information about topographic maps, geologic maps, and geologic data sets, please see the geologic maps page.

photo album subheading

A geology photo album has not been prepared for this park.

For information on other photo collections featuring National Park geology, please see the Image Sources page.

books, videos, cds subheading

Currently, we do not have a listing for a park-specific geoscience book. The park's geology may be described in regional or state geology texts.

Please visit the Geology Books and Media webpage for additional sources such as text books, theme books, CD ROMs, and technical reports.

Parks and Plates: The Geology of Our National Parks, Monuments & Seashores.
Lillie, Robert J., 2005.
W.W. Norton and Company.
ISBN 0-393-92407-6
9" x 10.75", paperback, 550 pages, full color throughout

The spectacular geology in our national parks provides the answers to many questions about the Earth. The answers can be appreciated through plate tectonics, an exciting way to understand the ongoing natural processes that sculpt our landscape. Parks and Plates is a visual and scientific voyage of discovery!

Ordering from your National Park Cooperative Associations' bookstores helps to support programs in the parks. Please visit the bookstore locator for park books and much more.

geologic research subheading


For information about permits that are required for conducting geologic research activities in National Parks, see the Permits Information page.

The NPS maintains a searchable data base of research needs that have been identified by parks.

A bibliography of geologic references is being prepared for each park through the Geologic Resources Evaluation Program (GRE). Please see the GRE website for more information and contacts.

selected links subheading

NPS Geology and Soils Partners

NRCS logoAssociation of American State Geologists
NRCS logoGeological Society of America
NRCS logoNatural Resource Conservation Service - Soils
USGS logo U.S. Geological Survey

teacher feature subheading

Currently, we do not have a listing for any park-specific geology education programs or activities.

General information about the park's education and intrepretive programs is available on the park's education webpage.

For resources and information on teaching geology using National Park examples, see the Students & Teachers pages.
updated on 01/04/2005  I   http://nature.nps.gov/geology/parks/buff/index.cfm   I  Email: Webmaster
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