Stream Management in the Piedmont and Mountains

Are you protecting the streams on your farm?

North Carolina's 37,000 miles of streams and rivers and the floodplains and upland areas adjacent to these waters possess great economic, social, cultural, and environmental value. These corridors contain complex ecosystems that encompass the land, plants, animals, and stream networks. Some common features of river corridors are shown in Figure 1.

Figure 1

 Rivers and streams perform a number of important functions, including carrying water and sediment,storing water in wetlands and floodplains, and providing habitat for aquatic and terrestrial plants and animals. For these and other reasons, protecting streams is important. But the quality of many streams and rivers is degraded by pollutant discharges, contaminated runoff, or streambank erosion. Common pollutants in North Carolina streams and rivers include sediment, bacteria, and nutrients. Some home and farm practices pollute rivers and streams and may be detrimental to wildlife habitat and populations. All farmers should integrate environmental stewardship into their production practices. Good streamside management can protect stream quality and enhance fish and wildlife populations.

Natural stream channels in wide valleys are rarely straight. Over many years, streams meander from one side of a valley to the other and, in the process, create floodplains (Figure 2). Stable streams maintain their shape by slowly eroding the outside of a meander bend while also depositing sediment on the inside bend. Unaltered streams located in large, flat floodplains have more meanders than steep streams without floodplains. Whatever the channel form, most unaltered streams have alternating, regularly spaced, deep and shallow areas called pools and riffles (Figure 3).

Figure 2

Figure 3 (A=profile view; B=plan view)

Most streams in the floodplains of North Carolina have been straightened—or channelized—at some point to promote agriculture and development. Channelization can cause a stream reach to be unstable. The effects of channelization are discussed in more detail under Question 6.

How can we help?
This worksheet is intended to help landowners and farmers identify potential problems with the streams on their property and select management options that will better protect these important water resources. While many of the questions are relevant to all North Carolina landowners, several are specific to gravel-bed streams found predominately in the piedmont and mountains.

Each of the sections in this fact sheet addresses a different topic. Accompanying each topic is a question. A glossary of terms that may be unfamiliar is at the end of the fact sheet. Your answers will help you to see where your farming practices may harming the stream corridors.

• If you answer a or b, you have few problems.
• If you answer c or d, some of your agricultural practices may be degrading water resources.
• If you answer c or d, you will want to consider making changes, both to farm profitably and to protect the streams that flow through your property.

The goal of the North Carolina Farm*A*Syst program is to help you protect the natural resources that all North Carolina residents depend on, while maintaining viable agricultural production practices.

If you would like further help in assessing conditions on your farm, please visit your nearest Cooperative Extension Service Center, your local Natural Resources Conservation Service office, or your North Carolina Soil and Water Conservation District office.

1. How much and what kind of vegetation grows along the stream corridors on your farm?

The vegetated area along the edges of a stream is called the riparian buffer (Figure 4). These plants determine the type and quantity of debris (leaves and wood) that falls into the stream and provides food for aquatic animals. A stream that is bordered by diverse trees and shrubs is likely to provide better food for insects and fish than a stream bordered by only grass. Generally, vegetation that falls into the stream does not move very far away, so the food benefits are highly localized. Older forests that contain mature trees and underbrush provide the greatest variety of food for aquatic insects. Streamside vegetation also determines how much sunlight reaches the stream, which in turn affects the temperature of the water. Lower water temperature frequently provides a more favorable habitat for fish species such as trout. The amount of light reaching a stream depends on both the density of buffer vegetation and the size of the stream. For smaller streams, the riparian canopy of trees can almost entirely block sunlight from the water.

Vegetation slows the flow of water and reduces erosion of the banks. The root systems of mature trees like willows, dogwoods, and alders provide tremendous support for bank soils. Overall, streams with a mature, diverse riparian buffer are the most stable over time. Landowners gain a stable stream corridor that does not rapidly erode cropland or pastureland; cover and food for wildlife such as quail, wild turkey, and deer; and improved habitats for fish.

1. Circle the answer that best describes the woody vegetation along your stream.

a. Plenty of overhanging vegetation (71-100 percent).

b. Some overhanging vegetation (41-70 percent).

c. Little overhanging vegetation (11-40 percent).

d. Little to no overhanging vegetation (0-10 percent).

2. How wide are your streamside buffers and what kind of plants grow there?

As discussed above, riparian buffers are important for wildlife habitat, water quality, and stream stability. Streamside vegetation also can reduce the amount of nitrogen and phosphorus flowing into streams from nearby agricultural fields and can filter out sediment and other pollutants running off the land during storms.

The width of a buffer and the type of vegetation growing there will depend on many factors, including slope, soil type, and purpose of the buffer. However, a buffer with mixed vegetative types is probably the best at controlling different types of pollutants and protecting stream quality. Buffers should be at least 50 feet wide. Trees should be planted next to the stream and extend out at least 25 feet. Another 25 feet of grass should be planted beyond the trees.

2. Circle the answer that best describes the condition of the buffers next to the streams that flow through your property.

a. At least 25 feet of trees or shrubs and 25 feet of grass.

b. At least 25 feet of trees.

c. Between 5 and 25 feet of grass, shrubs, or trees.

d. Less than 5 feet of grass and no trees or shrubs.

3. How high are the streambanks on your land?

Bank height and steepness are the most important indicators of streambank stability. When streambanks are too high and steep, soil erodes from the bank. Bank height is related to factors such as bank slope, soil types, vegetation cover, and location along the reach (streambanks along the outside of a curve naturally erode more than those on the inside of the curve). However, once a critical bank height is reached, erosion likely will occur regardless of the other factors. If this is an issue on your farm, you will want to consult a professional listed at the end of this publication.

3. Circle the answer that best describes the slope of the streambank.

a. Streambanks are less than 5 feet high.

b. Streambanks are between 5 and 8 feet high.

c. Streambanks are between 8 and 12 feet high.

d. Streambanks are greater than 12 feet high.

4. What is the condition of the streambed?

Scientists often describe the amount of sediment deposited on the bottom of a stream channel as percent embeddedness—the degree to which fine sediments such as sand, silt, and clay fill the spaces between rocks on the bottom of a stream.

Fish and insects can cope with some embeddedness of a stream, but they cannot withstand any increase above the natural levels without losses. Excess sediment can fill pools and eliminate important habitats for fish. It can also threaten aquatic insect communities because particles of sediment may obscure sources of food, hiding places, and nesting sites. Most aquatic insects simply drift with the current out of areas affected by sediment. However, this reduces the food source for the fish that remain.

Fish reproduction may decline with an increase in fine sediment or embeddedness. If sediment alters spawning habitat (filling in pools and riffles or covering a gravel bed), fish may be unable to lay eggs. If eggs are produced, they may be in jeopardy during the incubation period. Eggs may suffocate and be poisoned by their own metabolic waste. If eggs do hatch into fry, the young may be less likely to survive in these less-than-optimum conditions.

Landowners can keep excess sediment out of their streams through a variety of erosion and sediment control measures, including runoff control, vegetative cover, buffer zones, and streambank stabilization. Runoff control intercepts and slows runoff through approaches such as diversions, level spreaders, grass waterways, and strip cropping. Vegetative cover provides a root system that holds the soil in place during storms. Vegetation should be planted on all bare soil immediately after it is dug. The benefits of buffer zones and streambank stabilization are discussed above.

4. Circle the answer that best describes the amount of silt that covers the rocks in the bottom of the stream.

a. Less than 25 percent of bottom covered by silt; it mostly consists of exposed gravel or rock.

b. 26-50 percent of bottom covered by silt; there is some exposed gravel or rock.

c. 51-75 percent of bottom covered by silt; there is little gravel or rock.

d. More than 75 percent of bottom covered by silt; there is no gravel or rock.

5. What channel features do you observe in the streams on your land?

A diversity of deep pools, fast-moving riffles, shaded areas, and clean gravel or cobble bottoms provides optimum habitat for fish and other aquatic organisms (see Figure 3). Tree roots and woody debris also create important habitat for aquatic insects and fish. Pools are found in the outside of bends at a spacing of five to seven times the channel width. Stable streambanks help maintain the natural, stable shape of the stream.

Management practices that reduce streambank erosion and sedimentation and protect riparian vegetation can help maintain the critical stream channel features mentioned above. If you notice that streams on your land lack some of these features, see the previous questions for information.

5. Circle the answer that best describes the pools and riffles in the stream.

a. Regular spacing of riffles and pools. (Riffles are steep and shallow, pools are flat and deep).

b. Regular spacing of riffles and pools. (Riffles are steep and shallow, pools are flat but shallow with an abundance of silt).

c. Irregular spacing of riffles and pools. (Most of the stream is riffle with few pools).

d. The entire stream is a riffle with no pools.

6. Have your streams been channelized?

Naturally stable floodplain stream channels are typically sinuous with varying channel depths and streambanks low enough to allow large storm flows to overflow onto the floodplain every one to two years. The natural meandering and varying channel depths dissipate the energy of the water and reduce streambank erosion. Floodplains also dissipate water energy during high flows, spreading shallow water over a wide area.

Many streams in North Carolina have been straightened and dredged for agriculture, development, and flood control. Straight streams have a steeper gradient than meandering streams which often results in channel incision. Incision is an erosional process that lowers the streambed elevation until it reaches bedrock or other resistant materials. Incision increases streambank heights and disconnects the stream from the original floodplain. With more water in the channel, a steeper slope, and high banks, the stream has more power to erode the streambanks. Over time, the stream erodes the banks, forming a new floodplain at a lower elevation. Figure 5 shows a comparison between natural streams and channelized streams.

Figure 5: Comparison of naturally formed stream to channelized stream.

6. Circle the answer that best describes the straightness of the stream.

a. Stream has not been channelized or dredged.

b. Stream was channelized in the past or dredged in some areas; channel is currently stable.

c. Stream was channelized or dredged in the past; channel is mostly stable.

d. Stream has been extensively channelized or dredged; channel is mostly unstable.

7. Do you allow livestock access to streams?

Cattle, horses, and other livestock can damage streambanks and channels and degrade water quality if they are allowed continuous access to streams. Livestock can trample and destroy vegetation, damage the banks, and deposit animal wastes that cause bacteria and nutrient contamination of the water.

If stream crossings are necessary, they should be constructed in riffle areas and stabilized with rock or other materials (See Figure 6). When possible, fence livestock out of the stream and give them alternate sources of water. Your local NRCS, Soil and Water Conservation District, or Cooperative Extension Service representative can help you develop a livestock exclusion plan.

Figure 6: Appropriate place in stream for cattle to cross.

7. Circle the answer that best describes livestock access to the stream.

a. No access.

b. Only at properly designed stream-crossing sites.

c. Continual access. They cause moderate bank damage.

d. Continual access. They cause severe bank damage.

8. Are the streambanks eroding?

Determining why streambanks are eroding faster is the first step in solving the problem. When a stream is straightened or widened, streambank erosion increases. In addition, damaging or removing streamside vegetation can dramatically worsen bank erosion. This is often the case when livestock have access to the stream.

Many of the traditional methods for dealing with streambank erosion have been expensive to install and maintain. Solutions such as placing riprap (crushed quarry stone, usually larger than 8 inches in diameter), old cars, or concrete blocks in the stream may solve the problem, but at the expense of the aquatic habitat and natural beauty. In addition, many of these traditional approaches cause further erosion downstream. But there are some promising developments in streambank stabilization and stream restoration. Natural channel design principles look to nature for the blueprint to restore a stream to a stable, self-sustaining form. Contact the N.C. Stream Restoration Institute for more information.

8. Circle the answer that best describes the streambank conditions.

a. No evidence of erosion. Banks are covered with grass or forest vegetation.

b. Banks are slumping in a few spots. Most of banks are covered with vegetation.

c. Some erosion occurs during large flows. Many areas are without vegetation.

d. Severe erosion. Mostly no vegetation.

9. How have you set up drainpipe outlets to streams?

Streambanks also can be eroded by runoff discharged directly into streams through drainage tile outlets.

If underground drain lines feed into the stream, the outlets should be located in the riparian buffer area. Pipes that discharge directly into the stream often cause erosion of the streambank and channel bottom. A riparian buffer and tile outlet protection will slow the water exiting the drain line and reduce the amount of nutrients and sediment entering the stream.

9. Circle the answer that best describes discharge from pipes or outlets in or near the stream.

a. No erosion around tile outlets. Pipes do not discharge directly into streams, but into buffer area.

b. No erosion around tile outlets. Pipes discharge directly into streams.

c. Some erosion around tile outlets. Pipes discharge directly into streams.

d. Severe erosion around tile outlets and in stream bottom. Pipes discharge directly into streams.

10. Does runoff from your farm cause streambanks to erode?

Runoff from surrounding land that enters a stream through ditches, channels, or grass-lined waterways may erode streambanks or channel bottoms.

If erosion occurs following rainfalls, runoff water should be diverted to a level spreader or berm. Level spreaders or berms spread the flow out over the riparian buffer. This slows the water, reducing its erosive energy and, therefore, improves the performance of the buffer.

10. Circle the answer that best describes surface flow into the stream.

a. No bank damage where concentrated runoff enters stream. Runoff spreads through buffer before entering stream.

b. No bank damage where concentrated runoff enters stream. Banks protected by stable inlets.

c. Bank damaged by entry of surface water. Protection at entry points not adequate to prevent damage.

d. Severe bank damage caused by entry of surface water.

11. Do you inspect your stream corridors and maintain them as needed?

Streams can be expected to change their shape and size slightly over time, especially following large storms. Periodic inspection will help determine if streambanks are eroding or the channel bottom is shifting more than normal.

In addition, you should maintain your stream by removing large debris jams and planting trees, shrubs, or grass where riparian vegetation is lacking. Never remove trees or shrubs from streambanks.

11. Circle the answer that best describes your stream inspection and maintenance practices.

a. I inspect all streams after major storms for signs of damage to banks, outlets, and stream bottom.

b. I inspect streams each spring and fall for signs of erosion.

c. I inspect streams once each year for signs of erosion.

d. I never inspect the streams on my land.

Contacts and References

• NC Stream Restoration Institute
  NC State University Box 7637
  Raleigh, NC 27695-7637
  Phone: (919) 515-8245
  Email: will_harman@ncsu.edu
  http://www5.bae.ncsu.edu/programs/extension/wqg/sri/
• Natural Resources Conservation Service (NRCS)
  4405 Bland Road, Suite 205
  Raleigh, NC 27609
  Phone: (919) 873-2126
• NC Wetlands Restoration Program
  Department of Environment and Natural Resources
  Division of Water Quality
  P.O. Box 29535
  Raleigh, NC 27626-0535
  http://h2o.enr.state.nc.us
• NC Wildlife Resources Commission
  512 Salisbury Street
  Raleigh, NC 27604-1188
  Phone: (919) 733-3391
  http://www.state.nc.us/Wildlife/
• US Fish and Wildlife Service
  P.O. Box 33726
  Raleigh, NC 27636-3726
  Phone: (919) 856-4520

Glossary

Channel: The pathway of a stream through which water flows.

Channel alteration or channelizing: Changing the flow path of a stream, usually to straighten it.

Drainageway: Waterway, generally vegetated, that carries runoff or shallow surface water.

Floodplain: A flat valley bottom that is formed by a river over time. Active floodplains typically are flooded less than every two years.

Groundwater: Water beneath the earth's surface that supplies wells and springs.

Meander: A smooth turn made by the stream.

Meander scrolls: A former meander through which the stream no longer flows.

Oxbow Lake: A cut-off meander that initially holds water.

Pool: Located on the outside of a meander bend or the bottom of a step, pools are deep areas in the stream created by scour. Pools generally contain fine-grained bed materials, such as sand and silt.

Riffle: Gravel size or larger bed sediment where the stream is shallow and swift at low flows. Riffles are produced during high flows by the accumulation of large bed materials.

Riprap: Quarry rock, usually 8 to 10 inches in diameter or larger, used to stabilize slopes.

Runoff: Rainwater that "runs off" over the land during a storm.

Slumping: A downward movement of the slope of a stream or ditch bank that leaves exposed soil behind.

Stream: A natural watercourse that carries water for all or part of the year.

Stream crossing: A structure for livestock and machinery to cross a stream. It should be constructed at the bottom of the stream or ditch and have an erosion-resistant surface. All water flows over the structure, and livestock and machinery must cross through the water.

Surface water: Water at the earth's surface, such as ponds, lakes, streams, or ditches.

Thalweg: The deepest part of a channel. Also considered to be the main channel.

Tile outlet protection: The use of an erosion-resistant material, such as rock riprap, on top of a filter cloth, to protect the stream or ditch bank area where water exits a tile drain.

Wetland: Landscape characterized by shallow standing water all or most of the year, with vegetation rising above the water level.

Related Publications

• Federal Interagency Stream Restoration Working Group. 1999. Stream Corridor Restoration: Principles, Processes, and Practices. Federal Interagency Stream Restoration Working Group. Washington, DC.
• Gilliam, J.W., D.L. Osmond, R.O. Evans. 1997. Selected Agricultural Best Management Practices to Control Nitrogen in the Neuse. North Carolina Agricultural Research Bulletin 113. Raleigh, NC.
• Harman, W.A. and Jennings, G.D. 1999. Natural Stream Processes. AG-590-1. NC Cooperative Extension Service. Raleigh, NC.
• Harman, W.A. and Jennings, G.D. 1999. Application of the Rosgen Stream Classification System to North Carolina. AG-590-2. NC Cooperative Extension Service. Raleigh, NC.
• Pilot View RC&D. 1999. Soil in Our Streams. Stream Notes. Volume 1, Number 1. Pilot View RC&D. Winston-Salem, NC.
• Pilot View RC&D. 1999. Streambank Erosion. Stream Notes. Volume 1, Number 2. Pilot View RC&D. Winston-Salem, NC.
• Pilot View RC&D. 1999. Riparian Buffers. Stream Notes. Volume 1, Number 3. Pilot View RC&D. Winston-Salem, NC.
• Osmond, D.L. and J.W. Gilliam. 1999. Agricultural Riparian Buffers. AG-439-38. North Carolina Cooperative Extension Service. Raleigh, NC.

To Find Your State Division of Water Quality Location

• ¹Interchange Building, 59 Woodfin Place, Asheville, NC 28801; 828-251-6208

• ²505 Waughtown St., Winston-Salem, NC 27107; 336-896-7007
• ³3800 Barrett Drive, Suite 101, Raleigh, NC 27609; 919-571-4700
• ⁴1424 Carolina Avenue, Washington, NC 27889; 252-946-6481
• ⁵919 North Main Street, Mooresville, NC 28115; 704-663-1699
• ⁶Wachovia Building, Suite 714, Fayetteville, NC 28301; 910-486-1541
• ⁷127 Cardinal Drive Extension, Wilmington, NC 28405-3845; 910-395-3900

College of Agriculture & Life Sciences . NC State University
School of Agriculture . NC A&T State University

Prepared by

William A. Harman
Water Quality Extension Specialist

Deanna L. Osmond
Soil Science Extension Specialist

Gregory D. Jennings
Associate Program Leader

J. Richard Everhart
District Conservationist,
United States Department of Agriculture -
Natural Resources Conservation Service

Janet Young
Layout and Design Specialist

The concept for these materials was adapted from materials produced by the National Farm*A*Syst Program, University of Wisconsin, Madison, WI.

North Carolina's Farm*A*Syst and Home*A*Syst Program is coordinated by Deanna L. Osmond, North Carolina State University. Technical editing was provided by Judith A. Gale.

This project has been funded with Section 319 grant monies from the U.S. Environmental Protection Agency through the N.C. Department of Environment, and Natural Resources, Division of Water Quality.

Published by

NORTH CAROLINA COOPERATIVE EXTENSION SERVICE

Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age, or disability. North Carolina State University, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.

AG-566-09
E00-38855

This document was updated on 9/13/00 by Janet Young.