Protecting Riparian Areas: Farmland Management Strategies

PROTECTING RIPARIAN AREAS:
FARMLAND MANAGEMENT
STRATEGIES
SOIL SYSTEMS GUIDE

Abstract: This publication is designed to help farmers, watershed managers, and environmentalists understand what
healthy riparian areas look like, how they operate, and why they are important for the environment and society. It also
provides information on the costs and benefits of riparian management and discusses how watershed residents can work
together to protect this vital resource. Tables included in the publication are designed to help you evaluate riparian
protection strategies from the perspective of your local environment, surrounding land use practices, and land management
objectives.

By Barbara C. Bellows
NCAT Agriculture Specialist
March 2003

Introduction
Introduction
Riparian areas include streams, streambanks, and wetlands adjacent to streams. These areas have
a water table high enough to interact with plant roots and affect their growth throughout most of the
year. Plant species that thrive in riparian areas are adapted to wet and flooded conditions. They are
also adapted to regrow root systems in sedi-
ments deposited through soil erosion
(Schneider, 1998).
Healthy riparian areas are critically im-
portant ecological zones. They provide:
• Water quality protection
• Structural support for streambanks
• Water capture and storage
• Flood control
• Stabilization of water flow in streams
and rivers
• Habitat for aquatic and terrestrial wild-
life
• Aesthetic and recreational benefits
Photo by USDA NRCS
Unfortunately, various land use prac-
tices have degraded riparian areas, result-
ing in impaired environmental conditions,
decreased agronomic production, and a multiplicity of social costs. Both agricultural and non-agricul-
tural land use practices are responsible for the degradation of riparian areas. These degrading land
use practices include:

ATTRA is the national sustainable agriculture information service operated by the National Center for
Appropriate Technology, through a grant from the Rural Business-Cooperative Service, U.S. Department
of Agriculture. These organizations do not recommend or endorse products, companies, or individuals.
NCAT has offices in Fayetteville, Arkansas (P.O. Box 3657, Fayetteville, AR 72702), Butte, Montana,
and Davis, California.

Table of Contents

Introduction ................................................................................ 1
Upland Land Management and Riparian Health ............................... 3
What do Riparian Areas Look Like?................................................ 5
Water and Sediment Capture by Riparian Areas............................... 6
Table 1. Vegetation Indicators for Riparian Areas........................ 8
Water Decontamination by Riparian Soils ....................................... 9
Table 2. Soil Indicators for Riparian Areas ............................... 10
Riparian Areas and Habitat Preservation ....................................... 11
Table 3. Streambank and Channel Indicators............................ 12
Land Management Practices to Protect Riparian Areas ................... 13
Table 4. Indicators of Aquatic and Riparian Wildlife ................. 14
Community Watershed Collaboration to Protect Riparian Areas ...... 16
Summary .................................................................................. 17
References ................................................................................ 17
Appendix 1: Impacts of Local Ecology on Riparian ........................
Characteristics................................................................... 22
Table A.1. Effect of Stream Order on Natural Riparian ..................
Table A.2. Effect of Rainfall and Temperature on Riparian..............
Appendix 2: Guidelines for Riparian Area Revegetation ............. 27
Appendix 3: Limited Ability of Riparian Areas to Control Phosphorus
Movement into Streams...................................................... 29
Appendix 4: Recommended Buffer Widths ............................... 30
Appendix 5: Economic Costs and Benefits of Riparian Buffer ..........
Protection ......................................................................... 32
Table A.3. Incentive Programs for Riparian Protection .............. 34

PAGE 2 //PROTECTING RIPARIAN AREAS: FARMLAND MANAGEMENT STRATEGIES

• Artificial stream widening and straightening Water moves across the landscape in two
• Road and building construction close to ways: as groundwater flow and as runoff. Sub-
streams surface or groundwater flow is water that has
soaked into the soil and travels underground
• Replacement of wooded or grassy areas with
through pores in the soil. Runoff is water that
roads, houses, and parking lots resulting in
moves over the surface of the soil. When
increased runoff into streams
groundwater or runoff water moves, it absorbs
• Unrestricted grazing or loitering of livestock nutrients or contaminants and transports them
in or near streams into riparian areas and potentially into streams.
• Crop production activities including plowing, Runoff water can also transport eroded soil par-
planting, and fertilizer, manure, and pesticide ticles.
applications close to streams Groundwater flow . In most undisturbed
watersheds, a majority of the water flows into
This publication is designed to assist farm- riparian areas and streams as groundwater
ers, ranchers, watershed managers, homeowners, rather than as runoff. As rain falls or snow
and community members in understanding the melts, leaves and other plant residues on the soil
importance of riparian areas and guide them in surface catch this water. Pores created by grow-
implementing land management practices to im- ing plants, decaying plant roots, and animal
prove riparian health. Tables included provide burrows help the water seep into the soil (Cohen,
tools to monitor the conditions of riparian areas 1997). Once it seeps into the soil, the resulting
during land restoration processes. groundwater moves relatively slowly under-
ground through soil particles until it reaches ri-
parian areas and associated streams.
Attached appendices provide detailed infor-
mation on subjects addressed in this publi-
cation. Above ground vegetation
traps sediment and
pollutants
Fertilizer and
pesticide residue

Land
Upland Land Flood
water level

Management and Stream
water level

Riparian Health Runoff reaches
stream carrying little
sediment, pesticide
and fertilizer residue,
Residue from making it healthier for
Water flows from upland areas through ri- fertilizer and plant and
pesticides are
parian areas and eventually into streams. trapped by
animal
life
Healthy riparian areas are able to absorb, hold, root systems

and use much of the water that flows off from
healthy upland areas. Healthy riparian areas Healthy streambank vegetation
are also able to chemically and biologically bind Plants in riparian areas filter ground and surface
or detoxify many contaminants contained in water moving into streams.
this water. However, if upland areas are de-
graded or covered with roads, parking lots, and (from Huel, 1998. ©Agriculture and Agri-Food Canada)

rooftops that do not allow the water to seep into
the soil, even the healthiest riparian area will Runoff is favored when rain falls faster than
be unable to absorb and filter large volumes of
the ground can absorb it. Water cannot be effec-
water, nutrients, and contaminants flowing
tively absorbed when soils:
through it. Therefore, the first step in riparian
• Are compacted at the surface
protection is ensuring that land management
practices across the watershed conserve soil and • Are bare, so that the impact of rain drops on
water resources. the soil forms a surface crust

//PROTECTING RIPARIAN AREAS: FARMLAND MANAGEMENT STRATEGIES PAGE 3

• Have pores that have become plugged by water and groundwater can also absorb nutri-
eroded sediments ents or become contaminated with pesticides or
• Have a clay texture that does not allow for pathogens in the soil. Streams are polluted when
rapid water movement into the soil contaminated water is able to move directly into
them.
• Are hydrophobic or have a surface crust,
typical of many arid or semi-arid soils (Fed- erosion
Impact of runoff and erosion on ripar- ripar-
eral Interagency Stream Restoration Working ian areas. Under healthy watershed conditions
Group, 2001). water infiltration across the landscape results
Runoff is also heavy when the soil does not in minimal runoff and erosion reaching ripar-
have the capacity to hold additional rainwater ian areas. Healthy riparian areas have a dense
or snowmelt entering the soil. This
occurs when:
• Soils have been replaced by im-
permeable surfaces such as
roads, parking lots, or rooftops
and insufficient natural or arti-
ficial wetlands are present to
capture water not able to be ab-
sorbed by soil
• Soils are rocky or have an impen-
etrable stony layer close to the
surface
• Soils are thin because the topsoil
has been eroded off
• Soils have a compacted layer of
“pan” within their profile that
Runoff from poorly vegetated areas carries eroded
acts as a barrier to downward
sediments into streams
water movement
• Groundwater levels are high
• Rain keeps falling on soils that
are already saturated growth of vegetation that catches any eroded
sediment and prevents it from entering streams.
They also have a diversity of plants that facilitate
water infiltration and take up many nutrients car-
Stream flashing ried into riparian areas by runoff and groundwa-
ter. Riparian areas also have a unique soil envi-
When runoff is heavy, such as following an ronment that provides favorable conditions for
intense storm or a rapid snowmelt, stream the chemical and biological degradation of many
levels can rise rapidly, often to flood stage. soil contaminants.
This rise in water levels is often very short However, when upland watershed condi-
term, lasting only a day or two, after which tions are degraded, heavy runoff can flow over
water levels decrease dramatically. The rapid or through riparian plants and move directly
rise and fall of water levels caused by runoff into river channels. Severe erosion in upland
is referred to as stream flashing. areas can degrade riparian areas by burying
plants under sediments. Fine sediments brought
in by erosion can degrade stream habitat by fill-
water.
Contaminant movement by water. Run- ing in stream pools, altering the shape of stream
off water flowing over the soil surface can pick channels, and covering rocky stream bottoms,
up and erode soil sediments. These sediments thereby eliminating important food producing,
may carry nutrients, pathogens, pesticides, and shelter and spawning areas (Wohl and Caline,
other contaminants, depending on the land-use 1996). Runoff and erosion also bring in seeds of
practices in the area they came from. Both runoff non-native or non-riparian plant species. Inva-


sive and non water-loving plant species can re- • A thick growth of vegetation, representing
duce habitat for native species and lower the wa- a diversity of grasses, forbs, shrubs, and trees,
ter table by crowding out more functional and covers the streambanks and provides shade
palatable riparian species. They can also create a over the stream
fire risk by increasing fuel loads (Allen et al, 2000). • Except where streams cut through rocky ter-
As runoff and erosion from upland areas con- rain, land surrounding streambanks re-
tinue to destroy the integrity of riparian areas, mains wet throughout most of the year
streamside areas loose their ability to buffer and
• Streambanks are more vertical than flat-
protect streams, resulting in damage to aquatic
tened out
habitat, increased costs for treating drinking wa-
ter, and loss of aesthetic appeal. • Streamflow levels vary only moderately
throughout the year
Soil and water conservation practices.
Water infiltration is enhanced by land-use prac- • Stream water is relatively clear but contains
tices that provide coverage of the soil surface leaves, twigs, or logs from streambanks that
with vegetation or residues throughout the year. create pools and other habitat for fish and
Conservation tillage, contour farming, cover other aquatic organisms
cropping, agroforestry, and rotational grazing • A diversity of fish, aquatic life, mammals,
are all practices that protect soil quality while and birds live in and around riparian areas
promoting water flow into the soil. For more
information on these soil and water conserva-
Appendix 1 describes regional differences in
tion practices, please see the following ATTRA
the structures and functions of riparian areas.
publications:
Sustainable Soil Management
Conservation Tillage Degraded riparian areas. In contrast, de-
graded riparian areas have some or all of the
Pursuing Conservation Tillage for Organic Crop
following characteristics:
Production
• Patchy or scrubby plant growth with bare
Rye as a Cover Crop ground showing in many places
Protecting Water Quality on Organic Farms • Vegetation dominated by upland plants in-
cluding noxious weeds
Sustainable Pasture Management
• Soil that is compacted, shows rills or gullies,
Rotational Grazing or has bare trails and pathways along the
Nutrient Cycling in Pastures streambanks
• Streambanks that are eroded, severely un-
dercut, or sloughing
What do Riparian Areas • Streams that flood regularly in the spring
and become dry during the summer
Like?
Look Like? • Streamwater that is muddy or murky and
may contain toxic levels of various nutrients
or contaminants
Healthy riparian areas. Characteristics of
• Few mammals or birds living or feeding in
healthy riparian areas differ across the country
the area
and across the landscape. In mountainous or
hilly areas, streams run through rocky gorges • Limited numbers and diversity of fish and
with scattered trees growing out of the thin soil. other aquatic species
In prairie landscapes, streams flow through These characteristics of degraded riparian
thick, silty soil, with banks covered by reeds, areas reflect their inability to protect water qual-
sedges, and willows. Despite these local differ- ity, stabilize water quantity, and provide criti-
ences, healthy riparian areas have certain simi- cal habitat for both land animals and aquatic
larities: species.


Water and Sediment Plants in the first band are water-loving and
have deep, strong roots that stabilize streambanks
against erosion (Clark, 1998). Plants in the sec-
Capture by Riparian ond and third bands catch water and facilitate its
absorption. They also take up nutrients trans-
Areas ported into the area by runoff and groundwater
and provide habitat for terrestrial animals. If land
Riparian areas protect water quality by cap- management practices reduce the riparian zones
turing, storing, and treating water that flows
to only one or two of these bands, some or all of
through their soils. A thick growth of diverse
the environmental and habitat benefits of these
vegetation, plant residues covering the soil sur-
areas will be lost. The first zone is both the most
face, and porous, non-compacted soil facilitate
ecologically important and requires the greatest
water capture. High streambanks with high
protection against degradation.
water tables provide water storage capacity.
Vigorously growing plants take up nutrients
transported into riparian areas, while active popu-
lations of both aerobic and anaerobic soil organ-
isms degrade many contaminants that flow into
these areas. Chemicals in soil minerals and soil
organic matter also capture or facilitate biologi-
cal detoxification of contaminants. Understand-
ing these components of healthy riparian areas

Photo by USDA NRCS
can help guide land management practices that
protect riparian areas and water quality.
Structure of riparian vegetation. Healthy
riparian vegetation captures water and facilitates
water infiltration into the soil. Riparian areas that Trees, brush, and grasses protect
include a diversity of plant species are most ef- streambanks against erosion and water
fective in slowing the flow of water and storing it quality degradation
for future use. These species are not arranged in
a random manner. Rather, they are organized in
The dominance of water-loving plant species
a natural structure consisting of three roughly
in the first zone serves as an indicator of riparian
parallel ecosystem bands, each consisting of spe-
health. These plants are critical for promoting
cies adapted to survive in the specific moisture
water recharge and increasing water table height
regime of that area and able to perform specific
(Martin and Chambers, 2001). It is not essential
ecological functions:
for native plant species to dominate in riparian
• The first band of vegetation, found at the edge
areas for these areas to provide environmental
of the water, consists of deep-rooted sedges
benefits. But water-loving plants that provide
and rushes.
functions similar to native species need to be
• The second band of vegetation, found in the present. However, water-tolerant exotic species
wet ground near the edge of the bank, con- — such as leafy spurge, purple loosestrife, or
sists of shrubs, trees, moisture loving grasses, salt cedar —grow very aggressively and over-
and water-tolerant broad-leaved plants (Huel, whelm species that are native to the area and
1998). more palatable to wildlife and livestock. In this
• The drier third band of vegetation, found way, exotic species decrease the ability of ripar-
where the riparian zone merges into the up- ian areas to maintain high water table levels, re-
lands, includes a mixture of riparian and tain streambank stability, provide forage to live-
upland plant species (Huel, 1998). stock, and support wildlife habitat (Huel, 1998).


The importance of water-loving plants in riparian areas

In the past, land management programs implemented in some arid areas recommended clearing
native, water-loving plants from riparian areas in order to reduce water-use competition and en-
courage the production of agronomic crops or forage grasses. However, the removal of these
plants eliminated many of the ecological benefits provided by riparian areas, including stream
stabilization, shading, and wildlife habitat (NRC, 2002). As a result, farmers and ranchers along
these unprotected streams lost land to streambank erosion and were faced with greater challenges
in reducing non-point source pollution.

Streambank stabilization. A diversity of plants work together to hold streambank soils in
place and protect them from erosion and undercutting by floodwaters, transported woody debris, or
ice jams. The deep, penetrating roots of sedges, rushes, grasses, and other herbaceous plants provide
structural support for streambanks, while the thicker, harder roots of woody plants protect streambanks
against bank scouring by floods and ice jams (Winward, 2000).

Photos by D. Redhege, Kerr Center
for Sustainable Agriculture

An eroded streambank that
recovered when it was protected
from grazing and allowed to
become stabilized by vegetation

When riparian areas restore themselves natu- The types of vegetation that naturally domi-
rally — following a fire, for instance —woody nate in riparian areas differ across locations.
species are often the first plants to become es- Grassy vegetation is more important for hold-
tablished. These woody plants stabilize stream ing together streambanks developed from sedi-
channels against the forces of erosion while nur- ments, while trees and shrubs dominate on the
turing the growth of water-loving grasses, sedges, steep, rocky banks of more rapidly moving and
rushes, and forbs (Elmore and Beschta, 2000). narrower headwater streams (Sovell et al., 2000).
The herbaceous plants then stabilize streambanks However, water-tolerant or water-loving plants
with their thick, deep roots, while their stems are more effective for holding streambanks in
trap sediments carried by runoff water and place than are plants more adapted to upland
stream-scouring floodwater. conditions, because they have deeper and stron-


Table 1. Vegetation Indicators for Riparian Areas
Healthy Riparian Areas Moderately Degraded Riparian Areas Degraded Riparian Areas

PAGE 8
Indicator
• effective water infiltration
Environmental • effective capture of sediments
Function of • vegetation provides some but not all • vegetation present ineffective in providing
• structural support of streambanks most environmental functions of riparian
environmental functions
Plants • reduces stream velocity during floods areas
• shade for reducing water loss and moderating
temperatures
• habitat for wildlife, birds, and aquatic species
• predominantly native, water-loving riparian • some non-native plant species and • only non-native species
Plant Species noxious weeds • noxious or invasive weeds present
vegetation • small number of plant species
Diversity • combination of sedges, rushes, grasses, • presence of some drought-tolerent
vegetation, similar to that in adjacent • trees and shrubs are absent
herbacous plants, shrubs and trees • presence of predominantly drought-tolerent
upland areas
vegetation, similar to that in adjacent upland
areas
Diversity of • both young and mature trees and shrubs are • few young trees and shrubs present • reduced plant establishment and survival
Plant Ages present • some dead or decadent plants present • all trees are old and in poor health

Plant Vigor and • healthy plant growth and reproduction • capability to produce seeds or tillers is • capability to produce seed or tillers is
• plant growth exceeds 80% of potential somewhat limited severely limited
Reproduction production • plant growth is 30-80% of potential • plant growth is poor, less than 30% of
production potential production
• diversity of plant species and plant ages • grazing has removed all of the palatable
Palatable • moderate decrease in percentage of vegetation
provides palatable vegetation throughout the palable plant species present
Vegetation growing season • palatable species of shrubs and trees are
• some browsing on palatable tree heavily browsed
• trees have an open or park-like appearance species
• willows and other palatable tree species
have a “mushroom-like” appearance
• full vegetation coverage throughout the year • sparse vegetation coverage, especially • bare soil over a large percentage of the soil
during the dry season surface
spring
Plant and Litter • litter layer present particularly during winter and • litter layer thinner than expected for • litter layer largely absent
Cover • provides woody debris that serves as shelter for location • limited amount of woody debris added to
fish and habitat for aquatic insects • reduced amount of woody debris added stream flow
to stream flow

Plant Litter • only small size litter is displaced • litter is concentrated around rocks, tree
• uniform distribution of litter trunks, and other obstructions
Movement and • plants remain standing following heavy rainfalls • scattered concentration of litter near
or snowmelts obstructions • plants are flattened by heavy flows of runoff
Plant Lodging • flattening of grasses in isolated areas water following rainstorms or snowmelts

Width of • riparian vegetation at least two channel widths • natural vegetation extends the width of • natural vegetation less than a third of width
Riparian Area on each side of stream half the channel on either side of stream of the channel on each side of stream
Sources: Belsky et al., 1999; Federal Interagency Stream Restoration Working Group, 2001; Hillard, C. and S. Reedyk. 2000; Naiman et al., 1992; Huel, 1998; Prichard, 1998; Renwick and Eden, 1999;

//PROTECTING RIPARIAN AREAS: FARMLAND MANAGEMENT STRATEGIES
Winward, 2000.

ger root systems. For example, Kentucky blue- channels (Platts, 1990, Ohmart, 1996). Water
grass (Poa pratensis) and redtop (Agrostis tables rise simultaneously in riparian areas as
stolonifera) provide good livestock forage, but streambanks build up, water absorption is in-
their root systems are not deep enough to stabi- creased, and water loss through evaporation de-
lize streambank sediments (Winward, 2000). creases. Under healthy riparian conditions, wa-
Thus, these plants often serve as indicators of ter tables rise until they reach the height of
disturbed or degraded riparian areas. Similarly, plants’ root zone on the former flood plains
trees that are not water tolerant do not develop (Elmore and Beschta, 2000). These riparian soils
as extensive root systems in riparian areas as do remain wet throughout most of the year.
water tolerant species. As a result, these trees Water recharge. The large water storage ca-
are unable to effectively stabilize streambanks pacity of riparian areas buffers the movement
and are likely to be undercut and fall into streams. of water from upland areas into streams. In-
stead of allowing water to flow directly into
streams following a rainstorm or snowmelt,
For guidelines on how to revegetate degraded healthy riparian areas hold and store water.
riparian areas, please see Appendix 2. Throughout the year, this water seeps slowly
into adjacent streams, providing water recharge
and moderating stream flow.
Table 1 provides a list of indicators that com-
Flood control. The ability of the porous, well-
pare vegetation characteristics in healthy ripar-
aggregated streambank soils to store vast quan-
ian areas to those in degraded areas.
tities of water also decreases the potential for
Water storage within streambanks . flooding. In addition, plants growing in ripar-
Healthy riparian areas that are well-vegetated ian areas control flooding by daily taking up and
have highly permeable soils and high stream transpiring thousands of gallons of water per
banks. They have a water table that extends acre (Elmore and Beschta, 2000). If water levels
underground and outward from the do reach flood stage, streambank vegetation sta-
streambanks and provides a large amount of bilizes streambanks and helps prevent streams
groundwater storage (Prichard, 1998). In con- from widening or changing course.
trast, degraded riparian areas have a low wa- Table 2 (next page) compares streambank and
ter table, sloping banks, and wide, shallow channel conditions in healthy and degraded ri-
streams, with limited storage capacity. parian areas.
A riparian area with a diversity of vegeta-
tion is able to trap 80 to 90% of the sediments
transported from fields (Naiman and Decamps, Water Decontamination
1997). The new sediments, along with lush plant
growth, facilitates both water infiltration into by Riparian Soils
riparian soils and increased water storage. As
vegetation grows, its stems and roots collect Riparian areas contain a combination of wet
more soil, while its leaves shade the soil and and dry soil zones that facilitate a variety of bio-
protect it against water loss through evapora- logical and chemical reactions. These reactions
tion. The seasonal death and decomposition of reduce the availability of some nutrients and de-
plants provides additional organic matter to the crease the toxicity of some contaminants
soil and further facilitates water infiltration and (Edwards, 2000). The presence of slowly decom-
storage. Organic matter holds water like a posing plant residues in these wet soils further
sponge and stimulates the growth of soil organ- facilitates water purification processes. Some
isms involved in the formation soil aggregates organic matter particles have a high ability to
and enhancing soil porosity. chemically capture and hold many potential con-
Streambank build-up. Sediment trapping by taminants, while others serve as sources of food
riparian vegetation increases the height of and energy for soil organisms involved in con-
streambanks, particularly along low-gradient taminant detoxification (Cohen, 1997).


Table 2. Soil Indicators for Riparian Areas
Indicator Healthy Riparian Areas Moderately Degraded Riparian Areas Degraded Riparian Areas

PAGE 10
• soil covered by growing plants and plant • soil organic matter content somewhat • low soil fertility and low concentration of
Organic matter residues throughout the year reduced organic matter
• organic matter has accumulated in the soil • some loss of topsoil • soil is bare in many areas
profile • moderate levels of soil biological activity • limited topsoil
• high soil biological activity • soil patches bare of vegetation • limited soil biological activity
• topsoils are deep • relatively high removal of residues from • limited return of plant residues to the soil
• soils are well aggregated soil system system
• moderate to poor soil aggregation • soils are sticky or grainy, not well aggregated

Diverse • peat builds up in riparian areas because area
• organic matter decomposes rapidly • moderate decomposition of organic is too wet or organic matter remains
microbial undecomposed because areas are too dry
• effective loss of nitrogen through denitrification matter
community • good soil aggregation by microbial slimes • ineffective denitrification
structure • poor soil aggregation

• soil is somewhat hard, especially during
Minimal • soil is soft, high organic matter content the dry season • soil is hard
compaction • good water infiltration • water infiltration is limited in some areas • little or no soil oggregation
• good soil aggregation • plants have difficulty getting water and • little or no water infitration
• healthy plant growth nutrients from the soil

• some loss of vegetation coverage • numerous areas bare of vegetation
Good • vegetation coverage over the soil surface • some runoff, erosion, or ponding of • loss of soil aggregation
infiltration • good soil aggregation water observed • soil is compacted
• relatively thick topsoil • soil compaction on surface or within • runoff and erosion observed even following
profile light to moderate storms

• good water infiltration • infiltration is somewhat restricted • infiltration is restricted
Limited runoff • deep topsoil with good water holding capacity • water holding capacity of soil is • high soil surface compaction
• high amount of organic matter in soil and good somewhat limited • limited water holding capacity of soil
soil aggregation • some soil compaction or relatively high
water table

Limited • complete vegetation cover over the soil surface • some small rills present • rills and gullies present
• no indication of soil movement • water becomes muddy only after heavy • soil is scoured where water flows over the
erosion surface
• stream is not muddied by runoff water rains
• soil build up behind rocks
• stream is muddied by runoff water

Sources: Belsky et al., 1999; Federal Interagency Stream Restoration Working Group, 2001; Naiman et al., 1992; Prichard, 1998; Renwick and Eden, 1999; Winward, 2000.


Detoxification of contaminants. Ripar-
ian soils have a high concentration of peat, a par-
The hyporheic zone. Healthy riparian soils
tially decomposed organic material formed un-
have a unique ecological zone composed of
der primarily anaerobic conditions. Under wet,
water-saturated oxygen-poor soils adjacent
anaerobic conditions organic materials decom-
to soils that are drier and oxygen-rich. Re-
pose more slowly than under aerobic conditions,
ferred to as the hyporheic zone, this transi-
since many more decomposing soil organisms
tion area between aerobic and anaerobic con-
require oxygen than thrive without it. Peat is a
ditions promotes biological transformations,
highly reactive material that has the ability to cap-
such as denitrification and pesticide detoxifi-
ture and hold many chemicals—nutrients, pesti-
cation, and chemical transformations that in-
cides, heavy metals, and other contaminants—
fluence the availability of phosphorus and iron
that flow off the uplands and into riparian areas
(Cohen, 1997).
(Cohen, 1997).
Other microorganisms found in the aerobic
Denitrification occurs when soil organisms and anaerobic areas of the riparian zone are able
that grow under aerobic conditions transform to degrade toxic contaminants such as pesti-
organic nitrogen into nitrate, followed by the cides. Habitat competition by other soil micro-
transformation of nitrate into atmospheric ni- organisms decreases populations of human and
trogen by bacteria that thrive under anaerobic animal pathogens, such as E. coli,
conditions. This process is important environ- cryptosporidium, or giardia, that may be trans-
mentally when the amount of nitrogen moving ported into streams from septic systems or ma-
across the watershed into riparian areas is nure piles (Stehman et al., 1996).
greater than the amount that can be used for Table 3 (next page) compares soil charac-
riparian plant growth. The overapplication of teristics in healthy riparian areas to those in de-
nitrogen-containing fertilizers and manure on graded areas.
agricultural and residential landscapes is the
primary source of nitrogen pollution of water- Riparian Areas and
ways. The amount of nitrogen entering streams
is reduced when riparian areas are able to cap- Habitat Preser vation
Preservation
ture and remove nitrogen from runoff water.
Riparian areas provide food and habitat for a
Natural riparian forests can denitrify and re-
diversity of soil, aquatic, and terrestrial organ-
lease 25 to 35 pounds of nitrogen per acre per
isms. A multistoried plant canopy of annual
year (Cole, 1981).
and perennial grasses and forbs, as well as juve-
Phosphorus availability . Overapplication nile and mature shrubs and trees, provides a
of fertilizer and manure can also overload the varied aboveground habitat for birds and wild-
soil with phosphorus. Iron, aluminum, and life and a belowground habitat for burrowing
calcium in the soil can bind excess phosphorus. animals and soil organisms. Exposed roots and
In flooded soils, iron binds less phosphorus than irregular streambanks provide breeding areas
it does in drier, aerobic soils. This decreased for many aquatic species, as well as habitat for
binding ability increases the availability of phos- algae and macroinvertebrates that are used as
phorus both for plant uptake and for movement food by fish and other aquatic life. In addition,
into surface water (Green and Kaufman, 1989). overhanging branches of riparian trees and
Since riparian areas have a limited ability to hold sloughed off residues of riparian plants provide
excess phosphorus, they are relatively ineffec- aquatic life with shade and habitat.
tive in protecting streams against poor phospho- Aquatic habitat . Healthy riparian areas
rus management practices on upland areas. protect fish habitat by minimizing the movement
Thus, good upland management is necessary to of eroded sediments into streams. Heavy silt
protect against phosphorus pollution. loads disrupt reproductive behavior and destroy
feeding and spawing areas for many aquatic
For additional information on the ability of ri- species (Thompson, 1984). For example, trout
parian areas to control phosphorus move- require gravel for reproduction and egg laying,
ment into streams, please see Appendix 3. while various gamefish need relatively clear


Table 3. Streambank and Channel Indicators

PAGE 12
• some streambank erosion • streambanks are high
Streambank • banks are at elevation of active flood plain • some deep rooted riparian plants • bends eroded by flowing water
Stability • little or no streambank erosion replaced by more shallow rooted or • plant roots either not present or uable to hold
• many strong, fine roots hold streambank in woody plant species banks against scouring
place • trees are falling into stream

Stream • channel is relatively narrow • channel is wider than under natural • channel is shallow and wide
• banks are relatively straight with deep undercut conditions • banks are laid back
Channel Shape
that provides shade for aquatic species • banks are broken down in isolated areas • banks are trampled where livestock enter the
• stream has pools and meanders • some loss of pools and meanders water to drink or cross the stream
• loss of pools and meanders

• relatively frequent occurrence of riffles • occassional riffles • water is generally flat
• distance between riffles is no more than 7 • bottom contours provide some aquatic • if riffles are present, they are shallow and
times the measurement of the width of the habitat provide poor aquatic habitat
Frequency of stream • distance between riffles is no more than • distance between riffles is greater than 20
Riffles 20 times the measurement of the width times the measurement of the width of the
of the stream stream

• water table remains high and stable throughout • water table is not at bankful level • water table is low or varies greatly throughout
the year • soil surface may dry out during the dry the year
Riparian Water • water loving vegetation predominates season • drought tolerant or upland vegetation has
Table • riparian area provides an interface between wet • some drought tolerent upland plants replaced riparian vegetation
and dry environments present in the riparian zone • water table is too low to facilitate chemical
and biological interactions between wet and
dry conditions

• stream has not been subject to channelization, • some channelization present, usually in • extensive channelization, especially in urban
stream alteration, or dredging areas of bridges or in urban areas areas
Channel
• evidence of dredging or channelization • banks shored with gabion or cement
Alternation having occurred over 20 years ago • instream habitat greatly altered or removed
• drainage outlets from agricultural lands entirely

Sources: Belsky et al., 1999; Federal Interagency Stream Restoration Working Group, 2001; Huel, 1998; Naiman et al., 1992; Prichard, 1998; Renwick and Eden, 1999; Winward, 2000.


water to see prey and detect visual clues used in for food outside of these areas. Other bird spe-
their social and reproductive behavior (Cohen, cies prefer nesting in riparian areas even if they
1997). can nest elsewhere. However, degradation of
The ability of riparian areas to stabilize riparian areas reduces populations of these spe-
stream flow levels throughout the year is also cies (Bureau of Land Management and Partners
critical to the survival of many fish and other in Flight, 2000).
aquatic species. Fish need enough water in
streams to navigate and find food. If a stream Appendix 4 provides guidelines for adequate
becomes polluted, decreasing water levels may buffer widths to meet various environmental
concentrate pollutants to levels that are too toxic objectives.
for fish. High water levels caused by stream
flashing can rapidly increase water tempera-
tures, which can be fatal to some fish and other Riparian vegetation growth, soil fertility and
aquatic organisms. Stable water levels provide porosity, water quality, and stream flow condi-
the moderate water temperatures required for tions all affect the ability of fish and wildlife to
the growth of fish and the aquatic organisms thrive in streams and their associated riparian
that they use for food (Wenger, 1999; Cohen, areas. Table 4 compares habitat conditions pro-
1997). vided by healthy riparian areas to those of de-
Large woody debris that falls into streams graded areas.
traps sediments and creates pools that provide
protected, shaded habitats for aquatic species L and Management
(Stuart et al., 1994). For trout, vegetation cover
provides food and places to hide from preda- Protect
Practices to Protect
tors (Burgess, 1985). For many aquatic organ-
isms, leaves, twigs, and insects falling from over-
hanging trees are an important food source
Riparian Areas
(Hillard and Reedyk, 2000). In naturally forested Key components of riparian protection are
areas, retaining at least 50% of the tree canopy is maintaining good soil and water conservation
critical for providing moderated temperatures re- practices across the landscape and preserving,
quired for good fish habitat (Whitaker-Hoagland, as much as possible, the integrity of the three
1998). natural riparian zones. Specific land manage-
ment practices that protect riparian areas in-
errestrial
Ter restrial wildlife habitat. Riparian ar- clude:
eas are the main source of moisture for plants
and wildlife within watersheds, especially in • Maintaining a vegetative cover over the soil
arid regions or during the dry season in more throughout the year
temperate climates. Riparian areas with a high • Minimizing animal trampling or vehicle traf-
density and diversity of foliage, both vertically fic on wet soils
and horizontally, can provide habitat and food • Avoiding overuse of fertilizers or manure
for a diversity of birds and other terrestrial wild- that may be transported into riparian areas
life, including many endangered and threatened
species (NRCS/RCA, • Avoiding applying or dis-
1996). Many animals posing of toxic chemicals on
also use these moist ar- soils
eas as travel corridors be- • Protecting against loss of
tween feeding areas plant diversity and vitality in
(Henry et al., 1999). riparian areas
Many bird species
• Protecting against the es-
depend on riparian areas
tablishment of exotic or non
for food, shelter, and
water-loving species in riparian
nesting sites. Some bird
species require riparian areas
areas for nesting, al- Photo by USDA NRCS • Avoiding practices that ar-
though they may forage tificially alter stream flow


Table 4. Indicators of Aquatic and Riparian Wildlife

PAGE 14
• adequate water supply and quantity throughout
• streams dry up during the dry season
Water quality the year
• water tables fluctuate throughout the • presence of mancroinvertebrate indicators of
and quantity • presence of macroinvertebrate indicators of
year poor water quality
good water quality such as caddis flies and
• some contaminants present in the • water contains toxic levels of sediments,
mayflies
water pesticides, heavy metals, or nutrients
• water contains few contaminant such as
• excessive aquatic weed growth in streams
pesticides, heavy metals, or excess nutrients
• stream temperatures are high
• some reduction in streamside vegetation • lack of streamside vegetation
Water • streamside vegetation cools streams
• decrease in the availability of aquatic • low dissoloved oxygen levels
Temperature • undercut streambanks provide shade
species used for food • cool water aquatic species replaced by warm
• presence of aquatic species used for fish food
water species
• lack of aquatic species to provide food for fish

• loss of stream pools
Stream Pools • numerous both deep and shallow stream pools
• decrease in stream pools • low amounts of woody debris due to loss of
• woody debris present to form pools
• woody vegetation replaced by trees
• complex channel structures
herbaceous vegetation • channel straightening or modification to
simplify channel structure

Sediment • low amount of sediments in streams
• stream muddy looking because of sediment
Load • water is clear or tea colored
• sediment levels in streams increasing load
• floating algal mats or scum may be present

• natural concentrations of nutrients and • nutrient and pathogen levels somewhat • high concentrations of nutriets and pathogens
Nutrient and pathogens from wildlife in area
Pathogen elevated in water
• little or no evidence of livestock access to • manure present but not concentrated • extensive amounts of manure on banks and in
Concentration streams on or near streambanks streams

• native plant communities are dominant • some non-native species are present • non-native species are dominant vegetation
vegetation • land is used for grazing or other • land is grazed or mowed while waterfowl are
• land use delayed until chicks have left the nest agricultural uses each year nesting
Waterfowl • land is rested for several years to allow for
Habitat • land is insufficiently rested to provide • vegetation regrowth does not provide sufficient
homing, larger clutches, and earlier nesting vegetation cover for nesting cover for nesting
• sufficient blocks of land are protected to provide
corridors of movement and foraging

continued on page 15


Table 4. Indicators of Aquatic and Riparian Wildlife (cont’d.)

• fish cover provided by woody debris,
overhanging vegetation, bank cobbles, pools, • decrease in the types of fish cover • little or no fish cover provided
riffles, and undercut banks available • water contaminated by sediments and
Fish Habitat • water temperatures moderated by vegetation • some soil loss and pollution pollution
cover • water levels are unstable • streams are ephemeral
• minimal soil loss and pollution
• good supply of aquatic insect species for fish
to eat

Insect and • habitat provided by woody fine debris, • decrease in the amount of habitat sites • few or no habitat sites present
Invertebrate submerged logs, leaf packs, undercut banks available
Habitat and cobbles

Mammal • trails, tracks, feeding areas, and resting areas
Diversity are present

Macro- • predominately pollution intolerent species such • predominantly moderately tolerent • if macroinvertebrates are present,
invertebrate as caddisflies, mayflies, stoneflies and riffle species such as damsel flies, predominantly pollution tolerant species such
Diversity beetles dragonflies, aquatic sowbugs, blackfish as midges, craneflies, horseflies, leeches,
and crayfish aquatic earthworms, and tubificid worms

• presence of bird nests • decreasing presence of obligate bird
• species that are obligate dependent on riparian species • lack of bird nest
Bird Diversity areas are present, for example Common • presence of riparian dependent bird • if birds are present, species are similar to
Yellowthrout, Song Sparrow, and Willow species such as goldfinch, bank upland areas
Flycatcher swallow, grosbeak, or red-headed
woodpecker

• predominance of native species • native species are not present
Fish Diversity • pollution intolerent species, such as trout, • pollution tolerent species such as carp

small mouth bass and sunfish are present predominate

Sources: Belsky et al., 1999; Bureau of Land Management and Partners in Flight, 2000; Federal Interagency Stream Restoration Working Group, 2001; Huel, 1998; Mosley et al., 1998; Prichard, 1998;
Sovell et al., 2000; Winward, 2000.

PAGE 15

Watershed
Community Watershed water pollution and riparian degradation. Mean-
while, those involved in implementing good wa-
tershed and riparian management practices of-
Collaboration to Protect
Protect ten go unnoticed and under-compensated.
Why is this so? Most watershed and riparian
Riparian Areas degradation is non-point source pollution, which
by definition means that it is difficult to identify
specific land use practices responsible for this
Watershed councils lay the cultural founda- pollution. Secondly, good upland and riparian
tions for a lasting way of life. They establish grazing management practices in one part of the
the tradition of responsible speech, of civil watershed cannot, in most cases, compensate for
democracy, and of making decisions based poor land management practices in other parts
on factual information and well-articulated val- of the watershed. Thirdly, and possibly most
ues. They embody the long-term perspec- importantly, land users who implement soil and
tive of sustainability, seeking not quick fixes water conservation practices often are asked to
but deeper understanding and new alterna- bear the costs of implementing changes while
tives. obtaining few of the benefits. This disparity be-
tween those who pay and those who benefit of-
Alan T. During (quoted in Wood et al.,1997) ten discourages farmers and other landowners
from implementing soil conservation and ripar-
Farmers, ranchers, and conservationists of- ian management practices.
ten become embroiled in debates over the use of
riparian areas. If you are a farmer or rancher,
you may be concerned about the loss of access For more information on the economic costs
to grazing land and watering areas as well as and benefits of riparian buffer protection,
costs associated with management practices, please see Appendix 5.
such as the installation and maintenance of
fences. If you are a conservationist or environ- The Bureau of Land Management, the U.S.
mentalist, you may be concerned about the loss Forest Service, and the Natural Resources Con-
of habitat for birds, wildlife, and aquatic spe- servation Service understand that programs de-
cies that depend on this diverse and fragile eco- signed to promote soil and water conservation
system. If you are a downstream water user, practices are often contentious. In their joint
you are no doubt concerned about the contami- letter announcing the initiation of a program to
nation of drinking and recreational waters with help restore riparian areas (PLF, 2002), the agen-
nutrients, pathogens, and pesticides. cies state that riparian restoration:
Pinpointing sources and causes of riparian
degradation and the associated degradation of will not happen by regulation, changes in the
water quality is very contentious. Farmers and law, more money, or any of the normal
ranchers often assert that livestock grazing in bureaucratic approaches. It will only occur
riparian areas cause less damage than construc- through the integration of ecological, eco-
tion activities, septic tanks, and industrial dis- nomic, and social factors and participation of
charges. Conservationists often counter this as- affected interests.
sertion by contending that agriculture is the pri- For watershed and riparian management
mary source of nonpoint pollution in many ar- programs to be effective, they should include
eas, and they maintain that excluding agricul- the following elements (Wood et al., 1997):
tural practices from riparian areas is the best • Active involvement by community members
method for protecting wildlife habitat and wa- from across the watershed who represent a
ter quality.
broad array of perspectives and problems
To work together in restoring riparian ar-
eas, community members need to understand • Collaborative identification of program ob-
that riparian areas are only protected if all land jectives, such as protecting high value re-
users across the watershed work together. Get- sources and solving problems that most
ting this cooperation is often difficult since wa- threaten the sustainability of the watershed
tershed users can easily blame others for causing • Education and outreach


• Community access to and sharing of factual on a set of sustainable land management objec-
information on watershed economic, envi- tives.
ronmental, and social conditions
• Willingness to discuss and address critical but
often contentious resource issues such as
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There is much scientific literature to docu- effectiveness of revegetation. In: B.A.
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and protected riparian habitats. As all commu- riparian community of a small mountain
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