|
Best
Management
Practices
FOREWORD
Best Management Practices
(BMPs) are effective, practical, structural or nonstructural
methods which prevent or reduce the movement of sediment,
nutrients, pesticides and other pollutants from the land to
surface or ground water, or which otherwise protect water
quality from potential adverse effects of silvicultural
activities. These practices are developed to achieve a
balance between water quality protection and the production
of wood crops within natural and economic limitations.
A thorough understanding of BMPs and the flexibility in
their application are of vital importance in selecting BMPS
which offer site specific control of potential nonpoint
source pollution. With each situation encountered at various
sites, there may be more than one correct BMP for reducing
or controlling potential nonpoint source pollution. Care
must also be taken to select BMPs that are practical and
economical while maintaining both water quality and the
productivity of forest land.
The Federal Water Pollution Control Act Amendments of 1972,
Public Law 92-500 (and as amended by Sec. 319, 1986),
require the management of nonpoint sources of water
pollution from sources including forest-related activities.
BMPs have been developed to guide forest landowners, other
land managers and timber harvesters toward voluntary
compliance with this act. Maintenance of water quality to
provide "fishable" and "swimmable" waters is central to this
law's objectives. The Environmental Protection Agency (EPA)
recognizes the use of BMPs as an acceptable method of
reducing nonpoint source pollution.
Nonpoint source is diffuse pollution that comes from almost
everywhere; it even occurs naturally to a certain extent.
The amount of pollutants from any particular spot is small
and insignificant, but when combined from over the
landscape, can create water quality problems.
Although it is unrealistic to expect that all
nonpoint source pollution can be eliminated, BMPs can be
used to minimize the impact of forestry practices on water
quality. These practices must be reasonable, achievable and
cost effective. The adoption and use of BMPs will
provide the mechanism for attaining the following water
quality goals:
- to maintain the integrity
of stream courses;
- to reduce the volume of
surface runoff originating from an area of forest
management disturbance and running directly into surface
water;
- to minimize the movement
of pollutants i.e. pesticides, nutrients, petroleum
products, etc. and sediment to surface and ground
water;
- to stabilize exposed
mineral soil areas through natural or artificial
revegetation means.
The intent of this
guide is to promote better stewardship of the forest
resources. This guide delineates environmentally responsible
land management methods which, when applied properly,
minimizes adverse impacts on the forest ecosystem and
maximizes landowner objectives. Unusual situations may arise
or pollution control measures other than those recommended
here may be found. In these cases, common sense is most
often the best guide.
Information presented
in this guide is not to be used as the basis for setting
water quality standards or as the basis of required use of
watershed protection practices. Compliance with any
watershed protection practices would be on a voluntary basis
backed up with a public water quality education and
awareness program. Changing of water quality standards or
the required use of protection practices should not be
attempted without careful study of the beneficial effects
gained from modifying existing silvicultural practices now
in use.
INTRODUCTION
The Division of Forestry and Wildlife (DOFAW) is
mandated by HRS, Chapter 183 to "...devise ways and means of
protecting, extending, increasing, and utilizing the forests
and forest reserves, more particularly for protecting and
developing the springs, streams, and sources of water supply
to increase and make that water supply available for
use..."
The number one resource that is generated by the forest is
water. Since the establishment of the Department of
Agriculture and Forestry in 1900, the concern for the
protection of forest lands for the purpose of water has been
a high priority. Fencing to keep out wild cattle and other
feral animals and reforestation efforts to re-establish
watersheds have been the key to the continuance of the
production of high quality water.
In 1961, Hawaii created, by law, the nation's first
statewide zoning districts, and today approximately 95% of
the Hawaii's four million acres are zoned for agricultural
or conservation uses. The Conservation district, which is
under the jurisdiction of the Department of Land and Natural
Resources (DLNR), encompasses almost one-half of the State,
of which one million acres is state-owned. The majority of
Conservation lands are covered by forests, but also contain
grasslands, coastlines, cliffs, offshore islets, and
wetlands. Vegetative communities include lowland and montane
rainforests and unique examples of tropical biodiversity,
much of it endangered.
The Division of Forestry and Wildlife recognizes the need
for responsible stewardship of the natural resources, which
include soil and water. The success of BMPs to
protect water quality within Hawaii depends on mutual
cooperation and trust among landowners, industry,
environmentalists, wood producers, regulatory agencies,
governmental officials, and the general public.
All have an interest in good land management as it relates
to water quality.
THE FOREST/WATER RELATIONSHIP
The forest and water resources are mutually dependent upon
one another. Forests depend on water, namely rain, surface
water, and groundwater for their growth and reproduction.
Major long-term changes in the water supply can cause
permanent changes in the content, quality and vitality of
forest lands.
On the other hand, surface and groundwater quantity and
quality are largely influenced by the surface on which rain
falls and through which it percolates. The tremendous
filtering capacity of forest lands provide effective and
high quality groundwater recharge.
Hawaii's streams and aquifers all benefit from the presence
of forests. In addition to these water quality benefits,
forests provide needed wood and fiber products, wildlife
habitat, aquatic resources and habitat, recreation values
and aesthetic benefits. It is in managing forests for these
benefits that damage to the water resource can result.
Following is a brief discussion of the most commonly used
forest management practices and the impacts they can have on
the quality of the water resource.
Timber
Harvesting
The removal of trees from a site has little impact on water
quality, as long as the trees do not provide vital shade to
streams and as long as the slope of the land is not
excessive. The natural warmth of many streams can be
exaggerated by removing shading vegetation from their banks.
Increased water temperature promotes lower dissolved oxygen
levels, placing stress on fish and other aquatic
organisms.
Removing timber per se does not directly cause significant
water quality changes, since ground cover is not excessively
disturbed during proper logging operations. On steep slopes,
however, careless timber removal can increase the likelihood
of runoff and soil loss. This may lead to water quality
degradation as well as a loss of site productivity. Steep
areas should therefore be logged carefully using proper
harvesting techniques for the sake of both water quality
protection and site protection.
Road
Construction and Drainage Techniques
All facets and phases of a sound forest management program
rely heavily on accessibility to the forest. Consequently,
temporary and permanent access roads are necessary
components of all management programs. They are also one of
the most costly investments made in a forests.
Temporary access roads are constructed to facilitate
harvesting operations, site preparation and planting and
often abandoned after the new stand is established. When
abandoned, these temporary roads are normally allowed to
revegetate naturally or are planted with trees.
Pollutants
from Silvicultural Activities
The major types of water pollutants that can be generated
from forest management disturbances to the forest ecosystem
include sediment, nutrients, pesticides, and debris.
1) Sediment
Sediment is the most common pollutant resulting from
silvicultural activities. Sediment principally results from
erosion of soil, but may also include organic matter.
Excessive sediment upsets balanced ecology within streams by
smothering bottom dwelling organisms in the water,
interfering with photosynthesis by reducing light
penetration, serving as carriers of nutrients and
pesticides, inhibiting fish reproduction and altering stream
flow.
2) Nutrients
Nutrients, primarily phosphorous and nitrogen fertilizers,
are sometimes applied to the forest to stimulate tree
growth. Soluble nutrients may reach surface or ground water
through runoff, seepage, and percolation. Insoluble forms
may be absorbed on soil particles and reach water by direct
wash-off of debris and recently applied fertilizer.
Excessive nutrients lead to an imbalance in natural life
cycles of water bodies.
3) Pesticides
Pesticides, if applied during silvicultural activities, may
be soluble or insoluble. Pesticides in surface or ground
water may result in toxicity problems, affecting water
quality and food sources for aquatic life.
4) Debris
Tree limbs, tree tops, and other waste materials are the
principal organic pollutants from silviculture. They reach
streams through direct pushing or felling into water
drainages, and washout during storms. Organic materials may
place an oxygen demand on the receiving water body during
the decomposition process. In addition, associated problems
may include odor, color, taste and nutrients. Inorganic
material such as oil cans and pop bottles are also
considered nonpoint source debris.
1.0
Forest Roads
Standards and
Use
Forest roads are managed to provide adequate access to lands
for timber management, fire suppression, wildlife habitat
improvement and a variety of dispersed and developed
recreational activities. Generally, these are low volume
roads that must carry heavy loads for short periods of time.
The potential for adverse impacts from forest roads exists
in areas where steep slopes, erodible soils, or where forest
roads are located near water. Forest roads cause
more erosion than any other forestry activity. Most
of this erosion can be prevented by locating, constructing,
and maintaining roads to minimize soil movement and
pollution of streams. The need for higher standard roads can
be alleviated through better road-use management. Design
roads to the minimum standard necessary to accommodate
anticipated use and equipment.
Planning, Design, and
Location
A well planned access system is a sound method of reducing
erosion and sedimentation in areas requiring frequent or
temporary access. Proper location and construction of roads
will provide for safety, longer operating periods, lower
maintenance and operating costs, and minimal impacts to
water quality. The value of the resource served and site
characteristics will influence the choice of road
construction standards and maintenance activities. The
following practices are recommended:
- Use a design to minimize
damage to soil and water quality.
- Roads should be designed
no wider than necessary to accommodate the immediate
anticipated use.
- Design cut and fill slopes
to minimize mass soil movement.
- Provide culverts, dips,
water bars, and cross drainages to minimize road bed
erosion.
- Design bridge and culvert
installations using stream flow data, with a margin of
safety proportional to the importance of the road and the
protected resources.
- Provide drainage where
surface and groundwater cause slope instability.
- Avoid diverting water from
natural drainage ways. Dips, water bars, and cross
drainage culverts should be placed above stream crossings
so that water can be filtered through vegetative buffers
before entering streams.
- Locate roads to fit the
topography and minimize alterations to the natural
features.
- Avoid marshes and
wetlands.
- Minimize the number of
stream crossings.
- Cross streams at right
angles to the stream channel.
- A road may not be located
in a Streamside Management Zone (SMZ) except where access
is needed to a water crossing, or where there is no
feasible alternative. A road in any SMZ must be designed
and located to minimize adverse effects on fish habitat
and water quality.
Construction
Once the road's location and design is staked out, road
construction begins. Timber is out, logs and vegetation are
removed and piled along the lower side of the
right-of-way.
Most forest roads are built by excavating a road surface.
Road design and layout on-the-ground show machine operators
the proper cut slopes and indicate cut slope steepness. The
bulldozer starts at the top of the cut slope, excavating and
sidecasting material until the desired road grade and width
is obtained. Material from cuts is often pushed in front of
the blade to areas where fill is needed. Road fill is used
to cover culverts and build up flat areas. Since fill must
support traffic, it needs to be spread and compacted in
layers to develop strength. The following practices are
recommended:
- Construct roads when
moisture and soil conditions are not likely to result in
excessive erosion or soil movement.
- The boundaries of all SMZs
shall be defined on the ground prior to the beginning of
any earth-moving activity.
- Construct a road
sufficient to carry the anticipated traffic load with
reasonable safety and with minimum environmental
impact.
- When using existing roads,
reconstruct only to the extent necessary to provide
adequate drainage and safety.
- Avoid construction during
wet periods, when possible, to minimize unnecessary soil
disturbance and compaction.
- Road grades should be kept
at less than 10%, except where terrain requires short,
steep grades.
- Minimize the number of
stream crossings. Stream crossing construction should
minimize disturbance of the area in which the crossing is
being constructed.
- As slope increases,
additional diversion ditches should be constructed to
reduce the damages caused by soil erosion; ditches,
adequate culverts, cross drains, etc., should be
installed concurrent with construction.
- To control erosion, cut
and fill slopes should conform to a design appropriate
for the particular soil type and topography.
- Stumps, logs, and slash
should be disposed of outside of the road prism; in no
cases should they be covered with fill material and
incorporated into road beds.
- Stabilize the side banks
of a road during construction to aid in the control of
erosion and road deterioration; this may require mesh or
other stabilizing material in addition to planting and/or
seeding and other structural measures.
- Water bars should be
located to take advantage of existing wing ditches and
cross drainage. Water bars should be constructed at an
angle of 30 to 45 degrees to the road. Water bars should
be periodically inspected and damage or breeches should
be promptly corrected. Install water bars at recommended
intervals to provide the drainage. Water bar spacing
recommendations are as follows:
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Grade of
Road
|
Distance
Between Water Bars
|
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2%
|
250
ft.
|
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5%
|
135
ft.
|
|
10%
|
80
ft.
|
|
15%
|
60
ft.
|
|
20%
|
45
ft.
|
|
25%
|
40
ft.
|
|
30%
|
35
ft.
|
|
40%
|
30
ft.
|
Water bars may need to be
spaced closer together depending on soil type and
rainfall.
- Bridges and overflow
culverts should be constructed to minimize changes in
natural stream beds during high water.
- Culverts on perennial
streams should be installed low enough to allow passage
of aquatic life during low water.
Maintenance
Maintenance of active and inactive roads shall be sufficient
to maintain a stable surface, keep the drainage system
operating, and protect the quality of streams. The following
are recommended:
- Maintenance should include
cleaning dips and crossdrains, repairing ditches, marking
culverts inlets to aid in location, and clearing debris
from culverts.
- Keep culverts, flumes, and
ditches functional before and during the rainy season to
diminish danger of clogging and the possibility of
washouts. This can be done by clearing away any sediment
or vegetation that could cause a problem. Provide for
practical and scheduled preventative maintenance programs
for high risk sites that will address the problems
associated with high intensity rainfall events.
- Conduct road surface
maintenance as necessary to minimize erosion of the
surface and subgrade.
- During operations, keep
the road surface crowned or outsloped, and keep the
downhill side of the road free from berms except those
intentionally constructed for protection of fill.
- Avoid using roads during
wet periods if such use would likely damage the road
drainage features.
- Water bars should be
inspected after major rain storms and damage or breeches
should be promptly corrected.
Harvesting - Temporary Access
Roads and Landings
- The location of temporary
access roads (logging roads) should be planned before
operations begin.
- Road construction should
be kept to a minimum.
- Landings should be located
to minimize the adverse impact of skidding on the natural
drainage pattern.
- Logging roads and landings
should be located on firm ground.
- Landings should be kept as
small an area as possible.
- When operations are
completed, provisions should be made to divert water
run-off from the landings and roads.
2.0
Pre-Harvest Planning
Pre-harvest planning is the collection of information about
the area to be harvested and the synthesis of that
information into an effective environmental plan. This plan
will consider the silvicultural prescription for the species
and site, the best estimate of the time and method of
harvest and any post-harvest site preparation and
reforestation activities.
At this stage, it is assumed that all federal, state, and
local government regulations regarding harvesting have been
met.
An effective pre-harvest plan will take into consideration
all aspects of the timber harvest which may lead to water
quality degradation and plan for the implementation of BMPs
which will minimize or avoid the adverse effects of the
operation. The objective of pre-harvest planning from the
perspective of non-point source pollution is to determine
which BMPs are necessary to protect water quality and how
those BMPs will be implemented. The following is
recommended:
(1) A pre-harvest plan should
include the following information:
A. Physical and administrative description
- Property boundaries &
administrative boundaries (zoning, etc.)
- Topography
- Location of streams and
drainages
- Location of SMZs and
buffer strips
- Forest types
- Soil types
- Areas of ecological and/or
archaeological concerns
B. Management
Activities
- Design and construction
techniques for all new roads, skid trails, and landings
or modification of existing roads, skid trails and
landings.
- Felling and bucking
techniques
- Yarding systems and
layout
- Planned stream
crossings
- Disposal of waste
materials (machine lubricants)
- Post-harvest site
preparation
- Reforestation
activities
(2) The use of topographic
maps, road maps, aerial photos, forest type maps, and soil
surveys in combination with field reconnaissance is
essential to determine site conditions and plan
operations.
(3) Field reconnaissance with a trained forester or one who
is knowledgeable about the specific area is highly
recommended.
(4) Preliminary planning should consider the maintenance of
existing drainage patterns and the location of
environmentally sensitive areas such as streams, wet areas,
and high erosion hazard areas.
(5) The design of roads, skid trails, and landings shall be
integrated to minimize their impact.
(6) The grade of logging roads and skid trails should be
less than 10% when possible, with 3-5% being the norm. Long,
straight, unbroken grades are to be avoided. Adequate
surface drainage shall be provided.
(7) Time the harvesting activity for the season or moisture
conditions when the least impact occurs.
(8) A final pre-harvest site review shall be conducted by
management so that road alignments and other considerations
can be visually checked prior to road construction. The
reconnaissance plan shall be modified as necessary to make
desirable adjustments based on the final site review.
2.1
Timber Harvesting
Standards and use
Timber harvesting is an integral part of most forest
management programs. Harvesting operations cause a temporary
disturbance in the forest as well as diminish water quality.
However, it can be conducted in a manner where the impact to
water quality is minimized and the re-establishment of
vegetative cover is realized. Guidelines to help reduce the
potential for nonpoint source pollution from harvesting
trees are as follows:
Felling and
Bucking
- Careful felling can
minimize the impact of subsequent phases of the logging
operation.
- Trees should not be felled
into streams, except where no safe alternative exists. In
the latter case, such trees should be removed
promptly.
Skidding
- Skidding should be done so
as to avoid disrupting natural drainage and to prevent
excessive soil displacement
- Stream channels or road
ditches should not be used as skid trails.
- Skid trails on steep
slopes should have occasional water bars.
- Servicing of equipment
involving fuel, lubricants, or coolants should be
performed in places where these materials cannot enter
streams. Spent oil should be collected for proper
disposal, never poured on the ground.
- Upon completion of
logging, erosion-prone areas should be mulched or
seeded.
Mechanical
Site Preparation
- Avoid excessive soil
compaction.
- Minimize erosion and the
movement of sediment into waters.
- Prevent accumulation of
debris in ponds, streams, or rivers.
- Windrows, disking,
bedding, and planting with "furrow" type mechanical
planters should follow contours.
- Avoid complete disking of
steep slopes with extremely erodible soil.
- Plant trees on
contour.
Disposal
of Debris and Litter
- Logging debris in streams
should be removed immediately.
- Debris from landings
should not be pushed into drains, streams or Streamside
Management Zones (SMZs)
- All trash associated with
the logging operation should be promptly removed (not
buried) and hauled to a legal disposal site.
3.0
Silvicultural Chemical
Management
Description
and Purpose
Pesticides are used on forest lands to facilitate meeting
forest management objectives. The purpose of a pesticide
application is to rid an area of undesirable vegetation or
control insects or diseases to promote the establishment,
survival, growth or maintenance of a desired species or
condition.
Planning
Considerations
Planning is an essential first step in reducing pest
problems. A plan is needed by which the application of
pesticides is utilized in an efficient manner that produces
no adverse impacts on the environment. The maintenance of
water quality is an important consideration in all aspects
of pesticide operation planning.
Pesticide
Selection
When the decision is made to use pesticides, choose products
suitable for use on the target species and registered for
the intended uses. Use only pesticides registered by the
Environmental Protection Agency. Prior to using any
pesticide, carefully read and follow all label
directions.
When selecting pesticide options, more than effectiveness
and cost should be evaluated. Consideration should be given
to site factors, application conditions and techniques and
products that can influence impacts to water quality.
Three main characteristics can greatly affect a pesticide
potential to contaminate surface or ground water. They are
solubility, absorption and breakdown rate.
1) Solubility
Solubility is the ability of a pesticide to dissolve in
water. The greater the solubility, the greater the chance
that the chemical will leach to ground water.
2) Absorption
Absorption is the inherent ability of a pesticide to bind
with soil. Some pesticides stick very tightly to soil while
others are easily dislodged. A greater absorption means a
pesticide will remain longer in the soil and thus be less
likely to leach down into the ground water before it has
degraded. Absorption increases as soil organic matter
increases.
3) Breakdown Rate
Breakdown rate or half-life is the time a pesticide takes to
degrade or breakdown into other chemical forms. Pesticides
that do not break down quickly can be hazardous if they move
to ground water or surface water.
In a given situation, pesticides with the highest water
solubilities, greatest persistence, lowest affinities for
absorption to organic matter and other soil components, and
highest application rates have the greatest potential for
movement in surface water or to ground water. An alternative
means of minimizing the potential movement of a pesticide is
to select a non-broadcast application technique for the same
pesticide that reduces the amount of the chemical applied
directly to the soil.
Procedures for Chemical
Use
Proper pesticide management practices make efficient use of
chemical while preventing contamination of surface water or
ground water. Residues of pesticides used in forestry can
affect water quality at several phases of the chemical use
cycle. These phases are:
- transportation
- storage
- mixing and
loading
- application
- cleanup
- disposal To minimize
potential impacts on water quality, use of the following
practices is encouraged.
A)
Transportation
- Inspect all containers
prior to loading and ensure all caps, plugs and bungs are
tightened
- Handle containers
carefully when loading them onto vehicles
- Secure containers properly
to prevent shifting during transport
- Check containers
periodically enroute
- Limit access to containers
during transport to prevent tampering
- Educate and inform the
driver of the proper transportation
precautions
- Never transport pesticides
unless arrangements have been made to receive and store
them properly
B)
Storage
- Chemicals should be
managed and stored in accordance with all applicable
federal, state, or local regulations. These would
include:
- The EPA container
registration label, as printed on the label
- Label instruction for use
as provided by the manufacturer
- Requirements or the use,
application, and registration of pesticides
- Requirements relating to
the licensing of applicators
- All containers should be
labeled in accordance with applicable federal, state and
local regulations.
- Store pesticides in their
original containers with labels intact.
- Do not store pesticides
for extended periods in buildings that can not contain a
complete spill from the largest container being
stored.
- Check containers prior to
storage and periodically during storage to ensure that
they are properly sealed.
- Locate pesticide storage
facilities at sites that minimize the possibility of
impacts of water quality in case accidents or fires
occur.
- Use storage buildings that
have floors constructed of concrete or other impermeable
materials so that spills are easy to clean up.
- Ensure that storage
facilities can be secured under lock and key.
- Post storage areas with a
list of chemicals and quantities stored and notify the
fire department about storage.
C)
Mixing/Loading
- Review the label before
opening the container to ensure familiarity with current
use directions.
- Exercise care and caution
during mixing and loading.
- Replace pour caps and
close bags or other containers immediately after use.
- Mix chemicals and clean
equipment only where possible spills would not enter
streams, lakes or ponds.
- Chemicals should not be
applied where stream pollution is likely to occur through
aerial drift.
- Use a spray device capable
of immediate shutoff.
D)
Application
- Refer to label directions
before making a pesticide application.
- Check all application
equipment carefully, particularly for leaking hoses and
connections and plugged or worn nozzles. Calibrate spray
equipment periodically to achieve uniform distribution
and rate.
- Apply pesticides under
favorable weather conditions. Never apply a pesticide
when there is a likelihood of significant drift.
- Always use pesticides in
accordance with label instruction, and adhere to all
Federal and State policies and regulations governing
pesticide use.
E)
Cleanup and Disposal
- Before disposal,
containers should be rinsed as described in equipment
cleanup.
- Cleanup should be in a
location where chemicals will not enter any stream, pond,
or where stream pollution might
occur.
- Rinse empty pesticide
containers and mixing apparatus as many times as needed.
This flushing should be applied in spray form to the
treated area, NOT into the ground near streams.
- Dispose of pesticide
wastes and containers according to federal and state
laws. Some pesticide wastes are specifically identified
as hazardous wastes by law and must be handled and
disposed of in accordance with hazardous waste
regulations. For more information about proper management
of waste pesticides, contact the Department of Health,
Environmental Health Administration.
Other
chemicals
Improper storage and handling of oil products and fuel can
be a water quality hazard. Improper disposal of oil or fuel
can contaminate ground water and seep into streams. The
following are recommended:
- Locate facilities away
from streams and be prepared to clean up spills.
- Know and comply with
regulations governing the storage, handling, application
(including licensing of applicators), and disposal of
hazardous substances.
- Do not transport, handle,
store, load, apply or dispose of any hazardous substance
or fertilizer in such a manner as to pollute water
supplies or cause damage or injury to land, including
humans, desirable plants and animals.
- Do not store, mix, or
rinse hazardous substances or fertilizers within the
streamside management zone or where they might enter
streams or waterways.
- Develop a contingency plan
for hazardous substance spills, including cleanup
procedures.
- Report all spills to the
Department of Health, Environmental Health
Administration.
4.0
Streamside Management Zone (SMZ)
The Special Management Zone (SMZ) is a specific area
associated with a stream, lake, wetland or other waterbody
that is designated and maintained during silviculture
operations. The purpose of the SMZ is to protect water
quality by reducing or eliminating forestry related ouputs,
i.e. sediment, nutrients, logging debris, chemicals, and
water temperature fluctuations that can adversely affect
aquatic communities. SMZs provide shade, streambank
stability and erosion control, as well as detritus and woody
debris which benefit the aquatic ecosystem in general. In
addition, the SMZ is designed to maintain certain forest
attributes that will provide specific wildlife habitat
values. Snags, den and cavity trees as well as mast
producing trees, left in the SMZ, are necessary to meet
habitat requirements for certain wildlife.
The SMZ has specific criteria, that defines operational
restrictions and special management objectives. In addition,
the SMZ has a specific width which is based on the size and
type of waterbody involved.
A Streamside Management Zone (SMZ) is an area covered with
vegetation or ground cover on both sides of perennial,
intermittent streams and other bodies of open water, where
extra precaution is used in carrying out forest management
practices. The SMZ also provides shade and functions as a
buffer when fertilizers, pesticides, etc. are applied to
adjacent lands. For practical purposes, an SMZ must be wide
enough to protect water quality and stream characteristics.
Precaution is needed in carrying out forest management
practices in order to protect bank edges and water quality.
Determining the necessary width involves in part a judgement
factor based on reliable local experience.
SMZs should be used where: 1) water quality is impaired and
adjacent land use contributes to that degradation, 2) good
water quality exists and protection against potential future
impairment is desired, 3) streambank erosion is a concern,
4) wildlife habitat enhancement is desired, and/or 5)
silviculture practices are to be implemented, and 6) the
lower edge of cropland, grassland, or forest land is
adjacent to permanent or intermittent streams, or border
streams, rivers, ponds or intermittent or permanently
flooded, open-water wetlands.
SMZ benefits include the following:
|
(1) Shade -
Trees within the SMZs provide shade to maintain
cool water temperatures which aid in the spawing of
fish. Without trees and overhanging shrubs, stream
temperatures would increase during the summer. Some
fish species and aquatic organisms would then be
unable to live in the streams. In the summer, water
from shaded streams eventually flows into larger
bodies of water and helps maintain its fish and
aquatic life by keeping these waters cool all the
way downstream.
(2) Food - Leaves and insects drop into
streams from overhanging trees and shrubs. In fact,
90% of the food in the forested streams comes from
bordering vegetation.
(3) Protection of Streambanks - Many
streambanks are stabilized by streambank trees.
They anchor banks and prevent erosion during
periods of high water. Removing trees and shrubs
and substituting shallow rooted grasses can lead to
streambank collapse and stream sediment. Bank
overhang is created by stream flows undercutting
the stream bank and tree roots. Fish can rest, hide
from predators, and feed in these protected
areas.
(4) Flooding - Healthy SMZs stabilize
floodplains. During times of high water, SMZs
reduce the velocity of floodwaters. Their dense
vegetation and deep humus slow down racing waters.
Forest floodplains suffer less damage when SMZs are
protected during harvesting activities.
(5) Recreation - The recreational activities
that we enjoy in and around streams are many. This
includes swimming, fishing, camping, hunting, and
backpacking to name a few.
(6) Timber Production - For those who grow
and harvest trees, the fact is that trees often
grow best in SMZs. Trees respond to those deep,
fertile, and moist soils. Logging activities should
not be eliminated within SMZs but modified to
insure that stream channels and banks are protected
from disturbance. SMZs are not timber harvest "keep
out" zones, but there are locations where timber
harvesting activities must be modified to protect
the many benefits mentioned above.
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Recommendations
SMZs should be
maintained along all perennial streams or where forest
disturbances occur and surface runoff will carry sediment
loads. SMZs should be maintained around streams, ponds,
perennial flowing natural springs, and all springs and
reservoirs serving as domestic water supplies. The following
best management practices are recommended:
- The width of SMZs should
be determined depending on the following conditions:
slope of land adjacent to stream, soil erodibility,
precipitation, knowledge of particular area, sensitivity
of stream, etc. These factors can be obtained from soil
maps, on-the-ground evaluation and measurements, weather
data, etc.
- SMZs should be designed on
a case-by-case basis. Most important is that SMZs be
consistent with stream characteristics and wide enough to
protect water quality.
|
Soil
Type
|
Percent
Slope
|
SMZ Width
(each side)
|
|
Slightly
erodible
|
0-5 %
|
35
ft.
|
|
Slightly
erodible
|
5-20
%
|
35-50
ft.
|
|
Slightly
erodible
|
20%+
|
50-160
ft.
|
|
Erodible
|
0-5
%
|
35-50
ft.
|
|
Erodible
|
5-20
%
|
80 ft.
minimum
|
|
Erodible
|
20%+
|
160'
minimum
|
Table 1. Recommended Widths for Streamside Management
Zone
[NOTE: Please contact your local Natural
Resources Conservation Service office to determine the
erodibility factor of the soil before determining the
proper width of the
SMZ.]
- On relatively flat terrain
(0-5%) on slightly erodible soils, the width of an SMZ
should be at least 35 feet wide on each side of a
stream.
- On relative flat terrain
(0-5%) on erodible soils, the SMZ width should range
between 35 to 50 feet on each side of a stream.
- On slightly erodible soils
with slopes ranging between 5 and 20 percent, the SMZ
width should range between 35 to 50 feet wide on each
side of a stream.
- On erodible soils with
slopes ranging between 5 and 20 percent, the SMZ width
should range between 50 to 160 feet on each side of a
stream.
- On slightly erodible soils
with slopes exceeding 20 percent, the SMZ width should be
at least 80 feet on each side of a stream.
- On erodible soils with
slopes exceeding 20 percent, the SMZ width should be a
minimum of 160 feet on each side of a stream.
- Partial harvesting is
acceptable. A minimum of 50% of the original crown cover
or 50 square feet of basal area per acre, evenly
distributed, should be retained in the SMZ. This may be
adjusted to meet on-site conditions.
- Clearcutting is always
prohibited within the SMZ.
- Designate SMZs to provide
stream shading, soil stabilization, sediment and water
filtering effects, and wildlife habitat.
- Strive to protect the
forest floor and understory vegetation from unnecessary
damage. Do not remove (harvest) trees from banks, beds or
slopes if it will destablilize the soil. Trees on the
south and west banks provide the most critical shading of
water.
- Access roads should cross
perennial or intermittent streams at or near a right
angle.
- Drainage structures such
as ditches, cross drain culverts, water bars, rolling
dips, and broad-based dips should be used on all roads
prior to their entrance into an SMZ to intercept and
properly discharge runoff waters.
- SMZs may be desirable on
intermittent streams for large drainage areas where
wildlife is a major landowner concern or for other
reasons.
5.0
Fencing
- Fencing out livestock,
pigs, and other animals in certain areas will help to
prevent water quality degradation of streams, protect
threatened and endangered plants, reduce soil compaction
and maintain soil productivity. Fencing is applicable
where desired forest reproduction, soil hydrologic
values, existing vegetation, aesthetic values, and
recreation are prevented or damaged by these animals.
- Pastures should be fenced
separately from woodlands. Consider maintenance as well
as ease of construction when planning a fence location.
By taking advantage of natural barriers such as cliffs,
the cost of animal exclusion can be reduced. Also
consider use of fences to protect vegetation that
provides wildlife food and cover.
- Fences should be permanent
stock fences built in accordance with good construction
principles and workmanship.
6.0
Wildfire Damage Control and Reclamation/Prescribed
Burn
The prevention, control, and extinguishment of all wildfires
on grass, brush, and watershed lands and the implementation
of a prescribed fire program is a desirable goal. Where
wildfires do occur, the first and foremost concern is to
control the fire and limit the damage. Fire suppression
activities can add to the problem of water quality
protection.
The loss of vegetative cover, destruction of soil-holding
feature of root masses, the exposure of bare mineral soil,
is a combination that makes the area burned a highly
erodible one. The effects of suppression efforts and
equipment operations necessary to control and stop the fire
can magnify the erosion problem.
The following are best management practices for wildfire
control and reclamation:
- The first and foremost
concern in wildfire control is to prevent harm or damage
to people and property. Fireline best management
practices should incorporate minimum impact strategies,
which meet land and resource management objectives.
- Areas with bare mineral
soils should be revegetated and areas where vegetative
cover has been killed or severely degraded should be
regenerated with plant species appropriate for the soil
conditions.
- First priority for
revegetation/reforestation should be given to banks of
surface water bodies so that the SMZ is
reestablished.
- Firelines should be
stabilized and, if necessary, revegetated. Erodible areas
altered by suppression equipment activities should be
repaired and revegetated as necessary.
- Access road surfaces
should be repaired and stabilized as necessary.
- Whenever possible, avoid
using fire suppression chemicals over watercourses and
prevent their runoff into watercourses. Do not clean
application equipment in watercourses or locations that
drain into watercourses.
- Provide advance planning
and training for firefighters that considers water
quality impacts when fighting wildfires. This can include
increasing awareness so direct application of fire
suppression chemicals to waterbodies is avoided and
firelines are appropriately placed.
- Include rehabilitative
practices as part of suppression and post-suppression
tactics and strategies to mitigate non-point source
pollution.
6.1
Fireline Construction and
Maintenance
Fireline construction and maintenance is an essential part
of forest and other land management activities. It deals
with site preparation burning, prescribed burning, and
wildfire defense and control. A number of control practices
can be implemented during fireline construction to prevent
unnecessary erosion. Periodic inspection and proper
maintenance can prevent potential erosion on established
firelanes. The following are best management practices for
fireline construction and maintenance:
- Firelines should be
constructed on the perimeter of the burn area and along
the boundary of the Streamside Management Zone. The
purpose of protecting the Streamside Management Zone from
fire is to safeguard the filtering effects of the litter
and organic matter.
- Firelines should follow
the guidelines established for logging trails and skid
trails with respect to waterbars and wing ditches, and
should be only as wide and as deep needed to permit safe
prescribed burns or fire suppression needs.
- Firelines which would
cross a drainage should be turned parallel to the stream
or have a wing ditch or other structure allowing runoff
in the line to be dispersed rather than channeled
directly into the stream.
- All firelines should be
assessed after the fire is controlled for appropriate
stabilization, and if necessary, proper rehabilitation
should be done while equipment and people are in
place.
6.2
Prescribed Burn
- Intense prescribed fire
for site preparation shall be conducted only if it
achieves desired results with minimum impacts to water
quality.
- Burning on steep slopes or
highly erodible soils should be conducted when they are
absolutely necessary and should follow carefully planned
prescriptions.
- Carefully plan burning to
adhere to time of year, weather, topography, and fuel
conditions that will help achieve the desired results and
minimize impacts on water quality. With proper planning,
prescribed fires should not cause excessive sedimentation
due to the combined effect of removal of canopy species
and the loss of soil-binding ability of the subcanopy and
herbaceous vegetation roots, in streamside vegetation,
small ephemeral drainages, or on very steep slopes.
- Site preparation burning
creates the potential for soil movement. Burning in the
SMZ reduces the filtering capacity of the litter. All
efforts should be made to plan burns to minimize impacts
on the SMZ.
- All bladed firelines, for
prescribed fire and wildfire activities, should be built
so as to minimize erosion. If necessary, the firelines
should be stabilized with water bars and/or other
appropriate techniques to control excessive sedimentation
or erosion of the fireline. Include any erosion control
practices in the construction of firelines.
7.0
Reforestation
Reforestation refers to those operations undertaken to
establish a new forest. Site preparation, for the purpose of
forest regeneration, is a basic silvicultural tool where for
competing vegetation and reduction of logging debris are
necessary. Common site preparation techniques include,
manual, mechanical, fire, and herbicides.
Regeneration includes hand and machine planting and direct
seeding. Since hand planting and direct seeding pose no
water quality problems, BMPs are not necessary. Some mineral
soil exposure does occur with machine planting and BMPs are
offered.
- Sites should receive the
minimum preparation necessary to successfully control
competing vegetation and establish a desirable timber
stand. In general, the more intensive the treatment, the
more concern for water quality.
- When working on slopes,
mechanical operations such as ripping, shearing, etc.,
should follow contours.
Hand planting, direct
seeding or natural regeneration should be used on protected
areas adjacent to streams or on slopes too steep to machine
plant.
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