Download - Level IB: Advanced Fundamentals Seminar Vegetative Practices for Erosion and Sedimentation Control
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Level IB: Advanced Fundamentals Level IB: Advanced Fundamentals SeminarSeminar
Vegetative Practices for Erosion Vegetative Practices for Erosion and Sedimentation Controland Sedimentation Control
Level IB: Advanced Fundamentals Seminar
Education and Training Certification Requirements for Persons Involved
with Land Disturbing Activities
Issued May 2009
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Objectives
• Review the vegetative measures
• Determine if planned measures are properly applied and maintained
• Review maintenance techniques
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Key Points
• Excess erosion is not inevitable on construction sites
• Vegetation can reduce soil erosion
• Evaluation of applied vegetative measures– Identify commonly used plants – Estimate the % cover (mulch and vegetation)– Determine if measures are being maintained
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Benefits of Vegetation in E&SC• Intercepts raindrops
– Reduces detachment of soil particles– Results in less soil erosion
• Slows runoff– Cleans runoff– Reduces runoff– Increases water infiltration– Increased soil moisture aids plant growth
• Protects structures, rivers, streams, and ponds• Reduces maintenance of structural measures
– Reduced deposition in sediment basins & other structures• Improves aesthetics, soil quality, and wildlife habitat
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Construction Sites are inhospitable for vegetative growth
Intensive treatment is needed. Pasture planting methods are not effective.
• Topsoil is removed
• Steep slopes• Low soil moisture • Low soil fertility• Acid soils• Concentrated flow
• Compacted soils
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Vegetative Practices “Manual for Erosion and Sediment Control in Georgia”
• Bf Buffer Zone• Cs Coastal Dune Stabilization • Ds1 Mulching Only• Ds2 Temporary Seeding• Ds3 Permanent Seeding• Ds4 Sodding• Du Dust Control • Mb Matting and Blankets• Pm Polyacrylamide• Sb Streambank Stabilization• Tb Tackifiers and Binders
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Buffer ZoneUndisturbed or planted vegetative strip
•General Buffer – surround sites•Vegetated Stream Buffer – border streams
•Filter sediment & other pollutants•Reduce runoff velocities•Stabilize stream banks•Provide flood protection •Improve fish/wildlife habitat•Reduce construction noise •Improve aesthetics
Bf
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Coastal Dune Stabilization
(with Vegetation)Planting vegetation on denuded, constructed, or re-nourished dunes
•Fertilization•Planting with native species•Irrigation•Sand fences•Maintenance•Permits (local/state/federal)•Protection from traffic
Cs
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Disturbed Area Stabilization (With
Mulching Only)Applying plant residues or other suitable materials to the disturbed soil surface
• Mulching without planting • Reduce runoff and erosion• Conserve moisture• Prevent surface compaction• Control undesirable vegetation• Modify soil temperature• Increase biological activity in the soil
Ds1
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• On areas where vegetation has been removed and soil protection is needed
• Temporary cover needed:1. Final grading not complete
– Area will be disturbed again
2. Not optimum season for vegetative establishment – Mulch is applied for seasonal protection
• Large amounts of mulch are required• Application rates are much higher than for seeded areas
Disturbed Area Stabilization
(With Mulching Only)
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Per the “Manual for E&SC in Georgia”
Ds1 - Mulching Only
•On exposed areas left idle for 14 days
•Apply at the appropriate depth
•Must be anchored
•Maintain cover on 90% or more of the soil surface
•Can be used alone for up to 6 months
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Disturbed Area Stabilization
(With Temporary Seeding)
Ds2Establishing fast growing vegetation for seasonal soil protection
•Reduce soil erosion•Reduce runoff•Increase infiltration•Improve aesthetics•Improve soil quality•Improve wildlife habitat
Browntop millet
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Required Temporary Seeding
• Many components
• Rough graded areas
• Diversions
• Sides of temporary basins
• Stockpiled soil
• Temporary dams
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Per the “Manual for E&SC in Georgia”
Ds2 - Temporary Seeding
•On all exposed areas left idle 14 days
•Maintain cover on 90% or more of the soil surface
•Can be used alone for up to 6 months
•Permanent vegetation will be used if area is to be
undisturbed for more than 6 months
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Common Plants used for Temporary Cover
Warm season annuals Cool season annuals-brown top millet -rye -pearl millet -ryegrass -sudan grass -wheat
Some fast growing perennials may also be used.Examples are: common bermuda and tall fescue
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Disturbed Area Stabilization (with Permanent Vegetation)
Ds3Planting perennial vegetation (grasses, legumes, vines, shrubs, and trees) on exposed areas
-Final permanent stabilization &
-Rough graded sites for >6 months
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Permanent Vegetation
Plans are based on site conditions.
• Site location• Soil characteristics• Topography• Concentrated water flow• Planned land use • Soil fertility• Soil pH
Ds3
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Components
Grading and shaping InoculantsLime Planting method Fertilizer Seeding depthSeedbed preparation Mulch Species selection Anchoring mulchSeeding rates IrrigationSeeding dates Maintenance
Ds3
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Seedbed Preparation
• Provides good growing medium for
roots to have good plant canopy, a
good root system is required• Critical for good plant growth• Incorporates lime and fertilizer 4 to 6 inches in
depth• Not normally needed for hydro-seeding
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Soil Acidity (or pH)
• Greatly affects plant growth
• Most Georgia soils are acidic
• Most plants used need a soil pH of 6.0 - 6.5
• Apply 1 – 2 T/A of agricultural lime (CaC03) prior to or during establishment– Maintenance applications are also needed
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Agricultural Lime• Does not move readily through the soil
• Can be lost in runoff
Conventional planting – apply immediately before seedbed preparation so it will be mixed into the soil
Hydro-seeding - apply after cover is present
1. after straw/hay mulch is applied, 2. with topdressing, or 3. with 2nd year fertilizer
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FertilizationInitial – immediately before or at planting
Topdressing – 6 to 8 weeks after planting
2nd year – the year after planting
Maintenance – each year
• Fertilize based on target species
• Don’t “plant it and forget it”
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Fertilizer content
Q. What do the numbers mean?
A. The fertilizer analysis
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Fertilizer Analysis
5% Nitrogen 10% Phosphorous 15% Potassium
This 50 LB bag contains 30% plant food (15 LB) and 70% filler.
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Fertilizer
Selection is based on needs of the target species
Ammonium nitrate
(N topdressing for
grasses)
Initial fertilizer For legumes
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Fertilizer for Grasses
Timing Analysis
First Year N, P, KTopdressing NSecond Yr. N, P, KMaintenance N, P,
K
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Fertilizer for Grass/Legume Mixtures
Timing Analysis
First Year N, P, KTopdressing NSecond Yr. P, KMaintenance P, K
• The desired species are legumes
• Legumes get N from bacteria
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Regional variations:
Climate&
Soils
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Species
PLS 1/ Seeding Rate2/
LB/AC Seed/LB Seed/Sq. Ft.
Common bermuda
10 1,800,000
410
Weeping lovegrass
4 1,500,000
140
Tall fescue
50 227,000
260
Bahia 60 166,000
230
Sericea lespedeza
60 350,000
480
1/ PLS = Pure Live Seed 2/ Seeding rate when seeded alone
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Seeding Rates for a Quality Stand
• Under-seeding reduces the stand• Over-seeding creates excessive demand for
moisture, nutrients, light, and space
More is not always better
More seed will not overcome poor planting techniques
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Seed Label
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Pure Live Seed (PLS) Calculations
Step 1: Get information from seed label: -tall fescue seed-95% purity -85% germination
Step 2: Calculate the PLS value of the seed:PLS = 0.95 x 0.85 = 0.81 or 81%
Step3: Calculate the seeding rate: 50 #/AC = 62 #/AC are needed 0.81
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Optimum planting dates for Warm Season Plants
Plant common bermuda and weeping lovegrass in the early spring:
April 1 - May 15
This permits germination, plant growth, and root
development prior to the hot and dry summer.
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Optimum planting dates for Cool Season Plants
Plant rye, ryegrass, and tall fescue in early fall:
September 1 - October 15
This permits germination, plant growth,
and root development prior to the
winter cold and spring drought.
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Some plants develop slowly and
companion plants are needed
Sericea lespedeza emergingin weeping lovegrass
Sericea lespedeza 2-3 years later
Other examples are bahia grass and crown vetch.
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Limit Seeding Rates of Companion Plants• Annuals are more vigorous and grow faster
• Compete for nutrients, moisture and space
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Cool Season Companion Plants
Rye is the best winter annual. It grows best on cold, acidic
soils.Use ½ BU/AC (28 LB).
Do not use ryegrass in seeding mixtures. It is too competitive.
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Mulch is very important!
Dry straw - 2 T/A
or
Dry hay - 2 ½ T/A
This will cover about 75% of the soil surface
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Disturbed Area Stabilization (with
Sodding)Establishes immediate cover with permanent sod
Effective on steep slopes & in concentrated flow areas
Components: soil preparation topsoil application lime fertilization anchoring (on slopes >3:1) irrigation maintenance
Ds4
Cimarron Valley Sod
Sod Solutions
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Dust ControlControlling surface and air movement of dust
Temporary– Mulch– Temporary plantings– Tackifiers/binders– Rough tillage– Irrigation– Barriers – Calcium chloride
• Permanent – Permanent vegetation and stone
Du
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• Protects young plants • Promotes plant establishment• Helps reduce erosion
-Temporary and permanent blankets-All must be approved by GDOT
Erosion Control Matting and
Blankets
MbProtective coverings used to establish permanent vegetation
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Mats and Blankets Required on:
• Slopes steeper than 2.5:1 and 10’ high or higher• Concentrated flow areas• Cuts and fills within stream buffers• Streambanks• Tidal shorelines• Other areas
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Blankets must be anchored. Start at top of slope and work down.
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Land application of anionic polyacrylamide as
temporary soil binding agent
• To reduce erosion from wind and water• When establishment of vegetation is not feasible• Site specific material• Repeat application if area is disturbed• Do not apply to surface water
Polyacrylamide (PAM)Pm
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Streambank Stabilization (using Permanent
Vegetation)Using native plants (such as black willow)
to maintain or enhance streambanks
Sb
Before After
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• Intensive planning is required• Combine with structural measures• Live stakes, joint plantings, live fascine,
brushmattresses, live cribwalls, branchpacking• ½ fertilizer at planting, ¼ when new growth is
2” tall, and ¼ about six weeks later • Labor intensive• Local/state/federal permits may be required
SbStreambank Stabilization
(using Permanent Vegetation)
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• Holds mulch in place
• Options in “Manual”
Tackifiers and Binders
TbUsed to anchor straw or hay mulch
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TopsoilingStripping, storing, and using
topsoil as topdressing prior toplanting perennial vegetation
• Better soil quality • Better water infiltration• Better root growth • Increased plant growth
Tp
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Inspections
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Visual observations
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Stream Buffers
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Where are the seeds?
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Lacking tackifier – damage from foot traffic
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Mulch not anchored
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Where are the blankets?
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These blankets were not applied correctly!
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Plant I.D. – Know the plants you work
with.
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Bahia
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Common bermuda
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Browntop millet
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Centipede Sod
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Rye
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Ryegrass
Winter-early spring
Late spring-summer
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Sericea lespedeza
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Tall fescue
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Weeping lovegrass
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Crabgrass
Is this an approved vegetative cover?
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USDA Plant Database
http://plants.usda.gov/
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Temporary cover or mulch needed?
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What is the % cover?
temporary cover
wheat straw
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How can we accurately estimate the % ground cover of mulch or vegetation?
Answer: The line-transect method is effective and is easy to use
1. Use a tape measure, cable,
string, or any other line that
has 100 equally spaced
beads, knots, or other
gradations. U. Neb. Lincoln
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2. Select an area that is representative• Avoid areas that appear different from the rest
of the field. • Select the area at random.
3. Stretch the line out across the area.
4. Anchor both ends & do not move the line.
5. Walk along the line, stopping at each mark.
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6. Look straight down at a single point
on each mark.
-The entire knot or mark is usually too large
-Look at the same point at each mark
U. Neb. Lincoln
74U. Neb.
Lincoln
7. Determine if each single point is above cover
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8. Count only those points that have a piece of residue or vegetation beneath them. To count, the cover must be large enough to intercept a raindrop, or about 3/32” (the size of a wooden pencil)
U. Neb. Lincoln
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9. Determine the % cover
When 100 points are observed, the number directly over cover will be the %. (If cover is under 90 points, there is 90% cover.)
If 50 points are observed, simply multiply the number directly over cover by 2 to get the %.(If cover is under 40 points, there is 80% cover.)
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10. Make at least 3 measurements. – For accuracy, use this process in 3 or more
representative areas of the site. – Average the measurements to obtain an
accurate estimate of the % cover.
11. Document your measurements.
For more information, visit this web site:http://ianrpubs.unl.edu/fieldcrops/g1133.htm
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Maintenance is important
Fertilizer and/or lime needed hereMany plants used are not native to our area
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Temporary cover
Yellowing shows N deficiency
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Fertilizer needed
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Nutrient deficiencies
NP
K
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Nutrient Deficiency Symptoms
• Not always clearly defined
• Can be masked by other factors
• Indicate severe nutrient starvation
• Rob plant performance before they appear
• Are called “hidden hunger”
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Agricultural lime
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Summary
1. Vegetation can reduce soil erosion.
2. Each measure has several components.
3. All measures require maintenance.
4. Inspectors should document deficiencies.
5. Deficiencies should be corrected immediately.
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Questions ?