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 ?