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Vegetative Practices for Erosion and Sedimentation Control. Level IA: Fundamentals Seminar Education and Training Certification Requirements for Persons Involved with Land Disturbing Activities. Issued May 2009. Objective Understand vegetative measures Their role
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Vegetative Practices for Erosion and Sedimentation Control Level IA: Fundamentals Seminar Education and Training Certification Requirements for Persons Involved with Land Disturbing Activities Issued May 2009
Objective • Understand vegetative measures • Their role • How selected, installed, and maintained
Key Points • Excess soil erosion is not inevitable • A system of measures is needed • Vegetative measures provide many benefits • Site characteristics determine species selection • Establishment requires many components • Proper maintenance is required
Erosion and Sediment Control • Very important to all of us • All benefit if successful • If not done properly: • polluted streams • additional problems onsite and offsite • project delays • stop work orders • increased construction costs • $$$ for cleanup • additional time required to re-do measures
Erosion or Sediment Control? Soil Erosion Soil particles are detached and transported. • Occurs on all land • Greatest losses are from bare soil • Vegetative cover reduces soil loss Sedimentation Eroded soil is transported and deposited. • Sediment is #1 non-point source pollutant in U.S. • Structural measures trap sediment
Effective E&SC requires aSystem of Measures • One measure does not solve all of our erosion and sediment control problems • Vegetative, structural, andmaintenancemeasures are needed • Each has an important role • They complement and aid each other
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
Construction Sites are inhospitable for vegetative growth • Topsoil is removed • Steep slopes • Low soil moisture • Low soil fertility • Acidic soils • Concentrated flow • Compacted soils Intensive treatment is needed. Pasture planting methods are not effective.
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
Buffer Zone • Undisturbed or planted vegetative strip • General Buffer – surround sites • Vegetated Stream Buffer – border streams Bf • Filter sediment & other pollutants • Reduce runoff velocities • Stabilize stream banks • Provide flood protection • Improve fish & wildlife habitat • Reduce construction noise • Reduce wind erosion • Improve aesthetics
Buffer Specifications are Based on Site Conditions • Purpose • Topography • Watershed size • Stream size • Type of stream • Trout stream • Warm water stream • Maintenance
Cs Coastal Dune Stabilization (with Vegetation) • Planting vegetation on • denuded, constructed, • or re-nourished dunes • Permits (local/state/federal) • Sand fences • Fertilization • Planting with native species • Irrigation • Maintenance • Protection from traffic
New Sand Fence 1 Year Old Sand Fence Sand fences help build higher dunes by trapping sand.
Sea Oats Cordgrass Cross Walk
Ds1 Disturbed Area Stabilization (With Mulching Only) • Applying plant residues or other suitable materials to thedisturbed 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
Disturbed Area Stabilization (With Mulching Only) • On areas where vegetation has been removed and soil protection is needed • Temporary cover needed: • Final grading not complete • Area will be disturbed again • 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
Per the “Manual for E&SC in Georgia” • Ds1 - Mulching Only • On exposed areasleft idle for 14 days • Apply at theappropriate depth • Must beanchored • Maintain cover on90% or moreof the soil surface • Can be used alone forup to 6 months
Pine Bark Cypress mulch Pine Straw Blanket
Disturbed Area Stabilization (With Temporary Seeding) Ds2 • Establishing fast growing vegetation for seasonal soil protection • Reduce soil erosion • Reduce runoff • Increase infiltration • Improve aesthetics • Improve soil quality • Improve wildlife habitat Browntop millet
Required Temporary Seeding • Rough graded areas • Diversions • Sides of temporary basins • Stockpiled soil • Temporary dams
Ds2 Temporary Seeding Components • grading & shaping • lime • fertilizer • seedbed preparation • proper plant selection • quality seed • proper planting techniques (rates/timing/depth) • mulch • irrigation
Per the “Manual for E&SC in Georgia” • Ds2 - Temporary Seeding • On all exposed areasleft idle for 14 days • Maintain cover on90% or moreof the soil surface • Can be used alone forup to 6 months • Permanent vegetation will be used if area is to beundisturbed formore than 6 months
Ds2 – Plant Selection • Germinate quickly • Adequate cover • Noncompetitive 90 % cover ?
Regional variations: Climate & Soils
Soils make a difference Tifton Cecil They vary across the state. They vary on a site.
Regional differences inthe “Manual” -approved species -rates -combinations -planting dates
Common Plants Used for Temporary Cover Warm season annualsCool season annuals -brown top millet -rye -pearl millet -ryegrass -sudan grass -wheat Warm season perennialsCool season perennial -common bermuda -tall fescue -weeping lovegrass
Disturbed Area Stabilization (with Permanent Vegetation) Ds3 Planting perennial vegetation (grasses, legumes, vines, shrubs, and trees) on exposed areas for: 1. Final permanent stabilization & 2. Rough graded sites for >6 months
Ds3 Permanent Vegetation Plans are based on soil and site conditions. • Site location • Soil characteristics • Topography • Concentrated water flow • Planned land use • Soil fertility • Soil pH
Ds3 Planned Components Grading and shaping Inoculants Liming Planting method Fertilization Seeding depth Seedbed preparation Mulch Species selection Anchoring mulch Seeding rates Irrigation Seeding dates Maintenance
Seedbed Preparation • Provides good growing medium for roots • critical for good plant growth • a good root system is needed in order to have effective vegetative cover • Incorporates lime and fertilizer 4 to 6 inches in depth • Not normally needed for hydroseeding
Soil Tests and Nutrient Management • Determines soil acidity • Determines soil fertility • Provides ample nutrients for plants • Protects the environment by reducing nutrient losses
pH Scale Neutral 1 2 3 4 5 6 7 8 9 10 11 12 13 14 More AcidMoreBasic (10 fold difference in acidity from one number to the next)
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
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 Hydroseeding- apply after cover is present 1. after straw/hay mulch is applied, 2. with topdressing, or 3. with 2nd year fertilizer
Fertilization 1. Initial – immediately before or at planting 2. Topdressing – 6 to 8 weeks after planting 3. 2nd year – the year after planting 4. Maintenance – each year • Fertilize based on target species • Don’t “plant it and forget it”
Fertilizer content Q. What do the numbers mean? A. The fertilizer analysis
Fertilizer Analysis 5% Nitrogen 10% Phosphorous 15% Potassium This 50 LB bag contains 30% plant food (15 LB) and 70% filler.
Fertilizer Selection is based on needs of the target species For legumes Initial fertilizer Ammonium nitrate (N topdressing for grasses)
Fertilizer for Grasses TimingAnalysis First YearN, P, K TopdressingN Second Yr. N, P, K MaintenanceN, P, K
Fertilizer for Grass/Legume Mixtures TimingAnalysis First YearN, P, K TopdressingN Second Yr. P, K MaintenanceP, K • The desired species are legumes • Legumes get N from bacteria
Consider Native Grasses • Well adapted • Extensive root system • Attractive • Excellent for wildlife • Low maintenance • Little bluestem • Broomsedge bluestem • Reed canary grass • Eastern gama grass • Big bluestem • Indian grass • Switchgrass • Virginia wildrye
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
Pure Live Seed (PLS) Calculations Step 1:Get information from the 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