Soil Erosion By Water - Causes and Mitigation
Transcript of Soil Erosion By Water - Causes and Mitigation
![Page 1: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/1.jpg)
Soil Erosion By Water -Causes and Mitigation
Jerry J. DaigleState Soil Scientist
Bradley A. StickerAsst. State Conservation Engineer
USDA - Natural Resources Conservation Service
Stormwater Phase II
![Page 2: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/2.jpg)
Soil - Ecological and Hydrological Resourcesupports plant growthprovides waterprovides nutrientsprovides mechanical supportfilters before enteringsurface waterfilters beforeenteringaquifers
Stormwater Phase II
soil FiltersBuffers
Degrades
Detoxifies
Immobilizeswatertable
![Page 3: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/3.jpg)
Soil - Controls the fate of precipitation
controls what part infiltratescontrols what part runs offstores water at depths available for plantstransmits water to underlying materials
Stormwater Phase II
![Page 4: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/4.jpg)
Erosion
Erosion is a process of detachment and transport of soil particles by erosive agents
Ellison, 1944
Stormwater Phase II
Sediment LoadSediment Transport
Detachment
Soil
Rain
RunoffSoil
Infiltration
![Page 5: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/5.jpg)
Deposition:
Soil
Sediment LoadSediment Transport
Deposition
Reduces the sediment loadAdds to the soil massLocal deposition
Surface roughness depressions
Remote depositionConcave slopeStripsTerraces
Stormwater Phase II
![Page 6: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/6.jpg)
ErosionErosive Agents
Raindrop impact
Overland flow of surface runoff from rainfall
Stormwater Phase II
![Page 7: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/7.jpg)
Stormwater Phase II
Erosion is a ConcernDegrades soil resource
Reduces soil productivityReduces soil organic matterRemoves plant nutrients
Causes downstream sedimentationProduces sediment which is a pollutantProduces sediment that carries pollutants
![Page 8: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/8.jpg)
Types of Erosion
Stormwater Phase II
Geologic
natural process
humans can accelerate
![Page 9: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/9.jpg)
Types of Erosion
Stormwater Phase II
Raindrop or Splash
high detachment capacity
low capacity for transport
![Page 10: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/10.jpg)
Types of Erosion
Stormwater Phase II
Interrill (sheet)low detachment capacityhigher capacity for transport
![Page 11: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/11.jpg)
Types of Erosion
Stormwater Phase II
Rillsmall channels <1 foot deeplow detachment capacityhigher capacity for transport
![Page 12: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/12.jpg)
Types of Erosion
Stormwater Phase II
Gullyfrom concentrated storm water flowremoves higher volumes per unit area
![Page 13: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/13.jpg)
Types of Erosion
Stormwater Phase II
Stream Channelhigh volume peak flows may erode streambanks and channels
removes portions of the land surface above and adjacent to the bankcan deliver large volumes of sediment directly into the stream
![Page 14: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/14.jpg)
Types of Erosion
Stormwater Phase II
Mass movement (Landslip)
slides - shear along specific surfaces
flows - viscous,fluid movement
![Page 15: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/15.jpg)
Factors affecting erosion
Stormwater Phase II
Topographyslope gradientoverland flow slope lengthlength of eroding portionsslope shape
Land usecover managementsupporting practices
Climaterainfall - amountrainfall - intensity
Soiltexturemoisturesurface roughness
![Page 16: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/16.jpg)
Simple Uniform Slope
Soil LossSedimentYield
Stormwater Phase II
Sediment Yield = Soil Loss
![Page 17: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/17.jpg)
Stormwater Phase II
Complex Slope
Soil loss
Remote deposition
Sediment yield
Sediment Yield = Soil Loss - Deposition
![Page 18: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/18.jpg)
Complex Slope
Soil loss
Remote deposition
Sediment yield
Soil loss
Stormwater Phase II
Sediment Yield = Soil Loss - Deposition
![Page 19: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/19.jpg)
Local Deposition
Random Roughness:
Ridges-Furrows:
Stormwater Phase II
Sediment Yield = Soil Loss - Deposition
![Page 20: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/20.jpg)
Stormwater Phase II
Deposition
Transport capacity = sediment load
Sediment production less than transport capacity
Deposition because sediment production exceeds transport capacity
Relation of deposition to transport capacity and sediment load on a complex slope
HillslopeTransport capacity
Sediment load
![Page 21: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/21.jpg)
Stormwater Phase II
How Deposition at a Grass Strip Affects Sediment Characteristics
17Primary sand524Large aggreg.
1436Small aggreg.5824Primary silt225Primary clay
After (%)Before (%)Particle class
SDR = 0.2Note how deposition enriches sediment in fines
![Page 22: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/22.jpg)
Stormwater Phase II
Basic PrinciplesSediment load accumulates along the slope because of detachmentTransport capacity is function of distance along slope (runoff), steepness at slope location, cover-management, storm severity (10 yr EI)Deposition occurs where sediment load becomes greater than transport capacity
![Page 23: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/23.jpg)
Stormwater Phase II
Prevention and Reductionfit development to the terraintime disturbance to minimize soil erosionretain existing vegetation whenever feasiblevegetate and mulch denuded areasdivert runoff away from denuded areasminimize length and steepness of slopeskeep runoff velocities lowprepare drainage ways and outlets to handle flowtrap sediment on-siteinspect and maintain control measures
![Page 24: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/24.jpg)
Stormwater Phase II
Soil loss
Remote deposition
Soil loss
Sediment yield
Remote deposition
Soil loss Remote deposition
Terraces
![Page 25: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/25.jpg)
Stormwater Phase II
Strips
Soil lossRemote deposition
Soil loss
Sediment yield
Remote deposition
![Page 26: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/26.jpg)
Stormwater Phase II
Dense grass
Erodible soil surface
Deposition region
Deposition ends where transport capacity = sediment load
Transport capacity
Sediment load
Relationship of Deposition to Transport Capacity and Sediment Load for a Grass Strip
![Page 27: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/27.jpg)
Stormwater Phase II
Why worry about erosion at construction sites?
![Page 28: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/28.jpg)
Stormwater Phase II
Sediment Laden Runoff
![Page 29: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/29.jpg)
Stormwater Phase II
Sediment in Drainage Channels
![Page 30: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/30.jpg)
Stormwater Phase II
Construction Site BMPs
Need to address soil erosion and sediment transportMay be structural and/or non-structural Should be applied according to a plan developed prior to construction start
![Page 31: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/31.jpg)
Stormwater Phase II
Types of Construction Site BMPsErosions control BMPs
prevent the detachment of soil particles and subsequent suspension and transportation in runoff waterfirst and best line of defense
Sediment control BMPs remove a portion of the suspended soil particles from runoff
![Page 32: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/32.jpg)
Stormwater Phase II
Erosion Control BMPsMinimize disturbed areas and preserve existing vegetationTemporary and permanent vegetative establishment of disturbed areasMulching disturbed areasCovering stockpilesStabilized construction site entrancesDivert runoff from disturbed areasVarious combinations of all of the above
![Page 33: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/33.jpg)
Stormwater Phase IIMulching
Seed prior to mulching
Hay or straw @ 1 1/2 to 2 tons per acre
Mechanically anchor with netting or crimper
Blowing Straw Mulch
![Page 34: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/34.jpg)
Stormwater Phase IICommercial Mulch Matting
Wide variety of types for various applications
Apply in accordance with manufacturer’s recommendations
![Page 35: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/35.jpg)
Stormwater Phase II
Commercial Mulch Matting
![Page 36: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/36.jpg)
Stormwater Phase II
Vegetative EstablishmentEstablish vegetation as soon as practical after disturbanceNRCS FOTG Standard - Critical Area Planting (Code 342)
Use appropriate seed mix for time of yearTest soilFertilize and lime according to soil test
![Page 37: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/37.jpg)
Stormwater Phase II
Vegetative Establishment
![Page 38: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/38.jpg)
Stormwater Phase II
Sediment Control BMP’s
Second line of defenseRequire proper installationMaintenance is crucial through out project life
![Page 39: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/39.jpg)
Stormwater Phase II
Sediment Control BMP’s
Silt fencesCheck damsDrain inlet protectionSediment retention basinsOther sediment retention devices
![Page 40: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/40.jpg)
Stormwater Phase II
Improperly Installed Silt Fences
![Page 41: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/41.jpg)
Stormwater Phase IIProperly Installed Silt Fences
![Page 42: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/42.jpg)
Stormwater Phase II
Open Top Gabion Check Dams
![Page 43: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/43.jpg)
Stormwater Phase IITypical Drawing of Hay Bail Check Dams
![Page 44: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/44.jpg)
Stormwater Phase II
Drain Inlet ProtectionRequires monitoring and maintenance
![Page 45: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/45.jpg)
Stormwater Phase IITypical Drawing of Drain Inlet Protection
![Page 46: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/46.jpg)
Stormwater Phase IITypical Drawing of Drain Inlet Protection
![Page 47: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/47.jpg)
Stormwater Phase IITypical Drawing of Drain Inlet Protection
![Page 48: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/48.jpg)
Stormwater Phase II
Sediment Basins
Drainage areaRetention timeTemporary storage volume
![Page 49: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/49.jpg)
Stormwater Phase IITypical Drawing of Sediment Retention Basins
![Page 50: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/50.jpg)
Stormwater Phase IISediment Retention Basins
![Page 51: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/51.jpg)
Stormwater Phase IITypical Drawing of Sediment Retention Basins
![Page 52: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/52.jpg)
Stormwater Phase IICommercially Available Sediment Retention Devices
![Page 53: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/53.jpg)
Stormwater Phase II
Available ResourcesUSDA Natural Resources Conservation Service
www.usda.nrcs.gov
International Erosion Control Associationwww.ieca.org
![Page 54: Soil Erosion By Water - Causes and Mitigation](https://reader030.fdocuments.us/reader030/viewer/2022013015/61d0a0f61821235177763d7c/html5/thumbnails/54.jpg)
Stormwater Phase II
Our Soilis
Our Strength