Nonfarm Erosion Control Chapter 7 Nonfarm Erosion Control

Introduction Soil is also disturbed by home building, industrial expansion, urban construction, highway construction, and many other nonfarm activities Daily, as many as 8,000 acres of U.S. farmland are converted to nonfarm use Cont.

Introduction Millions of acres of land are disturbed annually by strip mining for coal and other resources As new highways are constructed and old ones are widened, moved, or repaired, millions of miles of road banks are subject to water-caused erosion

Controlling Nonfarm Erosion CAUSES Construction Drainage ways drastically changed Concrete or asphalt Runoff problem severe Sedimentation or gullying Expensive control practices

Mechanical Erosion Controls DIVERSION DITCHES OR BERMS Collects the runoff Typically earth structures Runoff to an outlet Ditch is dug out of the ground Berm is mounded

Mechanical Erosion Controls WATERWAYS Collect excess soil water Rock-lined or concrete-lined Conducted away quickly Slope is very steep Steep diversion waterway Water chute

Mechanical Erosion Controls SEDIMENT BASIN Like a small pond Designed to be filled up Catches excess runoff Sediment settles Temporary structures Used during construction

Mechanical Erosion Controls BANK PROTECTION Extra efforts to stabilize banks Seed, mulch or hydroseeding Concrete or stone walls Jute matting Wooden strips placed across the slope Chemical binding

Mechanical Erosion Controls TERRACING Solution on long, steep banks Breaks into shorter slopes Disposal areas Grassed or lined waterway Chute Wooded area Storm sewer

Mechanical Erosion Controls DOWNSTREAM RUNOFF Very large construction projects Large factories Normal stream flow may be greatly increased Flooding Measures may be needed downstream

Vegetative Erosion Controls LAWN Most common technique Nonfarm sites Seedbed Sprigging Plugging Sodding

Vegetative Erosion Controls SOD Quick development Heavy growth of grass Squares or strips Living layer Produced on a sod farm Soil must be well prepared

Vegetative Erosion Controls MULCH Holds grass seed in place Maintains surface moisture Protects from erosion Silage-like slurry Chemical bonding

Vegetative Erosion Controls GROUND COVERS Low-growing shrubs, Vines, or other plants Used much like grass Combined with mulching Increase protection

Vegetative Erosion Controls TEMPORARY COVER CROPS Construction sites Protect an area temporarily Construction delays Many plants can only start at certain times

Highway Erosion Control SPECIAL PROBLEMS Highway surfaces Practically waterproof As level as practical Exposed banks Erosion damage Sediment

Strip Mining Operations PROBLEMS Large increase Appalachia Very steep slopes High-velocity water

Strip Mining Operations VIRGINIA COAL MINES Spoil Drainage and erosion-control system Two-year period Land must be reclaimed Bond is forfeited with noncompliance Government regulations to be followed

Summary The impact of falling raindrops must be absorbed by something other than the soil surface, and the speed of the runoff must be kept under control Because almost all construction disturbs and reshapes the land, it exposes the soil to greatly accelerated erosion Cont.

Summary Mining operations and highway construction present the same or even more extreme problems of erosion The best solution to the erosion problem is almost always a combination of both vegetative and mechanical measures