Creek Retaining Wall Surge Stone Erosion Prevention

 Research Links

• Google: riprap on slope
• Google: riprap design
• Bioengineering/Riparian Restoration on Challenging Sites
• LOOSE RIPRAP PROTECTION Minnesota Technical Note 3 July 1989
• GravelShop: RipRap Calculator for 4-12"

Contact Notes

• Honey Creek Mine
• EFCC FAMILY  Current Limestone Price List
• Bessemer Concrete LLC

Surge Stone / Large RailRoad type Gravel specifications

INFORMATION

• 16 USD per ton
• Density: 1 ton = 0.83 cu yd / 1 cu yd = 1.2 ton
• Coverage: 0.62 cu yd covers 100 sq ft 2 inch deep
• Coverage: 1.54 cu yd covers 100 sq ft 5 inch deep
• Estimator: Coverage Calculate Rip Rap 2" – 4" – Gabion/Surge Stone

 

Per Loose RipRap Protection Minnesota 

G. Allowable Side Slopes. The stability of the riprap on the side slope of a channel
is dependent on the angularity of the rock. The more angular the rock, the higher the
angle of repose. The maximum (steepest) slope for riprap is recommended to be 2:1
(that is, two feet horizontally for every foot of vertical height). For small areas, such as
around existing culverts or transitions where slopes steeper than 2:1 cannot be avoided,
slopes up to 1:1 can be tolerated, provided the riprap thickness and size are increased.
Very angular rock must be used and carefully installed. The thickness shall be
increased by 10% for 1.5:1 side slopes and by 20% for 1:1 side slopes. The minimum
D50 that can be used on slopes steeper than 2:1 is 4 inches. This must be angular rock,
not rounded. 

 

 

 

———RipRap pile angle calculation————–

 

—From Slope foto #01—

x1,y1 = 1400,1600

x2,y2 = 4100,0

Slope = (1600-0) / 4100-1400   = 1600/2700 = 31     using bottom less sloped

x1,y1 = 3200,700

x2,y2 = 4100,0

Slope2 = 700 / 900 = 0.78   Absolute maximum slope of pile  => 38 degrees

—From Slope foto #02—

x1,y1 = 2500,1300

x2,y2 = 4100,0

Slope1 = 1300 / 1600 = 0.81   Absolute maximum slope of pile  => 39 degrees

 

—From Slope foto #03 & 4—

x1,y1 = 0,0

x2,y2 = 2900,1700

Slope1 = 1700 / 2900 = 0.58   Absolute maximum slope of pile  => 30 degrees

 

Current Cut Slope = 3/4 = 0.75  => 37 degrees  — Essentially at max slope here.

Modifying creek slope to 3/5 = 0.60  => 31 degrees => 1ft delta at top of cut