Soil Erosion

1
Soil Erosion
2
Grading Standards in the UDC

• The purpose of erosion control as stated in the
  UDC is to prevent or reduce the potential
  deposition of soil or sediment to the waters of
  the state and adjacent properties.
• The finished grade of the soil shall slope away
  from the dwelling at a rate of at least ½ inch
  per foot
• The graded slope away from the dwelling shall be
  at least a minimum distance of 10 feet, or to the
  lot line, whichever is less.

3
Controls Come First

• Land disturbing construction activities, except
  those activities necessary to implement erosion
  or sediment control practices, may not begin
  until the sediment control practices are in place
  for each area to be disturbed in accordance with
  the approved plan.

4

• A disturbed area shall be considered stabilized
  by vegetation when a perennial cover has been
  established with a density of at least 70.

5
Mandated Practices for Less than 1 Acre
Disturbances

• A method to prevent or reduce soil from leaving
  the site via entries or roads.
• Storm water inlet protection.
• Protection of adjoining waters.
• Drainage way protection.
• Dewatering activity sediment reduction.
• Stockpile protection.

6
5 Methods

• The Revised Universal Soil Loss Equation.
• Silt fences.
• Seed and mulch.
• Best Management Practices to achieve 40
  reduction in sediment load.
• A unique designed submitted for review.

7
More than 1 Acre Sites

• An 80 sediment load reduction is required.
• Mandated practices are the same as small sites.

8
Methods

• Same methods as small sites except silt fences
  are not recognized.

9
Stone Tracking Pad

• Either a stone tracking pad or tire washing
  station shall be used at all points of
  construction egress.
• This standard applies where construction traffic
  is likely to transport sediment off site.
• The aggregate in a tracking pad shall be placed
  in a layer at least 12 inches thick.

10
Tracking Pad

• Stone tracking pads shall be underlain with a
  WisDOT Type R geotextile fabric to prevent
  migration of underlying soil into the stone if
• Site has a high water table
• Where saturated soil conditions are expected

11
Tracking Pads

• The tracking pad shall be
• the full width of the egress point.
• a minimum 50 feet long.

12
Tracking Pads

• Surface water must be prevented from passing
  through the tracking pad. Flows shall be diverted
  away from tracking pads or conveyed under and
  around them.
• A culvert would be an approved method.
• A tracking pad plan shall include the name of the
  responsible party.

13
Tire Washing Station

• A tire washing station is another method of
  dealing with keeping soil on the site. It must
  be located on-site.
• The wash rack for a tire washing station shall
  consist of heavy grating over a lowered area.
• Rocks lodged between the tires of dual wheel
  vehicles shall be removed prior to leaving the
  construction site.
• All plans for tracking pads or washing, standard
  detail drawings, or specifications shall include
  a schedule for installation, inspection and
  maintenance

14
Maintenance

• Any sediment tracked onto a public or private
  road should be removed by street cleaning NOT
  flushing before the end of each working day.
• Tracking pads and tire washing stations shall, at
  a minimum, be inspected weekly.
• 24 hours after a precipitation event that
  produces 0.5 inches of rain or more during a
  24-hour period would create a new mandatory
  inspection of a tracking pad.

15
Maintenance

• The tracking pad performance shall be maintained
  by scraping or top-dressing with additional
  aggregate.
• If the initial thickness of a tracking pad is 12
  inches and must be maintained at 12 inches.

16

• A shallow trench or diversion dam that diverts
  surface water runoff into a dispersion area is
  called a water bar.

17
Permits

• Landowners of most construction projects where
  one or more acres of land will be disturbed must
  obtain a WPDES Construction Site Erosion Control
  and Storm Water Discharge Permit.
• If the landowner doesnt have proper permit
  coverage, they could be fined up to 10,000 per
  day.

18

• Landowners of most construction projects where
  one or more acres of land will be disturbed must
  obtain a WPDES Construction Site Erosion Control
  and Storm Water Discharge Permit.
• Landowners need to submit an application called a
  Notice of Intent (NOI) to request coverage under
  the Construction Site Storm Water Runoff General
  Permit No. WIS067831.

19
Permits

• Disturbing one acre or more of land includes
  clearing, grading, and excavating or stockpiling
  of fill material
• All construction sites disturbing 1 acre or more
  (with few exceptions) need storm water permit
  coverage!
• The landowner submits the permit application.

20

• Common pollutants in runoff include sediment,
  oil, grease, nitrogen and phosphorus
• Preventing contamination of storm water is
  critically important or polluted runoff will be
  discharged untreated - into the water bodies we
  use for swimming, fishing, and drinking water.
• Most storm sewer systems do not provide
  significant treatment to the water they collect.

21

• The erosion control and storm water management
  plans must be completed before the landowner
  files an NOI
• The landowner is required to develop a long-term
  storm water maintenance agreement that is to be
  finalized prior to submitting the NOI to the DNR.

22
Exceptions to General Applicability
ofPost-Construction Standards

• Notices of Intent prior to October 1, 2004
• Includes submittals to DNR or DSPS
• Redevelopment site with no increase in parking
  lots or roads
• Post-construction site with less than 10
  connected imperviousness ( unless parking lots
  plus rooftops gt 1 acre)
• Agricultural facilities and practices

23

• The four areas of an acceptable stormwater
  management plan includes
• Introduction and general information
• Practices (Best Management Practices)
• Normal Operating Procedures
• Maintenance

24
Silt Fences

• A silt fence is a temporary sediment barrier of
  entrenched geotextile fabric designed to
  intercept and slow the flow of runoff.
• A silt fence shall be a minimum of 14 inches
  high?

25
Building a Silt Fence

• When using wood supports, the silt fence fabric
  shall be stapled at least 0.5 inches
• Wood silt fence supports can be made from hickory
  or oak
• Steel supports for silt supports shall be a
  minimum of 20 inches extending into the ground.
• For steel support for silt fencing the fabric
  shall be attached with 50 pound plastic ties or
  wire fasteners

26

• The trench for a silt fence can be 4 inch wide by
  6 inch deep or a 6 inch deep V trench on the
  upslope side of the fence.
• The maximum height for a silt fence is 28 inches.
  
• Silt fences shall be removed once the disturbed
  area is permanently stabilized and no longer
  susceptible to erosion.

27
Sediment

• Too much sediment in a waterbody can cloud the
  water and make it difficult or impossible for
  aquatic plants to receive the sunlight they need
  to grow.