Effects of NRCS Conservation Practices - National

Subsurface Drain Code: 606

Units: ft.

C F R P Pr FS D O AL

Soil Erosion Effect Rationale

Soil Erosion - Sheet and Rill Erosion 4

Soil Erosion - Wind Erosion -1

Soil Erosion - Ephemeral Gully Erosion 4

Soil Erosion - Classic Gully Erosion 1

Soil Erosion - Streambank, Shoreline, Water Conveyance C 1

Soil Quality Degradation

 Organic Matter Depletion -2

 Compaction 2

 Subsidence -2

 Concentration of Salts or Other Chemicals 2

Excess Water

 Excess Water - Seeps 4

 Excess Water - Runoff, Flooding, or Ponding 4

 Excess Water - Seasonal High Water Table 4

 Excess Water - Drifted Snow 0

Insufficient Water

 Insufficient Water - Inefficient Use of Irrigation Water 2

 Insufficient Water - Inefficient Moisture Management 1

Water Quality Degradation

 Pesticides in Surface Water 2

 Pesticides in Groundwater 2

 Nutrients in Surface water -2

 Nutrients in Groundwater 1

 Salts in Surface Water -2

 Salts in Groundwater 2

 Excess Pathogens and Chemicals from Manure, Bio-solid 0 

 Excess Pathogens and Chemicals from Manure, Bio-solid 1 

A conduit installed beneath the ground surface to collect and/or convey excess water.

Reducing water table increases oxidation of organic matter

Reducing soil profile saturation increases infiltration by improving drainage and therefore decreases water runoff. 

Improving drainage may increase surface soil drying. 

Reducing soil profile saturation increases infiltration by improving drainage and therefore decreases water runoff. 

Interception water and reduction of seeps that can cause gully formation.

Interception water and reduction of seeps that can cause streambank instability.

AL-Aso Land 

W-Water 

O-Other 

D-Developed 

FS-Farmstead 

Pr-Protected 

P-Pasture 

F-Forest 

R-Range 

C-Crop

Typical Landuse:

Control of water table - subsurface water is collected and conveyed to a proper outlet.

Not Applicable

Drains can collect water for beneficial use or reuse and improved soil, water air relationship.

Drains can collect water for beneficial use or reuse and improved soil, water air relationship.

Soils have less risk of compaction when they are dryer.

Lowering of water table allows the oxidation of organic matter.

The leached salts may be removed from the soil through drainage. 

Interception of excessive seepage through drainage.

Removal of excessive surface water through drainage will reduce flooding and ponding.

The action decreases runoff and promotes aerobic degradation of pesticide residues. Avoid direct outlet to surface water.

The action decreases deep percolation and promotes aerobic degradation of pesticide residues.

Collecting and releasing nutrient laden water removed from fields to receiving surface waters. 

The action collects and removes water and soluble nutrients from the site. 

Percolating water picks up salts that are then collected in tile lines and outletted to surface waters.

Leaching of saline and sodic soils will be intercepted before salinity reaches groundwater.

Limited decrease due to decreased runoff, but any infiltrating water with pathogens will be concentrated in tile lines

Pathogens leached from the soil will be intercepted before reaching groundwater.
 Excessive Sediment in Surface Water 2

 Elevated Water Temperature 0

 Petroleum, Heavy Metals and Other Pollutants Transporte 0

 Petroleum, Heavy Metals and Other Pollutants Transporte 1

Air Quality Impacts

 Emissions of Particulate Matter (PM) and PM Precursors 0

 Emissions of Ozone Precursors 0

 Emissions of Greenhouse Gases (GHGs) 0

 Objectionable Odors 0

Degraded Plant Condition

 Undesirable Plant Productivity and Health 2

 Inadequate Structure and Composition 0

 Excessive Plant Pest Pressure 0

 Wildfire Hazard, Excessive Biomass Accumulation 0

Fish and Wildlife - Inadequate Habitat

 Inadequate Habitat - Food 0

 Inadequate Habitat - Cover/Shelter 0

 Inadequate Habitat - Water 4

 Inadequate Habitat - Habitat Continuity (Space) 0

Livestock Production Limitation

 Inadequate Feed and Forage 4

 Inadequate Shelter 0

 Inadequate Water 0

Inefficient Energy Use

 Equipment and Facilities 0

 Farming/Ranching Practices and Field Operations 0

CPPE Practice Effects: 0 No Effect

5 Substantial Improvement -1 Slight Worsening

4 Moderate to Substantial Improvement -2 Slight to Moderate Worsening

3 Moderate Improvement -3 Moderate Worsening

2 Slight to Moderate Improvement -4 Moderate to Substantial Worsening

1 Slight Improvement -5 Substantial Worsening

Heavy metals leached from the soil will be intercepted before reaching groundwater.

Runoff and resulting erosion will be decreased

Not Applicable

The action reduces runoff and increases infiltration. Percolating water picks up metals that are then collected in tile lines.

Increase or decrease in food supply depends on plant species on the site due to soil moisture/plant relationships.

Not Applicable

Not Applicable

Not Applicable

Not Applicable

Improved drainage enhances growing environment for non-hydrophytes. If hydrophytes are desired, drainage will increase the 

problem.

Not Applicable

Not Applicable

Not Applicable

Not Applicable

Not Applicable

Not Applicable

Increase or decrease in cover/shelter depends on plant species on the site due to soil moisture/plant relationships.

The action will increase available wet habitat for some species and decrease it for others.

Not Applicable

Quantity and quality of forage species will be improved if drainage is installed to enhance their production.

Not Applicable