Drainage Issues in the Landscape

1
Drainage Issues in the Landscape

• Virginia Cooperative Extension
• Prince William County
• Master Gardeners
• Lorrie Andrew-Spear
• Frank Reilly

2
Shameless Commercial

• Gardening Series
• Help Line

3
Drainage Issues in the Landscape

• A. Where does the water come from and why doesnt
  it go away?
• B. Impact of drainage problems
• C. Drainage solutions

4
A. Where does the water come from and why it
doesnt go away

• Precipitation, ground water, surface water
• Watersheds
• Physiographic regions and soil types
• Soil texture and structure (particle sizes, pore
  spaces, well-drained soils vs. not, organic
  component, compaction)
• Soil horizons and water infiltration
• Run off (erosion, potential pollutants)

5
Precipitation, ground water, surface water
6
Groundwater Surface Water
7
Watersheds

• What is a watershed?
• What is your watershed?
• How can you find out?
• http//www.epa.gov/surf/
• http//www4.pwcgov.org/website/pwc-gis/

8
Prince William County Watersheds

• This county crosses 3 watersheds.
• Find environmental information for each of these
  watersheds
• 02070008 Middle Potomac-Catoctin state(s) DC,
  MD, VA, WV
• 02070010 Middle Potomac-Anacostia-Occoquan
  state(s) DC, MD, VA
• 02070011 Lower Potomac state(s) MD, VA

9
Run Off

• Flooding
• Erosion
• Potential pollutants

10
Run off affected by

• Impervious surfaces
• Slope
• Vegetation
• Previous moisture
• Infiltration rate

11
Physiographic regions and soil types

• Physiographic Regions describe land surface
  features
• Closely related to geology
• Slope, and soils are related

12
Physiographic Regions
13
Soil Structure
14
Soil Texture
15
Soil Texture

• Sand are the largest particles and they feel
  "gritty."
• Silt are medium sized, and they feel soft, silky
  or "floury."
• Clay are the smallest sized particles, and they
  feel "sticky" and they are hard to squeeze.

16
Pore Spaces

• The smaller the particles
• The smaller the pore spaces
• Water moves slowly
• Less air present

17
Pore Spaces can decrease due to compaction
18
Soil horizons and water infiltration

• Horizons have different properties
• Some may retard water flow
• Watch out for the builders horizon

19
Check for Yourself

• Dig a hole 12 inches deep and fill it with water
• 30 minutes, the soil has a drainage problem
• 24 hours, waterlogged soils may impact plant
  growth

20
B. Impact of drainage problems

• Home damage
• Puddles (mud, mosquitoes)
• Eroded topsoil, rills, gullies
• Lawns and plants (stressed drowned)

21
Home Damage
22
Puddles

• Mosquitoes
• Mud
• Further damage

23
Eroded topsoil, rills, gullies
24
Erosion Where do you think it goes?
25
Lawns and plants (stressed drowned)
26
Drainage Problems

• Damage at your home
• Damage Down Stream
• Watershed level
• Neighborhood level
• Keep the water safely on your property