f1 drainage fundamentals
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Drainage Fundamentals
1
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Module A: Fundamentals
Pores space
Infiltration and Saturation & Field capacity
Gravity & Capillary action & Surface tension
Lateral movement, rising table and free water
2
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Soil Structure And Pore Space
Water content decreases due
to rate of drainage by
gravity
Remaining water held in narrow pores
Water is prevented from
moving: hydraulic
conductivity
HC is particle size transfer
3
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Drainage occurs when:
Pore spaces are filled
Gravity exceeds
surface tension
Gravity pulls water
downward
4
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Pore spaces
Soil particles fit imperfectly
Inter packing: sand/clays
Little room for air/water between particles
5
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Factors affecting Water intake and retention
Infiltration
Saturation
Field capacity
Hydraulic conductivityAdhesion and surface tension
6
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Infiltration rate
Irrigation should occur between stress point and
field capacity
Soil accepts water highest in this range Infiltration rate is variable
*if rain is falling faster than gravity can pull it down the profile, the surface will saturate
Runoff will occur
7
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Saturation
Saturation may occur at varying depths
Changes in soil profile affect saturation
Consistent soil profile is key to progressive water movement into
profile
8
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Field Capacity
Defn: moisture status of the soil, where gravity cannot pull more water from a
saturated profile.
Air space also critical for root growth.
Pore space allow roots to force their way through soil
% pore space = % root growth
9
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Water Adhesion to Soil particles
Coarse sand pores are large
Silt/clay pores are small
The finer the pores, the tighter the adhesion between particles
10
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Wilting point
Plants ceasing to extract water is called
“wilting point”
Only remaining water is held too tightly by
adhesion for plant use
11
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Surface Tension
Click icon to add clip art
The smaller the drop, the stronger
the tension
Dusts and insects on the water
surface shows tension
12
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Gravity
As depth increases, so
does the weight of water
All but capillary water is affected
by gravity
13
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Capillary Fringe
A saturated zone at the bottom of topsoil, above a
slow draining baseOften a winter problem
*if a hole is dug into the capillary fringe zone, no water will enter this hole even if the surrounding
soil is saturated
14
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Capillary Fringe
A saturated zone where no
lateral movement (to
drains) will occur
If a hole is dug into the capillary zone, it will NOT
fill with water
If a hole is dug below the
capillary fringe, it will fill with
water.(“head”)
Where head is greater than
surface tension, of menisci pores
it will drain
15
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Capillary action
Stronger than gravity
Water molecules are attracted to the
adhesive forces of surface molecules
Laterally pulled or vertically
16
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
17
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Capillary Action
If capillary sizes are the same
along the menisci, gravity will prevail
Water only moves as a result of
capillary forces until the soil reaches field
capacity.
Capillary water never moves through large
pores
18
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Lateral movement of water in soils
Lateral movement occurs slowly
Rarely moves more than 4” from source
Depends highly on pore space of soil
Capillary distances/movement is greater in silty clay vs sand (small vs large
pore space)
19
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
20
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Rising water table
Likely found in the middle of a
slope
Water at bottom of slope is
surface water problem
Flows along seams in gravel
profile
If shallow capped (with clay) it will
break the surface
21
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
To alleviate rising water table (springs)
Locate the water source (piezometer)
Intercept at gravel layer
uphill
Install drainage to off-site
Result will avoid digging on
site/wet area
22
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Piezometer
23
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Natural Deep drainage
Non capillary pore spaces
Natural drainage through the subsoil
Into drain pipes installed (large
piping installed at construction stage)
Hydraulic conductivity greater
than.04mm/hr required in subsoil
Construction on dry soil is important for subsoil compaction
of pore space
24
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Free Water vs capillary fringe
25
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Drainage Fundamentals
Perched water table
Capillary Fringe and free water zones
Hydraulic conductivity
Drain Spacing: Hooghouts Formula
26
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Perched Water table
Fine textured material over a
coarse one
no water drains from a finer
material until capilary fringe is built above the
coarser material
If height of capillary fringe exceeds
topsoil, it will never drain
27
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
How does a perched water table work?
28
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Height of Perched table
Determined by pore size distribution
Fine textured soil has deep saturated zone,
coarse is shallow29
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Perched Heights
USGA sand = 5-9” perched table 1.5mm coarse
sand = 2” perched
4mm gravel = .75” perched
tableSurface tension (menisci) reaches equilibrium with
gravity and drainage stops
30
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Perched Water Table
31
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Perched water table
The saturated zone from bottom of profile to air entry point is called capillary fringe
Zero suction at base, no free water present
32
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Capillary fringe: Air entry point
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000 33
The pull of gravity breaks surface tension of large pores,
which drains down profile
Field capacity is reached when no more water can be pulled from the profile-adhesion and
surface tension are equal
Capillary Fringe:
Click icon to add clip art
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000 34
The only water that can move into subsoil
drains is from the free water zone
Capillary fringe
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000 35
All movement of water ceases
when free water zone is drained
Continued drainage is
determined by rate of base
Movement into secondary profile
36
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Saturated Free water zone
37
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Saturated Free water zone
38
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Hydraulic conductivity: USGA spec( SHC)
Rate is affected by pore size
Water moves 100X faster
through a USGA sand root zone
than loam
When saturated, GRAVITY pulls
water downward faster
Field capacity is reaching
equilibrium of surface tension
and gravity
39
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Hydraulic conductivity: testing
Conductivity varies greatly by the amount of fines in the soil (silt)
Unusual for a soil to have greater than
2”/hr hydraulic conductivity
This conductivity requires a functioning perched water table
to grow turf
40
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Hydraulic Conductivity: Soil Types
• Surface grading and drainage critical
Silt/Clay Loam 20-45% fines particles<.1mm = .2-.4”/hr (5-10mm) *common on fairways
Sandy Loam >20%fines particles <.1mm = .4-2.0”/hr (10-50mm)
41
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Hydraulic conductivity:
Any sports turf field has to be drained to field capacity to allow play - top 2” of soil
Therefore: Free water zone must be drained down to field capacity
quickly
42
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Tube experiment: Moisture release curve
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000 43
Hooghouts: Defined terms
D:
= drainage rate (“/hr) of saturated free water zone at midpoint
44
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Hooghouts Formula:
K:Saturated hydraulic conductivity of top soil in inches/hr
45
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Hooghouts Formula
H² is equivalent to Ha X Hb
Ha = height of saturated free water zone,Hb = height of saturated free water zone that water must flow through
46
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Hooghouts Formula
S² is equivalent to Sa X Sb
Sa = is the distance between drainsSb =distance between drains where component of the area water is collected
47
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Hooghouts formula: Calculating rate of drainage at midpoint
Calculations to reduce height of free water BETWEEN drains
48
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Hydraulic conductivity
A description of various soils and conductivities
49
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Silt/Clay Loam
20-45% fines( particles less
than .1mm)
Common on fairways and sportsfields
Hydraulic conductivity:• .2-.4in/hr, 5-10 mm/hr
50
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Sandy Loam
Less than 20% fines (particles less than .1mm)
Contain fines, but sandier
Drain faster, but compact to low conductivity
Hydraulic conductivity:• .4-2in./hr, 10-50mm/hr
51
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Hydraulic Conductivity .2”/hr(no surface drainage)
52
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Slow draining base(no surface drainage)
53
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Hydraulic conductivity .8”/hr(no surface drainage)
54
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Hydraulic conductivity 2”/hr(no surface drainage)
55
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Summary: What does this tell us?
Water moves laterally very slowly
Traditional thinking of drainage is suspect
Drainage of base, is more important than
installing subsoil drains.
Explains why vibra-molling works so well•Opens up the base and makes it drain better
Subsoil must be sufficiently dry to
fracture – compaction while wet will make the surface impermeable.
56
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Summary
Effective drains need to be spaced close together, 3.3ft in
most soils
The base will remove water quicker than drains spaced
further apart
High organic soil content has high hydraulic conductivity
57
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Summary: Problem solving HC
Measure your soil
depth
Identify it’s hydraulic
conductivity
Test your drainage
base in a lab for
conductivity rate
Calculate drainage spacing using
Hooghouts
Determine if subsoil
drainage is really worth
it!
58
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
59
Designing subsoil drains
60
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Discharge area: Subsoil drains
Decide where to discharge the waterDesign UP from discharge point (minimum 1:70)Have uniform fall on all pipes
61
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Discharge area: Subsoil drains
Open drainCreekBe aware what will happen during floodingDischarge must be above levelDesign the drain FROM the discharge point upwardUniform fall on all pipes
62
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Subsoil drain pattern:
Favoured design30-45% angleSmall laterals into larger mainFlexible corrugated tileJoints are offset from each other
63
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Determining pipe sizing
Manufacturers supply max flow performanceAs pipe length increases, friction loss increasesMain runs with the slopeLaterals run across slope
64
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
A fall of .5ft in 49.5 ft is 1:99
Efficient and simpleLaterals same distance apartUniform drainage for the whole area
65
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Calculating pipe required
66
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
How to size pipe
Assume area of 1ac (43,560ft sq)Uniform slope of 1:70, down 295 ft. no cross fallSubsoil drains spaced at 6.6ft, topsoil at 12” HC 2”/hrRainfall event of 2”/hr
67
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Example of racetrack drainage
68
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Sizing drains
High traffic area with subtle drain coverOff back of greenRealistic sizingNo additional labor for trimming/maintenance
69
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Principles of Subsoil Drainage
MigrationFilter material
Installation techniques
70
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Choosing the right filter material
Filter material should bemade on the basis of type or sand that will surround itIf the drain is in a fine soil, filter should be a coarse river sand-NOT GRAVEL!
71
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Migration of particles
Significant amount of fines enter the surrounding soilTHIS moves fines into the pipeQuickly collapses the drain, often during first few waterings
72
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
73
Particle migration into coarser gravels
Common mistakes:Surround pipe with coarse gravel or crushPea gravel ¼ - 3/8” often specifiedOverall, these gravels are too large!!
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
74
Filter material entering pipeWe are too worried about filter material entering the drain pipeIf gravel is used, smaller particles will migrate into the large pores
When to use gravel filter material
Only in USGA spec greens
D15 of the gravel must not exceed the D85 of the
sand zone
This is the “Bridging Factor”
75
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Clean filter material
Make sure no fines in the filter materialUse HC of the filter material >100”/hr (sand withought fines)Misconception: Sand will not enter drain pipe except from above. Surface area of slots is less that 1% of pipe surface area.
76
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Bridging factor
If gravel is too coarse, bridging factor will be too highUsing finer filter material prevents migration of particles from surrounding soil.
77
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Diameter rating
When installing subsoil drains, in any situation other than USGA sand, use clean washed sand. NOT pea gravel, or any gravel with a D15 less than 1mm. D15 means 15% of the filler is larger than the specified size, 85% spec.
78
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Installing subsoil drains
Cut into the area below the soil to be drainedMake sure sides are verticalAvoid subsoil contaminationProvide uniform slope
79
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Installing subsoil drains1. Clean vertical trenches2. 2” of sand at bottom of trench3. Even slope4. Correct high/low points 5. Lay slits on BOTTOM of trench
*water enters pipe from the bottom
80
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Installing subsoil drains
5. Cover the pipe with filter sand 2” surrounding
6. Firm down/light rolling7. Use commercial joints
81
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Geofabrics: Never wrap pipes
Fabric on drains are unnecessary
If correct sand has been used, fines will effectively pass through the drainage system
Geo textile drastically reduces drainage rates
82
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Types of pipes
Flexible slotted (agricultural)
2-8” diameterCommonly used is 4” outer diameterSlot size varyThese pipes self-clean, depositing fines though the ridgesThis process will not block pipes
83
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Types of drain pipes
PVC solid drain pipe – Improved
flow for collectors
Multi flow – slit drainage
Atlantis draincell http://www.atlantiscorp.com.au/video
84
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
Common drainage mistakes
Incorrect backfill materialIncorrect pipe connectorsMisunderstanding of surface and subsurface drainage
85
Practical Drainage for Sportsturf, Golf, and Horticulture. Keith
McIntyre, Brent Jakobsen, Ann Arbor Press, 2000
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