Compaction, disease, annual blue-grass encroachment, salt buildup,shallow roots-all these turfgrass

problems can be attributed largely to onecause, poor drainage. Turf managers spendmillions each year treating its symptomswithout digging beneath the surface to findand correct the real cause.If golf course superintendents and other

sports turf managers are expected to keephigh-use recreational turf areas in play, theymust have adequate control over soilmoisture. It is remarkable that they havebeen able to apply technology to temporar-ily overcome seasonal drainage problems.They have skillfully concealed the oversightof architects who had failed to incorporateadequate drainage into their designs, aswell as overcoming the effects of time onproperly designed drainage systems.They have also learned that drainage is a

safety net for irrigation, allowing them lee-way in estimating how much water sportsturf requires. Drainage not only guards theturf from surface-applied water, it also pro-tects it from high water tables and salt intru-sion from subsurface water.Drainage systems are more than con-

duits that remove excess water. Taken as awhole, they include the surface, the soil,gravel, numerous types of pipe, filtermaterial, moisture barriers, soil layers, andeven pumps to create suction. Each com-ponent can alter the effectiveness of adrainage system. For this reason, the turfmanager needs a basic understanding ofhow each component contributes to theoverall effectiveness of a drainage system.The drainage needs of high-use recrea-

tional turf are unique. They are considera-bly different from those for agriculturalproduction, commercial landscaping andresidential turf. Control over water in theroot zone is essential to enable turf torecover from traffic abuse and to assureplayability.The United States Golf Association was

one of the first organizations to exploredrainage systems designed specifically forsports turf. It sponsored university researchinto combinations of soil mixes and drain-pipe to improve the condition of golf greens.This led to the development of the widelyrecognized USGA Green Section method,a fairly complex procedure of completemodification of the top 18 inches of soilcombined with an arrangement ofdrainpipe.Most research in sports turf drainage has

centered around golf courses. Othermethods developed for golf courses includethe Purr-Wick and Cambridge systems.This technology has crossed over into ath-letic field construction and modification,perhaps most notably with the developmentof the Prescription Athletic Turf (PAT)systemand other methods incorporating largequantities of sand.At the same time, manufacturers of drain-

pipe have developed new products to givethe sports turf manager more options whenit comes to constructing o! modifying

30 sportsTURF

Herringbone pattern of bypass drainage installed at Saratoga Country Club in Saratoga, CA.Photo courtesy: Turf Drainage Co. of America.

DRAiNAGE: ThE SAfETyNET of SPORTS TURfMANAGEMENTdrainage systems. Among these is smallerand thinner perforated drainpipe, which canbe installed in narrow trenches to minimizesurface disturbance. They have also begunto wrap perforated pipe or plastic cores withfilter fabric to keep fine soil particles out ofdrain lines. Equipment to install new drainlines and to inject sand into existing rootzones is also more widely available.Simply installing drainpipe or replacing

soil with sand will not completely solvedrainage problems. These techniques mayhelp, but they should be considered as justpart of the solution. The sports turfmanager needs to understand thestrengths and weaknesses of every compo-nent of the drainage system. But first, hemust distinguish between the differentsources of excess water.Surface Water. The most obvious way to

control soil moisture is to restrict surfacewater. Natural rainfall, runoff from anothersite, and irrigation can be managed to vary-ing degrees.Frequently drainage problems are

caused by runoff from adjacent slopes,paved surfaces or structures. Critical turf

areas must be isolated from other areaswith interceptor drains designed to removeboth surface and subsurface water.Tarps may be impractical for golf courses,

but they play an important role for athleticfields. Tarps for football or soccer fieldsshould be large enough to - fer benchareas. Baseball qroundskseps.s can avoidrainouts by using one-piece infield tarps orindividual tarps for the pitcher's mound,catcher's box, and bases.Runoff should be a major consideration

if tarps are used. Catch basins and/orfrench drains should be located to acceptthe runoff from tarps.The slope of a turf area plays a major role

in surface drainage. A one-to-two-percentslope is generally recommended. Soils areonly able to absorb water at a certain rate.When rainfall or irrigation exceeds this rate,the excess water will flood the area unlessthe slope of the surface causes it to run off.Surface drainage also contributes to theeffectiveness of subsurface drainage.Great advances have been made in the

past few years toward applying only thecontinued on page 32

Drainagecontinued from page 30

amount of water that sports turf needs.Advanced controllers now enable turfmanagers to adjust irrigation cycles to fitweather conditions. They allow turfmanagers to repeat short cycles with adelay to prevent runoff.Sprinkler heads and pumping stations

have been refined to apply water at a ratethat the soil can absorb. Soil moisture sen-sors are being used to override irrigationschedules, and on-site weather stations canfeed data to controllers to help the managerregulate water use. These advances havetaken much of the guesswork out of irri-gation.

Subsurface Water. Controlling surfacewater is not even half the battle. One sourceof moisture to which turf managers arebeginning to pay more attention comesfrom below ... subsu rface water. Golfcourses and recreational areas are fre-quently built on flood plains, coastal landand other low-lying areas. High water tablesand subsurface water can confound effortsto control soil moisture. You will understandwhy later in the article. Poor-quality subsur-face water can also contaminate the rootzone and complicate turf management."The presence of a water table within six

feet of the surface indicates the need forimproved subsurface drainage," warns Dr.James Beard of Texas A&M University. Ahigh water table interferes with the removalof excess water from beneath the root zone,he adds.32 sporfsTURF

Small trencher often used to install bypass drainage (left).Sand groover. Photo courtesy of Cambridge Associates (below).

A network of drainpipe prevents subsur-face water from saturating the soil above-in addition to removing excess water thatpercolates down from the surface. So drain-pipe can be used to artificially lower a highwater table. As long as the water collectedby the drainpipe flows or is pumped away, anew, lower water table will be created.

Water Movement. The most difficultaspect of drainage to understand involveshow water moves into and through soils.By observation, we know that water is

pulled downward by the force of gravity. Butthere are many other forces which cancounteract gravity. For example, water willmove in a sponge or cloth from a wet areato drier areas regardless of direction. Thesame forces are at work in soils.One of the best explanations of soil-water

movement was presented by Albert Marshof the University of California at Riverside inthe book Turfgrass Science, published bythe American Society of Agronomy. Marshbrought a refreshing clarity to the compli-cated subject.Water movement depends greatly on soil

texture. That texture is determined by thesize and shape of the solid particles in thesoil and the amount of open space aroundthem. This space is commonly referred toas pore space, and may total 35 to 70 per-cent of the total soil volume.Turfgrass roots grow in these spaces by

utilizing the air, water and dissolvednutrients found in them. When a soilbecomes compacted by frequent surfacetraffic, the volume of pore space is reduced,

hampering root growth, aeration anddrainage. This is the primary justification forregular mechanical aeration of the top twoto three inches of soil, the portion of the soilmost susceptible to compaction.Clay soils consist of very small, plate-

shaped particles. While the total volume ofspace around these particles may be thesame as in other soils, the individualspaces are much smaller. Pore spaces arelarger in loam soils and largest in coarse,sandy soils.Under normal circumstances, water does

not flow through soil pore spaces like sandthrough an hourglass. Instead, water coatsthe soil particles as a film and flows fromone particle to another in film form.This film flow is slowed and even stopped

by two forces. The first is the force thathold's one water molecule to another, calledcohesion. Examples of cohesion are whena drop of water builds up at the end of aneyedropper without falling ... or thepresence of droplets on a cold glass on ahot, humid day.Soil particles hold onto water molecules

by a second force called adhesion. Theattraction between the soil particle and thewater is greatest when the film is very thin,and decreases as that film gets thicker. Asthe amount of water in the soil increases, sodoes the thickness of the film.Contact between soil particles and film

allows the forces of cohesion and adhesionto interact to move water from wetter to drierparticles. Since the contact between parti-cles is greater in fine-textured soils than incoarse soils, film flow is also greater. This isalso why fine-textured soils hold water moretightly than sandy soils.When soils of different texture are in

continued on page 34

Installing bypass drainagein green at ShenandoahCountry Club in BatonRouge, LA. Photocourtesy: Turf DrainageCo. of America.

Drainagecontinued from page 32

layers within a root zone, the contactbetween soil particles between layers is notas great. For that reason, film flow is dis-rupted. This is why a fine soil will not drainwell into a coarser soil, or vise versa. Sub-

surface layers are a major cause of poordrainage.Film flow is sometimes referred to as

capillary movement or unsaturated flow.When all pore spaces are filled with water,the soil is called saturated. This is anunhealthy situation for turf since the water

occupies the space previously available forvital gases. Beneficial microorganisms inthe soil which require oxygen can't functionproperly, and the necessary exchange ofgases between the roots and soil air is dis-rupted.At the point of saturation, the forces of

cohesion and adhesion approach zero. It isat this point that water will begin to flow bygravity through large pore spaces in thesoil. Since sand has the greatest percen-tage of large pore spaces, saturated flow isgreatest in sandy soils. Saturated flow ispoor in fine-textured soils.This is also the point at which water will

move from a fine soil into a coarser one, orfrom soil into perforated drainpipe orFrench drains.Marsh cautioned that the soil immedi-

ately above a subsurface layer or drainpipewill be wetter than the rest of the soil. Headvises that drainpipe or layers of gravel beplaced beneath the root zone of turf-grasses. Marsh said many people presumethat a gravel layer should provide excellentdrainage and are surprised when excessivewetness above the layer is revealed.For this reason slit trenches filled with

sand should extend all the way to the sur-face of the soil. If soil is placed on top of thesand, it will have to become saturatedbefore water will begin flowing into thetrench. Sand will also filter out fine soil par-

continued on page 36

BeforeFairway at Baton Rouge C.C.as it appeared in the summerof 1985. Grass could not bemaintained in area because ofconstantly saturated soil. Notethe trench that has been dugand is ready for the installationof Turf Drain.

"We move the water without the rocks. "

Turf Drain moves as much water as aFrench Drain made from pea gravel1 foot deep and 21/2 feet wide, orone made with sand that is 1 footdeep 10112 feet wide.

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AfterThis picture was taken 2 monthslater. Grass recovered and areahas firmed. This picture wastaken three days after HurricaneJuan delivered 15 inches of rain.

Turf Drainage Co. of America introduced prefabricateddrains to the golf course Industry at the 1986 GCSAAConference in San Francisco and still continues to leadthe field. For information on Turf Drain~ I circle yourreader advisory card #

34 sportsTURF Circle 201 on Postage Free Card

Drainagecontinued from page 34

ticles that can plug the openings in drain-pipe or filter fabric wrapped around them.

Percolation. The flow of water throughthe soil is known as percolation. Whendesigning a green or field, the architectshould select a soil mixture that will providea percolation rate approaching the rate of atypical rain shower. Since the uniformity ofthe soil mixture over the area is important,attention should be paid during construc-tion to make certain that all soil componentsare thoroughly mixed.Under favorable conditions turfgrass

roots will grow a foot or more deep. When

Poor infiltration isoften the result of a

heavy thatch layer inmoderate- to

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36 sportsTURF Circle 199 on Postage Free Card

poor soils and inadequate drainage shrinkthis depth to less than two inches, the turf-grass plant is stressed and is not able torecover from sports-related wear. It will alsobe more prone to drought, winterkill, dis-eases and tearing.Resodding the area will accomplish little,

since the new sod will suffer the exact samefate. New sod can further complicatedrainage if its soil texture is different fromthe root-zone mix.Part of the advantage of having subsur-

face drainpipe is lost if water is not able topercolate down to it at a reasonable rate.Soil and drainpipe must work together to beeffective.Water moves more slowly in finer soils. It

can take water in a clay-based field morethan a day to reach drainpipe installed fourfeet below the surface, explains SteveHelmrich of Advanced Drainage Systems,Columbus, OH. Superintendents andsports turf managers rarely have the luxuryof that much time. To overcome thisproblem, soils with higher percolation ratesare used and drainpipe is installed at shal-lower depths.Beard cautions that the artificial water

table created by tile should be as deep aspossible when salt intrusion is likely. Insuch cases drainpipe may need to be in-stalled as deep as six feet instead of themore common 18 inches to three feet.The shallower drainpipe are installed, the

closer they must be together, says Helm-rich. "The old rule of thumb is ten feet apartfor each foot deep." Again this dependsgreatly upon soil texture. Water movementto the drainpipe can be improved by slopingthe subgrade toward the pipe. Somedrainage systems include grading the sub-grade in a series of "hogbacks" to facilitatewater movement to the drainpipe.

Infiltration. A soil may have a reasonablepercolation rate, yet puddles still form onthe surface following rainfall or irrigation.The problem is poor infiltration. Manythings can slow infiltration. They includecompaction, an-increase in the amount oforganic matter in the surface soil, resod-ding with turf grown in soil of a different tex-ture, and development of a heavythatch/mat layer."Poor infiltration is frequently the result of

a heavy thatch/mat layer that has developedover time in moderate- to low-maintainedareas," reveals Don Hogan, an engineer ofsports surfaces in Seattle, WA. Further-more, fields or turf areas that have beenflooded will often suffer from a deposit ofsilt. For this reason, regular maintenance ofthe surface and surface soil to maintaininfiltration is critical for the protection of thedrainage system.The infiltration rate also depends upon

the texture of the soil surface. A level sandsurface will allow roughly an inch of waterper hour to infiltrate, while a level clay sur-face allows only a tenth of an inch toinfiltrate in one hour (See table for otherrates).

continued on page 38

Drainagecontinued from page 36

The slope of the surface also affectsinfiltration. Sloped portions of large,undulating greens may have a percolationrate half that of level areas. For this reason,irrigation schedules should be set to theslowest infiltration rate on the green, whichwould be the slopeo portion.Infiltration can vary within a turf area for

other reasons, complicating both drainageand irrigation. Some surface soils andthatch can actually repel water by interrupt-ing film flow. This condition is calledhydrophobia. It is detectable by noticing turfthat shows wilt symptoms before surround-ing turf, and by taking soil core samples.Wetting agents can be applied to restorefilm flow to hydrophobic soils or thatch.

Aerification, slicing and light verticuttingcan be utilized to open up hydrophobicsoils. Mixing soil cores and topdressing intothe surface following aerification will alsohelp reestablish film flow of water.Frequently, in golf course and sports turf

maintenance, natural infiltration and perco-lation are inadequate to keep turf areas safeand in play. Drainage is simply not fastenough between the surface and the drain-pipe below. In such cases, natural drainagemust be supplemented with "bypass"drainage."Water will not pass through most soils at

a rate which is satisfactory for sports turf,"states Geoffrey Davison, president of A. F.Trenchers, Sportsturf Division, in Cam-bridge, England. In cases where rebuildingturf root zones to a sufficient depth with

SOIL TYPES VS. WETTED PATTERN

Sandy Loam Clay(Coarse) (Medium) (Fine)

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SandSandy loamLoamClay loamClay

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sand/soil mixes is either too expensive ortoo disruptive, Davison recommendsbypassing the existing soil's drainage.His Cambridge system utilizes an inten-

sive, interconnected matrix of pipes and

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sand drains, combined with carefully con-trolled sand topdressing to provide animmediate exit route for surplus waterwithout its passing through the soil. Theelements of the system are customized foreach site based upon a series of calcula-tions. Specialized equipment is used toinstall the components with minimal sur-face disturbance.Pipes and/or prefrabricated drainage

structures move a greater volume of waterthan sand or gravel of the same size,explains Dennis Hurley, president of TurfDrain Inc., Marrero, LA. "Drainpipe createsair space in which water can move," saysHurley. "A 314-inch-wide vertical drainpipecreates as much air space as a 21/2-foot-wide column of gravel or a 10-foot-widecolumn of sand of the same depth. That's ahuge difference:'Turf Drain, ADS, Akzo, Lundin and War-

ren's are among manufacturers of vertical-bypass drainage structures. Theseproducts can be installed quickly withsmall, economical trenchers with little sur-face disturbance. "Obviously, they must beinstalled deep enough below the surface tobe out of reach of aerifiers," explainsHurley. "Then fill the trench to the surfacewith sand, not gravel." Sand prevents siltand fine soil particles from clogging thegeotextile wrapper of the drains.Water does not enter the top of bypass

drainpipe initially. First it moves downward,

at the rate allowed by the sand, to the bot-tom of the trench where the backfill starts tobecome saturated. As the level of saturationrises to the bottom of the pipe, water beginsto enter the lower slots. Water will not enterthe top slots until the pipe nears capacity.The spacing of bypass drainage should

be determined carefully. Too muchdrainage can be as much a problem as toolittle-and the use of bypass drainagewithout irrigation is not advised.First determine how much water needs to

be removed, and how quickly. A golf courseor sports field located in a region wherestorms can dump up to two inches of rainper hour should have closer spacing than inan area where one inch of rain per hour istypical. If a facility can afford two hours fora field to drain, the spacing can be largerthan where immediate removal isnecessary.The spacing on sloped sites should be

closer than on flat sites. Since heavy, fine-textured soils hold onto water longer, spac-ing for these should also be closer.Manufacturers and their distributors can

tell you how much water a particular drainstructure transports in gallons per minute.They can also help you calculate how manygallons of water fall over an area per minuteto match drainage with rainfall. Warren'sSpecialty Products has developed a com-puter program to determine spacing basedupon all these factors.

In general, spacing will range from eightto 15 feet for greens and 15 to 60 feet forfairways and athletic fields, says Hurley. "Itdepends largely on site conditions:'Bypass drainage is proving to be a prac-

tical way to renovate older, poorly designedsystems without major reconstruction.Better drainage and irrigation give the

manager the control he needs to increasethe durability and condition of naturalsports turf. Superintendents can speed upgreens for tournaments and sports turfmanagers can reduce compaction andimprove durability of fields by reducing soilmoisture before events.They can lower surface moisture to dis-

courage encroachment of annual bluegrassor the development of diseases. They canalso increase soil moisture temporarilywhen aerifying, overseeding, or applyingfertilizers, insecticides and soil herbicides.The control provided by drainage reachesnearly every phase of turf maintenance.That is why drainage is said to be the

most important aspect of sports turf design,construction and maintenance. Gooddrainage is an inescapable precondition ofhigh-use recreational turf. Without it, thesports turf manager is trying to balance ona tightrope-without a safety net to catchhim in case he falls. It's too risky.The bottom line is, according to Hogan,

"If you can't afford proper drainage, you'regoing to waste money on everything else:'

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February, 1989 39