EFFLUENT WATER: Nightmare or Dream ComeTrue? › ?file= › 2000s › 2000 › 000315.pdf · interruptible dream-come-true water supply or a nightmare of agronomic problems depends

EFFLUENT WATER:Nightmare or Dream Come True?Effluent water is nothing to lose sleep over - you just need tounderstand the management challenges you face.by MIKE HUCK, R. N. CARROW: AND R. R. DUNCAN

JUSTTHE THOUGHT of switchingto effluent water (recycled, non-potable, wastewater, reclaimed)

causes many green chairmen, direc-tors of golf, and superintendents to losesleep. Their sweet dreams of fast greensand flawless fairways quickly turn intonightmares of deteriorating turfgrassquality. When the subject of wastewateruse is raised, stories are quickly toldabout courses losing their greens thefirst season while using effluent. Thesestories mayor may not be true, butwhen they are, there were usuallycompounding reasons for problems.Often, no adjustments were made inmanagement programs to compensatefor differences in water quality betweenthe present effluent and the formerirrigation source.

Effluent is an alternative irrigationsource that all golf course managersshould readily embrace (Borchardt,1999; Snow et a1., 1994; Zupanic,1999). While most effluent use is nowvoluntary, it is currently required insome regions. Such is the case inCalifornia, where Assembly Bill 174was adopted in 1992 mandating the useof reclaimed water (where available) forall non-potable applications such asirrigation and industrial use. Water-sensitive Tucson and Phoenix, Arizona,and Las Vegas, Nevada, also imposetheir own unique restrictions. Theyoffer incentives, limit the amount ofpotable water available, or require non-potable irrigation sources for newdevelopment projects.

Effluent water use for golf courseirrigation continues to increase acrossthe country. A survey conducted in1978 reported 26 respondents thenusing recycled water (Snow, 1979).A recent survey conducted by theNational Golf Foundation (NG F)reports approximately 13% of golfcourses nationwide now use effluentirrigation sources, and this increases to34% in the Southwest, where wateravailability is a constant issue (NGF,1999). In many areas effluent use and

associated management adjustmentswill be the norm within a few years.

In the eyes of the non-golfing public,we are wasting drinking-quality waterwhen it is used for irrigating a golfcourse with typical irrigation rates from250,000 to 1,000,000 gallons per dayfor an I8-hole golf course. The golfindustry cannot disagree with this pointand must recognize that using effluentwater is good for our image. It also isgood for the environment, as turfgrasssites can filter out and utilize nitratesand other nutrients as the water perco-lates through the thatch and soil profile,eventually to recharge groundwater.Effluent can also be good for the bot-tom line of the budget, depending onthe water quality and price whendelivered to the course. In the aridwestern states, water is a valuable re-source and annual irrigation costs canrange from $100,000 to $1,000,000 for18 holes. Considering that effluentwater is often negotiated for 80% orless of fresh (potable) water costs, thesavings frequently offset increasedmanagement costs.

Whether effluent becomes a non-interruptible dream-come-true watersupply or a nightmare of agronomicproblems depends on many factors.Ultimately, success depends on properagronomic management based on theindividual site, soil, turfgrass cultivars,and effluent quality.

Agronomic andEnvironmental Issues

Use of effluent water requires con-sideration of several agronomic andenvironmental issues (Ayers andWestcot, 1985; Bond, 1998; Snow et a1.,1994; Westcot and Ayers, 1985).

• Water Quality - The greatest dif-ference between effluent and any otherwater source such as potable, lakes,wells, streams, or rivers is the quality ofthe water. Water quality assessmentfrom a turfgrass irrigation suitabilitystandpoint (human health issues will

be discussed later) examines the waterchemistry, or more simply stated, thetypes and quantities of dissolved orsuspended constituents in the water.The quality of effluent, such as theamounts and types of dissolved saltsincluded, will vary at every locationand can change throughout the year.All effluent will have some level of saltand variable nutrient concentrations.

Many water reclamation plants offercustomers periodic laboratory test re-sults at no charge; however, these dataare often incomplete for assessingirrigation quality. Therefore, it isextremely important to have samples(soil and water) analyzed regularly byan agricultural soil and water labora-tory to develop comprehensive man-agement plans that address specificneeds of the individual site. No singlemanagement program will be appro-priate across the board for any twoeffluent users because of varying soiland water chemistry.

Water quality should be tested forthe chemical characteristics noted inTables 1 and 2. Guidelines in thesetables apply to effluent water as well asother water sources and are useful forpredicting the potential for problemsto arise with longtime use of a watersource. Also, in Tables 1 and 2 areaverage water quality values and nutri-ent contents of effluent sources inCalifornia presented as examples oftypical reclaimed water. Since effluentwater quality may vary over time,recommended maximum contractuallimits can be used to prevent the waterquality from exceeding reasonablelimits (Stowell, 1999).

• Total Salinity - The first concernwhen examining effluent water qualityis to evaluate the salinity hazard. Thiswill normally be reported as ECw (elec-trical conductivity of water) or TDS(total dissolved salts). ECw is reportedin decisiemens per meter (dSm-1) andTDS is reported in parts per million(ppm). For conversion purposes, 1.0dSm-1 ECw = 640 ppm TDS. A guide for

MARCH/APRIL 2000 15

species). c) Increases the opportunityfor direct salt toxicity to root tissues byexcess levels of Na, CI, or B. And d)enhances the potential for excessiveuptake of salts into shoot tissues whereleaf firing and tissue injury can occur.The latter two stresses are especiallyprevalent on sensitive trees/ shrubs/flowers in the landscape and on salt-sensitive grasses.

Juvenile plants are more sensitive tosalt injury than mature grasses, and ahigh salt content effluent can reduceestablishment and survival rates ofseedlings or sprigs. As an example, inregions where winter oversee ding ispracticed, increasing overseeding ratesby 10-20% may be necessary to pro-duce an acceptable quality turf whenirrigating with salt-laden effluent water,as well as applying extra irrigationwater for leaching of surface rootzonesalts prior to and after seeding.

Practical experience has shown thatestablished creeping bentgrass / Poaannua mixture greens can become dif-ficult to manage when ECw approaches1.5 to 2.0 dSm-I (soil ECe > 3.0 dSm-I),while bermudagrass greens beginshowing reduction in quality at highersalt contents, closer to the range of ECw4 to 15 (ECe 6 to 20 dSm-I). A purestand of creeping bentgrass falls some-where between these ranges, with anexception being Seaside and someother cultivars (Table 4) that have beenreported to tolerate an ECw of 6.0dSm-I while being maintained at 3/16-inch mowing height. The actual pointwhere turf decline begins is dependenton many factors such as: degree ofleaching, physical soil properties, sur-face drainage, air and soil temperatures,humidity, irrigation system efficiency,specific management programs, andthe skills of the turf manager.

Cool-season grasses are most suscep-tible to salinity stress in mid to latesummer as they become weakened byhigh temperatures, especially whenmaintained at close mowing heights.Application of sufficient leaching watervolume to prevent accumulation ofsoluble salts in the rootzone can allowgrasses to grow well up to their thresh-old ECe levels or even somewhat above,but without leaching soil EC (ECe)soon increases to above the effluentECw level and salinity stress escalates.A delay in exercising this managementstrategy can result in salinity-inducedroot and shoot dessication with a rapiddeterioration of turf quality.

• Sodium Permeability Hazard -The next great concern of effluent

2.0

4.8

164147151

-1.8

7.0220151o

1266

7.1

1.1

3.1

114130194

-2.3

194o

729

Average EmuentAsano

Stowell, et aI.,Calif.c Calif.d

>9>24>24>9

>3.0

<0.2<0.3<0.5<1.3<2.9>2.5

6-916-2416-246-9

0.7-0.21.2-0.31.9-0.52.9-1.35.0-2.9o to 2.5

In severe cases, turfgrasses can exhibitdrought stress symptoms while the soilstill appears moist. b) Causes turf-grasses to lose color and fail to respondto nutrient applications (i.e., yellowing,browning, or purpling - varies with

<6<16<16<6

<450 450-2000 >2000

Table 1Guidelines for irrigation water quality:

total salinity, Na permeability hazard, and ion toxicity problems.Also, average emuent water quality reported

by Stowell (1999) and Asano et al. (1985).

De~ree ofRestriction on Use

Slight toChemical Characteristics None Moderate SevereGeneral Water Characteristics

• pH ---------- NA ----------• Hardness (grains per gallon) 0-200 200-300 >300• Bicarbonate (HC03)(mgVI) Depends on RSC Value• Carbonate (C03)(mgVI) Depends on RSC Value

Total Salinity (Impact on Plant Growth)• ECw( dSm-I) <0.7 0.7-3.0

(electrical conductivity)• TDS (mgVI)(mgVI) a

(total dissolved salts)(total soluble salts)

Sodium Hazard (Na Permeability Hazard)• SARw or adj. SARw (meq VI)

(sodium absorption ratio)2:1 clay type1:1 clay typesand, ECw > 1.5 dSm-Isand, ECw < 1.5 dSm-I

• SARw and ECw Relationshipon Water Infiltration into SoilSARw=0-3 and ECw= >0.7SARw= 3-6 and ECw= >1.2SARw= 6-12 and ECw= >1.9SARw= 12-20 and ECw= >2.9SARw=20-40 and ECw= >5.0

• RSC (meq VI) <0(residual sodium carbonate)

Ion Toxicity (Soil Accumulation and Root Toxicity) (Sensitive Plants)b• Na (mg VI) 0-70 70-210 >210 114 164• CI (mg VI) 0-70 70-355 >355 130 147• B (mg VI) <0.7 0.7-3.0 >3.0 .44 .90

Ion Toxicity (Foliage Contact) (Sensitive Plants)b• Na (mg L-I) 0-7 >70• CI (mg VI) 0.100 >100• HC03 (mg VI) (no direct 0-90 90-500 >500

toxicity, unsightly foliage deposit)Source:Westcott and Ayers (1985) and Eaton (1950)a1 mgLl = 1 ppmbSensitivetrees and shrubs. Turgrassescan tolerate levelsabove those noted for treesand shrubs.CStowell(1999). Averageof effluentwater used on sixgolfcourses in SouthernCalifornia.dAsanoet al. (1985). Averageof water qualityfrom sixwater treatment plants(advanced treatment) in California.

evaluating the salinity hazard of anirrigation source is found in Table 1.

Buildup of total soluble salts (Na+,CI-, S04-z, K+,Ca+z, Mg+Z)in the root-zone: a) Inhibits turfgrass water uptake,thereby contributing to moisture stress.

16 USGA GREEN SECTION RECORD

Table 2Guidelines for nutrients contained in irrigation water and quantities that may be applied per foot of irrigation water.

Also, average emuent water quality'reported by Stowell (1999) and Asano et at. (1985).

Nutrient Content in Water in mg L-l (or ppm) Average EffluentConversion to lbs'l'oer 1,000 sq. ft. Asano

Nutrient or ve~ of nutrient added or every 12" of Stowell, et aI.,Element Low Normal High Hig irrigation water applIed Calif.c Calif.d

N <1.1 1.1-11.3 11.3-22.6 >22.6 11.3 ppm N = o.nIb. N per 1,000 sq. ft. 1.4N0

3- <5 5-50 50-100 >100 50 ppm N03 - = o.nIb. N per 1,000 sq. ft. 6

P <0.1 0.1-0.4 0.4-0.8 >0.8 0.4 ppm P = 0.057 lb. P20Sper 1,000 sq. ft. 8P04- <0.30 0.30-1.21 1.21-2.42 >2.42 1.21 ppm P04- = 0.057 lb. P20Sper 1,000 sq. ft. 24P20S <0.23 0.23-0.92 0.92-1.83 >1.83 0.92 ppm P20S= 0.057 lb. P20Sper 1,000 sq. ft. 18K4 <5 5-20 20-30 >30 20 ppm K = 1.5 lb. ~O per 1,000 sq. ft. 26 15~O <6 6-24 24-36 >36 24 ppm ~O = 1.5 lb. ~O per 1,000 sq. ft. 31 18Ca+2 <20 20-60 60-80 >80 60 ppm Ca = 3.75 lb. Ca per 1,000 sq. ft. 64 59Mg+2 <10 10-25 25-35 >35 25 ppm Mg = 1.56 lb. Mg per 1,000 sq. ft. 23 16S <10 10-30 30-60 >60 30 ppm S = 1.87 lb. S per 1,000 sq. ft. 65 59SO/ <30 30-90 90-180 >180 90 ppm S04- = 1.87 lb. S per 1,000 sq. ft. 196 180Mn >0.2b 0.03Fe >5.0a 0.20eu >0.2a 0.03Zn >2.0a 0.08Mo >O.OlbNi >0.2a

"These values are based on potential toxicity problems that may arise over long-term use of the irrigation water, especially forsensitive plants in the landscape - turfgrasses can often tolerate higher levels. For fertilization, higher rates than these can beapplied as foliar treatment without problems.bBased on Westcott and Ayers (1985) and Harvandi (1994).cStowell (1999). Average of effluent water used on six golf courses in Southern California.dAsano et al. (1985). Average of water quality from six water treatment plants (advanced treatment) in California.

quality is the influence of sodium onsoil structure. On fine-textured soils,Na causes structural deterioration,which reduces water infiltration/perco-lation/ drainage and often causes lowsoil O2 problems. While sand soils donot have structural aggregates to bebroken down by the dispersive actionof excess Na, any colloidal-size par-ticles (colloidal clay or organic matter)in the sand profile are more likely tomigrate downward and form a layer.In arid regions during prolonged dryperiods, routine irrigation applicationsoften cause particles to move to thedepth of irrigation water penetration insand mixes since Na keeps colloidalparticles dispersed and more prone tomigrate and eventually accumulate asa layer in the soil. Over time, this canlead to a less permeable zone andreduced water percolation, enhancethe potential for a perched water tableabove this zone, and lead to black layerformation in response to low soil aera-tion. Poor soil water permeability thatis induced by excess Na is especiallyserious if the effluent also containsappreciable salts since salt leaching isrestricted.

Irrigation water is assessed for thepotential to cause Na-induced waterpermeability problems by the use of:a) SARw-sodium adsorption ratio of

. rRECLAIMED

WATERNON

POT~BLE

water, b) adjusted SARw- the SARwadjusted for the influence of HC03

(bicarbonate) and C03 (carbonate) onprecipitation of Ca and Mg from theirrigation water and soil solution,thereby allowing Na to be dominate,and/or c) the RSC (residual sodiumcarbonate) value which uses Ca,Mg, HC03, and C03 concentrations.Carrow et al. (1999) or Carrow andDuncan (1998) have more detailedexplanations for these parameters, butbasic guidelines are presented inTable 1.

SARw is preferred for assessing theNa-induced permeability hazard whenHC03 is <120 mg L-l and CO/ is <15mg L-l. Above these levels, adj. SARwand RSC values should be used sincethese include the influence of HC03,

C03, Ca, and Mg or Na activity.A note of caution: There are cur-

rently two methods used by labora -tories to calculate adj.' SAR. The firstmethod was originally presented in the1976 edition of Ayers and WescotWater Quality for Agriculture anduses the formula Adjusted SAR = SAR(9.4 - pHc). This formula, according tothe 1985 edition of the same publica-

MARCH/APRIL 2000 17

Water is a valuable resource treated like gold in arid regions.

tion, is no longer preferred as it tendsto over-predict the sodium hazard.

The currently recommended methodof determining adjusted SAR uses theunadjusted SAR formula with a sub-stituted value for calcium derived froma table where the ratios of calcium,carbonates, and bicarbonates are com-pared to the water ECw. For more in-depth information regarding currentmethods for calculating adjusted SAR,refer to Hanson et al. (1999).

Sodium permeability hazard of efflu-ent water is affected not only by theSARw (or adj. SARw) but also bya) ECw or total salt content of the water.High ECw or total salt concentration inthe water inhibits the dispersing influ-ence of Na. Thus, SARw and ECwshould be assessed together (Table 1),and b) soil type. Expanding clays (2:1clays which exhibit cracking on dry-ing), such as montmorillonite and illite,are much more susceptible to structuralbreakdown (at adj. SARw as low as 6)than are 1:1 clays (kaolinite, FelAloxides which do not crack when dry-ing) that can tolerate adj. SAR < 16(Table 1). Particle migration by Na

18 USGA GREEN SECTION RECORD

action can occur in sands at adj. SARwof near 6 when the effluent ECw is < 1.5dSm-1• But, if the effluent containsappreciable salts (ECw > 1.5 dSm-1),migration may not occur until adj.SARw nears 16. Particle migration onsands as affected by Na is most likely tooccur during grow-in when both waterpercolation rates and water applicationrates are high.

Infiltration and permeability prob-lems can develop if the SAR or adjustedSAR is high. Gypsum, acid, or othersoil/water treatments may be appropri-ate. For a more in-depth discussion ofthis subject, please refer to a previouslypublished Green Section Record articletitled "Treating the Cause, Not theSymptoms" by Carrow et al. (1999).

• Specific Ion Problems - Severalspecific salt ions contained in effluentmay cause problems such as directtoxicities to root or shoot tissues ornutrient imbalances. These include:1. Bicarbonates and Carbonates.

High bicarbonates are relatively com-mon in reclaimed water (Table 1).While HC03- > 500 ppm can causeunsightly, but not harmful, deposits on

foliage of plants, HC03- or C03-2levelsthat result in turf nutritional problemsare not specific. Instead it is theimbalance of HC03' and C03'2 withNa+,Ca+2,and Mg+2that is most impor-tant. When HC03' + C03-2levels exceedCa+2+ Mg+2levels (in meq L-l), the Ca+2and Mg+2are precipitated as insolublelime in the soil and as scale in irrigationlines. Two problems can arise fromexcess lime precipitation (Carrow et al.,1999):• If Na+ is moderately high (> 150

ppm), removal of soluble Ca and Mgby precipitation into the relativelyinsoluble carbonate forms will leaveNa+to dominate the soil CEC sites andpotentially create a sodic (soil structuraldeterioration) condition. As noted inthe previous section, HC03 at > 120mgL-l or C03 > 15 mgL-1 in conjuctionwith at least moderate Na levels are apotential cause for concern. The degreeof Na permeability hazard can bedetermined by adj. SARw RSC valuesalong with consideration of soil typeand ECw. High Na+ on the CEC sitesalso will depress plant availability ofMg, K, and Ca. Acidification of irriga-

tion water is the normal managementoption for this situation.

• On sandy soils, the precipitatedcalcite (lime) may start to seal some ofthe macropores and reduce water infil-tration. With light, frequent irrigation,the surface may be the site of sealing.Under heavier, less frequent irrigation,a calcite layer may form deeper in theprofile at the normal depth of irrigationwater penetration. This problem is onlysomewhat serious under the combina-tion of high HCOiC03 + high Ca andMg + arid climate + sandy soil profile(Carrow et aI., 1999). The sealing canbe broken up by a combination ofcultivation (aeration) and use of acidicfertilizers or elemental S. Since it isconfined primarily to greens, acidifyingthe effluent water for a whole golfcourse would be an expensive option.In contrast, when high Na+ is presentand is a problem on all areas and soiltypes, irrigation water acidification ismore feasible and beneficial. The RSC(residual sodium carbonate) value isused to determine the potential for thisproblem where RSC = (HC03 + C03) .~

(Ca +Mg), in meq VI (Table 1).2. Toxicities from Excess Na, Cl, B.

While the guidelines for root toxicitiesor soil accumulation of these ions inTable 1 are most appropriate for sensi-tive trees and shrubs, excessive levelscan cause turfgrass root deterioration,but usually at higher levels than notedin the table. Excess Na+ can displaceCa+Z in the cell walls and cell mem-branes of root tissues and cause rootdeterioration. As excess Na+ displacesCa+Z in root cell walls and membranes,these cells often start to leak their con-tents. Potassium can be lost by rootcell leakage. Turfgrasses with low tomoderate total salinity tolerance oftenare susceptible to this type of rootinjury, which then results in roots thatare less efficient for nutrient and wateruptake. Calcium in a relatively solubleform (not lime) in the root zonecorrects this type of Na toxicity (i.e., inreality, a Ca+Z deficiency in the roottissues), especially when leaching re-moves the excess Na. Foliar applicationof Ca is not effective for Na-inducedroot toxicities since Ca is the leastmobile nutrient and is not translocatedfrom shoot to root tissues. However,grasses irrigated with effluent watercontaining high Na (>200 mg VI) butlow Ca «20 mg VI) may benefit fromfoliar Ca to limit Na replacement forCa in shoot cell wall surfaces. Thisshould be done on a limited trial basisto determine whether any visible re-

sponse occurs, since this type of shootinjury on turfgrasses has not beendocumented.

High Cl does not cause direct turf-grass root tissue injury except at veryhigh levels that are well above theguidelines in Table 1 for more sensitiveplants. Instead, Cl inhibits water up-take as a salt and, thereby, nutrientuptake. Mowing of turf normally limitsshoot injury from Cl accumulation inleaves by removal of the leaf tips.

Treatment of reclaimed water mayleave excess residual chlorine (which isClz), a highly reactive form. At greaterthan 1 mg VI residual chlorine, foliagedamage can occur. After a few hours ina holding pond, Clz dissipates into theair. Residual chlorine is normally listedas a separate item on a reclaimed waterquality test since it is not the same asCl- ions.

Boron (B) toxicities can be a prob-lem on turfgrasses, especially in aridregions. Injury is expressed as a leaf tipand margin chlorosis. Mowing of turf-grasses aids in reducing B accumu-lation in shoot tissues but at B soillevels> 6.0 mg kg-I(saturated soil pasteextract), injury may occur. Kentuckybluegrass is most sensitive at > 2.0 mgkg-I. Irrigation water containing> 3.0mg VI of B may result in soil accumu-lation. Except on acid sands, leachingof B is difficult and requires approxi-mately three times the amount of waterto leach this element than would beneeded to remove an equivalent quan-tity of Cl or total salts (Ayers andWestcott, 1985).

• Total Suspended Solids (TSS) -Suspended solids (colloidal clay ororganic particles) and dissolvedorganic matter are found in lower-quality effluent waters not receivingfiltration. Some of these organicmaterials are humic substances suchas fulvic acids and humic acids thathave been observed to show both soilaggregating and anti-aggregating quali-ties. In addition to humic substances,dissolved organic matter also may con-tain hydrophilic substances such asproteins, polysaccharides, and othercompounds (Levy et aI., 1999). Irriga-tion with low-quality effluent watershigh in organic matter load often re-sults in a significant decrease of infiltra-tion (hydraulic conductivity) by block-ing water-conducting pores. The totaleffect on hydraulic conductivity is con-trolled by the quantity of organic matterand particle sizes of the suspendedinorganic or organic solids. Unfortu-nately, no specific guidelines have

been published for predicting the TSShazard.

• Nutrient Considerations - Inaddition to the chemical characteristicsin Table 1, a number of nutrients maybe present in reclaimed water that canaffect turfgrasses and landscape plants(King et aI., 2000) (Table 2). The quan-tities of these nutrients have a majorinfluence on environmental concernsand on turfgrass fertilization programs.Important considerations with respectto the macro nutrients (N, ~ K, Ca, Mg,S) and micro nutrients (Fe, Mn, Ca, Zn,Mo, Ni, B) are found in Table 2.

Nitrogen, phosphorus, potassium,and various secondary and micronutri-ents are often contained in effluent.Like the salt content, the types andquantities of these nutrients will varydepending on the prior use of the waterand level of reclamation treatment.What is most important is to monitorand track seasonal variations throughregularly scheduled soil and wateranalyses and make adjustments in fer-tility programs accordingly. Specificnutrients are addressed in the followingsections.

1. Nitrogen. The quantity of N addedover time in the irrigation source willdirectly contribute to the nutritionalneeds of turfgrass and other landscapeplants receiving irrigation. Thus, sup-plemental N-fertilization must beadjusted accordingly and turfgrassesshould be used that can tolerate the Nlevel applied. Some turfgrasses deteri-orate rapidly when over-fertilized withN, especially those with low N require-ments such as red fescues and centi-pedegrass. On golf greens, high N in thewater may produce more growth thandesired (expressed as excess clippings,scalping, slower putting speeds, thatchaccumulation, greater succulence, andreduced hardiness), especially if thetotal annual N exceeds 4 to 6lbs. N per1,000 sq. ft. (Poa annua or creepingbentgrass) or 8 to 12lbs. N per 1,000 sq.ft. (bermudagrass). Cool-season grassesreceiving excess N during hot, drysummers are especially likely todeteriorate from over-fertilization. Ifirrigation water containing even 1.1ppm N is stored in ponds, algae andaquatic plant growth may flourish.Barley straw is an effective manage-ment option (Gaussoin, 1999) to tie upN03- in these water features and toreduce algae growth.

Effluent sources can pose a uniquesituation regarding N since a majorityof this element is taken up by plants inthe nitrate (N03-) form. Total N loading

MARCH/APRIL 2000 19

Table 3Nitrification at various soil temperatures

(adapted from Western Fertilizer Handbook, 7th edition)

Soil Time PercentTemperature (Weeks) Nitrificationa

75° F 2 100%

52° F 12 100%

47° F 12 77%

42° F 12 35%

37° F 12 5%

aNitrification: conversion of ammonia - N to N03- - N (nitrate) by nitrifying soil bacteria

in the soil is a possibility, especiallywhen irrigation applications contain-ing high amounts of organic and/orammonium nitrogen are made duringcool soil temperatures. A flush ofgrowth can result after a rapid increasein soil temperature, such as after awarm spring rain. The conversion ofammonium and organic N to nitrate isshown in Table 3 based on time andtemperature. Additionally, since Ncontent within effluent water cannot becontrolled, the possibility of developingexcessive growth and disease problemscan increase during weather conditionswhere the superintendent would nor-mally withhold fertilizer. The severityof this problem will depend on theseasonal quantity of N contained in thewater.

2. Phosphorus. The limits on P inirrigation water are lower than othermacronutrients because P is a limitingfactor for algae and aquatic plants.Excessive P that reaches ponds, lakes,or streams can markedly increasegrowth of these problem plants. Thus,turfgrasses can easily tolerate annual Padditions up to 2.0 lb. P20S per 1,000sq.ft. from irrigation water, but aquaticplants would be greatly stimulated ifthis P-Iaden water reached streams orponds. The combination of high Nplus P would also be most detrimentalin causing eutrophication (lack of dis-solved O2 in water). If steps are takento prevent lake or stream water con-tamination by P from effluent irriga-tion sources, higher P levels can betolerated. But if soil levels of P build upover time, P may reach waterwaysthrough leaching or runoff events.Buffer strips may be needed for transi-tioning into environmentally sensitiveareas.

3. Potassium. Since recreationalsites require ample K, any K in irri-

20 USGA GREEN SECTION RECORD

gation water is often viewed as bene-ficial. If K is high in reclaimed water,adequate Ca and Mg are normallyavailable to prevent any nutrient im-balances, but excess K will contributeto overall total salinity. Effluent waterhigh in total salts or Na require moreleaching of the root zone mix, whichcan easily leach K from the soil andrequire supplemental K fertilization.

4. Calcium. Potential problems fromhigh Ca were addressed in the sectionon "Bicarbonates and Carbonates."Turfgrass managers should be aware ofthe total Ca added by the water sourcesince reclaimed water and even rain-water (1 to 8 ppm Ca) contain Ca. Asnoted in Table 2, effluent water with 60ppm Ca would add 3.75 lb. Ca per1,000 sq. ft per 12 inches irrigationwater (equivalent to 16 lbs. CaC03).Thus, rainwater at 8 ppm Ca would add0.50 lb. Ca per 1,000 sq. ft. (2.2 lb.CaC03 equivalent) per 12 inches rain.Some consultants have recommendedfoliar Ca or granular Ca fertilization tomost turf sites in recent years. This is aquestionable practice unless:

• Very high soil Na+ (sodic soil) orAl+3[excessively acid (pH < 4.8)] con-ditions exist. In both cases, these ionscan replace Ca+2 from root tissues andsoil CEC sites to the point where Ca+2

deficiency in the root tissues causesroot deterioration. Even under theseconditions, shoot tissue Ca deficiencysymptoms have not been documentedon turfgrass, and soil application of Cais required - not a foliar Ca treatmentsince Ca does not translocate to theroots.

• As noted earlier, effluent with highNa (> 200 mg Vi) and low Ca « 20 mgVi) may reduce Ca in shoot tissues(this has not been determined on turf).Foliar Ca additions may be beneficialin this instance.

• Unusually high Mg additions mayrequire Ca fertilization if a Ca source isnot already required to control excessNa problems. However, the primaryresponse from adding Ca is improvedsoil physical properties since Ca is abetter soil colloid aggregating agentthan Mg. Brackish or seawater can behigh in Mg.

• Low pH « 6.0) soils benefit fromlime amendments to adjust pH towithin pH 6.0-7.5for better availabilityof nutrients in general, but Ca levels arestill adequate for turfgrass nutrientneeds even at very low pHs until thepoint of Al+3toxicity arises. Plants donot require more than 2 to 6 lbs. of Caper 1,000 sq. ft. to meet all nutritionalneeds. However, on acidic soils withpH < 5.5, a rapid greening responseafter lime or gypsum application isnot unusual. This response is due tocreating more favorable conditions forNitrosomonas and Nitrobacter stimu-lation, which transform NH4 + intoN03-. Many grasses prefer N03- andrespond to enhanced N03- availability(i.e., greening response). These soilbacteria activities are limited at low pH,primarily because of low Ca and notbecause of low pH or H+toxicity.

Problems that may occur from apply-ing Ca when not required include a)the potential to enhance Mg or K defi-ciencies (two nutrients that can bedeficient in turfgrasses), and b) causingconfusion by emphasizing a problemthat does not exist except in specialcases. Ethical and economic issuesmay arise when recommending anutrient amendment that is often addednormally by irrigation sources inabundant quantity.

5. Magnesium. Most often Mg ispresent in effluent water at lower levelsthan Ca. Sometimes, however, Mg con-tent will be relatively high, which canreduce Ca+2on CEC sites and restrict Kavailability. In these cases (and whenusing seawater or brackish water),supplemental Ca may be needed tomaintain adequate Ca for soil physicalconditions and to counter Na+ toxi-cities. Also, supplemental K will benecessary to maintain ample Knutrition.

More often than excess Mg, low Mgcontent in irrigation water or low Mgcaused by the addition of high-Caapplications using irrigation water thathas too much Na are problems. An-other problem of increasing frequencyis Mg deficiency induced by applicationof unneeded Ca on sandy sites. As withCa, knowledge about Mg content and

rates applied in the irrigation water arevery useful in avoiding deficiencies orexcessive Mg problems (Table 2).

6. Sulfur. Normally 2 or 3 lbs. 8 per1,000 sq. ft per year is sufficient forturfgrass nutritional needs, and thisamount is often provided by 804-2 con-tent in water or with N, K, or Ca fer-tilizers. It is not unusual for 804- con-tent in reclaimed water to be 100to 200ppm. Irrigation water at 200 ppm804-2 would supply 4.2 lbs. 8 per 1,000sq. ft. per 12 inches water.

The primary problem of high 80/additions onto turfgrass sites occursunder anaerobic conditions, whichtransform 804-2 into reduced 8. Re-duced 8 can react with reduced formsof Fe and Mn to create Fe8 and Mn8compounds in the soil that are con-tributors to black layer and result infurther anaerobic conditions and seal-ing of soil pores. Thus, a high 8 level is

normally not the initial cause of ananaerobic condition, but it will greatlyamplify the condition and require amore aggressive cultivation program.

When 80/ content is above desir-able levels in irrigation water, the appli-cation of lime to the soil at low ratescan "scrub" 804-2 from the system. As804-2 reacts with Ca from the lime,gypsum (Ca804) is formed. In thisform, 8 is much less soluble and isprotected from becoming reduced.Application of 10 lbs. CaC03 per 1,000sq. ft. provides about 3.8 lbs. Ca thatcan react with 9.1Ibs. 80/, which isequivalent to 3 lbs. 8 per 1,000 sq. ft.Thus, for every 3 lbs. elemental 8 (orthe equivalent rate of 9.1 lbs. 804-2)

added with irrigation water, 3.8Ibs. Cawill remove the 8 through the processof gypsum formation. The Ca can comefrom the irrigation water itself, but ifthis is not sufficient, lime can be added

to the soil surface to remove the re-maining 804-

2•

7.Iron (Fe). The 5.0 mg VI guidelinein Table 2 for Fe in irrigation water isnot related to any potential toxic levelbut to continuous use that could causea) precipitation of P and molybdenum(Mo) and contribute to deficiencyproblems for turfgrasses (P) or land-scape plants (P or Mo), b) staining onplants, sidewalks, buildings, and equip-ment, c) potential plugging of irrigationpipes by anaerobic Fe sludge deposits,which can be a problem at > 1.5 mgVI Fe, and d) high continuous rates ofFe that may induce Mn deficiency ormuch less likely Zn and Cu deficien-cies. On heavily leached sands, whereMn content is often low, this maybecome a problem. At 5.0 mg VI Fe, 12inches of irrigation water would add0.31 lb. Fe per 1,000 sq. ft., while atypical foliar application is 0.025 lb. Fe

A predominately Paa annua putting surface shows typical signs of salt-related stress such as yellowing, thinning, and more vigorousgrowth within aerification holes.

MARCHI APRIL 2000 21

Leaves of sensitive trees and ornamental species show salt stresssymptoms of scorching, discoloration, curling, and burning.

per 1,000 sq. ft. but in only 3 to 4 gal.water per 1,000 sq. ft. In most instances,Fe concentrations are low and turf-grasses will respond to foliar Fe. Whentotal salinity is high, Fe plus a cytokininas a foliar treatment is often beneficial,since salt-stressed plants exhibit lowcytokinin activity. Increased cytokininconcentration can enhance root pro-duction in salt-stressed turf plants withlow to moderate levels of salt tolerance.

In those rare cases where Fe is highenough in combination with sulfides tocause plugging of irrigation pipes andanaerobic sludge/iron bacterial slimedeposits, iron should be oxidized to aninsoluble form, precipitated and filteredbefore entering the irrigation system.Chlorinate to a residual of 1 mg/Lchlorine, or mechanically aerate in anopen pond to cause precipitation priorto filtration (Ayers and Westcott, 1985).

8. Manganese (Mn). Manganese canbecome toxic to roots of many plants.So use of water high in Mn (0.20 mgLl) can contribute to this problem,especially on poorly drained, acidicsoils. Acidic, anaerobic conditionstransform soil Mn into more soluble(i.e., toxic) forms. If effluent water ishigh in Mn, liming soil to pH 6.0 to 7.5and providing good drainage greatlyreduces the potential for Mn toxicities.At > 1.5 mg LlMn in irrigation water,Mn can contribute to sludge formationwithin irrigation lines. Also, high Mnmay inhibit Fe uptake and promote Fedeficiency. Supplemental foliar Fewould prevent this problem.

9. Copper (Cu), Zinc (Zn), Nickel(Ni). The irrigation water levels inTable 2 are based on potential todevelop toxicities on sensitive land-scape plants over time. Turfgrasses cantolerate relatively high rates due tomowing of leaf tips where these ele-me@:s tend to accumulate. Unusuallyhigh Cu and Zn could inhibit Fe or Mnuptake and thereby induce deficienciesof these nutrients, even on grasses.

10.Molybdenum (Mo). Molybdenumtoxicity would be very unlikely in turfplants, but livestock feeding on grasseshigh in Mo can be affected. Mo defi-ciency can occasionally occur on low-pH sites.

11.Other Trace Elements. Reclaimedwater may contain excessive levels ofsome elements. These are reported byWestcott and Ayers (1985) and Snow(1994). These elements would notdirectly influence turfgrass nutrition,but they would be of concern for toxi-cities on some landscape plants. Littleis known regarding heavy metals effects

22 USGA GREEN SECTION RECORD

on turf; however, because of the risk tohuman health, vegetable or herb gar-dens used by club restaurants should beprotected from receiving any effluentspray or irrigation. Local regulationsmay require a minimum setback orbuffer area irrigated by potable water inthese cases.

12. Water pH. The water pH canalter soil surface pH and thatch pHover time. Soil nutrients are most plantavailable at soil pH 6.0 to 7.5.However,the chemical constituents that causeirrigation water to exhibit a pH outsideof this range are more important thanpH by itself.

• Monitoring - Monitoring soilsalinity accumulation is recommended

to establish threshold limits to deter-mine when to leach. It is difficult torecover from salinity damage once turfbegins to decline and, therefore, leach-ing should ideally be performed beforedamage is visible. This is especiallycritical during the heat of summer withsensitive cool-season species.

Monitoring can be performed by a)collecting and submitting samples to asoil laboratory, b) visual examination ofturfgrass salt stress symptoms, or c)on-site measurements of soil electricalconductivity with a low-cost hand-held meter (Stowell, 1999). The on-sitemethod is preferred as it allows im-mediately available data to the super-intendent when determining the need

'The plant classification values and rankings are based on those traditionally used forall plants (Carrow and Duncan, 1998). The exception is the "Superior Tolerance"class, which is added to classify grasses that are true halophytes with salinitytolerances well above most plants.bOther potential cultivars include Seaside II, SR 1020, and Mariner.

2. Initiate deep root developmentprior to the onset of summer heat andsalt stress.

Spring/early summer also is the timeof the season when deep aerationtreatments would be preferred forsimilar reasons. Frequent cultivation,from mid through late summer, withless aggressive techniques like high-pressure water injection, slicing, spik-ing, star or quad-tines may also berequired. This will keep the surfacesopen to exchange gases and acceptlarge volumes of water applied to leach.If salts are allowed to accumulate in thesurface one or two inches by mid to latesummer from light, frequent irrigation,leaching before cultivation may benecessary or the water will flowthrough the cultivation holes withoutremoving salts between holes. Non-dis-ruptive cultivation also helps manageand avoid black layer development.Light topdressing after cultivation isacceptable, providing the turf is notunder heat or salt stress, but it is oftenavoided if the greens show any amountof stress. Or topdressing can be appliedat a light rate a few days before or aftercultivation during stress periods.

• Supplementary/Dual SprinklerSystems - Leaching with the stationaryin-ground pop-up systems can be per-formed provided there is good distri-bution uniformity that promotes uni-form leaching, and multiple start timescan be scheduled to avoid runoff. Per-forming a catch-can test to visuallyexamine application uniformity willshow coverage deficiencies. Performingthe leaching process over two to threeevenings also has been reported asmore successful than saturating the turfin one night. A targeted % to 1 inch ofwater is applied each night.It may be difficult to avoid exces-

sively wet surrounds and greensidebunkers when leaching with stationaryfull-circle sprinklers. This becomes amore severe problem in coastal areaswith low E.T. (evapo-transpiration)rates. Under conditions of poor distri-bution, poor internal soil drainage,and/or low E.T. rates, many superin-tendents substitute portable landscapeor orchard sprinklers with low-precipi-tation rates for leaching instead of in-ground systems (Gross, 1999). Thisallows precise placement of water onthe green surface to avoid saturatingsurrounds and bunkers. The sprinklersare simply turned on after dark andallowed to run until sunrise.

In the most severe cases of poorquality effluent, dual irrigation systems

GrassAnnual bluegrassColonial bentgrassRough bluegrassCentipedegrass

Kentucky bluegrassMost zoysia spp.

Creeping bentgrassFine-leaf fescues

BahiagrassBuffalograssBlue grama

Annual ryegrassSeaside bentgrassb

Common bermudagrassTall fescue

Zoysia matrella (some)Zoysia japonica (some)

Perennial ryegrassKikuyu

WheatgrassesHybrid bermudagrasses (some)

St. AugustinegrassSalt grass

Alkaligrass (Fults, Salty)Seashore paspalum (some)

are necessities on greens supportingsalt-sensitive, closely cut turf. Addi-tional drainage may be required on teesand throughout low-lying areas offairways, depending on the turf species'salt tolerance and internal drainagecharacteristics.

• Cultivation Programs and Leach-ing - Poor quality effluent in conjunc-tion with poor internal water drainageand/or heavily thatched turf may re-quire intensive cultivation programs tokeep salts moving downward. Aerationfrequency should be increased particu-larly in spring and early summer. Earlyseason coring of greens with hollowtines followed by backfilling withsand topdressing performs a dualfunction of:

1. Creating additional channels forwater to infiltrate when leaching duringthe summer stress period.

Tolerant (6.1-10.0)

Superior Tolerance (>20.0)

Very Tolerant (10.1 to 20.0)

Moderately Tolerant (3.1-6.0)

Moderately Sensitive (1.6-3.0)

Table 4Tolerance of turfgrasses to total salts or total salinity. Salinity values

are for soil surface conditions (ECe) where ECe is approximately equalto 1 to l.5X the effluent ECw under good leaching programs.

Salinity Tolerance Classa,ECe (dSm-1)

Very Sensitive «1.5)

to leach (Vermeulen, 1997). Inspectionports installed into drain outlets ofgreens allow collecting and samplingdrainage leachate for total salt content.

• Drainage and Leaching. Therewas once an old saying that whenbuilding a golf course one should useample amounts of both common senseand drainage. If not much of the firstwas used, then that much more of thesecond is required. This statement goesdouble when using effluent water.Ample water is needed to leach solublesalts. Positive surface drainage is thekey to avoiding puddles from formingand hence algae layer problems fromdeveloping. Even a properly con-structed USGA green will be plaguedwith these black, leather-like surfacelayers if there are "birdbaths" in thesurface that collect water. Surface,internal (soil), and subsurface drainage

MARCH/APRIL 2000 23

are installed utilizing two mainlines,one supplying potable water exclu-sively to the greens and another pro-viding effluent to the remainder of thecourse. This can greatly reduce leach-ing requirements and putting green saltstress. Finally, it is important to avoidleaching a) immediately following fer-tilizer application to avoid nutrient!nitrate leaching, and b) when heat andhumidity are ideal for disease develop-ment. The loss of turf from salt stressis slower than from disease activity;however, salt stressed turf is moresusceptible to disease damage.

• Species Tolerance - The selectionof salt-tolerant trees, shrubs, and turf(Table 4) species during constructionwill make management much easier.On an established property (retrofitproject), this matter can present prob-lems. Sensitive trees, shrubs, andflowers may require replacement. Aninter-seeding program for turf areasmay be needed to increase tolerantcultivars in the turfgrass sward. Raisingcutting heights slightly, although oftenunpopular with golfers, also can in-crease salinity tolerance of greens; theold saying "slow grass is better than fastdirt" applies when irrigating greenswith effluent water.

Salinity tolerance guidelines in Table4 are based on soil salinity (ECe).Under good leaching conditions, soilECe will usually be equal to ECw orup to 1.5x higher. But without leach-ing, surface soil ECe can increasedramatically above that of effluentwater ECw. Thus, a creeping bentgrassthat can tolerate ECe of 3 dSm-1 may dowell with effluent up to ECw = 3 dSm-1

as long as leaching prevents soil ECefrom rising above this value.

Several current projects sponsoredby the USGA Green Section researchprogram are investigating salt stressmechanisms and salt tolerance ofturfgrass species. In the future theseprojects will lead to additional cultivarsof turfgrasses tolerant of high salts andsuitable for golf. Your local GreenSection agronomist and universityextension turfgrass specialist should becontacted to provide salt-tolerant plantlists and turfgrass recommendationsadapted to your climate. Certain culti-vars within a species often performbetter than others (Table 4).

Regulatory IssuesNote: Regulations regarding effluent

water vary considerably betweenagencies. The following discussionshighlight many different regulations

24 USGA GREEN SECTION RECORD

but cannot be considered all-inclusive.It is important to contact the appropri-ate local agency monitoring effluentwater use to determine what standardsare required for each specific site.

• Cross Connection - Humanhealth concerns are the heart of effluentwater regulation no matter what agencyhas developed them. The greatest con-cern is cross connection; in otherwords, the accidental contamination ofa potable supply with effluent. Thiscould lead to an unknowing personconsuming tainted water. There are twoprimary ways that this could take place.

First would be an accidental directconnection of an effluent pipe to apotable line. To avoid this possibility,most regulatory agencies require neweffluent installations to clearly identifyany and all lines with either purplecolored pipe; burial tape marked "re-claimed, recycled, or effluent water"; orstenciling of pipe at specified distanceswith the same verbiage. The California-Nevada Section of the AWWA(American Water Works Association)first adopted purple to designate anynon-potable water sources. This hassince become the recognized standardin most regions of the country.

An annual cross connection inspec-tion of effluent-using sites is usuallyperformed by the regulating agency.This can involve a 24-hour drain-downof the clubhouse potable systems toassure they are not directly connectedto the effluent irrigation system.

A second way that effluent couldcontaminate a drinking source isthrough back-siphoning into a potableirrigation system. A simultaneous chainof events would have to take place inorder for this to occur, but nonethelessit is possible. They include:

1. A pump failure or line breakcauses a loss of pressure and drainageof the potable supply line, creating anegative pressure (vacuum) at a potableirrigation system's point of connection(POC).

2. A remote control valve for thepotable system is open, allowing efflu-ent drainage to siphon backwards intothe sprinkler head past the POC andinto the potable supply.

3. When the potable system is againpressurized, contaminated water couldthen be delivered to drinking taps.

To avoid contamination problems,anti-backflow devices, such as anRPPD (reduced pressure principledevice), double check valves, or anti-siphon valves are installed at the pointof connection between all potable

sources and irrigation systems. TheRPPD delivers the highest level ofanti-siphon protection and is normallyrequired at each potable POC at sitesusing effluent water. Biannual testing ofbackflow devices by certified personnelis usually required to maintain effluentirrigation permits.

• Line Separation - Regulationsvary considerably regarding the separa-tion distance required between potableand effluent delivery lines. Dependingon local codes, between 12 inches and10feet horizontal and a minimum of 12inches vertical separation are normallyrequired.

• Employee Training - The super-intendent is normally responsible formaintaining required records andabiding by all local regulations. Allmaintenance staff who come in contactwith or work around effluent watermust also be trained to understand thea) proper procedures used, b) rules andregulations, and c) basic cross connec-tion and backflow principles and pro-cedures applying to effluent water use.

• Inspections - Part-circle perim-eter sprinkler heads tend to fall out ofadjustment over time, and a monthlyself-inspection of perimeter sprinklersis required in some jurisdictions tomake certain effluent water is notleaving the permitted property. Thesuperintendent must submit a monthlyreport to the controlling agency.Annual or semiannual walk throughsite inspections with health departmentofficials and/or water departmentinspectors also are generally required.

• Plan Submission - Copies ofblueprints also are requested by someregulatory agencies for their files. Thisallows the agencies to have a perma-nent record of any effluent distribution/irrigation lines should public utilitiescrossing the golf course require repairs,etc.

• Public Notification - Signs, tags,and informational messages on irriga-tion equipment are often required toinform employees, golfers, and thegeneral public that effluent water isused. In most cases there is a minimumwording requirement such as: "Cau-tion - Effluent Irrigation Water, NoSwimming - Do Not Drink." Mostagencies allow additional wording thatconveys a more positive message suchas: "In the interest of water conserva-tion this facility irrigates with effluentwater. Please do not drink or swim inlakes." In addition to the minimumwording requirements, regulationsoften dictate a minimum letter size on

Creeping bentgrass is surviving within aerification holes surrounded by a white crust of accumulated salt.

such signs to assure visibility from areasonable distance.

Areas and components where post-ing/notification is often requiredinclude:

• Lakes• Control satellites• Scorecards• Property perimeters• Remote-control valves• Hose bibs• Quick-coupler valves (also mayre-

quire locking lids and/or speciallythreaded keys)

• Delivery pipe (identified by purplecolor, burial tape, or stenciled iden-tification as specified by regulatoryagency)

• Operational Guidelines - Mostagencies impose strict operationalguidelines regarding how and whenautomatic irrigation may operate.Examples include:

• Unattended automatic irrigationmay only operate between 9:00 PM and6:00AM.

• Runoff or puddling is not allowed.• Compliance failures with opera-

tional guidelines will result in thetermination of service.

• System shutdown required whenwind exceeds 15 mph.

Such restrictions can cause opera-tional problems when the need toapply water during the day arises.Touchup irrigation, watering in ofchemical or fertilizer applications, andestablishment of seed or sprigs requirean employee present to observe operat-ing sprinklers and protect unknowingindividuals from accidentally cominginto contact with effluent. This requiresadditional labor where in the past anunattended syringe cycle performed thejob. Where winter oversee ding of ber-mudagrass is practiced and multipledaytime irrigations are needed, course

closure throughout the germinationperiod becomes necessary to promotegood seedling establishment and avoidviolations.

• Miscellaneous Requirements -Other miscellaneous restrictions andmonitoring programs have been re-quired to protect adjoining properties,groundwater, etc. Examples include:

• Minimum lake lining thickness of40 mil.

• Verification of E.T. (evapotranspi-ration) versus application.

• Setbacks or a buffer zone betweeneffluent use and housing/propertylines, edible crops, potable wellheads,freshwater lakes, streams, and rivers.Distances ranging from 50 to 1,000 ft.have been reported.

• Protection of drinking water (cool-ers, fountains, etc.) on the golf coursefrom over-spray.

• Minimum daily use requirements.

MARCH/APRIL 2000 25

Posting to notify golfers of effluent water use is commonly required. Note thatat this site in California all signs must be in both English and Spanish.

• Monitoring systems to observe pH,nitrates, orthophosphate, ammonia-N,coliform bacteria, biological oxygendemand (BOD), turbidity, chlorineresidual, other changes in groundwater,freshwater streams, lakes, monitoringwells, etc. (Snow et al., 1994).

Management CostsCompliance with the various regula-

tory issues addressed in the previoussection often requires additional expen-ditures beyond that needed for use ofpotable water. Additional managementcosts or savings may also arise andthese are noted below.

• Amendment Programs - Resi-dential water softeners use rock salt(sodium chloride), while public watertreatment facilities often use soda ash(sodium carbonate) to reduce calciumand magnesium scaling problems. Bothadd sodium along with carbonates, bi-

26 USGA GREEN SECTION RECORD

carbonates, or chloride to the effluentthat cannot be removed in the reclama-tion process. Because of this, manywater districts in the Southwest that usereclaimed water for irrigation havebanned residential water softener use;however, the effort is somewhat futilewhen water softener salts can be pur-chased in local grocery stores. In somelocations, the use of KCl in place ofNaCI for water softeners is being pro-posed (Wu et al., 1995). More stringentregulations are needed along with re-search to evaluate different salts thatare less harmful to soil structure andplant growth.

The increased sodium concentrationin the water may require addingcalcium (gypsum, calcium chloride,etc.) to the soil or water. If carbonatesand/or bicarbonates are high, wateracidification could be required. Thesesituations all add costs to maintainingthe golf course and could be negotiat-

ing points when bargaining for effluentwater.

• Equipment Deterioration -Much like road salt deteriorates auto-mobile bodies in northern climates,effluent water high in salts acceleratesthe corrosion of many metals. The useof plastics, corrosion-resistant galva-nized steel, and stainless steel arerecommended along with providingpotable water at the equipment washrack area. The life expectancy of mow-ing equipment, utility vehicles, metalfencing, irrigation controller cabinets,and course accessories (metal benches,ball washers, trash cans, etc.) all willbe reduced from the daily exposure tomore saline runoff and guttation water.Maintenance and repair of equipment,especially corrosion-prone electricalsafety switches, increase.

• Retrofit Costs - Costs for retro-fitting hardware when preparing toaccept effluent may include: upgradingbackflow prevention devices, informa-tional signage, tags to properly identifyhose bibs and remote control valves,replacement of quick couplers, etc .

• Overseeding Costs - Courses thatoverseed dormant bermudagrass willbe forced to close to perform daytimeirrigation at establishment, causing aloss of revenue. Additional seed (10-20%) can be required to provideacceptable turf quality dependent onsalinity of the water.

• Water Savings - Effluent costs areoften reduced (15 percent or more thatof potable) and can offset some othercosts; however, leaching requirementsmay raise the annual quantity of waterused. This reduced cost trend may alsoreverse as demands for all water con-tinue to increase and additional usesand demand are created for effluent inthe new millennium.

• Fertilizer Savings - Some fertil-izer savings can be expected with thenutrients added by the effluent. Theactual amount will vary at each site andseasonally. It is again recommended tomonitor nutrient additions throughfrequent soil and water analysis.

• Other Costs - Often the require-ment for backflow device testing in-creases from one to two times per year.Additional laboratory testing of soiland water should be included in thebudget as well as monitoring equip-ment costs (Stowell, 1999). While efflu-ent water costs are usually 85% or lessof potable sources, agreements on long-term prices should be determined toinsure a consistent cost savings on thebasic water costs. It is the cost savings

aAdapted from Western Fertilizer Handbook - 7th Edition.bData provided by ParEx.CDataprovided by the Milwaukee Metropolitan Sewerage Company.dData provided by the Scotts Company.

46.1153.824.543.2

7.87.8

10.110.175.46.1

of the regular turnover of water. Adirect connection of the irrigationsystem to the effluent supply can elimi-nate the irrigation reservoir require-ment and problems associated withmanaging lakes; however, there thenmust be a backup system in place tosupply water in the event that thereclamation plant is shut down foremergency service. Limiting the totalnumber of lakes in a new design to onlythe irrigation reservoir will limit man-agement problems. A well-designedlake system can minimize problems.Points to consider include:

• Size lake to promote rapid turnoverof water; the fresher the water, thefewer the problems.

Table 5Salt Index (relative effect of fertilizer materials on the soil solution).

Higher salt index values indicate a greater potentialfor fertilizer burn or increasing salt load. a

Salt Partial Salt Index perIndex Unit of Plant Nutnent104.7 2.9926.9 2.44269.0 3.2534.7 0.083

52.5 4.4098.1 0.247

29.9 1.614 (N)0.8 0.0425.0 0.161

24.6 0.610.042 0.007

34.2 2.453 (N)24.5 0.647

109.4 2.189116.3 1.936114.3 1.81273.6 5.336 (N)/

1.580 (K20)0.853 (K20)2.899 (Na)0.6471.971 (K20)0.4870.390.2240.211.6180.163

MaterialAmmonium NitrateAmmonium Phosphate (11-48-0)Ammonium SulfateCalcium CarbonateCalcium NitrateCalcium SulfateDiammonium PhosphateDolomite (Calcium/Magnesium Carbonate)IBDlJbMethylene urea (40% N)dMilorganitec

Monoammonium PhosphatePolymer/Polymer Coated UreaPotassium Chloride 50%Potassium Chloride 60%Potassium Chloride 63 %Potassium Nitrate

Potassium SulfateSodium Chloride (Water Softener Salts)Sulfur Coated Urea (38% N)dSulfate of Potash - Magnesia (Sulpomag)Superphosphate 16%Superphosphate 20%Superphosphate 45 %Superphosphate 48%UreaUreaform (40% N)d

Chemical controls for algae andaquatic weeds are available but becomean ongoing expense. Another potentialproblem can arise with the continuousapplication of copper-based products.Over several years, the repeated cycle ofaquatic weed and algae blooms fol-lowed by copper-based chemical con-trol can develop an organic sludge onthe lake bottom; the sludge mayaccu-mulate a high copper content, becom-ing a hazardous waste. Straw balesare an effective biological control offilamentous algae but appear ineffec-tive in managing planktonic varieties(Gaussoin, 1999).

Irrigation reservoirs usually presentless of a management problem because

in the purchase price that will aid inoffsetting additional management!equipment costs that arise from effluentuse. Additionally, the contract shouldinclude a) definitions of the maximumacceptable water quality limits, b)delivery guarantees with access topotable water during pump or deliveryline repair periods, and c) stipulationsto avoid the required use of effluentwater when irrigation is not needed,such as in rainy periods or dormancyperiods (Stowell, 1999). It is unreason-able for a turfgrass facility to be requiredto take a certain quantity of effluentwater when it is not needed. Thistransfers excess storage and disposalrequirements from a government unitto a private user. These issues ultimatelybecome economic costs if they are notdealt with in the contract.

Other Considerations• Fertilizer Selection - Fertilizer

selection must be considered whendeveloping programs to manage salin-ity, especially where sensitive speciesare grown, and if effluent containsappreciable nutrients. Soluble, quick-release products have much higher saltindexes (bum potential) than slow-release or organic fertilizers (Table 5).Selecting products with a lower saltindex during the summer months canhelp reduce the overall salt load placedon turfgrasses and soils at a time whenET rates are high. Using a "spoon-feeding" approach of low fertilizer rateson a more frequent basis is anotherapproach. If the effluent containsample levels of a nutrient, fertilizationmay be omitted for the particularnutrient.

• ,Ornamental Lakes and IrrigationReservoirs - Effluent presents manylake management challenges as aquaticweeds and algae proliferate in nutrient-rich water. Small ornamental ponds areparticularly problematic when watertemperatures rise. They become stag-nant with strong odors developing asaquatic plants die and consume dis-solved oxygen. Little is known aboutirrigating with water low in dissolvedoxygen and its effect on the turfgrassenvironment. Some suggest that waterlow in dissolved oxygen may contributeto anaerobic problems developingsooner than normal. Aeration will re-duce odors and increase dissolvedoxygen, but can also cause foaming,thus becoming an aesthetic problem.Antifoaming agents are usually effec-tive, but they are short lived and there-fore expensive.

MARCH/APRIL 2000 27

Lake management is often more difficult witheffluent water. Various problems with algae,foaming, and aquatic weeds can develop.

28 USGA GREEN SECTION RECORD

• Line lakes to allow easy mainte-nance and cleaning following drain-down.

• Include electrical service andequipment to aerate and circulatewater.

• Provide adequate lake depths (atleast> 5 feet) to keep water tempera-ture cooler.

• Position supply inlets and pumpoutlets at opposite ends of the lake topromote circulation and avoid devel-oping stagnant areas.

• Climate - The local climate has alarge influence on management. Areasof the country that receive high rainfallmay not require regular leaching withthe irrigation system unless a droughtoccurs. Arid regions will require moreclose management and scheduledleaching events to manage sodium andsalinity accumulations.

Summary and ConclusionsEffluent water has both advantages

and disadvantages related to regulatory,agronomic, economic, and operationalissues. The greatest advantage of efflu-ent is the aspect that the supply shouldnot be interrupted by a drought. Thedisadvantages vary depending on costs,water quality, and regional/state/localoperational restrictions that may beimposed. Summary points to remem-ber include:

• Consider water quality for irriga-tion suitability (total salinity, Na perme-ability hazard, specific ion toxicities).

• Consider nutrient content effectson the fertilization program.

• Consider the climate and annualrainfall, especially the potential forprolonged extreme events.

• Provide positive surface drainage(greens, tees, fairways).

• Provide good internal drainage(greens and tees).

• Provide subsurface drainage (greens,tees, fairways).

• Regularly monitor soil and waterchemistry (in-house and with labora-tories).

• Select salt-tolerant species of turf-grasses, trees, and ornamentals.

• Adjust cultural programs as neces-sary (mowing heights/frequency, culti-vation, etc.).

• Avoid storing excess quantities ofeffluent in lakes.

• Budget appropriately.• Comply with local regulations.The thought of using effluent is most

definitely nothing to lose sleep over.Whether effluent water becomes anagronomic nightmare or not will be like

many other things in life - it's whatyou make of it! The problems aremanageable if prudent decisions aremade during construction and whendeveloping maintenance programs.Success cannot be guaranteed, butwith a well-thought-out maintenanceplan, the potential for failure shouldnot keep you awake at night, and yourdreams of having an adequate irrigationsupply during the next drought couldcome true! You can have high-qualityturf using effluent.

ReferencesAyers, R. S., and D. W Westcott, 1985.Water Quality for Agriculture. FAO Irri-gation and Drainage Paper 29, Rev. 1. Foodand Agriculture Organization of the UnitedNations, Rome, Italy.Bond, W J. 1998. Effluent irrigation - anenvironmental challenge for soil science.Aust. J. Soil Res. 36:543-555.Borchardt, J. 1999. Reclaiming a resource.Golf Course Management, Vol. 67,No.1, p.268-272, 276-278.California Assembly Bill 174 (October) 1991.Water Resources - reclaimed water -nonpotable use. In Statutes of 1991-1992Regular Session. State of California Legis-lative Counsel's Digest. Chapter 553. p.2321-2322.California Fertilizer Association. 1980.Western Fertilizer Handbook - 7thEdition. Interstate Printers & Publishers,Inc., Danville, Ill.Carrow, R. N., and R. R. Duncan. 1998.Salt-Affected Turfgrass Sites: Assessmentand Treatment. Ann Arbor Press, Chelsea,Mich.Carrow, R. N., R. R. Duncan, and M. Huck.1999. Treating the cause, not the symp-toms - irrigation water treatment for betterinfiltration. USGA Green Section Record37 (6): 11-15.Duncan, R. R., and R. N. Carrow. 2000.Seashore Paspalum: The EnvironmentalTurfgrass. Ann Arbor Press, Chelsea, Mich.Feil, K., K. Kubick, R. Waters, R. Wong.1997.Guidelines for the On-Site Retrofit ofFacilities Using Disinfected Tertiary Re-cycled Water. California-Nevada SectionAmerican Water Works Association,Ontario, Calif.Gaussoin, R. 1999. Algae control in pondswith barley bales: on-site results inNebraska. Center for Grassland Studies5 (2):3.

GCSAA. 1993. 64th International GolfCourse Conference Proceedings. GCSAAEducation Department, Lawrence, Kan.Ross, P. 1999. Flood your greens - not yourbunkers. USGA Green Section Record,Vol. 27, No.3, p. 26.Hanson, B., S. R. Grattan, and A. Fulton.1999. Agricultural Salinity and Drainage:

Div. of ANR Pub. 3375, University ofCalifornia, Davis, Calif.King, K.W, J. C. Balogh, and R.D.Harmel.2000. Feeding turf with wastewater. GolfCourse Management. 68 (1): 59-62.Levy, G. J., A. Rosenthal, J. Tarchitzky,I. Shaneberg, and Y. Chen. 1999. Soilhydraulic changes caused by irrigation withreclaimed wastewater. Journal of Environ-mental Quality. 28:1658-1664.NGF. 1999. Operating and Financial Per-formance Data of 18-Hole Golf Facilities.NGF, Jupiter, Fla.Pepper, I. L., and C. F.Mancino. 1994. Irri-gation of turf with effluent water. In M.Pessarakli (ed.) Handbook of Plant andCrop Stress. Marcel Dekker, Inc., NewYork, N.Y.Snow, J. T. 1979. Questionnaire on recycledwater. USGA Green Section Record. Vol.27, No.3, p. 13.Snow, J. T., K. S. Erusha, M. Henry, M. P.Kenna, C. H. Peacock, and J. R. Watson.1994. Wastewater Reuse for Golf CourseIrrigation. Lewis Publishers, Boca Raton,Fla.Stowell, L. 1999. Pointers on reclaimedwater contract negotiations - PacePointers (June). Web page (www.pace.ptri.-com).Vermeulen, P. H. 1997.Know when to over-irrigate. USGA Green Section Record. Vol.35, No.5, p. 16.Waddington, D.V, R. N. Carrow, and R. C.Shearman. 1992. Turfgrass - ASA Mono-graph #32. American Society of Agronomy,Madison, Wis.Westcott, D. W, and R. S. Ayers. 1985.Irrigation water quality. In Pettygrove, G. S.,and T. Asano (eds.) Irrigation With Re-claimed Municipal Wastewater - AGuidance Manual. Lewis Publishers, BocaRaton, Fla.Wu, L., J. Chen, H. Lin, P. Van Mantgem,M. A. Harivandi, and J. Harding. 1995.Effects of regenerate wastewater irrigationon growth and ion uptake of landscapeplants. J. Envir. Hort. 13 (2): 92-96.Zupancic, J. 1999. Reclaimed water: chal-lenges of irrigation use. Grounds Mainte-nance, Vol. 34, No.3, p. 33-85.

MIKE HUCK is an agronomist with theUSGA Green Section Southwest Region.Formerly a golf course superintendent, hemanaged two facilities irrigated witheffluent for more than 10 years and isregarded by his peers as a valuable sourceof information on the subject.DR. ROBERT N. CARROW (turfgrassstress physiology and soil physical andchemical stresses), and DR. RON R.DUNCAN (turfgrass genetics/breeding,stress physiology) are research scientists inthe Crop and Soil Science Department,University of Georgia, Georgia Experi-mental Station at Griffin.

MARCH/APRIL 2000 29