Quality of reclaimed water for turfgrass irrigation. Clinton Williams Lead Research Soil Scientist USDA-ARS ALARC

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1 Quality of reclaimed water for turfgrass irrigation Clinton Williams Lead Research Soil Scientist USDA-ARS ALARC

2 Cost for Increasing Water Supply Option Cost (acre-ft) Desalination $1,400 Recycling for Drinking Water $1,230 Imperial Valley Imports $800 Current Costs $500 Landscape Reuse $70

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4 Water Quality Problems Salinity Salts reduce water availability through osmotic effects Water Infiltration Rate Relatively high sodium or low calcium content of soil or water reduces the infiltration rate Specific Ion Toxicity Certain ions (sodium, chloride, or boron) from soil or water accumulate and cause damage Miscellaneous Excessive corrosion of equipment

5 Salinity Precipitation Temperature Precipitation (cm) < Temperature (C) > Evaporative Demand > Precipitation

6 Salt River mg L -1 imports 620,000 metric tons annually

7 Central Arizona Project mg L -1 imports 960,000 metric tons annually

8 Salt Accumulation Other 31% Groundwater 39% Salt Sinks 8% Vadose Zone 22%

9 Units for Salinity TDS Total dissolved solids (mg L -1 ) Measured by filtering then evaporating a sample and weighing the residue Common measurement at sewer treatment plants Electrical conductivity Measured by passing a current through a water sample Most management criteria based on

10 Converting between TDS and ds m = mg TDS L Conversion Factor mg TDS L = ds m (Conversion Factor) Conversion factor usually depending on solution

11 Conversion factor = 900 Conversion factor = Calculated from TDS Calculated from TDS

12 For most irrigation waters conversion factor Calculated from TDS

13 Units for ds µs mmho µmho m cm cm cm Conversion for units ds m S = µ cm = mmho cm = µmho cm 1000

14 Irrigation with Saline Water W Relative Yield, % Unsuitable for crops 20 Sensitive Moderately Sensitive Moderately Tolerant Tolerant W

15 Irrigation Water Quality Salinity Degree of Restriction on Use Units None Slight to Moderate Severe w ds/m < > 3.0 (or) TDS mg/l < > 2000

16 3.5 Chandler (ds m -1 ) /1/98 1/1/00 1/1/02 1/1/04 1/1/06 1/1/08

17 3.5 Chandler Chandler (ds m -1 ) (ds m -1 ) Jan Mar May Jul Sep Nov Jan 1 Jan/1 Mar/1 May/1 Jul/1 Sep/1 Nov/1 Jan/1 3.5 Chandler Chandler (ds m -1 ) (ds m -1 ) Jan Mar May Jul Sep Nov Jan 1 Jan Mar May Jul Sep Nov Jan

18 3.5 Chandler Chandler (ds m -1 ) (ds m -1 ) Jan Mar May Jul Sep Nov Jan 1 Jan Mar May Jul Sep Nov Jan 3.5 Chandler Chandler (ds m -1 ) (ds m -1 ) Jan Mar May Jul Sep Nov Jan 1 Jan Mar May Jul Sep Nov Jan

19 3.5 91st Avenue rd Avenue 3 3 (ds m -1 ) (ds m -1 ) Mar May Jul Sep Nov Jan Mar May 1 Mar May Jul Sep Nov Jan Mar May 3.5 Gilbert Chandler (ds m -1 ) (ds m -1 ) Jan/1/06 May/1/06 Sep/1/06 Jan/1/07 1 1/1/98 1/1/00 1/1/02 1/1/04 1/1/06 1/1/08

20 Data Collection Rate (ds m -1 ) /11/06 3/13/06 3/15/06 3/17/06 3/19/06

21 Measure salinity often meters range in price from $50 - $1000 Results are instant Track results

22 Irrigation Water Quality Sodicity Potential Infiltration Problems Degree of Restriction on Use None Slight to Moderate Severe SAR = 0-3 and W = > <0.2 = 3-6 and W = > <0.3 = 6-12 and W = > <0.5 = and W = > <1.3 = and W = > <2.9 SAR = + [ Na ] meq ; Conc [ Ca + Mg ] l 2

23 rd Avenue (ds/m -1 ) SAR Mar May Jul Sep Nov Jan Mar May

24 st Avenue (ds/m -1 ) SAR Mar May Jul Sep Nov Jan Mar May

25 3.5 Chandler (ds/m -1 ) SAR Jan/1/99 Jan/1/00 Jan/1/01 Jan/1/02 Jan/1/03 Jan/1/04

26 Irrigation Water Quality Toxicity Boron (ppm) Tolerance Class of Water Sensitive Semi-tolerant Tolerant Excellent Good Permissible Doubtful Unsuitable < to to to 1.25 > 1.25 < to to to 2.50 > 2.50 < to to to 3.75 > 3.75 Boron accumulates in leaf tips removal in clippings Problem for trees and shrubs

27 Salinity and wastewater reuse Power plant has zero discharge permit for spent cooling water.

28 Salinity and wastewater reuse Waste water is used to irrigate 250 acre farm.

29 Salinity and wastewater reuse Ongoing monitoring to determine if salt is leaching out of root zone and the effective life of the farm for waste water disposal.

30 Experimental Design Two line source sprinkler systems. One waste water One fresh water

31 Experimental Design Six irrigation levels on either side of line source.

32 Experimental Design Water level 4 is approximately equal to no leaching beyond the root zone.

33 Experimental Design Water level 5 = LF Water level 6 = LF 0.15

34 Properties of Waste Water Concentration (mg L -1 ) Ca 410 Mg 158 Na 268 K 13.2 SO Cl 276 B ds m -1

35 LF= LF= LF= = 4.3 ds m -1 0 = 4.3 ds m -1 0 = 4.3 ds m -1 LF 0 = 1.00 LF 0 = 1.00 LF 0 = ET 1 = 7.1 ds m -1 1 =6.83 ds m -1 1 = 6.5 ds m -1 LF 1 = LF 1 = 0.63 LF 1 = ET 2 = 23.2 ds m -1 2 = 19.4 ds m -1 2 = 16.3 ds m -1 LF 2 = LF 2 = LF 2 = ET 3 = 221 ds m -1 3 = 116 ds m -1 3 = 71.0 ds m -1 LF 3 = LF 3 = LF 3 = ET 4 = 33,000 ds m -1 4 = 1,541 ds m -1 4 = 472 ds m -1 LF 4 = LF 4 = LF 4 = 0.15 ARZS 6650 ds m ds m ds m -1

36 1999 Electrical Conductivity (ds m -1 ) LF LF LF Depth (ft)

37 2000 Electrical Conductivity (ds m -1 ) LF LF LF Depth (ft)

38 Results Salts in solution are not accumulating as fast as predicted. CaSO 4 precipitation. Potential B, Cl, and Na toxicity.

39 Managing Salinity and SAR Measure salinity often Monthly samples for SAR Sodium, Calcium, Magnesium Quarterly sampling for toxicity Boron, Sodium and Chloride Proper leaching fraction Replace sodium with polyvalent ions (Ca 2+ )

40 Managing Salinity and SAR Record Keeping

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