Taste and Odor Relationships in North Texas Reservoirs. Jennifer Owens Tarrant Regional Water District

Transcription

1 Taste and Odor Relationships in North Texas Reservoirs Jennifer Owens Tarrant Regional Water District

2 Tarrant Regional Water District Reservoir System

3 Reservoir Facts Lake Arlington Benbrook Lake Cedar Creek Lake Eagle Mountain Lake Richland - Chambers Lake Lake Worth Lake Palestine Year Constructed 3/31/1957 9/29/1952 7/2/1965 2/24/1934 7/17/1987 6/1/1914 6/13/1962 Conservation Pool (ft) Conservation Volume (acre-feet) 38,8 88,25 637,2 178,4 1,137, 37,7 373,22 Surface Area (acres) 1,939 3,635 32,623 8,738 41,356 3,458 22,656 Mean Depth (ft) Drainage Area (mi 2 ) * 1,7 1,97 ** 1,957 2,64 **** 839

4 Study Objectives Alert for water treatment plants! When does the Geosmin peak? Which reservoirs have the highest Geosmin? Why do some reservoirs have high Geosmin? Is there a way to predict high Geosmin?

5 Sampling Protocol 7 Reservoir Intakes weekly from Nov-Mar Started in November 23 (Pal added in 211). 11 years of data. Geosmin, MIB run by CFW Water Lab Field data: Temp, DO, ph, SpC, Turb Lab Data: Algae Enumeration Hydrology: Res Elevation, Pipeline Inflow, Tributary Inflow

6 Historic Geosmin Geosmin 25 2 Geosmin (ng/l) Nov 1-Dec 1-Jan 31-Jan 3-Mar 2-Apr

7 Lake Benbrook Geosmin by Year

8 Lake Benbrook Geosmin Sources 25 Geosmin (ug/l) CC RC BB Outlet CF BB 12/18/26 1/2/27 2/12/27

9 Geosmin Correlations Overall Medians for 6 years on 6 reservoirs (n = 6) red = p<.5 Variable Units r Chl'a' ug/l.71 Bluegreen algae cells/ml.88 Total Algae cells/ml.77 Diatoms cells/ml.47 Temperature C -.6 Weekly Elevation Difference ft -.85 Feet < Conservation Pool ft.2 Specific Conductance umhos/cm -.9 Turbidity NTU.38 Variation in Elevation Stdev.82

10 Overall Correlations for each reservoir with 6 years of data n ~ 85, Red p<.1, Green p<.5 Variable Units AR BB CC EM LW RC Chl'a' ug/l Bluegreen algae cells/ml Total Algae cells/ml Diatoms cells/ml Temperature C Weekly Elevation Difference ft Feet < Conservation Pool ft Specific Conductance umhos/cm Turbidity NTU Weekly Pump from East TX ac-ft Daily Pump from East TX ac-ft Weekly Watershed Inflow ac-ft

11 Taste and Odor Geosmin ng/l Total Algae cells/ml Taste and Odor Geosmin ng/l Bluegreen Algae cells/ml

12 Conclusions Peak Geosmin when reservoir temp ~ 1 o C BB, AR highest, Median 8 ng/l. RC distant 3 rd at 3 ng/l Winter Taste and odor problems are not simply a matter of how much algae or how eutrophic a reservoir is. Correlation analysis does not suggest Causeeffect analysis at this point.

13 Historic Geosmin Geosmin Median Temp Geosmin (ng/l) Temp (oc) Nov 1-Dec 1-Jan 31-Jan 3-Mar 2-Apr

14 Historic Geosmin Geosmin BB Pal Median Temp Geosmin (ng/l) Temp (oc) Nov 1-Dec 1-Jan 31-Jan 3-Mar 2-Apr

15 Geosmin 25 BBPS ARPS EMPS LW CCPS RCPS PAL 2 ng/l Date

16 Geosmin BBPS ARPS EMPS LW CCPS RCPS PAL Temp ng/l Nov 1-Dec 1-Jan 31-Jan 3-Mar 2-Apr Date Temp oc

17 25 Geosmin Split Samples March 23, 215 CFW EEA 2 15 ng/l 1 5 ARPS BBPS CCPS EMPS PAL

18 Temperature and Geosmin for Lake Palestine Temp (C ) Temperature Geosmin Geosmin (ng/l) Date Temperature and Geosmin for Benbrook Temp (C ) Temperature Geosmin Geosmin (ng/l) Date Temperature and Geosmin for Cedar Creek 23 Temperature Geosmin Temp (C ) Geosmin (ng/l) 3 Date

19 Temp (C ) Temperature and Geosmin for Lake Palestine Temperature Geosmin Geosmin (ng/l) Date Temp (C ) Temperature and Geosmin for Benbrook Temperature Geosmin Geosmin (ng/l) Date Temperature and Geosmin for Cedar Creek 23 Temperature Geosmin 3 Temp (C ) Geosmin (ng/l) 3 Date

20 18, T&O Algae Count BLUEGREENS GREENS FLAGELLATES DIATOMS geosmin 9 16, 8 14, 7 12, 6 Number Cells/ml 1, 8, 5 4 6, 3 4, 2 2, 1 - Nov Dec Jan Feb AR BB CC EMPL EM LW LP RC

21 T&O Algae Biovolume BLUEGREENS GREENS FLAGELLATES DIATOMS Geosmin 1.E E+7 8 Biovolume um 3 1.E+7 8.E+6 6.E E E+6 1.E+ AR BB CC EMPL EM LW LP RC

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23 T&O Algae Count Anabaena Count Geosmin (ng/l) 3, , 7 Count Cells/ml 2, 15, , 3 5, 2 1 AR BB CC EMPL EM LW LP RC

24 T&O Algae Biovolume Anabaena BioV Geosmin (ng/l) 3.E E+6 7 Biovolume um 3 2.E+6 1.E E E+ AR BB CC EMPL EM LW LP RC

25 Conclusions Cool water temperature continues to be consistent indicator of geosmin episode in reservoirs with history of geosmin. Significant presence of Anabaena is promising although consistency is still being evaluated. Lag time and severity of geosmin episode will continue to be explored. Continue to evaluate other potential algal or bacterial sources of geosmin to reservoirs.

26 Questions or Comments? Jennifer Owens Tarrant Regional Water District Fort Worth, Texas