Taste and Odor Relationships in North Texas Reservoirs Jennifer Owens Tarrant Regional Water District
Tarrant Regional Water District Reservoir System
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) 55 694 322 649.1 315 594 345 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) 2 24 19.5 2 27.5 11 16.5 Drainage Area (mi 2 ) 143 429 * 1,7 1,97 ** 1,957 2,64 **** 839
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?
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
Historic Geosmin 23-215 Geosmin 25 2 Geosmin (ng/l) 15 1 5 1-Nov 1-Dec 1-Jan 31-Jan 3-Mar 2-Apr
Lake Benbrook Geosmin by Year
Lake Benbrook Geosmin Sources 25 Geosmin (ug/l) 2 15 1 5 CC RC BB Outlet CF BB 12/18/26 1/2/27 2/12/27
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
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.3674.1439.1568.1746 -.5.2596 Bluegreen algae cells/ml -.1746.141 -.77.985 -.1664.285 Total Algae cells/ml.136.424.755.1431 -.11.1879 Diatoms cells/ml.4581.632 -.1879.1726.5.3 Temperature C.1431 -.2339.1562.748 -.2377.3 Weekly Elevation Difference ft.283 -.479.387.479 -.283.557 Feet < Conservation Pool ft.2749.1175.11.3793.721.245 Specific Conductance umhos/cm.1 -.293.1761.226.3226.1 Turbidity NTU.943 -.2715 -.1342.4.2431.222 Weekly Pump from East TX ac-ft.566.3243 Daily Pump from East TX ac-ft.1153.2689 Weekly Watershed Inflow ac-ft -.2197 -.1565
Taste and Odor 23-29 16. 14. 12. Geosmin ng/l 1. 8. 6. 4. 2.. 2 4 6 8 1 12 Total Algae cells/ml Taste and Odor 23-29 Geosmin ng/l 1. 9. 8. 7. 6. 5. 4. 3. 2. 1.. 2 4 6 8 1 12 Bluegreen Algae cells/ml
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.
Historic Geosmin 23-215 Geosmin Median Temp 25 25 2 2 Geosmin (ng/l) 15 1 15 1 Temp (oc) 5 5 1-Nov 1-Dec 1-Jan 31-Jan 3-Mar 2-Apr
Historic Geosmin 23-215 Geosmin BB Pal Median Temp 25 25 2 2 Geosmin (ng/l) 15 1 15 1 Temp (oc) 5 5 1-Nov 1-Dec 1-Jan 31-Jan 3-Mar 2-Apr
Geosmin 25 BBPS ARPS EMPS LW CCPS RCPS PAL 2 ng/l 15 1 5 Date
Geosmin BBPS ARPS EMPS LW CCPS RCPS PAL Temp 25 2 18 2 16 ng/l 15 1 5 1-Nov 1-Dec 1-Jan 31-Jan 3-Mar 2-Apr Date 14 12 1 8 6 4 2 Temp oc
25 Geosmin Split Samples March 23, 215 CFW EEA 2 15 ng/l 1 5 ARPS BBPS CCPS EMPS PAL
Temperature and Geosmin for Lake Palestine Temp (C ) 23 19 15 11 7 3 Temperature Geosmin 2 18 16 14 12 1 8 6 4 2 Geosmin (ng/l) Date Temperature and Geosmin for Benbrook Temp (C ) 23 19 15 11 7 3 Temperature Geosmin 22 2 18 16 14 12 1 8 6 4 2 Geosmin (ng/l) Date Temperature and Geosmin for Cedar Creek 23 Temperature Geosmin 3 19 25 Temp (C ) 15 11 7 2 15 1 5 Geosmin (ng/l) 3 Date
Temp (C ) 23 19 15 11 7 3 Temperature and Geosmin for Lake Palestine Temperature Geosmin 2 18 16 14 12 1 8 6 4 2 Geosmin (ng/l) Date Temp (C ) 23 19 15 11 7 3 Temperature and Geosmin for Benbrook Temperature Geosmin 22 2 18 16 14 12 1 8 6 4 2 Geosmin (ng/l) Date Temperature and Geosmin for Cedar Creek 23 Temperature Geosmin 3 Temp (C ) 19 15 11 7 25 2 15 1 5 Geosmin (ng/l) 3 Date
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
T&O Algae Biovolume BLUEGREENS GREENS FLAGELLATES DIATOMS Geosmin 1.E+7 9 1.E+7 8 Biovolume um 3 1.E+7 8.E+6 6.E+6 7 6 5 4 4.E+6 3 2 2.E+6 1.E+ AR BB CC EMPL EM LW LP RC
T&O Algae Count Anabaena Count Geosmin (ng/l) 3, 9 8 25, 7 Count Cells/ml 2, 15, 6 5 4 1, 3 5, 2 1 AR BB CC EMPL EM LW LP RC
T&O Algae Biovolume Anabaena BioV Geosmin (ng/l) 3.E+6 9 8 2.E+6 7 Biovolume um 3 2.E+6 1.E+6 6 5 4 3 5.E+5 2 1.E+ AR BB CC EMPL EM LW LP RC
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.
Questions or Comments? Jennifer Owens Tarrant Regional Water District Fort Worth, Texas jennifer.owens@trwd.com