Phosphorus Loading and Related Impacts in Southern Cayuga Lake. Dave Matthews Upstate Freshwater Institute Syracuse, NY

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1 Phosphorus Loading and Related Impacts in Southern Cayuga Lake Dave Matthews Upstate Freshwater Institute Syracuse, NY

Upstate Freshwater Institute (UFI) mission: advance freshwater research and protect the freshwater resources of New York State established in 1981 not-for-profit [51(c)(3)] independent, with close

2 Upstate Freshwater Institute (UFI) mission: advance freshwater research and protect the freshwater resources of New York State established in 1981 not-for-profit [51(c)(3)] independent, with close professional ties to SU and CESF interdisciplinary research 27+ peer-reviewed manuscripts Systems studied: Onondaga Lake, Three Rivers System, Finger Lakes, NYC Reservoirs, Great Lakes, Lake Champlain

3 Symptoms of Excessive P Loading high levels of phytoplankton biomass blooms of nuisance cyanobacteria low transparency Common Metrics of Trophic State total P concentration - TP chlorophyll concentration - Chl Secchi disc transparency SD

4 Contributing Data Sets Cornell University-Lake Source Cooling (LSC) bi-weekly, April-October, 9 sites in southern Cayuga Lake, phosphorus, chlorophyll, Secchi disc Upstate Freshwater Institute phosphorus measurements in Cayuga Inlet and Fall Creek synoptic surveys of the Finger Lakes in 1996, 24 Community Science Institute Fall Creek phosphorus measurements during high flows Ithaca Area and Cayuga Heights WWTP phosphorus loading information

5 Cayuga Lake: LSC Monitoring Sites LSC Discharge ~8 km (8) m south shelf Wind (5) (6) main lake N N LSC Intake Taughannock Point (8) LSC Intake km 7 m approximate depth contours 4 m 6 m 4 m Site Key 8 - main lake reference LSC - intake location 1,3,4,5,7 - south shelf 2 - Ithaca WWTP plume (6) (5) (1) (3) pile cluster (4) (2) Ithaca Area WWTP km 1 LSC discharge (7) Cayuga Heights WWTP T921 Fall Creek Cayuga Inlet

6 Partitioning Flows and Phosphorus Loads to Southern Cayuga Lake Q (m 3 /s) (a) TDP L (kg/d) PP L (kg/d) (b) (c) Fall Creek Cayuga Inlet IAWWTP CHWWTP LSC tributary inputs dominant during high runoff years (24, 26) 5% reduction in Ithaca Area WWTP load beginning in 26

7 Long-term Variations in Chl, TP, and Secchi Disc Transparency Chl (µg/l) TP (µg/l) SD (m) (a) (b) (c) pelagic, this study shelf, this study pelagic, other shelf, other Chl levels similar on the shelf and in the main lake TP levels higher on the shelf than in the main lake clarity lower on the shelf than in the main lake disconnect between Chl and Year TP/clarity caused by inorganic particles

8 Evaluation of the Relationship Between TDP Loading and Chlorophyll Levels annual average values for years ( ) Chl (µg/l) TDP L (kg/d) r ²=.67 strong relationship between TDP loading and phytoplankton biomass however, the shallow slope indicates little bang for the buck

9 Impacts of Runoff Events on Southern Cayuga Lake, 24 TDP (µg/l) PP (µg/l) Q (m 3 /s) (a) (b) (c) shelf pelagic fixed-frequency sampling program captured one major runoff event major increases in PP and turbidity on the shelf during early September storm the main lake was unaffected Tn (NTU) (d) Jun Jul Aug Sep Oct 24

10 Turbid Plumes Entering Cayuga Lake Cayuga Inlet and Fall Creek Taughannock Creek Photos by Bill Hecht

11 Flushing Rate of the Southern Shelf of Cayuga Lake Flushing Rate (d -1 ) (a) plug flow mass balance analysis JUN JUL AUG SEP OCT 21 the southern shelf of Cayuga Lake flushes rapidly, about once per day during the summer months this is mostly due to exchange with the main lake explains modest water quality differences between the shelf and main lake

12 Selected Limnological Features, Cayuga Lake and other Finger Lakes x denotes location of sampling site

13 Finger Lakes Wide Studies: Cayuga Lake Rankings, Secchi Secchi Depth Conesus Hemlock Canadice Honeoye Canandaigua Keuka Seneca th Cayuga Owasco Skaneateles Otisco Disc monthly monitoring Secchi Depth Conesus Hemlock Canadice Honeoye Canandaigua Keuka Seneca 24 6 th Cayuga Owasco Skaneateles Otisco

14 Regulation of Secchi Disc: Finger Lakes Peng and Effler 25

15 Summary phosphorus loading to southern Cayuga Lake is dominated by tributary inputs, particularly during high runoff years modest water quality benefits expected from a 5% decrease in phosphorus loading from Ithaca Area WWTP clarity on the southern shelf is regulated by terrigenous inorganic particles rather than phytoplankton the southern shelf flushes rapidly (once per day), which moderates water quality differences with the main lake differences in transparency among the Finger Lakes explained by concentrations of inorganic particles and phytoplankton

16 This study was funded by a FL-LOWPA Special Projects grant Project partners: Tompkins County City of Ithaca Cayuga Lake Watershed Network Questions?

17 Phosphorus Cycling in Lakes external loading (dissolved, particulate) bioavailable P primary production deposition export sediment diagenesis internal loading total phosphorus (TP) = total dissolved P (TDP) + particulate P (PP)

Longitudinal and Vertical Patterns - August 1996, 4 sites Depth (m) 5 15 2 25 3 5 15 2 3 LSC 8 (a) T T ( C) c(66) (m -1 ) [Chl] f (µg/l) 5. 7.5. 12.5 15. 17.

18 Longitudinal and Vertical Patterns - August 1996, 4 sites Depth (m) LSC 8 (a) T T ( C) c(66) (m -1 ) [Chl] f (µg/l) (b) c(66) (c) [Chl] f Distance Southern End (km)

Results Partitioning of phosphorus loads Long-term variations in water quality Bill

19 Outline 1. Brief introduction to UFI 2. Phosphorus cycling in lakes 3. Contributing data sets 4. Results Partitioning of phosphorus loads Long-term variations in water quality Bill Hecht Impact of runoff events on water quality Flushing rate of southern Cayuga Lake Longitudinal patterns Synoptic surveys of the Finger Lakes 5. Summary 6. Questions

20 Flushing of the Shelf Enhanced by Upwelling Events Temperature ( C) (a) 24 (b) 25 upwelling event upwelling is promoted by strong sustained winds along the long axis of the lake APR MAY JUN JUL AUG SEP OCT

21 Finger Lakes Wide Studies: Cayuga Lake Chlorophyll (µg/l) Conesus Hemlock Canadice Honeoye Canandaigua Keuka Seneca th Cayuga Owasco Skaneateles Otisco Rankings, Chlorophyll monthly monitoring Chlorophyll (µg/l) Conesus Hemlock Canadice Honeoye Canandaigua Keuka Seneca 24 9 th Cayuga Owasco Skaneateles Otisco

1998-27 Lab total phosphorus soluble reactive phosphorus total dissolved phosphorus turbidity acidified

22 Program of Measurements Field temperature conductivity fluorescence beam attenuation irradiance scalar downwelling upwelling dissolved oxygen Secchi disc transparency April-October, bi-weekly, 9 sites, Lab total phosphorus soluble reactive phosphorus total dissolved phosphorus turbidity acidified turbidity total dissolved nitrogen ammonia nitrogen nitrate and nitrite nitrogen chlorophyll a chloride fecal coliform

Sources for Bottom Water Phosphates and Suspended Sediments in Southern Cayuga Lake, New York

Sources for Bottom Water Phosphates and Suspended Sediments in Southern Cayuga Lake, New York Prabighya Basnet Hobart & William Smith Colleges Geneva, NY Outline of Today s Presentation Introduce Problem