Hypolimnetic Oxygenation for Indian Creek Reservoir Restoration. Bill Faisst CA/NV AWWA Fall Conference October 22, 2014

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2 Hypolimnetic Oxygenation for Indian Creek Reservoir Restoration Bill Faisst CA/NV AWWA Fall Conference October 22, 14

3 Indian Creek Reservoir High desert lake Little runoff ~ acre foot volume Regulatory requirements (TMDL approved July 3) TMDL = Total Maximum Daily Limit

4 South Tahoe Public Utilities District Indian Creek Reservoir Constructed in mid-196 s Received South Tahoe effluent for plus years, to avoid harming Lake Tahoe but transferred lots of nutrients to ICR Converted to recreation only in ~199 Sustained with water from Carson River Showed water quality problems in 198 s (blue green algae blooms, low transparency and DO) Need to control Total P, DO and algae

5 Indian Creek Reservoir Location Lake Tahoe Nevada California

6 STPUD Project Goals Improve water quality and meet regulations (comply with TMDL) Preserve/enhance fishery Minimize visual impacts Control costs Carbon neutral?

7 Water Quality Indicator Parameters and Target Values (TMDL)

8 Facts about Water and Oxygen Highest water density is at 4C Saturation dissolved oxygen varies with temperature Higher DO at lower temperature Higher DO at higher pressure

9 Oxygen in Water Light in Water

10 What the heck is a hypolimnion? Lake Cross-Section

11 What happens in a lake or reservoir and why is DO important? Rain and atmospheric fallout (dust, mercury, NO x ) Stream runoff sediment nutrients, trace constituents (metals, organics) Organics P & N methylmercury sulfide Anoxic sediment

12 What happens at Indian Creek Reservoir?

13 ICR TMDL Monitoring Sites

14 ICR February 7 Profiles ICR-1 Temperature ICR-1 Dissolved Oxygen Depth, ft Temperature, C Depth, ft mg/l D.O. Isothermal, Cold Water at Maximum Density

15 ICR April Profiles ICR-1 Temperature ICR-1 Dissolved Oxygen Depth, f Depth, f Temperature, C mg/l D.O. Stratification Starts, DO Drops at Depth

16 ICR June Profile ICR-1 Temperature ICR-1 Dissolved Oxygen Depth, f Depth, f Temperature, C mg/l D.O. Water Warms, DO Falls

17 ICR July Profiles ICR-1 Temperature ICR-1 Dissolved Oxygen Depth, ft Temperature, C Depth, f Decreasing DO mg/l D.O. Strongly Stratified

18 ICR August Profiles ICR-1 Temperature ICR-1 Dissolved Oxygen Depth, f Strong Thermocline Depth, f No DO! Temperature, C mg/l D.O.

19 ICR September Profiles (after Fall Turnover) ICR-1 Temperature ICR-1 Dissolved Oxygen Depth, f Completely Mixed Depth, f DO to Bottom Temperature, C mg/l D.O.

20 ICR December Profiles ICR-1 Temperature ICR-1 Dissolved Oxygen Depth, f Depth, f Temperature, C mg/l D.O.

21 If hypolimnion becomes anoxic, what do you do? Mechanically mix the lake lots of energy, uniform temperature Aerate the lake lots of energy, uniform temperature Oxygenate the lake lots of oxygen, possibly uniform temperature Oxygenate the hypolimnion-focused oxygen, preserve stratification and colder bottom water

22 Oxygenate the hypolimnion? Soaker hoses Bubble plumes Speece cone

23 ICR HOS Project Requirements Needed about 1, lb/day of oxygen Had limited electrical service Reached by poor quality roads Couldn t interfere with recreation/fishery Needed low visual impacts Should be highly reliable and easy to operate

24 What is a good solution for ICR? Colder water for fish DO at depth for fish Summer stratification maintained DO control of nutrient cycling HOS with Speece Cone

25 ICR Bathymetry Dam

26 Speece cone fabrication at STPUD shop

27 Speece cone and diffuser during field assembly

28 Pipe installation in lake and across beach

29 Oxygen equipment (PSA system) and electrical service (PSA = Pressure Swing Absorption)

30 Depth, ft Depth, ft Depth, ft Depth, ft Depth, ft Depth, ft CA/NV AWWA Fall Conference 14 Did HOS help at ICR? 33 FT. ICR-1: 7 Dissolved Oxygen mg/l D.O. ICR-1: 8 Dissolved Oxygen mg/l D.O. ICR-1: 11 Dissolved Oxygen 48 FT mg/l D.O. ICR-1: 9 Dissolved Oxygen mg/l D.O. ICR-1: Dissolved Oxygen mg/l D.O. ICR-1 Dissolved Oxygen 43 FT mg/l 6D.O

31 Depth, ft Depth, ft Depth, ft CA/NV AWWA Fall Conference 14 February and September 12 Data ICR-1 Temperature Temperature, C ICR-1 Dissolved Oxygen mg/l D.O. ICR-1 Dissolved Oxygen mg/l D.O. Feb. Feb. Sept.

32 Depth, ft Depth, ft Depth, ft Depth, ft CA/NV AWWA Fall Conference 14 February and September 13 July 13 ICR-1 Temperature Temperature, C July ICR-1 Dissolved Oxygen mg/l D.O. September 13 ICR-1 Temperature Temperature, C September ICR-1 Dissolved Oxygen mg/l D.O.

33 Depth, ft Depth, ft CA/NV AWWA Fall Conference 14 New Data July 14 July 14 ICR-1 Temperature Temperature, C July 14 ICR-1 Dissolved Oxygen mg/l D.O.

34 Did HOS help at ICR?

35 Did HOS help at ICR?

36 Secchi Disk Used to measure water clarity

37 Did HOS help at ICR?

38 Did HOS help at ICR?

39 Carlson Trophic State Index TI Chl P SD Trophic Class < >8 4 Oligotrophic Mesotrophic Eutrophic <. Hypereutrophic

40 Did HOS help at ICR Trophic State Index?

41 Conclusions TP decreased.7 to.3 mg/l DO increased--> 6. mg/l Secchi disk depth improved~1. to ~4 m Chlorophyll a decreased > fold HOS operation addressed TMDL requirements

42 Is HOS important beyond algae? Control Program for Mercury in California s Reservoirs

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44 Speece Cone for ICR

45 HOS Schematic

46 What happens to a bubble in water? Drag Buoyancy O 2 dissolves in water Smaller bubbles rise more slowly = more time Bubble shrinks More time = more O 2 transfer Smaller bubbles = more surface area/unit volume

47 Problem solution integrates multiple disciplines under the lead of a civil/environmental engineer or geologist Limnologist Oceanographer Geotechnical engineer/diver Civil engineer Structural engineer Electrical engineer Instrumentation engineer Environmental specialist Green energy specialist