Limnology 101. PA AWWA SE District & Eastern Section WWOAP Joint Technical Conference October 13, 2016

Transcription

1 Limnology 1 PA AWWA SE District & Eastern Section WWOAP Joint Technical Conference October, 2 Kristen Bowman Kavanagh, P.E. Flow Science Incorporated

2 Limnology is the study of the biological, chemical, and physical features of lakes and other bodies of fresh water

3 Overview Why should we care about lake & reservoir water quality? What are the basic lake processes? What common management options are available? References Quiz

4 Why Should We Care about Lake & Reservoir Water Quality? Higher quality source water requires less treatment Clogging of filters Hazardous waste disposal Special treatment for tastes and odors

5 Why Should We Care about Lake & Reservoir Water Quality? (cont) Taste and odor problems lead to consumer complaints: Sulfides Ammonia Methane Geosmin MIB from algae Unprecedented algae bloom in Lake Mead in 21.

6 Why Should We Care about Lake & Reservoir Water Quality? Poor water quality can impair recreation and other beneficial uses and lead to degradation of aesthetics Fish kills Toxic algae

7 What are the Basic Lake Processes? Physical Surface heating & cooling Wind mixing Morphometry Inflow intrusions Chemical Oxygen dynamics Nutrients phosphorus, nitrogen, carbon Trace metals Biological Algae growth Thermal stratification affects water quality

8 Surface Heating & Cooling Wind Solar radiation Inflow Outflow

9 Lake Mixing Processes Turbulent mixing in surface layer (epilimnion) Mixing due to internal wave breaking at interface and thermocline seiching Mixing due to convective heating and cooling on a daily basis Mixing due to diffusion in the hypolimnion

10 Lake Morphometry Area, depth, volume, surface area, sediment area-tovolume ratio, orientation and wind fetch Not to Scale

11 Thermal Stratification epilimnion metalimnion/ thermocline hypolimnion Warm / Light Sharp Density Gradients Cold / Dense

12 Thermal Data vs. Stratification Simulation Station CR346.4 (cont) Depth (ft) Measured Temperature Temp. ( C) o 3 2 Depth (ft) 5 1/1/2 5/1/2 9/1/2 /31/2 Date 2 3 Predicted Temperature Physical behavior of reservoir determined by stratification Temp. ( C) o Water quality varies with elevation due to stratification 3 2

13 Thermal Data vs. Stratification Simulation Station CR346.4 (cont) Depth (ft) Measured Temperature Temp. ( C) o 3 2 Depth (ft) 5 1/1/2 5/1/2 9/1/2 /31/2 Date 2 3 Predicted Temperature Physical behavior of reservoir determined by stratification Temp. ( C) o Water quality varies with elevation due to stratification 3 2

14 Thermal Data vs. Stratification Simulation Station CR346.4 (cont) Depth (ft) Measured Temperature Temp. ( C) o 3 2 Depth (ft) 5 1/1/2 5/1/2 9/1/2 /31/2 Date 2 3 Predicted Temperature Physical behavior of reservoir determined by stratification Temp. ( C) o Water quality varies with elevation due to stratification 3 2

15 Thermal Data vs. Stratification Simulation Station CR346.4 (cont) Depth (ft) Measured Temperature Temp. ( C) o 3 2 Depth (ft) 5 1/1/2 5/1/2 9/1/2 /31/2 Date 2 3 Predicted Temperature Physical behavior of reservoir determined by stratification Temp. ( C) o Water quality varies with elevation due to stratification 3 2

16 Thermal Stratification (cont) temperature ( C) Station CR346.4 Data vs. Simulation for 2- at Station CR346.4 Comparison of Measured and Simulated Temperature at Surface Surface. 1/1/2 1/1/21 date 1/1/ 4. Comparison of Measured and Simulated Temperature at Bottom /31/ temperature ( C) Bottom. 1/1/2 1/1/21 date 1/1/ /31/ Data (USBR) Data (COLV) Data (SNWA) Simulation

17 Inflow Intrusions Intrusion level varies throughout year based on inflow density and reservoir stratification

18 Simulated Conductance on September, 2 Cond. Example: Inflow Intrusions Conductance vs. Distance Depth (ft) Depth (ft) Depth (ft) Measured Conductance on May 8, Distance Conductance from washvs. inflow Distance (km) 2 Measured Conductance on September, 2 Simulated Conductance on May 8, Distance 8 from wash inflow (km) 2 Distance from wash inflow (km) Cond. Cond. Cond

19 Example: Inflow Intrusions (cont) Conductance vs. Distance Depth (ft) Measured Conductance on November, Distance from wash inflow (km) 2 Cond epth (ft) 2 3 Simulated Conductance on November, 2 Cond

20 Chemical & Biological Processes

21 Dissolved Oxygen (DO) Dynamics epilimnion metalimnion/ thermocline hypolimnion Surface Aeration Prevents DO from Penetrating Hypolimnion No Photosynthesis Decomposers Consume O 2 Often Low DO/anoxic

22 Temperature & DO Relationship Lake Perris (1995) Lake Perris (1998) Measured Temperature at PE2 3 1/1 4/1 7/1 /1 /31 Date Measured Dissolved Oxygen at PE2 3 1/1 4/1 7/1 /1 /31 Date o Temp. ( C) DO (mg/l) Measured Temperature at PE2 3 1/1 4/1 7/1 /1 /31 Date Measured Dissolved Oxygen at PE2 3 1/1 4/1 7/1 /1 /31 Date o Temp. ( C) DO (mg/l)

23 DO in Anoxic Hypolimnion. Lake Perris Measured Dissolved Oxygen Concentrations (PE2). DO concentration (mg/l) est. max. depletion.2 mg/l/day 2. avg. depletion.8 mg/l/day. 1/1 4/1 7/1 /1 /31 Month 1998 (79 ft) 1997 (72 ft) 1996 (66 ft) 1995 (72 ft) 1986 (79 ft) 1985 (33 ft) 1984 (79 ft)

24 Internal Nutrient Loading epilimnion metalimnion hypolimnion Mixing Zone Prevents DO from Penetrating Hypolimnion Low DO/anoxic Hypolimnion PO 4 NH + 4 PO 4 NH + 4 sediments

25 Anoxic/Reducing Conditions epilimnion metalimnion hypolimnion Mixing Zone Prevents DO from Penetrating Hypolimnion Low DO/anoxic Hypolimnion H 2 S Fe CH 4 Mn

26 Algae (i.e., Phytoplankton) Measured as chlorophyll a Growth rate limited by light, phytoplankton internal phosphorus & internal nitrogen, and silica Phosphorus is often the limiting nutrient (also limited by temperature and light) Typical seasonal peaks in spring and at fall turnover Blue-green algae competitive advantages Can fix nitrogen from air Less heavily grazed (i.e., eaten) than other algae Contain gas bubbles to stay near surface

27 Carlson s Trophic State Index Oligotrophic low nutrients, low algal biomass, high clarity, dissolved oxygen throughout water column Mesotrophic moderate nutrients and algal biomass, some clarity Eutrophic rich in nutrients and algal biomass, turbid, loss of dissolved oxygen in hypolimnion during summer stratification Hypereutrophic very nutrient rich, high algal biomass levels have a negative impact on use

28 What In-Reservoir Management Options Are Available? Chemical treatment Careful design of inlet/outlet facilities Selective withdrawal Destratification Mechanical stirring Bubble plume Hypolimnetic oxygenation/aeration Partial lift Diffused oxygen Speece Cone

29 Mechanical Stirring Destratification Electric Supply Epilimnion Thermocline Power Cable Propeller Blade Angle Plate Hypolimnion Concrete Block Weight (typ.) Not to Scale Platform Propeller and Stand Stand and Superstructure Platform Base (typ.)

30 Bubble Plume Destratification Compressed Air Compressors Epilimnion Thermocline Compressed air supply line Hypolimnion - Diffuser line Not to Scale

31 Partial Lift Aeration Compressed Air Air vent Compressors Epilimnion Thermocline Compressed air supply line Hypolimnion Partial lift aeration unit Oxygenated water Not to Scale Not to Scale Compressed air acts like an air-lift pump, entraining oxygen-depleted water Discharge tube (typ.)

32 Partial Lift Aeration (cont) Reservoir Water Surface Air Vent Epilimnion Thermocline Hypolimnion Compressed Air Supply Release of Oxygenated Water (through diffuser) Entrainment/Inflow of Oxygen-depleted Water Not to Scale

33 Diffused Oxygen Input Gaseous Oxygen Epilimnion Liquid Oxygen Loading Liquid Oxygen Storage Tanks Ambient Vaporizers Thermocline Hypolimnion Oxygen supply line - Diffuser line Not to Scale

34 Speece Cone Oxygenation Electric Supply Gaseous Oxygen Epilimnion Liquid Oxygen Loading Liquid Oxygen Storage Tanks Ambient Vaporizers Thermocline Hypolimnion Oxygen supply line Electric supply line Oxygenated water Not to Scale Oxygen-depleted water enters Speece Cone through submersible pump Speece Cone Diffuser line Not to Scale

35 Design of Aeration System Upper Hollywood Reservoir Inlet EL 65 ft Site 4 #1 Sample Stations Partial Lift Units Compressor Units Supply Lines 2 3 Lower Hollywood Reservoir Effects of Aerator Operation Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove Without oxygenation DO (mg/l) #1 #2 #3 #4 #5 # #7 Site 3 #2 EL 594 ft #1 DAM Outlet Tower Site 1 Site 2 N 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # June 6, 23 With oxygenation Temp (C) Compressor: ON

36 Aeration System - Staging

37 Aeration System Stooging???

38 Towing Aerator into Position

39 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # June 6, 23 Temp (C) Compressor: ON

40 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # June, 23 Temp (C) Compressor: ON

41 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # June, 23 Temp (C) Compressor: ON

42 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # June, 23 Temp (C) Compressor: ON

43 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # June, 23 Temp (C) Compressor: ON

44 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # June, 23 Temp (C) Compressor: ON

45 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # June 17, 23 Temp (C) Compressor: ON

46 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # June 2, 23 Temp (C) Compressor: ON

47 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # June 27, 23 Temp (C) Compressor: OFF

48 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # July 1, 23 Temp (C) Compressor: OFF

49 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # July 3, 23 Temp (C) Compressor: OFF

50 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # July, 23 Temp (C) Compressor: OFF

51 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # July, 23 Temp (C) Compressor: OFF

52 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # July 29, 23 Temp (C) Compressor: OFF

53 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # September 29, 23 Temp (C) Compressor: OFF

54 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # September 3, 23 Temp (C) Compressor: ON

55 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # October 1, 23 Temp (C) Compressor: ON

56 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # October 2, 23 Temp (C) Compressor: ON

57 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # October 3, 23 Temp (C) Compressor: ON

58 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # October 4, 23 Temp (C) Compressor: ON

59 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # October 5, 23 Temp (C) Compressor: ON

60 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # October 6, 23 Temp (C) Compressor: ON

61 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # October 9, 23 Temp (C) Compressor: ON

62 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # October, 23 Temp (C) Compressor: ON

63 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # October, 23 Temp (C) Compressor: ON

64 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # October 2, 23 Temp (C) Compressor: ON

65 Lower Hollywood Reservoir Effects of Aerator Operation 2 3 Dissolved Oxygen Cross-Section from Outlet Tower to Northeast Cove DO (mg/l) #1 #2 #3 #4 #5 # #7 2 3 Temperature Cross-Section from Outlet Tower to Northeast Cove #1 #2 #3 #4 #5 #6 # October 23, 23 Temp (C) Compressor: ON

66 Aeration System in Operation at Hollywood Reservoir

67 References Limnology by Alexander Horne and Charles R. Goldman Limnology, Lake and River Ecosystems by Robert G. Wetzel Restoration and Management of Lakes and Reservoirs by G. Dennis Cooke, Eugen B. Welch, Spencer A. Peterson, and Stanley A. Nichols

68 For More Information. Kristen Bowman Kavanagh, P.E. Flow Science Incorporated Market St., Suite, PMB #52 Philadelphia, PA 192 Tel (2) Happy Halloween!