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Hydrodynamics and Environmental Impacts of a Coastal Lake in Chile

This case study focuses on the hydrodynamics of a coastal lake in Southern Chile and its impact on the water environment and human needs. It explores aspects of transport and mixing in stratified flows, discussing theoretical concepts and practical applications through experiments and numerical modeling. The study also addresses social and environmental issues related to the lake, including the decline of fishing and forced land-use changes for agriculture.

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Hydrodynamics and Environmental Impacts of a Coastal Lake in Chile

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  1. Ingeniería Civil THE WATER ENVIRONMENT AND HUMAN NEEDS: A CASE STUDY INVOLVING THE HYDRODYNAMICS OF A COASTAL LAKE IN SOUTHERN CHILE Yarko Niño Department of Civil Engineering, Universidad de Chile

  2. THE WATER ENVIRONMENT AND HUMAN NEEDS … THIS WIDER SCOPE OF APPROACHING FUTURE PROBLEMS OF THE WATER ENVIRONMENT … WHEN ALL THE COMPLEX ENVIRONMENTAL AND SOCIAL FACTORS MUST BE CONSIDERED IN A GIVEN SYSTEM TO MEET THEM WITH CREATIVE IDEAS AND TECHNOLOGY AT PRESENT STILL LARGELY UNKNOWN … (A.T. IPPEN, 1970)

  3. THE PLAN EXPLORE A SYSTEM WHOSE HYDRODYNAMICS HAS A STRONG IMPACT ON THE ENVIRONMENT AND WELL-BEING OF LOCAL COMMUNITIES IN THE PROCESS DISCUSS ASPECTS OF TRANSPORT AND MIXING IN STRATIFIED FLOWS GO FROM THEORY TO PRACTICE (THROUGH EXPERIMENTS AND NUMERICAL MODELING)

  4. THE SYSTEM

  5. BUDI RIVER MOUTH LAKE BUDI 38º 52` 73º 22` THE SYSTEM RIVER AND LAKE BUDI 15 km

  6. 0 DEPTH (m) 4 8 14 16 18 20 24 26 22 28 SALINITY (pss) DISTANCE (km) 0 DEPTH (m) 4 14 16 18 20 22 24 26 28 8 DISTANCE (km) DISSOLVED OXYGEN (mg/l) THE SYSTEM SALINITY STRATIFICATION AND DISSOLVED OXYGEN

  7. THE SYSTEM BUDI RIVER MOUTH (ICOL)

  8. THE SYSTEM ARTIFICIAL OPENING

  9. THE SYSTEM ARTIFICIAL OPENING

  10. SOCIAL AND ENVIRONMENTAL ISSUES LAKE BUDI IS LOCATED IN A REGION OF LOW-INCOME RURAL NATIVE PEOPLE (MAPUCHE) COMMUNITIES MAIN ECONOMIC ACTIVITIES ARE SMALL-SCALE FISHING AND AGRICULTURE IN RECENT YEARS FISHING IN THE LAKE HAS DECLINED FORCING LAND-USE CHANGES FOR AGRICULTURE  THIS HAS FORCED EARLIER IN THE YEAR AND MORE FREQUENT OPENINGS OF THE MOUTH BAR AND DECAYING WATER QUALITY IN THE LAKE

  11. RIVER AND LAKE SALINITY INTRUSION DYNAMICS

  12. OCTOBER 2 (3 DAYS PRIOR 2ND OPENING ) OCTOBER 18 (2 WEEKS AFTER 2ND OPENING ) DECEMBER 12 (10 WEEKS AFTER 2ND OPENING ) JANUARY 29 (17 WEEKS AFTER 2ND OPENING ) RIVER AND LAKE SALINITY INTRUSION DYNAMICS FIELD OBSERVATIONS 2006-2007 2 MOUTH-BAR OPENINGS IN THE AUSTRAL WINTER OF 2006: JUNE 22 AND OCTOBER 5

  13. 0 2 4 6 8 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 18 16 14 12 10 8 6 4 SALINITY (pss) RIVER AND LAKE SALINITY INTRUSION DYNAMICS SALINITY STRUCTURE PRIOR 2ND OPENING OCTOBER 2 Z (m) DISTANCE (km)

  14. 0 2 4 6 8 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 18 16 14 12 10 8 6 4 SALINITY (pss) RIVER AND LAKE SALINITY INTRUSION DYNAMICS SALINITY STRUCTURE 2WEEKS POST 2ND OPENING OCTOBER 18 Z (m) DISTANCE (km)

  15. 0 2 4 6 8 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 18 16 14 12 10 8 6 4 SALINITY (pss) RIVER AND LAKE SALINITY INTRUSION DYNAMICS SALINITY STRUCTURE 10 WEEKS POST 2ND OPENING DECEMBER 18 Z (m) DISTANCE (km)

  16. 0 2 4 6 8 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 18 16 14 12 10 8 6 4 SALINITY (pss) RIVER AND LAKE SALINITY INTRUSION DYNAMICS SALINITY STRUCTURE 17 WEEKS POST 2ND OPENING JANUARY 29 COMPLETE MIXING! Z (m) DISTANCE (km)

  17. SALINITY INTRUSION: PLUNGING AND DENSITY CURRENT

  18. PLUNGING POINT i Qi h a U SALINITY INTRUSION: PLUNGING AND DENSITY CURRENT

  19. PLUNGING POINT i Qi h a U SALINITY INTRUSION: PLUNGING AND DENSITY CURRENT ELLISON & TURNER (1959)

  20. PLUNGING POINT i Qi h a U SALINITY INTRUSION: PLUNGING AND DENSITY CURRENT ELLISON & TURNER (1959)

  21. SALINITY INTRUSION: PLUNGING AND DENSITY CURRENT DENSITY CURRENT IN THE LAKE (2 WEEKS POST 2ND OPENING) FREE SURFACE Z (m) DENSITY CURRENT FIELD OBSERVATIONS 10 5 15 20 25 DISTANCE (km)

  22. SALINITY INTRUSION: PLUNGING AND DENSITY CURRENT EXCHANGE FLOWS DAILY MEAN FLOW RATES SALINITY (PSS) FRESH INFLOW Q (m3/s) SALTY INFLOW OUTFLOW DATE

  23. MIXING IN STRATIFIED FLUID

  24. u* 1 h1 2 h2 MIXING IN STRATIFIED FLUID WIND MIXING IN TWO-LAYER FLUID WIND RICHARDSON NUMBER

  25. DENSITY MAPS,Ri* = 82.6 t = 0 t = 3 min ENTRAINMENT VELOCITY t = 15 min t = 50 min t = 120 min MIXING IN STRATIFIED FLUID EXPERIMENTS (NIÑO ET AL., 2003)

  26. ue/u* Ri* MIXING IN STRATIFIED FLUID EXPERIMENTS (NIÑO ET AL., 2003) (KRANENBURG, 1985; MONISMITH, 1986)

  27. MIXING IN STRATIFIED FLUID LET’S DO SOME THEORY IPPEN’S STYLE (e.g., HARLEMAN & IPPEN, 1966)

  28. BULK MIXING EFFICIENCY (TSENG & FERZIGER, 1998) GAIN IN PE FRICTION FACTOR WIND INPUT (0.2%) MIXING IN STRATIFIED FLUID

  29. MIXING IN STRATIFIED FLUID LET’S TRY A DIFFERENT APPROACH!

  30. MIXING EFFICIENCY TURBULENT DIFFUSIVITY MIXING IN STRATIFIED FLUID TKE BALANCE  0.15 (WÜEST & LORKE, 2003)

  31. S1 h1 u* S2 h2 MIXING IN STRATIFIED FLUID VALUE?

  32. z/H u/us z/H K/us2 MIXING IN STRATIFIED FLUID K- MODEL WITH BUOYANCY EFFECTS VELOCITY TKE

  33. u/us z/H MIXING IN STRATIFIED FLUID K- MODEL WITH BUOYANCY EFFECTS

  34. MIXING IN LAKE BUDI

  35. z/H S (pss) MIXING IN LAKE BUDI ENTRAINMENT VELOCITY

  36. WIND VELOCITY (m/s)  ue/u* 210-5 Ri* 2.2104 MIXING IN LAKE BUDI ENTRAINMENT VELOCITY

  37. ue/u* Ri* MIXING IN LAKE BUDI 

  38. 0 DEPTH (m) 4 8 14 16 18 20 24 26 22 28 DISTANCE (km) MIXING IN LAKE BUDI MIXING DUE TO BENTHIC BOUNDARY LAYER TURBULENCE

  39. SIMULATION OF LAKE BUDI HYDRODYNAMICS

  40. SALINITY (pss) SIMULATION OF LAKE BUDI HYDRODYNAMICS MODELING SALINITY INTRUSION AND MIXING OPEN

  41. DISSOLVED OXYGEN CONCENTRATION (mg/l) SIMULATION OF LAKE BUDI HYDRODYNAMICS MODELING DISSOLVED OXYGEN CONCENTRATION OPEN

  42. DENSITY (kg/m3) DISSOLVED OXYGEN CONCENTRATION SIMULATION OF LAKE BUDI HYDRODYNAMICS PREDICTION IN THE CASE OF NATURAL MOUTH BAR OPENING OPEN OPEN

  43. FINAL REMARKS PRESENT MOUTH BAR MANAGEMENT WOULD NOT BE COMPATIBLE WITH FISH ECOLOGICAL DYNAMICS BETTER PRACTICE MUST COMPATIBILIZE FLOODING PROTECTION, WATER QUALITY, LAKE ECOLOGY, AND LOCAL COMMUNITIES WELFARE RESEARCH IS FUN BUT IS MORE FUN WHEN IT IS PUT AT THE SERVICE OF PROTECTING AND IMPROVING SOCIAL AND ENVIRONMENTAL CONDITIONS

  44. THANKS TO: FELIPE SANDOVAL CLAUDIA RODRIGUEZ MANUEL CONTRERAS

  45. Re* ≈ 3104  I ≈ 0.15 LAKE BUDI Ri* ≈ 2104 Li/h1 ≈ 0.2 MIXING IN LAKE BUDI TURBULENT INTENSITY PARAMETER (IVEY ET AL., 2008) EXPERIMENTS NIÑO ET AL. (2003): I≈ 1-15 WUEST & LORKE (2005): I≈ O(1) AT LAKES THERMOCLINE

  46. I RANGE REGIME I < 7 MOLECULAR TRANSITIONAL 7< I < 100 I > 100 ENERGETIC MIXING IN LAKE BUDI TURBULENT INTENSITY PARAMETER (IVEY ET AL., 2008) CHECK! MIXING DUE TO BENTHIC BOUNDARY LAYER TURBULENCE

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