Physical limnology WETA151

1. Physical limnologyWETA151 L6 Pollution transport

2. Contents • Pollution? • Modes of pollution • point load and diffuse load • accidental and continuous • (Turbulence, advection and dispersion) • Pollutant jets and near field • Large scale transport • Diffusion equation • Case studies Timo Huttula

3. Pollution? • Water pollution: ”any addition to fresh or sea water that disrupts biological processes or causes a health hazard. • Common pollutants include nitrate, pesticides, and sewage (see sewage disposal), though a huge range of industrial contaminants, such as chemical byproducts and residues created in the manufacture of various goods, also enter water - legally, accidentally, and through illegal dumping.” Webster Timo Huttula

4. Pollutting substances (Lillesand&Kipfer, 1999) • Organic wastes • consume oxygen through decomposition • Infectious agents • transmit deceases • Plant nutrients • promote nuisance growth of aquatic plants like algae and water weeds • Synthetic organic chemicals • detergents and pesticides • toxic to aquatic life and potentially to humans • Inorganic chemical or mineral substances • from mining, manufacturing processes, oil plant operations and agricultural practices • interfere with natural stream purification, destroy aquatic life, cause excessive hardness of water supplies, produce corrosive effects Timo Huttula

5. Polluting substances.. • Sediments • fill streams, channels, harbours… • cause abrasion of hydroelectric power and pumping equipment, affect fish and shellfish population by blanketing fish nests and spawn as well their food supplies • Radioactive pollution • resulting from the mining and processing of radioactive ores, fallout of nuclear test… • Water temperature increases • by cooling waters • harmful effects on fish and aquatic life • reduce the capacity of the receiving water to assimilate wastes Timo Huttula

6. Modes of pollution entrainment: point source • Ex: Municipal sewage plant,Industrial sewage plan,River mouth Timo Huttula

7. Modes of pollution entrainment: diffuse load • Large and dispersed entrainment area: • Directly to lake with run off (agriculture, summer cottages, piers…) , Via small rivers and creeks around the lake, Atmospheric pollution directly to lake surface Timo Huttula

8. Modes of pollution entrainment: continuous • Treated waste water from treatment plants • In Finland the carrying capacity of recipient water is assessed before the permit is given • The amount and content is controlled by actor and occasionally by Environmental Administration • Loading amount (=volume*concentration) is reported and can be traced Timo Huttula

9. Modes of pollution entrainment:accidental • From industry • purification chemicals • over filling of tanks • From treatment plants • Sjas-river catastrophe in Russia • Sahalahti • From traffic • cyanide lorry on the shore of Lake Issyk-Kul • oil spillage on Baltic Timo Huttula

10. Turbulence, advection and dispersion • Laminar flow: • laminated structure • small velocities • Turbulent flow: • total velocity of water = mean velocity + chaotically fluctuating part of the flow • for each velocity component: f=f(mean)+f’ • most environmental flow outside micro scale are turbulent Timo Huttula

11. Importance of turbulence • Primary cause of mixing in lakes, molecular diffusion is about 9 orders of magnitude less than turbulent diffusion • Turbulence intensity is dependent on wind velocity, water density and currents in the lake • Turbulence spectrum consists of eddies of different sizes • Largest eddies are wind driven currents • The smallest eddies are dissipated by viscosity of the water Timo Huttula

12. 3.1.a: • -no flow in ambient water and incoming fluid lighter than ambient • -momentum jet • -rising plume • -level of equal density  horizontal spreading • 3.1.b: • -main flow present • -like 3.1.a but at the level of equal density advection downstream • 3.1.c: • -phases in the entrainment of a momentum jet • -development range • -fully developed flow Timo Huttula

13. Large scale (> 100 m and >1h) • Processes there determine the fate and transport of pollutant • Can be studied by map survey, measurements or numerical flow model application • Data on wind and river discharge are needed • Data on pollutant • temperature ? • density ? • aggregation ? • volatile ? Timo Huttula

14. Diffusion equation: simplest solution of transport • Where: M=released mass (kg), u=velocity of ambient flow (=advection) (m/s) , D=turbulent dispersion coefficient (m2/s), t=time (s), x=spatial coordinate (m) • Tracer concentration in (M=D=1 and u=0) at time t= 1 and 10 after release, which happened at origin. • Distribution is shown with one standard deviation . It grows as a function of time2 Timo Huttula

15. Lake Jyväsjärvi flow and particle transport model • Two dimensional simulation model for water currents • Vertical integration = mean velocity over the computational cell • Driving forces: wind, tributary flow • Resisting forces: internal and bottom friction • Bouyant particles (floating with currents) • Femflow2d.exe Timo Huttula

16. Lake Võrtsjärv • Present state and future fate of Lake Võrtsjärv. Results of Finnish-Estonian joint project in 1993-1997(Huttula and Nõges, eds., 1998) • Master plan for restoration and protection of Lake Võrtsjärv (Bilaletdin and Arvonen, 2000) Timo Huttula

17. Lake Võrtsjärv Timo Huttula

18. Simulated flowfields of Lake Võrtsjärv with particle tracking applications. • Wind: (a) - 4 m/s S , (b) - 4 m/s W , (c) - 4 m/s N , (d) - 4 m/s E. • Simulation time = 5 days, dispersion coefficient = 0.2 m2/s. • Source for particles is in the deepest part of the lake. Timo Huttula

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20. Oil spillage on Baltic • Ship traffic is increasing • Many companies try to minimize harbour payments by leaking spillage water to sea • Thin oil cover, floating on surface and transported by wind and currents • International collaboration for tracking the oil floats • control from air • using mathematical models Timo Huttula

21. Other examples • Päijänne Keljonlahti-Poronselkä • Onkivesi • Dem1 • Dem2 • Kokemäenjoki Timo Huttula