(Chapra, L26 & L29) David Reckhow CEE 577 #27 1 Mechanistic - PowerPoint PPT Presentation

Updated: 28 March 2013 Print version Lecture #27 Limnology (cont.): Other Mechanistic Models (Chapra, L26 & L29) David Reckhow CEE 577 #27 1

Mechanistic Nutrient Models  Qual2E/Qual2K  Rivers: 1 dimensional  DOC compartments expanded in 2K – like WQMCB  CE-QUAL-W2  Reservoir, Estuary: 2 dimensional (longitudinal-vertical)  Cannonsville Reservoir Model  WQDPM (Water Quality Diss. Part. Model)  3 dimensional  Coupled to GLLVHT Hydrodynamics  Generalized Longitudinal Lateral Vertical Hydrodynamic and Transport model  11 constituents  Separates Org-N and Org-C into dissolved and particulate David Reckhow CEE 577 #27 2

Atmosphere General Qual2E (K a ) K 2 Kinetics K 4 α ρ σ 4 SOD 1 Organic N K 1 (K s ) Dissolved Oxygen K 3 β 3 CBOD (K d ) α µ σ 3 1 F NH 3 β α β α ρ 1 σ 5 5 1 2 NO 2 Org-P β 2 β 4 σ 2 α 6 β 2 NO 3 Diss-P α µ − F ( 1 ) α µ α ρ 1 α µ α µ 3 4 2 1 Chlorophyll a (Algae) σ 1 David Reckhow CEE 577 #21 3

Qual2K version re re r da r da ds ds h h c T c T c T o o o r od r od c s c s c f c f m o m o cf cf sod sod c T c T se se ox ox s s X X ox ox o o s s o o s s c T c T m i m i h h n n dn dn Alk Alk r na r na s s n a n a n n n n n o n o se se s s se se c T c T d d p p o o u u IN IN h h r pa r pa a a p o p o p i p i s s IP IP u u s s s s se se r r o o e e e e c T c T Kinetic processes are dissolution (ds), hydrolysis (h), oxidation (ox), nitrification (n), denitrification (dn), photosynthesis (p), respiration (r), excretion (e), death (d), respiration/excretion (rx). Mass transfer processes are reaeration (re), settling (s), sediment oxygen demand (SOD), sediment exchange (se), and sediment inorganic carbon flux (cf) David Reckhow CEE 577 #27 4

Q2K state Variables Variable Symbol Units* µ mhos Conductivity s D, C, N, P, and A refer to dry Inorganic suspended solids mgD/L m i weight, carbon, nitrogen, Dissolved oxygen mgO 2 /L o phosphorus, and chlorophyll a , Slowly reacting CBOD mgO 2 /L c s respectively Fast reacting CBOD mgO 2 /L c f µ gN/L Organic nitrogen n o µ gN/L Ammonia nitrogen n a µ gN/L Nitrate nitrogen n n µ gP/L Organic phosphorus p o Note: µ gP/L Inorganic phosphorus p i µ gA/L • fast and slow CBOD Phytoplankton a p µ gN/L Phytoplankton nitrogen IN p • dissolved P is now inorganic P µ gP/L Phytoplankton phosphorus IP p • nitrite is dropped Detritus mgD/L m o Pathogen cfu/100 mL X Total inorganic carbon mole/L c T mgA/m 2 Bottom algae biomass a b Bottom algae nitrogen mgN/m 2 IN b Bottom algae phosphorus mgP/m 2 IP b David Reckhow CEE 577 #27 5

“The sediments are divided into 2 layers: a thin ( ≅ 1 mm) surface aerobic layer Q2K Sediment Model underlain by a thicker (10 cm) lower anaerobic layer.” WATER J pom c f o n a o n n p i “Organic carbon, nitrogen AEROBIC and phosphorus are delivered CH 4 CO 2 NH 4p NH 4d NO 3 N 2 PO 4p PO 4d to the anaerobic sediments via the settling of particulate organic matter (i.e., CH 4 (gas) POC phytoplankton and detritus). There they are transformed ANAEROBIC by mineralization reactions PON NH 4p NH 4d NO 3 N 2 into dissolved methane, ammonium and inorganic phosphorus. These PO 4p PO 4d POP constituents are then transported to the aerobic layer where some of the methane and ammonium are DIAGENESIS METHANE AMMONIUM NITRATE PHOSPHATE oxidized. The flux of oxygen from the water required for these oxidations is the From Chapra, Pelletier & Tao, 2008 sediment oxygen demand.” David Reckhow CEE 577 #27 6

Cannonsville Model Phosphorus Zooplankton Nitrogen Dissolved O 2 Phytoplankton David Reckhow CEE 577 #27 7

WQDPM Model From: Edinger, 2002, Waterbody Hydrodynamic and Water Quality Modeling, ASCE Press David Reckhow CEE 577 #27 8

From: Edinger, 2002, Waterbody Hydrodynamic and Water WQDPM Model Quality Modeling, ASCE Press David Reckhow CEE 577 #27 9

Higher-Order Carbon Model  WQMCB  Expands organic carbon fractions –  adopted for use by new QUAL2K visual basic version  Fast-reacting (dissolved and particulate)  Slow-reacting (dissolved and particulate)  Refractory (particulate only)  14 constitutents David Reckhow CEE 577 #27 10

WQMCB model From: Edinger, 2002, Waterbody Hydrodynamic and Water Quality Modeling, ASCE Press David Reckhow CEE 577 #27 11

From: Edinger, 2002, Waterbody Hydrodynamic and Water Quality Modeling, ASCE Press WQMCB model David Reckhow CEE 577 #27 12

 To next lecture David Reckhow CEE 577 #27 13