QUAL2K You’ve heard of QUAL2E - download.water.miau.irdownload.water.miau.ir/software/q2k/q2k-ambrose.pdf · Developed by Steve Chapra for 2004 QUAL2K Workshop (Some slides have

Developed by Steve Chapra for 2004 QUAL2K Workshop (Some slides have been updated)

You’ve heard of Mike11

You’ve heard of QUAL2E

You’ve heard of HSPF

THE TMDL TERMINATOR

Coming soon to your Watershed

QUAL2K


QUAL2K WORKSHOP: INTRODUCTION*

Steve Chapra Tufts University

!   Rationale and Overview !   Segmentation and Hydraulics

* Abbreviated for Region 6 Modeling Workshop, November 2013, by Robert Ambrose


QUAL2K •  Fast C (BOD), Slow C (BOD), organic N,

NH3, NO3, organic P, SRP, oxygen, phytoplankton, FIXED PLANTS, suspended solids, conservative/color

•  Heat budget

•  Point and distributed loads and abstractions

•  Steady-state, 1-D Mainstem River


  Shuts down oxidation at low DO

  SOD and sediment nutrient fluxes calculated

  Denitrification

  Speciates carbon

  Fixed plants

  Anoxia

QUAL2K


QUAL2K !   Software environment and interface !   Model segmentation !   Carbon speciation !   Anoxia and denitrification !   Sediment-water interactions !   Bottom plants !   Light extinction !   pH !   Pathogens


QUAL2K Documentation

1

2

3

4 5

6

8

7

Non - point abstraction

Non - point source

Point source

Point source

Point abstraction

Point abstraction

Headwater boundary

Downstream boundary

Point source

SEGMENTATION

i i + 1 i - 1 Qi-1 Qi

Qin,i Qab,i

FLOW BALANCE

Qi = Qi-1 + Qin,i – Qab,i

Q npt

25% Q npt 25% Q npt 50% Q npt

start end

DISTRIBUTED (NON-POINT) LOADS


B

D

E

F C

G

QA QC QF QE QD QB QG

A

Upstream Lake

STEADY-STATE FLOW BALANCE


WHAT HAPPENS WHEN YOU ADD FLOW TO A SLOPING CHANNEL?

The water velocity and depth increase

Given Qoutflow, compute depth (H) and velocity (U): •  Continuity and Manning equation •  Rating Curves


RATING CURVES

1

10

100 500 Q (m 3 /s)

H (m)

0.1

1

100 500 Q (m 3 /s)

U (m/s)

H = 1.6487 Q 0.1622 U = 0.0279 Q 0.5652


Ac = Q/U B = Ac /H As = Δx B

V = B H Δx τw = Δx / U = V/Q

Q

Manning Rating Curves

U, H

RIVER HYDROGEOMETRY (STEADY)


B

D

E

F C

G

QA QC QF QE QD QB QG

A

Upstream Lake

STEADY-STATE FLOW BALANCE

Rating Curve

Rating Curve

Manning Manning


LONGITUDINAL DISPERSION

U gHS * =

E U B

HU = 0 011

2 2

. *


QUAL2K WORKSHOP: TEMPERATURE MODELING

!   Heat Balance

!   Meteorological Data !   Surface Heat Flux

!   Sediment Heat Flux !   Air-Water Converter


Q2K

i inflow outflow

dispersion dispersion

heat load heat abstraction

atmospheric transfer

sediment-water transfer

sediment


SURFACE HEAT BALANCE

air-water interface

solar shortwave radiation

atmospheric longwave radiation

water longwave radiation

conduction and

convection

evaporation and

condensation

water-dependent terms net absorbed radiation

non-radiation terms radiation terms


ANNUAL SOLAR RADIATION

Summer Solstice

Winter Solstice

Lat = 24O

Havana/Sao Paolo

Lat = 64O

Reykjavik, Iceland

0

200

400

600

800

1-Jan 1-Mar 1-May 1-Jul 31-Aug 31-Oct 31-Dec

cal cm2 d


DAILY SOLAR RADIATION

0

500

1000

1500

2000

0 6 12 18 24

Winter solstice

Summer solstice

Equinox


WHAT YOU NEED??? (METEOROLOGICAL DATA)

( )

) )( ( ) )( ( 15 273 (

) 1 ( 031 . 0 15 273 (

air air 1 4

4 air

e e U f T T U f c ) . T

R e A ) . T J J

s w s w s

L air sn

- - - - + -

- + + + =

εσ

σ

Solar (Cloud Cover)

Air Temperature

Dew Point Temperature

Wind Speed


SEDIMENT HEAT BUDGET

Ts,i

( ) si i s

s i s T T

H J - =

α

,

si p

i s i s

H C

J

dt

dT =

ρ

, ,

Ti


Q2K WATER QUALITY Variable Symbol Units* Conductivity s µmhos Inorganic suspended solids mi mgD/L Dissolved oxygen o mgO2/L Slowly reacting CBOD cs mgO2/L Fast reacting CBOD cf mgO2/L Organic nitrogen no µgN/L Ammonia nitrogen na µgN/L Nitrate nitrogen nn µgN/L Organic phosphorus po µgP/L Inorganic phosphorus pi µgP/L Phytoplankton ap µgA/L Phytoplankton nitrogen INp µgN/L Phytoplankton phosphorus IPp µgP/L Detritus mo mgD/L Pathogen X cfu/100 mL Alkalinity Alk mgCaCO3/L Total inorganic carbon cT mole/L Bottom algae biomass ab mgA/m2 Bottom algae nitrogen INb mgN/m2 Bottom algae phosphorus IPb mgP/m2 Constituent i Constituent ii Constituent iii


i inflow outflow

dispersion dispersion

mass load mass abstraction

atmospheric transfer

bottom algae sediments

i i

i S V

W + + ( ) ( ) i i i

i i i

i

i c c V

E c c V

E - + - + + - -

1

'

1

' 1

i i

i ab i

i

i i

i

i i c V

Q c

V

Q c V

Q

dt dc - - = -

- , 1

1

i i

i S V

W + + ( ) ( ) i i i

i i i

i

i c c V

E c c V

E - + - + + - -

1

'

1

' 1

i i

i S V

W + + ( ) ( ) i i i

i i i

i

i c c V

E c c V

E - + - + + - -

1

'

1

' 1 ( ) ( ) i i

i

i i i

i

i c c V

E c c V

E - + - + + - -

1

'

1

' 1

i i

i ab i

i

i i

i

i i c V

Q c

V

Q c V

Q

dt dc - - = -

- , 1

1 i

i

i ab i

i

i i

i

i i c V

Q c

V

Q c V

Q

dt dc - - = -

- , 1

1

i b i b S

dt da

, , = i b i b S

dt da

, , =

MASS BALANCE


PHYTOPLANKTON AND DETRITUS STOICHIOMETRY:

The “Redfield Ratio”

100% : 40% : 7.2% : 1% : 0.5-2.0%

D : C : N : P : A


TEMPERATURE EFFECT ON THE REACTION RATE

k ( T )

k (20)

0

1

2

3

4

0 T ( o C)

10 20 30

θ = 1 θ = 1.024

θ = 1.047

θ = 1.08

θ = 1.1

θ = 1.07

biotic

gas transfer

k T k T ( ) ( ) = - 20 20 θ


Q2K CHEMISTRY AND pH MODELING

!   Mass Balance versus Chemical Equilibria Models

!   Ammonia-Ammonium Acid Base !   pH Modeling

!   Chemistry 101


THE CHEMISTRY PERSPECTIVE: AMMONIA ACID-BASE EQUILIBRIUM

H NH NH 3 4

+ + + H NH NH 3 4

+ + +

] = ] H ][ NH [ 3 +

b k ] H ][ NH [ 3 +

b k NH [ 4 +

f k NH [ 4 +

f k

NH3 NH4+

kf

kb

H+


FAST REACTIONS

FOOD CHAIN

P R

SLOW REACTIONS

V

inorganic carbon CO 3 2- HCO 3 - H 2 CO 3 *

pH MODELING


Q2K PLANTS

!   Phytoplankton

!   Stationary or Attached Plants


da

dt k a g =

a a t

a a e o k t g

=

=

if at = 0 0

t , d 0 1 10 100

a , mg m -3 1 7.8 4.85x10 8 7.2x10 86

da dt

k T N I a k a g d = - ( , , )

k T N I k g g T N L = ( , , ) , φ φ

temperature nutrients light

Incorporating Limits to Growth


TEMPERATURE DEPENDENCY

k g , T (d -1 )

T ( o C) T min T opt T max

k g ,opt k g ,20

0

2

4

6

8

0 20 40

Theta model θ = 1.066

linear

optimal


0

0.5

1

0 N k s

φ N

φ N s

N k N

= +

NUTRIENT LIMITATION MICHAELIS-MENTEN KINETICS

Half-saturation Constant


Light Response Models for Plant Growth

0

0.5

1

0 200 400 600 800 Light ( langley /d)

Mich - Ment Photinhib Smith

: Model Menten ) - ( Michaelis Saturation

si I k I +

= φ

: Model Menten ) - ( Michaelis Saturation

si I k I +

= φ

1

: Model ition Photoinhib

I I

s e

I I s =

- φ

1

: Model ition Photoinhib

I I

s e

I I s =

- φ

2 2

: Model Smith

k I I

I

+ = φ 2 2

: Model Smith

k I I + = φ


( c ) Dependence of growth rate

on light

I

z

( b ) Light attenuation with depth

mixed layer

( a ) Diurnal variation of

light t

I

midnight noon midnight

I

k g

IMPACT OF LIGHT ON

PHOTOSYNTHESIS


STATIONARY OR “ATTACHED” PLANTS

!   Overview

!   Macrophytes !   Simple Periphyton Modeling


Differences between fixed and floating plants

Types Diatoms Greens Blue Greens

Periphyton Filamentous Algae

Rooted Macrophytes Units mgchl a/m3 gD/m2 or mgA/m2

Light Average Water Column Bottom Light

Transport Yes No

Predation Zooplankton Insect Larvae, Snails, etc.

Floating Attached

Substrate Not an issue Rock vs. Mud


Functional Groups

  Macrophytes: Vascular, Rooted Plants   Myriophyllum, Elodea, Potamogeton

  Periphyton: algae attached to and living upon submerged solid surfaces   Diatoms, Greens, Blue Greens

  Filamentous Algae   Cladophora


Phytoplankton:

+ transport - settling

p d p r p n l g p a k a k a T k

dt

da - - = φ φ ) (

Based on integral light

f d f r n l max f a k a k T G

dt

da - - = φ φ ) (

Periphyton: Based on bottom light

PERIPHYTON MODELS


EFFECT OF LIGHT ON PERIPHYTON

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( a ) floating plants

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( b ) periphyton


Macrophytes

  Can get nutrients from roots

  Can extend up into water column

  Lakes/Slow-moving streams/shallow rivers

  Myriophyllum, Elodea, Potamogeton (Water milfoil) (Waterweed) (Pondweed Oxygen weed)

  Vascular, Rooted Plants


Q2K SEDIMENT/WATER

INTERACTIONS

!   Sediment Oxygen Demand

!   Diffusion/Reaction Competition

!   Methane Bubble Formation

!   Numerical Methods


sediments

water

air

SEDIMENT-WATER PROCESSES “THE MISSING LINK OF WATER-QUALITY MODELLING”

Organic Matter

Organic Matter

Oxygen Nutrients

SOD N, P

Fluxes

SEWAGE, RUNOFF PHOTOSYNTHESIS

?


1.5 Estuarine mud 4

1.5 Municipal sewage sludge outfall vicinity downstream of outfall, "aged"

2-10 1-2 1-2

0.5 0.07

Sandy bottom Mineral soils Areal hypolimnetic oxygen demand

(AHOD) -- lakes

0.2-1 0.05-1 0.06-2

TYPICAL SOD VALUES S B , '

20 (g m -2 d -1 ) Average value Bottom type and location Range

2 7 Sphaerolitus (10 g dry wt/m ) - 5 Zebra Mussels (6000 individuals/m2) -


SOD (g/m 2 /d)

0

4

8

0 100 200

COD (mgO/L)

THE “SQUARE-ROOT” RELATIONSHIP OF SEDIMENT OXYGEN DEMAND

AND OVERENRICHMENT

SOD = α COD0.5


WHY NONLINEARITIES MATTER

/d) 60

SOD (gO/m 2 /d)

Downward Flux of Organic Carbon (gO/m 2

0

2

4

6

0 20 40

Zero-order fiction The “Environmentalist’s Dream”

Nonlinear reality


WHERE DOES NONLINEARITY COME FROM?

!   Loss of carbon as methane gas in anaerobic sediments

!   Competition between reaction and diffusion in aerobic surface sediment


!   Seems like a lot of parameters

!   For steady state, really only three

CALIBRATION

!   Mass transfer, vd01 !   Reaction rates, kn1 + kc1

Modified for Region 6 Modeling Workshop, November 2013, by Robert Ambrose



Boulder Creek Example

!   Create a folder: C:/Q2K

!   Files Q2KMaster*.xls and q2kfortran*.exe should be in this folder

!   Create a folder: C:/Q2K/DataFiles

!   Unzip Q2K*.zip in this folder



!   Change Saved File Name to Boulder Creek

!   Change Directory where file stored to C:/Q2K/DataFiles

!   Click Run Fortran button


Boulder Creek Example

!   Launch Q2KMaster.xls

QUAL2K You’ve heard of QUAL2E - download.water.miau.irdownload.water.miau.ir/software/q2k/q2k-ambrose.pdf · Developed by Steve Chapra for 2004 QUAL2K Workshop (Some slides have

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