the TRIM model - Massey University

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11 Feb 2013 ... Can LU intensification be N/P neutral or better? ... Runoff – quick flow ... Tukituki at Tapairu Rd. TRIM observed. 0. 20. 40. 60. 80. 100. 1960.
Solution to Pollution – 11th February 2013, Massey University

Land use, nutrients and periphyton in the Tukituki River – the TRIM model Kit Rutherford NIWA, 82 Ford Rd, Napier

Acknowledgements NIWA: John Quinn, Bob Wilcock, Niall Broekhuizen HBRC: Adam Uytendaal, Husam Baalousha, Dougal Gordon, Ian Millner, Barry Lynch , Rob Waldron, Monique Benson Cawthron: Roger Young GNS-Science: Mike Toews, Maksym Gusyev …and uncle Tom Cobbley

Management questions Can LU intensification be N/P neutral or better? Can on-farm mitigation be done cost-effectively? Can WWTP upgrades be done cost-effectively? Are there other mitigations (eg dam releases)? Do we need to control N or P, or both? Etc…….

Scientific challenge – quantify the links between • on-farm & in-city practices • river nutrients, plants and health?

Catchment BNZ, GLEAMS E2 INCA SWAT CLUES

Farms OVERSEER (annual) SPASMO & APSIM (daily)

ROTAN

Streams Groundwater Tritium ageing MODFLOW (flow) FEM-WATER (flow, nitrogen)

QUAL2e, RIVMOD Periphyton Guidelines SPASM, SAL (daily)

TRIM_CATCHMENT • •

AGRIBASE (land use) OVERSEER (annual N/P losses) • Drainage – slow flow • Runoff – quick flow

Enter the TRIM model… TRIM_CATCHMENT Slow flow • MODFLOW groundwater catchments, lags • Groundwater attenuation Quick flow • Nearest stream – no lags • Attenuation Annual N and P stream inflows

Daily inflows statistical estimates based on monthly monitoring 1994-2012

TRIM_STREAM (daily) • • •

Dilution, scour, advection Nutrient spiraling Periphyton growth

𝑃𝑃𝑃𝑃𝑃𝑃 = 𝑎𝑎𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 −𝑏𝑏 𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 2

y = 2240x-1.155 R² = 0.94

PET/Rainfall

1.5

Penman PET Priestley Taylor PET

1 y = 2130x-1.164 R² = 0.93

0.5

𝑃𝑃𝑃𝑃𝑃𝑃 𝐴𝐴𝐴𝐴𝐴𝐴 𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 = 𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 1 + 𝑤𝑤 𝑃𝑃𝑃𝑃𝑃𝑃 + 𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 𝑃𝑃𝑃𝑃𝑃𝑃 1 + 𝑤𝑤

0 0

500

1000 Rainfall (mm/y)

1500

𝑃𝑃𝑃𝑃𝑃𝑃 𝑤𝑤 1 + 𝐴𝐴𝐴𝐴𝐴𝐴 𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 = 𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 1 + 𝑤𝑤 𝑃𝑃𝑃𝑃𝑃𝑃 + 𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 𝑃𝑃𝑃𝑃𝑃𝑃

30 100

25

25 80

20

20 60

TRIM

15

observed

10 5 0 1960

1970

1980

1990

2000

2010

2020

Flow (m3/s) Flow (m3/s)

Flow (m3/s)

Tukituki at Tapairu Rd 30

Tukituki at at Red Bridge Waipawa RDS w=2

TRIM TRIMobserved observed

15 40 10 20 5 0 1960 0 1960

1970 1970

1980 1980

1990 1990

2000 2000

2010 2010

2020 2020

Max >400 years

Mean 12.5 years

Quick flow Quick flow attenuation /km MODFLOW MRT Slow flow Slow flow attenuation /year

Stream attenuation /km

OVERSEER kgN/y, kgP/y

Tukituki at SH50

Tukituki at SH50

1.2

0.2

SOE

0.6

TRIM

0.4

TP (gP/m3)

0.8

SOE

0.02

TRIM

0.2

1999

2009

2004

0.002 1994

2014

1999

2009

2004

2014

Porangahau at OruawharaRd

Porangahau at OruawharaRd 0.6

10

0.5

6

SOE TRIM

4 2

TP (gP/m3)

8

0.4 SOE

0.3

TRIM

0.2 0.1

0 1994

1999

2004

2009

0 1994

2014

1999

2004

Makaretu at SH50

2009

2014

Makaretu at SH50

2

0.5

SOE

1

TRIM

SOE

0.05

TRIM

0.5 0 1994

1999

2004

2009

0.005 1994

2014

1999

Tukituki at SH2

2009

2014

SOE TRIM

1

1999

2004

2009

2014

TP (gP/m3)

0.15

2

0 1994

2004

Tukituki at SH2

3

TN (gN/m3)

TN (gN/m3)

1.5

TP (gP/m3)

0 1994

TN (gN/m3)

TN (gN/m3)

1

0.1 SOE TRIM

0.05

0 1994

1999

2004

2009

2014

So N and P gets into the river – so what? Aesthetics Mayflies, stoneflies => midges, worms, snails Fish food quality decreases Oxygen and pH problems Fish kills? Toxic algae?

Plant biology 101 Biomass = Growth – Loss Loss = low at low flows Growth = high in summer (temperature, sunlight) Growth = high when N/P supply is high TRIM_STREAM needs to use a DAILY time step but TRIM_CATCHMENT predicts annual N & P inputs

1

1

0.1

0.1

lookup

0.01

Monthly monitoring concentrations lookup

0.01

DRP

DRP 0.001

0.001

0.0001 1/01/1994

0.0001 1

10

100

1000

10

10

1

1

0.1

0.1

1/01/1999

1/01/2004

31/12/2008

lookup TP

0.01 0.001

lookup TP

0.01

Resampled daily concentrations

Current annual load

0.001

0.0001 1

10

100

1000

0.0001 1/01/1994

1/01/1999

1/01/2004

31/12/2008

Future annual load

Future daily concentrations

Increased N/P inputs => higher growth rate High growth rate => biomass accumulates faster between floods => Biomass is high more often => maximum biomass is Higher NB Long periods of low flow => high biomass

even if N/P inputs are low

Calibration January 2011

P controls plant growth and biomass Evidence of P recycling or release

Questions addressed using TRIM_STREAM 1. How far from a source do nutrients elevate biomass? 2. Is N or P the limiting nutrient in the Tukituki?

nutrient

Case 1: no nutrient recycling (Thomann 1970)

periphyton distance

WWTP nutrient

Case 2: nutrient recycling (Chapra pers. comm.)

periphyton distance WWTP

Top reach – P limited Bottom reach – N limited Denitrification? Sediment P release?

Plant growth can’t explain N loss Denitrification? Confirmed by 2012 survey

Observed and predicted time series 16/05/2011

5/02/2011

0 28/10/2010

0.02 35

20/07/2010

prd 74km

11/04/2010

0.03

Biomass (gC/m2)

Tukituki @ Red Bridge

1/01/2010

16/05/2011

5/02/2011

28/10/2010

20/07/2010

11/04/2010

1/01/2010

DRP (g/m3)

0.05 prd 74km

Tukituki @ Red Bridge

0.04 30

25

20

15 10

0.01 5

0

Predicted benefits of reducing P inputs from the WWTP 60

0.1

50

30

28/09/1991

28/09/1991

12/03/1991

0

24/08/1990

0

5/02/1990

10

20/07/1989

0.02

12/03/1991

20

24/08/1990

0.04

40

20/07/1989

0.06

Current

1/01/1989

Biomass (gC/m2)

0.12

0.08

Consent

70

Current

1/01/1989

DRP (g/m3)

Tapairu Rd

Consent

5/02/1990

Tapairu Rd 0.14

Effects of intensification – no P mitigation

TRIM1 study (Rutherford et al. 2011)

Frequency of compliance with guidelines

TRIM1 study (Rutherford et al. 2011)

Problem • High plant biomass in summer low flows is not a new problem in cobble-bed East Coast rivers • Biomass = Growth - Loss • Increasing N/P supply increases growth rate • High biomass occurs more frequently

• Higher maximum biomass occurs • Decreasing flow reduces dilution and loss

Solutions • On-farm N/P loss control/reduction Stock exclusion, Riparian buffers and wetlands, Critical source area control Improved effluent irrigation etc

• Practical methods are available (e.g., AgResearch toolbox) • Adoption is patchy – Cost, Availability of information/technology

• Improved management of wastewater discharges – Cost for small municipalities

• Flushing flows – possible with a dam • Riparian shade – small streams only • No magic bullet • Combinations of measures required

Challenge Agree/implement combinations of mitigation measures so we can have…

…but not this (…too often)