Calculation of water quality targets in the south-western Baltic Sea on the edge of WFD and MSFD

René Friedland T. Neumann, G. Nausch, N. Wasmund,

G. Schernewski (IOW & Klaipeda University)

20.01.2016, Brussels

Coastal waters: national responsibility Water Framework Directive (WFD)

Open sea waters: HELCOM’s responsibility Marine Strategy Framework Directive (MSFD)

State Agencies of

Federal states

German

Environmental Agency

Commonalities

• Aim: Good Ecological State (GES)

• Defined via thresholds (“target values”)

• Based on „reference conditions“

• Nutrient load reductions

as only measure

very good

good

moderate

Reference Value

Target Value

good

bad

Target Value

WFD MSFD

…

Workshop, IOW, Warnemünde, 29.08.2011 (GS) ......Symposium on inshore waters, LUNG Güstrow, 13.09.2012 (GS)

Workshop, LUNG, Güstrow, 14.09.2012 (GS)1. UAG Nährstoffreduktionsziele & Eutrophierung Baltic Sea, BSH, Hamburg, 15.11.2012 (GS)

HELCOM climate change workshop, IOW, 05.02.2013 (GS, RF) 2. UAG Nährstoffreduktionsziele & Eutrophierung Baltic Sea, IOW, 06.02.2013 (GS, RF)

Mini-Symposium "Marine Monitoring", LLUR Flintbek, 19.03.2013 (GS) 3. UAG Nährstoffreduktionsziele & Eutrophierung Baltic Sea, BSH Hamburg, 26.03.2013 (GS) 4. UAG Nährstoffreduktionsziele & Eutrophierung Baltic Sea, LUNG Güstrow, 28.10.2013 (GS, RF)

Symposium on inshore waters, LUNG Güstrow, 20.11.2013 (RF) 5. UAG Nährstoffreduktionsziele & Eutrophierung Baltic Sea, LUNG Güstrow, 13.02.2014 (GS, RF)

Mini-Symposium "Marine Monitoring", LLUR Flintbek, 26.03.2014 (GS) Symposium on marine environment, BSH Hamburg, 03.06.2014 (RF)

AG Nährstoff-Referenz- und Orientierungswerte North Sea, BSH Hamburg, 08.07.2014 (GS) 6. UAG Nährstoffreduktionsziele & Eutrophierung Baltic Sea, BSH Hamburg, 15.09.2014 (RF)

Symposium on inshore waters, LUNG Güstrow, 19.11.2014 (RF) Mini-Symposium "Marine Monitoring", LLUR Flintbek, 05.03.2015 (GS)

Fach-AG „Eutrophierung, Nährstoffe und Plankton“, DWD Hamburg, 14.07.2015 (RF) AG ‚Water quality targets North Sea‘…….

2011

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2012

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2013

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2014

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2015

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Joint BLANO working group with all involved agenciesInformal workshop

Public discussion organized by agencies

Join

t p

roje

ctIn

ad

van

ce o

f a

pro

ject1. Informal workshops

2. Joint working group (with a pre-defined work order by BLANO)

3. Public discussions

4. Joint scientific project (funded by BMBF)

5. Scientific paper (in English)

6. Joint extensive report (in German)

Eutrophication

parameters:

surface

concentrations of

Chlorophyll a,

Total Nitrogen &

Phosphorus

-> Secchi Depth is

missing First assessment (2009):

43 of 44 German water bodies not in GES

Review of present targets:

purely salinity dependent

with one target for every water type

Targets for Chlorophyll:

2 levels

intercalibrated for open coastal waters (GER, DK, PL)

0

50

100

150

200

250

0

5

10

15

20

25

Oder (River) Small Bayof Oder Lagoon

SouthernPomeranian Bight

Arkona Sea(HELCOM)

Target [µmol/l] State [µmol/l]

Total Nitrogen (annual average)

TN & TP targets unreachable (no motivation to start measures)

due to unrealistic ‘pristine’ loads of Oder

Used loads by Brockmann et al. (2012): 3.669 t TN /a (244 t TP/a)

Historical loads from Gadegast et al. (2012): 13.425 t TN/a (950 t TP/a)

Present loads [2000-09]: 55.000 t/a (3.200 t TP/a)

New approach necessary!

Demands:

Reachable & realistic reference conditions and target values

Chlorophyll targets in agreement with intercalibrated values

Singular approach for nutrients, Chlorophyll & Secchi Depth

Harmonized targets for coastal waters and open sea

Natural gradients from emission sources to open sea considered

How to define reference conditions/ values?“high status with no, or very minor disturbance from human activities”

1. Use observations from 1960s

2. Calculations based on

‘pristine conditions’

3. Assume realistic historic situation

(e.g. around 1880) & use an model

to calculate targets

Sparse in space & time

Not consistent with WFD

lack of knowledge and data

high uncertainties

worth pursuing?

Most reliable

Consistent with WFD & MSFD

Model errors to be considered

1880 as reference condition

• We go back as far as possible and reliable

• Land usage documented & comparable with today

• basis for a realistic & reachable ecological state

17% of present loads

22% of present loads

Figures provided by J. Mahnkopf (IGB)

• German loads & Oder from catchment model MONERIS

• Baltic Sea wide load reconstruction from BNI

• Ignore changes in the ecosystem (e.g. macrophytes)

How to deal with the model`s

uncertainty?

Simulated Chlorophyll Present

loads

Historical loads

measure for the specific reaction to the different loads

historical / present simulated chlorophyll

TP (annual)

TN(annual)

Chlorophyll (summer)

Always

steep gradients!

0

0,5

1

1,5

2

2,5

Present State Reference Value Proposed Target Present Target

Ch

loro

ph

yll a

[µ

g/l

]

Station O5

+ 50%(following

WFD guidance)

Multiplication with ratio from

simulation (0.6)

historical / present simulated chlorophyll Fits with intercalibrated target

Natural gradients are reproduced!

intercalibratedtargets

reproduced

new targets reflect local characteristics

stronger

new targets fit with present

ones

0

100

200

Oder (River) Small Bayof Oder Lagoon

SouthernPomeranian Bight

Arkona Sea(HELCOM)

Tota

l Nit

roge

n [

µm

ol/

l] Present target

State

new proposed target

Reachable & realistic

All defined demands fulfilled

Demands:

Reachable & realistic reference conditions and target values

Chlorophyll targets in agreement with intercalibrated values

Singular approach for nutrients, Chlorophyll & Secchi Depth

Harmonized targets for coastal waters and open sea

Natural gradients from emission sources to open sea considered

Reference values fit with historical observations

• Chlorophyll at Kiel Bay from 1905/06

• Secchi Depth at Bay of Greifswald and Small Bay of Szczecin Lagoon

1,28

0,60

2,52

(2,5)

2,632,82

0

1

2

Bay of Greifswald Szczecin Lagoon (Small Bay)

Sum

me

r Se

cch

i De

pth

[m

]

present state historical value (from literature) integrated model

Review of ecological state & targets

Modifying targetsImplementation

of measures

• Statistical attempt to link loads (TN & TN/TP-ratio) to CHL.a(averaged for the south-western BS, including parts of DK & PL)

• Result: TN-load reduction of 34% necessary (to decrease Chlorophyll-conc. by 20%)

• Assuming full implementation of Gothenburg Protocol

Total N [t/a]Atmospheric

TN [t/a]Waterborne

TN [t/a]River conc.TN [mg/l]

Total P [t/a]

Chl.a[µg/l]

1997-2003 (PLC 5.5)

32.697 13.007 19.690 4,7 526 4,5

Allowable German Loads

21.477 10.406 11.072 2,6 526 3,6

New proposed target for German river loads

BSAP (2013) 29.640 11.900 17.740 4,3 356 4,2

TN-load reduction of BSAP not sufficient for coastal waters!

Target: river loads

Good ecological state of the Baltic Sea

Management: catchment area

Target: inner coastal waters

Target: outer coastal waters

German environmental agencies

Research Institutes

René Friedland (IOW), G. Schernewski (IOW & KU), G. Nausch, T. Neumann, N. Wasmund (IOW),

W. Leujak (UBA), T. Petenati (LLUR), M. v. Weber (LUNG), M. Venohr, M. Gadegast, J. Mahnkopf (IGB)

Supercomputing power was provided by North-German Supercomputing Alliance:

Work was financed by: