Bathing water profile: The Dutch approach and practical cases. Hans Ruiter Imke Leenen (Grontmij)

Bathing water profile: The Dutch approach and practical cases Hans Ruiter Imke Leenen (Grontmij)

30 september 2009

Netherlands 650 bathing water sites • 570 inland water • 80 coastals

Ministerie van Verkeer en Waterstaat 2

30 september 2009

Introduction Bathing water management by several agencies: • Water boards are responsible for water quality • Provinces responsible for public info • beach management divers per location Bathing water profiles should be easy to interpret for all these agencies Coastal health issues are mainly of fecal origin in the Netherlands. This presentation focuses on this aspect


30 september 2009

Bathing water profile:what should it bring? • understanding of water system at a bathing site • Understand which fecal sources are important for the bathing water quality – – – – –

To protect bathers To adequately inform the public To apply to the bathing water directive To support management actions Tool to communicate between agencies


30 september 2009

Bathing water profile: the Dutch approach Should be: • Practical • Cost-efficient • Independent • Relatively simple • Applicable for all locations Consequences: • As much as possible use of available data • Usage of guide values for fecal sources Approach made by and with government, provinces, water boards and bathing water experts National guidance Ministerie van Verkeer en Waterstaat 5

30 september 2009

Roadmap


30 september 2009

Approach: sources identification Local description and hydro morphology: - Map of location and surroundings - Description of usage - Hydrological situation - Location size - Area of influence: dependent on local situation - Bathing zone define bounderies - ….


30 september 2009

Bounderies • Protocol sea water • Why boundaries: – To calculate/analyse influence of sources on the water quality Ma in this zone as 8

vla kte

10 0

Ge m

10 6

De n

11 2

Ha ag

Ki jk

Sc he ve nin ge

aa lS

7 Oo stv oo rne

n

ch ev en ing en

cka Ro

nje

du in

13 M on ste Vl rot wa Te te rh rin eij de g

H Ho oek lla va nd n


30 september 2009

Visit to location Check on: • Hydrological and local situation • Practical human usage of location • Beach management (on dogs, birds, horses, hygiene..) • Independent expert view of bathing site • Identify and estimate size of unknown sources Important: • In bathing season • Feed back of bathers • ‘open view’


30 september 2009

Historical data • Use of bathing water data of the last five years • To detect typical patterns in parameter values • To analyse relations of parameter values with: – Rain fall – Temperature (water and atmosphere) – Windspeed and direction – Tide or current – Season – Sun hours – …


30 september 2009

Result • List of local sources


30 september 2009

Quick-scan:Analysis influence of sources Usage of guidance values to: • Minimise investment in analysing the polluting effect of each source • Identify most important local source(s) • help (local) authorities to focus on most important source(s) Information needed: - Area of water - Length of bathing zone - Sources to take into account and their distances - … Result: first impression of important source(s). That’s it! Ministerie van Verkeer en Waterstaat 12

30 september 2009

Evaluation/results • Impression/learnings from steps before in correspondence with quick-scan? • Identify uncertainties • If source(s) are identified which have an impact on the water quality: – Advice for monitoring/analysing specific sources – Advice of reducing pollution by management actions – Advice to remove source(s) Update bathing water profile after actions are taken.


30 september 2009

Where are we now?...Realization • 80% locations ready • Costs per beach divers between €5.000 and €10.000,-

This is our approach and it works for the Netherlands What does it bring in practice?


30 september 2009

Practical cases/experiences Field visit – what is found? • Changes in hydrological situation – Extra opening to water – Streams closed or diverted • Bathers, visitors – Usage of location – Extra beach or longer/shorter zones – Usefull information by interviews/talks • Maps out of date • Water birds, dogs, horses – Investigation of imprints – Bathres gone, horses in water – Dog beaches Ministerie van Verkeer en Waterstaat 15

30 september 2009

What do you find? • • • • • • • • • • • • •

Overflow in hinterland Bathers Birds Dogs Horses Rain water flows onto beach and water Boats (recreational and business) Cattle nearby or in hinterland Sewerage plant Farms Leaking pipes Harbours etc….


30 september 2009

Examples


30 september 2009

Examples


30 september 2009

Sample location for monitoring • Not always where the bathers are • Not always ot correct spot • Ask samplers to monitor also: – Amount of birds – Amount of bathers – Amount of horses – Changes in local situation


30 september 2009

Historic water quality (1)

Neerslagintensiteit en hoeveelheid en thermotolerante bacteriën van de coligroep 2004 Neerslagintensiteit

Neerslag hoeveelheid

data

Norm

20

• Relation with season

2500 15 2000 10

1500 1000

5 500 0

Thermotolerante bacteriën van de coligroep (kve/100 ml)

Neerslagintensiteit (mm/h) en neerslag hoeveelheid (mm)

• Relation with rain fall

3000

0 apr

mei

jun

jul

aug

sep

Jaartrends van thermotolerante bacteriën van de coligroep 2001

2002

2003

2004

2005

2006

extreme 2006

Norm

Thermotolerante bacteriën van de coligroep (kve/100ml)

3000 2500 2000 1500 1000 500 0 apr

mei

jun

jul

aug

sep


30 september 2009

Historic water quality (2)

Zonne-uren en thermotolerante bacteriën van de coligroep 2004 3

2

1

data

Norm

• Relation with sun hours

Zonne-uren (uren)

14

2500

12 2000

10

1500

8 6

1000

4 500

2 6-sep

31-aug

23-aug

16-aug

9-aug

3-aug

26-jul

20-jul

12-jul

6-jul

21-jun

8-jun

24-mei

19-apr

• Relation with wind

0 10-mei

0

Thermotolerante bacteriën van de coligroep (kve/100 ml)

3000

16

Fecale streptococcen en windrichting en -snelheid, 2003 meetgegevens

norm

450 350 250

1.8

150 50 -450

-250

-50 -50

2 3 2.1 3 2.3 6 1.5 2.9 .5 4.7 3.6 150

350

-150 -250 -350 -450


30 september 2009

Quick-scan model (ZWEMPROF) legenda EC Geen invloed op zwemwaterkwaliteit (E.c <200KVE/100ml) Geringe invloed op de zwemwaterkwaliteit (E.c tussen 200 en 500KVE/100ml) Wezenlijk invloed; gemiddelde onder de norm, maar incidenteel overschrijdingen te verwachten (E.c tussen 500 en 900KVE/100ml)

Bijdrage bronnen Naam locatie: Zwanenwater Datum beoordeling: 39055

Grote invloed bron: maatregelen noodzakelijk (E.c >900KVE/100ml) legenda IC Geen invloed op zwemwaterkwaliteit (IE <100KVE/100ml) Geringe invloed op de zwemwaterkwaliteit (IE tussen 100 en 200KVE/100ml) Wezenlijk invloed; gemiddelde onder de norm, maar incidenteel overschrijdingen te verwachten (IE tussen 200 en 330KVE/100ml) Grote invloed bron: maatregelen noodzakelijk (IE >330KVE/100ml) gemiddeld EC

Zwemmers Recreatievaart RWZI Agrarisch achterland RioolOverstort gemengd stelsel gescheiden stelsel Lozingen slachthuis of mestverwerkend bedrijf Ongezuiverde lozingen Afstromend wegwater Beroepsvaart Jachthavens Watervogels Lokale bron (Incidenteel) Lokale bron (continue belasting)

zeer druk EC

gemiddeld IE

zeer druk IE

eindoordeel EC gemiddeld

eindoordeel EC zeer druk

eindscore IC gemiddeld

eindscore IC zeer druk


30 september 2009


Bijdrage bronnen Naam locatie: Oud Valkeveen Datum beoordeling:


Zwemmers Recreatievaart RWZI Agrarisch achterland (konijnen) Agrarisch achterland (koeien) RioolOverstort gemengd stelsel gescheiden stelsel Lozingen slachthuis of mestverwerkend bedrijf Ongezuiverde lozingen Afstromend wegwater Beroepsvaart Jachthavens Watervogels Lokale bron (Incidenteel) Lokale bron (continue belasting)

zeer druk EC

gemiddeld IE

zeer druk IE






30 september 2009


Bijdrage bronnen Naam locatie: Veluwestrand Datum beoordeling:


Zwemmers Recreatievaart RWZI Agrarisch achterland RioolOverstort gemengd stelsel gescheiden stelsel Lozingen slachthuis of mestverwerkend bedrijf Ongezuiverde lozingen Afstromend wegwater Beroepsvaart Jachthavens Watervogels Lokale bron (Incidenteel) Lokale bron (continue belasting)

zeer druk EC

gemiddeld IE

zeer druk IE






30 september 2009

Short changes in quality • • • • •

Sewerage overflows Stormwater run off Rain water overflow Seasonal bird visit Tide

• Relation found with climatological data? • Advice to confirm with sampling


30 september 2009

Advice on management actions • • •

• • • • • • • • •

Changes in overflows Setting boundaries for cattle Informer public – Effect dogs/horses – Effect hygiene Place special dog beaches (below stream) Placement of toilets Dilute Changes in location of pipes or connecting streams Deepen location Bathing zone or beach change to better location Make it difficult for birds Accept sometimes bad quailty Monitoring - knowledge on sources


30 september 2009

What does our approach bring? • Insight in a local situation • Independent view of the location • A concrete rapport to start discussion between all partners • The information needed to communicate with and inform the bathers and visitors


30 september 2009

What comes after a bathing water profile? • Water quality excellent or good: bathing water profile is ready. • Water quality acceptable or poor or risk of pollution is high: bathing water profile is ready, but management actions must be taken such as: – Close beach – Research programm on the main source of pollution • If relevant: reduce influence – Inform public – Etc. After this bathing water profile must be updated.


30 september 2009

A practical example: after the bathing water profile Bathing water profile gives high risk of pollution if pumping station is pumping in summer – No influence: bathers, dogs, birds, horses, boats, Noordsea canal, nearby cities – some influence: sewage plants Houtrust en Harnschpolder – Important influence: Pumping station Katwijk: • capacity 54 m3/s • At 100 meter from beaches • Influence area some kilometers along the coast • Historical data: relation with pumping

What is the situation? Ministerie van Verkeer en Waterstaat 29

30 september 2009

Spaarndam: 34 m3/s Halfweg: 34 m3/s

Katwijk: 54 m3/s (future 96 m3/s)

Bodegraven: 1 m3/s to 25 m3/s

30

Gouda: 40 m3/s

Ministerie van Verkeer en Waterstaat 30 september 2009

Research programm and system analysis • 2005 en 2006 extended monitoring • Sources fecal pollution hinterland monitored • 31 sample locations surface water – Overflow locations – Locations of effluent sewage treatment plants – Boundaries of area under research • System analysis 2007 data • Hydrodynamic model waterboard • Sewaragemodels cities


30 september 2009

Overflows

beach


30 september 2009

Sewage plants


30 september 2009

Results system analysis • No conclusive image of ‘main source’ • Pumping is important: – Short pumping: Large overflows nearby important source – Little rainfall: sewage treatment plants contribute a lot to pollution – Heavy rainfall: overflows high contribution – Pumping at full capacity: within 24 hours all sources arrive at beach


30 september 2009

How can we reach good bathing water quality here • • • • • •

Extra purification step at sewage treatment plant Delay the polluted water Try to move water to other pumping station Dam into the sea (large pipe) Change overflows Etc

• But none of these actions is enough. Investigation is still going on.


30 september 2009

Bathing water profile: The Dutch approach and practical cases. Hans Ruiter Imke Leenen (Grontmij)

Recommend Documents