Bathing Water Services Anders Chr. Erichsen

Bathing Water

Services

Operational

Systems

Details of the

approach

Benefits of our

approach

Managing expectations for

Bathing Water Legislative requirements and public perception of bathing waters

have changed. The EU Bathing Water directive has placed

additional requirements on utilities with respect to CSO

discharges.

With the existing pipe networks and increasingly frequent intense

rainfall events, managing CSO discharge in the bathing water

season continues to challenge.

#2

Bathing Water Directive

• ’...The purpose of this [the Bathing Water] Directive is to preserve, protect and improve the quality of the environment and to protect human health ..( article 1, section. 2)’

• ’’…Bathing waters are to be classified as ‘sufficient/good/excellent… if - when subject to short-term pollution - adequate management measures are being taken, including surveillance, early warning systems and monitoring, with a view to preventing bathers’ exposure, by means of a warning or, where necessary, a bathing prohibition (Annex II, sections 2, 3 and 4)

The ongoing problem

Bournemouth, August 2011

Short term pollution (< 72 hours)

• In the UK most short term pollution originates from

direct or indirect (through rivers) outlets from the sewer

system or waste water treatment plants in connection

with rain.

• Problems of diffuse pollution within the catchment are

often longer term

#5

Vibrio

Other

Currents

Waves

Algal

blooms

Indicator

bacteria

safe bathing water 24/7

closing only when necessary

quick information

user-friendly information

Operational Bathing Water Forecasts Copenhagen

© DHI #8

#9

CPH Harbour Copenhagen

Early warning system for Copenhagen harbour

Since year 2002 Copenhagen EPA has used an early warning model for the bathing

water quality in Copenhagen harbour

…but why did Copenhagen introduce an Early warning system before the new directive was agreed

upon? And implemented - 2015?

The traditional monitoring is not sufficient

– Measurement results are received after the incidence is over

– The bathing water maps are based on measurements that are up to one year old

Statistically the traditional monitoring is strong but in practice the beach guests have no guarantees

regarding Today's water quality

Health risk?

Health demands

• Keywords: Secure health

• E.coli and enterococci bacteria

• Heavy metals

• in the water phase

• by re-suspension

• in the sediment

Point Sources (Mapping)

WWTPs

• Two large-scale WWTPs (750.000 and 350.000 PE)

Combined sewer overflows (CSO)

• Both wastewater and urban run-off (“Stormwater”)

Urban run-off

• Separate urban run-off (“Stormwater”)

River with CSO + urban run-off – Sewer installation

Direct industrial discharges to CPH Harbour

#13

Point Sources

#14

Early warning system for Bathing water Quality

Early warning system for bathing water quality

Imagen CSIC 2-8 17:20 Prim Bac de

Roda

Ginebra

Imagen CSIC 2-8 17:20

Resultado simulación 2-8 18:00

Example from Barcelona

10 June, 2014 © DHI #18

Bathing water and the Public

……. And Smart Phones

Auckland Bathing Water Forecast

© DHI

Auckland Bathing Water Forecast

© DHI

Operational Bathing Water Forecasts Example of application

© DHI #23

Extreme Rainfall event in Copenhagen 14. August

Use of Bathing Water forecast – Triathlon 15. August

UTC tid (lokaltid = UTC+2)

Start

kl. 6

Health Risk

1.700 iron men was swimming in sewer

water (Politikken, 20. Aug)

…… a lot of debate, and people getting sick, …

but ……… the Model was spot on

In total 778 (59 %) answered the

questionnaire

send out by the SSI. Out of these

428 (55 %) confirmed symptoms

of gastro-enteritis.

Ref.: SSI

Details of the Approach

10 June, 2014 © DHI #27

Basic Requirements • Local hydrodynamic model (3D) of receiving waters

• Based on wind, air pressure, air temperature provides current, water levels,

water temperature and transport

• Sources of pollution

• Boundary Model (Water forecast)

• Water level, current

• Salinity

• Temperature

• ECO Lab model

• Based on salinity, water temperature and solar radiation (and transparency)

provides bacteria decay

System Components & Functions • Meteorological & model boundary data

• Wind

• Precipitation

• Air temperature

• Clearness

• Humidity

• Water level

• Water temperature

• Salinity

• Current?

• Bacteria (zero?)

• Why?

• Drive the Hydrodynamic model providing

• Circulation,

• Water temperature

• Water levels

• Salinity

System Components & Functions • Direct sources of pollution

• Rain water run-off

• Combined sewer overflows (CSO)

• Waste water treatment plants (WWTP)

• Daily input

• By-pass

• Why

• Important sources for bacteria pollution

(E.coli & Enterococci)

• Origin

• Measurements from WWTP

• Measurements in sewer system

• Sewer modelling/estimations from precipitation

• Estimations from precipitation (modelled, measured, radar)

System Components & Functions • Indirect sources of pollution

• Rivers & estuaries

• Catchment modelling inputs

• Direct sources input to indirect input

• Why?

• Can be equally important

• Origin?

• Estimations from precipitation

(modelled, measured, radar)?

• Additional data

• Direct sources spilling to indirect sources

System Backbone

Internal Surveillance

Internal Surveillance

Internal Surveillance

Internal Surveillance

Handling Flags

QA

Internal QA

10 June, 2014 © DHI #41

Internal QA

Internal QA

Internal QA

Internal QA

Benefits of our Approach

10 June, 2014 © DHI #46

Benefits of our approach

• Warning system for use internally and externally

• Improved public perception of bathing water quality

• Provides added value use of existing telemetered systems

• Can operate outside of traditional bathing water

season for added value

• Extensible and customisable in the future

#47

Thank you for your attention … Anders Chr. Erichsen (aer@dhigroup.com)

© DHI #48