Stormwater Harvesting and Reuse...to dream the impossible dream ?

Ted Gardner and Rezaul Chowdhury

Urban Water Security Research Alliance

Stormwater Harvesting and Reuse Project18 August 2009

Co Investigators

• Graham Jenkins• Margaret Greenway• Fran Sheldon• Carolyn Polson• Oswald Marinoni• Luis Laredo• Jason Dunlop• Richard Gardiner

TALK OUTLINE

• History• Some success stories• Harvesting Opportunities• Water Quality• Hydrology-ecosystem health

Stormwater end uses in Australia

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NSW VIC SA WA QLD

public open spaceirrigationgolf course irrigation

dual reticulation

other

n = 61

PhilpPhilp et al 2009et al 2009

The Seductive Appeal of Stormwater

The Seductive Appeal of Stormwater

Water UseGL/yr

Stormwater Discharge GL/yr

Sydney 530 400

Melbourne 440 300

SEQ 480 500

Perth 425 200Kenway et al. 2008

Fundamental Challenges for Stormwater Reuse

• CAPTURE

• TREATMENT

• STORAGE

• DISTRIBUTION

Key challenges

Some Stormwater Reuse Success Stories

• Parafield South….. Adelaide• ASTR….. Adelaide• Marina Barrage…. Singapore• Southbank …..Brisbane• Orange……NSW• Pacific Pines….. Gold Coast

The Parafield Stormwater Site

Schematic of Parafield Ponds and Pipes

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In-stream basin47 ML

Holding storage48 ML

PS 1 - 2 x 25 ML/d1 x 3.5 ML/d

Cleansing reedbed2.0 ha

Michell

pipeline

225 –

300 m

mData station

PS 2 - 2 x 3.25 ML/d VSD

Diversion weir

ASR T2 aquifer 2 x 4.3 ML/d VSD pumps

450 mm300 mm

Parafie

ld drain

N-S R

ailway

300m

m

Site control

Pressure monitor

To MawsonLakes

To Michell Australia

225 m

m

Stormwater diversion weir at Parafield

Stormwater diversion weir at Parafield

Reed bed to reduce contaminants

Injection bore for surplus stormwater

Injection bore for surplus stormwater

END USES• MAWSON Lakes non potable reuse• Michele Wool Scour• Supplies about 1,000 ML/yr

The ASTR project…turning stormwater into potable water

P.Dillon 2009

Marina Barrage

The Marina Barrage lagoon is 240 hectaresThe Marina Barrage lagoon is 240 hectares

The Barrage drains 10,000 hectares = 1/6 Singapore

Supplies 40 GL / year of potable water = 12% of total water demand

sea

Marina Barrage visitors centre and pump station

http://www.sydney-australia.biz/maps/nsw/map-nsw-australia.php

Pump station at holding pond

200 mL holding pond

2 x 17 ML batch treatment ponds

First flows into Suma Park dam

Note low level

PROJECT OBJECTIVES

• GIS analysis of storage & reuse opportunities

• Measurement ( & modelling) of stormwater quality

• Hydrology,stormwater harvesting & creek ecosystem health

GIS analysis of storage & reuse options

• Greenfield urban footprint• Aquifers, ponds, quarry voids• Topography (DEM analysis)• End use 70 kL/hh/yr potable

substitution rule • Bleeding into sewers PRW• Exemplar typologies in new urban areas

SEQ needs 754,000 new homes by 2031SEQ needs 754,000 new homes by 2031

Ipswich has the highest predicted growth

ASR Potential of the Tertiary

Aquifer - Brisbane

SKM & CSIRO 2009

Enoggera Dam

The Gap

Enoggera Reservoir

200 ML Stapylton Storage (Quarry Void)

GIS map of SEQ urban catchment

How to incorporate Stormwater harvesting & reuse into the Urban Fabric?

Frequent flow management to capture:• 15 mm of runoff when

impervious surfaces are greater than 40%

Water stability management• Reduce peak flow for the 1

year ARI to pre-development peak flow

SEQ Regional Plan Guideline # 7

QWC consultancy..2009

• Case studies for integrating stormwater reuse into new subdivisions with mandated WSUD features.– Bligh Tanner P/L + Design Flow P/L– 2 catchment types – North Lakes and Sippy

Downs– Range of slopes, scales (10 ha 500 ha)

housing densities, residential / commercial / industrial mixture and storage volumes.

• 6 scenarios explored for each development : Traditional WSUD

WSUD + SWH (internal & external end uses)

• Used MUSIC & SWWM models• Different dwelling densities… 11 - 100/ha• Detailed costing & yields…. ML/ha/year.

QWC consultancy..cont.

North LakesNorth Lakes

• 7000+ lots with approximately 4000 complete

• Undulating medium slopes (5 to 10%)

• Can explore 10ha, 100ha & 500ha options

Sippy Downs

• High Density• Mixture of residential &

commercial• Flat to medium slopes (2 to

5 %)• Small area (26ha) but

dense….12,000 EP• Reproducible precinct scale

Results from Bligh Tanner Study

• Need high urban density or an external customer to maximise yield and minimize $/ML cost.

• Minimum acceptable scale 20 ha …..100+ha is better

• 2 – 10% undulating slopes allows precinct scale storages and hence reduce costs

• < 2% - will require multiple storage locations per catchment

• Land for storage expensive – aquifer storage most cost effective by far.

Results from Bligh Tanner Study

• At large scale (> 10,000 dwellings) - distribution costs dominate

• At small scale (100 – 1000 dwellings) – treatment costs dominate

• Levelized cost for harvested stormwater - $3,000 – $5,000 / ML – cheaper than rainwater tanks.

Stormwater Quality

• Non Potable issues:-– sediment– pathogens

• Potable issues:-– sediment– pathogens– heavy metals– trace organics

Lack of information on pathogens in Australian urban stormwater is a

generic weakness of these guidelines.

Pathogens of Interest• Protozoa 4 – 20 um

– Most harmless– Pathogenic examples

• Cryptosporidium, Giardia, Amoeba

• Bacteria 1 – 4 um– Most harmless and beneficial– Pathogenic examples

• Shigella, Vibrio cholerae, Pseudomonas • Mycobacterium tuberculosis

• Viruses 0.02 - 0.475 um– All human viruses are potential pathogens– HIV, Polio, Adenovirus, Rotavirus etc.

X 1,000

X 1,000

X 10,000

Courtesy Dr Helen Stratton

Direct monitoring of pathogens using PCR

• PCR can be used for direct monitoring of specific pathogens

• Detect pathogens that are difficult to grow• Rapid (i.e., results can be obtained in 6

hours)• Sensitive

Quantitative PCR

• Quantitative PCR also called real-time PCR

• Detection and quantification of a fluorescent reporter which increases in direct proportion to the amount of PCR product in a reaction

Possible Trace Chemicals in Stormwater

• Heavy Metals• Sterols• DBPs• Pesticides• PAH• Phenols• Ethoxylates• ….and other trace organics

ISCO automatic water sampler

V notch weir in stormwater culvert

V notch weir in stormwater culvert

Typical shed and community sign

Data logger

RF receiver

Solar regulator

Collecting water samples

Event based sampling is experimentally complex

Samping Program Bioretention Inlet 17 and 18 April 2008

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Bottle 24 (last bottle inautomatic sampler)First flush

Sampling program required to capture data during sporadic rainfall events

Capturing consecutive rain events

Event based monitoring produces a lot of samples!!

….and chemical analyses is expensive

cost per sample• Organics (limited suite) $560

Inorganics (heavy metals etc.) $170

qPCR microbiology $475Protozoan culture array $445

$1650 per sample• 10 samples per storm event $16,500 per event• Full AZ of chemicals as per ASTR project

~ $5,000 per sample

So before we start….

• Need to understand the scope of the problem

• Explore modelling options•

Commissioned literature review from

Griffith University

Stream Ecosystem Health

& Stormwater Harvesting

Impacts associated with conventional approaches to urban stormwater management

–Water quality; physical and chemical toxicants –Biological condition; shifts in community composition –Hydrology; inc frequency of small events and magnitude

of peak flows –Geomorphology; erosion, habitat loss, bed/bank stability

Streambank erosion following urbanisation

Streambank erosion following urbanisation

Sediment fan downstream of an SEQ subdivision

Ecosystem health and directly connected impervious area

Chris Walsh 2006

Scientific studies of the waterway catchments of South East Queensland (SEQ) have linked urban stormwater with impaired ecological condition of local waterways and the Moreton Bay Marine Park (Healthy Waterways, 2006)

Catchment Scale Experiment

• 12 catchments in SEQ• 3 land uses• Measure directly connected impervious

areas• Calibrate hydrology models• Ecosystem health & channel form

Pimpama River, Kingsholme (Reference site)

Indicators: ecosystem structure–Macroinvertebrates

• Number of macroinvertebrate taxa

• PET richness, stonefly, mayfly caddisfly

• Average SIGNAL score

Some Preliminary Hydrology Analysis Sheepstation Creek (Urban)

Cross Section

Cross Section(Sheepstation Creek)

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Distance (m)

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Rating Curve

Rainfall Runoff Model Calibration

SIMHYD

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ObservedSimHyd

SACREMENTO

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ObservedAWBM

Evaluation of Daily Time Step Models

Parameter Observed SIMHYD S’MENTO AWBM

Mean 2.09 2.48 1.64 2.27

St Deviation 8.26 13.09 9.92 9.62

Skewness 6.22 8.28 9.82 6.49

Kurtosis 45.82 76.93 102.84 49.11

10 Percentile 0 0 0 0

90 Percentile 3.06 1.61 1.24 3.18

Nash-Sutcliffe E 0.51 0.70 0.94

“Essentially, all models are wrong, but some are

useful”.

George Box, industrial statistician 1987.

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TotalRunoff

Freq.Surface Runoff

time no.events

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time no.events

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Q1 year Q1.5years

Q5years

Integerof flow

TSS TN TP

Runoff Low flows High flows Peak flows Pollutant loads

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Melbourne Developed

Melbourne Harvesting

Brisbane Developed

Brisbane Harvesting

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MUSIC simulations of hydrology & water quality responses to urbanisation (70% impervious area) with & without stormwater harvesting…..

Tim Fletcher et al 2007

Virtual Stormwater harvesting to recreate pre development flows

Conclusions • Stormwater is the last major untapped source of

alternative urban water supply.• If stormwater is to be “mainstreamed” in SEQ it

must be incorporated into the urban water cycle i.e. potable substitution.

• The Bligh Tanner report has created some insightful exemplar typologies that can be used (with other biophysical data) in GIS analysis for locating future harvest and reuse areas.

• Issues of water quality are important for potable water substitution – they become critically important if potable reuse is considered.

Conclusions …. continued

• Stormwater harvesting, WSUD and creek ecosystem health are intimately related. Our hydro-ecology study should provide local rules for water harvesting operations.

• However calibrated hydrology models at short time steps (< 60 mins) for 200 ha+ catchments will prove a challenge.

Aspirational goal

• Partner a large local stormwater project funded under the $200M Stormwater Harvesting and Reuse Initiative “National Urban Water and Desalination Plan”.

Thank you

www.urbanwateralliance.org.au