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APPENDIX A PUBLICATIONS

1. Evaluating pollutant concentrations and flow rates To evaluate the performance of pollutant concentrations use Statistics and then choose from the desired statistic eg Daily Maximum Flow Weighted Mean All Data etc The approach for evaluating flow rates is exactly the same as for concentrations except that it is the flow rather than TSS TP or TN that is selected for which the statistics are to be presented All Data Statistics x Flow cubic metres sec TSS Concentration mg L Inflows Quttlow Flow weighted Daily Mean Log TSS mg L Ries EE ps p Daily Maxima TP Concentration mg L median ES gt 0 00 Daily Sample C Log TP mg L maximum 2 38 0528 All Data TN Concentration mg L lat gr 0 00 10 percentile 51 8E 6 0 00 Flow Based Sub Sample Log TN mg L 90 percentile ps 5163 Mean Annual Loads TSS Load kg 6 Minutes Treatment Train Effectiveness C TP Load kg 6 Minutes a TN Load kg 6 Minutes Gross Pollutant Load kg 6 Minutes See Chapter 4 of the MUSIC manual for further guidance including information on excluding zero flow periods from the statistics so that the mean value is not distorted by many timesteps with zero flow and thus zero concentration The Cumulative Frequency Graph can also be used to investigate the probability of exceeding a given pollutant concentration or flow rate again this would normally be done fo
2. FAWB Facility for Advancing Water Biofiltration POC It is important that the model accurately represents the system as it is proposed to be built For example the seepage rate should be ideally based on a test of the hydraulic conductivity of the underlying soils or at least on a conservative estimate Evaluating pollutant loads Evaluating the pollutant load reduction performance of a biofilter is easy in MUSIC by simply right clicking on the biofiltration node and choosing Statistics Mean Annual Loads In the case where the performance of several biofilters either in parallel or in series within a catchment is being evaluated use Statistics Treatment Train Effectiveness SE MUSIC Model for Urban Stormwater Improvement Conceptualisation Evapo examp SE File Edit Catchment Tools Window Help RAIN Source Nodes Treatment Nodes Other Nodes Roof are xj Sources Residual Load 7 Reduction Flow ML yr 291 283 25 plus oe ey Total Suspended Solids kg yr 45 1E3 10 863 76 1 T ei tos LESE Total Phosphorus kg yr ho Hear fara Eiofit ion system Total Suspended Solids kav 22 foss 96 2 sia d EE ON i Total Phosphorus kg yr 46 063 6283 365 Total Nitrogen kg yr 761 581 23 6 Total Nitrogen kg yr jase Moro gt Gross Pollutants kay 1 2 8E3 0 00 1 00 0 Gross Pollutants kg yr Bs 000 100 0 al
3. 2005 Nitrogen composition in urban runoff implications for stormwater management Water Research 39 10 1982 1989 FAWB DDC Fy Annen APPENDIX G PRACTICE NOTE 3 PERFORMANCE ASSESSMENT OF BIOFILTRATION SYSTEMS USING SIMULATED RAIN EVENTS FAWB der la SELLER mme CONDITION ASSESSMENT AND PERFORMANCE EVALUATION OF BIOFILTRATION SYSTEMS PRACTICE NOTE 3 Performance Assessment of Biofiltration Systems using Simulated Rain Events Belinda Hatt March 2009 The Facility for Advancing Water Biofiltration FAWB aims to deliver its research findings in a variety of forms in order to facilitate widespread and successful implementation of biofiltration technologies This Practice Note for Performance Assessment of Biofiltration Systems using Simulated Rain Events is part of a series of Practice Notes being developed to assist practitioners with the assessment of construction and operation of biofiltration systems Disclaimer Information contained in this Practice Note is believed to be correct at the time of publication however neither the Facility for Advancing Water Bioifltration nor its industry partners accept liability for any loss or damage resulting from its use 1 SCOPE OF THE DOCUMENT This Practice Note for Performance Assessment of Biofiltration Systems using Simulated Rain Events is designed to provide practitioners with a hydrologic and treatment performance assessment tool where a more detailed assessment than collecti
4. also be considered The following water quality parameters might also be required Con 2 4 The FAWB gt f al ity for Advance ing Water Biofiltration Nutrient species ammonium NH oxidised nitrogen NO organic nitrogen ON and orthophosphate PO commonly referred to as dissolved reactive phosphorus FRP and Other metals aluminium Al chromium Cr iron Fe manganese Mn and nickel Ni sult with the analytical laboratory as to the sample volume required to carry out the analyses Apparatus following is required Semi synthetic stormwater volume as determined in Section 2 1 and prepared according to Practice Note 2 Preparation of Semi Synthetic Stormwater available at www monash edu au fawb products index html Note This will most likely need to be prepared on site Stirrer Means of delivering the water e g tanker truck Tank with removable lid and off take point with tap at bottom of tank Stopwatch x 2 10 L bucket x 2 Scales battery operated capacity to weigh 5 kg precision to 2 decimal places water resistant Water quality sample bottles as required see Table 1 0 45 um quick fit filters allow at least two filters per sample 2x 25 mL syringes Gloves 2 x permanent marker pens Rubber boots Cool box and ice Portable computer and long life battery or several standard batteries Table 1 Handling and preservation procedures for typical water quali
5. n Z O D un Z O 4 Submerged zone Section 1 Maintenance Required Maintenance Performed Yes Yes Weir up turned pipe CIRCLE full blockage partial blockage damage Water level CIRCLE at design level drawn down SOME DRAWDOWN DURING DRY PERIODS IS EXPECTED pee O ae O 5 Additional Comments Biofiltration System Maintenance Plan EXAMPLE 10 FAWB Facility for Advancing Water Biofiltration 5 REFERENCES FAWB 2009 Guidelines for Filter Media in Biofiltration Systems Version 3 01 Facility for Advancing Water Biofiltration available at http www monash edu au fawb publications Biofiltration System Maintenance Plan EXAMPLE 11 FAWB Y9 LCCC M Annen APPENDIX E PRACTICE NOTE 1 IN SITU MONITORING OF HYDRAULIC CONDUCTIVITY FAWB der la PAPER mme CONDITION ASSESSMENT AND PERFORMANCE EVALUATION OF BIOFILTRATION SYSTEMS PRACTICE NOTE 1 n Situ Measurement of Hydraulic Conductivity Belinda Hatt Sebastien Le Coustumer June 2009 The Facility for Advancing Water Biofiltration FAWB aims to deliver its research findings in a variety of forms in order to facilitate widespread and successful implementation of biofiltration technologies This Practice Note for In Situ Measurement of Hydraulic Conductivity is the first in a series of Practice Notes being developed to assist practitioners with the assessment of construction and operation of biofiltration systems Disclaimer In
6. performance of biofilter systems for stormwater management influences of design and operation Journal of Hydrology Le Coustumer S T D Fletcher A Deletic and M Potter 2008 Hydraulic performance of biofilter systems for stormwater management lessons from a field study Facility for Advancing Water Biofiltration and Melbourne Water Corporation Healthy Bays and Waterways Le Coustumer S and S Barraud 2007 Long term hydraulic and pollution retention performance of infiltration systems Water Science and Technology 55 4 235 243 Le Coustumer S T D Fletcher A Deletic and S Barraud 2007 Hydraulic performance of biofilters first lessons from both laboratory and field studies Novatech 2007 6th International Conference on Sustainable Techniques and Strategies in Urban Water Management Lyon France Le Coustumer S T D Fletcher A Deletic and S Barraud 2007 Hydraulic performance of biofilters for stormwater management first lessons from both laboratory and field studies Water Science and Technology 56 10 93 100 Field Studies Hatt B E T D Fletcher and A Deletic 2009 Hydrologic and pollutant removal performance of stormwater biofiltration systems at the field scale Journal of Hydrology 365 3 4 310 321 Hatt B E T D Fletcher and A Deletic 2009 Pollutant removal performance of field scale biofiltration systems Water Science amp Technology 59 8 1567 1576 FAWB gt F
7. to enable effective post treatment disinfection and where minimising the risk of washout during the establishment period is of particular importance The transition layer can be omitted from a biofiltration system provided the filter media and drainage layer meet the following criteria as defined by the Victorian Roads Drainage of Subsurface Water from Roads Technical Bulletin No 32 VicRoads 2004 Dis drainage layer lt 5 x Das filter media D s drainage layer 5 to 20 x D filter media Dso drainage layer lt 25 x Ds filter media Deo drainage layer lt 20 x Dy drainage layer These comparisons are best made by plotting the particle size distributions for the filter media and gravel on the same soil grading graphs and extracting the relevant diameters Water by Design 2009 5 DRAINAGE LAYER The drainage layer collects treated water at the bottom of the system and converys it to the underdrain pipes Drainage layer material is to be clean fine gravel such as a 2 5 mm washed screenings Bridging criteria should be applied to avoid migration of the transition layer into the drainage layer Water by Design 2009 VicRoads 2004 D s drainage layer lt 5 x Dg transition layer where D s drainage layer is the 15 percentile particle size in the drainage layer material i e 15 of the gravel is smaller than D mm and Des transition layer is the 85 percentile particle size in the transition la
8. Additional Comments section at the end of this document 1 Filter media In addition to regular inspections it is recommended that inspection for damage and blockage is made after Sectiont Section2 significant rainfall events that might occur once or twice a year Maintenance Required Maintenance Performed a o Filter media CIRCLE pooling water accumulation of silt amp clay layer scour holes sediment build up Litter CIRCLE large debris accumulated vegetation anthropogenic te 2 Vegetation Vegetation health CIRCLE signs of disease pests poor growth Vegetation densities CIRCLE low densities infill planting required Build up of organic matter leaf litter CIRCLE requires removal ODO ODO Weeds CIRCLE isolated plants infestation SPECIES RL Biofiltration System Maintenance Plan EXAMPLE 9 FAWB gt Facility for Advancing Water Biofiltration 3 Pits pipes and inflow areas Section 1 Maintenance Required Maintenance Performed Perforated pipes CIRCLE full blockage partial blockage damage Inflow areas CIRCLE scour excessive sediment deposition litter blockage Overflow grates CIRCLE damage scour blockage Pits CIRCLE poor general integrity sediment build up litter blockage Other stormwater pipes and junction pits CIRCLE poor general integrity sediment build up litter blockage MD
9. Rain garden The design and thus modelling of treatment systems for reducing runoff frequency will be somewhat different to that for simply reducing pollutant loads Systems which promote infiltration and stormwater harvesting with regular demands eg toilet flushing etc will be most effective For example one solution subject to appropriate distances to infrastructure is to construct a biofiltration system with an unlined base and the underdrain raised above the base to allow water from small rainfall events to infiltrate to surrounding soils see left hand side diagram below with highlighted seepage loss and depth below underdrain parameters Another option is to use no underdrain at all having only an overflow pipe in this case right hand size diagram it can be modelled with a simple infiltration system node in MUSIC The only trick here is to model the extended detention depth as Extended detention depth ponding depth infiltration depth x porosity For a sandy loam system to support plants the porosity 0 4 Therefore in example below if the ponding depth was 0 3m and the filter medium was 0 6m deep the depth to overflow would be 0 3 0 6 x 0 4 0 54 m highlighted below x Locati Biofitration rain garde En 2 1 Properties of Infiltration System 4 x Inlet Properties Low Flow By Pass cubic metres per sec 0 000 Location Infiltration System High Flow By pass cubic m
10. and 2 in the second year of operation to assess the impact of vegetation on hydraulic conductivity The hydraulic conductivity of the filter media should be checked at a minimum of three points within the system The single ring constant head infiltration test method shallow test as described by Le Coustumer et al 2007 should be used Given the inherent variability in hydraulic conductivity testing and the heterogeneity of the filter media the laboratory and field results are considered comparable if they are within 50 of each other However even if they differ by more than 50 the system will still function if both the field and laboratory results are within the relevant recommended range of hydraulic conductivities REFERENCES ASTM International 2006 ASTM F 1815 06 Standard test methods for saturated hydraulic conductivity water retention porosity and bulk density of putting green and sports turf root zones West Conshohocken U S A Bratieres K T D Fletcher and A Deletic 2009 The advantages and disadvantages of a sand based biofilter medium results of a new laboratory trial 6th International Water Sensitive Urban Design Conference and Hydropolis 3 Perth Australia Hatt B E T D Fletcher and A Deletic 2009 Hydrologic and pollutant removal performance of stormwater biofiltration systems at the field scale Journal of Hydrology 365 3 4 310 321 Le Coustumer S T D Fletcher A Deletic and S Barra
11. be higher in order to achieve the required treatment performance using the same land space i e ensuring that the proportion of water treated through the media meets requirements Where one of these design elements falls outside the recommended range the infiltration capacity can still be maintained by offsetting another of the design elements For example a filter media with a lower hydraulic conductivity may be used but the surface area or the extended detention depth would need to be increased in order to maintain the treatment capacity Similarly if the available land were the limiting design element the system could still treat the same size storm if a filter media with a higher hydraulic conductivity were installed Where a hydraulic conductivity greater than 300 mm hr is prescribed potential issues such as higher watering requirements during the establishment should be considered Biofiltration systems with a hydraulic conductivity greater than 600 mm hr are unlikely to support plant growth due to poor water retention and may also result in leaching of pollutants However plant survival might be possible if the outlet pipe were raised to create a permanently submerged zone filter surface area Figure 1 Design elements that influence infiltration capacity Biofiltration Filter Media Guidelines Version 3 01 Prepared by the Facility for Advancing Water Biofiltration FAWB June 2009 FAWB Facility for Adv
12. climatic characteristics or a representative five year period Hobart 1993 6 Hourly mlb Perth 1990 6 Hourly mlb Hobart 1993 6 Minute mlb Perth 1990 6 Minute mib Hobart 1993 Hourly mlb Perth 1990 Hourly mlb Melbourne 1959 6 Hourly mle Sydney 1959 6 Hourly mb Type MLE File Date Modified 20 05 2005 3 01 AM Hd Size 607 KB Files of type Meteorological Template Filez Cancel File name Step 2 Create a pre development source node Create any type of source node it could be urban forested or agriculture since we are only trying to model runoff and not water quality The node should have 1 Appropriate rainfall runoff properties for the location default properties for Melbourne are given in Appendix I of the MUSIC manual 2 A Daily Drainage Rate of O since we wish to calculate the days of surface flows and do not want MUSIC to add in baseflows and a Daily Deep Seepage rate of 5 highlighted FAWB Facility for Advancing Water Biofiltration PIN Wizard Page 1 of 5 x Location Pre developmeni Properties of Pre development Page 2 of 5 x Rainfall Runoff Parameters Impervious rea Propertie reas Rainfall Threshold mm day fi 00 Total Area ha fi 000 Pervious Area Propertie Soil Storage Capacity mm 30 100 Initial Storage of Capacity 30 Field Capacity mm 20 90 80 70 60 50 40 Infiltration Capacity Coeffic
13. heavy sediment loads or other wash off e g cement washings during any construction in the catchment to prevent clogging of the surface of the filter media see Section 3 for more detail Biofiltration System Maintenance Plan EXAMPLE 4 FAWB gt Facility for Advancing Water Biofiltration 3 ESTABLISHMENT PHASE MAINTENANCE A number of maintenance activities have been identified that are in most cases only required during the establishment phase of a biofiltration system The end of the establishment phase can be defined by the completion of both of the following i The plant establishment where plants are suitably established to no longer require irrigation and are close to their mature height and or when larger trees no longer require tree stakes for support This period is typically 18 to 24 months and ii The biofiltration system is completely connected to its intended catchment and the catchment is no longer under construction therefore there is less risk of high sediment loads or other contaminants such as cement washings or fine clay sediments being washed onto the surface of the filter media and causing clogging It is also important that the entire catchment is connected to ensure adequate water availability for plants under normal climatic conditions 3 1 Protection of filter media during construction Construction sites usually generate very high loads of sediment in stormwater runoff These excepti
14. stopwatch is left running as one final flow measurement and water quality sample is collected on the following day approximately 24 hours after the start of the simulation Figure 3 Figure 1 Biofiltration basin at Saturn Crescent October 2006 Water quality samples are collected from each of the five batches of semi synthetic stormwater and combined in equal portions to create a composite sample The 15 outflow water quality samples are analysed individually Parameters that are analysed for include TSS TN NO NH3 DON PON TP FRP Cu Cd Pb and Zn The following volumes are collected for each sample 1 L for TSS 250 mL for TN TP 100 mL filtered for nutrient species and 100 mL for metals The samples for nutrient species are filtered immediately and all samples are stored on ice until they can be delivered to the analytical laboratory Table 2 Target pollutant concentrations for Saturn Crescent rain event simulations Pollutant Concentration mg L Total Suspended Solids TSS 150 Total Nitrogen TN 1 69 Nitrate Nitrite NO 0 59 Ammonia NH3 0 24 Dissolved Organic Nitrogen DON 0 47 Particulate Organic Nitrogen PON 0 39 Total Phosphorus TP 0 31 Copper Cu 0 05 Lead Pb 0 14 Zinc Zn 0 25 Cadmium Cd 0 0045 a d A lt eo 2 4 k ho gt Kl Figure 2 Conducting a rain event simulation at the Saturn Crescent biofiltration system FAWB gt Facility for Advan
15. testing should be conducted every two years or when there has been a significant change in catchment characteristics eg construction without appropriate sediment control REFERENCES Gardner W R 1958 Some steady state solutions of the unsaturated moisture flow equation with application to evaporation from a water table Soil Science 85 228 232 Le Coustumer S T D Fletcher A Deletic and M Potter 2008 Hydraulic performance of biofilter systems for stormwater management lessons from a field study Melbourne Water Corporation available at www monash edu au fawb publications Reynolds W D B T Bowman R R Brunke C F Drury and C S Tan 2000 Comparison of tension infiltrometer pressure infiltrometer and soil core estimates of saturated hydraulic conductivity Soil Science Society of America journal 64 2 478 484 Reynolds W D and D E Elrick 1990 Ponded infiltration from a single ring Analysis of steady flow Soil Science Society of America journal 54 1233 1241 Youngs E G D E Elrick and W D Reynolds 1993 Comparison of steady flows from infiltration rings in Green and Ampt and Gardner soils Water Resources Research 29 6 1647 1650 Single Ring Infiltration Test Site Date O un Constant water level 50 mm Oo gt W vu 2 2 2 n G O O Volume mL Q mL s Time min Volume mL Q mL s Time min FAWB O E
16. these four performance measures are of primary interest It is however important to note that version 3 0 of MUSIC does not account for the presence of a submerged zone at the base of the biofilter Basic modelling process The basic parameters of the biofiltration system should be entered using the MUSIC Bioretention node dialogue box Properties of Bio Retention i Location Bio Retention EE RR Ponding depth typically 0 1 0 3m Low Flow By Pass cubic metres per sec High Flow By pass cubic metres per sec Area of ponded area will be larger than ene 2 filter if ponding area has sloped sides Extended Detention Depth metres Surface Area square metres Infiltration rate of underlying soils 0 if fully lined Seepage Loss mm hr Area of filter Infiltration Properties Filter Area square metres Depth of filter media excluding drainage layer Filter Depth metres Filter Median Particle Diameter mm For loamy sand 0 45 mm is typical Saturated Hydraulic Conductivity Imm hr Depth below underdrain pipe of Filter Depth It is recommended to use a value 90 of Procede the design value ie safety coefficient of 2 Overflow Weir Width metres This allows a buffer store in the base of the Fluxes Notes More system to promote infiltration NOTE It does not account for a saturated zone Length of system if overflow occurs e g perimeter of overflow pit
17. to keep track of the cumulative outflow volume an example spreadsheet is provided with the case study described in Section 4 h Continue to monitor the flow rate and cumulative outflow volume collecting water quality samples at the appropriate intervals The flow rate will change rapidly at first and reach a peak FAWB gt f al ty for Advant ing Water Biofiltration before decreasing The rate of change will also decrease at which point flow measurements intervals can be increased to every five minutes and even longer as flow slows i Flow monitoring and water quality sample collection should continue until the time between samples is deemed too high see case study as a guide this is the end point however consider also taking a final flow measurement and water quality sample the following day i e 24 hours after the start of the simulation j Water quality samples should be analysed by a NATA accredited laboratory 2 5 1 Quality control It is important to collect quality control samples to validate results and eliminate the possibility of sample contamination At least one of each of the following should be collected per simulation e Field blank e Transport blank e Replicate sample For further details see the Australian standard for design of water quality sampling programs Australian New Zealand Standard 1998 3 INTERPRETATION OF RESULTS It is very easy for data to be defective therefore it is esse
18. 470171959 570171959 670171959 7201 1959 85 01 1959 Select Alland Copy Outflow 0000500000 Cu mM Ser 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 Open Microsoft Excel and paste into spreadsheet FAWB gt Facility for Advancing Water Biofiltration Calculate the runoff frequency i e the number of days with non zero flows using the simple Excel functions shown below in the case shown below for Melbourne 1959 the natural runoff frequency is 8 days ES Microsoft Excel Flow frequency calculation sheet Oj x File Edit View Insert Format Tools Data Window Help Adobe PDF sl be IE ga SF 9 ar DH 10 O E H a 4 A Ya es I Outflow cu m sec COUNTIF B2 B366 0 1 01 1959 2 01 1959 3 01 1959 4 01 1959 5 01 1959 6 01 1959 7 01 1959 6 01 1959 9 01 1959 10 01 1959 11 01 1959 12 01 1959 13 01 1959 14 01 1959 15 01 1959 16 01 1959 17 01 1959 16 01 1959 19 01 1959 20 01 1959 21 01 1959 22 01 1959 i gt M initial runoff depth calc examp X 1 year calcu 4 sr Autoshapes N OO 4 S g O w Ar I Days without runoff Runoff frequency days yr COUNTIF B2 B366 lt gt 0 o00000000000000000000 o Modelling the post development runoff frequency Modelling the post development runoff frequency uses the same basic process as describ
19. BIOFILTRATION SYSTEMS FAWB Facility for Advancing Water Biofiltration GUIDELINES FOR FILTER MEDIA IN BIOFILTRATION SYSTEMS Version 3 01 June 2009 The following guidelines for filter media in biofiltration systems have been prepared on behalf of the Facility for Advancing Water Biofiltration FAWB to assist in the development of biofiltration systems including the planning design construction and operation of those systems NOTE This is a revision of the previous FAWB guideline specifications published in 2006 Version 1 01 2008 Version 2 01 It attempts to provide a simpler and more robust guideline for both soil based and engineered filter media FAWB acknowledges the contribution of EDAW Inc Melbourne Water Corporation Dr Nicholas Somes Ecodynamics Alan Hoban South East Queensland Healthy Waterways Partnership Shaun Leinster DesignFlow and STORM Consulting to the preparation of the revised guidelines Disclaimer The Guidelines for Soil Filter Media in Biofiltration Systems are made available and distributed solely on an as is basis without express or implied warranty The entire risk as to the quality adaptability and performance is assumed by the user It is the responsibility of the user to make an assessment of the suitability of the guidelines for its own purposes and the guidelines are supplied on the understanding that the user will not hold EDAW Inc Monash University or parties to the Fac
20. ENDIX B GUIDANCE FOR SIZING BIOFILTRATION SYSTEMS USING MUSIC a IN mn W IMPORTANT e This guide has been written for MUSIC v3 1 and should be used to provide appropriate modelling of biofiltration systems in MUSIC v3 1 Users should refer to the User Guide for guidance on how to model biofiltration systems referred to as bioretention systems in MUSIC v4 MUSIC v4 and later versions uses the results from FAWB s research to take into account the design and operational factors which influence biofiltration treatment performance e g filter media type and depth presence and type of vegetation presence and type of underdrain presence of lining etc In MUSIC v4 the user can readily model model a range of biofiltration systems including designs with a saturated zone or a system without an underdrain i e a vegetated infiltration system Users should refer to the MUSIC User Manual for general guidance on how to model stormwater treatment systems with the MUSIC model In particular Chapter 3 gives step by step instructions on how to model treatment systems including biofiltration systems However this Appendix demonstrates how MUSIC can be used to evaluate the performance of biofilters with regards to 1 Pollutant loads 2 Pollutant concentrations 3 Flow rates 4 Runoff frequency Before using MUSIC to model proposed biofilter designers the objectives need to be clearly defined because the objectives will define which of
21. FAWB DICE Verbene APPENDIX A PUBLICATIONS FAWB gt Fac lity for Advancing Water Biofiltration FAWB PUBLICATIONS Policy and Organisational Receptivity Brown R R and J M Clarke 2007 The transition towards Water Sensitive Urban Design The story of Melbourne Report No 07 01 Facility for Advancing Water Biofiltration Monash University 67 pp Brown R R and M Farrelly 2007 Institutional impediments to advancing sustainable urban water management A typology 13th International Rainwater Catchment Systems Conference and 5th International Water Sensitive Urban Design Conference Sydney Australia Brown R R and J M Clarke 2007 The transition towards water sensitive urban design a socio technical analysis of Melbourne Australia Novatech 2007 6th International Conference on Sustainable Techniques and Strategies in Urban Water Management Lyon France 1 349 356 Brown R R and M A Farrelly 2007 Advancing urban stormwater quality management in Australia A survey of stakeholder perceptions of institutional drivers and barriers Report No 07 05 National Urban Water Governance Program Monash University Available at www urbanwatergovernance com Filter Media Bratieres K T D Fletcher and A Deletic 2009 The advantages and disadvantages of a sand based biofilter medium results of a new laboratory trial 6th International Water Sensitive Urban Design Conference and Hydropolis 3 Per
22. NG TERM MAINTENANCE Three key elements in the design and construction of raingardens and biofiltration tree pits have been identified that strongly influence the amount of long term maintenance that is required Adequately addressing these three key elements ensures that the long term maintenance of these systems is predictable and therefore minimal The elements are Correct filter media specification and installation Dense vegetation cover and Protection during construction phases The importance of these key elements is described in more detail below 2 1 Filter media The filter media for the biofiltration system must meet certain specifications It is crucial that the filter media maintains its hydraulic conductivity i e it s ability to pass water through the media in the long term When an inappropriate filter media is installed eg it contains high levels of fine silt and or clay materials it may result in compaction or even structural collapse of the media This leads to a substantial reduction in the treatment capacity of the system because water will not filter through the media instead it will pond on the surface and spill out through the overflow A symptom of this compaction is often the loss of vegetation within the biofiltration system Similarly filter media must be correctly installed with an appropriate level of compaction during installation Guidelines currently recommend that filter media be lightly compa
23. Water Biofiltration The possible limitations of the test are Reynolds et al 2000 1 the relatively small sample size due to the size of the ring 2 soil disturbance during installation of the ring compaction of the soil and 3 possible edge flow during the experiments 3 INTERPRETATION OF RESULTS This test method has been shown to be relatively comparable to laboratory test methods Le Coustumer et al 2008 taking into account the inherent variability in hydraulic conductivity testing and the heterogeneity of natural soil based filter media While correlation between the two test methods is low results are not statistically different In light of this laboratory and field results are deemed comparable if they are within 50 of each other In the same way replicate field results are considered comparable if they differ by less than 50 Where this is not the case this is likely to be due to a localised inconsistency in the filter media therefore additional measurements should be conducted at different monitoring points until comparable results are achieved If this is not achieved then an area weighted average value may need to be calculated 4 MONITORING FREQUENCY Field testing of hydraulic conductivity should be carried out at least twice 1 One month following commencement of operation and 2 In the second year of operation to assess the impact of vegetation on hydraulic conductivity Following this hydraulic conductivity
24. a APPENDIX F PRACTICE NOTE 2 PREPARATION OF SEMI SYNTHETIC STORMWATER FAWB der la APCE mme CONDITION ASSESSMENT AND PERFORMANCE EVALUATION OF BIOFILTRATION SYSTEMS PRACTICE NOTE 2 Preparation of Semi Synthetic Stormwater Belinda Hatt and Peter Poelsma February 2009 The Facility for Advancing Water Biofiltration FAWB aims to deliver its research findings in a variety of forms in order to facilitate widespread and successful implementation of biofiltration technologies This Practice Note for Preparation of Semi Synthetic Stormwater is part of a series of Practice Notes being developed to assist practitioners with assessing the performance of biofiltration systems Disclaimer Information contained in this Practice Note is believed to be correct at the time of publication however neither the Facility for Advancing Water Bioifltration nor its industry partners accept liability for any loss or damage resulting from its use 1 SCOPE OF THE DOCUMENT This Practice Note for Preparation of Semi Synthetic Stormwater is designed to complement FAWB s Performance Assessment of Biofiltration Systems using Simulated Rain Events Semi synthetic stormwater is also appropriate for laboratory scale testing of biofiltration and other stormwater treatment systems eg porous pavements constructed wetlands 2 INTRODUCTION There are advantages and disadvantages to using either natural or synthetic stormwater for perfor
25. a KS A Y eme pollutants ge flows H 4 LES Le pent HANES os Te ni ypass ia er NEN AR directly to TF A i NT H filters through conventional LL 8 FA media drainage h r system Ts loamy sand filter media sandy transition layer gravel drainage layer containing perforated drainage pipes Figure 1 Conceptual drawing of a biofiltration system illustrating stormwater flow pathways and subsurface infrastructure Biofiltration systems also known as biofilters bioretention systems and rain gardens are designed with the primary intent of removing pollutants from stormwater before the water is discharged to the local waterway or reused for other applications e g irrigation They are typically constructed as basins trenches or tree pits Figure 1 Stormwater runoff generally enters the biofiltration system through a break in a standard road kerb where it temporarily ponds on the surface before slowly filtering through the soil media Treated stormwater is then collected at the base of the biofiltration system via perforated pipes located within a gravel drainage layer before being discharged to conventional stormwater pipes or collected for reuse Note that in some cases the drainage pipe is upturned to create a permanent pool of water or submerged zone in the bottom of the biofiltration system Conventional stormwater pipes also act as an overflow in most designs taking flows that exceed the design capacity of the biofiltration
26. acility for Advancing Water Biofiltration Hatt B E T D Fletcher and A Deletic 2008 Improving stormwater quality through biofiltration Lessons from field studies 11th International Conference on Urban Drainage Edinburgh UK Lewis J F B E Hatt S Le Coustumer A Deletic and T D Fletcher 2008 The impact of vegetation on the hydraulic conductivity of stormwater biofiltration systems 11th International Conference on Urban Drainage Edinburgh UK Hatt B E J Lewis A Deletic and T D Fletcher 2007 Insights from the design construction and operation of an experimental stormwater biofiltration system 13th International Rainwater Catchment Systems Conference and 5th International Water Sensitive Urban Design Conference Sydney Australia Smith N R Allen A McKenzie McHarg A Deletic T D Fletcher and B Hatt 2007 Retrofitting functioning stormwater gardens into existing urban landscapes Cairns International Public Works Conference Cairns Other Blecken G T Y Zinger T M Muthanna A Deletic T D Fletcher and M Viklander 2007 The influence of temperature on nutrient treatment efficiency in stormwater biofilter systems Water Science and Technology 56 10 83 91 Deletic A and G Mudd 2006 Preliminary results from a laboratory study on the performance of bioretention systems built in Western Sydney saline soils Facility for Advancing Water Biofiltration FAWB DDC Fy Annen APP
27. ancing Water Biofiltration Potential issues Required filter area Desirable range 0 100 200 300 400 500 600 700 800 Hydraulic Conductivity mm hr Figure 2 Recommended filter media hydraulic conductivity range and potential issues The infiltration capacity of the biofiltration system will initially decline during the establishment phase as the filter media settles and compacts but this will level out and then start to increase as the plant community establishes itself and the rooting depth increases see Appendix A In order to ensure that the system functions adequately at its eventual minimum hydraulic conductivity a safety co efficient of 2 should be used i e designs should be modelled using half the prescribed hydraulic conductivity If a system does not perform adequately with this hydraulic conductivity then the area and or ponding depth should be increased It may also be desirable to report sensitivity to infiltration rate rather than simply having expected rate This is important when assessing compliance of constructed systems as systems should ideally meet best practice across a range of infiltration rates 2 TESTING REQUIREMENTS 2 1 Determination of Hydraulic Conductivity The hydraulic conductivity of potential filter media should be measured using the ASTM F1815 06 method This test method uses a compaction method that best represents field conditions and so provides a more realistic assessment of hydraulic co
28. at steps e g for this ponding depth Note Since the filter media is already saturated the time required to reach steady infiltration should be less than for the first ponding depth j Record the final water temperature k Enter the temperature time and volume data into a calculation spreadsheet see Practice Note 1 Single Ring Infiltration Test Example Calculations xls available at www monash edu au fawb publications index html as an example 2 4 Calculations In order to calculate K4 a Gardner s behaviour for the soil should be assumed Gardner 1958 in Youngs et al 1993 K h K e Eqn 1 where K is the hydraulic conductivity a is a soil pore structure parameter large for sands and small for clay and h is the negative pressure head Kf is then found using the following analytical expression for a steady flow Reynolds and Elrick 1990 G Q Q er Eqn 2 where a is the ring radius H and H are the first 50 mm and second 150 mm pressure heads respectively Q and Q are the steady flows for the first and second pressure heads respectively and G is a shape factor estimated as G 0 316 2 0 184 Eqn 3 a where d is the depth of insertion of the ring and a is the ring radius G is nearly independent of soil hydraulic conductivity i e Ks and a and ponding if the ponding is greater than 50 mm Measuring hydraulic conductivity FAWB gt f al ty for Advant ing
29. ation water and add laboratory grade chemicals as required The first time sediment is collected pilot study type testing of the slurry needs to be conducted to characterise the sediment pollutant concentration PSD as described in Section 3 3 3 For subsequent collections only the sediment concentration of the slurry needs to be tested 3 1 Target characteristics 3 1 1 Pollutant concentrations There is a high level of spatial and temporal variability in stormwater pollutant concentrations Where local stormwater quality data is available these should be the target pollutant concentrations However where such data is not available typical pollutant concentrations for runoff from urban areas would be appropriate targets Table 1 Table 1 Typical stormwater pollutant concentrations Duncan 1999 Taylor et al 2005 Pollutant Concentration mg L Total Suspended Solids TSS 150 Total Nitrogen TN 2 2 Nitrate Nitrite NO 0 74 Ammonia NH3 0 34 Dissolved Organic Nitrogen DON 0 69 Particulate Organic Nitrogen PON 0 50 Total Phosphorus TP 0 35 Filterable Reactive Phosphorus FRP 0 12 Cadmium Cd 0 0045 Chromium Cr 0 025 Copper Cu 0 05 Lead Pb 0 14 Manganese Mn 0 23 Nickel Ni 0 031 Zinc Zn 0 25 Total Petroleum Hydrocarbons TPH 10 Polyaromatic Hydrocarbons PAH The list of stormwater pollutants presented in Table 1 is by no means exhaustive however these are the pollutants that are of most conc
30. cants declared plants and local weeds as listed in local guidelines Acts and should not be hydrophobic The filter media should contain some organic matter for increased water holding capacity but be low in nutrient content In the case of natural or amended natural soils the media should be a loamy sand Biofiltration Filter Media Guidelines Version 3 01 Prepared by the Facility for Advancing Water Biofiltration FAWB June 2009 FAWB gt Facility for Advancing Water Biofiltration Maintaining an adequate infiltration capacity is crucial in ensuring the long term treatment efficiency of the system The ability of a biofiltration system to detain and infiltrate incoming stormwater is a function of the filter surface area extended detention ponding depth and the hydraulic conductivity of the filter media Figure 1 Most importantly design of a biofiltration system should optimize the combination of these three design elements For a biofiltration system in a temperate climate with an extended detention depth of 100 300 mm and whose surface area is approximately 2 of the connected impervious area of the contributing catchment the prescribed hydraulic conductivity will generally be between 100 300 mm hr in order to meet best practice targets Figure 2 This configuration supports plant growth without requiring too much land space In warm humid sub and dry tropical regions the hydraulic conductivity may need to
31. cing Water Biofiltration 0 6 flow O water quality sample 0 5 0 4 flow L s 2 CO D 0 1 0 0 0 60 120 180 240 300 360 420 480 540 600 660 720 780 840 900 960 1020 1080 1140 1200 1260 time minutes Figure 3 Typical hydrograph for a rain event simulation at the Saturn Crescent biofiltration system showing water quality sample collection times REFERENCES Australian New Zealand Standard 1998 AS NZS 5667 1 1998 Water quality Sampling Part 1 Guidance on the design of sampling programs sampling techniques and the preservation and handling of samples Homebush New South Wales Standards Australia Hatt B E T D Fletcher and A Deletic 2009 Hydrologic and pollutant removal performance of stormwater biofiltration systems at the field scale Journal of Hydrology 365 3 4 310 321 Wong T H F Ed 2006 Australian Runoff Quality A Guide To Water Sensitive Urban Design Sydney Engineers Australia FAWB MO Fey vanen APPENDIX H MAINTENANCE REQUIREMENTS FOR BIOFILTRATION SYSTEMS FIELD SHEET MAINTENANCE REQUIREMENTS FOR BIOFILTRATION SYSTEMS tree species tolerant of drought and inundation NOT TO SCALE public seating also addressi bollards providing trip hazard ground cover inspection protection from VM vegetation SA traffic E A MANG 7 break in NN d Hit kerb HA Nui AY Mat HA un road pe lg o an e
32. cted during installation to prevent migration of fine particles In small systems a single pass with a vibrating plate should be used to compact the filter media while in large systems a single pass with roller machinery e g a drum lawn roller should be performed FAWB 2009 2 2 Vegetation cover Nutrients have been identified as a key pollutant in stormwater particularly nitrogen and phosphorus The nutrient removal efficiency of biofiltration systems is related to the root structure and density of the plants within the system Further as plants mature and their roots penetrate the filter media they play a role in maintaining the hydraulic conductivity of the media because root growth helps to maintain the surface porosity and the infiltration capacity of the filter media Asa result it is important that dense vegetation cover is established at an early stage to prevent compaction or surface sealing Some biofiltration tree pits are designed without understorey vegetation In these instances it is likely that additional maintenance will be required to maintain the porosity of the surface of the filter media e g physical removal of any fine sediments that accumulate on the surface 2 3 Protection during construction phases Protection of biofiltration systems during construction allows for good plant establishment and prevents disturbance or scour of the filter media surface It is also important to protect the biofiltration system from
33. d for Poor plant health can be a sign of too much or too little e Check inlet and overflow levels are correct and reset as required die off aesthetics water or poor flow control For too much water e Replace plants with species more tolerant of wet conditions OR e Replace filter media with that of a higher infiltration capacity For too little water e Consider installing a choke on the outlet OR e Replant with species more tolerant of dry conditions Check that original plant densities are 3 monthly or as desired for Plants are essential for pollutant removal and maintaining Carry out infill planting as required plants should be evenly spaced to help prevent maintained aesthetics drainage capacity Plants should be close enough that scouring due to a concentration of flow their roots touch each other 6 10 plants m is generally adequate A high plant density also helps prevent ingress of weeds Check for presence of weeds 3 monthly or as desired for Weeds can reduce aesthetics and treatment capacity Manually remove weeds where possible where this is not feasible spot spray weeds aesthetics because some plants are more effective at pollutant with a herbicide appropriate for use near waterways removal than others DRAINAGE SS y O Check that underdrain is not blocked with 6 monthly after rain Filter media and plants can become waterlogged if the e Clear underdrain as required using a pipe snake or water jet sediment or roots und
34. d safety glasses Personnel should also have received necessary vaccinations consult a general practitioner or health advisor for further information 3 3 2 Procedure a Place the sieve on top of the collection vessel FAWB gt f al ty for Advant ing Water Biofiltration b Place several scoops of sediment on the sieve c Pour a cup of water over the sediment d Use spatula or squeegee to stir sediment around allowing water to wash particles through to the collection chamber e Wash and stir the sediment in the sieve with ten cups of water then discard the fraction that did not pass through the sieve Note When all the clean water has washed through the sieve use the cup to scoop up supernatent liquid from the collection vessel avoid scooping up settled sediment and use this liquid to wash the sediment in the sieve stirring with the spatula while doing so f Repeat Steps b to e until the required volume of slurry plus some extra for analysis has been prepared 3 3 3 Analysis The first time sediment is collected from a stormwater pond all of the tests described below must be carried out in order to characterise the sediment For subsequent collections only the sediment concentration of the slurry needs to be analysed provided that inflow samples of the stormwater are collected during testing Sediment concentration The method for measuring the sediment concentration of the slurry is an adaptation of the Austral
35. e infiltration rate is considered steady i e when the volume poured per time interval remains constant for at least 30 minutes This method has been used extensively eg Reynolds and Elrick 1990 Youngs et al 1993 Note This method measures the hydraulic conductivity at the surface of the filter media In most cases it is this top layer which controls the hydraulic conductivity of the system as a whole i e the underlying drainage layer has a flow capacity several orders of magnitude higher than the filter media as it is this layer where fine sediment will generally be deposited to form a clogging layer However this shallow test would not be appropriate for systems where the controlling layer is not 1 FAWB gt Facility for Advancing Water Biofiltration the surface layer eg where migration of fine material down through the filter media has caused clogging within the media In this case a deep ring method is required for further information on this method see Le Coustumer et al 2008 2 1 Selection of monitoring points For biofiltration systems with a surface area less than 50 m in situ hydraulic conductivity testing should be conducted at three points that are spatially distributed Figure 1 For systems with a surface area greater than 50 m an extra monitoring point should be added for every additional 100 m It is essential that the monitoring point is flat and level Vegetation should
36. ed for the pre development situation Step 1 Select or create the appropriate climate template Select the same 6 minute timestep climate template as used for the pre development analysis Step 2 Create the model with impervious areas and proposed treatment systems Whilst you may model pervious areas for the normal MUSIC modelling to analyse removal of TSS TP and TN you need only include the impervious areas when modelling runoff frequency If you include pervious areas with a daily baseflow rate set they will produce baseflow which MUSIC will interpret as contributing to daily runoff frequency therefore if you include pervious areas the daily baseflow rate should be set to zero and the daily seepage rate set to 5 as per Step 2 for the pre development frequency analysis Create the network of treatment systems to retain stormwater from these impervious areas eg rain garden rainwater tank infiltration system The example below shows a rainwater tank being used to harvest water from a house roof with overflow going to a rain garden biofiltration system Runoff from the paved area also goes to the biofiltration system FAWB gt Facility for Advancing Water Biofiltration SE MUSIC Model for Urban Stormwater Improvement Conceptualisation SCIFFA gt 1 10 x File Edit Catchment Tools Window Help 5 x pa Source Treatment Other Nodes Nodes Nodes Paved area Rainwater Ta T
37. ed rooting depth counters the effects of compaction and clogging 350 300 250 200 150 100 50 hydraulic conductivity mm hr 0 0 2 4 6 8 10 12 14 16 18 20 time months Figure A 1 Evolution of hydraulic conductivity during the first 20 months of a biofiltration system after Hatt et al 2009 Biofiltration Filter Media Guidelines Version 3 01 Prepared by the Facility for Advancing Water Biofiltration FAWB June 2009 FAWB DDC CC water Bioitration APPENDIX D EXAMPLE MAINTENANCE PLAN MO Fa Biofiltration Systems MAINTENANCE PLAN EXAMPLE June 2009 FAWB gt Facility for Advancing Water Biofiltration Table of Contents 1 BJ OFILTRATION SYSTEM FUNCTIONS u 2 2 MINIMISING LONGTERM MAINTENANCE cc ssssccceccssecccccseseccccesaesececessenseceessuaneeeessaaaeeeeeseas 4 2 1 SL ee ee 4 2 2 Vegetation COVED iniciara 4 2 3 Protection during construction phases sise 4 3 ESTABLISHMENT PHASE MAINTENANCE rsumnnnnnnnnrrnnnnnnnrrrnnnnnnnsrnnnnnnnnsvnnnnnnnnsrnnnnnnnssrnnnnnnsnssnnnnnnnssnnne 5 3 1 Protection of filter media during construction ss 5 3 2 EN 6 3 3 ee 6 4 LONG TERM MAINTENANCE TASKS rrerrervennnnnrervnnnnnnsensnnnnnnsennnnnnnnsensnnnnnssensnnnnnnsensnnnnnssensnnnnnssenennnen 7 4 1 SRE OEN ps 7 4 1 1 Schedule of Site Visits Regular Inspec amp Maint oooccnnnccnnnccnnnnnnnnncnnnnnonarinnnnnonaninonnss 7 4 2 IK EN ENE NE EN 7 4 2 1 FILTER MEDIA TASKS au ee n
38. en 7 4 2 2 CORTE SR a a te ee 7 4 2 3 DRAINAGE TA K ernn a E een ee 8 4 2 4 OTHER POT hr 8 4 2 5 FORM REGULAR INSPECTION MAINTENANCE un 9 S REFERENCES aan ps see nena nna cise ane od pea ee Gen 11 Biofiltration System Maintenance Plan EXAMPLE i FAWB gt Facility for Advancing Water Biofiltration 1 BIOFILTRATION SYSTEM FUNCTIONS This is a sample maintenance plan only When preparing a maintenance plan for a specific site consideration should be given to the individual site requirements to ensure all the elements within a particular design are incorporated in to the plan A sketch or drawing should be provided as seen in Figure 1 to help maintenance personnel and asset managers understand the function and features of a particular asset The drawing should provide enough information about the function of a system to enable appropriate management maintenance decisions to be made Biofiltration systems also known as biofilters bioretention systems and rain gardens are designed with the primary intent of removing pollutants from stormwater before the water is discharged to the local waterway or reused for other applications e g irrigation They are typically constructed as basins trenches or tree pits Figure 1 Stormwater runoff generally enters the biofiltration system through a break in a standard road kerb where it temporarily ponds on the surface before slowly filtering through the soil media Treated stormwat
39. er is then collected at the base of the biofiltration system via perforated pipes located within a gravel drainage layer before being discharged to conventional stormwater pipes or collected for reuse Note that in some cases the drainage pipe is up turned to create a permanent pool of water or submerged zone in the bottom of the biofiltration system Conventional stormwater pipes also act as an overflow in most designs taking flows that exceed the design capacity of the biofiltration system The inclusion of biofiltration systems into the stormwater drainage system does not affect other conventional drainage elements Stormwater discharge that exceeds the capacity of the biofiltration system may continue down the kerb to be collected in a conventional side entry pit or may overflow into a pit located within the biofiltration system that is directly connected to the conventional drainage system Biofiltration systems provide stormwater treatment as well as landscape amenity An additional benefit is that the passive irrigation from stormwater reduces the demand for irrigation from other sources such as potable water The tree and or understorey species need to be relatively hardy and tolerant of both freely draining sandy soils and regular inundation The soil filter media into which the trees are planted generally has a specified hydraulic conductivity of 100 300 mm hr depending on the local climate and the configuration of the system In t
40. erdrain is choked or blocked Remote camera CCTV e Water jets should be used with care in perforated pipes inspection of pipelines could be useful Check that the water level in the submerged 6 monthly after rain Drawdown during dry periods is expected e Check outflow level is correct and reset as required zone if applicable is at the design level Check that inflow areas weirs and grates over Monthly and occasionally A blocked grate or inlet would cause nuisance flooding e Replace dislodged or damaged pit covers as required pits are clear of litter and debris and in good after rain and safe condition e Remove sediment from pits and entry sites likely to be an irregular occurrence in mature OTHER IN NN Observe biofiltration system after a rainfall Twice a year after rain Ponding on the filter media surface for more than a few Check catchment land use and assess whether it has altered from design capacity IE g event to check drainage hours after rain is a sign of poor drainage unusually high sediment loads may require installation of a sediment forebay FAWB CC Facility for Advancing Water Biofiltration FAWB Office Monash University Department of Civil Engineering Building 60 Clayton Campus MONASH UNIVERSITY VIC 3800 Australia Phone 61 3 9905 4957 Fax 61 3 9905 5033 fawb eng monash edu au www monash edu au fawb The Facility for Advancing Water Biofiltration FAWB is a joint venture researc
41. ern where the management objective is protection of aquatic ecosystems It may not be possible to analyse for all of these pollutants depending on the available budget however the minimum suite of pollutants should include TSS TN TP Cd Cu Pb Zn If reuse is planned pathogens are a key water quality issue and should be considered as an additional pollutant 3 1 2 Particle size distribution The PSD of stormwater sediment varies widely according to catchment characteristics as well as rainfall patterns and intensity Like pollutant concentrations local information should form the basis 1 A Mains or recycled water is suitable FAWB gt f al ty for Advant ing Water Biofiltration of appropriate targets however where this data does not exist it would be appropriate to aim for a median particle size d o of 25 60 um Siriwardene et al 2007 Note Given the large spatial and temporal variation in PSDs it is neither feasible nor justified to try to match an exact PSD However many stormwater pollutants are known to attach to very small particles eg heavy metals are strongly correlated to particles that are lt 15 um Sansalone amp Buchberger 1995 therefore it should be ensured that this fraction is adequately represented 5 15 of weight fraction 3 2 Collection of stormwater sediment Collect sediment from near but a short distance from the inlet of a stormwater pond or wetland using a shovel sed
42. es in the underlying drainage layer 100 mm sand plus 200 mm gravel convey the treated water to a side entry pit which is connected to the existing storm drainage system This design storm for this system is a 3 month ARI with a duration of 15 minutes which equates to a volume of 3000 L Semi synthetic stormwater is prepared in five 600 L batches using mains water supplied by a tanker slurry and chemicals Figure 2a b and c and see Practice Note 2 for further details on semi synthetic stormwater preparation The target pollutant concentrations match typical stormwater quality for Brisbane Table 2 The semi synthetic stormwater is stirred in the tank using a kayak paddle during preparation and as the water is discharged to the biofilter Figure 2d and e It takes approximately 25 minutes to prepare and discharge the five batches to the biofilter Figure 2f and g Outflow appears 20 25 minutes after the beginning of the simulation i e when the first batch of semi synthetic stormwater is discharged to the biofilter Flow is measured every two minutes until the peak has passed Figure 3 Water quality samples are collected every 150 L Figure 3 This equates to samples being collected every five minutes or so at 6 FAWB gt Facility for Advancing Water Biofiltration the peak of the hydrograph and extending to 50 minutes between samples by the 14th sample At this point the simulation is finished for the day however the
43. etres per sec 1 00 000 Inlet Properties Er Properties Low Flow By pass cubic metres per sec Extended Detention Depth metres 0 30 High Flow By pass cubic metres per sec Surface Area square metres 2 0 Storage Properties Seepage Loss mm hr 36 00 Surface Area square metres Depth to Overflow Weir metres Infiltration Properties Filter Area square metres Infiltration Rate mm hr Filter Depth metres Evaporative Loss as of PET DQutlet Properties Overflow Weir Width metres Re use Fluxes ii Filter Median Particle Diameter mm Saturated Hydraulic Conductivity mm hr Depth below underdrain pipe of Filter Depth r Outlet Properties Overflow Weir Width metres Fluxes Notes More X Cancel lt Bach af Finish Step 3 Run model and export results Run the model Export the results from the most downstream node in the example above this would be the rain garden at daily timestep selecting only flow and choosing the Tab delimited format FAWB gt Facility for Advancing Water Biofiltration Step 4 Import and analyse results Follow the same steps as per the pre development frequency open the exported text file in Notepad Select All and then Copy paste into Excel and then calculate the runoff frequency ie the number of days with non zero flows The number of days per year with non zero flo
44. fall events 4 TRANSITION LAYER The transition layer prevents filter media from washing into the drainage layer Transition layer material shall be a clean well graded sand material containing lt 2 fines To avoid migration of the filter media into the transition layer the particle size distribution of the sand should be assessed to ensure it meets bridging criteria that is the smallest 15 of the sand particles bridge with the largest 15 of the filter media particles Water by Design 2009 VicRoads 2004 D s transition layer lt 5 x Das filter media where D transition layer is the 15 percentile particle size in the transition layer material i e 15 of the sand is smaller than D mm and Das filter media is the 85 percentile particle size in the filter media Biofiltration Filter Media Guidelines Version 3 01 Prepared by the Facility for Advancing Water Biofiltration FAWB June 2009 FAWB Facility for Advancing Water Biofiltration A dual transition layer where a fine sand overlays a medium coarse sand is also possible While it is acknowledged that this can increase the complexity of the construction process testing indicates that a dual transition layer produces consistently lower levels of turbidity and concentrations of suspended solids in treated outflows than a single transition layer Therefore it is recommended that this design be specified for stormwater harvesting applications
45. filter medium A washed well graded sand with an appropriate hydraulic conductivity should be used as the filter medium Suitable materials include those used for the construction of turf profiles e g golf greens these materials are processed by washing to remove clay and silt fractions In large quantities gt 20 m they can be obtained directly from sand suppliers while smaller quantities can be purchased from local garden yards The top 100 mm of the filter medium should then be ameliorated with appropriate organic matter fertiliser and trace elements Table 1 This amelioration is required to aid plant establishment and is designed to last four weeks the rationale being that beyond this point the plants receive adequate nutrients via incoming stormwater Table 1 Recipe for ameliorating the top 100 mm of sand filter media Constituent Quantity kg 100 m filter area Granulated poultry manure fines 50 Superphosphate 2 Magnesium sulphate 3 Potassium sulphate 2 Trace Element Mix 1 Fertilizer NPK 16 4 14 4 Lime 20 Laboratory testing has shown that biofilters that contain an engineered filter medium will achieve essentially the same hydraulic and treatment performance as those containing a soil based filter medium Bratieres et al 2009 However it is recommended that a submerged zone be included in biofiltration systems that utilise such a free draining filter medium to provide a water source for vegetation between rain
46. formation contained in this Practice Note is believed to be correct at the time of publication however neither the Facility for Advancing Water Bioifltration nor its industry partners accept liability for any loss or damage resulting from its use 1 SCOPE OF THE DOCUMENT This Practice Note for n Situ Measurement of Hydraulic Conductivity is designed to complement FAWB s Guidelines for Filter Media in Biofiltration Systems Version 3 01 visit http www monash edu au fawb publications index html for a copy of these guidelines However the recommendations contained within this document are more widely applicable to assessing the hydraulic conductivity of filter media in existing biofiltration systems For new systems this Practice Note does not remove the need to conduct laboratory testing of filter media prior to installation 2 DETERMINATION OF HYDRAULIC CONDUCTIVITY The recommended method for determining in situ hydraulic conductivity uses a single ring infiltrometer under constant head The single ring infiltrometer consists of a small plastic or metal ring that is driven 50 mm into the filter media It is a constant head test that is conducted for two different pressure heads 50 mm and 150 mm The head is kept constant during all the experiments by pouring water into the ring The frequency of readings of the volume poured depends on the filter media but typically varies from 30 seconds to 5 minutes The experiment is stopped when th
47. gure 2 Protection of filter media with a geofabric and turf cover left and use of a sacrificial sediment forebay during construction and plant establishment right Biofiltration System Maintenance Plan EXAMPLE 5 FAWB gt Facility for Advancing Water Biofiltration 3 2 Irrigation Plants and trees in biofiltration systems will probably require irrigation during the establishment phase Irrigation should be applied directly to the surface of the filter media The use of Ag pipes for irrigating young trees is not recommended as it creates a short circuit pathway or preferential flow path for stormwater The stormwater flows straight down the Ag pipes and into the drainage layer at the base where it is conveyed downstream to the conventional stormwater system effectively bypassing any pollutant removal processes that occur as the stormwater filters through the filter media Figure 3 Ag pipe for tree irrigation NOT TO SCALE Figure 3 Concept illustration showing how Ag pipes installed for tree watering can result in short circuiting and reduced stormwater treatment 3 3 Tree stake removal Tree stakes are often used to support young trees planted into the filter media of biofiltration systems The stakes should be removed once the trees are adequately established and the holes filled in with filter media Failure to fill in the holes will result in the creation of a short circuit pathway or preferential flow path fo
48. h facility between EDAW Australia and Monash University under the auspices of the Victorian Government s Science Technology and Innovation Initiative Collaborators Adelaide and Mount Lofty Ranges Natural Resources Management Board SA Brisbane City Council Qld Landcom NSW Manningham City Council Vic Melbourne Water Vic VicRoads Vic Victoria The Place To Be
49. he case of tree pits the understorey or groundcover vegetation reduces the likelihood of clogging at the surface of the filter media Figure 1 illustrates the intended flow pathways for stormwater through a typical biofiltration system a tree pit in this case and shows some of the subsurface infrastructure that requires consideration for maintenance Biofiltration System Maintenance Plan EXAMPLE 2 FAWB gt Facility for Advancing Water Biofiltration tree species tolerant of drought and inundation NOT TO SCALE public seating also addressing bollards providing trip hazard ground cover TEN po kr prete from traffic MD Vi VE M Ai VY break in N AL AN Ma Dirt ply road gt ag ht plant roots NE Son RR BI s pollutants large flows 1 N amp SNE Pre mise ke knit a OK RD TR stormwater I N GO W FATUA filters through directly to JER HEN V DNS gt i roug conventional LE I il Ca Va l 4 y N I T ot media drainage AIA 1 NE system o a Rive 2 7 ns e ann ond filter media sandy transition layer gravel drainage layer containing perforated drainage pipes Figure 1 Conceptual drawing of a biofiltration system illustrating stormwater flow pathways and subsurface infrastructure requiring maintenance Biofiltration System Maintenance Plan EXAMPLE 3 FAWB gt Facility for Advancing Water Biofiltration 2 MINIMISING LO
50. ian Standard method for determination of total solids in waters Australian Standard 1990 Rapidly stir the slurry so that all particles are in suspension and immediately collect three 100 mL samples of the slurry continue stirring between each sample collection transfer each sample to a pre weighed container and dry in an oven at 105 for one hour Allow the containers to cool at room temperature before weighing again Calculate the sediment concentration of each sample using Equation 1 and determine the average Equation 1 where c sediment concentration in slurry mg L Mes dry mass of container slurry mg m mass of container mg v volume of slurry 0 1L Note The target sediment concentration should be around 300 200 g L Particle size distribution There is a high level of uncertainty associated with measurement of the PSD and low levels of agreement between test methods Consistently using the same test method is therefore more important than the actual test method PSD is typically measured using sieving techniques or particle sizers given that both methods have their advantages and disadvantages it is recommended that the test method that is most readily available and convenient be adopted and then used consistently for all subsequent tests FAWB gt f al ty for Advant ing Water Biofiltration Pollutant concentration A sub sample of the slurry should be mixed with water to achieve the target TSS co
51. ient Infiltration Capacity Exponent b Groundwater Propertie Initial Depth mm Daily Recharge Rate Daily Baseflow Rate Daily Deep Seepage Rate 30 20 10 0 X Cancel Back Step 3 Run model and export results Run the model Export the results at delimited format SS MUSIC Model for Urban Stormwater Improvement Conceptualisation Example for guide File Edit Catchment Tools Window Help daily timestep selecting only flow and choosing the Tab sjef x REIT ur fel x a o Export Setup i x Time Step Edit Properties Ctri E Dail Hourly Pre devel Delete Ctrl Del 12 Hourly C 30 Minute Select all Ctrl 4 6 Hourly C 12 Minute Select none 3 Hourly C 6 Minute Inflowr Outflow Flow Based Sub Sample Bounds FH F Flo ow 150 Observed Data u I 755 I TSS Time Series Graphs DATE I TF Statistics El TRI F TN Cumulative Frequency Graphs E 155 Laa I TSS Load Export to MS Excel E2 etc E 1 Load J TP Load IT TN Load F TN Load 7 Grass Pollutant Load I Gross Pollutant Load Format Space delimited vo Tab delimited Comma delimited x Cancel Step 5 Import and analyse results Open the export file in Notepad just double click on the created text file Pre development Notepad z OI xj File Edit Format wiew Help Date 1 01 1959 270171959 370171959
52. ility for Advancing Water Biofiltration FAWB the Licensor liable for any loss or damage resulting from their use To the extent permitted by the laws of Australia the Licensor disclaims all warranties with regard to this information including all implied warranties of merchantability and fitness In no event shall the Licensor be liable for any special direct or consequential damages or any damages whatsoever resulting from loss or use whether in action of contract negligence or other tortious action arising out of the use of or performance of this information 1 GENERAL DESCRIPTION The biofiltration filter media guidelines require three layers of media the filter media itself 400 600 mm deep or as specified in the engineering design a transition layer 100 mm deep and a drainage layer 50 mm minimum cover over underdrainage pipe The biofiltration system will operate so that water will infiltrate into the filter media and move vertically down through the profile The filter media is required to support a range of vegetation types from groundcovers to trees that are adapted to freely draining soils with occasional wetting The material should be based on natural or amended natural soils or it can be entirely engineered in either case it can be of siliceous or calcareous origin In general the media should have an appropriately high permeability under compaction and should be free of rubbish deleterious material toxi
53. iment very close to the inlet is dominated by coarse sand and gravel Slowly scrape the surface of the sediment layer this is the freshest sediment i e it has most recently been stormwater taking care to minimise disturbance The amount of sediment that needs to be collected will depend on the volume of stormwater to be prepared as a general guide 5 L of sediment will make 3000 L of semi synthetic stormwater 3 3 Preparation and analysis of sediment slurry A slurry is a concentrated mixture of sediment and water This is prepared by wet sieving the sediment using a small volume of water 3 3 1 Apparatus The following apparatus is required e Scoop e Sieve see below for guidance on appropriate size e Collection vessel e Small cup or beaker e Spatula or rubber squeegee e Water Biofilters and other stormwater treatment structures may or may not incorporate pre treatment Where systems do not have pre treatment facilities a 1 mm sieve should be used to remove very large particles while a 300 um sieve should be used for systems that do have pre treatment The aim of this procedure is to try to replicate the realistic nature of the inflow sediment that will enter the biofiltration system in operation Caution Stormwater sediment potentially contains pathogens and while the risk of falling ill is low appropriate protocols for safe handling of environmental samples should be followed including long gloves covered skin an
54. ion System Maintenance Plan EXAMPLE 7 densities FAWB gt Facility for Advancing Water Biofiltration Planting should be evenly spaced to help prevent scouring due to a concentration of flow Frequency 3 MONTHLY OR AS DESIRED FOR AESTHETICS It is important to identify the presence of any rapidly spreading weeds as they occur The presence of such weeds can reduce dominant species distributions and diminish aesthetics Weed species can also compromise the systems long term performance Inspect for and manually remove weed species Application of herbicide should be limited to a wand or restrictive spot spraying due to the fact that rain gardens and biofiltration tree pits are directly connected to the stormwater system Frequency 3 MONTHLY OR AS DESIRED FOR AESTHETICS 4 2 3 DRAINAGE TASKS Underdrain High flow inlet pits overflow pits and other stormwater junction pits Ensure that underdrain pipes are not blocked to prevent filter media and plants from becoming waterlogged If a submerged zone is included check that the water level is at the design level noting that drawdown during dry periods is expected A small steady clear flow of water may be observed discharging from the underdrain at its connection into the downstream pit some hours after rainfall Note that smaller rainfall events after dry weather may be completely absorbed by the filter media and not result in flow Rem
55. ld be mixed in a tank and stirred continuously this can be mechanical or manual It is important that the stormwater is mixed for at least ten minutes to allow for the adsorption of various pollutants to particles in the mixture the proportion of dissolved and particulate pollutants has a major influence on treatment performance Slurry can be prepared and kept for several weeks if refrigerated in a container with a secure lid to reduce evaporation however stormwater should be used on the day it is prepared REFERENCES Australian Standard 1990 AS 3550 4 1990 Waters Part 4 Determination of solids Gravimetric method Homebush New South Wales Standards Australia Deletic A and T D Fletcher 2006 Performance of grass filters used for stormwater treatment a field and modelling study Journal of Hydrology 317 3 4 261 275 Duncan H P 1999 Urban Stormwater Quality A Statistical Overview Melbourne Australia Cooperative Research Centre for Catchment Hydrology 80 Sansalone J J and S G Buchberger 1995 An infiltration device as a best management practice for immobilizing heavy metals in urban highway runoff Water Science and Technology 32 1 119 125 Siriwardene N R A Deletic and T D Fletcher 2007 Clogging of stormwater gravel infiltration systems and filters insights from a laboratory study Water Research 41 7 1433 1440 Taylor G D T D Fletcher T H F Wong P F Breen and H P Duncan
56. let if necessary Frequency 3 MONTHLY AFTER RAIN Filter media Inspect for the accumulation of an impermeable layer such as oily or clayey surface sediment that may have formed on the surface of the filter media A symptom may porosity be that water remains ponded in the biofiltration system for more than a few hours after a rain event Repair minor accumulations by raking away any mulch on the surface and scarifying the surface of the filter media between plants For biofiltration tree pits without understorey vegetation any accumulation of leaf litter should be removed to help maintain the surface porosity of the filter media Frequency 3 MONTHLY AFTER RAIN Litter control Check for litter including organic litter in and around treatment areas Remove both organic and anthropogenic litter to ensure flow paths and infiltration through the filter media are not hindered Frequency 3 MONTHLY OR AS DESIRED FOR AESTHETICS 4 2 2 HORTICULTURAL TASKS Pests and Assess plants for disease pest infection stunted growth or senescent plants Treat or diseases replace as necessary Reduced plant density reduces pollutant removal and infiltration performance Frequency 3 MONTHLY OR AS DESIRED FOR AESTHETICS Maintain Infill planting Between 6 and 10 plants per square metre should depending on original plant species be adequate to maintain a density where the plants roots touch each other Biofiltrat
57. mance assessment The advantage of using natural stormwater i e stormwater collected from a drainage outlet is that the physical chemical and biological characteristics will be truly representative of real stormwater However the disadvantage is that maintaining consistency of concentration and characteristics eg sediment particle size distribution PSD will be very difficult potentially introducing an artefact of inflow variations into the measurement of treatment performance Collection of natural stormwater can be logistically difficult and is dependent on rain events an almost certain complication to any monitoring program The advantage of using synthetic i e using laboratory chemicals stormwater is that is readily available and will better achieve consistency however it will introduce artefacts due to unnatural composition Deletic amp Fletcher 2006 Semi synthetic stormwater represents an appropriate compromise because it is prepared using sediment sourced from a stormwater pond Since it is actual stormwater sediment this should also largely achieve desired nutrient and heavy metal concentrations any deficiencies can then be topped up using laboratory grade chemicals 3 METHODOLOGY The basic procedure in preparing semi synthetic stormwater is to collect sediment from a stormwater pond prepare a slurry of known sediment concentration mix this with dechlorinated FAWB gt f al ty for Advant ing Water Biofiltr
58. me therefore water quality samples need to be collected at regular intervals in order to obtain a representative water quality assessment of the entire rain event These water quality samples can then be analysed individually or combined the latter option will cost significantly less but will give less information about the performance of the system 12 15 water quality samples collected over the entire duration of outflow will suffice Calculate the sampling interval by dividing the event volume by the number of samples to be collected event volumex 0 7 int erval no samples 3000 Lx0 7 _ int erval 150L e g The 0 7 multiplier allows for a fraction of the inflow to be retained by the system which has been demonstrated to be in the order of 30 Hatt et al 2009 The total number of samples collected would be 15 including at the start of outflow 2 3 Selection of water quality parameters The pollutants that should be monitored will be determined by the system objectives and the type of receiving water In general the following parameters should be measured as a minimum e Total suspended solids TSS e Total nitrogen TN e Total phosphorus TP and e Heavy metals copper Cu cadmium Cd lead Pb and zinc Zn Physical parameters such as pH electrical conductivity EC as a measure of salinity temperature and dissolved oxygen DO are relatively cheap and easy to measure using a field probe and chould
59. ncentration see Section 3 5 for guidance on calculating the required volumes A sample of this should then be analysed for all the pollutants of interest by a NATA accredited laboratory 3 4 Addition of laboratory grade chemicals Once the pollutant concentration of the slurry water mix has been determined the need for topping up pollutant concentrations can be assessed Where this is required laboratory grade chemicals should be used The chemicals that should be used for each pollutant are listed in Table 2 see Section 3 5 for guidance on calculating the required amount to add Table 2 Chemicals for topping up stormwater pollutant concentrations Note that it is important to use these particular chemicals due to solubility considerations e g Lead Pb forms an insoluble salt with sulphate SO and chloride CI Pollutant Compound to dose with TN n a NO potassium nitrate KNO NH3 ammonium chloride NH Cl DON nicotonic acid CgH5O2N PON n a TP n a FRP potassium phosphate KH PO Cd 1000 mg L standard solution Cr chromium nitrate Cr NO Cu copper sulphate CuSO Pb lead nitrate Pb NO Mn manganese nitrate Mn NO Ni nickel nitrate Ni NO Zn zinc chloride ZnCl TPH amp PAH diesel TN is the sum of NO NH3 DON and PON if the targets concentrations of these constituents are met then the target TN concentration will also be achieved PON is sourced from the slurry while TP is the sum
60. ncing Water Biofiltration Fletcher T D Y Zinger and A Deletic 2007 Treatment efficiency of biofilters results of a large scale biofilter column study 13th International Rainwater Catchment Systems Conference and 5th International Water Sensitive Urban Design Conference Sydney Australia Submerged Zone Blecken G T Y Zinger A Deletic T D Fletcher and M Viklander in press Influence of intermittent wetting and drying conditions on heavy metal removal by stormwater biofilters Water Research Blecken G T Y Zinger A Deletic T D Fletcher and M Viklander 2009 Impact of a submerged anoxic zone and a cellulose based carbon source on heavy metal removal in stormwater biofiltration systems Ecological Engineering 35 5 769 778 Zinger Y T D Fletcher A Deletic G T Blecken and M Viklander 2007 Optimisation of the nitrogen retention capacity of stormwater biofiltration systems Novatech 2007 6th International Conference on Sustainable Techniques and Strategies in Urban Water Management Lyon France Zinger Y A Deletic and T D Fletcher 2007 The effect of various intermittent wet dry cycles on nitrogen removal capacity in biofilters systems 13th International Rainwater Catchment Systems Conference and 5th International Water Sensitive Urban Design Conference Sydney Australia Hydraulic Performance Le Coustumer S T D Fletcher A Deletic S Barraud and J F Lewis in press Hydraulic
61. nductivity than other test methods Note if a hydraulic conductivity lower than 100 mm hr is prescribed the level of compaction associated with this test method may be too severe and so underestimate the actual hydraulic conductivity of the filter media under field conditions However FAWB considers this to be an appropriately conservative test and recommends its use even for low conductivity media 2 2 Particle Size Distribution Particle size distribution PSD is of secondary importance compared with hydraulic conductivity A material whose PSD falls within the following recommended range does not preclude the need for hydraulic conductivity testing i e it does not guarantee that the material will have a suitable hydraulic conductivity However the following composition range percentage w w provides a useful guide for selecting an appropriate material Biofiltration Filter Media Guidelines Version 3 01 Prepared by the Facility for Advancing Water Biofiltration FAWB June 2009 FAWB Facility for Advancing Water Biofiltration Clay amp Silt lt 3 lt 0 05 mm Very Fine Sand 5 30 0 05 0 15 mm Fine Sand 10 30 0 15 0 25 mm Medium to Coarse Sand 40 60 0 25 1 0 mm Coarse Sand 7 10 1 0 2 0 mm Fine Gravel lt 3 2 0 3 4 mm Clay and silt are important for water retention and sorption of dissolved pollutants however they substantially reduce the hydraulic conductivity of the filter media This size frac
62. ng the occasional water quality sample is required but where continuous flow and water quality monitoring is not feasible From a practical viewpoint this approach is limited to small scale systems as the volume of stormwater required to evaluate large scale systems is too onerous This approach is also limited to sites where the outlet can be easily accessed in order to measure flow and collect water quality samples 2 RAIN EVENT SIMULATION The hydrologic and treatment performance of biofiltration systems can be assessed by simulating a rain event A pre determined volume of semi synthetic water usually equivalent to that of the design storm is prepared and delivered to the biofiltration system Normally this is done via a tanker truck and a mixing tank The outflow rate is measured and water quality samples are collected at regular intervals until outflow ceases Simulating a rain event is a full day exercise and initially requires a minimum number of four people the busiest stage is preparing and delivering the semi synthetic stormwater to the biofilter Once this stage has finished two people can manage the flow monitoring and water quality sample collection at the outflow Caution Appropriate safety protocols and precautions should be followed For example if the biofiltration system to be monitored is beside a road traffic control may be required While the risk of microbiological and virological hazards in stormwater is likely to be l
63. not be included in monitoring points Figure 1 Spatially distributed monitoring points 2 2 Apparatus The following is required e 100 mm diameter PVC rings with a height of at least 220 mm the bottom edge of the ring should be bevelled and the inside of the ring should be marked to indicate 50 mm and 150 mm above the filter media surface Figure 2 e AOL water e 100 mL 250 mL and 1000 mL measuring cylinders e Stopwatch e Thermometer e Measuring tape e Spirit level FAWB gt Facility for Advancing Water Biofiltration e Hammer e Block of wood approximately 200 x 200 mm 150 mm water level mark inside ring gt eee 50 mm water level mark inside ring gt see VA Me f 50 mm a K A Ey gt 4 gt Aa Ea 7 J da Taste w Se ET RE y pe 2 an u far i iagram of single ring infiltrometer 2 3 Procedure a Carefully scrape away any surface covering eg mulch gravel leaves without disturbing the soil filter media surface Figure 3b b Place the ring on the surface of the soil Figure 3c and then place the block of wood on top of the ring Gently tap with the hammer to drive the ring 50 mm into the filter media Figure 3d Use the spirit level to check that the ring is level Note It is essential that this the ring is driven in slowly and carefully to minimise disturbance of the filter media profile c Record the initial wate
64. ntial that data is checked for errors prior to evaluating results Possible problems include noise missing values outliers However outliers should not be removed without reason or justification 3 1 Pollutant load calculations Pollutant loads can be calculated by combining the flow and water quality data in VinCin where lin inflow load mg Vin total inflow volume L Cin inflow pollutant concentration mg L N out z DV ou rom i 1 where lout outflow load mg Viout volume between samples i and i 1 Ciout pollutant concentration at sampling interval i N total number of samples taken during simulation FAWB gt f al ty for Advant ing Water Biofiltration The load reduction is simply the difference between the inflow and outflow load expressed as a percentage of the inflow load 3 2 Performance targets number of state territories regions and municipalities stipulate performance targets for WSUD which often include biofiltration systems e g Clause 56 07 of the Victoria Planning Provisions prescribes target pollutant load reductions of 80 45 and 45 for TSS TN and TP respectively Where these exist monitoring data should be compared against these targets In the absence of stipulated performance targets outflow pollutant concentrations could be compared to the ANZECC Guidelines for Fresh and Marine Water Quality these guidelines provide water quality targets for protection of aq
65. of particulate phosphorus sourced from the slurry and FRP Caution Aquire and observe the Material Safety Data Sheets MSDS for each chemical that is used and follow appropriate protocols for safe handling and storage of chemicals 3 5 Preparation of stormwater Sections 3 5 1 3 5 3 describe the calculations required to determine to final volumes The spreadsheet Practice Note 2 Preparation of semi synthetic stormwater dosing calculations xis available at http www monash edu au fawb products index html can also be used to calculate the required mass of chemicals and slurry needed to prepare the semi synthetic stormwater 3 5 1 Dechlorinated water Mains water generally contains residual chlorine which should be neutralised with sodium thiosulphate Na S 03 prior to preparing the semi synthetic stormwater to avoid it having an effect 5 FAWB gt Facility for Advancing Water Biofiltration on the biological community in the biofilter The amount of sodium thiosulphate to add 0 1 g 100 L water 3 5 2 Amount of slurry to add The amount of slurry to add is calculated using Equation 2 _ TSSxv C S V Equation 2 S where v volume slurry L TSS target TSS concentration mg L Vs volume semi synethic stormwater L c sediment concentration in slurry mg L 3 5 3 Mass of chemicals to add The amount of chemical to add is calculated by substracting the concentration achieved by adding
66. onally high loads can cause the filter media within a biofiltration system to become clogged or blocked Blockage may occur as a result of the accumulation of fine sediment on the surface this can sometimes be manually removed Accumulation of fine sediment may also occur in a layer deeper within the filter media usually resulting in the need to remove and replace the filter media To protect the filter media while construction activities are occurring in the catchment at least one of the following precautions should be taken 1 Keep the biofiltration system off line during this period to prevent any stormwater entering Note adequate alternative sediment control measures must also be installed during construction to prevent heavy sediment loads being discharged directly to the stormwater system while the biofiltration system is off line 2 Delay final landscaping and protect the system by covering the entire biofiltration surface with geotextile and turf or gravel if desired for aesthetic purposes as shown in Figure 2 left or 3 Temporarily partition the biofiltration system creating a sacrificial sediment forebay This allows the vegetation to establish in the rest of the system while the sacrificial sediment forebay at the inlet is protected using textile and turf as described above and shown in Figure 2 right This approach is best suited when the overflow pit is located close to the inlet zone LT ys OU Fi
67. ote camera eg CCTV inspection of pipelines for blockage and structural integrity could be useful Frequency 6 MONTHLY AFTER RAIN Ensure inflow areas and grates over pits are clear of litter and debris and in good and safe condition A blocked grate would cause nuisance flooding Inspect for dislodged or damaged pit covers and ensure general structural integrity Remove sediment from pits and entry sites etc likely to be an irregular occurrence in mature catchment Frequency MONTHLY AND OCCASIONALLY AFTER RAIN 4 2 4 OTHER ROUTINE TASKS Inspection after rainfall Occasionally observe biofiltration system after a rainfall event to check infiltration Identify signs of poor drainage extended ponding on the filter media surface If poor drainage is identified check land use and assess whether it has altered from the design capacity eg unusually high sediment loads may require installation of a sediment forebay Frequency TWICE A YEAR AFTER RAIN Biofiltration System Maintenance Plan EXAMPLE 8 FAWB gt Facility for Advanc ng Water Biofiltration 4 2 5 FORM REGULAR INSPECTION amp MAINTENANCE Location Raingarden Tree Pit Site Visit Date Site Visit By Routine Inspection Complete section 1 below Purpose of the Site Visit Routine Maintenance a Complete sections 1 and 2 below NOTE Where maintenance is required yes in Section 2 details should be recorded in the
68. ow gloves should be worn Personnel should also have received necessary vaccinations consult a general practitioner or health advisor for further information FAWB gt f al ty for Advant ing Water Biofiltration Note A rain event simulation cannot be carried out in wet weather as any unquantified inflows will interfere with mass balance calculations with respect to runoff volumes and pollutant loads Further there must also be no residual outflow from a previous rain event The simulation should be carried out on a day when it is not predicted to rain before outflows from the simulation cease i e at least 24 hours after the beginning of the simulation and when there is no outflow from an existing event 2 1 Determination of rain event simulation volume In general a rain event simulation should be based on the design storm for that biofiltration system as this will enable evaluation of the upper performance limit For example if a biofiltration system was designed to treat up to a 15 minute rain event with an average recurrence interval ARI of three months the simulation volume should be equivalent to the volume of runoff produced during this rain event and over a time as close as possible to the design storm duration see further commentary on this in Section 2 5 2 2 Determination of water quality sampling intervals Outflow concentrations of some pollutants have been shown to vary dramatically with flow rate or ti
69. pport healthy plant growth In order to comply with both this and the TN and PO content requirements a low nutrient organic matter will be required iv pH as specified for natural soils and soil blends 5 5 7 5 pH 1 5 in water v Electrical Conductivity EC as specified for natural soils and soil blends lt 1 2 dS m Optional testing vi Dispersibility this should be carried out where it is suspected that the soil may be susceptible to structural collapse If in doubt then this testing should be undertaken Potential filter media should generally be assessed by a horticulturalist to ensure that they are capable of supporting a healthy vegetation community This assessment should take into Biofiltration Filter Media Guidelines Version 3 01 Prepared by the Facility for Advancing Water Biofiltration FAWB June 2009 FAWB Facility for Advancing Water Biofiltration consideration delivery of nutrients to the system by stormwater Any component or soil found to contain high levels of salt as determined by EC measurements high levels of clay or silt particles exceeding the particle size limits set above or any other extremes which may be considered retardant to plant growth should be rejected 3 ENGINEERED FILTER MEDIA Where there is not a locally available soil based material that complies with the properties outlined in Sections 2 1 2 3 it is possible to construct an appropriate
70. r non zero flows by using the Flow Based Sub Sample Bounds on the context sensitive menu of the treatment node FAWB gt Facility for Advancing Water Biofiltration SS Cumulative Frequency Graph Flow Based Sub Sample n gt pa BE Select Flow Thresholds ET J Lower Flow Threshold 0 000 cubic metres sec I Upper Flow Threshold cubic metres ser 100 Cumulative frequency distribution of all flow data for quiding your selection of flow thresholds Ee o ui Q ef del der el Cumulative Frequency hv En o 1 0 20 Flow cubic metres per second K X Cancel Left click and drag to zoom the graph right click and drag to scroll Ai Evaluating runoff frequency Evaluation of the runoff frequency objective with MUSIC v3 0 requires the export of data into Excel for subsequent analysis There are two basic components to the modelling 1 Determining the pre development runoff frequency and 2 Modelling the post development runoff frequency The modelling must be done using a 6 minute timestep The model results are then exported at daily timestep to Excel to calculate the daily runoff frequency Modelling the pre development runoff frequency Step 1 Select or create the appropriate climate template Select a 6 minute timestep climate template for one or more years model should either use a single year which has been assessed as being representative of long term
71. r stormwater Instead of ponding on the surface of the raingarden the holes left behind after the stakes are removed allow water to bypass the filter media and drain directly into the drainage layer at the base of the cell effectively bypassing any pollutant removal processes Biofiltration System Maintenance Plan EXAMPLE 6 FAWB gt Facility for Advancing Water Biofiltration 4 LONG TERM MAINTENANCE TASKS 4 1 Schedule of visits 4 1 1 Schedule of Site Visits Regular Inspection amp Maintenance Inspection Regular inspection and maintenance should be carried out to ensure the system functions as designed It is recommended that these checks be undertaken on a three monthly basis during the initial period of operating the system A less frequent schedule might be determined after the system has established Maintenance 4 2 Tasks The scope of maintenance tasks should include verifying the function and condition of the following elements Filter media Horticultural Drainage infrastructure Other routine tasks 14 2 1 FILTER MEDIA TASKS Sediment Remove sediment build up from forebays and other pre treatment measures in deposition biofiltration systems and from the surface of biofiltration street trees Frequency 3 MONTHLY AFTER RAIN Holes or scour Infill any holes in the filter media Check for erosion or scour and repair provide energy dissipation e g rocks and pebbles at in
72. r temperature d Fill the 1000 mL measuring cylinder e Using a different pouring apparatus slowly fill the ring to a ponding depth of 50 mm taking care to minimise disturbance of the soil surface Figure 3f Start the stopwatch when the water level reaches 50 mm f Using the 1000 mL measuring cylinder maintain the water level at 50 mm Figure 3g After 30 seconds record the volume poured g Maintain the water level at 50 mm recording the time interval and volume required to do so Note The time interval between recordings will be determined by the infiltration capacity of the filter media For fast draining media the time interval should not be greater than one minute however for slow draining media the time between recordings may be up to five minutes FAWB gt f al ty for Advant ing Water Biofiltration Note The smallest measuring cylinder that can pour the volume required to maintain a constant water level for the measured time interval should be used for greater accuracy For example if the volume poured over one minute is 750 mL then the 1000 mL measuring cylinder should be used Similarly if the volume poured is 50 mL then the 100 mL measuring cylinder should be used h Continue to repeat Step f until the infiltration rate is steady i e the volume poured per time interval remains constant for at least 30 minutes i Fill the ring to a ponding depth of 150 mm Figure 3h Restart the stopwatch Repe
73. require filtering should be filtered as soon as possible preferably immediately and samples that require refrigeration should be stored on ice Note If the semi synthetic stormwater is prepared in batches water quality samples should be collected from each batch and equal volumes from each batch combined for an average inflow concentration d Continue stirring open tap to allow semi synthetic stormwater to flow into biofilter start one stopwatch Note This stopwatch is the timer for the whole simulation and should not be stopped until the final flow and water quality measurements are taken e If preparing semi synthetic stormwater in batches begin preparing next batch as soon as the tank is empty Repeat Steps b d except for starting the stopwatch until all the semi synthetic stormwater has been delivered to the biofilter Note It is not possible to replicate a typical hydrograph using this approach however the aim is to deliver the entire volume in the same timeframe as the design storm For example for a 15 minute design storm the stormwater should be prepared and delivered to the biofilter in approximately 25 minutes allowing for some flow attenuation in the catchment f Check the outlet at regular intervals At the first appearance of flow measure the flow rate using a bucket and the other stopwatch and collect a water quality sample g Measure the flow rate at two minute intervals Enter this data into a spreadsheet
74. system FAWB gt Facility for Advancing Water Biofiltration There are a number of maintenance activities that need to be carried out to ensure effective long term function of biofiltration systems Table 1 provides example illustrations of maintenance issues while Table 2 outlines inspection tasks recommended frequencies and associated maintenance actions Table 1 Examples of issues requiring maintenance Build up of fine sediments on the surface of the filter media reduces surface inflow controls provided Holes erosion and scour should be repaired and or augmented porosity and treatment capacity unsightly and can hinder flow paths and organic litter build up is infiltration unsightly and can hinder flow paths and organic litter build up is infiltration Anthropogenic and Anthropogenic and og 2 o C O ow O wv c O lt SO o 3 m E re O lt 52 o O O o amp a NH L vu L O O oa q O L O SI fe 42 c O 42 O c gt q sign of too much or too little water or of poor filter Vegetation die off can be a function Weeds are unsightly and reduce treatment capacity Blocked overflow grates can result in nuisance flooding can set too low reduces the extended detention storage and treatment reduces the extended detention storage and treatment capacity Overflow levels that are capacity Overfilling of fil
75. ters FAWB Mit ou MAINTENANCE REQUIREMENTS FOR BIOFILTRATION SYSTEMS Table 2 Inspection and maintenance tasks for biofiltration systems a Sommet MM A U Action FILTER MEDIA ss MEDIA Check for sediment deposition 3 BR after rain RS ard Hedin a na of inlets and filter media reduces treatment Remove sediment from inlets er i So Ee and other pre treatment measures and the capacity surface of biofiltration street trees Check for holes erosion or scour 3 monthly after rain Holes erosion and scour can be a sign of excessive inflow e Infill any holes repair erosion and scour velocities due to poor inflow control or inadequate e Provide augment energy dissipation e g rocks and pebbles at inlet provision for bypass of high flows e Reconfigure inlet to bypass high flows e Relocate inlet Inspect for the build up of oily or clayey 3 monthly after rain Reduced surface porosity reduces treatment capacity e Clear away any mulch on the surface and lightly rake over the surface of the filter sediment on the surface of the filter media media between plants Check for litter in and around treatment areas 3 monthly after rain Flow paths and infiltration through the filter media may be Remove both organic and anthropogenic litter hindered HORTICULTURAL A A Assess plants for disease or pest infection 3 monthly or as desired for en Treat or replace as necessary aesthetics Check plants for signs of stunted growth or 3 monthly or as desire
76. th Australia Hatt B E T D Fletcher and A Deletic 2008 Hydraulic and pollutant removal performance of fine media stormwater filtration systems Environmental Science amp Technology 42 7 2535 2541 Hatt B E T D Fletcher and A Deletic 2007 Stormwater reuse designing biofiltration systems for reliable treatment Water Science and Technology 55 4 201 209 Hatt B E T D Fletcher and A Deletic 2007 The effects of drying and wetting on pollutant removal by stormwater filters Novatech 2007 6th International Conference on Sustainable Techniques and Strategies in Urban Water Management Lyon France Hatt B E T D Fletcher and A Deletic 2007 Hydraulic and pollutant removal performance of stormwater filters under variable wetting and drying regimes Water Science 8 Technology 56 12 11 19 Vegetation Read J T D Fletcher P Wevill and A Deletic in press Plant traits that enhance pollutant removal from stormwater in biofiltration systems International Journal of Phytoremediation Read J T Wevill T D Fletcher and A Deletic 2008 Variation among plant species in pollutant removal from stormwater in biofiltration systems Water Research 42 4 5 893 902 Bratieres K T D Fletcher A Deletic and Y Zinger 2008 Optimisation of the treatment efficiency of biofilters results of a large scale laboratory study Water Research 42 14 3930 3940 FAWB gt Facility for Adva
77. the slurry from the target concentration and converting the difference to a mass Equation 3 Since the concentration is reported as mg L of the pollutant of interest e g Cu the calculation includes a conversion from the mass of that pollutant to the equivalent mass of the compound e g CuSO4 1 Mr pollutantof interest m dosing compound c Cow X Va X Mr dosing compound Equation 3 where m dosing compound mass of dosing compound mg C target pollutant concentration mg L Cow pollutant concentration achieved by slurry water mix mg L Vs volume semi synthetic stormwater mg L Mr pollutant of interest molecular mass of pollutant of interest g mol Mr dosing compound molecular mass of dosing compound g mol For example the target concentration for Cu is 0 05 mg L however a slurry prepared from sediment Wetland A and mixed with water to the target TSS concentration only has a Cu concentration of 0 01 mg L Therefore the concentration needs to be increased by 0 04 mg L The molecular mass of Cu is 63 55 g mol while that of CuSO is 159 62 g mol To prepare 600 L of semi synthetic stormwater that meets the target Cu concentration 0 06 g of CuSO needs to be added to the slurry water mix FAWB gt Facility for Advancing Water Biofiltration m CuSO 0 05 0 01 x600x nE 60mg 0 06g 159 62 3 5 4 Mixing the semi synthetic water The water slurry and chemicals as required shou
78. tion also influences the structural stability of the material through migration of particles to block small pores and or slump It is essential that the total clay and silt mix is less than 3 w w to reduce the likelihood of structural collapse of such soils The filter media should be well graded i e it should have all particle size ranges present from the 0 075 mm to the 4 75 mm sieve as defined by AS1289 3 6 1 1995 There should be no gap in the particle size grading and the composition should not be dominated by a small particle size range This is important for preventing structural collapse due to particle migration 2 3 Soil Based Filter Media Properties The following specifications are based on results of extensive treatment performance testing conducted by FAWB as well as recommendations made by AS4419 2003 Soils for Landscaping and Garden Use Filter media must be tested for the following media that do not meet these specifications should be rejected or amended i Total Nitrogen TN Content lt 1000 mg kg ii Orthophosphate PO Content lt 80 mg kg Soils with total phosphorus concentrations gt 100 mg kg should be tested for potential leaching Where plants with moderate phosphorus sensitivity are to be used total phosphorus concentrations should be lt 20 mg kg iii Organic Matter Content at least 3 w w An organic content lower than 3 is likely to have too low a water holding capacity to su
79. ty parameters Australian New Zealand Standard 1998 Pollutant Container Filter Preservation Total Suspended Solids plastic bottle general washed n a refrigerate Total Nitrogen Total Phosphorus plastic bottle general washed n a refrigerate or freeze Nutrient species plastic bottle general washed 0 2 um filter on site 0 45 e Dissolved Organic Nitrogen um cellulose e Nitrate Nitrite acetate membrane e Ammonia filter and e Filterable Reactive Phosphorus refrigerate or freeze Metals plastic bottle acid washed n a acidify with nitric acid to pH 1 to 2 FAWB gt f al ty for Advant ing Water Biofiltration 2 5 Procedure a Place tank just upstream of the inlet to the biofiltration system b Prepare semi synthetic stormwater in tank continuously stirring Note Depending on the size of the tank it may not be possible to prepare the entire volume of semi synthetic stormwater required in one batch If this is the case it is entirely fine to prepare the stormwater in batches however the total number of batches should be minimised to reduce variability and maximise repeatability of the experiment c Collect water quality samples from the tank into the appropriate containers process and store as required Note To avoid sample contamination rinse sample collection vessels and bottles with a small amount of sample before filling and ensure hands do not contact the sample filters inside of bottles lids etc Samples that
80. uatic ecosystems the targets to use should be selected according to the location of the biofilter and the state of the receiving water e g slightly disturbed etc However the reality is that even using the best available technology biofiltration systems will not necessarily always be able to comply with these relatively strict guidelines The local authority may in this instance choose to rely on the national Load Reduction Targets provided in Chapter 7 of Australian Runoff Quality Wong 2006 Note Comparison of simulation results to performance should be treated with caution While this methodology enables a more detailed assessment than occasional grab samples it still provides only a snapshot and doesn t give detailed information about the overall performance of the biofiltration system for the whole range of rain events it is subjected to 4 CASE STUDY SATURN CRESCENT BRISBANE The methodology for simulating a rain event was originally developed in order to monitor the performance of a small biofiltration basin in McDowall Queensland Figure 1 This system was retrofitted into the streetscape of a residential area in 2006 to treat road and roof runoff The 20 m treatment area 2 of the impervious catchment area contains a 400 mm deep sandy loam filter media and a dense growth of Carex appressa and various Dianella species The system has a maximum ponding depth of 200 mm Two perforated 100 mm diameter PVC underdrain pip
81. ud 2007 Hydraulic performance of biofilters for stormwater management first lessons from both laboratory and field studies Water Science and Technology 56 10 93 100 Standards Australia 1995 AS1289 3 6 1 1995 Methods of testing soils for engineering purposes Soil classification tests Determination of the particle size distribution of a soil Standard method of analysis by sieving Sydney Australia Standards Australia International Ltd Standards Australia 2003 AS4419 2003 Soils for landscaping and garden use Sydney Australia Standards Australia International Ltd VicRoads 2004 Drainage of Subsurface Water from Roads Technical Bulletin No 32 Available at http webapps vicroads vic gov au vrne vrbscat nsf Water by Design 2009 Construction and Estabhlishment Guidelines Swales Bioretention Systems and Wetlands South East Queensland Healthy Waterways Partnership Brisbane Biofiltration Filter Media Guidelines Version 3 01 Prepared by the Facility for Advancing Water Biofiltration FAWB June 2009 FAWB DH CC error APPENDIX A Figure A 1 illustrates the change in hydraulic conductivity during the establishment phase of a Melbourne biofiltration system containing a sandy loam filter media The hydraulic conductivity initially declines as the filter media is compacted under hydraulic loading but recovers back to the design value as indicated by the dashed horizontal line as plant growth and increas
82. ws should not be more than 15 days greater than for the pre development case for the example below it is 12 days ie 8 12 20 ES Microsoft Excel Flow frequency calculation sheet 3 Oj x Ed File Edit wiew Insert Format Tools Data Window Help Adobe PDF Le 2 D GHALISSA 71 19 z 21 M 10 O iii uu Y Y 03 Reply with Changes End Review er gt D6 M f COUNTIF B2 B366 0 1 01 1959 0 2 01 1959 0 3 01 1959 0 Runoff frequency days yr COUNTIF B2 B366 lt gt 0 4 01 1959 0 00097466 COUNTIF B2 B366 lt gt 0 5 01 1959 0 00134462 1 6 01 1959 0 7101 1959 0 00101454 6 01 1959 9 01 1959 10 01 1959 11 01 1959 12 01 1959 13 01 1959 14 01 1959 15 01 1959 16 01 1959 17 01 1959 18 01 1959 19 01 1959 20 01 1959 21 01 1959 22 01 1959 VE gt D Tritial runoff depth calc examp Fi 1 year calc 4 gt Drawy e AutoShapesy N OO dir 8 dl O Zv Av E Ready Days without runoff 0000000000000 o The effect of evapotranspiration in biofiltration systems MUSIC v3 does not account for the effect of evapotranspiration within a biofiltration system rain garden even through recent research has shown that it can result in a reduction of mean annual flow by about 30 Hatt et al 2009 It is hoped that version 4 0 of MUSIC will address this issue FAWB DDC water Bioitration APPENDIXC GUIDELINES FOR FILTER MEDIA IN
83. yer material Note The perforations in the underdrain pipes should be small enough that the drainage layer cannot fall into the pipes A useful guide is to check to that the D drainage layer is greater than the pipe perforation diameter Geotextile fabrics are not recommended for use in biofiltration systems due to the risk of clogging An open weave shade cloth can be placed between the transition layer and the drainage layer to help reduce the downward migration of smaller particles if required however this should only be adopted where there is insufficient depth for transition and drainage layers 6 INSTALLATION It is recommended that filter media be lightly compacted during installation to prevent migration of fine particles In small systems a single pass with a vibrating plate should be used to compact the filter media while in large systems a single pass with roller machinery e g a drum lawn roller should be performed Under no circumstance should heavy compaction or multiple passes be made Filter media should be installed in two lifts unless the depth is less than 500 mm Biofiltration Filter Media Guidelines Version 3 01 Prepared by the Facility for Advancing Water Biofiltration FAWB June 2009 FAWB Facility for Advancing Water Biofiltration 7 FIELD TESTING It is recommended that field testing of hydraulic conductivity be carried out at least twice 1 one month following commencement of operation

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