Legacy Way Tunnel. Groundwater Level Monitoring (November 2017) Groundwater Level Monitoring Transurban Limited. 17-Dec Doc No. 001.

Transcription

1 roundwater evel onitoring ransurban imited 17-ec-2017 oc o. 001 egacy ay unnel roundwater evel onitoring (ovember 2017) 17-ec-2017 Prepared for ransurban imited :

2 roundwater evel onitoring egacy ay unnel egacy ay unnel roundwater evel onitoring (ovember 2017) lient: ransurban imited : Prepared by ustralia Pty td evel 8, 540 ickham treet, P ox 1307, Fortitude Valley Q 4006, ustralia F ec-2017 Job o.: in ustralia and ew Zealand is certified to I9001, I14001 /Z4801 and ustralia Pty td (). ll rights reserved. has prepared this document for the sole use of the lient and for a specific purpose, each as expressly stated in the document. o other party should rely on this document without the prior written consent of. undertakes no duty, nor accepts any responsibility, to any third party who may rely upon or use this document. his document has been prepared based on the lient s description of its requirements and s experience, having regard to assumptions that can reasonably be expected to make in accordance with sound professional principles. may also have relied upon information provided by the lient and other third parties to prepare this document, some of which may not have been verified. ubject to the above conditions, this document may be transmitted, reproduced or disseminated only in its entirety. 17-ec-2017 Prepared for ransurban imited :

3 roundwater evel onitoring egacy ay unnel Quality Information ocument egacy ay unnel ef ate Prepared by eviewed by 17-ec-2017 r ony Jong ark tewart evision istory ev evision ate etails ame/position uthorised ignature 1 17-ec-2017 FI r ony Jong ssociate eochemist 17-ec-2017 Prepared for ransurban imited :

4 roundwater evel onitoring egacy ay unnel able of ontents 1.0 Introduction xisting environment opography urface drainage ainfall eology roundwater roundwater level monitoring tatic groundwater levels roundwater level logger results onclusions and ecommendations tandard imitations 10 ppendix anual ater evel easurements Field ecords ist of ables able 1 ummary of rainfall in proximity to the egacy ay unnel 2 able 2 ummary of groundwater level monitoring locations 4 able 3 ummary of manual groundwater level/elevation measurements (ugust- ctober 2017) 6 ist of Figures Figure 1 egacy ay unnel groundwater level monitoring locations 3 Figure 2 roundwater elevations within alluvium along the main egacy ay unnel alignment 7 Figure 3 roundwater elevations within bedrock along the main egacy ay unnel alignment 7 Figure 4 roundwater elevations long the western extent of egacy ay unnel alignment 8 Figure 5 roundwater elevations long the eastern extent of egacy ay unnel alignment 8 17-ec-2017 Prepared for ransurban imited :

5 roundwater evel onitoring egacy ay unnel Introduction onstruction on egacy ay unnel started in pril 2011 and the tunnel opened to traffic on 25 June ransurban imited (ransurban) is, as part of the oordinator eneral's conditions for the peration and aintenance phase of the egacy ay, required to monitor groundwater levels in existing monitoring bores along the tunnel alignment. onitoring of groundwater levels is required for 5 years post-construction. roundwater inflow volumes into the tunnel is monitored to ensure compliance with tunnel specifications and to inform the development of reasonable and practical mitigation measures in the event that significant groundwater drawdown or migration of potential contaminants occurs within the surrounding area. ransurban commissioned ustralia Pty td () to assess the latest groundwater level data obtained on a monthly monitoring program from existing monitoring bores along the tunnel alignment. he objective of the groundwater level monitoring is to assess changes to groundwater levels and identify any ongoing drawdown in the surrounding area as a result of inflow to the tunnel, including the potential for inflow to occur from the risbane iver. 1.1 xisting environment he egacy ay unnel is situated in the inner western suburbs of risbane and includes the suburbs of oowong, uchenflower, ilton, Paddington, ed ill, elvin rove and erston (see Figure 1). 1.2 opography he natural topography of the surrounding area is characterised by a series of steep ridges and spurs dissected by linear valleys. he natural ground surface elevations range from approximately 70 metres above ustralian eight atum (m) near the intersection of usgrave oad and elvin rove oad (near the eastern entrance) and 50 m near the intersection of Frederick treet and irdwood errace (near the western entrance). he lowest point is mid-tunnel (<5 m). long the tunnel alignment, the natural ground surfaces rise toward the west and northwest and fall toward the east and southeast (i.e. along the risbane iver). 1.3 urface drainage he egacy ay unnel is located within two sub-basins, informally referred to as the risbane and noggera reek sub-catchments. ost of the tunnel alignment is located within the risbane subbasin, with the eastern most extent of the tunnel located within the noggera reek sub-basin. hese sub-catchment areas are drained by a number of small creeks that empty into the risbane iver. he sub-basins are part of the ower risbane iver atchment that hosts a number of surface water tributaries, including ellbowrie, reakfast, ulimba, ubberla and noggera reeks. ithin the immediate vicinity of the tunnel, most surface waters are drained via oowong reek and noggera reek. 1.4 ainfall he risbane area is characterised by a sub-tropical climate. ainfall occurs predominantly throughout the summer months (ecember to February). he mean annual rainfall in proximity to the tunnel is summarised in able ec-2017 Prepared for ransurban imited :

6 roundwater evel onitoring egacy ay unnel 2 able 1 ummary of rainfall in proximity to the egacy ay unnel ource ocation tation Period ureau of eteorology () 1.5 eology risbane oowong owls lub (ept) risbane otanic ardens t oot-ha ean nnual ainfall (mm) he geology underlying the egacy ay unnel and adjacent areas consists of two low grade metamorphic rock units, namely the unya Phyllite and the eranleigh-fernvale eds. he unya Phyllite occupies the area along the alignment up to approximately usgrave oad at the ormanby Fiveways. Further east, the alignment lies within the eranleigh-fernvale eds. he unya Phyllite formation consists of phyllite, minor arenites and basic volcanics regionally metamorphosed to greenschist grade. he phyllites are usually dark blue to black and consist principally of quartz, albite, muscovite and chlorite. he eranleigh-fernvale eds may be up to 7000 metres (m) thick and overlies the unya Phyllite. he eranleigh-fernvale eds includes shale, chert, jasper, feldspathic and lithic arenite, conglomerate and basic volcanics. ypical arenites consist of sericite, chlorite, quartz and epidote with accessory zircon. ear the each end of the tunnel, minor surficial deposits of Quaternary-aged alluvium are present consisting of undifferentiated gravel, sand, silt, mud and clay. ased on exposed road cuttings, soils within the vicinity of the tunnel are very thin and largely derived from the unya Phyllite formation. 1.6 roundwater roundwater occurrence is associated with the following hydrostratigraphic units: unya Phyllite eranleigh-fernvale eds Unconsolidated alluvium sediments. epth to groundwater is generally between 3 metres below ground level (m) and 10 m within the unya Phyllite and eranleigh-fernvale beds. epths to water table of greater than 10 metres have been found at locations of elevated topography (e.g. at 2-06 and 2-14). roundwater levels within the basement rock aquifers are likely to respond rapidly to rainfall recharge downslope of topographically elevated areas and where deep drainage from water supply infrastructure (i.e. mains, stormwater) and drainage lines occurs. roundwater levels found within the alluvium are relatively shallow (< 9 m). roundwater recharge to these areas is likely to be relatively rapid following rainfall events (unconfined aquifers) and is expected to gradually decline following cessation due to evapotranspiration and limited effective storage. 2.0 roundwater level monitoring roundwater level data is currently collected by aboratory, on behalf ransurban, on a monthly basis. has used this data (as provided) to generate groundwater hydrographs, which are used to assess the temporal and spatial trends and relationships between rainfall and local groundwater systems within the alluvium and bedrock. he data was derived from 20 automated groundwater level loggers (olinst) and manual water level measurements (i.e. static groundwater levels). he groundwater level monitoring locations are summarised in able 2 and shown in Figure ec-2017 Prepared for ransurban imited :

7 I U IF I P I I U U V U I F PP I U X U PI X UI PI V I P U U X P U V I F I I I ZI Z VI F F I I U V U F U X U onitoring ore ocations roundwater evels PJ I J P I V U I I VI I VI I U VUU ase ata: (c) 2017 IP Imagery,, tate of Qld I I U ata sources: I I U I I F I FI U QU I I I U I QUI V V U I V I V I FI P I F I P I XP F U U PI F U U I I I P IFI V P I I I I II I FF P F F PI JU I P V IV I IV I onitoring ore ocation I U I P asement IV F I :\us_ines\i\eam - &\1_usiness_evelopment\Projectsithoutumber_2017\ \02_Xs\ _F1_3_onitoringoreocations.mxd I I P F U Q I P I U U U UU P J Volumetric adastral oundary I I J I I I IFF J etres 1:12,500 (when printed at 3) P 620 ase adastral oundary V I I U QU I 0 I I P I JU I I U I I IV PI does not warrant the accuracy or completeness of information displayed in this map and any person using it does so at their own risk. shall bear no responsibility or liability for any errors, faults, defects, or omissions in the information. U P ZI I P V U J X VI V FI U P X IPP I P I F oordinate ystem: 1994 Zone 56 Projection: ransverse ercator I I I V V UX U P X I V P I I V P VI U I I I I P I P I V I I I I UP I V P VI U I Filename: U IZ I 3-16 I P I V I V U F J 3-05 P U 108 P P U I 2-12 VI 320 U P U U UP P 4-10 F I I VI V U F F 313 U U I 312 I I V U 4-5 U IX I U 4-6 IZ F P U U V I P V XF 4-2 U I P I I IP I U PI U I P U F U IV JUU U V U V FI U J I P I I I Z IV U V Z P V U P V I P U U V I I U V U U IZZI I I P V U I VI P I P I I P V U I V I FFI I P I F VI: 1 IFI - 23/11/2017 Figure 1 3 size

8 roundwater evel onitoring egacy ay unnel 4 he level loggers measure the total pressure acting on a transducer at their zero point/sensor. he total pressure is a combination of the column of water lying above the logger pressure sensor (i.e. height of water column) and the atmospheric (barometric) pressure acting on the water surface. he level logger data is barometrically and temperature compensated to obtain true height of water column measurements. ll groundwater level logger data was converted to groundwater elevations in m. here required, the deployment depth of the logger was assumed constant and calculated as the sum of the depth to water below a well casing (as measured by manual water level readings) and the compensated height of water column. he complete post-construction groundwater level data (from pril 2015 to July 2017) was not available at the time of reporting due to change in service providers and associated commercial matters related to project data hand-over. s such, the groundwater level data obtained during the ovember 2017 monitoring event were compared to manual water level readings (where possible) obtained during the construction phase. able 2 ummary of groundwater level monitoring locations lignment ocation ore I eological Unit est raffic Island, estern t oot-ha d, oowong ound about end, estern Freeway, oowong nzac park near bike track and creek, oowong lluvium lluvium emetery - bottom, oowong 108 emetery, oowong 320 horpe treet, oowong 2-12 irdwood ce, uchenflower 2-14 oad outside of civic video, osalie 309 aroona oad bus stop, osalie 311 lizabeth treet, osalie 312 pen ore and lluvium ain aroona oad across from school (next to 313), osalie 313 aroona oad across from school (next to 313), osalie 313 lluvium regory Park, osalie 4-10 lluvium llena t, Paddington 4-6 lluvium llena t, Paddington 4-5 regory Park, osalie 4-2 Upper lifton ce, ed ill 2-06 ower lifton ce, ed ill 2-09 ast Victoria park oad, elvin rove 221 Inner ity ypass ec-2017 Prepared for ransurban imited :

9 roundwater evel onitoring egacy ay unnel tatic groundwater levels anual groundwater level readings obtained from ovember 2017 are summarised in able 3. It is noted that groundwater level was not measured at groundwater monitoring bore 2-14 because it was not accessible on the day of sampling due to cars being parked over borehole. Field records of the manual water level measurements are provided in ppendix. 4.0 roundwater level logger results ydrographs of groundwater elevations against rainfall with time are shown Figure 2 to Figure 5. he rainfall data was based on the ureau of eteorology s risbane otanic ardens t oot-ha tation (040976) (able 1) roundwater bores monitoring the alluvial (4-10, 313 and 4-6) and basement rock (e.g. 108, 320, 2-06 and 2-09) aquifers along the tunnel alignment are shown in Figure 2 and Figure 3, respectively. he groundwater elevations within these areas are stable and consistent over the reported monitoring period with previous observations. otably, the groundwater elevations within the alluvium (313) and bedrock (313, 2-02 and 2-09) show increases in groundwater elevation in response to rainfall recharge and gradually declines (during periods due to limited effective storage within the alluvium). Predictive groundwater modelling completed for the construction phase (orthern ink, echnical eport 4, roundwater, June 2008) showed that groundwater level drawdown cone was expected to develop in the fractured bedrock aquifer approximately 100 metres in width either side of the tunnel alignment following one year of construction. he greatest drawdown was predicted to occur within the alluvium located in proximity to Fernberg oad (at the mid-point of the tunnel alignment). he post-construction monitoring data collected to date indicate that the groundwater elevations measured in monitoring bores located near the mid-point of the tunnel alignment (309, 311, 312, 313 and 313) have similar trends and range compared to values observed during the construction phase (-8.39 m to 2.22 m, m to 2.71 m, m to 2.17 m, and m to 1.68 m, respectively). he trend in groundwater elevations measured at the western extent of the tunnel at 2-02 (bedrock), 3-05 (alluvium) and 3-16 (alluvium) are consistent with previous monitoring events (Figure 4). he groundwater elevations respond to rainfall recharge downslope of topographically elevated areas (e.g. 2-02) and where surface water and drainage lines occurs (e.g. local creeks and ount oot-ha Quarry and risbane otanic arden ponds). roundwater level monitoring of the eastern portion of the tunnel shows that the groundwater elevations (at 221 and 222) have remained relatively constant since pril 2017 with no observed fluctuations due to rainfall recharge. decline in groundwater elevation (up to 2.76 m) was observed on 27 eptember 2017 at 222 (Figure 5); however, the rebound in groundwater elevation was rapid returning to levels consistent with those observed in July he measured groundwater elevation was within those observed between 26 July 2012 to 22 pril 2015 (15.36 m to m; n =42) during the construction phase. he post-construction monitoring data collected to date indicate that the inflow of saline water from the risbane iver into the aquifer and subsequently to the tunnel as a consequence of groundwater drawdown during the operation of the tunnel is unlikely to be occurring. he gradient of the potentiometric surface in the alluvium and fractured rock aquifer is likely to be towards the river due to a zone of slightly elevated groundwater between the tunnel and the risbane iver (e.g. as measured in 3-16, 4-10 and 2-12). 17-ec-2017 Prepared for ransurban imited :

10 lluvium lluvium & lluvium lluvium lluvium lluvium roundwater evel onitoring egacy ay unnel 6 able 3 ummary of manual groundwater level/elevation measurements (ovember 2017) lignment est ain ast ore I eological Unit (m) ovember 2017 ater evel (m) ater levation (m) m = metres ustralian eight atum m = metres below top of casing -- = not measured due to site accessibility constraints at the time of field work 17-ec-2017 Prepared for ransurban imited :

11 roundwater evel onitoring egacy ay unnel 7 Figure 2 roundwater elevations within alluvium along the main egacy ay unnel alignment Figure 3 roundwater elevations within bedrock along the main egacy ay unnel alignment 17-ec-2017 Prepared for ransurban imited :

12 roundwater evel onitoring egacy ay unnel 8 Figure 4 roundwater elevations long the western extent of egacy ay unnel alignment Figure 5 roundwater elevations long the eastern extent of egacy ay unnel alignment 17-ec-2017 Prepared for ransurban imited :

13 roundwater evel onitoring egacy ay unnel onclusions and ecommendations he temporal and spatial trends in groundwater elevations along the egacy ay unnel alignment, and relationships between rainfall and local groundwater systems within the alluvium and bedrock are consistent with historical observations. he inflow of saline water from the risbane iver into the aquifer and subsequently to the tunnel as a consequence of groundwater drawdown during the operation of the tunnel is unlikely to be occurring. s such, no mitigation measures are required at this point in time to minimise the extent of groundwater level drawdown in the surrounding area as a result of inflow to the tunnel. It is recommended that monitoring continue at all current sites to assess changes to groundwater levels and identify any ongoing drawdown the surrounding area and associated potential impacts. 17-ec-2017 Prepared for ransurban imited :

14 roundwater evel onitoring egacy ay unnel tandard imitations onsulting ervices (Z) imited () has prepared this report in accordance with the usual care and thoroughness of the consulting profession for the use of ransurban imited and only those third parties who have been authorised in writing by to rely on this eport. It is based on generally accepted practices and standards at the time it was prepared. o other warranty, expressed or implied, is made as to the professional advice included in this eport. It is prepared in accordance with the scope of work and for the purpose outlined in the contract dated 25 eptember 2017 (Purchase rder ). here this eport indicates that information has been provided to by third parties, has made no independent verification of this information except as expressly stated in the eport. assumes no liability for any inaccuracies in or omissions to that information. his eport was prepared between 07 ecember 2017 and 12 ecember 2017 and is based on the conditions encountered and information reviewed at the time of preparation. disclaims responsibility for any changes that may have occurred after this time. his eport should be read in full. o responsibility is accepted for use of any part of this report in any other context or for any other purpose or by third parties. his eport does not purport to give legal advice. egal advice can only be given by qualified legal practitioners. xcept as required by law, no third party may use or rely on this eport unless otherwise agreed by in writing. here such agreement is provided, will provide a letter of reliance to the agreed third party in the form required by. o the extent permitted by law, expressly disclaims and excludes liability for any loss, damage, cost or expenses suffered by any third party relating to or resulting from the use of, or reliance on, any information contained in this eport. does not admit that any action, liability or claim may exist or be available to any third party. xcept as specifically stated in this section, does not authorise the use of this eport by any third party. It is the responsibility of third parties to independently make inquiries or seek advice in relation to their particular requirements and proposed use of the site. ny estimates of potential costs which have been provided are presented as estimates only as at the date of the eport. ny cost estimates that have been provided may therefore vary from actual costs at the time of expenditure. 17-ec-2017 Prepared for ransurban imited :

15 roundwater evel onitoring egacy ay unnel ppendix anual ater evel easurements Field ecords 17-ec-2017 Prepared for ransurban imited :

16 P lient: Job ame: ichael oombes ransurban Queensland 7 randl treet oopers Plains Q 4113 egacy ay onthly roundwater evels ampled y: aboratory ampling ethod: rab ample atrix: queous atch umber: 17/10604 egistration ate: 21 ovember 2017 ate of eport: 29 ovember /10604/7: : not accessible on day of sampling due to car parked over borehole. P : 1. he results refer only to the samples tested. 2. ll sampling performed by aboratory is in accordance with In-house ethod F his document shall not be reproduced except in full, without written approval from aboratory. 4. ethod with * indicates accreditation does not cover the performance of this service. Page 1 of 2

17 lient: ransurban Queensland atch umber: 17/10604 Job ame: egacy ay onthly roundwater evels eport ate: 29/11/17 ethod est Units 17/10604/1 17/10604/2 17/10604/3 17/10604/4 17/10604/5 17/10604/6 17/10604/7 17/10604/8 17/10604/9 17/10604/ /11/ /11/ /11/ /11/ /11/ /11/ /11/ /11/ /11/ :20 07:12 08:40 08:02 08:12 07:03 04:15 04:25 04:52 ire - raffic ontrol omplete [] [] [] [] [] [] [] [] [] isc. * roundwater evel m [] ethod est Units 17/10604/11 17/10604/12 17/10604/13 17/10604/14 17/10604/15 17/10604/16 17/10604/17 17/10604/18 17/10604/19 17/10604/ /11/ /11/ /11/ /11/ /11/ /11/ /11/ /11/ /11/ /11/ :35 04:42 05:25 05:08 05:00 05:20 05:38 05:50 06:05 06:25 isc. * roundwater evel m [] - ot etected [] - ot equired [] - ot ested P : 1. he results refer only to the samples tested. 2. ll sampling performed by aboratory is in accordance with In-house ethod F his document shall not be reproduced except in full, without written approval from aboratory. 4. ethod with * indicates accreditation does not cover the performance of this service. Page 2 of 2