21676 - fts report - 64 grandview lane bowen mountain - … · 2017. 6. 14. · 21676 page 5...
TRANSCRIPT
C O N S U L T I N G C I V I L A N D S T R U C T U R A L E N G I N E E R SEmail: [email protected]: http://www.ftsaus.comOperation Centres:NSW: 12 Caribbean Place, Mt Colah NSW. 2079Mbl: 0431 201 421 (Danny) or 0431 125 906 (Janine)
QLD: 90 Jean Street, Woodridge Qld. 4114Mbl: 0466 970 683 (Troy)
21674 Page i
ENGINEERING REPORT
INFRASTRUCTURE DEVELOPMENT PLANNING REPORT
At:
64 GRANDVIEW LANE, BOWEN MOUNTAIN NSW 2753
For:
MISS DALE RAPEROF 56 GRANDVIEW LANDBOWEN MOUNTAIN
WITHOUT PREJUDICE
INFRASTRUCTURE DEVELOPMENT PLANNING REPORT 56 GRANDVIEW LANE, BOWEN MOUNTAIN NSW 2753Issue B – 11th December 2016
21676 Page 2 D:\DOCUMENTS\21676 - 56 Grandview Lane Bowen Mountain\DOCMNT\REPORT\21676 - FTS Report - 64 Grandview Lane Bowen Mountain - Engnieering Development Report-Issue B.docx
DOCUMENT CONTROL SHEET
FTS Reference No: 21676
Client: Miss Dale Raper
Site Address: 56 Grandview Lane, Bowen Mountain NSW 2753
Report Title: INFRASTRUCTURE DEVELOPMENT PLANNING REPORT
Synopsis: Inspect site from adjoining property and review development applications and approvals to provide opinion as to capacity of sewerage system to support the development upon the land
Conditions: Inspection @ 4pm on 2/12/16 - dry and hot with a light breeze.
Document ControlVersion Date Author ApprovedDraft Issue A
5 December 2016 D. Lee D. Lee
Issue B 11 December 2016 D. Lee D. Lee
Daniel LeeB.E. (Civil) M.B.A. MIE Aust. AIMM NPER 113806 RPEQ 7709Chartered Professional EngineerDirector
INFRASTRUCTURE DEVELOPMENT PLANNING REPORT 56 GRANDVIEW LANE, BOWEN MOUNTAIN NSW 2753Issue B – 11th December 2016
21676 Page 3 D:\DOCUMENTS\2167 - 56 Grandview Lane Bowen Mountain\DOCMNT\REPORT\21676 - FTS Report - 64 Grandview Lane Bowen Mountain - Engnieering Development Report-Issue B.docx
EXECUTIVE SUMMARYFTS has been retained to provide forensic engineering advice for the sewerage system and associated development infrastructure for the buildings constructed on 64 Grandview Lane Bowen Mountain. This report is provided “without prejudice” and is based on briefings and information provided by the client and industry standard including:
Consent conditionsInternal Council memorandaApplication information including forms and statements therein, and technical drawingsRelevant standards such as AS1547:2012 and guidelinesHawkesbury City Council’s LEP and DCPProfessional journals and manuals for the design of engineering infrastructure and site characterisationA site inspection and meetings with the clients and their other associated consultants.An ultimate building layout is proposed which has two/three kitchens areas, and up to 9 bedrooms plus study giving a capacity of 10 to 12 persons based on the usual allowance for persons being 1 per bedroom plus an additional person used by EPA guidelines per household. Existing approved layout consists of the original 3 bedrooms house and a non-habitable attached studio plus a separate non-habitable barn building. A subsequent approval appears to have been granted to convert the studio into a separate residence as a “dual occupancy”.The existing AWTS capacity is 10 persons with original design requirement of 1000 sqm LAA plus 1000 sqm reserve. (Site constraints assessment and soil testing with and risk assessment report as per AS1547 not provided for DA).
FTS has not had sufficient time to undertake a full site assessment for the onsite sewerage system but from the inspection on 2 December 2016 and based on a desktop assessment the following can be inferences can be made:
In short, when considered in the context for an on-site sewer management system (OSSMS) the development site is highly constrained. This is due to:
the steep slope on the west portion of the land limiting it use as a disposal area (even as a reserve)the extent for rock outcrops and shallow depth to rock typical of heath country in this terrain (classified and “Hawkesbury” in Soil Landscapes of Penrith)the proximity of a farm dam less than 25 m from the proposed land application disposal area (Hawkesbury City Council requirement is 40 m)available disposal areas reduced due to relocated water tank and AWTS tanks of about 60 sqm within the primary LAA disposal area
INFRASTRUCTURE DEVELOPMENT PLANNING REPORT 56 GRANDVIEW LANE, BOWEN MOUNTAIN NSW 2753Issue B – 11th December 2016
21676 Page 4 D:\DOCUMENTS\21676 - 56 Grandview Lane Bowen Mountain\DOCMNT\REPORT\21676 - FTS Report - 64 Grandview Lane Bowen Mountain - Engnieering Development Report-Issue B.docx
available disposal areas reduced further due to 96 sqm barn within the primary LAA disposal area
original sewage treatment system sized for a 10 person limit with 1000 sqm of primary LAA disposal area required and 1000 sqm reserve area. Available LAA area remaining from original primary LAA estimated to be only 624 sqmLAA soils gradually reduce in capacity to treat organisms over time and satisfactory performance requires a detailed soil sampling analysis and monitoring the changes over time to predict suitability for increasing the surface loading rate of the effluentThe existing house has 6 bedrooms (5 in original DA and a sixth added in the breezeway plus an additional kitchen area) and the new additions partially cover the reserve LAA.The barn and water tank slab is located on the primary LAA a per the original DA sewer plan.
The EPA states in the Environment & Health Protection Guidelines On-site Sewage Management for Single Households (1998):
“The performance of on-site systems is more variable than public systems, because they are operated by individual householders and service agents, and because performance and accountability requirements are less clearly defined. Existing on-site systems are failing to meet environment and health protection standards in many parts of NSW. The reasons suggested for system failures include initial planning and design faults, increasing wastewater loads, inadequate system maintenance and operator errors.
Amendments to local government regulations have clarified the responsibilities of householders and councils to ensure that on-site sewage management systems comply with performance standards and do not pose a risk to public health and the environment….
.….It is inadequate for service agents simply to report on the maintenance of treatment devices. Service agents should also be required to check land application areas and to confirm that site maintenance, buffer distances and access control requirements are being complied with.”
Regular service inspection reports should cover the full system, including household fixtures, plumbing, septic tanks, pumps, blowers, sensors, alarm systems, effluent storage systems, land application areas, biosolids management and risk management procedures
In accordance with the Councils Septic Safe Program, the site should be classed as a medium Risk due to the lack of soil cover and depth and requires a design report for the proper planning of the sewage treatment system.
Water balance calculations for 6 bedrooms using a monthly average dataset for Richmond RAAF based rainfalls which is 8 km away demonstrates that 570 sqm of LAA is required of at least 150 mm of good quality topsoil (Ref: AS1547). For 9 beds (10 persons) 950 sqm of LAA is required. For 12 persons as per the owners application requests 1140 sqm of LAA is
INFRASTRUCTURE DEVELOPMENT PLANNING REPORT 56 GRANDVIEW LANE, BOWEN MOUNTAIN NSW 2753Issue B – 11th December 2016
21676 Page 5 D:\DOCUMENTS\21676 - 56 Grandview Lane Bowen Mountain\DOCMNT\REPORT\21676 - FTS Report - 64 Grandview Lane Bowen Mountain - Engnieering Development Report-Issue B.docx
required. This assumes the subsoil is not rock. Rock outcrops change the requirement requiring more land to achieve the treatment targets for the effluent.
From the simple assessment undertaken the land is highly constrained and present a high risk, which would require a detailed on-site sewer and water management report under the Hawkesbury DCP. Such a report has not been made available and given the desktop analysis results it is unlikely the sewer system is achieving the desired health and ecological discharge standards. It is incumbent of Council to ensure such standards are adhered to by all land owners under various legislation both state and federal.
INFRASTRUCTURE DEVELOPMENT PLANNING REPORT 56 GRANDVIEW LANE, BOWEN MOUNTAIN NSW 2753Issue B – 11th December 2016
21676 Page 6 D:\DOCUMENTS\21676 - 56 Grandview Lane Bowen Mountain\DOCMNT\REPORT\21676 - FTS Report - 64 Grandview Lane Bowen Mountain - Engnieering Development Report-Issue B.docx
TABLE OF CONTENTSEXECUTIVE SUMMARY ............................................................................................ 3
TABLE OF CONTENTS.............................................................................................. 6
1 INTRODUCTION .............................................................................................. 7
2 OBSERVATIONS.............................................................................................. 8
2.1 SEWER LAA.................................................................................................. 8
2.2 BARN LOCATION ON PRIMARY LAA ........................................................12
2.3 RESERVE LAA............................................................................................13
2.4 NEARBY FARM DAM..................................................................................13
2.5 SEWER OPERATION .................................................................................14
3 CALCULATIONS ............................................................................................14
4 CONCLUSION................................................................................................15
APPENDICES...........................................................................................................16
INFRASTRUCTURE DEVELOPMENT PLANNING REPORT 56 GRANDVIEW LANE, BOWEN MOUNTAIN NSW 2753Issue B – 11th December 2016
21676 Page 7 D:\DOCUMENTS\21676 - 56 Grandview Lane Bowen Mountain\DOCMNT\REPORT\21676 - FTS Report - 64 Grandview Lane Bowen Mountain - Engnieering Development Report-Issue B.docx
1 INTRODUCTION Pursuant to a long standing dispute about the alleged changes that occurred during construction without notification or prior review by the Council, the purpose of this report is to provide forensic engineering advice for the sewerage system and associated development infrastructure for the buildings constructed on 64 Grandview Lane Bowen Mountain.
A number alleged of changes have occurred at the site which include:
Repositioning of the house slab without noticeRepositioning the AWTS tanks and 8.3 m diameter Water Tank within the front primary LAA for the sewerage systemConstruction of a large Barn close to the boundary and within the primary LAA for the sewerage system rather than close to the home on usable spaceChange of use from single Residence to a Dual Occupancy with addition of a second kitchen and extra bedroom within the carport/breezeway
A further application is now before Council seeking application for alterations and additionsfor at least 4 bedrooms + study of 2 stories in height on the high side of the site. This proposal is partly situated on the reserve LAA for the sewage treatment system.
FTS has undertaken a preliminary review of the requirements of the AWTS LAA requirements based on the current and proposed usage demands in accordance with AS1547 flows and provides comments accordingly.
INFRASTRUCTURE DEVELOPMENT PLANNING REPORT 56 GRANDVIEW LANE, BOWEN MOUNTAIN NSW 2753Issue B – 11th December 2016
21676 Page 8 D:\DOCUMENTS\21676 - 56 Grandview Lane Bowen Mountain\DOCMNT\REPORT\21676 - FTS Report - 64 Grandview Lane Bowen Mountain - Engnieering Development Report-Issue B.docx
2 OBSERVATIONSInspection of the clients’ property on 2 December 2016 support the typical soil profile (horizons A/B/C) of a Hawkesbury (ha) soil profile (refer appendix). However on the neighbouring site (No. 64) the site has been filled with imported sandstone as can be seen from the photos below. The compacted sandstone would be relatively impervious and upon further mineral weathering, leaching and aging will become more “clay like” at the granular level. Such material needs to be covered in a suitable topsoil to provide adequate tertiary treatment of the secondary sewage effluent from the AWTS.
2.1 SEWER LAA
It appears that the owner has determined that the LAA are to be located adjacent to the house as indicated by the lush lawn areas seen in the photos below. These areas are visible in Google Earth imagery and the areas are shown in the “white” polygons in the image below.
Photo 1 Irrigated lawns areas of 100 and 75 sqm
INFRASTRUCTURE DEVELOPMENT PLANNING REPORT 56 GRANDVIEW LANE, BOWEN MOUNTAIN NSW 2753Issue B – 11th December 2016
21676 Page 9 D:\DOCUMENTS\21676 - 56 Grandview Lane Bowen Mountain\DOCMNT\REPORT\21676 - FTS Report - 64 Grandview Lane Bowen Mountain - Engnieering Development Report-Issue B.docx
Photo 2 Irrigated lawn 1 of 100 sqm
Photo 3 Irrigated lawn 2 of 75 sqm
INFRASTRUCTURE DEVELOPMENT PLANNING REPORT 56 GRANDVIEW LANE, BOWEN MOUNTAIN NSW 2753Issue B – 11th December 2016
21676 Page 10D:\DOCUMENTS\21676 - 56 Grandview Lane Bowen Mountain\DOCMNT\REPORT\21676 - FTS Report - 64 Grandview Lane Bowen Mountain - Engnieering Development Report-Issue B.docx
Photo 4 Irrigated lawn 2 of 75 sqm (mid photo).Part of original primary LAA in foreground)
Photo 5 Original soil profile inspection hole (on neighbouring property No. 56)
INFRASTRUCTURE DEVELOPMENT PLANNING REPORT 56 GRANDVIEW LANE, BOWEN MOUNTAIN NSW 2753Issue B – 11th December 2016
21676 Page 11 D:\DOCUMENTS\21676 - 56 Grandview Lane Bowen Mountain\DOCMNT\REPORT\21676 - FTS Report - 64 Grandview Lane Bowen Mountain - Engnieering Development Report-Issue B.docx
Photo 6 Location of prime soil profile inspection hole (on neighbouring property No. 56). Other holes dug by client were also
inspected and most hit rock within 100 to 200 mm below surface)
INFRASTRUCTURE DEVELOPMENT PLANNING REPORT 56 GRANDVIEW LANE, BOWEN MOUNTAIN NSW 2753Issue B – 11th December 2016
21676 Page 12D:\DOCUMENTS\21676 - 56 Grandview Lane Bowen Mountain\DOCMNT\REPORT\21676 - FTS Report - 64 Grandview Lane Bowen Mountain - Engnieering Development Report-Issue B.docx
2.2 BARN LOCATION ON PRIMARY LAA
Photo 7 Barn situated on a sandstone cut zone (previously second primary LAA area).
Photo 8 RWT to Barn located on opposite side to approvedplans (unsure if barn was relocated to suit)
INFRASTRUCTURE DEVELOPMENT PLANNING REPORT 56 GRANDVIEW LANE, BOWEN MOUNTAIN NSW 2753Issue B – 11th December 2016
21676 Page 13D:\DOCUMENTS\21676 - 56 Grandview Lane Bowen Mountain\DOCMNT\REPORT\21676 - FTS Report - 64 Grandview Lane Bowen Mountain - Engnieering Development Report-Issue B.docx
2.3 RESERVE LAA
Photo 9 Rocky terrain and short distance to crest beyond which slope ismoderate to steep and unsuitable for LAA in sandy soils due to
ineffective treatment, extent of rock and risk of erosion (sandy top soils)
Access to the subject property has not been available but the typical scenario of the terrain is depicted in the above photo for the virgin landscape. The DA only permitted clearing of the undergrowth within the APZ areas which also house the DA approved LAA’s. In this case the area shown is the reserve area which is meant to be 1000 sqm. Obviously the rockiness would require a larger land area for the LAA to be effective in reducing contaminants. This reduces the capacity of the land to be sewered due to the smaller effective LAA available.
2.4 NEARBY FARM DAM
A farm dam is situated within 25 m of the site and with the proposed LAA designed for the front of the property places it within the 40 m limit set by council. The setbacks required by council (obtained from DA assessment team) are as follows:
“The following information shall be taken into account when considering the system. The minimum horizontal distance from the perimeter of the disposal area to the following areas shall be:
100 metres to permanent surface water (i.e. rivers, creeks, lakes, etc.);250 metres to domestic groundwater well;40 metres to other waters (i.e. farm dams, intermittent waterways and drainage channels, etc.);6 metres if area up-gradient and 3 metres if area down-gradient of driveways and property boundaries;15 metres to dwellings; 3 metres to paths and walkways and
INFRASTRUCTURE DEVELOPMENT PLANNING REPORT 56 GRANDVIEW LANE, BOWEN MOUNTAIN NSW 2753Issue B – 11th December 2016
21676 Page 14D:\DOCUMENTS\21676 - 56 Grandview Lane Bowen Mountain\DOCMNT\REPORT\21676 - FTS Report - 64 Grandview Lane Bowen Mountain - Engnieering Development Report-Issue B.docx
6 metres to swimming pools.”
2.5 SEWER OPERATION
The construction and operation of the On-site Sewerage system must only be as approved by the local Council and this is stipulated in section 68 and 68A of the Local Government act 1993. It is therefore recommended that Council review its compliance requirements because it has issued an interim occupation certificate without the approved LAA areas being operational and the lawn areas currently being used verified as being properly tested in accordance with the laws and statutes to perform without polluting. Given the likely LAA sizes assessed by FTS the required level of performance cannot be achieved and as such this warrants an independent investigation by a professional effluent, soil and environmental specialist.
3 CALCULATIONSThe Bioseptic Performa plant is certified to service up to 10 persons. For more than 10 persons, the Jumbo is necessary, or a duplication of the original plant.
A preliminary assessment by water balance model was undertaken and the results provide the following minimum required LAA areas for the given land use areas assuming good ground coverage (i.e. not rocky).
The calculations by FTS are only to assess the LAA areas for the likely usage of the site. The LAA are adjusted to suit the particular site conditions.
People Daily Demand Irrigation Rate LAA Reserve6 900 l/day 2.5 mm/day 570 sqm 570 sqm8 1200 l/d 2.5 mm/day 760 sqm 760 sqm10 1500 l/d 2.5 mm/day 950 sqm 950 sqm12 1800 l/d 2.5 mm/day 1140 sqm 1140 sqm
FTS prepared to drawings 21676-P01 and P02 to show the various changes that have occurred or are proposed to the site.
Items in black are the native features.Items in pink are as per the DA 116/11 for the Attached Dual Occupancy then down rated to a Single Dwelling with attached Studio which was approved given sewer constraints it is presumed. (Owners value of $181,500).Items in cyan are from the sewerage consultant and form part of S0014/11 Septic Tank Application associated with the Single Dwelling.Items in Green are the as built works pursuant to the CC and Council Inspections and for the change of use application to a Dual Occupancy DA 0685/15.Items in Red are for the Barn application DA 142/15. (Owners value of $26,000).
INFRASTRUCTURE DEVELOPMENT PLANNING REPORT 56 GRANDVIEW LANE, BOWEN MOUNTAIN NSW 2753Issue B – 11th December 2016
21676 Page 15D:\DOCUMENTS\21676 - 56 Grandview Lane Bowen Mountain\DOCMNT\REPORT\21676 - FTS Report - 64 Grandview Lane Bowen Mountain - Engnieering Development Report-Issue B.docx
Items in Purple are for a new development application for double story alterations and additions – DA480/16. (Owners value $288,000)
Based on the various works erected on site to date, only 610 sqm of the original 1000 sqm remains. Of that, almost all the front area is within 40 m of the dam on the nearby property down the hill. That leaves only 210 sqm of original primary LAA. The additional areas added by the owner total 175 sqm so far and these are adjacent to the house and irrigated by spray irrigation (client advice) rather than drip irrigators. The rocky terrain being about 50% of the surface makes the effective LAA possibly only 50% of the land area and the reserve area to the back of the house is probably even less effective due to the slope and soil conditions. By the Onsite Sewerage code, the LAA is insufficient for the development already built andthe barn needs to be relocated to the location of the proposed double storey addition and the original primary LAA made operational and extended to achieve a more suitable treatment system with appropriate setbacks from the dam and other constraints. This would provide a total LAA of 390 sqm per original DA plus the 175 sqm already operating, and perhaps an additional 195 sqm by expansion of the existing treatment lawn areas to achieve 760 sqm as required for the a maximum of 8 persons to live there. The status of operation of the current AWTS and LAA’s including soil testing is warranted with monitoring and reporting enforced. The current proposal before council should be refused on the basis of land constraints for the sewerage system and in our opinion the land is already at and possibly over its capacity to support the sites current level of development.
4 CONCLUSION
An full independent review of the development and the sewerage system is required due to the extensive variations that have occurred on the site to the LAA, site conditions and terrain, setback locations, capacity of the soil to provide suitable tertiary treatment, and performance of the AWTS including commissioning test and maintenance and performance to date. The progress of this project in terms of protocols and engineering practice as required by EPA guidelines and the LGA ad Regulations is unsatisfactory in our opinion particularly in respect of the risk to public health and the environment. Minimum requirements are set out in the AS1547 standard for On-site Domestic Wasterwater Management.
The current proposal before council should be refused on the basis of land constraints forthe sewerage system and in our opinion the land is already at and possibly over its capacity to support the site’s current level of development.
INFRASTRUCTURE DEVELOPMENT PLANNING REPORT 56 GRANDVIEW LANE, BOWEN MOUNTAIN NSW 2753Issue B – 11th December 2016
21676 Page 16D:\DOCUMENTS\21676 - 56 Grandview Lane Bowen Mountain\DOCMNT\REPORT\21676 - FTS Report - 64 Grandview Lane Bowen Mountain - Engnieering Development Report-Issue B.docx
APPENDICES DRAWINGSPRODUCT INFORMATIONWATER BALANCES FOR 900, 1200, 1500 AND 1800 L/DAYHAWKESBURY SOIL LANDSCAPE INFORMATION
Lan
d C
apab
ility
Asse
ssm
ent F
ram
ewor
k
Plea
se re
ad th
e at
tach
ed n
otes
bef
ore
usin
g th
is s
prea
dshe
et
Site
Add
ress
:D
ate:
11 D
ec 2
016
Dan
iel L
eeIN
PUT
DAT
AD
esig
n W
aste
wat
er F
low
Q90
0L/
day
Base
d on
max
imum
pot
entia
l occ
upan
cy a
nd d
eriv
ed fr
om T
able
4 in
the
EPA
Cod
e of
Pra
ctic
e (2
013)
Des
ign
Irrig
atio
n R
ate
DIR
2.5
mm
/day
Base
d on
soi
l tex
ture
cla
ss/p
erm
eabi
lity
and
deriv
ed fr
om T
able
9 in
the
EPA
Cod
e of
Pra
ctic
e (2
013)
Nom
inat
ed L
and
Appl
icat
ion
Area
L57
0m
21
Cro
p Fa
ctor
C0.
6-0.
8un
itles
sEs
timat
es e
vapo
trans
pira
tion
as a
frac
tion
of p
an e
vapo
ratio
n; v
arie
s w
ith s
easo
n an
d cr
op ty
pe2
Rai
nfal
l Run
off F
acto
rR
F1.
0un
tiles
sPr
opor
tion
of ra
infa
ll th
at re
mai
ns o
nsite
and
infil
trate
s, a
llow
ing
for a
ny ru
noff
Mea
n M
onth
ly R
ainf
all D
ata
BoM
Sta
tion
and
num
ber
Mea
n M
onth
ly P
an E
vapo
ratio
n D
ata
BoM
Sta
tion
and
num
ber
Para
met
erSy
mbo
lFo
rmul
aU
nits
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Tota
lD
ays
in m
onth
Dda
ys31
2831
3031
3031
3130
3130
3136
5R
ainf
all
Rm
m/m
onth
87.2
116.
970
.760
.647
.554
.329
.633
.946
.147
.479
.569
.274
2.9
Eva p
orat
ion
Em
m/m
onth
180
135
128
8558
4543
5888
127
152
163
1262
Cro
p Fa
ctor
Cun
itles
s0.
800.
800.
700.
700.
600.
600.
600.
600.
700.
800.
800.
80O
UTP
UTS Ev
apot
rans
pira
tion
ETEx
Cm
m/m
onth
144
108
9060
3527
2635
6210
212
213
093
8.7
Perc
olat
ion
BD
IRxD
mm
/mon
th77
.570
77.5
75.0
77.5
75.0
77.5
77.5
75.0
77.5
75.0
77.5
912.
5O
utpu
tsET
+Bm
m/m
onth
221.
517
816
7.1
134.
511
2.3
102.
010
3.3
112.
313
6.6
179.
119
6.6
207.
918
51.2
INPU
TSR
etai
ned
Rai
nfal
lR
RR
xRF
mm
/mon
th87
.211
6.9
70.7
60.6
47.5
54.3
29.6
33.9
46.1
47.4
79.5
69.2
742.
9Ap
plie
d Ef
fluen
tW
(QxD
)/Lm
m/m
onth
48.9
44.2
48.9
47.4
48.9
47.4
48.9
48.9
47.4
48.9
47.4
48.9
576.
3In
puts
RR
+Wm
m/m
onth
136.
116
1.1
119.
610
8.0
96.4
101.
778
.582
.893
.596
.312
6.9
118.
113
19.2
STO
RAG
E C
ALC
ULA
TIO
NSt
orag
e re
mai
ning
from
pre
viou
s m
onth
mm
/mon
th0.
00.
00.
00.
00.
00.
00.
00.
00.
00.
00.
00.
0St
ora g
e fo
r the
mon
thS
(RR
+W)-(
ET+B
)m
m/m
onth
-85.
4-1
6.9
-47.
5-2
6.5
-15.
9-0
.3-2
4.8
-29.
5-4
3.1
-82.
8-6
9.7
-89.
8C
umul
ativ
e St
ora g
eM
mm
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Max
imum
Sto
rage
for N
omin
ated
Are
aN
mm
0.00
VN
xLL
0LA
ND
AR
EA R
EQU
IRED
FO
R Z
ERO
STO
RAG
Em
220
841
228
936
543
156
637
935
629
821
223
120
1
567.
0m
2
CEL
LSPl
ease
ent
er d
ata
in b
lue
cells
XXR
ed c
ells
are
aut
omat
ical
ly p
opul
ated
by
the
spre
adsh
eet
XXD
ata
in y
ello
w c
ells
is c
alcu
late
d by
the
spre
adsh
eet,
DO
NO
T AL
TER
TH
ESE
CEL
LS
NO
TES
1 Thi
s va
lue
shou
ld b
e th
e la
rges
t of t
he fo
llow
ing:
land
app
licat
ion
area
requ
ired
base
d on
the
mos
t lim
iting
nut
rient
bal
ance
or m
inim
um a
rea
requ
ired
for z
ero
stor
age
2 Val
ues
sele
cted
are
sui
tabl
e fo
r pas
ture
gra
ss in
Vic
toria
Irrig
atio
n ar
ea s
izin
g us
ing
Nom
inat
ed A
rea
Wat
er B
alan
ce fo
r Zer
o St
orag
e
MIN
IMU
M A
REA
REQ
UIR
ED F
OR
ZER
O S
TOR
AGE:
Ric
hmon
d R
AAF
Sydn
ey V
alue
s
64 G
rand
view
Lan
e B
owen
Mou
ntai
nAs
sess
or:
Lan
d C
apab
ility
Asse
ssm
ent F
ram
ewor
k
Plea
se re
ad th
e at
tach
ed n
otes
bef
ore
usin
g th
is s
prea
dshe
et
Site
Add
ress
:D
ate:
11 D
ec 2
016
Dan
iel L
eeIN
PUT
DAT
AD
esig
n W
aste
wat
er F
low
Q1,
200
L/da
yBa
sed
on m
axim
um p
oten
tial o
ccup
ancy
and
der
ived
from
Tab
le 4
in th
e EP
A C
ode
of P
ract
ice
(201
3)D
esig
n Irr
igat
ion
Rat
eD
IR2.
5m
m/d
ayBa
sed
on s
oil t
extu
re c
lass
/per
mea
bilit
y an
d de
rived
from
Tab
le 9
in th
e EP
A C
ode
of P
ract
ice
(201
3)N
omin
ated
Lan
d Ap
plic
atio
n Ar
eaL
760
m2
1
Cro
p Fa
ctor
C0.
6-0.
8un
itles
sEs
timat
es e
vapo
trans
pira
tion
as a
frac
tion
of p
an e
vapo
ratio
n; v
arie
s w
ith s
easo
n an
d cr
op ty
pe2
Rai
nfal
l Run
off F
acto
rR
F1.
0un
tiles
sPr
opor
tion
of ra
infa
ll th
at re
mai
ns o
nsite
and
infil
trate
s, a
llow
ing
for a
ny ru
noff
Mea
n M
onth
ly R
ainf
all D
ata
BoM
Sta
tion
and
num
ber
Mea
n M
onth
ly P
an E
vapo
ratio
n D
ata
BoM
Sta
tion
and
num
ber
Para
met
erSy
mbo
lFo
rmul
aU
nits
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Tota
lD
ays
in m
onth
Dda
ys31
2831
3031
3031
3130
3130
3136
5R
ainf
all
Rm
m/m
onth
87.2
116.
970
.760
.647
.554
.329
.633
.946
.147
.479
.569
.274
2.9
Eva p
orat
ion
Em
m/m
onth
180
135
128
8558
4543
5888
127
152
163
1262
Cro
p Fa
ctor
Cun
itles
s0.
800.
800.
700.
700.
600.
600.
600.
600.
700.
800.
800.
80O
UTP
UTS Ev
apot
rans
pira
tion
ETEx
Cm
m/m
onth
144
108
9060
3527
2635
6210
212
213
093
8.7
Perc
olat
ion
BD
IRxD
mm
/mon
th77
.570
77.5
75.0
77.5
75.0
77.5
77.5
75.0
77.5
75.0
77.5
912.
5O
utpu
tsET
+Bm
m/m
onth
221.
517
816
7.1
134.
511
2.3
102.
010
3.3
112.
313
6.6
179.
119
6.6
207.
918
51.2
INPU
TSR
etai
ned
Rai
nfal
lR
RR
xRF
mm
/mon
th87
.211
6.9
70.7
60.6
47.5
54.3
29.6
33.9
46.1
47.4
79.5
69.2
742.
9Ap
plie
d Ef
fluen
tW
(QxD
)/Lm
m/m
onth
48.9
44.2
48.9
47.4
48.9
47.4
48.9
48.9
47.4
48.9
47.4
48.9
576.
3In
puts
RR
+Wm
m/m
onth
136.
116
1.1
119.
610
8.0
96.4
101.
778
.582
.893
.596
.312
6.9
118.
113
19.2
STO
RAG
E C
ALC
ULA
TIO
NSt
orag
e re
mai
ning
from
pre
viou
s m
onth
mm
/mon
th0.
00.
00.
00.
00.
00.
00.
00.
00.
00.
00.
00.
0St
ora g
e fo
r the
mon
thS
(RR
+W)-(
ET+B
)m
m/m
onth
-85.
4-1
6.9
-47.
5-2
6.5
-15.
9-0
.3-2
4.8
-29.
5-4
3.1
-82.
8-6
9.7
-89.
8C
umul
ativ
e St
ora g
eM
mm
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Max
imum
Sto
rage
for N
omin
ated
Are
aN
mm
0.00
VN
xLL
0LA
ND
AR
EA R
EQU
IRED
FO
R Z
ERO
STO
RAG
Em
227
755
038
648
757
475
550
547
439
828
230
726
8
755.
0m
2
CEL
LSPl
ease
ent
er d
ata
in b
lue
cells
XXR
ed c
ells
are
aut
omat
ical
ly p
opul
ated
by
the
spre
adsh
eet
XXD
ata
in y
ello
w c
ells
is c
alcu
late
d by
the
spre
adsh
eet,
DO
NO
T AL
TER
TH
ESE
CEL
LS
NO
TES
1 Thi
s va
lue
shou
ld b
e th
e la
rges
t of t
he fo
llow
ing:
land
app
licat
ion
area
requ
ired
base
d on
the
mos
t lim
iting
nut
rient
bal
ance
or m
inim
um a
rea
requ
ired
for z
ero
stor
age
2 Val
ues
sele
cted
are
sui
tabl
e fo
r pas
ture
gra
ss in
Vic
toria
Irrig
atio
n ar
ea s
izin
g us
ing
Nom
inat
ed A
rea
Wat
er B
alan
ce fo
r Zer
o St
orag
e
MIN
IMU
M A
REA
REQ
UIR
ED F
OR
ZER
O S
TOR
AGE:
Ric
hmon
d R
AAF
Sydn
ey V
alue
s
64 G
rand
view
Lan
e B
owen
Mou
ntai
nAs
sess
or:
Lan
d C
apab
ility
Asse
ssm
ent F
ram
ewor
k
Plea
se re
ad th
e at
tach
ed n
otes
bef
ore
usin
g th
is s
prea
dshe
et
Site
Add
ress
:D
ate:
11 D
ec 2
016
Dan
iel L
eeIN
PUT
DAT
AD
esig
n W
aste
wat
er F
low
Q1,
500
L/da
yBa
sed
on m
axim
um p
oten
tial o
ccup
ancy
and
der
ived
from
Tab
le 4
in th
e EP
A C
ode
of P
ract
ice
(201
3)D
esig
n Irr
igat
ion
Rat
eD
IR2.
5m
m/d
ayBa
sed
on s
oil t
extu
re c
lass
/per
mea
bilit
y an
d de
rived
from
Tab
le 9
in th
e EP
A C
ode
of P
ract
ice
(201
3)N
omin
ated
Lan
d Ap
plic
atio
n Ar
eaL
950
m2
1
Cro
p Fa
ctor
C0.
6-0.
8un
itles
sEs
timat
es e
vapo
trans
pira
tion
as a
frac
tion
of p
an e
vapo
ratio
n; v
arie
s w
ith s
easo
n an
d cr
op ty
pe2
Rai
nfal
l Run
off F
acto
rR
F1.
0un
tiles
sPr
opor
tion
of ra
infa
ll th
at re
mai
ns o
nsite
and
infil
trate
s, a
llow
ing
for a
ny ru
noff
Mea
n M
onth
ly R
ainf
all D
ata
BoM
Sta
tion
and
num
ber
Mea
n M
onth
ly P
an E
vapo
ratio
n D
ata
BoM
Sta
tion
and
num
ber
Para
met
erSy
mbo
lFo
rmul
aU
nits
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Tota
lD
ays
in m
onth
Dda
ys31
2831
3031
3031
3130
3130
3136
5R
ainf
all
Rm
m/m
onth
87.2
116.
970
.760
.647
.554
.329
.633
.946
.147
.479
.569
.274
2.9
Eva p
orat
ion
Em
m/m
onth
180
135
128
8558
4543
5888
127
152
163
1262
Cro
p Fa
ctor
Cun
itles
s0.
800.
800.
700.
700.
600.
600.
600.
600.
700.
800.
800.
80O
UTP
UTS Ev
apot
rans
pira
tion
ETEx
Cm
m/m
onth
144
108
9060
3527
2635
6210
212
213
093
8.7
Perc
olat
ion
BD
IRxD
mm
/mon
th77
.570
77.5
75.0
77.5
75.0
77.5
77.5
75.0
77.5
75.0
77.5
912.
5O
utpu
tsET
+Bm
m/m
onth
221.
517
816
7.1
134.
511
2.3
102.
010
3.3
112.
313
6.6
179.
119
6.6
207.
918
51.2
INPU
TSR
etai
ned
Rai
nfal
lR
RR
xRF
mm
/mon
th87
.211
6.9
70.7
60.6
47.5
54.3
29.6
33.9
46.1
47.4
79.5
69.2
742.
9Ap
plie
d Ef
fluen
tW
(QxD
)/Lm
m/m
onth
48.9
44.2
48.9
47.4
48.9
47.4
48.9
48.9
47.4
48.9
47.4
48.9
576.
3In
puts
RR
+Wm
m/m
onth
136.
116
1.1
119.
610
8.0
96.4
101.
778
.582
.893
.596
.312
6.9
118.
113
19.2
STO
RAG
E C
ALC
ULA
TIO
NSt
orag
e re
mai
ning
from
pre
viou
s m
onth
mm
/mon
th0.
00.
00.
00.
00.
00.
00.
00.
00.
00.
00.
00.
0St
ora g
e fo
r the
mon
thS
(RR
+W)-(
ET+B
)m
m/m
onth
-85.
4-1
6.9
-47.
5-2
6.5
-15.
9-0
.3-2
4.8
-29.
5-4
3.1
-82.
8-6
9.7
-89.
8C
umul
ativ
e St
ora g
eM
mm
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Max
imum
Sto
rage
for N
omin
ated
Are
aN
mm
0.00
VN
xLL
0LA
ND
AR
EA R
EQU
IRED
FO
R Z
ERO
STO
RAG
Em
234
668
748
260
971
894
363
159
349
735
338
433
5
944.
0m
2
CEL
LSPl
ease
ent
er d
ata
in b
lue
cells
XXR
ed c
ells
are
aut
omat
ical
ly p
opul
ated
by
the
spre
adsh
eet
XXD
ata
in y
ello
w c
ells
is c
alcu
late
d by
the
spre
adsh
eet,
DO
NO
T AL
TER
TH
ESE
CEL
LS
NO
TES
1 Thi
s va
lue
shou
ld b
e th
e la
rges
t of t
he fo
llow
ing:
land
app
licat
ion
area
requ
ired
base
d on
the
mos
t lim
iting
nut
rient
bal
ance
or m
inim
um a
rea
requ
ired
for z
ero
stor
age
2 Val
ues
sele
cted
are
sui
tabl
e fo
r pas
ture
gra
ss in
Vic
toria
Irrig
atio
n ar
ea s
izin
g us
ing
Nom
inat
ed A
rea
Wat
er B
alan
ce fo
r Zer
o St
orag
e
MIN
IMU
M A
REA
REQ
UIR
ED F
OR
ZER
O S
TOR
AGE:
Ric
hmon
d R
AAF
Sydn
ey V
alue
s
64 G
rand
view
Lan
e B
owen
Mou
ntai
nAs
sess
or:
Lan
d C
apab
ility
Asse
ssm
ent F
ram
ewor
k
Plea
se re
ad th
e at
tach
ed n
otes
bef
ore
usin
g th
is s
prea
dshe
et
Site
Add
ress
:D
ate:
11 D
ec 2
016
Dan
iel L
eeIN
PUT
DAT
AD
esig
n W
aste
wat
er F
low
Q1,
800
L/da
yBa
sed
on m
axim
um p
oten
tial o
ccup
ancy
and
der
ived
from
Tab
le 4
in th
e EP
A C
ode
of P
ract
ice
(201
3)D
esig
n Irr
igat
ion
Rat
eD
IR2.
5m
m/d
ayBa
sed
on s
oil t
extu
re c
lass
/per
mea
bilit
y an
d de
rived
from
Tab
le 9
in th
e EP
A C
ode
of P
ract
ice
(201
3)N
omin
ated
Lan
d Ap
plic
atio
n Ar
eaL
1140
m2
1
Cro
p Fa
ctor
C0.
6-0.
8un
itles
sEs
timat
es e
vapo
trans
pira
tion
as a
frac
tion
of p
an e
vapo
ratio
n; v
arie
s w
ith s
easo
n an
d cr
op ty
pe2
Rai
nfal
l Run
off F
acto
rR
F1.
0un
tiles
sPr
opor
tion
of ra
infa
ll th
at re
mai
ns o
nsite
and
infil
trate
s, a
llow
ing
for a
ny ru
noff
Mea
n M
onth
ly R
ainf
all D
ata
BoM
Sta
tion
and
num
ber
Mea
n M
onth
ly P
an E
vapo
ratio
n D
ata
BoM
Sta
tion
and
num
ber
Para
met
erSy
mbo
lFo
rmul
aU
nits
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Tota
lD
ays
in m
onth
Dda
ys31
2831
3031
3031
3130
3130
3136
5R
ainf
all
Rm
m/m
onth
87.2
116.
970
.760
.647
.554
.329
.633
.946
.147
.479
.569
.274
2.9
Eva p
orat
ion
Em
m/m
onth
180
135
128
8558
4543
5888
127
152
163
1262
Cro
p Fa
ctor
Cun
itles
s0.
800.
800.
700.
700.
600.
600.
600.
600.
700.
800.
800.
80O
UTP
UTS Ev
apot
rans
pira
tion
ETEx
Cm
m/m
onth
144
108
9060
3527
2635
6210
212
213
093
8.7
Perc
olat
ion
BD
IRxD
mm
/mon
th77
.570
77.5
75.0
77.5
75.0
77.5
77.5
75.0
77.5
75.0
77.5
912.
5O
utpu
tsET
+Bm
m/m
onth
221.
517
816
7.1
134.
511
2.3
102.
010
3.3
112.
313
6.6
179.
119
6.6
207.
918
51.2
INPU
TSR
etai
ned
Rai
nfal
lR
RR
xRF
mm
/mon
th87
.211
6.9
70.7
60.6
47.5
54.3
29.6
33.9
46.1
47.4
79.5
69.2
742.
9Ap
plie
d Ef
fluen
tW
(QxD
)/Lm
m/m
onth
48.9
44.2
48.9
47.4
48.9
47.4
48.9
48.9
47.4
48.9
47.4
48.9
576.
3In
puts
RR
+Wm
m/m
onth
136.
116
1.1
119.
610
8.0
96.4
101.
778
.582
.893
.596
.312
6.9
118.
113
19.2
STO
RAG
E C
ALC
ULA
TIO
NSt
orag
e re
mai
ning
from
pre
viou
s m
onth
mm
/mon
th0.
00.
00.
00.
00.
00.
00.
00.
00.
00.
00.
00.
0St
ora g
e fo
r the
mon
thS
(RR
+W)-(
ET+B
)m
m/m
onth
-85.
4-1
6.9
-47.
5-2
6.5
-15.
9-0
.3-2
4.8
-29.
5-4
3.1
-82.
8-6
9.7
-89.
8C
umul
ativ
e St
ora g
eM
mm
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Max
imum
Sto
rage
for N
omin
ated
Are
aN
mm
0.00
VN
xLL
0LA
ND
AR
EA R
EQU
IRED
FO
R Z
ERO
STO
RAG
Em
241
582
557
973
186
111
3275
771
259
742
446
140
2
1133
.0m
2
CEL
LSPl
ease
ent
er d
ata
in b
lue
cells
XXR
ed c
ells
are
aut
omat
ical
ly p
opul
ated
by
the
spre
adsh
eet
XXD
ata
in y
ello
w c
ells
is c
alcu
late
d by
the
spre
adsh
eet,
DO
NO
T AL
TER
TH
ESE
CEL
LS
NO
TES
1 Thi
s va
lue
shou
ld b
e th
e la
rges
t of t
he fo
llow
ing:
land
app
licat
ion
area
requ
ired
base
d on
the
mos
t lim
iting
nut
rient
bal
ance
or m
inim
um a
rea
requ
ired
for z
ero
stor
age
2 Val
ues
sele
cted
are
sui
tabl
e fo
r pas
ture
gra
ss in
Vic
toria
Irrig
atio
n ar
ea s
izin
g us
ing
Nom
inat
ed A
rea
Wat
er B
alan
ce fo
r Zer
o St
orag
e
MIN
IMU
M A
REA
REQ
UIR
ED F
OR
ZER
O S
TOR
AGE:
Ric
hmon
d R
AAF
Sydn
ey V
alue
s
64 G
rand
view
Lan
e B
owen
Mou
ntai
nAs
sess
or:
63
ha HAWKESBURY Colluvial
Landscape—rugged, rolling to very steep hills on Hawkesbury Sandstone. Local relief 40–200 m, slopes >25%. Rock outcrop >50%. Narrow crests and ridges, narrow incised valleys, steep sideslopes with rocky benches, broken scarps and boulders. Mostly uncleared Eucalypt open-woodland (dry sclerophyll forest) and tall open-forest (wet sclerophyll forest).
Soils—shallow (<50 cm), discontinuous lithosols/siliceous sands (Uc1.21) associated with rock outcrop; earthy sands (Uc5.11, Uc5.23), yellow earths (Gn2.24) and some locally deep sands on inside of benches and along joints and fractures; localised yellow and red podzolic soils (Dy4.11, Dy5.21, Dr5.11, Dr5.21) associated with shale lenses; siliceous sands (Uc1.2) and secondary yellow earths (Gn2.41) along drainage lines.
Limitations—steep slopes, mass movement hazard, rockfall hazard, water erosion hazard, shallow soils, rock outcrop, non-cohesive soils (localised), stony, highly permeable soils of low fertility.
LOCATION
Steep, rugged Hawkesbury Sandstone slopes and ridges of the Hornsby Plateau in the north east, the Blue Mountains Plateau in the west and Woronora Plateau in the south east.
LANDSCAPE
Geology
Hawkesbury Sandstone consisting of medium to coarse-grained quartz sandstone with minor shale and laminite lenses. Sandstones are either massive or crossbedded sheet facies with vertical or subvertical joint sets. The combination of bedding planes and widely spaced joints gives sandstone outcrops a distinctive blocky appearance.
64
Topography
Rolling to very steep hills. Local relief varies from 40–200 m. Slope gradients range from 25–70%. Crests and ridges are convex and narrow, and <300 m wide Slopes are moderately inclined to precipitous. Rock outcrop occurs as horizontal benches and broken scarps up to 10 m high. Boulders and cobbles cover up to 50% of the ground surface. Valleys are narrow and incised.
Vegetation
Mostly uncleared open-woodland (dry sclerophyll) with pockets of tall open-forest (wet sclerophyll) and closed-forest (rainforest).
On exposed crests and ridges there is usually a low open woodland containing Eucalyptus gummifera (red bloodwood), E. oblonga (narrow-leaved stringybark), E. haemastoma (scribbly gum) and E. sclerophylla(hard-leaved scribbly gum), E. capitellata (brown stringybark) and Banksia serrata (old man banksia). Onthe more sheltered sideslopes a dry sclerophyll open-forest containing E.sieberi (black ash), E. piperita(Sydney peppermint), Angophora costata (smooth-barked apple) and Allocasuarina littoralis (black she-oak) predominates.The understorey is dominated by shrub species of the families Epacridaceae, Myrtaceae, Fabaceae and Proteaceae.
Within sheltered gullies, wet sclerophyll closed-forests of Eucalyptus pilularis (blackbutt), E. saligna(Sydney blue gum), Tristaniopsis laurina (water gum) and occasionally Ceratopetalum apetalum(coachwood) occur. Callicoma serratifolia (black wattle), Backhousia myrtifolia (native myrtle) and Pteridium esculentum (bracken) form a closed scrubby understorey.
Landuse
Mostly National Park (Blue Mountains National Park at Glenbrook) which is used for nature conservation, education and recreation, and Water Board catchment.
Existing Erosion
Severe sheet erosion often occurs during storms and after ground cover is destroyed by bushfires (Atkinson, 1984). Minor gully erosion occurs along unpaved tracks and fire trails, especially those used regularly by four wheel drive vehicles, motorcycles and horses.
Associated Soil Landscapes
Small areas of Faulconbridge (fb), Lucas Heights (lh), Gymea (gy) and Volcanic (vo) soil landscapes occur in association with the Hawkesbury soil landscape.
SOILS
Dominant Soil Materials
ha1—Loose, coarse quartz sand.
This is a sand to sandy loam with loose, apedal single-grained structure and porous sandy fabric. It generally occurs as topsoil (A1 horizon).
Colour ranges from brownish black (10YR 3/2) when abundant organic matter is present, to bright yellowish brown (10YR 7/6) and often becomes lighter with depth. The pH ranges from strongly acid (pH 4.0) to moderately acid (pH 5.5). Weakly weathered sandstone fragments may be present whilst charcoal fragments and roots are common. This material is commonly water repellent.
ha2—Earthy, yellowish brown sandy clay loam
This is a clayey sand to sandy clay loam with apedal massive or occasionally weakly pedal structure and a distinctly porous, earthy fabric. It generally occurs as subsoil, often in association with sandstone bedrock (B or C horizon).
Where peds are present they are large sub-angular blocky and rough-faced. Ped sizes range from 30–60 mm. Common colours include yellow orange (10YR 7/8), bright yellowish brown (10YR 6/8, 6/6) and yellowish brown (10YR 5/6) The pH ranges from strongly acid (pH 4.0) to moderately acid (pH 5.5). Gravels, stones and ironstone-plated sandstone fragments are common but roots and charcoal fragments are rare.
65
ha3—Pale, strongly pedal light clay.
This is fine sandy clay loam to medium clay with strongly pedal structure and rough-faced ped fabric. It commonly occurs as subsoil derived from shale lenses within the Hawkesbury Sandstone (B or C horizons) but does not always occur.
Structure is strongly pedal when dry and apedal when saturated. Peds range in size from 20–60 mm and are subangular blocky to angular blocky in shape. Colours are most often pale but can vary according to site drainage characteristics. Colour ranges from bright yellowish brown (10YR 6/6) to reddish brown (5YR 5/6). Red, orange and grey mottles are often present. The pH varies from strongly acid (pH 4.0) to moderately acid (pH 5.5). Stratified iron-stone gravels are common but roots and charcoal fragments are usually rare or absent.
Associated Soil Materials
Litter and decomposing organic debris. Surface litter consists of decomposing remnants of leaves and twigs, fungal and root mats, and quartz sand grains. Distribution depends on site productivity, fire regime, location of nearby species and surface wetness. More than 10 cm of decomposing organic debris often accumulates indebris dams and small fans on breaks of slope, as well as in joint crevices of rock outcrops. There is usually a sharp boundary with the mineral soil.
White loose sand.
This material is found on the surface and is composed of quartz sand grains found in recently deposited surface washes such as small debris dams and fans found on breaks of slope. This material is often mixed with litter and charcoal fragments.
Occurrence and Relationships
Crests and ridges. Up to 20 cm of loose, coarse quartz sand (ha1) overlies either bedrock [lithosols Uc1.21) or <30 cm of earthy, yellowish brown sandy clay loam subsoil (ha2) [earthy sands Uc5.11), yellow earths (Gn2.24, Gn2.31)]. Total soil depth is <50 cm. The boundary between soil materials is usually gradational. Texture often increases gradually with depth.
Sideslopes and benches. Soils are discontinuous. Sandstone outcrop and boulders may cover >50% of the ground surface. Usually 10–30 cm of ha1 overlies bedrock [lithosols and siliceous sands (Uc1.22)] on outsides of benches whilst on higher sides of benches 5–15 cm of ha1 overlies up to 50 cm of ha2 [yellow earths (Gn2.24)] or locally deep sands. Boundaries between soil materials are either gradual or clear and total soil depth, although variable, is usually <70 cm. In some instances, especially along joint lines, soil depth may exceed 200 cm. Often ha2 is found along bedding planes in the sandstone.
Minor lenses of shale are occasionally associated with higher sides of benches and have up to 30 cm of ha1which overlies up to 50 cm of strongly pedal clay subsoil (ha3). There is a clear to sharp boundary between soil materials [yellow podzolic soils Dy4.11, Dy5.21) with occasional red podzolic soils (Dr5.11, Dr52.1)]. Total soil depth is usually <150 cm.
Drainage lines. Drainage lines are either on exposed bedrock or have deposits of gravel or loose quartz sand (ha1) [siliceous sands (Uc1.2)] which occasionally overlie ha2 [yellow earths (Gn2.41)]. Total soil depth is usually <100 cm.
LIMITATIONS TO DEVELOPMENT
Soil Limitations
ha1 High permeability Low available water capacity Low fertility High erodibility Strongly acid
ha2 Stoniness (localised) High permeability (localised) Very low fertility High erodibility
66
ha3 Very low fertility Strongly acid High erodibility FertilityGeneral fertility is very low. The soils of this unit are moderately to strongly acid with a low to very low nutrient status. The soils are severely deficient in nitrogen and phosphorus and they have very low CEC. They are also shallow and stony with low available water capacities and high aluminium toxicity.
ErodibilityThe topsoil ha1 has low erodibility. It consists of highly permeable, loose, coarse sands and organic matter. ha1 is highly susceptible to concentrated flow erosion, especially when the organic matter is removed by hot bushfires. ha2 and ha3 have moderate erodibility. They have low organic matter contents and weak fabrics.
Erosion Hazard Erosion hazard for non-concentrated flows is generally very high and ranges from moderate to extreme.
Surface Movement Potential The shallow sandy soils are stable to slightly reactive.
Landscape Limitations Steep slopes, mass movement hazard, rockfall hazard, water erosion hazard, shallow soils, rock outcrop, non-cohesive soils (localised).
Urban Capability Generally not capable of urban development.
Rural Capability Not capable of being cultivated or grazed.
Distribution diagram of the Hawkesbury soil landscape showing the occurrence and relationship of dominant soil materials.