appendix e: soakaway tests -...

Martock Farms Limited Proposed Residential Development, Foldhill Lane FRA

Issue 1 June 2016

19 RMA Environmental RMA-C1579

Appendix E: Soakaway Tests

Soakaway Test Report

Land to the Southeast of Foldhill Lane, Martock, Somerset

Martock Farms Ltd April 2016 CG/JF/SR/16220/STR

Foldhill Lane, Martock Ruddlesden geotechnical

Soakaway Test Report Report Ref: CG/JF/SR/16220/STR

ii

REPORT CONTROL SHEET

Site address

Land to the Southeast of Foldhill Lane

Martock

Somerset

Client Martock Farms Ltd

Report title Soakaway Test Report

Issue date 14 April 2016

Report No. CG/JF/SR/16220/STR

Revision No. 0

Prepared by Catherine Greed

Signature

Position Engineering Geologist

Qualifications MSci (Hons). FGS.

Checked by James Field

Signature

Position Senior Engineering Geologist

Qualifications BSc (Hons). FGS.

Approved by Simon Ruddlesden

Signature

Position Director

Qualifications BSc (Hons). MSc. DIC. CGeol. FGS. EurGeol.

The Stables, 65 Langaton Lane,

Pinhoe, Exeter, EX1 3SP

01392 678082 [email protected] www.ruddlesden.co.uk

Catherine Greed

James Field

Simon Ruddlesden



iii

CONTENTS

1 INTRODUCTION 1 1.1 General 1 1.2 Development Proposals 1 1.3 Scope of Investigation 1 1.4 Scope of Report 1

THE SITE 2 2.1 Site Location 2 2.2 Site Description 2 2.3 Site Geology 2

FIELDWORK 4

RESULTS OF THE INVESTIGATION 5 4.1 General 5 4.2 Ground Conditions Encountered 5 4.3 Groundwater 5 4.4 Soakaway Test Results 6

DISCUSSION OF RESULTS AND RECOMMENDATIONS 7

REFERENCES 8

TERMS AND CONDITIONS 9 APPENDICES

APPENDIX A TRIAL PIT LOGS (4 pages)

APPENDIX B PHOTOGRAPHS (3 pages)

APPENDIX C SOAKAWAY TEST RESULTS (12 pages)

APPENDIX D PROPOSED SITE LAYOUT (1 page)

APPENDIX E SOAKAWAY TEST LOCATION PLAN (1 page)



1

1 INTRODUCTION

1.1 General

In April 2016, a soakaway test investigation was undertaken by Ruddlesden geotechnical ltd on behalf of Martock Farms Ltd at land to the southeast of Foldhill Lane, Martock, Somerset.

The investigation was undertaken to determine the permeability of the ground and to assess the suitability of the ground for soakaway drainage. The investigation comprised the formation of four soakaway tests in accordance with BRE Digest 365.

1.2 Development Proposals

It is understood that the site is to be developed for residential purposes with the construction of several houses with associated infrastructure. The proposed layout is enclosed within Appendix D of this report.

1.3 Scope of Investigation

The investigation covers aspects relating to soakaway drainage design. The brief was understood to comprise the following:

• Undertake in-situ soakaway testing in accordance with BRE 365. • Use data to provide soil infiltration rates. • Provide any other relevant comments relating to soakaway drainage design.

1.4 Scope of Report

The report is presented as a description of the procedures employed and the data obtained. This is followed by a description of the ground conditions and soakaway test results. The final part of the report comprises a discussion of results together with recommendations for soakaway design.



2

THE SITE

2.1 Site Location

The site is located on land to the southeast of Foldhill Lane, Martock, Somerset. The British National Grid Reference of the site is 346771, 119534 and the postcode is TA12 6PQ.

The site is located within a predominantly rural area, on the eastern outskirts of Martock village. The surrounding topography is hilly.

Access to the site is gained via a gateway in the west of the site, off Foldhill Lane.

2.2 Site Description

The site is roughly triangular in shape, measuring approximately 200m x 145m, and slopes gently down to the southwest, falling from a level of approximately 40mAOD in the northeastern corner of the site to a level of approximately 33mAOD in the southwest of the site.

The site comprises an agricultural field. A public footpath is present adjacent to the eastern boundary.

Overhead electricity cables cross the centre-west of the site, in a north-southwest orientation.

A ditch, with slow southwesterly flowing water, is present within the northwestern boundary. Several ponds of standing water were noted to the south of the site, in an overgrown area.

Mature mixed deciduous and coniferous trees, up to approximately 16m high, are present within the hedgerows bordering the site.

The site is bordered to the north-northwest by Foldhill Lane, before ‘La Fontana Care Home’ and fields, to the east by Foldhill Farm and fields and to the south by the dismantled railway and a public footpath before residential properties.

Photographs of the site are presented in Appendix B and a topographic survey showing the existing site layout is shown on the soakaway test location plan (Dwg No. 16220/02), presented in Appendix E of this report.

2.3 Site Geology

The British Geological Survey (BGS) map of the area indicates the site to be underlain by bedrock geology of the Jurassic Dyrham Formation, which is described as ‘pale to dark grey and greenish grey, silty and sandy mudstone, with interbeds of silt or very fine-grained sand (locally muddy or silty), weathering yellow’.

In addition, whilst not specifically mapped, superficial Quaternary Head deposits might be present overlying the (weathered) bedrock. Head deposits are formed by the reworking of earlier weathering products by periglacial processes. Head deposits generally consist of a heterogeneous mixture of local rock types in a matrix of fine sand, silt and/ or clay.

Several published historical BGS borehole records carried out approximately 1.2km to the southeast of the site, adjacent to the A303, which is considered to be the most characteristic of the ground conditions likely to be present at this site, encountered the following ground conditions:



3

• TOPSOIL, to a depths of between 0.20m and 0.30m, underlain by… • Firm and stiff brown CLAY with occasional small stones, to depths of between

0.60m and 1.10m, underlain by… • Stiff brown clay with pockets or lenses of blue CLAY and occasional stones

(Middle Lias), to depths of between 1.80m and 1.90m, underlain by… • Stiff grey shaley CLAY with some brown coloration on fissure planes (Middle

Lias), to depths of between 2.80m and 3.70m, underlain by… • Hard grey shaley CLAY, to the base of the borehole (Middle Lias), to depths

of between 3.00m and 5.00m. • Groundwater was encountered at depths of between approximately 0.90m

and 4.40mBGL (19.82mAOD and 23.70mAOD).



4

FIELDWORK

All fieldwork was undertaken on 05 April 2016.

Four soakaway tests were undertaken in accordance with BRE 365 “Soakaway Design”. The siting and setting out of the soakaway tests was determined by Ruddlesden geotechnical ltd.

The trial pit was excavated to a depth deemed sufficient to represent a section of the design soakaway. The vertical sides were trimmed square. A 1500-gallon water bowser was used to supply the large volumes of water required at a quick rate.

The pit was filled with water and allowed to drain. The fall in water level was recorded with time.

Trial pit logs and photographs, showing the ground conditions encountered, are presented in Appendix A and Appendix B; the soakaway testing results are presented in Appendix C; and a plan showing the soakaway test locations is presented in Appendix E of this report.



5

RESULTS OF THE INVESTIGATION

4.1 General

The following sections provide a summary of ground conditions encountered and soakaway testing results. Further details are provided in the appendices of this report.

4.2 Ground Conditions Encountered

4.2.1 Topsoil

Topsoil, comprising brown slightly gravelly silty clay with rare rootlets, was typically encountered to depths of between 0.30m and 0.40m below existing ground levels.

4.2.2 Natural Geology

Head Deposits

Beneath the topsoil, firm to stiff orangish brown and bluish grey (slightly gravelly) silty clay was encountered to depths of between 0.50m and 1.20m.

Dyrham Formation

This was underlain by stiff and very stiff orangish brown and bluish grey slightly cobbly silty gravelly becoming very gravelly clay, to depths of between 1.00m and 1.70m. With depth, this progressively became a (medium dense) orangish brown and bluish grey slightly clayey (slightly) silty gravel and cobbles to the base of the trial pits (depths of between 2.40m and 2.50m).

The density of the granular deposits was estimated from a visual assessment only, i.e. ease of excavation and stability of trial pit sides.

Estimates of undrained shear strength obtained from in-situ shear vane testing at a depth of 1.00m typically ranged between 80kN/m2 and 110kN/m2.

4.3 Groundwater

A very slight groundwater seepage was encountered at a depth of 1.30m (on the western wall) in SA2 only.



6

4.4 Soakaway Test Results

Full details of the soakaway testing results are provided in Appendix C of this report and are summarised in the table below:

Table 1: Summary of Soakaway Test Results

Test No. Total Recorded Fall of Water

Level (m)

Duration of Test (minutes)

Soil Infiltration Rate

(m/s)

SA1 0.03 307 n/a*

SA2 0.04 315 n/a*

SA3 0.00 320 n/a*

SA4 0.02 331 n/a*

* Test failed to reach 25% of the effective depth and so is deemed to have failed.



7

DISCUSSION OF RESULTS AND RECOMMENDATIONS

It is understood that soakaways are proposed as a means of surface water drainage for the residential development of land to the southeast of Foldhill Lane, Martock, Somerset. The proposed layout is presented in Appendix D of this report.

Negligible water level falls were recorded over the course of the day. All of the tests failed to reach 25% of the effective depth and are deemed to have failed.

On-site attenuation combined with off-site discharge is currently considered likely to be the most suitable drainage solution at this site.

The preferable drainage solution at this site would appear to be to discharge into the sewer or other suitable outfall. If necessary, an underground storage tank with a throttled outflow valve may be able to be installed to allow water to be discharged at an agreed rate so that during storm periods discharge is not increased from the present situation.



8

REFERENCES

• Building Research Establishment Digest 365 (2007): Soakaway Design.



9

TERMS AND CONDITIONS

1. This report has been prepared for the sole use of the specified client in response to an agreed brief and for the stated purpose. The recommendations used in this report should not be used for any other schemes on or adjacent to this site without further reference to this company.

2. The copyright of this report is owned by Ruddlesden geotechnical ltd. With the exception of the named client, who may copy and distribute the report to deal with matters directly relating to its commission, this report may not be reproduced, published or adapted without written consent of the company.

3. New information, improved practices and legislation may necessitate an alteration to the report in whole or in part after its submission. Therefore, with any change in circumstances, this report should be referred to Ruddlesden geotechnical ltd for reassessment and, if necessary, reappraisal.

4. The comments given in this report assume that ground conditions do not vary beyond the range revealed by the investigation. There may, however, be conditions at or adjacent to the site that have not been disclosed by the investigation and which, therefore, have not been considered in this report. Accordingly, a careful watch should be maintained during any future groundworks and the recommendations of this report reviewed as necessary.

5. Whilst confident in the findings of the report, the recommendations may not necessarily be accepted by other authorities without question. It is advisable that, where appropriate, the report be submitted to the relevant statutory authorities and approval obtained before detailed design, site works or other irrevocable action is undertaken.

6. All comments and recommendations are based on groundwater conditions encountered at the time of investigation. It should be noted that groundwater levels might fluctuate according to the season and from year to year. This may have implications on other recommendations, including foundations and excavations.

7. All third party data referred to in the report, e.g. environmental searches and laboratory testing, has been obtained in good faith from bona fide sources. Ruddlesden geotechnical ltd cannot be held liable for any incorrect information supplied to us.



APPENDICES



APPENDIX A

TRIAL PIT LOGS



Key to Trial Pit and Borehole Logs (Common Symbols)

Strata legend

Groundwater

Installations

Samples

D Small disturbed sample

J Small disturbed sample

(amber glass jar)

B Disturbed bulk sample

U100 Undisturbed sample (100mm

diameter)

W Water sample

In-situ testing

SPT Standard Penetration Test

(split spoon sampler)

SPT(C) Standard Penetration Test

(solid cone)

V Shear vane test

CBR California Bearing Ratio

Rotary drilling

TCR Total core recovery (%)

SCR Solid core recovery (%)

RQD Rock quality designation (%)

FI Fracture index (fractures/m)

NI Non-intact

SPT results (examples)

Made Ground

Topsoil Clay Silt

Sand

Gravel

Peat Composite soil types will be signified by combined symbols, e.g. silty sand

Chalk Limestone Coal Mudstone Siltstone Sandstone Fine grained igneous rock (e.g. basalt) Medium grained igneous rock (e.g. granite)

Fine grained metamorphic rock (e.g. slate)

Cement seal

Bentonite seal

Filter pack (slotted pipe)

Groundwater strike

Standing groundwater level

30 N-Value (blows recorded for 300mm penetration, following 150mm seating drive)

50/125 50 blows for 125mm penetration

SOIL GROUP Very coarse soils Coarse soils Fine soils

PRINCIPAL SOIL TYPE BOULDERS COBBLES GRAVEL SAND SILT

CLAY

Particle size (mm)

Large boulder Boulder Cobble Coarse Medium Fine Coarse Medium Fine Coarse Medium Fine

>630 630-200 200-63 63-20 20-6.3 6.3-2.0 2.0-0.63 6.3-0.2 0.2-0.063

0.063-0.02

0.02-0.0063

0.0063-0.002 <0.002

Visual identification

Only seen complete in pits or exposures. Difficult to recover whole from boreholes.

Easily visible to naked eye; particle shape can be described; grading can be described.

Visible to naked eye; no cohesion when dry; grading can be described.

Only coarse silt visible with hand lens; exhibits little plasticity and marked dilatancy; slightly granular or silky to the touch; disintegrates in water; lumps dry quickly; possesses cohesion but can be powdered easily between fingers.

Dry lumps can be broken but not powdered between the fingers; dry lumps disintegrate under water but more slowly than silt; smooth to the touch; exhibits plasticity but no dilatancy; sticks to the fingers and dries slowly; shrinks appreciably on drying usually showing cracks.

Density/ Consistency

No terms defined. Qualitative description of packing by inspection and ease of excavation.

Classification of relative density on the basis of N-value, or field assessment using hand tests may be made.

Term Very soft Soft Firm Stiff Very stiff

Field test

Finger easily pushed in up to 25mm. Exudes between fingers.

Fingers pushed in up to 10mm. Moulded by light finger pressure.

Thumb makes impression easily. Cannot be moulded by fingers. Rolls to thread.

Can be indented slightly by thumb. Crumbles in rolling thread. Remoulds.

Can be indented by thumb nail. Cannot be moulded, crumbles.

Discontinuities

Describe spacing of features such as fissures, shears, partings, isolated beds or laminae, desiccation cracks, rootlets, etc. Fissured: breaks into blocks along unpolished discontinuities. Sheared: breaks into blocks along polished discontinuities.

Scale of spacing of discontinuities

Term very widely widely medium closely very

closely extremely closely

Mean spacing (mm) >2000 2000-600 600-200 200-60 60-20 <20

Bedding

Describe thickness of beds in accordance with geological definition. Alternating layers of materials are inter-bedded or inter-laminated and should be described by thickness term if in equal proportions, or by a thickness of and spacing between subordinate layers where unequal.

Scale of bedding thickness

Term very

thickly bedded

thickly bedded

medium bedded

thinly bedded

very thinly

bedded

thickly laminated

thinly laminated

Mean thickness (mm)

>2000 2000-600 600-200 200-60 60-20 20-6 <6

Colour HUE can be preceded by LIGHTNESS and/ or CHROMA

Red/ Pink/ Orange/ Yellow/ Cream/ Brown/ Green/ Blue/ White/ Grey/ Black Light/ -/ Dark Reddish/ Pinkish/ Orangish/ Yellowish/ Brownish/ Greenish/ Bluish/ Greyish

Colours may be mottled More than 3 colours is multi-coloured

Secondary constituents

For mixtures including very coarse soils see section 33.4.4.2 of BS 5930 (2015).

Terms in coarse soils

slightly (sandy) B)

(sandy) B)

very (sandy) B)

SAND AND GRAVEL

Terms in fine soil

slightly sandy D)

(sandy) D)

very (sandy) F) Silty CLAY

Clayey SILT

Terms used to reflect secondary fine constituents where this is important

Proportion secondary A)

<5% 5-20% C) >20% C) About

50%

Proportion secondary A)

<35% 35-65% E) >65% E)

Mineralogy Terms can include: glauconitic/ micaceous/ shelly/ organic/ calcareous. For example: slightly (glauconitic)/ (glauconitic)/ very (glauconitic). Carbonate Content: slightly calcareous – weak or sporadic effervescence from HCl/ calcareous – clear but not sustained effervescence from HCl/ highly calcareous – strong, sustained effervescence from HCl. Organic soils contain secondary finely divided or discrete particles of organic matter often with distinctive smell, might oxidise rapidly. For example: slightly organic-grey/ organic–dark grey/ very organic–black

Particle shape Very angular/ Angular/ Subangular/ Subrounded/ Rounded/ Well-rounded A dominant shape can be described, for example: Cubic/ Flat/ Elongate

PRINCIPAL SOIL TYPE

LARGE BOULDERS BOULDERS COBBLES GRAVEL SAND SILT CLAY

Tertiary constituents

Example terms include: shell fragments/ pockets of peat/ gypsum crystals/ pyrite nodules/ calcareous concretions/ flint gravel/ brick fragments/ rootlets/ plastic bags. Qualitative proportions can be given: with rare/ with occasional/ with numerous/ frequent/ abundant. Proportions are defined on a site or material specific basis, or subjectively.

Geological unit

Name in accordance with published geological maps, memoirs or sheet explanations. For example: River Terrace Deposits/ Glacial Sand And Gravel/ Made Ground/ Crackington Formation/ Weathered Heavitree Breccia Formation/ Meadfoot Group/ Upper Devonian Slates/ Alluvium/ Topsoil/ Laminated Beds/ Bude Formation/ Sherwood Sandstone Group

A) Percentage coarse or fine soil type assessed excluding cobbles and boulders B) Gravelly or sandy and/ or silty or clayey

C) Can be described as fine soil depending on mass behaviour D) Gravelly and/ or sandy

E) Can be described as coarse soil depending on mass behaviour F) Gravelly or sandy

Field Identification and Description of Soils (Based on Table 7 of BS 5930: 2015)

1.00 VANE too stiff

TOPSOIL: Brown slightly gravelly silty clay with rare rootlets.

Firm to stiff orangish brown and bluish grey slightly gravelly silty CLAY. Gravel is fine tocoarse angular to subangular very weak mudstone (Head deposits).Very stiff orangish brown and bluish grey very thinly bedded slightly cobbly silty gravellyCLAY. Gravel and cobbles are fine to coarse angular to subangular mudstone and siltstone(Dyrham Formation).(Medium dense) orangish brown and bluish grey slightly clayey slightly silty GRAVEL andCOBBLES. Gravel and cobbles are fine to coarse angular to subangular very weak very thinlybedded mudstone and siltstone (Dryham Formation).

0.00-0.30

0.30-0.500.50-1.00

1.00-2.50

TRIAL PIT LOG

D

SAMPLES & TESTS

A

A B C

1 of 1

Legend

STRATADepth No Remarks/Tests

D B

TRIAL PIT No

Shoring/Support: None.Stability: Stable.Groundwater: None encountered.

0

1

2

3

4

5

6

0

1

2

3

4

5

6

DESCRIPTIONNoDepth

C

Co-Ordinates (BNG)

GENERALREMARKS

Sheet

Logged By

Project

1. Density of granular deposits estimated fromvisual assessment only.

Martock Farms Ltd

05-04-16

Foldhill Lane, Martock, Somerset

Method/ Plant Energy Ratio

Client:

16220

SA1

All dimensions in metresScale 1:75

Job No

E 346759 N 11951433.20

CG

Method/ PlantContractor

Ground Level (m)Date

JCB 3CX

Ruddlesden geotechnical ltdThe Stables, 65 Langaton LanePinhoe, Exeter EX1 3SPTelephone: 01392 678082

AG

S3

UK

TP

162

20 -

FO

LDH

ILL

LAN

E,

MA

RT

OC

K,

SO

ME

RS

ET

.GP

J A

GS

3_1

.GD

T 1

4/4

/16

0.70

2.90


Firm to stiff orangish brown mottled bluish grey silty CLAY (Head deposits).

Very stiff orangish brown and bluish grey silty very gravelly CLAY. Gravel is fine to coarseangular to subangular mudstone and occasional siltstone (Dyrham Formation).1.20 ...occasional cobbles(Medium dense) orangish brown and bluish grey slightly silty clayey GRAVEL and COBBLES.Gravel and cobbles are fine to coarse angular to subangular very thickly bedded mudstoneand occasional siltstone (Dyrham Formation).

0.00-0.40

0.40-0.80

0.80-1.40

1.40-2.50

TRIAL PIT LOG

D

SAMPLES & TESTS

A

A B C

1 of 1

Legend


D B

TRIAL PIT No

Shoring/Support: None.Stability: Stable.Groundwater: Very slight seepage from 1.30m (westerm wall only).

0

1

2

3

4

5

6

0

1

2

3

4

5

6

DESCRIPTIONNoDepth

C

Co-Ordinates (BNG)

GENERALREMARKS

Sheet

Logged By

Project


Martock Farms Ltd

05-04-16



Client:

16220

SA2


Job No

E 346836 N 11947334.50

CG



JCB 3CX


AG

S3

UK

TP

162

20 -

FO

LDH

ILL

LAN

E,

MA

RT

OC

K,

SO

ME

RS

ET

.GP

J A

GS

3_1

.GD

T 1

4/4

/16

0.70

2.00

1.00 VANE 80


Firm to stiff orangish brown mottled bluish grey silty CLAY (Head deposits).

0.85 ...clay pipe (50mm diameter)(broken)

Stiff orangish brown and bluish grey slightly gravelly silty CLAY. Gravel is fine to mediumangular to subangular mudstone (Dyrham Formation).1.50 ...very gravelly (fine to coarse) with occasional cobbles(Medium dense) orangish brown and bluish grey slightly silty clayey GRAVEL and COBBLES.Gravel and cobbles are fine to coarse angular to subangular very thinly bedded weakmudstone and occasional siltstone (Dyrham Formation).

0.00-0.40

0.40-1.20

1.20-1.70

1.70-2.50

TRIAL PIT LOG

D

SAMPLES & TESTS

A

A B C

1 of 1

Legend


D B

TRIAL PIT No


0

1

2

3

4

5

6

0

1

2

3

4

5

6

DESCRIPTIONNoDepth

C

Co-Ordinates (BNG)

GENERALREMARKS

Sheet

Logged By

Project


Martock Farms Ltd

05-04-16



Client:

16220

SA3


Job No

E 346842 N 11952436.00

CG



JCB 3CX


AG

S3

UK

TP

162

20 -

FO

LDH

ILL

LAN

E,

MA

RT

OC

K,

SO

ME

RS

ET

.GP

J A

GS

3_1

.GD

T 1

4/4

/16

0.70

2.00

1.00 VANE 110


Firm to stiff orangish brown mottled bluish grey silty CLAY (Head deposits).0.60 ...stiff

Stiff orangish brown and bluish grey slightly gravelly silty CLAY. Gravel is fine to mediumangular to subangular mudstone (Dyrham Formation).1.40 ...gravelly with occasional cobbles(Medium dense) orangish brown and bluish grey slightly silty clayey GRAVEL and COBBLES.Gravel and cobbles are fine to coarse angular to subangular very thinly bedded weakmudstone and occasional siltstone (Dyrham Formation).

0.00-0.40

0.40-1.20

1.20-1.70

1.70-2.40

TRIAL PIT LOG

D

SAMPLES & TESTS

A

A B C

1 of 1

Legend


D B

TRIAL PIT No


0

1

2

3

4

5

6

0

1

2

3

4

5

6

DESCRIPTIONNoDepth

C

Co-Ordinates (BNG)

GENERALREMARKS

Sheet

Logged By

Project


Martock Farms Ltd

05-04-16



Client:

16220

SA4


Job No

E 346845 N 11956337.50

CG



JCB 3CX


AG

S3

UK

TP

162

20 -

FO

LDH

ILL

LAN

E,

MA

RT

OC

K,

SO

ME

RS

ET

.GP

J A

GS

3_1

.GD

T 1

4/4

/16

0.70

2.00



APPENDIX B

PHOTOGRAPHS



Plate 1

The site, viewed from the northeast.

Plate 2

The west of the site, viewed from the southeast.



Plate 3

Ground conditions encountered in SA1.

Plate 4




Plate 5


Plate 6




APPENDIX C

SOAKAWAY TEST RESULTS


Soakaway Test ReportReport Ref: CG/JF/SR/16220/STR

Soakaway Test ResultsIn Accordance with BRE 365 "Soakaway Design"

Job Title:Job No.:

Client:Date:

Test No. SA1

Trial Pit DimensionsLength (m): 2.90Width (m): 0.70Depth (m): 2.50Start Water Level (m): 1.55Total Depth of Test 0.95

Field ResultsTime (minutes) Water Level (mBGL)

0 1.051 1.062 1.063 1.064 1.0621 1.0758 1.0795 1.07123 1.07160 1.07210 1.07255 1.08307 1.08

South of Foldhill Lane, Martock16220Martock Farms LtdApr-16




CalculationsSoil Infiltration Rate (f) = (Vp75-25) / (ap50 x tp75-25)

WhereVp75-25 = effective storage volume of water

in the trial pit between 75% and 25% effective depth

= 2.90 x 0.70 x 0.48

= 0.96425 m3

ap50 = internal surface area of the trialpit up to 50% effective depthand including the base area

= 0.67 + 2.76 + 2.03

= 5.45 m2

tp75-25 = time for the water level to fall from 75% to 25% effective depth25% effective depth = 1.787575% effective depth = 2.2625

= - mins

= 0 mins

= 0 secs

Soil Infiltration Rate (f) = (Vp75-25) / (ap50 x tp75-25)

= 0.96425 / 5.45 x 0

= #DIV/0! m/s

OTHER NOTES:



1.00

1.20

1.40

1.60

1.80

2.00

2.20

2.40

0 30 60 90 120 150 180 210 240 270 300 330

Wat

er L

evel

(m

BG

L)

Time (minutes)

Soakaway Test Results - SA1




Job Title:Job No.:

Client:Date:

Test No. SA2



0 1.001 1.022 1.023 1.034 1.035 1.0310 1.0423 1.0436 1.0561 1.05111 1.04149 1.04212 1.04258 1.04315 1.04








= 2.00 x 0.70 x 0.75

= 1.05 m3


= 1.05 + 3.00 + 1.40

= 5.45 m2


= - mins

= 0 mins

= 0 secs


= 1.05 / 5.45 x 0

= #DIV/0! m/s

OTHER NOTES:



1.00

1.20

1.40

1.60

1.80

2.00

2.20

2.40

0 30 60 90 120 150 180 210 240 270 300 330

Wat

er L

evel

(m

BG

L)

Time (minutes)





Job Title:Job No.:

Client:Date:

Test No. SA3



0 0.991 0.992 1.003 1.004 1.005 1.0017 1.0029 0.9945 0.9966 0.99118 0.99176 0.99215 0.99261 0.99320 0.99








= 2.00 x 0.70 x 0.76

= 1.057 m3


= 1.06 + 3.02 + 1.40

= 5.477 m2


= - mins

= 0 mins

= 0 secs


= 1.057 / 5.477 x 0

= #DIV/0! m/s

OTHER NOTES:



0.95

1.15

1.35

1.55

1.75

1.95

2.15

2.35

0 30 60 90 120 150 180 210 240 270 300 330

Wat

er L

evel

(m

BG

L)

Time (minutes)





Job Title:Job No.:

Client:Date:

Test No. SA4



0 0.971 0.972 0.983 0.994 0.995 0.9924 0.9934 0.9952 0.9971 0.99126 0.99174 0.99216 0.99264 0.99331 0.99








= 2.00 x 0.70 x 0.72

= 1.001 m3


= 1.00 + 2.86 + 1.40

= 5.261 m2


= - mins

= 0 mins

= 0 secs


= 1.001 / 5.261 x 0

= #DIV/0! m/s

OTHER NOTES:



0.95

1.15

1.35

1.55

1.75

1.95

2.15

2.35

0 30 60 90 120 150 180 210 240 270 300 330

Wat

er L

evel

(m

BG

L)

Time (minutes)




APPENDIX D

PROPOSED SITE LAYOUT

468 346900467

119600

195

194

N

Telephone (01747) 823232 Facsimile (01747) 825363Wessex House, High Street, Gillingham, Dorset SP8 4AG

DRAWING No.

DRAWING

DATE

SCALE REVISION

Chartered ArchitectsPlanning Consultants & Surveyors

BRIMBLE, LEA & PARTNERS Land adjacent to Triways,Foldhill Lane,Martock,Somerset.

26.02.201414022 - 2

SCALE IN METRES

LOCATION PLAN 1 : 2500

SCALING OF ELECTRONIC COPIESThis drawing should be printed at A4 Actual Size in order to be readat the stated scale of 1:2500Check scale bar to confirm printed scale before using any scale rule.

100 50 0 100 200 300

1: 2500 @ A4

B. 22.04.2014

Sketch illustrative site plan

Nursing home plan added.A. 03.02.2014REVISION

JL

H

Layout revised. JL

10 metre landscaping marginincorporating footpath includingnew hedge and tree planting tonew housing boundary

existing boundary hedgeretained and supplementedwhere necessary

area of landscapingand amenity space

copse planting

existing boundary hedge retained andsupplemented where necessary includingreinforcement with tree planting

existing hedgetranslocated wherenecessary forvisibility

Layout revised, landscaping. JLC. 29.05.2014RRLayout revised, landscaping.D. 30.05.2014

E. 09.06.2014 Layout revised, landscaping. JL

39

40

38

37

36

35

34

41

Contour study.F. 12.08.2014 JL

33

Layout revised, landscaping.G. 02.09.2014 JLLayout revised, landscaping.H. 19.02.2015 RC



APPENDIX E

SOAKAWAY TEST LOCATION PLAN

TP01 TP101

WS1 WS01

BH01

DCP1

BH1

WS101

BH101SA2

SA3

SA4

The Stables65 Langaton Lane

Pinhoe ExeterEX1 3SP

www.ruddlesden.co.uk

Job Title:

Drawing Title:

Client:

Dwg No:

Date:

Scale:

NTS

APR-16

16220/02

MARTOCK FARMS LTD

SOAKAWAY TEST LOCATION PLAN

FOLDHILL LANE, MARTOCK, SOMERSET

TP1

LEGEND

Soakaway Test

SA1


Issue 1 June 2016


Appendix F: Surface Water Drainage Calculations

Surface Water Drainage Calculation Record

Project Number: C1579 Nation Grid Reference: ST 45000 19700

Project Name: Foldhill Lane Catchment ID: N/A

Climate Change Allowance: 40%

Site Input Data

Total Area: 1.57 ha SAAR: 758

Existing Imp. Area: 0.00 ha BFIHOST: 0.557

Proposed Imp. Area: 0.69 ha SPRHOST: 36.22

Hydrological Region: 8 SPR: 0.36

Greenfield Runoff Estimation

Q MED = 8.3062AREA 0.8510 x 0.1536 (1000/SAAR) x FARL 3.4451 x 0.0460 BFIHOST^2 = 149.62 l/s

where AREA = 0.5 km2

Q bar conversion ratio = 1.075 Qbar = 160.84 l/s

Divide by 50 ha to determine l/s/ha for development site: 3.22 l/s/ha

Growth Curves obtained from FSSR 14

1 in 1 year (Q 1 ): 2.5 l/s/ha 1 0.78

1 in 30 year (Q 30 ): 6.3 l/s/ha 2 0.88

1 in 100 year (Q 100 ): 7.8 l/s/ha 25 1.84

30 1.95

1 in 100 year runoff volume 50 2.12

100 2.42

PRRURAL = SPR + DPRCWI + DPRRAIN 200 2.74

where: DPRCWI = 0.25(CWI-125), where CWI is a function of SAAR;

DPRRAIN = 0.45(P-40)0.7 for P > 40 mm; or

DPRRAIN = 0 for P ≤ 40 mm where P is rainfall depth.

30 minute storm (V 30 min ): 129.3 m3/ha (rainfall depth of 39.4 mm)

6 hour storm (V 6 hr ): 318.7 m3/ha (rainfall depth of 81.8 mm)

Existing Site Runoff Rates and Volumes

Q1 (l/s) Q30 (l/s) Q100 (l/s) V30 min (m3) V6 hr (m

3)

Permeable Element 3.9 9.8 12.2 203.0 500.4

Impermeable Element 0.0 0.0 0.0 0.0 0.0

Total 3.9 9.8 12.2 203.0 500.4

Permeable element as per greenfield calculations above and impermeable elements calculated using the Modified Rational Method.

Post-development Runoff Rates (without mitigation)

Q1 (l/s) Q30 (l/s) Q100 (l/s) V30 min (m3) V6 hr (m

3)

Permeable Element 2.2 5.5 6.9 113.8 280.5

Impermeable Element 21.3 106.8 152.4 274.2 569.2

Total 23.5 112.3 159.3 388.0 849.7

Return

Period

Growth

Factor

SuDS Calcs - Foldhill Lane.xlsx 1 22/06/2016

Flow control rates for site

Q1: 2.7 l/s

Q30: 3.3 l/s

Q100: 3.3 l/s

Storage Estimation

Interception Storage Long Term Storage

5 mm X 0.69 ha = 34.5 m3849.6 - 500.3 = 349.2 m3

Attenuation Storage

15 32.2 -72.72 -75.70

30 39.4 -3.17 -9.13

60 48.3 82.80 70.88

120 59.2 188.10 164.25

240 72.6 317.54 269.85

360 81.8 406.41 334.87

720 100.2 584.16 441.08

1440 114 717.46 431.31

2880 129.7 869.13 296.81

Total Required Storage = 824.9 m3

SuDS Elements

Bioretention Areas30 m2 of area offering 0 m3 of storage volume

Permeable paving40 m2 of area offering 0 m3 of storage volume

Swales/Ditch Feature5100 m of length offering 852 m3 of storage volume

Ponds/Basins60 m2 of area offering 0 m3 of storage volume

Geo-cellular Storage70 m2 of area offering 0 m3 of storage volume

Total 852 m3 of storage volume

1. Rainfall Depth multiplied by storm duration minus Interception Storage and LTS.

2. Average outflow rate (mean of Q1 and Q100) multiplied by storm duration.

3. Based on a porous depth of 0.5 m with a void space of 30% and a freeboard of 0.1 m.

4. Based on a porous depth of 0.75 m with a void space of 30%.

5. Based on a width of 3.5 m with a depth of 120% and side slope of 1 in 3.

6. Based on an average storage depth of 1 m.

7. Based on a storage depth of 0.5 m with a void space of 95%.

181.58

286.16

572.31

Rainfall Depth

+ CC (mm)

Rainfall

Duration (min)

Rainfall

Depth (mm)

11.92

45.08

55.16

67.62

2.98

5.96

Net Inflow

Volume (m3)

1

Outflow

Volume (m3)

2

Based on the first 5 mm of rainfall to intercept

the first flush of runoff, which contains the

majority of pollutants.

The difference between the pre-development

and post-development runoff rates to be stored

on site (design to be confirmed).

These are discharge rates for the proposed

impermeable areas of the site only.

Attenuation

Volume (m3)

159.6

23.85

47.69

71.54

143.08

82.88

101.64

114.52

140.28

SuDS Calcs - Foldhill Lane.xlsx 2 22/06/2016


Issue 1 June 2016


Appendix G: SuDS Maintenance Schedule


Issue 1 June 2016


Table G1: Swale Operation and Maintenance Requirements

Schedule Required Action Frequency

Regular maintenance

Remove litter and debris. Monthly, or as required.

Cut grass – to retain grass height within specified design range.

Monthly (during growing season), or as required.

Manage other vegetation and remove nuisance plants.

Monthly at start, then as required.

Inspect inlets, outlets and overflows for blockage, and clear if required.

Monthly.

Inspect infiltration surface for ponding, compaction, silt accumulation, record areas where water is ponding for >48 hours.

Monthly, or when required.

Inspect vegetation coverage. Monthly for 6 months, quarterly for 2 years, then half yearly.

Inspect inlets and facility surface for silt accumulation, establish appropriate silt removal frequencies.

Half yearly.

Occasional maintenance

Reseed areas of poor vegetation growth, alter plant types to better suit conditions, if required.

As required or if bare soil is exposed over 10% or more of the swale treatment area.

Remedial actions

Repair of erosion or other damage by reseeding or re-turfing.

As required.

Relevel uneven surfaces and reinstate design levels

As required.

Scarify and spike topsoil layer to improve infiltration performance, break up silt deposits and prevent compaction of the soil surface.

As required.

Remove build-up of sediment on upstream gravel trench, flow spreader or at top of filter strip.

As required.

Remove and dispose of oils or petrol residues using safe standard practices.

As required.

Inspect inlets and facility surfaces for silt accumulation. Establish appropriate silt removal frequencies.

Half yearly.

appendix e: soakaway tests -...

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