appendix e - groundwater drainage and irrigation construction

Groundwater drainage and irrigation construction -

general scope of works for the nursery site at

Hyde Park

Ref. 200.D2

24th May 2016

Shackerdale Farm � Car Colston � Nottinghamshire � NG13 8JB

+44 (0) 7904 526307 � [email protected].

Ref. 200.D2 The Royal Parks – Groundwater drainage and irrigation provisional construction scope 24.05.16 2 of 9

Contents

1.0 Introduction

1.1 General

1.2 Drawing Register

2.0 Works

2.1 Modification of works carried out during the demolition phase,

including acting upon additional findings within the demolition phase in

order to achieve the full design intent

2.1.1 Basement sump chamber to MH 082

2.1.2 Works at MH082

2.2 Conversion of MH052 to an abstraction pumping chamber

2.3 Installation of abstraction pump and controls for transferring water to the

irrigation storage tank

2.4 Irrigation storage tank

3.0 Materials specification (guidance only)

3.1 Polyethylene pipe work

3.2 Structured wall pipe (TwinWall)

3.3 Chambers

3.4 Concrete, bricks & blockwork & mortar

3.5 Backfill of chambers and of trenching


1.0 Introduction

1.1 General

This component of the scoping for the Hyde Park Nursery Construction Package covers the

following:

1. Modification of works carried out during the demolition phase, including acting upon

additional findings within the demolition phase in order to achieve the full design

intent

2. Conversion of MH052 to an abstraction pumping chamber

3. Installation of abstraction pump and controls for transferring water to the irrigation

storage tank

4. Irrigation storage tank

This document should be read and understood together with the ‘Groundwater drainage and

irrigation demolition scope of works in preparation for reconstruction of the nursery site at

Hyde Park’ (16th May 2016). This includes any modifications to his scope necessary owing to

findings within the review stage of the demolition works or afterwards.

NB. Deep channels and drains are sized 6”, not 8” as indicated in the above previously issued

demolition package.

1.2 Drawing Register

The drawings listed in italics are issued with the demolition (Phase 1) package. The drawings

listed in bold are new with this document.

Dwg. No. Title Size Date Rev

200.HND.01 Known Groundwater Chambers – information

only A3 16.05.16 1

200.HND.02 New chamber for temporary pumping at the

basement sump A3 16.05.16 1

200.HND.03 General basement sump chamber plan A3 16.05.16 1

200.HND.04 Inside basement sump A3 16.05.16 1

200.HND.05 Inside MH082 & MH052 A3 16.05.16 1

200.HND.06 Conversion of basement sump to gravity flow A3 24.05.16 1

200.HND.07 Conversion of MH052 to abstraction chamber A3 24.05.16 1

200.HND.05 Provisional irrigation storage tank location A3 24.05.16 1


2.0 Works

2.1 Modification of works carried out during the demolition phase, including acting

upon additional findings within the demolition phase in order to achieve the full design

intent

The full outcome of this part of the works is not yet known but is likely to include the

following:

2.1.1 Basement sump chamber to MH 082

A. See Dwg. No. 200.HND.06 ‘Conversion of basement sump to gravity flow’.

To 2m stub of 225mm unperforated TwinWall pipe laid at approximately 17.75m,

extend this pipe to location of MH082. The pipe is to be laid level or with a nominal

fall. This will depend on exact levels encountered during the survey and review of

the groundwater drainage system and thus is subject to change.

NB: The intention is that all water that finds its way into the basement sump

chamber, continues to do so, but by gravity runs towards the existing MH082 and

thence to MH052

B. As an alternative to the route described above and shown on the drawing, a more

direct route may be taken directly from the site of the basement sump chamber to

the site of MH052, bypassing MH082

2.1.2 Works at MH082

A. MH082 (see Dwg. No. 200.HND.D.05 ‘Inside MH082 & MH052’ and Dwg. No.

HND.200.D.01 ‘Known Groundwater Chambers – information only’) is known to

convey water from MH051 to MH052. There is a connection between MH082 and

the basement sump chamber. Its condition is dubious and there is an extensive

vault / culvert beneath the top of MH082 which includes timber walling / shuttering

etc.. It is proposed that this chamber be removed and a new one installed.

B. The new chamber shall include a 600mm sump below the lowest invert. The lowest

invert is anticipated to be the outgoing drain. However, this is not confirmed and

the precise works in this area are subject to review.

C. See plates 1 & 2 below


Plate 1: Taken from within MH082 looking south

Plate 2: Taken from within MH082 looking south


2.2 Conversion of MH052 to an abstraction pumping chamber

A. MH052 (see Dwg. No. 200.HND.1 ‘Known groundwater chambers - information

only’) is the final (known) confluence of all groundwater drainage channels at the

nursery site. The current invert, upon a main channel bend, is 17.31m. It is

proposed that this MH052 be completely rebuilt.

B. The chamber shall be constructed of DN1500 concrete rings – or as otherwise

proposed by the D&B contractor) with a closed sump of 2m below the lowest pipe

invert level

2.3 Installation of abstraction pump and controls for transferring water to the irrigation

storage tank

A. The existing pump within the newly constructed basement sump chamber shall be

relocated to this new abstraction chamber. See Dwg. No. 200.HND.D.07

‘Conversion of MH052 to abstraction chamber’

B. A power supply shall be available approximately as shown on Dwg. No.

200.HND.D.06 ‘Conversion of basement sump to gravity flow’. This will have been

installed as part of the Phase 1 Demolition works and is shown also on Dwg. No.

200.HND.D.03 ‘General basement sump chamber plan’

C. Between the abstraction chamber (MH052) and the irrigation storage tank shall be

installed a new 90mm SDR100 black PE100 rising main at c. 1m depth.

D. With the rising main shall be sited 2 No. 100mm smooth-bore flexiduct suitable for

carrying pump start / stop signal components and for future unspecified uses

2.4 Irrigation storage tank

A. Approximately as shown on Dwg. No. 200.HND.D.8 ‘Provisional irrigation storage

tank location’ shall be sited the irrigation storage tank.

B. This shall be a durable glass-lined steel tank (or as approved) and hold a working

capacity of 150m3.

C. The tank shall be completely above ground unless as otherwise agreed

D. It shall be fitted with 2 No. DN90 stainless steel risers and 1 No. DN150 stainless

steel riser for incoming water (potable, groundwater, borehole) plus all other

connections for level control and indication

E. It shall be fitted with 1No. DN100 low level tank outlet


3.0 Materials specification (guidance only)

3.1 Polyethylene pipe work

PE pipe work shall be as follows:

· Black

· SDR17 or 11 as described

· PE100

· Manufactured to EN 12202

· Joints: � 50mm – 90mm electrofusion only � 110mm (Lift pump) butt-welded and reamed sticks only � 110mm electrofusion � 160mm electrofusion

· Where compression fittings are used to connect to the pump set steelwork, Plasson,

Philmac or other approved manufacturer shall be used.

3.2 Structured wall pipe (TwinWall)

TwinWall pipe as detailed within the tender drawings and this specification shall be a

structured wall, thermoplastic, twin-extrusion pipe manufactured from High Density

Polyethylene or Polypropylene. This material specification shall also apply to the Rigi-duct.


3.3 Chambers

Precast concrete manhole chambers: made to BS EN 5911-3 and BS EN 1917 sized at

DN1200 and DN1500.

Manufacturers to be approved prior to installation.

Where instructions and specifications are not given which are contrary to the Manual of

Contract Documents for Highway Works Volume 1 – Specification for Highway Works, Series

500, Clause 507, the Manual of Contract Documents for Highway Works shall be followed.

This includes method of laying and penetrations.

Concrete chambers shall be installed upon ST1 C25 concrete with a minimum depth of

200mm.

Note that pre-fabricated chambers may be suitable but should be approved at tender stage.

All chamber lids (including replacement lids) shall be D400. The decision on which lids might

need replacement owing to age and condition shall be made by the contractor and fully

costed. The necessary condition survey as part of this work may also dictate the necessity

for one or more of the chambers’ risers, i.e. not just MH082 and MH052 to have their upper

portions remade.

3.4 Concrete, bricks & blockwork & mortar

Where instructions are not given which are contrary to the Sewers for Adoption 6th Edition,

Part 5 – Civil Engineering Specification, the Sewers for Adoption 6th Edition, Part 5 – Civil

Engineering Specification shall be followed.

All concrete shall follow the specifications within the following standards:

BS EN 206-1 Concrete – Part 1: Specification, performance, production and conformity

BS 8500-1 Concrete – Complementary British Standards to BS EN 206-1. Part 1: Method for

specifiying and guidance for the specifier

BS 8500-2 Concrete - Complementary British Standards to BS EN 206-1. Part 2.

Specifications for constituent materials


The supply of ready-mix concrete shall be via a plant which is approved by a Third Party

Certification Body accredited under Category 2 (Product Conformity) by the National

Accreditation Council for Certification Bodies.

All cement shall be sulphate resisting Portland Cement complying with the provisions of BS

EN 197-1. Mortar shall be mixed on site – away from the Fleet Brook - as required and shall

comply with the requirements of BS EN 998-1 and BS EN 998.2

All bricks used below ground or as part of a below ground structure shall be Class B

Engineering bricks complying with the relevant provisions of BS 3921 and shall be F-

Category frost resistant.

3.5 Backfill of chambers and of trenching

It is anticipated that existing arisings may be used for the backfilling of trenches but the

contractor shall allow for blinding if required. The minimum standards for backfilling of

trenches are as included within the ‘Specification for Highway Works Series 500’ with

materials complying with either Table 5/3 ‘BS EN 13242, Coarse aggregate for pipe bedding,

haunching and surrounding material’, clause 4.3.2, or Table 5/4 ‘BS EN 13242, Fine and all-

in aggregated for pipe bedding, haunching and surrounding material’ clause 4.3.3.

The fill and compaction methodology for the basement shall be provided by the structural

engineers. It is anticipated that this shall include reference to ‘Specification for Highway

Works Series 600’ and in particular clause 608 – 612.

Notes

Blue arrows show approximate route of piped groundwater.

The information that this drawing carries remains the property of Irriplan Ltd. This drawing is protected by copyrightand may not be reproduced, copied or used for any purpose without the written consent of Irriplan.

1:125Scale: Drawing No:Date:Drawn By:WW

Ver. No:

1Client: Drawing Title: Project:

Shackerdale Farm, Car Colston, Nottinghamshire. NG13 8JB UKwww.irriplan.net

Irrigation Drainage Water Resources Reservoirs

Conversion of basementsump to gravity flow

The Royal Parks 200.HND.D.0624.05.16Nursery Redevelopment

This drawing shows the installation of a new 225mmunperforated TwinWall pipe to connect to a length ofexisting TwinWall (to be installed as part of theDemolition package) and taken to MH082. This pipe is tobe laid level or, if possible with a nominal fall, and theselevels are to be determined and agreed on site.

MH082 is to be completely reconstructed using DN1500sealed concrete rings above whatever base is required toenable water to be received into the chamber from thebasement sump chamber, from chamber MH051 and anyfrom any other incoming chamber/pipe by gravity. Thereconstructed MH082 is to be fitted with a sump ofminimum 600mm below the lowest invert. Water will begarvity fed to chamber MH052 via existing or renewedpipe work as determined at Phase 1 (Demolition) .

MH052 is to be completely reconstructed using DN1500sealed concrete rings. This is to include a completereconstruction of the bed of the chamber and allincoming drain entries and exits. See Dwg. No.200.HND.D.07. This will become the new abstractionchamber.

Notes

This drawing is schematic and except for the general evelations is not to scale.All details are too beconfirmed prior to construction. The pump installed within the basement sump chamber on atemporary basis for Phase 1 is to be permanantly moved to this new MH052 for Phase 2, followingfinal clarification of distance and lift.



Ver. No:




Conversion of MH052 toabstraction chamber


Notes

This drawing is for guidance only for tendering and is not for construction.



Ver. No:




Provisional irrigationstorage tank location


Groundwater shall be collected from the BasementSump Chamber, MH082 (which are North ofMH052) and also from West of MH052. This shallall be by gravity.

MH052 shall be converted to a new abstractionchamber.

From this new abstraction chamber water will bepumped to a new irrigation tank.The initial suggested location of the irrigationstorage tank is approximately as shown.It shall be wholly above ground and hold aworking capacity of 150m³.