MD1483 Dagenham Dock foul water infrastructure upgrade

Type of decision: 
Mayoral decision
Code: 
MD1483
Date signed: 
26 March 2015
Decision by: 
Boris Johnson MP (past staff), Mayor of London

Executive summary

A foul water drainage infrastructure upgrade is urgently required - up to a maximum expenditure of £1,000,000 to address flooding and network capacity issues caused by outdated and underspecified infrastructure inherited by GLA Land and Property (GLAP) in Dagenham Dock. 

 

 

Decision

That the Mayor approves expenditure, of up to a maximum of £1,000,000, in respect of an urgent drainage infrastructure upgrade in Dagenham dock. 

 

 

Part 1: Non-confidential facts and advice

Introduction and background

1.1    The Greater London Authority holds significant land assets in the Dagenham Dock area, including land assembled for the flagship London Sustainable Industries Park (LSIP).  Much of the infrastructure that serves this land was inherited by GLAP from the London Thames Gateway Development Corporation and from the London Development Agency.

1.2        The Mayor has previously approved an upgrade to the existing foul water infrastructure serving the LSIP as part of the main works package. The need to upgrade the network to cope with the peak wastewater outflows from the individual plots has also been reported to both HIG and to IPB. This is budgeted for and GLA officers have appointed consultant engineers to advise on delivering the upgrade. 

1.3        Outside of the LSIP, GLAP owns a pumping station in Halyard Street (close to the corner with Choats Road).  This pumping station serves several businesses in the Dagenham Dock area, including Closed Loop Recycling.  This pumping station is old, under-sized and does not provide suitable resilience to the business at Dagenham Dock.  The sewer main that takes effluent from the pumping station to the main Thames Water outfall sewer has shown that this too is not fit for purpose.

1.4        On several occasions during the autumn/winter 2014/2015, the pumping station and the sewer have become blocked and have severely limited the ability by local businesses to discharge foul water.  As GLAP owns the pumping station, the Authority is responsible for providing adequate drainage and could be liable for costs of disposing of foul water if its obligations are not met.    

1.5        GLA estates officers have instigated a programme of emergency flood mitigation measures, including disposal of excess water by tanker, flushing of the sewer network and the installation of rodding points to allow access to the sewer main.

 

Objectives and expected outcomes

2.1    As mentioned in the introduction, GLA estates officers have sought to implement temporary solutions to address the ongoing problems at Dagenham Dock.  Given the age and capacity shortfall in the existing infrastructure, it is clear that the network and pumping station need to be upgraded or replaced, particularly as the pace of development in the surrounding area increases.

2.2    The temporary measures have significant ongoing cost implications and, coupled with the risk of claims from local businesses unable to use the network because of flooding, it is clear that providing an upgrade to the infrastructure should be delivered as soon as possible.

2.3    As part of the ongoing infrastructure work to the LSIP project site, engineers have designed a new pumping station to cater for the foul water capacity upgrade needed to accommodate discharge from the tenants of the park.  GLAP has a contractual obligation to deliver the upgrade and so sewer designs have progressed and a planning application has been submitted for the pumping station.

2.4    There is potential for the proposed new pumping station and network on the LSIP site to be enlarged and upgraded to provide additional capacity for business in the wider area, removing the need to replace GLAP’s network at Dagenham Dock.  The solution would take discharge from business south of Choats Road and pump through a new larger sewer to the Thames Water main.

2.5    GLA officers have commissioned a detailed study of existing and future discharge rates and have concluded that delivering this upgraded solution would meet the needs of business in the local area, removing the risk to GLA brought about by continued use of existing inadequate infrastructure.

2.6    The LSIP already has an approved budget for construction of a new pumping station and sewer on the LSIP north site.  This budget is insufficient however to deliver the larger capacity solution. The upgraded solution requires a larger well, sewer main, pumps and an expansion of the network to link business to the south of the park into the new pumping station.

2.7    The GLA’s consultants have indicated that the larger capacity solution could be delivered by the end of 2015.  Clearly, the GLA will need to continue to monitor the existing network while the new facility is under construction.  This will mean regular clearing, rodding of blockages, overpumping and tankering of excess effluent where necessary.  The additional expenditure requested in this paper covers the additional cost of providing the larger capacity system and the potential expenditure on temporary flood prevention until the new system is brought into use.

2.8    It is recommended that GLAP proceed with the implementation of the new higher capacity foul water drainage infrastructure upgrade.  The budget requested will allow GLAP to:

•    facilitate increasing capacity of the proposed pumping station on the LSIP site
•    upgrade the local sewer network to provide increased capacity
•    implement temporary measures to prevent flooding caused by outdated GLAP infrastructure, including overpumping  and tankering of foul water
•    carry out emergency repairs and maintenance to the GLAP owned pumping station and sewer network

2.9    The works package to deliver the larger capacity system will be procured through a competitive tendering process overseen by GLA officers and the GLA’s appointed project managers Turner and Townsend.  GLA officers are working closely with Transport for London procurement colleagues to produce a procurement strategy that will set out how a works contractor will be engaged. The procurement will be undertaken in accordance with the GLA’s Contracts and Funding Code.

 

Equality comments

3.1    There are not considered to be any implications for equality monitoring as a result of this request for additional expenditure.

 

Other considerations

4.1    As mentioned earlier in the paper, GLAP has a contractual obligation to upgrade the foul water network on LSIP north to cater for new tenants of the park. These obligations were entered into as a condition of sale and enabled the GLA to secure hundreds of millions of investment in green technology and extensive job creation in clean tech industry, as well as a market tested land receipt.   If the foul water upgrade is not delivered within an agreed period, the GLA will become liable for the costs of disposal of trade effluent from tenants.

4.2    The GLA is under pressure to commit to a design for the new pumping station and network and any further delay in selecting a preferred option (either the existing budgeted proposal for LSIP or the higher capacity network) will start to put pressure on the programme for installation of the infrastructure.  Delays caused by necessary investigations into the cause of the Dagenham Dock network problems have compounded the issue.

4.3    There are risks associated with proceeding with the higher capacity system.  These are outlined below:

•    GLA has submitted a planning permission for the smaller capacity system.  This will need to be amended to show the deeper well and revised surface layout as a non-material amendment post resolution.
•    In order to provide the higher capacity for the wider area, the well needed for the proposed system is much deeper, potentially opening up the risk of encountering ground condition issues.  The additional expenditure requested will allow a concrete footer to be built to stabilise the shaft.
•    Thames Water has given its initial approval to the designs for the smaller system.  Approval will need to be sought for the larger system, although this is considered to be a manageable risk, due to the design being of an adoptable standard.

4.4    The GLA has sought to minimise risk more generally through employing an experienced engineering consultant with detailed knowledge of the LSIP site.  BHA has provided initial designs for both solutions, has provided a scope of works to GLA project managers and has advised on a planning solution for the larger capacity proposal.  Costs of construction have been checked in the market against ongoing similar projects and are considered a fair reflection of the risks identified.

 

Financial comments

5.1    Approval is sought for additional capital expenditure of £1,000,000 in GLAP to address the upgrade required to the Dagenham Dock foul water infrastructure, as detailed in the body of this decision, and will be funded from GLAP capital receipts.

 

Investment and Performance Board

7.1    This is an urgent request for additional funds to deal with an ongoing problem and as such this paper has not been discussed at IPB or HIG.

7.2    As mentioned above, there is IPB and HIG approved budget provision for a smaller local network to be provided on LSIP north.  The additional expenditure will allow GLAP to expand that provision to cover the wider area and remove the existing under capacity pumping station and network from service.

 

Planned delivery approach and next steps

Activity

Timeline

Approval of MD

w/c 23rd March

Work on finalising larger capacity solution commences

w/c 23rd March

New network complete and operational

December 2015

Existing network taken out of service

January 2016

Network adopted by Thames Water

Est 2017

 

Appendices and supporting papers

BHA technical note (Appendices A-E)