Case Studies
Contents Flood Risk Code for Sustainable Homes Preliminary Drainage Assessment Flood Risk Assessment - Flood Zone 3 Flood Risk Assessment - Flood Zone 1 (>1Hectare)
3 4 5 6
Hydraulic Modelling Breach Assessment Coastal Breach Assessment River Modelling Flood Zone Reclassification & Hazard Mapping Flood Consequences & Solution Assessment
7 8 9 10 11
Water Supply Design
12
Asset Security
13
Case Study Code for Sustainable Homes Sur 1 and Sur 2 Residential Development
Litten Terrace, Chichester ▪ Residential Development - Code Level 3 ▪ Partially within Flood Zone 2 ▪ Increase in Impermeable Area ▪ Surface water run-off calculations ▪ Sur 1 Template ▪ Mandatory Flood Risk Assessment
Scheme Waterco was instructed to carry out a Flood Risk Screening Study and Surface Water Run-off Appraisal to satisfy the mandatory elements of Sur 1 & Sur 2 of the CSH for a proposed residential development in Chichester. The development comprised 6 properties located partially within Flood Zone 2 as shown on the Environment Agency (EA) Flood Map.
Outcomes and Solutions An FRA screening study was carried out in accordance with National Planning Policy Framework (NPPF). This investigated all possible sources of flooding which could affect the site. This included: fluvial, groundwater, surface water, sewers and artificial flooding.
Objectives Satisfy the mandatory elements and evidence under Category 4 of the CSH: Surface Water Run-off, Code issues Sur 1 and Sur 2. As the development would increase the impermeable area of the site, surface water run-off rate and volume calculations were needed to address the mandatory requirements of Sur 1. A Flood Risk Assessment (FRA) was needed to satisfy the mandatory evidence under Sur 1 and possibly achieve two Sur 2 credits.
A detailed study of the West Sussex Strategic Flood Risk Assessment (SFRA) was conducted. This study found that detailed flood modelling has been conducted as part of the SFRA which showed that the site was not located within Flood Zone 2. The site was found to be at risk of groundwater flooding. It was recommended that finished floor levels were raised at least 150mm above surrounding ground levels to reduce the risk of groundwater flooding. Therefore the development was able to achieve the two Sur 2 credits. Surface water run-off calculations were carried out to assess the run-off rates and volumes for the pre and post-development situation. In accordance with NPPF a 30% allowance for climate change was included for the post development situation. The Sur 1 template was completed with the results of the calculations. The developer stated that soakaways and a green roof would be used to dispose of surface water. Therefore our report advised that the development would be entitled to the maximum two Sur 1 credits available.
01824 702220, www.waterco.co.uk, enquiries@waterco.co.uk Waterco Ltd. Eden Court, Lon Parcwr Business Park, Ruthin, Denbighshire, LL15 1NJ
Case Study Preliminary Drainage Assessment Code For Sustainable Homes (CSH)
Trefnant, Denbighshire Ÿ Analysis of Impermeable and Permeable Surfaces Ÿ IOH 124 + Rational Method Runoff Calculations Ÿ Site Visit Ÿ Arrange, Oversee and Analyse Percolation Test Ÿ Agree discharge rates with the Environment Agency Ÿ Multi-disciplinary Team Meeting Ÿ Flood Risk Assessment Ÿ Recommend Foul Sewerage Solutions
Objectives Waterco recommended that a full Preliminary Drainage Assessment be carried out as its recommendations would satisfy both the planning requirements and future CSH requirements of the development. This method of working produced cost effective results for the client by identifying the solutions and constraints to the team, before submitting the Planning Application. We have worked with Waterco on a number of projects and always found them to be proactive and responsive. In particular, on the Bryn Glas project in Trefnant, we found it beneficial to bring them on board at the beginning of the project in order that we could determine the flooding and drainage strategy as this would heavily influence the layout.”
Scheme Outline Planning Permission was sought for a residential development on partially Greenfield land. An existing dwelling was to be demolished as part of the scheme. As Code for Sustainable Homes (CSH) was a new requirement the client’s Architects wanted to ensure that the scheme would be designed with CSH in mind.
Outcomes and Solutions Foul Water Dŵr Cymru Welsh Water (DCWW) was contacted to supply the existing drainage records. As the site sloped away from the sewers, a full gravity fed sewerage system would not be feasible. Waterco recommended that a sewage pumping station would be required and as a result no houses could be located within 15m of the Pumping Station. By advising the Architect on the layout and location constraints, the layout was revised before the Planning Application was submitted and it still accommodated all 16 houses. Surface Water Percolation tests were carried out, and 3 out of 4 of the tests were unsuccessful. Calculations were required to assess the change in the rate and volume of run-off, as the development increased the amount of impermeable surface on site. Part H of the Building Regulations requires developments to discharge surface water by infiltration, i.e. Soakaway where possible. As the percolation test proved that this method would only be viable for part of the site, Waterco liaised with the Environment Agency to establish an agreement in principle for discharge of attenuated water into a brook within the site. Code for Sustainable Homes Our report will enable the future project to achieve the mandatory elements and evidence for the design stage of Sur 1 and Sur 2. A Flood Risk Assessment was completed and showed that the site was not at risk of flooding, and therefore qualified for two Sur 2 Credits.
- Matt Jones, Tarmaster Jones
01824 702220, www.waterco.co.uk, enquiries@waterco.co.uk Waterco Ltd. Eden Court, Lon Parcwr Business Park, Ruthin, Denbighshire, LL15 1NJ
Case Study Flood Risk Assessment Flood Zone 3
Outdoor Activity Centre Winsford, Cheshire ● Flood Risk Assessment for development in Zone 3 ● Water-Compatible Development ● Consultation with Environment Agency ● Evaluation of Flood Levels to inform the design phase and deliver cost benefit
Scheme Full planning permission was sought for a proposed recreational development at The Marina Outdoor Activity Centre, Winsford. The proposed development was shown on the Environment Agency Flood Map as in Flood Zone 3. The development was classified under *PPS25 as a ‘water-compatible’ development. An additional factor in this scheme was a funding application to Sports England, which meant that in order to meet their funding programmes tight deadlines had to be met. Waterco was engaged to evaluate the flood risk to the site and prepare a Flood Risk Assessment within these deadlines.
Objectives To provide a qualitative appraisal of flood risk posed to the site and the potential impacts the development would have elsewhere. Engage and consult with statutory authorities to ensure principles and recommendations were appropriate and compliant with current legislation and strategies. Ensure that risks identified could be effectively mitigated through good design. Partnership working with client and design team to ensure both services and proposed design solutions deliver cost effective solutions.
Outcomes and Solutions The development was justified as activities on the site and river were to be recreational and it was reasonable to assume that during extreme weather conditions or flooding that no one would be using the site for such activities. We were able to confirm through consultation with the Environment Agency that the sequential test did not need to be applied, as the development was considered appropriate. Our client provided us with a topographical survey, which gave us enough information to conduct our assessment without needing to visit site, therefore reducing costs. Waterco’s desk based review of existing flood risk data (including a Sitecheck Flood Report, The West Cheshire Strategic Flood Risk Assessment and historic, local and national press coverage) found the primary source of flooding to the site to be fluvial from the River Weaver. The Environment Agency’s predicted flood levels were compared to the site levels in order to inform the design process that by relocating the proposed classroom, showers and changing rooms onto the higher end of the site they would be unaffected during a 1 in 100 year flood event. This saved our client expensive design solutions of raising floor levels or introducing flood resilient doors and fittings. The proposed development would lead to an increase in impermeable area causing an increase in peak rate and volume of surface water run-off. We recommended a variety of the most appropriate SUDS solutions subject to infiltration tests being carried out at the next stage of design.
*The PPS25 guidance changed to NPPF (National Planning Policy Framework) in March 2012. Waterco now produces reports compliant with NPPF.
Waterco recommended a Flood Response Plan that would identify an evacuation route to higher ground, which would be used in the event of people being on site during a flood event. The Planning Application was granted without any comments or amendments to the Flood Risk Assessment.
01824 702220, www.waterco.co.uk, enquiries@waterco.co.uk Waterco Ltd. Eden Court, Lon Parcwr Business Park, Ruthin, Denbighshire, LL15 1NJ
Case Study Flood Risk Assessment Flood Zone 1 Greater than 1 Hectare
Alexandra Dock, Liverpool Ÿ Industrial Development Ÿ Surface water run-off appraisal Ÿ Discussions with Environment Agency and United Utilities
Scheme Full Planning Permission was sought for a proposed industrial development. This would include a gasification facility to process waste material and a generation facility to produce electricity. The proposed development was classified as ‘less vulnerable’ in accordance with PPS25.
Objectives The proposed development was shown on the Environment Agency Flood Map as Flood Zone 1. This means the change of flooding each year from rivers or the sea is 0.1% (1 in 1000) or less. As the site area was greater than 1 hectare a Flood Risk Assessment in accordance with PPS25 was required to investigate and advise on the most appropriate Surface Water Drainage solutions and ensure the development did not affect flood risk elsewhere. All possible sources of flooding were also considered.
Outcomes and Solutions The existing surface water arrangements were investigated. The existing site was entirely impermeable and connected to a nearby public sewer via a Hydrobrake. It was shown that the new development would not increase surface water run-off rates or volumes, as the impermeable area would not increase. Surface water run-off calculations were carried out to asses the effect of Climate Change. It was proposed to divert surface water from the new development directly into the Liverpool Dock. It was discovered that Bootle has problems with sewer flooding. Diverting surface water to the dock, meant there would be a reduction in surface water discharged to the combined sewer, helping to reduce possible sewer flooding elsewhere. It also released extra capacity for foul flows. It was confirmed with the Mersey Docks and Harbour Company that surface water could be discharged into Liverpool’s Dock system. It was also shown that this would not increase flood risk as it would eventually drain to the estuary, therefore no attenuation was required. Due to the sites proximity to the tidal River Mersey and the effects of climate change the EA originally required a 600mm freeboard for the proposed building. Waterco successfully showed that a 300mm freeboard including flood resilience measures would be sufficient.
01824 702220, www.waterco.co.uk, enquiries@waterco.co.uk Waterco Ltd. Eden Court, Lon Parcwr Business Park, Ruthin, Denbighshire, LL15 1NJ
Case Study Breach Assessment Assessment of flood risk posed to site from possible breach of coastal defences
Immingham, South Humberside Ÿ Ÿ Ÿ Ÿ Ÿ Ÿ
Modelling breach of coastal defence Extreme Flood Outlines Hazard Mapping Advising on Solutions Liaison with the EA Hydraulic Modelling Report
Scheme Waterco were instructed to produce a series of breach assessment models for a proposed commercial scheme to the north of Immingham Dock, South Humberside. By simulating a possible breach in the local Humber Estuary coastal defences the hazards and risks posed to the site could be quantified.
Strategy After an initial review of the scheme, the local Environment Agency Office was contacted to discuss any specific modelling requirements and the specific hydrodynamic parameters to be applied. We have found that early involvement with the EA and other outside agencies proved invaluable and enabled the acceleration of scheme progress, ultimately leading to client savings. Once these parameters had been agreed construction of the 2D hydrodynamic model could start. A Digital Elevation Model (DEM) of the area was created using high resolution LiDAR data. Detailed level information of any important local features e.g. the coastal defences were added for refinement. The 2D models, created in MIKE 21 from DHI, used this DEM to simulate the overland flow resulting from a breach in the defences under a series of predicted tidal cycles. The effects of climate change were also taken into account.
Outcomes and Solutions The extracted results from the completed simulations gave detailed information on the predicted flood levels, depths, rate of rise and speed of onset. This information was then used in conjunction with DEFRA guidance note ‘Flood Risks to People’ to produce a hazard map to further evaluate the impact of such a failure on the proposed developments and the surroundings. In addition to producing a full modelling report, we used the powerful results visualisation tools of DHI to produce a series of animations and flood outline maps. Provided on DVD, these results presentations are an excellent way of illustrating the flood risk and a foundation on which mitigation measures can be appraised. For more information on our hydraulic modelling capabilities please visit our web site or contact us using the details below.
01824 702220, www.waterco.co.uk, enquiries@waterco.co.uk Waterco Ltd. Eden Court, Lon Parcwr Business Park, Ruthin, Denbighshire, LL15 1NJ
Case Study Coastal Breach Assessment Assessment of flood risk posed to site from possible breach of natural coastal defences
Warren Drive, Prestatyn Ÿ Ÿ Ÿ Ÿ Ÿ Ÿ
Advice on Flood Risk at the Masterplanning Stage Modelling Breach of Natural Coastal Defences Liaison with the EA Hydraulic Modelling Report Extreme Flood Outlines & Depths Hazard Mapping
Strategy After an initial review of the scheme, the local Environment Agency Office was contacted to discuss specific modelling requirements and the hydrodynamic parameters to be applied. Early involvement with the EA and other outside agencies proves invaluable and enables the scheme progress to be accelerated, ultimately leading to client savings. Flood risk to a site can be a ‘show-stopper’ and should be understood and accounted for at the Masterplanning stage of the design process. Flood risk to a site can change the development layout, design and type of use. Once the modelling parameters had been agreed, construction of the hydrodynamic model could start. A Digital Elevation Model (DEM) of the area was created using high resolution LiDAR data. Denbighshire County Council provided dune survey data & sea wall crest levels. Detailed level information, along with a topographical survey of the existing site was added to refine the model. The hydrodynamic models, created in MIKE 21 from DHI, used this DEM to simulate the overland flow, resulting from a breach in the defences, under a series of predicted tidal cycles. Overtopping of a fluvial sluice gate, which controls discharge into the Irish Sea, was also simulated. The effects of climate change were taken into account.
Scheme Acting as a sub-consultant Waterco was instructed to produce a series of breach assessment models to determine flood risk posed from the Irish Sea to a proposed development site in the coastal town of Prestatyn, North Wales. Prestatyn is protected by both formal (sea wall) & informal (dune system) coastal defences. A breach in the dune system was more probable; this was to be simulated and the hazards and risks posed to the site quantified.
Outcomes and Solutions Understanding flood risk at the outset can enable simple alterations to a development design to limit potential flood damage and mitigation costs. The results extracted from the completed simulations gave detailed information on the predicted flood levels, depths, rate of rise and speed of onset. This enabled design of the development to be focused in the areas least at risk of flooding. This information was then used in conjunction with DEFRA guidance note ‘Flood Risks to People’ to produce a hazard map to further evaluate the impact of a breach in the defences on the proposed development and the surroundings. This provides understanding on the safest access/egress routes in a flood event. In addition to producing a full hydraulic modelling report, we used the visualisation tools of DHI to produce a series of animations and flood outline maps. Provided on DVD, these presentations are an excellent way of illustrating the flood risk and a foundation on which mitigation measures can be appraised. Examples of these animations can be found on our YouTube Channel at: www.youtube.co.uk/watercoltd
01824 702220, www.waterco.co.uk, enquiries@waterco.co.uk Waterco Ltd. Eden Court, Lon Parcwr Business Park, Ruthin, Denbighshire, LL15 1NJ
Case Study Hydraulic Modelling Assessment of flood risk posed to site from overtopping of river defences during extreme events
Beddgelert, Gwynedd Ÿ Integrated 1D and 2D hydraulic model Ÿ Flow assessment of rivers (FEH Statistical) Ÿ Extreme Flood Outlines, Depths & Velocities Ÿ Flow route determination Ÿ Hazard Mapping Ÿ Flood Mitigation Measures
Scheme Waterco was instructed to prepare a Flood Consequences Assessment Report, including hydraulic river modelling, in support of a planning application for the proposed conversion of an existing National Trust shop into a residential holiday home. The site lies in the heart of the small town of Beddgelert, Gwynedd located at the confluence of two rivers; the Afon Glaslyn and Afon Colwyn. The potential flood hazard was fully investigated and a range of flood mitigation measures proposed.
Strategy In order to determine the predicted flood levels at the site, catchment analysis and hydraulic flood modelling were required in accordance with the EA’s guidelines. A Hydrology Assessment was completed for each river with predicted peak flows for 1% a.e.p. and 0.1% a.e.p events being calculated using the FEH Statistical method (WINFAP-FEH 3). Climate change was also taken into account. Having established the predicted flows and agreed the modelling parameters with the local EA office, a 1D river network model was constructed in MIKE 11 to simulate both the rivers and their confluence. All structures on each river were also included.
Outcomes and Solutions The simulation results were subject to detailed analysis with detailed predicted flood depth, velocities and flow routes being determined. This information was then used in conjunction with DEFRA guidance note ‘Flood Risks to People’ to produce a hazard map to further evaluate the impact of such a failure on the proposed development and the surroundings. Having quantified the potential flood risk at the site, Waterco completed a Flood Survey Assessment detailing the possible mitigation measures that could be incorporated into the development to allow it to proceed. For more information on our hydraulic modelling capabilities please visit our web site or contact us using the details below.
This 1D river model was then linked to a 2D spatial model developed from LiDAR data and site specific level data.
01824 702220, www.waterco.co.uk, enquiries@waterco.co.uk Waterco Ltd. Eden Court, Lon Parcwr Business Park, Ruthin, Denbighshire, LL15 1NJ
Case Study Hydraulic Modelling Flood Zone Reclassification and Hazard Mapping
Cresswell, Staffordshire Ÿ Integrated 1D and 2D hydraulic model Ÿ Flow assessment of rivers (FEH Statistical) Ÿ Extreme Flood Outlines, Depths & Velocities Ÿ Flow route determination Ÿ Hazard Mapping Ÿ Flood Zone Reclassification Ÿ Flood Mitigation Measures
Strategy The area was remodelled using an integrated 1D/2D hydraulic model developed using MIKEFLOOD, DHI’s advanced hydraulic modelling software application. A 1D river network model of the River Cresswell and associated tributary was linked with a detailed spatial model of the floodplain, developed from high resolution LiDAR data and site specific level data. Using a relatively fine grid resolution (2m²) for the digital elevation model (DEM), a much improved representation of the floodplain was possible. Using calculated and agreed fluvial event flows (FEH Statistical and ReFH) it was possible to more accurately simulate the possible flood events at the site and so better understand the possible extent of flooding. Both the 1% a.e.p. and 0.1% a.e.p events were simulated with allowances for climate change being included as appropriate.
Scheme Waterco was instructed to carry out detailed hydraulic modelling of the River Blithe near Cresswell. The results were used as supporting evidence in the Flood Risk Assessment being prepared for a planning application at the site for a proposed biomass power plant. The client was SKM-Enviros. The current EA flood map for the area shows the site to be at widespread flood risk during extreme fluvial events. Following a review of the existing modelled data at the location it was understood that a more accurate assessment of the flood risk posed to the site could be achieved through the use of more accurate data and techniques. In addition to removing this particular objection, a more accurate representation of the floodplain would help inform final design layouts and any required flood mitigation measures.
Outcomes and Solutions The simulation results were subject to detailed analysis with predicted flood depth, velocities and flow routes being determined. This information was then used in conjunction with DEFRA guidance note ‘Flood Risks to People’ to produce a hazard map to further evaluate the impact of such flooding on the proposed development and the surroundings. It was shown that the current EA flood map for the area is overly conservative and that much of the site is actually shown to be flood free during 0.1% a.e.p. fluvial event. Our model was accepted by the EA and successfully demonstrated that the flood zone should be reclassified to reflect the true flood hazard posed to the site. The results will be used by the EA to update the EA flood map for the area. For more information on our hydraulic modelling capabilities please visit our web site or contact us using the details below.
01824 702220, www.waterco.co.uk, enquiries@waterco.co.uk Waterco Ltd. Eden Court, Lon Parcwr Business Park, Ruthin, Denbighshire, LL15 1NJ
Case Study Hydraulic Modelling Detailed hydraulic model enabling reclassification of flood zone
Hailes, Gloucestershire Ÿ Integrated 1D and 2D hydraulic model Ÿ Flow assessment of river (FEH Statistical) Ÿ Flood Zone Reclassification Ÿ Extreme Flood Outlines, Depths & Velocities Ÿ Flow route determination Ÿ Hazard Mapping
Scheme Waterco was instructed to undertake a Flood Risk Assessment, including hydraulic river modelling, in support of a planning application for the proposed development near Hailes, Gloucestershire. The site is currently shown on the Environment Agency (EA) flood map to be at flood risk during a 1 in 200 year event. It was hoped that following detailed modelling of the local features, the flood zone would be reclassified and the development objection removed.
Strategy The existing hydraulic modelling is based on a relatively coarse grid resolution and may not account for local topographical features and structures. A detailed 1D river network model was integrated with a 2D spatial digital elevation model (DEM) to more accurately simulate possible flooding at the site and in the local area. As agreed with the local EA office, the predicted peak flows and hydrographs were calculated using FEH Rainfall Run-off Method (ReFH spreadsheet). Climate change was also taken into account. The 1D river network, prepared in MIKE 11, simulated the small watercourse running past the site in addition to a number of existing culverts and partial blockages.
Outcomes and Solutions All simulations demonstrated that the site was not at risk of flooding from the events considered. Predicted flood depths, velocities and flow routes were extracted and a hazard map produced. In addition to producing a full modelling report, we used the powerful results visualisation tools of DHI to produce a series of animations and flood outline maps. Provided on DVD, these results presentations are an excellent way of illustrating the flood risk. Initial indications suggest that this report will be accepted by the EA with the flood zone being reclassified to Zone 1. For more information on our hydraulic modelling capabilities please visit our web site or contact us using the details below.
This 1D river model was then linked to a 2D spatial model developed from LiDAR data and site specific level data. 1% a.e.p. and 0.1% a.e.p. events were considered.
01824 702220, www.waterco.co.uk, enquiries@waterco.co.uk Waterco Ltd. Eden Court, Lon Parcwr Business Park, Ruthin, Denbighshire, LL15 1NJ
Case Study Hydraulic Modelling Flood Consequences and Solution Assessment for extreme floods
Pontsticill Water Treatment Works Ÿ Flow assessment from impounding reservoir Ÿ Integrated 1D and 2D hydraulic model Ÿ Investigation of previous flood events Ÿ Fluvial and overland flooding Ÿ Flood extents, depths and velocities Ÿ Modelling of solution options Ÿ Flood protection measures
Scheme Waterco was instructed by Dŵr Cymru Welsh Water to refine the existing flood risk information to determine the areas of the site at risk from a 1% a.e.p. event including allowance for climate change. Our brief also included the proposal and assessment of options for protection against this risk. The scheme was extended to include the preparation of the design package to install all the elements of the selected solution.
Strategy A hydrology assessment was completed for the catchment and the impounding reservoir spillway. This used the revitalised FSR/FEH rainfall-runoff method and catchment descriptor information from the latest software. The attenuation effect of the reservoir on the peak inflows was calculated to create an outflow hydrograph for the river flows for the 2%, 1% and 1% with climate change events. A 1D river network model of the Taf Fechan river including weir and bridge structures was linked with a detailed 2D spatial model developed from LiDAR data and site specific level data. Overland flow was also modelled using the 2D spatial model. Detailed analysis of the results predicted flood depths, velocities and flow routes across the site. Solution options were also modelled. These included the erection of a flood wall, the removal of a bridge, removal of a weir and bypass of the weir. As well as estimating the cost, the design, construction and operation of each option were considered.
Outcomes and Solutions In addition to the Flood Consequences Assessment Report, hydrology assessment and modelling report, we provided a cost benefit assessment of the solution options. Our recommended solution was to install a new river channel bypass to the gauging weir for use during high flows, raise one bank and clear some vegetation to protect against fluvial flooding. Other measures to protect against overland flow included protecting building thresholds and enlarging the flow route draining the site. We arranged site surveys and completed the Planning and Flood Defence Consent applications, so the work could be completed as programmed. The completed scheme will provide passive flood protection and enhance the biodiversity of the river habitat. For more information please visit our web site or contact us using the details below.
01824 702220, www.waterco.co.uk, enquiries@waterco.co.uk Waterco Ltd. Eden Court, Lon Parcwr Business Park, Ruthin, Denbighshire, LL15 1NJ
Case Study Water Supply Design Complete Scheme Design & Project Management
Glascoed to Llannerch Pipeline Ÿ Detail Design Ÿ Tender package under NEC conditions of contract Ÿ Project Management Ÿ Replacement of 5km of existing pipeline Ÿ Phasing of the scheme to ensure a continued supply to the treatment works Ÿ Route evaluation Ÿ Installation and commissioning of the new pipeline.
Scheme The Water Treatment Works at Glascoed near St Asaph, North Wales supplies potable water to a significant part of North East Wales. The existing 500mm GRP main providing raw water to the works from three boreholes had, in recent years, suffered a large number of bursts causing supply problems and in some cases flooding of premises, including the local Welsh Assembly Government offices. Waterco were commissioned by UUOS on behalf of Dŵr Cymru Welsh Water to carry out the complete design of the scheme including valves and flow monitoring. In conjunction with UUOS, Waterco put together the tender package under NEC conditions of contract and managed the complete tender process through to procurement.
Strategy During the construction phase, which was funded under the Dŵr Cymru Welsh Water capital maintenance programme, Waterco were responsible for project management of the scheme to ensure programme deadlines were met and budgets not exceeded. Although the scheme involved replacement of 5km of existing pipeline the project was split into two sections. The central section of the existing pipe ran under a river and had not caused any problems, as such this section remained in situ and either side of this was replaced. This involved phasing of the scheme to ensure a continued supply to the treatment works whilst new valve complexes and flow meters were installed. Alternative construction techniques were investigated at the design stage to ensure strict budgets were adhered to and deadlines met. This also involved route evaluation to ensure minimal disruption and hence third party claims for compensation.
Outcomes and Solutions Due to Waterco operating a flexible working policy for its staff the contractor was able to take advantage of daylight hours and planned shutdowns by UUOS operational staff such that no disruption was caused to Dŵr Cymru Welsh Water customers during the contract. Throughout the design and construction stages Waterco were responsible for ensuring that all environmental agencies were consulted and relevant consents obtained for the likes of watercourse crossings and hedgerow removal. The scheme also involved substantial newt fencing as this area of North Wales is home to one of the country’s largest populations of Great Crested Newts. This scheme also fell within the requirements of CDM and as such Waterco were responsible for ensuring all designers risk assessments were carried out and held regular meetings with UUOS H&S representatives. Continued liaison with landowners and UUOS property services ensured smooth running of the project but key to the schemes success was regular progress meetings with both the contractor and the client to ensure any problems were quickly resolved. During the construction phase Waterco were involved in the installation and commissioning of the new pipeline which included a presence during the charging and pressure testing to witness the successful installation. Dŵr Cymru Welsh Water now have a secured supply of raw water to the treatment works and an improvement to the services they provide to their customers.
01824 702220, www.waterco.co.uk, enquiries@waterco.co.uk Waterco Ltd. Eden Court, Lon Parcwr Business Park, Ruthin, Denbighshire, LL15 1NJ
Case Study Asset Security Regulatory compliance and business planning
Dŵr Cymru Welsh Water Ÿ Meet responsibilities under SEMD The Security and Emergency Measures (Water and Sewerage Undertakers) Direction 1998 Ÿ Compliance with advice notes from the Centre for Protection of National Infrastructure and the Water UK Standard for Security Arrangements, endorsed by DEFRA and its Security Adviser Ÿ All water and wastewater assets Ÿ Planning of surveys to suit operational staff Ÿ Technical solution meetings Ÿ Regular progress reporting Ÿ Clear results summaries
Strategy In order to effectively plan and deliver security improvements during AMP5 and AMP6, selected samples of all water and wastewater asset types have been surveyed. Alternative options have been considered and the required security improvements have been specified. Complete records have been provided for each asset and summaries have been collated to apply to all assets. In parallel with this, data on the status and category of all assets have been obtained or verified for producing a comprehensive business plan. The knowledge and experience of operational staff has been incorporated in each of the schemes carried out over a period of 5 years. This has resulted in verified, reliable and auditable data to improve asset security across the business.
Schemes Waterco has provided support services to Dŵr Cymru Welsh Water on five separate schemes to improve security for the water supply and sewerage services that Dŵr Cymru Welsh Water supplies to over three million people living and working in Wales as well as some adjoining parts of England. These schemes involved: scoping and budgeting in preparation for AMP5 and AMP6; developing in-house guidance on the application of the standards; surveying, specifying improvements and providing estimates for delivery in AMP5; similar work in advance of AMP6 and categorisation of all the water and wastewater assets for planning AMP6 expenditure. Waterco’s team worked closely with a considerable number of the client’s operational staff, planning site visits and managing data on thousands of assets.
Outcomes and Solutions By focusing on the information and deadlines required by Dŵr Cymru Welsh Water, Waterco prioritised assets and worked with the client, to record security information on existing assets. Additional guidance was developed and applied by discussion of particular and alternative solutions to meet the required standards with the Resilience and Security Managers and with the framework suppliers of security products. Full asset records were provided including photographs, summary records, specifications and estimates. Waterco’s thorough auditable methods and results satisfy the requirements of a regulated utility and we have provided support for external audits. All the data was issued in agreed formats for the client to use to update its master records. Some programmes were accelerated to meet the client’s business requirements for regulatory price reviews in 2009 and 2014. Examples of added value include clarifying the client’s asset data and providing additional reports including one on different maintenance practices. Dŵr Cymru Welsh Water now has plans in place to ensure all of its national infrastructure is protected to industry standards, and its delivery programme is underway.
Other Asset Management Schemes By creating a template, Waterco has also provided Total Loss Contingency Plans for water companies to provide alternative water supplies to their customers in the event of a treatment works failure. Operating manuals have also been produced using the client’s format to document information collated from several area of the business.
01824 702220, www.waterco.co.uk, enquiries@waterco.co.uk Waterco Ltd. Eden Court, Lon Parcwr Business Park, Ruthin, Denbighshire, LL15 1NJ
Tel: 01824 702220 www.waterco.co.uk | enquiries@waterco.co.uk
Water
Hydrology and Water Quality Modelling, Security, Asset and Strategic Planning, Pipelines and Distribution Systems (including self lay)
Drainage
Pre-Planning Assessment, SUDS, Groundwater Modelling, Sewerage and Sewage Treatment
Flood
Risk and Consequences Assessment, Hydraulic Modelling, Catchment Management, Flood Risk Management, Flood Hazard Maps and Response Plans, Coastal and Breach Assessments
Waterco Ltd. Eden Court, Lon Parcwr Business Park, Ruthin, Denbighshire, LL15 1NJ