Hydraulic Modelling and Risk Mapping Statement of Requirements and Outline Brief Template Technical Group www.sfrm.co.uk

1. Introduction Project title Walverden Water Strategic Flood Risk Mapping Study Project reference tbc Project stage Inception and main stage Environment Agency Region North West Environment Agency Area North Environment Agency Project Manager Louise Cramp Environment Agency Project Executive Sally Daniels Project Partner(s) n/a Address: Lutra House Dodd Way (Off Seedlee Road), Walton Summit, Contact details for Environment Agency Bamber Bridge, Project Manager Preston, PR58BX Telephone: 01772 714010 Email: [email protected]

2. Health & Safety and environmental considerations The Environment Agency has a statutory duty to ensure that the employees and consultants it employs are competent in the tasks they perform with regard to health, safety, wellbeing and environmental responsibilities. Compliance with Health and Safety legislation was addressed when the SFRM2 framework was tendered for and general requirements for Health and Safety (such as working hours, site visit risk assessments, etc) are covered by this.

3. Description of requirements Objectives A flood risk mapping study is to be undertaken on Walverden Water a tributary of Pendle Water in the River Ribble catchment. The Walverden Water Flood Alleviation Scheme works are nearing completion.

A defended hydraulic model for the Walverden Water Flood Alleviation Scheme exists and was last updated in 2010. Due to changes to the river channel and structures during the scheme works and inconsistent topographic survey data, we require a defended and undefended model to be produced. The existing defended model will be made available for the purposes of comparison. Complex overland flow routes are present in the study area but current flood zones are derived from National Generalised modelling. Flood Zones would need updating and an ABD produced.

Study area Maps showing the geographic location of the study area are included in Appendix A.

Catchment Main Watercourse Watercourse Reach Downstream Upstream Length No. Reference Name NGR (m) Catchment Number NGR

10 Ribble WALV Walverden 1 385435, 387005, 3.5 Water 438622 436680

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Table 1 – Watercourse to be included in study. Deliverables The draft and final reports of the project must follow the SFRM performance scope available from www.sfrm.co.uk.

A detailed list of model outputs required is provided in Appendix B.

- Watercourses to be considered are those listed in Table 1 and shown in the enclosed .pdf;

- Build a defended and undefended hydraulic model for production of NFCDD deliverables;

- Update existing defended model with as built defence information and new topographic survey data;

- A Property Threshold Level survey, (with the prior consent of the Agency to a specification agreed with the Project Manager);

- Identify and map any areas benefiting from flood defences;

- Data to be provided in NFCDD (National Flood & Coastal Defence Database) compatible format;

- If the Inception Report (which should include chapters 1-4 of the main report) identifies the need for 2D modelling, the Main Phase must provide detailed depths, velocity and height grids for the study reach;

- Interim hydrology chapter in accordance with the latest EA procedures (EA Flood Estimation Guidelines, currently 06/11/09 but now being updated) and including an FEH pro-forma. This should be provided at an interim stage for EA review, with a final version included as part of chapter 5 in the final report. The most recent FEH software and hydrometric data (including Hiflows) must be used in the above procedures;

- Model and map the return periods listed in Appendix B;

- Outlines for all return periods to be delivered digitally (Mapinfo and ArcGIS format). (Level 1 and 2a mapping for example, are not required). Where 2d modelling has been undertaken, the depth, velocity and height grids will be provided;

- Draft Final Report - in accordance with Model Report Performance Scope (apart from the specified number of pages) and detailed enough for other staff to reproduce/re-use the results in the future. This will contain the finalised hydrology. It will fully detail the modelling approach used, details of key structures/issues, verification/calibration details, description of method of mapping, model handover guide including model schematics, key assumptions and limitations associated with the study, tables of results with related maps. These tables will comprise node labels, max stage and flow at each return period and standard of protection of existing banks/defences at each node point;

- Final Report;

- The sensitivity analyses will be agreed with the EA PM at a later date and included in the report. At this stage, assume; channel roughness +/- 20% Manning’s n, floodplain all at 0.1 n, downstream boundary, i.e. 4no scenarios;

- NFCDD data – correct, spatially clean, i.e. removal of bow-ties, double nodes, generalised to 1 metre etc;

- Monthly Progress Reports;

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- GIS layer showing locations of formal defences and de-facto defences identified in the Study Area. Any areas benefiting must benefit from a defence(s). This needs to be identified;

- Estimates of blockage sensitivity of key structures - selection methodology to be confirmed with EA. Sensitivity runs at 3 return periods (1 in 10, 1 in 50 and 1 in 100). Produce a standalone report for the blockage analysis (an example report is available on request).

Activities Description of activities expected from the consultant during the project:

ƒ project management; ƒ agree proposal (which should include chapters 1-4 of the main report); ƒ Monthly reports, verbal contact at least every two weeks; ƒ full walkover of the study area; ƒ procurement of new survey information will be managed by the Environment Agency; ƒ review and validation of existing topographic survey to ensure data is appropriate and fit for purpose. Desk top comparison of LiDAR data with topographic survey; ƒ preparation of suitable hydrology inputs for hydraulic model; ƒ agree hydrology before starting modelling; ƒ Rating review using existing hydraulic model; ƒ construction of appropriate hydraulic model; ƒ desktop study of historic flooding information; ƒ appropriate consultation with Environment Agency staff and partners; ƒ agreement of a sensible and consistent naming convention for model nodes; ƒ calibration of hydrological and hydraulic models and analysis of data against available information; ƒ sensitivity analyses and discussion; ƒ generation of draft flood outlines in digital format; ƒ production of draft report; ƒ quality assurance of all deliverables; ƒ assessment of supplier performance measures (SPMs); ƒ allow for review of draft report, hydraulic model and deliverables by Environment Agency; ƒ production of final report; ƒ production of model outputs defined above and in Appendix B; ƒ formal presentation of final outputs to client audience; ƒ post project appraisal.

4. Data Data available

• Relevant OS 1:10,000; 1:25,000, 1:50,000 and 1:250,000 digital mapping; • Formal defence data if applicable, (from NFCDD); • Relevant OS Mastermap data; • 1m resolution LiDAR data is available for the study area; • Hydrometric data; • Hiflows UK http://www.environment-agency.gov.uk/hiflowsuk/; • Existing models and studies - The Walverden Water Flood Alleviation Scheme study which covers Walverden Water was completed in 2005, the model was then updated in 2010. Work carried out post 2010 update has made significant changes to some sections of the hydraulic model; in some instances the 2005 hydraulic model more accurately represents the river channel and structures. Both the model and report are available; Created by EA task group Page 3 of 9 Last updated 25‐May‐11 FINAL v1.1 Hydraulic Modelling and Risk Mapping Statement of Requirements and Outline Brief Template Technical Group www.sfrm.co.uk

• Existing models and studies - A hydraulic model for Pendle Water was completed in 2010 as part of the Burnley, Nelson & Colne Strategy, Walverden Water has been modelled as an inflow point into Pendle Water but the hydrology for the Walverden Water catchment was produced utilising Winfap v2; • Guidance for NFCDD deliverables; • Historical flooding information; • Topographic survey – A topographic survey of Walverden Water was carried out in 2003, this will be updated in 2011 post completion of the flood alleviation scheme. Data management plan The Environment Agency project manager should produce a data management plan for this study to scope the data needs for the project, the resources required for data acquisition, and cost savings which could be made by cooperating with other teams or partners on projects. The current national Environment Agency template should be used (available from operational instruction 183_05 which can be provided by the Environment Agency project manager) and supplemented by additional local requirements if necessary.

Intellectual property

There are clauses in the Contract Data Template (Option X9 and Option Clause Z4) related to IPR which help us ensure we manage Intellectual Property properly.

Data security ƒ Password protect electronic submissions. This needn’t apply to general correspondence and monthly reports.

Licensing Any data supplied to the consultant as part of this study will be done so in accordance with Environment Agency policy, and appropriate data licences. Any other data requested by the consultant will be provided and licensed for the duration of the study. Metadata Any new data or information that is created as part of a commission must be submitted to the Environment Agency with associated metadata.

5. Project management Outline budget

Outline programme ƒ Anticipate start date as 23rd May 2011 ƒ Inception stage complete by end of 27th June 2011 ƒ Hydrology complete by end of 15th August 2011 ƒ Complete by 31st December 2011 ƒ Allow 10 working days each for client reviews of Inception; draft Report(s), draft models, final draft deliverable. Pricing Option - NEC3 Professional Services Contract (PSC) Option A: Priced contract with activity schedule

Contract strategy ƒ allocation approach is mini-competition ƒ quality: price basis - 50:50 quality : price

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ƒ Consultants being approached are Mott MacDonald and Royal Haskoning. Tender return information ƒ Return to EA Project Manager at above address, digital or hard copy formats. Password protect electronic submissions ƒ Return of proposal by 17:00 Tuesday 11th May 2011. Late submissions will be returned and not considered External contributions None at present.

6. Consultant’s response The consultant must provide a technical / quality / price proposal (including programme / costs / risks) of a maximum of 3 sides of A4 (Mini-competition / Direct Award) or [insert number] pages (Full competition) + price schedule + CVs (no other appendices should be included).

The proposal should consist of the following information: Key project personnel Describe the key people to be used in the project and their roles. ƒ Organisation and roles To include organisation and governance of the project team and locations / logistics. ƒ Technical experience, qualifications and experience To include qualifications, relevant experience, technical quality and communications (reporting and consultation with the Environment Agency and partners). The consultant should provide CVs of key project staff including the Project Manager as an appendix to their proposal and should not exceed 2 sides of A4 paper per person / CV. Programme, risks, resources and contingency Refer to ‘Appendix 13: Contract Options and Risk – keeping it simple’ (available from www.sfrm.co.uk) for guidance. Method and approach ƒ Demonstrate an understanding of the aims and objectives of the study; ƒ Evaluate most appropriate methods and techniques to achieve desired outcomes; ƒ Identify aspects considered to be of key importance to the study and how any challenges might be addressed; ƒ Make an initial assessment of data available and identify any high level data quality or availability issues and how these might be addressed; ƒ Indicate how hydrology will be assessed (flood estimation, rating curves, etc); ƒ Make an initial review and discussion of the proposed model and how a risk-based approach will be applied to ensure cost savings; ƒ Include brief resume of similar projects where the consultant has delivered successfully; ƒ Consider appropriate quality assurance procedures to test and document the product’s suitability for its intended purpose. Innovation and value added ƒ Demonstrate any added value and/or innovative techniques provided within the project to reduce costs or increase efficiency. Additional services at additional cost to the project do not provide added value.

7. Evaluation of consultant proposal Assessment criteria The Environment Agency Project Manager and Procurement Officer will evaluate the

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consultants’ proposals. The scores will be weighted in the following way:

Quality 50% comprising: 1) Key Project Personnel 2) Programme, risks, resources and contingency 3) Method and approach 4) Innovation and value added

Price 50% comprising: The total priced contract (Option A) for carrying out the services in this assignment including the estimate of consultant owned risk. Survey costs to be included and assessed within contract value. No

8. Attachments Attachments ƒ Appendix A – Map showing the Main Rivers within the study area; ƒ Appendix B – Detailed specification of required outputs;

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Appendix A: Maps showing the study area

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Appendix B: Detailed specification of required outputs from project Format Electronic format only Version control All deliverables will be subjected to a suitable form of version control. Any revisions to documents or output should be accompanied by suitable incremental change in reference number. Model nodes These are provided with the NFCDD deliverable. These must be georeferenced and spatially correct. Water level and flood extents / outlines • The study must generate flows, water levels and flood extents / outlines for the following annual probabilities: Fluvial annual exceedance probabilities (return periods) to be mapped are 20% (5), 10% (10), 5% (20), 4% (25), 2% (50), 1.33% (75), 1% (100), 100 + 20% increase in flows to allow for climate change, 0.5% (200), and 0.1% (1000). This is for undefended and defended scenarios where applicable;

These will be delivered in Mapinfo format with the NFCDD ModelledFloodOutline deliverable, but an ArcGIS version is also required. Depth, velocity and height These outputs should be provided for all annual probabilities and be supplied in ASCII grid format to allow import into ArcGIS. Hazard No hazard mapping is required. Model log Future use of model will require other staff to understand the model. The model should be supplied with appropriate reporting that explains modelling decisions and details methods, values and approaches applied. Comments for each node within the model should also be provided within the modelling software. Metadata The Environment Agency populates a metadata database called the Information Asset Register (IAR). It is a requirement that all information produced by modelling work is appropriately tagged with metadata. The Environment Agency project manager will supply an IAR spreadsheet (and any supplementary local metadata requirements if appropriate) where all relevant metadata can be recorded and handed over on project completion. NFCDD data More guidance will be supplied during the project. The outline requirements are: 1) ModelledFloodGroup 2) ModelledFloodOutline 3) Nodepoint 4) ModelledNodepointMeasurement 5) AreaBenefiting (if applicable). Flood warning areas and triggers / threshold levels First property to flood threshold level and time taken to reach this level. There may be further requirements from the Incident Management Team, as the project progresses and flood risk is better understood. Areas benefiting from defences (ABD) If applicable, Create ABDs for the flood map. ABDs are produced according to Policy Document 132_06 and Work Instruction 301_06. An ABD is an Area that benefits from a defence in a 1% (1 in 100) annual probability flood from rivers or a 0.5% (1 in 200) annual probability flood from the sea. Climate change Q100 flows + 20%. Created by EA task group Page 8 of 9 Last updated 25‐May‐11 FINAL v1.1 Hydraulic Modelling and Risk Mapping Statement of Requirements and Outline Brief Template Technical Group www.sfrm.co.uk

Animations / visualisations Not required. Breach and blockage Estimates of blockage sensitivity of key structures - selection methodology to be confirmed with EA. Sensitivity runs at 3 return periods. Produce a standalone report for the blockage analysis, produce GIS datasets of outlines (an example report will be made available during the Project. Assume 10 key structures for the bid). Breach analysis not required. Surface water flooding Not required at this stage. Model datasets All datasets are required so we can reproduce and edit appropriately. Results and check files are also required. It is envisaged that the volume will be large – include a cost for provision of final deliverables on an external hard drive.

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