_Attachment 3_Desilting Report October 2012 - Hull City Council

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_Attachment 3_Desilting Report October 2012 - Hull City Council Powered By Docstoc
					 Report to the Environment and Transport Overview and                   Wards
 Scrutiny Commission
 2nd October 2012

                                 River Hull Desilting Funding Report

Report of Mark Jones, Head of Economic Development and Regeneration on
behalf of Pauline Davis, Corporate Director for Regeneration

1.   Purpose of the Report and Summary

     1.1.    This report is prepared in response to an enquiry raised by the
             Environment and Transport Overview and Scrutiny Commission to
             investigate the potential for desilting works on the River Hull to be funded
             via the emerging Community Infrastructure Levy (CiL).
     1.2.    The report concludes that there are marginal flood risk management
             benefits in carrying out desilting works on the River Hull, this was a key
             finding of the Environment Agency (EA) River Hull Flood Risk
             Management Strategy (2010) and due to this core DEFRA Grant in Aid
             funding cannot be attracted to deliver this option, the EA are currently
             appraising the preferred option of replacement and renewal of existing
             defences in the city.
     1.3.    CiL approaches are currently being developed but it is unlikely that
             revenues could be raised to deliver desilting programmes with potential
             costs of around £400k to dredge the River Hull in the city council area
             and repeated costs over time to ensure the continued benefits of
             desilting are enjoyed.
     1.4.    CiL will be an important approach to support other, more deliverable and
             effective, flood risk management initiatives such as aqua greens,
             defence works and SuDS, wider regeneration funding approaches are
             being considered at present to work alongside the DEFRA funding that
             will inevitably come to the city in the near future.

2.   Recommendations

     2.1.    It is recommended that the Commission notes and supports the findings
             of the report namely:
                   The limited nature of desilting to deliver flood risk benefits in the

Author: Steve Wragg, Flood Risk Planning Manager
Date: 26/05/2013                                                         Page 1 of 6
                     The disproportionate costs involved in desilting for flood risk
                   That CiL is unlikely to be able to cover the costs of desilting and
                      other more effective flood risk management uses of the funds
                      should be investigated
     2.2.    It is recommended that the Commission considers further work to scope
             out the key flood risk management approaches they want to be
             developed as CiL infrastructure priorities, although it may command a
             low priority it is recommended that desilting works are still included in
             this process.

     This is a non-key decision.

3.   Area Committee Impact

     3.1.      This report is not intended for submission to Area Committees.

4.   Background

     4.1      Hull City Council is a Lead Local Flood Authority (LLFA) and has permissive
              powers to manage flood risk issues on Ordinary Watercourses (none Main
              River), the Environment Agency have similar powers on Main River in the
              city, key examples being the River Hull, Humber, Beverley and Barmston
              Drain and Holderness Drain.
     4.2      More than 44,000 properties are at risk of flooding in the city – this is the
              worst case ‘without defences’ scenario. Interventions from all partners
              reduce the impact of flood risk to a vast majority of these properties but they
              are, of course, dependant on long term funding to ensure the benefits of this
              protection continue to have effect.
     4.3      The EA have two Flood Risk Management Strategies covering the city – the
              Humber and River Hull (including Beverley and Barmston and Holderness
              Drains). Both present strong business cases to maintain improve or develop
              new assets to ensure an appropriate standard of protection is in place
              across the city (including all requirements to manage the impacts of future
              climatic change) and long term funding is in place to appraise and deliver
              appropriate schemes. We are working closely with the EA on all aspects of
              these works.
     4.4      The Environment Agency River Hull Flood Risk Management Strategy
              (2010) concluded that the River Hull in the HCC area does not pose a
              ‘fluvial’ flood risk due to defences with a good standard of protection in the
              city, Tidal flows up the River Hull are managed by the Hull Tidal Surge
              Barrier and the defences behind this are currently high enough to contain
              any fluvial flows when the barrier is operated.
       4.5    Desilting has been shown to give little effect, the gradient of the river is set
              by an outcrop of rock at Stoneferry, this means that digging silt out upstream
              has the effect of creating a pond, rather than improving flow. The EA
              Strategy also showed major concerns over the adverse environmental
              impacts related with dredging.

Author: Steve Wragg, Flood Risk Planning Manager
Date: 26/05/2013                                                       Page 2 of 6
       4.6    In essence only a small reduction in flood levels could be achieved and the
              cost of desilting would be very high. The EA report indicated approximately
              £14.6 million would be required each time the whole River Hull system is
              dredged. This is not seen as an appropriate approach, however, defences
              along the River Hull will need to be raised in line with climate change uplifts
              and the EA are currently appraising these works.
       4.7    Our approach to CiL is currently being developed but it is in essence a way
              of charging new development to deliver a range of infrastructure outcomes
              that have been deemed as locally or strategically important. In recent
              workshops members of the Planning Committee showed support for the
              needs of flood risk management to be considered in CiL, this is most likely
              through the linkages with open space or public realm provisions. The
              workshops did conclude that there could be some conflicts between the
              desire to deliver local priorities raised by Area’s and the larger strategic
              projects that may be proposed. All area, relevant committees and scrutiny
              commissions will be briefed during the autumn and lists of priority projects
              will be drawn up.

5.   Issues for Consideration

     5.1.      Using the EA Strategy data desilting would cost approx £66,500 per
               km or £285,950 every time the Stoneferry to the Humber length was
               carried out and £455,525 for the full River Hull in the HCC boundary.
               All figures are very conservative and the additional costs of dredging in
               an urban environment and potential associated costs of undermining of
               existing structures have not been included.
     5.2       The timescales of repetition for this work would need to be assessed
               and costs would potentially decrease in subsequent operations but a
               large capital outlay would be required every 5 or perhaps 10 years to
               ensure the benefits continue to be realised.
     5.3.      The EA costs were estimated using data from the Norfolk Broads
               Authority assuming the same dredging methods could be used for the
               River Hull, though in reality initial outlay costs may be significant on the
               River Hull as the Broads Authority carry out dredging on a regular
               basis and costs are relatively low as a result.
     5.4       Detailed viability work is ongoing to indicate the appropriate charging
               rate that can be placed upon new developments and in turn the likely
               funding that will be generated from CiL, early considerations are that
               the margins from commercial developments would not be supportive of
               CiL and the charge is unlikely to be applied to these
               developments.Even with considerable incomes from CiL it is not likely
               that the capital costs required to commence an effective desilting
               programme will be supported and desilting works would command a
               very low priority. In addition to this the extremely marginal flood risk
               benefits that would be derived from desilting works in the city could
               suggest that it would not be an appropriate usage of such funding to
               manage flood risk.
     5.5.      DEFRA Flood Defence Grant in Aid funding is administered according
               to the recently adopted Partnership Funding approach where scheme
               economics are used to identify the funds that can be justified to
Author: Steve Wragg, Flood Risk Planning Manager
Date: 26/05/2013                                                         Page 3 of 6
               contribute to a scheme from central funds. All schemes can qualify for
               some funding, those that deliver the most ‘outcomes’ can receive
               100% funding. All schemes in Hull would feasibly fall into the latter
               scenario but the central ethos of the Partnership Funding approach is
               one of all schemes identifying possible beneficiaries or contributors
               and securing additional funding streams to help deliver a wider range
               of schemes from the central funding pot.
     5.6.      Flood alleviation projects funded via the Partnership Funding approach
               cannot consider future growth and expansion in their base economics,
               therefore, EA led schemes will not include regeneration economics in
               any of their proposals, similarly, any DEFRA funded schemes led by
               HCC will have the same constraints, but we can use dual funding
               options to progress wider benefits that cannot be justified from a single
               funders desired outcomes.
     5.7.      We will ensure that wider flood risk work is fully considered as part of
               CiL and the Flood Risk Planning Manager is currently working with
               Regeneration colleagues to explore the opportunities of using the
               likelihood of flood risk management funding in the city as a catalyst to
               lever in wider regeneration funds from a range of sources – LEP,
               Enterprise Zone, City Deal, ERDF etc.
     5.8.      The wider benefits of desilting the river for amenity / regeneration
               purposes may be appropriate to consider as regeneration led schemes
               develop, however, costs associated with such works and the long term
               commitment to maintain silt levels may preclude such approaches.
               Previous studies carried out by the council to investigate the creation
               of a barrage at the confluence with the estuary showed this to have
               extremely marginal economics but it would have wider regeneration
               benefits and obviously would manage the future siltation of the river
     5.9.      The council’s role as a navigation authority and the need to maintain a
               navigable channel on the river may require aspects of desilting work to
               be carried out, further work to investigate the requirements to satisfy
               this duty would be required.

6.   Options and Risk Assessment

     6.1.      The commission agree with the recommendations in section 2 based
               on the detailed hydraulic modelling and reporting of the EA River Hull
               Flood Risk Management Strategy.
     6.2       The commission disagree with the findings of the report evidenced
               from the EA Strategy and recommend that the council develop further
               investigations into desilting for Flood Risk Management, this will incur
               additional expense on the council.
     6.3       In addition to either of the two options above further investigations
               could be recommended by the commission to investigate the
               regenerative benefits of desilting and the role of desilting to deliver the
               duties of the council as a navigation authority, this will incur additional
               expense on the council.

Author: Steve Wragg, Flood Risk Planning Manager
Date: 26/05/2013                                                         Page 4 of 6
7.   Consultation

     7.1.      No further consultation has been held at this stage as the report is in
               response to a direct question from the commission, further consultation
               will be developed in accordance with the commissions conclusions.

8.   Conclusions

     8.1.      The report has shown desilting for flood risk management purposes
               alone to be ineffective and prohibitively costly, other approaches are
               being taken by all partners to reduce the impacts of flooding from the
               River Hull System.
     8.2       CiL is unlikely to raise the revenues required to deliver an effective
               desilting programme and any desilting works are likely to have a low
               priority in the emerging infrastructure priority list.
     8.3       Further work is recommended to identify potential flood risk
               management approaches that would be supported by CiL.

 Mark Jones, Head of Economic Development and Regeneration on behalf of Corporate
                            Director for Regeneration

Contact Officer :     Steve Wragg, Flood Risk Planning Manager, Telephone No. : 612129

Officer Interests:    None

Background Documents: - None

Author: Steve Wragg, Flood Risk Planning Manager
Date: 26/05/2013                                                       Page 5 of 6
                                             Implications Matrix

                                  If there are no implications please state

I have informed and sought advice from HR, Legal,           No
Finance, Overview and Scrutiny and the Climate
Change Advisor and any other key stakeholders i.e.
Portfolio Holder, Area Committee etc prior to
submitting this report for official comments
Is this report proposing an amendment to the budget         No
or policy framework?

I have value for money considerations been accounted        Yes
for within the report

I have had the report been approved by the relevant         Yes
Corporate Strategy Team/Head of Service

I have included any procurement/commercial                  Yes
issues/implications within the report

I have liaised with Communications and Marketing on         No
any communications issues

I have completed and Equalities Impact Assessment           No implications
and the outcomes are included within the report

I have included any equalities and diversity                No implications
implications within the report

I have included any community safety implications and       No implications
paid regard to Section 17 of the Crime and Disorder
Act within the report

I have liaised with the Climate Change Advisor and          Yes
any environmental and climate change
issues/sustainability implications are included within
the report
Any Health and Safety implications are included within      No implications at this stage
the report
Any human rights implications are included within the       No implications
How this report contributes to Council/Local Area           No
Agreement/Area priorities is included within the report

    Author: Steve Wragg, Flood Risk Planning Manager
    Date: 26/05/2013                                                          Page 6 of 6

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