Ayaz

January 1, 2012

School of Engineering Design and Technology

Skipton Case Study

Flood Alleviation Scheme

Ayaz Ahmed Soomro

UoB: 10039352

MSc Civil and Structural Engineering

Lecturer: Dr. Crina Oltean Dumbrava

Date: 20/April/2012

Lecturer: Dr. Crina Oltean DumbravaPage 1

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First Part of the Case Study

Scheme 1

Task1: Collection and analysis of the baseline information to define the flood alleviation scheme including the environmental, social and economic aspects, including but not limited to;

a. Utilities; Gas, electricity, foul water, potable & telecoms (Aijaz Ahmed Mahar)

b. Access and highways (Aijaz Ahmed Mahar)

c. Ground conditions (Ayaz Ahmed Soomro)

Task2: Consideration of feasible options for the flood alleviation scheme extent and location. Using a transparent appraisal methodology to evaluate 3 options and make clear reasoned arguments for a preferred layout. Consideration should be given, but not limited to;

a. Landscape: consideration should be given to the integration of the scheme within the historical town (Ayaz Ahmed Soomro shared with Aijaz Ahmed Mahar)

b. Sustainability – environmental, climate change, resources (Sukhy Singh)

c. Access; Construction and Maintenance (Ayaz Ahmed Soomro)

d. Nuisance; Noise and pollution etc. (Sukhy Singh)


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Second part of the Case Study

Task4: Technical development of flood protection option at the Medical Centre.

Regardless of the overall scheme preferred, local flood defences are anticipated to be required at the Medical Centre. For this specific location:

a. Prepare a general arrangement plan for this location, showing the proposed flood defences location (Ayaz Ahmed Soomro shared with Aijaz Ahmed Mahar)

b. Provide detailed showing the flood defences height, cross section and appearance (Ayaz Ahmed Soomro shared with Aijaz Ahmed Mahar)

c. Proposed construction access and working arrangements (Ayaz Ahmed Soomro shared with Aijaz Ahmed Mahar)

d. Maintenance management plan proposed for the flood defences (Ayaz Ahmed Soomro shared with Aijaz Ahmed Mahar)

e. Climate change retrofit solution (Ayaz Ahmed Soomro shared with Aijaz Ahmed Mahar)


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Table of ContentsFirst Part of the Case Study................................................................................................2

Scheme 1............................................................................................................................2

Task1: Collection and analysis of the baseline information to define the flood alleviation scheme including the environmental, social and economic aspects, including but not limited to;................2

a. Utilities; Gas, electricity, foul water, potable & telecoms (Aijaz Ahmed Mahar)...................2

b. Access and highways (Aijaz Ahmed Mahar)...........................................................................2

c. Ground conditions (Ayaz Ahmed Soomro).............................................................................2

Task2: Consideration of feasible options for the flood alleviation scheme extent and location. Using a transparent appraisal methodology to evaluate 3 options and make clear reasoned arguments for a preferred layout. Consideration should be given, but not limited to;.....................2

a. Landscape: consideration should be given to the integration of the scheme within the historical town (Ayaz Ahmed Soomro)..........................................................................................2

b. Sustainability – environmental, climate change, resources (Sukhy Singh).............................2

c. Access; Construction and Maintenance (Ayaz Ahmed Soomro)............................................2

d. Nuisance; Noise and pollution etc. (Sukhy Singh)..................................................................2

Second part of the Case Study............................................................................................3

Task4: Technical development of flood protection option at the Medical Centre............................3

Regardless of the overall scheme preferred, local flood defences are anticipated to be required at the Medical Centre. For this specific location:...........................................................................3

a. Prepare a general arrangement plan for this location, showing the proposed flood defences location (Ayaz Ahmed Soomro)......................................................................................3

b. Provide detailed showing the flood defences height, cross section and appearance (Ayaz Ahmed Soomro).............................................................................................................................3

c. Proposed construction access and working arrangements (Ayaz Ahmed Soomro)...............3

d. Maintenance management plan proposed for the flood defences (Ayaz Ahmed Soomro)...3

e. Climate change retrofit solution (Ayaz Ahmed Soomro)........................................................3

Chapter 1...........................................................................................................................7

1.0 Introduction.............................................................................................................7

1.1 General Outlook....................................................................................................................7

1.2 Skipton Town.........................................................................................................................7

1.2.1 Historical flooding in Skipton.........................................................................................8

Chapter 2.........................................................................................................................10


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2.0 Site Investigation...................................................................................................10

2.1 Utilities.................................................................................................................................11

2.2 Access and Highways...........................................................................................................12

2.3 Ground conditions...............................................................................................................13

2.4 Landscape............................................................................................................................16

2.5 Access (Construction and Maintenance)..............................................................................16

2.5.1 Site plan for Morrison supermarket Culvert:...............................................................17

2.5.2 Site plan of Medical Centre Embankment Walls..........................................................18

Chapter 3.........................................................................................................................19

3.0 Team Proposal 1....................................................................................................19

3.1 Identification of locations of weak structure:......................................................................19

3.1.1 What causes flooding at Morrison Supermarket.........................................................20

3.1.2 What causes flooding at Medical Centre.....................................................................22

3.1.3 What causes flooding at Eller Beck..............................................................................24

Chapter 4.........................................................................................................................29

4.0 Medical Centre.......................................................................................................29

4.1 Prepare a general arrangement plan for this location, showing the proposed flood defences location............................................................................................................................29

4.1.1 What causes flooding at Medical Centre.....................................................................29

4.2 Provide details showing the flood defences height, cross section and appearance............32

4.2.1 Raising Bridge...............................................................................................................32

4.2.2 Embankments walls:....................................................................................................32

4.2.3 Channel Relief Scheme.................................................................................................33

4.3 Proposed Construction Access and Working Arrangements................................................36

4.3.1 Construction Access.....................................................................................................36

4.3.2 Working Arrangements................................................................................................37

4.4 Maintenance management plan proposed for the flood defences.....................................38

4.5 Climate Change Retrofit Solution.........................................................................................39

Appendix: A......................................................................................................................41

Appendix: B......................................................................................................................47

Figure 1 Skipton Town Visited Site Map1............................................................................................10Figure 2 Skipton Town Visited Site Map 2...........................................................................................11Figure 3 Map shows Utilities location in Skipton Town.......................................................................12


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Figure 4 Location and access routes in Skipton Town .........................................................................13Figure 5 Locations of Bore Holes 1 - 3.................................................................................................14Figure 6 Location of Trial Pits 1, 3 – 5..................................................................................................14Figure 7 Shows Site planning for Morrison’s Supermarket..................................................................17Figure 8 Shows Site plan for medical centre embankment walls.........................................................18Figure 9 Shows Three key locations of Skipton where flooding always starts.....................................19Figure 10 Location of weak structure 1...............................................................................................20Figure 11 Location of weak structure 2...............................................................................................20Figure 12 Front view of Morrison Supermarket Culverts.....................................................................21Figure 13 Plan of Morrison’s Supermarket Culverts............................................................................22Figure 14 Location of Medical Centre..................................................................................................23Figure 15 Lack of Flooding Mechanism of River in Front of Medical Centre........................................23Figure 16 identification of weak structure at Medical Centre.............................................................24Figure 17 Shows Eller Beck River.........................................................................................................25Figure 18 Shows Floodwall with concrete cutoff.................................................................................26Figure 19 Example of floodwall and embankment close to river.........................................................27Figure 20 shows an example of Plastic Sheet Pilling Floodwall............................................................27Figure 21 Lack of Flood Stopping Mechanism for River at Medical Centre..........................................29Figure 22 Shows Uneven Ground Surface Level..................................................................................30Figure 23 Shows Bird Eye-View of River at Medical Centre.................................................................31Figure 24 Shows Areas Which Needed to be Strengthen Near Medical Centre..................................31Figure 25 Location of two car-parks near medical centre....................................................................32Figure 26 shows an example of Purposed Reinforcement wall for river near medical centre.............33Figure 27 Shows Example of Pre-stressed Concrete Cylinder Pipe Shapes..........................................34Figure 28 Plan of Pre-stressed Concrete Cylinder Pipe Scheme For Car-Park Next to Medical Centre 35Figure 29 Plan of Pre-stressed Concrete Cylinder Pipe Scheme For Car-Park opposite to Medical Centre..................................................................................................................................................35Figure 30 Plan of contruction access...................................................................................................36Figure 31 Shows an Example of Mixer Transferring Wet Concrete on Site..........................................37Figure 32 Shows Possible Potential Site Locations for Constructing (PCCP) Scheme...........................38Figure 33 Shows Example of installation of (PCCP) Scheme and also Type of Machine which can be use.......................................................................................................................................................38Figure 34 Shows Example of Green Houses Gases

Table 1 Historic flooding in Skipton........ ..............................................................................................8

Table 2 Brief Description of Bore holes and Trial Pits data..................................................................15Table 3 Shows overall material layer and their depths........................................................................16


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Chapter 1

1.0 Introduction

1.1 General OutlookFlooding is a natural and recurring event for a river or stream. Flooding is a result of heavy or continuous rainfall, the sea, and groundwater. River exceeding the absorptive capacity of soil and the flow capacity of rivers, streams, and coastal areas. This causes rivers to overflow its banks onto adjacent lands.

Flooding Risk:

Risk means a risk in respect of an occurrence assessed and expressed as a combination of the probability of the occurrence with its potential consequences

As a starting point a good way to think of this is as:-

‘Risk’ = probability of an occurrence x its potential consequence. Multiplication is likely to be a reasonable assumption in most circumstance but it may sometimes be important to recognise that a 1% annual probability event causing £10 million of damage may need to be managed differently from a 10% annual probability event causing £1 million of damage.

The definition states the potential harmful consequences to be considered in assessing flood risk. Flood risks are:

human health the social and economic welfare of individuals and communities infrastructure, and the environment (including cultural heritage)

Climate change over the next few decades is likely to mean milder wetter winters and hotter drier summers in the UK, while sea levels will continue to rise. These factors will lead to increased and new risks of flooding within the lifetime of planned developments.


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1.2 Skipton TownSkipton is small historic market town of North Yorkshire. This town is currently at risk of flooding from numerous watercourses rolling through the town. Small historic town of North Yorkshire (Skipton) has been suffering substantial degree of flooding during past few years. Essentially, 573 properties in Skipton are at risk of flooding from three watercourses: Eller Beck, Waller Hill Beck and Ings Beck.

The Leeds-Liverpool canal and its Springs Branch also pass over the centre of Skipton town. Eller Beck river flows through woodland just upstream of the town with high potential for entrapment of woody debris. As a result of these factors, flooding with a rapid onset is compounded by scour and culvert blockage problems. Flow velocities in the watercourses are very high and lead times of flood warning systems are very short (i.e. typically 2 hours), so there is a significant risk to life.

Skipton would suffer by environmental disorder as growing flood risk potential if left as the presence conditions of the structural weakness of flood defence. Therefore design team has concluded to take the better solutions from the applied proposals to keep Skipton safe from flood risk. All the selected proposals will take into consideration of sustainable and cost effective solution.

Figure 1 Skipton location in U.K. map


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1.2.1 Historical flooding in SkiptonThe Skipton town has experienced a significant degree of flooding, with major events occurring in 1908, 1979,1982,2000,2004 and 2007. Flow velocities in the watercourses are high. Eller Beck flows through woodland just upstream of the town with high potential for entrapment of woody debris. As a result of these factors, flooding with a rapid onset is compounded by scour and culver blockage problems. Table below shows brief history of flooding in Skipton town.

Event date Damages Comment

June 1908

Towpath wall collapsed between Eller Beck and Springs Branch.

Total property damage not known

Torrential storm on Rylestone Fell. 30mm rain in < 1 hour

June 1979

Widespread flooding on Waller Hill and Eller Becks

Estimated in excess of 50 properties flooded

Observed flood depths up to 1.2 m

As shown in Plate 1 below

66mm rain fell in 24 hours

Culverts blocked by debris caused overtopping(particularly Waller Hill Beck)

Significant overland flow as drains and channel flow routes blocked

June 1982

1 fatality

Significant property damage at Shortbank Road

Flow torrent down Shortbank Road, road surface ripped up

Intense summer rainstorm over high ground to south of Skipton

June 2000 25 properties flooded at Back bridge Street

Water backed up from Morrisons and Broughton Rd


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culverts

October 2000

Homes flooded at back Bridge St

Morrison’s supermarket and Focus DIY flooded

Ings Lane Industrial Estate flooded

Riverside wall collapsed at Back Bridge St

Table 1 Historic flooding in Skipton


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Chapter 2

2.0 Site InvestigationAt the start of the case study project, design team was given opportunities to visit Skipton town. Short trip to Skipton helped team to explore actual site location in very detailed.

During the trip design team was able to identify major problems which causes substantial amount of flood over the past few years in the Skipton town.

Identification of major problems during short trip to Skipton:

The potential problems that are causing flood in the Skipton;

Broken embankments walls along the River Eller Beck. Lack of depth/Height of embankment walls; i.e. especially at medical centre. Lack of blockage of culverts at upstream of River Eller Beck. Lack of capacity of water passage through Morrison Supermarket Culvert.

Please note that during the short trip to Skipton, team was visited only River Eller beck, Ings beck and Liver-pool Leeds Canal. Figures below shows site map and locations which were visited during short trip to Skipton town.

Figure2 Skipton Town Trip Site Map1


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Figure 3 Skipton Town Visited Site Map 2

Team was also given opportunity for collecting and analysis of the baseline information to define the flood alleviation scheme including the environmental, social and economic aspects, including but not limited to;

2.1 Ground conditionsThe ground conditions encountered across the site and Made Ground which are underlain by cohesive superficial deposits overlying mudstone. The details of the ground conditions are presented on the exploratory hole records.

Made Ground

The ground conditions encountered across the site generally comprise Tar macadam all exploratory holes encountered tar macadam 0.20 m thick. This was underlain by both cohesive and/or granular Made Ground. Granular material encountered as slightly sandy angular to sub angular, fine to medium gravel of limestone and sandstone was encountered in all exploratory holes to a maximum depth of 1.20m bgl(below ground level). Cohesive material was encountered only in between 0.5m and 0.8m bgl (below the granular material) and comprised soft sandy gravelly CLAY.

Superficial Deposits

Superficial deposits were encountered in all four boreholes to a maximum depth of 6.20m bgl. The material is predominantly cohesive, described as firm to very stiff slightly sandy, slightly gravelly to gravelly CLAY. The gravel is angular to sub angular, fine to medium of


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sandstone mudstone and quartz. Thirteen SPT tests carried out returned ‘N’ values of between 5 and 50, generally increasing with depth, and indicating a very soft to very stiff material.

Granular material was encountered from a minimum depth of 1.20m a maximum depth of 2.60m bgl This is described as a slightly sandy, slightly clayey angular to sub angular, fine to coarse GRAVEL of limestone, quartz and sandstone. SPT tests (2no.) which penetrated this material indicate a medium dense/dense material.

In the upper cohesive superficial deposits are suspected to be reworked material.

Four Atterberg limits tests carried out within the cohesive superficial deposits returned liquid limits of 22 to 35 % (average 33 %), plastic limits of 14 to 25 % (average 17 %) and plasticity indices of 9 to 24 % (average 15 %). This indicates a low to intermediate plasticity clay. Corresponding moisture contents ranged between 7.3 and 21 % (average 14 %).

Solid Deposits

Solid deposits, comprising very weak grey mudstone (partially weathered) were encountered at 6.20 and 4.90 m bgl respectively.

Two standard penetration tests (SPTs) carried out within the mudstone returned SPT ‘N’ values of >50.

Groundwater

Groundwater was encountered at 2.30m bgl during the site works. During monitoring, it was encountered between 1.44 m bgl and 3.40 m bgl

Observed Contamination

No visual or olfactory evidence of contamination was encountered during the investigation.

Exploratory Hole Made Ground Superficial Deposits Rockhead

THBH1 0 – 1.20m 1.20 – 3.80m 3.80 – 4.55 m

THTP1 0 – 0.20m 0.2 – 4.10m 4.10 – 4.20 m

THTP2 0 – 0.35m 0.35 - 3.90m 3.90 – 3.95 m

THTP3 0 – 2.0m 2.00 - 4.00m 4.00 – 4.10 m

THTP4 0 – 0.08m 0.08 – 4.10m 4.10 – 4.20 m

THWS2 0 – 1.00m 1.00 – 3.35m N/A

THWS3 0 – 0.3m 0.3 – 3.60m N/A


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Figure 4 Locations of Bore Holes 1 - 3


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Figure 5 Location of Trial Pits 1, 3 – 5


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Bore Hole and Trial Pits data relevant to Skipton fieldBore Hole Data

Bore Hole 1The bore is 19.5 meter deep and mostly consists of fine to coarse clayey organic sand, siltstone, mudstone, and sandstone with sub-angular to sub-rounded gravels. According to SPT N value the material underground is mostly medium dense. Ground water is found at the depth of 0.70m.

Bore Hole 2This hole has a depth of 9.20m. The top 2m layer is found as made ground. The material in this borehole is mostly medium dense and is consists of sandy gravels, cobbles, fine to coarse mudstone, sandstone, and siltstone is found in this borehole. Ground water is found at 3.2m and can rise up a further 1.2m.Bore Hole 3BH03 is 7.9m deep and the top 2.8m is very loose material. The underneath layers are made up of medium dense material.

Trial Pits Data

TP01This trial pit is just 1.9m deep and water strike at 1.2m. Angular and sub-angular gravels, cobble, boulder, sandstone and siltstone are found at this site.

TP03This trial pit is just 2.10m deep and no water is found in this test. Slightly sandy slightly gravely clay, occasionally cobbles, sandstone, quartz and mudstone. Angular and sub-angular gravels are found at this site.TP04This trial pit is just 2.20m deep and water strike at 2.0. Dark grey gravely medium to coarse sand. Gravel is angular and sub angular, fine and coarse including ash, ceramic glass, metal brick, sandstone, coal, mudstone and clinker.TP05At this site Clayey, slightly gravelly medium sand with sand stone, quartz and limestone strata is found. The trial pit is 3.10m deep. Water is found at 1.10m.The other scheme has no primary concern with ground conditions for raising embankments, however if needed the aforementioned data should be sufficient. There is more concern with digging under the Morrison’s car park; existing data from the old culvert design will be utilized. Dredging any area would require more information and extrapolation from existing (above) data would be useful.

Table 2 Brief Description of Bore holes and Trial Pits data


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During the trip to Skipton town, design team did not perform ground investigation tests. This was because of two main reasons; firstly due to the Health & Safety issues and also would cost lot of money i.e. heavy machineries involved to drill hole into ground. Secondly because of time limitations i.e. ground tests usually takes lot of time.

However because of above facts, therefore lecturer decided to provide good resources to students instead of asking them to perform ground investigation tests. Some resources were given to the team includes; lecturer notes, professional full data from Arup Company and library etc.

Since the huge data was available to team. Therefore design team took opportunity to use professional borehole data provided by Arup Company to identify materials types which exist to the ground. The following figures and tables are illustrating the information of site location, material layers and their depths. Further detailed data of bore hole and trial pits see in appendix B.

2.2 Landscape Since most of our proposals schemes are involved with either underground construction or refurbishment of current structure for the Medical Centre and Morrison Supermarket. Therefore these schemes do not have any major effect on the landscape of Skipton.

2.3 Access (Construction and Maintenance)For carrying out any project it is very necessary to plan access in advance. Term access may include in transporting and storing materials and heavy plant to the site.

Since the major construction work for scheme 1 is only involve improving of the Morrison Supermarket culvert and raising embankment wall of river at medical centre. To carry out construction work and to transport the material on the site therefore team has made site plan. This was to make sure that all the material are going to be transfer safe and secure without causing any distractions to anybody or any traffic.

Sometime transportation of Goods can cost approximately up 20-30% of the project if not carefully plan. It is also depend on the location of the site as well.

2.3.1 Site plan for Morrison supermarket Culvert:Figure below demonstrated the location of Morrison supermarket culvert, where construction process will be carried out. Constructing the additional part for the Morrison supermarket culvert, the construction processes will be carried out into two part i.e. site plan 1 (upper part of the culvert) and site plan 2 (lower part of the culvert).


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Figure 6 Shows Site planning for Morrison’s Supermarket

For upper part of the culvert:

Area of Site plan 1 will be used to store the materials and Plant. During the construction work of upper part of the culvert, access to the Morrison supermarket car park will be temporary closed. This is due to excavation of the ground of road near to roundabout. At the same time safety barrier will be used to keep the public out of the danger.

For lower part of the culvert:

Once the upper part of the culvert will be finished then construction process will be moved to the lower part of the culvert. This time safety barrier will be used around lower part of culvert to keep public out of danger. Site plan 2 will be used to store material and Plant, access for public will be open to buy groceries.


Site Plan 2

Site Plan 1

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2.3.2 Site plan of Medical Centre Embankment Walls

Figure 7 Shows Site plan for Medical centre embankment walls


Embankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical CentreEmbankment walls near Medical Centre

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Chapter 3

3.0 Team Proposal 1After surveying the site and identified major problems of floods in the historic Skipton town. The design team has proposed feasible solutions which would resolve flooding problem in town for at least 100 years.

Second proposal is mainly based on improvements/strengthens of the current structure which causes of flooding such as; refurbishing of current culverts and embankment walls. Throughout the short trip to Skipton, team carried out detailed investigation and identified locations of weak structure along River Eller Beck, Leeds & Liverpool Canal and Ings Beck. Figure below shows the three main areas which needed to be improve/strength.

Figure 8 Shows Three key locations of Skipton where flooding always occurring

3.1 Identification of locations of weak structure:The locations of weak structure which team felt need to be improving are; Culvert at Morrison Supermarket, raising the bridge at Medical Centre and some cleaning of rivers bed. Figures below illustrate two primary locations which needed to be improved.


Eller Beck River

Morrison’s supermarket

Medical Centre

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Figure 9 Location of weak structure 1

Figure 10 Location of weak structure 2

3.1.1 What causes flooding at Morrison SupermarketFlood occurs at Morrison supermarket when water comes with very high velocity from upstream i.e. River Eller Beck and Leeds & Liverpool Canal. When the water does not pass enough through culvert then water start to build up in front of culvert which causes flooding. This is mainly because of lack of capacity of culverts. Figure below illustrate section view of Morrison Supermarket Culverts.


Morrison supermarket and its Car park

Culvert at Morrison supermarket

Medical Centre

Bridge near Medical Centre

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Figure 11 Front view of Morrison Supermarket Culverts

3.1.1.1 Implementation of Morrison Supermarket CulvertIn order to re-solve the flooding problem at Morrison Supermarket Culvert team initially considered two options; either enlarge the culvert or raise the height of culvert to improve maximum clearance. But later decided neither action should be taken, this is because of various negative facts. Those facts were;

Option1: if team had enlarged the current culvert. Culvert would have to be excavated from one side plus join current culvert with extended part. This type of action would increase cost i.e. cost of excavation, reinforcement bar and concrete etc.

Option2: Let suppose for some reason team decided to increase the height of culvert. Again it would still cost less than enlarge the culvert. However it would affect the landscape of Morrison Supermarket Car Park.

However after careful considerations, team suggested building another culvert similar to current culvert and later cross join both of the culverts. Following figure illustrate plan of cross join.


Morrison Supermarket Culvert section view.































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Figure 12 Plan of Morrison’s Supermarket Culverts

3.1.2 What causes flooding at Medical CentreDuring the site investigation first thing team noticed was difference in the ground level such as; ground level from Medical Centre was slightly lower than the ground level at car park opposite to Medical Centre. Figure below demonstrate difference in ground level at medical centre.


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Figure 13 Location of Medical Centre

Second thing team noticed was lack of capacity of water passes beneath the current bridge and lack of flooding stopping mechanism.

Figure 14 Lack of Flooding Mechanism of River in Front of Medical Centre

So team felt that In the event of heavy raining + ice melting, this increases water level into river, the flow exceeds the capacity of river channel and starts to come out towards lower level of ground i.e. to medical centre side.

3.1.2.1 Preventing of flood at Medical CentreAfter detailed re-search team decided to build reinforcement concrete walls on river the embankment along the medical centre side and also raise level of bridge.

Increasing reinforcement concrete wall would help to stop water overflow towards medical centre not only that but also increases capacity of water in the river. Whereas raising the


Car park Opposite Medical Centre and High Ground Level

Lower Ground Level at Medical Centre.

Car Park opposite Medical Centre, Reinforcement embankment walls for flooding protections.

Medical Centre, lack of floods stopping mechanism i.e. no reinforcement embankment walls

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level of bridge this will help to increases volume of water passes under the bridge and will also resolve the blockage problem.

Figure 15 identification of weak structure at Medical Centre


Bridge level/height will be raise.

Medical Centre, floods stopping mechanism i.e. reinforcement embankment walls will be construct.

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Chapter 4

4.0 Medical Centre

4.1 Prepare a general arrangement plan for this location, showing the proposed flood defences location

4.1.1 What causes flooding at Medical CentreDuring the short trip to Skipton, team identified two major potential problems which are causing flood at the Medical Centre. First major problem that team notices was lack of capacity of water passes beneath the current bridge and lack of flooding stopping mechanism. Picture below shows river from Medical Centre with no flood stopping defences.

Figure 16 Lack of Flood Stopping Mechanism for River at Medical Centre

Second major problem was the ground level difference such as; ground level from Medical Centre was slightly lower than the ground level at car park opposite to Medical Centre. Picture below illustrate difference in ground level at medical centre.


Car Park opposite Medical Centre, Reinforcement embankment walls for flooding protections.

Medical Centre, lack of floods stopping mechanism i.e. no reinforcement embankment walls

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Figure 17 Shows Uneven Ground Surface Level

So team felt that In the event of heavy raining + ice melting, this increases water level into river, the flow exceeds the capacity of river channel and starts to come out towards lower level of ground i.e. to medical centre side.

4.2 Provide details showing the flood defences height, cross section and appearance

4.2.1 Raising Bridge

Raising the height of current bridge around half meter would be advantage, this would help the water to flow smoothly but it’s not necessary. The reason it is not necessary because of two other implementations (i.e. raising embankment walls and Channel Relief Scheme) will be enough to deal with excess amount of water.

However in the case of raising bridge height, this can be done simply by take-off the current bridge from its abutments and raising abutment (i.e. using same material as it has been used for current abutment) approximately half meter above the current height. Then later put back on same bridge over new abutments.

4.2.2 Embankments walls: The diagram below illustrates the use of a reinforced concrete floodwall which is cantilevered off the base slab, together with an integral reinforced concrete cutoff. In this case, it is disguised as boundary wall be the addition of brickwork cladding and a precast concrete coping (specially cast to resemble stone).


Car park Opposite Medical Centre with High Ground Level

Slightly Lower Ground Level from Medical Centre.

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Figure 18 shows an example of Purposed Reinforcement wall for river near medical centre

The total length of walls needed to be construct at medical centre location are 74.5735m and 44.0146 m more detailed see figure no 21. Please note that each wall height is taken to be approximately 1.5m more detailed calculations see Appendix B.

Figure 19 Shows Bird Eye-View of River at Medical Centre

Figure 20 Shows Areas Which Needed to be Strengthen Near Medical Centre


Bridge level/height will be raise.

Medical Centre, floods stopping mechanism i.e. reinforcement embankment walls will be construct.

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Advantages of raising embankment walls:

This process is quick and cheap

It is more sustainable due to the considerable usage of materials.

Minimum effect on current landscaping

Maintenance process is easy

4.3 Proposed Construction Access and Working Arrangements

4.3.1 Construction Access Skipton town is connected with number of routes and thus can be accessed from different sides. Transporting materials or heavy machinery to site the following main roads can be used;

The B6265 from the Yorkshire Dales National Park and the North. The A59 from Harrogate and York in the East and Gisburn, Clitheroe and North East

Lancashire in the West. The A65 from Ilkley, Otley and Leeds in the East and Gargrave and Settle in the West The A629 from Keighley, Bingley, Bradford, and Halifax.

On the following figure two pins coloured with red and green are representing the construction locations near to medical centre and detailed roads access can be seen as well.


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Figure 21 Plan of construction access

4.3.2 Working Arrangements

4.3.2.1 Working Arrangements for Embankment WallsDuring the refurbishment of reinforced walls both the areas of car park 1 and car park 2 can be utilized. The material will be temporarily stored in both car parking’s. The machinery required for the casting of reinforced wall is concrete pump, concrete mixer and small crane and few vibrators. During the concreting process Safety barriers to be provided around working area and one parking area can be closed temporarily while the other parking area will be in working condition and vice versa. Figure below demonstrate an example of retaining wall construction process.


January 1, 2012

Figure 22 Shows an Example of Mixer Transferring Wet Concrete on Site

4.4 Maintenance management plan proposed for the flood defencesThe purposed schemes for Medical Centre flooding are mainly; Channel Relief Scheme and Raising of Embankment Walls. As each scheme is explained above in detailed, these two schemes are very simple and designed at minimum cost. Team recommended that both schemes must be regularly checked just in case of damaged to walls or even blockage and leakage of Pre-stress-Concrete Cylinder Pipes. During the processes of suggestion of various options for medical centre, team took maintenance cost of each scheme very seriously.

In case of any pipe leakage/damaged Pre-stressed Concrete Cylinder Pipe, the effected part can be replaced and this will not have the impact on whole scheme. These (PCCP) are widely available and can be ordered as individual bock.

On the other hand in case of any damaged to the embankment wall i.e. scouring or damage of mortar. This would not cost lots of money to repair and it can be repair easily by one person at very low cost.

4.5 Climate Change Retrofit SolutionClimate change is one of the most pressing issues facing the world. Climate can be changed through the actions, especially through emissions of greenhouse gases such as carbon dioxide, which artificially warm the atmosphere of the earth. The effects of climate change include rising temperatures, higher sea levels, and more frequent extreme weather events such as floods. All of these are expected to become more severe. Future effects can be influenced by what is done now.


January 1, 2012

CALCULATE-REDUCE

Individuals are responsible for about 40 per cent of emissions in the Skipton, with energy use in the home; driving and air travel the biggest sources. Use the carbon calculator to work out how much carbon dioxide can be created individually. And then it will be easy for everyone simple, concrete ways to reduce impact on the environment and how to offset carbon footprint.

Humanity’s demands exceed our planet’s capacity to sustain. If individual or group, start by reducing consumption and carbon footprint today. Small steps can make a big difference.

WHAT IS CLIMATE CHANGE

The term ‘climate’ refers to a representation of average weather conditions, which is often described in terms of temperature and precipitation but can also include wind and other derived variables such as growing degree days. Weather is what we experience day to day. The climate of the Earth is not static; it has changed over geological and recent historic time periods, and will continue to do so into the future. It is this future anticipated change which is usually meant when the term ‘climate change’ is used.

The climate change that will occur over the next 30 to 40 years has already been largely determined by past and present emissions of greenhouse gases. Once emitted into the atmosphere these gases can last for a long time and so can influence the climate system into the future. This means that even if emissions are vastly reduced with immediate effect, the climate will continue to change in response to the legacy of emissions and adaptation measures will still be needed.

UK FUTURE CLIMATE CHANGE

Global warming due to an increasing concentration of greenhouse gases in the atmosphere resulting from human activities will have an impact on the climate therefore will affect temperature and rainfall, and hence river flows and water resources.

The nature of climate change at a regional level will vary; projections of future climate change indicate that more frequent short-duration, high-intensity rainfall and more frequent periods of long-duration rainfall of the type responsible for the 2000 floods could be expected. Sea levels will continue to rise. These kinds of changes will have implications for river flooding and also for local flash flooding.

GREEN HOUSE GASES

The most important greenhouse gases are carbon dioxide, methane, nitrous oxide, hydro fluorocarbons, perfluoracarbons and sulphur hexafluoride. These are the gases that are covered by the Kyoto Protocol.


January 1, 2012

Chlorofluorocarbons (CFCs) and hudrochlorofluorocarbons (HCFCS) are also powerful greenhouse gases but they are being progressively.

Figure 23 Shows Example of Green House Gases


January 1, 2012

Appendix: A

Design of a Retaining wall:

1) Check the stability of the wall

2) Determine the bearing pressures at the ultimate limit state.

3) Designing the bearing reinforcement using high yield steel fyk=500 KN/mm2

Values assumed

ρ = 1700 kg/m2

φ = 30

Surcharged load = 10 KN/m2

1) Stability:

Ka= (1-sin φ)/ (1+sin φ) = (1-sin30)/ (1+sin30) =0.33

Horizontal forces:

Earth pressure Pa & Surcharge pressure Ps

Pa = Ka* ρ*g*h = 0.33*1700*10-3 *9.81*1.9 = 10.45 KN/m2

Ps = Ka*10 = 0.33*10 = 3.3 KN/m2

The horizontal force on 1m length of wall is given by

Hk (earth) = 0.5*pa*h = 0.5*10.45*1.9 = 10 KN

Hk (sur) = ps*h = 3.3*1.9 = 6.27 KN

Force due to water pressure

P = (10*1.52)/2 = 11.25 KN

Vertical Loads:

(a) Permanent loads:

Wall = (1/2)*(0.3+0.4)*1.5*25 = 13.13 KN

Base = 0.4*1.9*25 = 19 KN

Earth = 1*1.5*1700*10-3*9.81 = 25 KN

Total = 57.13 KN

(b) Variable Loads:

Surcharge load = 1*10 = 10 KN

(i) Overturning: Taking moment about point A

Overturning moment = γf* Hk (earth)*h/3 + γf* Hk (sur)*h/2 + γf*p*h/2


January 1, 2012

= (1.5*10*1.9/3)+(1.5*6.27*1.9/2)-(1.5*11.25*1.9/2)

=9.5+8.93+16.03

Overturning moment = 2.4 KN-m

Restraining moment = γf *[13.13*(0.2+0.5) + 19*1.9/2 + 25*(1/2 + 0.4+ 0.5)]

= 0.9*(9.19+18.05+35)

Restraining moment = 56.01 KN

56.01/2.4 = 23.33 > 2

Thus the criteria for overturning is satisfied

(ii) Sliding: From equation it is necessary that

µ (1.0Gk+1.0Vk)> γf*Hk

For the restraining effect a factor of 1 is applied to the permanent loads and 0 to the

variable surcharge load. Assuming co-efficient of friction µ = 0.45

Sliding force = 1.35*10+1.5*6.29 = 23 KN

Frictional resistance force = 0.45*1*57.13 = 25.7 KN

25.7>23

Thus the criterion for sliding is satisfied.

(2) Bearing pressure:

P=N/D + 6M/D2

Taking moment about base centre line

M = - γf*(10*1.9/3) - γf*(6.29*1.9/2) + γf*(11.25*1.9/2) - γf*[13.13*((1.9/2)-0.7)] +

γf*[57.13*((1.9/2)-(1/2))]

= -1.35*6.33 -1.5*5.9+1.5*10.68-1.35*3.28+1*25.7

= -8.54 – 8.85 +16.02 – 4.43 + 25.7

M= 20 KN-m

P1= [(1.35*(13.13+19)+1*57.13)/1.9] + [6*20/1.92]

= 52.89+33.24

P1=86.13 KN/m2

P2=52.89-33.24


January 1, 2012

P2=19.65 KN/m2

(3) Bending Reinforcement:

(i) Wall d=300-40-10-6=194 mm

Considering the effective moment, the max moment is

MEd= γf *10*(0.2+1.5/3)+ γf*6.29*(0.2+1.5/2)

= 1.35*7+1.5*5.97

= 9.45+8.95

MEd = 18.4 KN-m

[MEd/ (b*d2*fck)]= 18.4*106/(1000*1942*30 )= 0.01

From Lever arm curve

La= z/d =0.95

As = (M/(0.87*z*fyk)) = 18.4*106/(0.87*0.95*194*500) = 229.5 mm2/m

From Table

Provide H10@250 mm centres (As=314 mm2/m)

(ii) Base

P1= 86.13 KN/m2

P2=19.65 KN/m2

P3 = 19.65+ (86.13-19.65)*(1/1.9) = 54.63 KN/m2

Heel and Toe:

Taking moment about the stem centrelines for the vertical loads and the bearing

pressures

MEd=γf *19*(1-(1.9/2)+0.2)+ γf*57.13*((1/2)+0.2)-19.65*1*((1/2)+0.2)-

- (54.63-19.67)*(1/2)*((1/3)+0.2)

MEd=1.35*40.85+1*39.99-13.75-9.32

MEd=55.14+39.99-13.75-9.32

MEd=72.06 KN-m

[MEd/ (b*d2*fck)]= 72.06*106/(1000*1942*30 )= 0.06

From Lever arm curve


January 1, 2012

La= z/d =0.95

As = (M/(0.87*z*fyk)) = 72.06*106/(0.87*0.95*194*500) = 898.8 mm2/m

From Table

Provide H12@125 mm centres (As=905 mm2/m)


1.5 m

mm

6.29KN

10 KN

11.25KN

13.13KN 19KN

57.13KN Surcharge Pressure

Active earth pressure

A

B

mm

mm

January 1, 2012

Appendix: B

BH01

Ground StrataDepth under Ground level

(m)

Grass over: Brown, clayey, organic sand with occasional rootlets. 0.00 – 0.50

Firm, brown, sandy, gravelly clay with low cobble content of sub

angular sandstone and occasional pockets of gravel. Including

sandstone and mudstone.

0.50 – 1.50

Medium dense, brown, gravelly, fine to coarse sand with medium

cobble content of sub angular sand stone, siltstone and

mudstone. Gravel is sub angular to sub rounded, fine to coarse

including sand stone, mudstone and siltstone.

1.50 – 2.10

Firm, grey/brown, sandy, slightly gravelly clay with low cobble

content of sub angular to sub rounded sandstone. Gravel is sub

angular to sub rounded, fine to coarse including sand stone,

siltstone and mudstone.

2.10 – 2.50

Soft becoming firm with depth, grey/brown, slightly sandy,

slightly gravelly clay with occasional pockets of silt.

Gravel is sub angular and sub rounded, fine to coarse including

sandstone.

2.50 – 4.50

Grey/brown, slightly sandy silt with occasional sub rounded, fine

gravel.4.50 – 5.20

Firm, grey/brown, sandy, gravelly clay with low cobble content of

sub angular to sub rounded sandstone. Gravel is sub angular to

sub rounded, fine to coarse including sand stone and siltstone.

At 7.00 m: stiff.

5.20 -12.00

Stiff, dark grey/brown Clay with high cobble content of boulders.

Cobbles are sub angular, fine to coarse including mudstone and

limestone. Gravel is sub angular to sub rounded, fine to coarse

including sandstone, mudstone and limestone.

Between 13.00m and 13.50m: high cobble/boulder content.

12.00 – 13.50


January 1, 2012

Coring from 13.00 to 13.50m to make progress.

Weak, light grey Mudstone recovered as gravel fragments

(probable cobble). 13.50 – 14.00

Very weak, grey/brown, weathered Mudstone recovered as non-

intact clayey gravel.14.00 – 15.30

Weak dark grey, highly fractures, very thinly spaced, bedded

Mudstone fractures at 045° sub horizontal.

Between 15.30 to 15.80m Sub horizontal fractured, stained

brown, moderate weathering.

Between 16.20m to 18.80m recovered as intact gravel fractures.

15.30 – 18.80

Moderately weak, trey, moderately spaced bedding horizontal

and 035° sub horizontal fractured Mudstone.

Between 19.00m and 19.17m. Vertical fractured

At 19.25m Horizontal mineral vein.

Between 19.24m and 19.35m 45° sub horizontal fracture.

18.80 – 19.50

BH02


(m)

Grass over Made ground brown, slightly clayey, organic, fine to

coarse sand0.00 – 0.5

Made ground Soft, brown/orange mottled grey, sandy, slightly

gravelly Clay with low sub angular cobble content of sandstone

and occasional pockets of gravel. Gravel is sub angular to sub

rounded, fine to coarse including siltstone and sandstone.

0.5 – 1.7

Made ground Firm dark brown mottled orange red, sandy,

slightly gravelly Clay with medium sub angular cobble content of

sandstone. Gravel is sub angular to sub rounded fine to coarse

including sandstone, mudstone and siltstone.

1.7 – 2.00

Firm, dark brown mottled red, very sandy, very gravelly clay with

high cobble content of sub angular sandstone and limestone


January 1, 2012

(possible made ground). 2.00 – 3.00

Medium dense, dark grey slightly silty, sandy gravel with low sub

angular cobble content of sandstone. Gravel is sub angular to sub

rounded fine to coarse including sandstone, mudstone, and

siltstone.

3.00 – 4.20

Very soft, grey, slightly sandy, slightly gravelly silt. Gravel is sub

angular and sub rounded coarse including siltstone.4.20 – 5.30

Soft, dark grey, slightly sandy silty clay with bands of sand.5.30 – 6.30

Firm, dark grey, slightly sandy, gravelly clay with medium cobble

content. Gravel is sub angular to sub rounded, fine to coarse of

and stone.

At 7.00m: Stiff

6.30 – 9.20

BH03


(m)

Grass over brown, slightly clayey, fine to coarse, organic sand. 0.00 – 0.10

Soft, brown/orange, sandy, gravelly clay with high cobble content

of sub angular to sub rounded sandstone and mudstone and

occasional pockets of gravel. Gravel is sub angular to sub

rounded, fine to coarse including sand stone, mudstone and

limestone.

0.1 – 2.40

Very soft, brown, slightly sandy, slightly gravelly silt. Gravel is sub

angular and sub rounded, fine to coarse including sandstone.2.40 – 2.80

Very soft, grey, sandy, clayey silt.2.80 – 4.80

Soft, grey, very sandy, gravelly clay with low cobble content of

sandstone. Gravel is sub angular to sub rounded, fine to coarse

including sandstone, siltstone, mudstone and limestone.

4.80 – 5.10


January 1, 2012

Stiff, dark grey, slightly gravelly, fine to coarse sand. Gravel is sub

angular to subr rounded, fine to coarse including sandstone,

mudstone, siltstone and limestone. With medium cobble content.

5.10 – 5.70

Very stiff, dark grey/brown, sand, gravelly clay. Gravel is sub

angular to sub rounded, fine to coarse including sandstone,

siltstone and mudstone.

5.70 – 6.00

Dense, grey/brown, fine to coarse sand. 6.00 – 6.40

Dense, grey/brown, silty, very sandy gravel with occasional bands

of clay and low cobble content of sandstone. Gravel is sub angular

to sub rounded, fine to coarse including sandstone, mudstone,

siltstone, and limestone.

6.40 – 6.70

Very stiff, grey/brown, sandy, gravelly clay with low cobbled

content of sub angular sandstone. Gravel is sub angular sub

angular to sub rounded, fine to coarse including sandstone,

mudstone and limestone.

6.70 -7.00

Dense, brown, sandy, sub angular to sub rounded, fine to coarse

gravel including mudstone and siltstone. With high cobble

content.

7.00 – 7.20

Dense, grey, gravelly, fine to coarse sand with occasional bands of

clay.7.20 - 7.60

Dark grey/black, weathered mudstone. 7.60 - 7.70

TP01


(m)

Grass over: brown, slightly, sandy, gravelly topsoil. Gravel is

angular and sub angular, fine to coarse including sandstone and

siltstone

0.00 – 0.70

Medium, locally low strength, soft, orange grey mottled, sandy,

slightly gravelly silt/clay. Gravel is angular/tabular, fine to

medium including sandstone and mudstone.

0.70 – 1.40


January 1, 2012

Below 1.20m: medium cobble and boulder content of sandstone

and siltstone.

Brown, very silty, very sandy, coarse gravel of limestone. 1.40 – 1.90

TP03


(m)

Grass over: Black, sandy, slightly clayey topsoil. 0.00 – 0.30

Medium strength, soft locally firm, grey brown, slightly sandy,

slightly gravelly clay. Gravel is angular and sub angular, fine and

medium including sandstone and mudstone.

0.30 – 1.5

Grey, silty, coarse sand. 1.50 – 1.80

Brown grey, silty, very gravelly, fine to coarse sand with

occasional cobbles. Gravel is sub angular to sub rounded, fine to

coarse including sand stone, quartz and mudstone.

1.80 – 2.10

TP04


(m)

Grass over: Dark brown, sandy topsoil. 0.00 – 0.40

Made ground: Dark grey, gravelly, medium to coarse sand. Gravel

is angular and sub angular, fine to coarse including ash, ceramic,

glass, metal, brick, sandstone, coal, mudstone and clinker.

0.40 – 2.00

Soft, grey, slightly silty, organic clay (possible made ground). 2.00 – 2.20

TP05

Ground Strata Depth under Ground level


January 1, 2012

(m)

Grass over: Brown, Clayey, sandy topsoil. 0.00 – 0.30

Light brown, clayey, slightly gravelly, medium sand with

occasional rootlets. Gravel is sub angular to sub rounded, fine to

coarse including sandstone, quartz and limestone.

0.30 – 0.80

Firm, brown, slightly gravelly, silty, fine sand with occasional

rootlets.0.80 - 1.10

Brown, clayey, sandy, sub angular to sub rounded, fine to coarse

gravel with medium cobble content of limestone.1.10 – 1.60

Low strength, firm locally soft, brown, slightly sandy, gravelly clay.

Gravel is sub angular to sub rounded, fine to coarse including

sandstone and limestone.

Below 2.40m: medium boulder content.

Between 2.50m and 2.70m: sand lense.

1.60 – 3.10


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