Iniskeen - North West – Neagh Bann CFRAM Study

Transcription

NWNB CFRAM Study
HA06 Hydraulics Report (Inniskeen) - DRAFT FINAL
NWNB CFRAM
Study
HA06 Hydraulics Report
Inniskeen Model
DOCUMENT CONTROL SHEET
Client
OPW
Project Title
NWNB CFRAM Study
Document Title
IBE0700Rp0012_HA06 Hydraulics Report
Model Name
Inniskeen
Rev
.
Status
Author(s)
D01
Draft
Various
T. Ballentine
M.Wilson
F01
Draft
Final
J. Murdy
T. Donnelly
F02
Draft
Final
J. Murdy
T. Donnelly
IBE0700Rp0012
Modeller
Reviewed by
Approved By
Office of Origin
Issue Date
S. Patterson
G. Glasgow
Limerick/Belfast
12/06/2014
T. Donnelly
J. Murdy
J Canavan
S. Patterson
G. Glasgow
Belfast
16/03/2015
T. Donnelly
J. Murdy
J Canavan
S. Patterson
G. Glasgow
Belfast
13/08/2015
Rev F02
HA06 Hydraulics Report (Inniskeen) – DRAFT FINAL
NWNB CFRAM Study
Table of Reference Reports
Report
Issue
Date
Report Reference
North Western Neagh Bann
CFRAM Study Flood Risk Review
May 2012
2011s5232 NW&NB CFRAM FRR
Report_Final_v2.0
CFRAM Study UoM06 Inception
Report
March
2013
IBE0700Rp0003_UoM 06 Inception Report_F02
4.3.2
October
2013
IBE0700Rp0008_UoM 06 Hydrology
Report_F01
4.5
October
2013
IBE0700Rp0007_HA01_06_36
NWNB_CFRAM_Survey Contract Report F01
CFRAM Study Hydrology Report
UoM06
CFRAM HA01_06_36 Survey
Contract Report
4
Relevant
Section
Hydraulic Model Details.................................................................................................................... 1
4.2
Inniskeen model ...................................................................................................................... 1
4.2.1
General Hydraulic Model Information .................................................................................. 1
4.2.2
Hydraulic Model Schematisation ......................................................................................... 2
4.2.3
Hydraulic Model Construction ............................................................................................ 10
4.2.4
Sensitivity Analysis ............................................................................................................ 22
4.2.5
Hydraulic Model Calibration and Verification ..................................................................... 23
4.2.6
Hydraulic Model Assumptions, Limitations and Handover Notes ...................................... 28
IBE0700Rp0012
Rev F02
NWNB CFRAM Study
4 HYDRAULIC MODEL DETAILS
4.2
4.2.1
INNISKEEN MODEL
General Hydraulic Model Information
(1) Introduction:
The NWNB CFRAM Flood Risk Review (2011s5232 NW&NB CFRAM FRR Report_Final_v2.0) highlighted
Inniskeen as an AFA for fluvial flooding based on a review of historic flooding and the extents of flood risk
determined during the PFRA.
The River Fane is the main watercourse that flows through the Inniskeen AFA (refer to Section 4.2.4,
Figure 4.2.1). From the village of Inniskeen, the River Fane flows in south-easterly direction for
approximately 20km before discharging into Dundalk Bay. The entire Fane system starts at the upstream
end of Lough Muckno (located east of Castleblayney). The Clarebane River flows between Lough Muckno
and Lough Ross, which is located on the boundary of Northern Ireland. From here, the River Fane flows
from Lough Ross and then back through the Republic of Ireland. The River Fane system has been heavily
utilised to supply water to several locations, north and south of the border. These areas include Monaghan
County, Newry and Mourne as well as Dundalk and its surrounding hinterland. Since the late 1980's, a low
flow augmentation scheme has ensured that these areas have been supplied with an adequate supply of
water. Prior to the development of this scheme, low flow rates where often experienced as a direct
consequence of significant abstraction levels and the system’s inability to replenish. Two tributaries of the
River Fane (the Inniskeen and the Lannat) are also part of the Inniskeen model, entering the River Fane
within the AFA. In addition four small unnamed tributaries (called Tributary 1 to 4) are included within the
model as shown on Figure 4.2.1.
2
The Fane catchment area at the downstream limit of the Inniskeen model is 338km . The catchment area
2
of the River Fane at Moyles Mill (upstream of Inniskeen AFA) is 229km .
Hydrometric station 06011 (Moyles Mill), is an A1 station operated by OPW with 40 years of data. It is
located at the upstream extent of the Model on the River Fane and has been used as a pivotal site for
adjusting initial Qmed estimates with an adjustment factor of 0.86. Qmed values for the modelled tributaries
were not adjusted as they are not hydrologically similar. These tributaries are generally much smaller (less
than 5% of the catchment for tributaries directly affecting the AFA) and are not directly affected by the
attenuation effect of Lough Muckno. Full details of hydrological analysis for this model are included in
UoM 06 Hydrology Report (IBE0700_Rp0008_F01).
The River Fane (0613M) is HPW as it flows through the AFA, and is MPW along the modelled reaches
upstream and downstream of the AFA extents. Upstream of the AFA the MPW reach runs from chainage
-23m to 1851m. Downstream of the AFA the MPW reach runs from chainage 4540m to 22097m. The
HPW portion of the River Fane runs between chainage 1851m and 4540m (within the AFA). All modelled
tributaries are HPW. HPWs have been modelled as 1D-2D using the MIKE suite of software. The MPW
IBE0700Rp0012
4.2-1
Rev F02
NWNB CFRAM Study
reaches of the River Fane have been modelled as 1D only. The 1D and 2D hydrodynamic models were
integrated into one modelling system using MIKE FLOOD. This method has allowed the modelling of the
model domain in 1D detail and the surrounding area beyond the main channels in 2D. For watercourses
which are modelled in 1D/2D the rising water levels spill onto the 2D domain from the 1D cross-sections.
This occurs at bank markers set per cross section in the MIKE 11 software. The markers are generally set
at the highest point of the river bank.
(2) Model Reference:
HA06_INIS5
(3) AFAs included in the model:
INNISKEEN
(4) Primary Watercourses / Water Bodies (including local names):
Reach ID
Name
0613M
FANE RIVER
0613A
FANE RIVER TRIBUTARY 1
0613B
0613C
0613D
0614M
INNISKEEN
0615M
LANNAT
The above spellings are a direct reference to the survey data which is used in the model.
(5) Software Type (and version):
(a) 1D Domain:
(b) 2D Domain:
(c) Other model elements:
MIKE 11 (2011)
MIKE 21- Rectangular Mesh
MIKE FLOOD (2011)
(2011)
4.2.2
Hydraulic Model Schematisation
(1) Map of Model Extents:
IBE0700Rp0012
4.2-2
Rev F02
NWNB CFRAM Study
Figure 4.2.1: Inniskeen Model Overview
IBE0700Rp0012
4.2-3
Rev F02
NWNB CFRAM Study
Figure 4.2.2: Inniskeen Model - AFA Extent
Figures 4.2.1 and 4.2.2 illustrate the extent of the model, river centre line, HEP locations and AFA extent.
The model contains 3no. Upstream Limit HEPs (representing the River Fane, Lannat and Inniskeen), 1no.
Downstream Limit HEP at Dundalk Bay, and 7no. Tributary HEPs. There are 5no. Intermediate HEPs.
Gauging Station HEP (Moyles Mill, 06011_RA denotes the upstream limit of the Inniskeen Model and as
such was used for derivation of design flows (refer to UoM 06 Hydrology Report and Section 4.2.3(5) of
this report. Castlering and Stephenstown Gauging Stations (Stn no. 06057 and 06035 respectively) have
no associated water level or flow data and so were redefined as Intermediate HEPs. The Intermediate
and Downstream Limit HEPs were used in the anchoring of model results to hydrological estimates (refer
to Appendix A.3). The downstream node 06_977_3_RA on the River X was used a model inflow point
instead of the Upstream Limit HEP 06_997_2_RA (refer to Section 4.2.3(5)).
(2) x-y Coordinates of River (Upstream extent):
IBE0700Rp0012
Reach ID
Name
x
y
0613M
FANE RIVER
291816.00
308663.03
0613A
303410.48
300548.72
0613B
293351.82
307002.01
0613C
293748.10
306797.12
0613D
293680.80
306816.30
0614M
INNISKEEN
293446.34
307440.66
4.2-4
Rev F02
NWNB CFRAM Study
0615M
LANNAT
(3) Total Modelled Watercourse Length:
(4) 1D Domain only Watercourse Length:
292876.00
307466.24
26km
19.9km
(5) 1D-2D Domain
6.1km
Watercourse Length:
(6) 2D Domain Mesh Type / Resolution / Area:
Rectangular / 5 metres / 13.4km
2
(7) 2D Domain Model Extent:
Modelled River Centreline
AFA Boundary
Figure 4.2.3: 2D Domain Model Extent
Figure 4.2.3 provides an illustration of the modelled extents and the general topography of the Inniskeen
model. The entire area represents the 2D extent of the model. The spatial extent of the AFA boundary is
outlined in red, whereas the reach centrelines are illustrated in blue. Figure 4.2.3 also represents the 1D
modelled extent that is within the 2D area. Buildings are excluded from the mesh and therefore
represented as small white spaces - refer to Chapter 3.3.2 for details on representation of buildings in the
model.
Error! Reference source not found. shows an overview drawing of the model schematisation for
Inniskeen. Figure 4.2.5 and
Figure 4.2.6 show detailed views. Figure 4.2.5, the overview diagram
illustrates the model extents, showing the surveyed cross-section locations, AFA boundary and river
centreline. It also shows the area covered by the 2D model domain. The more detailed views are provided
as examples of where there is the most significant risk of flooding. They include the surveyed crosssection locations, AFA boundary and river centreline. They also show the location of the critical structures
along with the location and extent of the links between the 1D and 2D models. For clarity in viewing crossIBE0700Rp0012
4.2-5
Rev F02
NWNB CFRAM Study
section locations, the model schematisation diagram shows the full extent of the surveyed cross-sections.
Note that the 1D model considers only the cross-section between the 1D-2D links.
Figure 4.2.4: Overview of Model Schematisation
IBE0700Rp0012
4.2-6
Rev F02
NWNB CFRAM Study
Figure 4.2.5: Overview of Model Schematisation - AFA Extent
IBE0700Rp0012
4.2-7
Rev F02
NWNB CFRAM Study
Figure 4.2.6: Detailed Area of Model Schematisation (AFA Critical Structures)*
Figure 4.2.7: Detailed Area of Model Schematisation (Upstream River Fane)*
IBE0700Rp0012
4.2-8
Rev F02
NWNB CFRAM Study
* For clarity in viewing cross-section locations, the model schematisation diagram shows the full extent of the surveyed crosssections. Note that the 1D model considers only the cross-section between the 1D-2D links.
(8) Survey Information
(a) Survey Folder Structure:
First Level Folder
Second Level Folder
Murphy_NW6_M05_WP1_V2_0613M_130
V0_20130306_Ascii
718
V0_20130306_GIS
Inniskeen
Third Level Folder
Flood_Plain_Photos_and_Shap
efile
Murphy: Surveyor Name
Structure_Register
NW6: NWNB CFRAM Study Area,
Surveyed_Cross_Section_Lines
Hydrometric Area 6
Watercourse_Register
M05: Model Number 05
0613M: River Reference
V0_20130306_Other
WP1: Work Package 1
Photos (Naming
V2: Version
convention is in the
th
130718: Date Issued (18 JUL 2013)
Floodplain Photos
format of Cross-Section
ID and orientation upstream, downstream,
left bank or right bank)
(b) Survey Folder References:
Reach ID
Name
File Reference
0613M
FANE RIVER
Murphy_NW6_M05_WP1_V2_0613M_130718
0613M
FANE RIVER
Murphy_NW6_M05_WP6A7_0613M_V1_130315
0613M_A
FANE RIVER
Murphy_NW6_M05_WP6_0613M_A _V1 _130329
0613M_B
FANE RIVER
Murphy_NW6_M05_WP6_0613M_B_V2_130718
0613A
FANE RIVER TRIB 1
Murphy_NW6_M05_WP6_0613A _V1 _130329
0613B
FANE RIVER TRIB 2
Murphy_NW6_M05_WP6_0613B _V1 _130329
0613C
FANE RIVER TRIB 3
Murphy_NW6_M05_WP6_0613C _V1 _130329
0613D
FANE RIVER TRIB 4
Murphy_NW6_M05_WP6_0613D _V1 _130329
0614M
INNISKEEN
Murphy_NW6_M05_WP6_0614M_V1_130315
0615M
LANNAT
Murphy_NW6_M05_WP6_0615_V1_130315
(9) Survey Issues:
Several minor survey queries relating to Inniskeen model were raised. All queries are outlined below have
IBE0700Rp0012
4.2-9
Rev F02
NWNB CFRAM Study
been resolved.

At cross-section 0613M02124X, it was indicated on the original survey drawing that a fish pass
was observed but not surveyed (due to health and safety concerns). Following a survey query
this cross-section was re-surveyed to include a complete cross-section under safe conditions;

Several cross-sections along the Fane River including 0613M02118, 0613M02088, 0613M02081,
0613M02080, 0613M02078, 0613M02073, 0613M02068, 0613M02063 and 0613M01900X were
not completely surveyed due to fast flowing water.
Following a survey query, the surveyors
completed these cross-sections under safe conditions.

Additional survey points and cross-sections were requested to improve the calibration between
the model and Moyles Mill gauging station, Q-H relationship (Rating Review) – refer to Section
4.2.4(4) for further details.
4.2.3
Hydraulic Model Construction
(1) 1D Structures (in-channel along modelled
See Appendix A.1
watercourses):
The hydraulic structures defined within the river network
are listed as follows
Bridges and Culverts: 23
Weirs: 4
Several critical structures were identified in the model; they are presented below see Figure 4.2.8 to 4.2.15
inclusive. The survey information recorded includes a photograph of each structure, which has been used to
determine the Manning's n value. Further details are included in Chapter 3.5.1. A discussion on the way
structures have been modelled is included in Chapter 3.3.4. Critical structures are as follows.
Figure 4.2.8 below show the River Lannat culvert 0615M00026I (chainage 288m to 540m) at its upstream
opening. Model results show that this circular culvert restricts flood flow during a 0.1% AEP fluvial event and
that out of bank flooding initially occurs on the right (west) bank (chainage 268m) upstream of this structure.
The 0.1% AEP fluvial flood event causes ponding upstream from this structure and into an area of agricultural
fields. Flood waters then flow in a downstream direction (SSE) towards the River Fane.
IBE0700Rp0012
4.2-10
Rev F02
NWNB CFRAM Study
Figure 4.2.8: Culvert 0615M00026I, River Lannat
Figure 4.2.9 below shows Inniskeen River, culvert 0614M00053I (chainage 29.592m). This circular culvert
(diameter 0.9m) is located close to the modelled upstream extent of the Inniskeen River. Due to the presence
and restrictive capacity of this culvert, flood waters accumulate upstream during 10%, 1% and 0.1% AEP
modelled fluvial events. During the 1% and 0.1% AEP events, flood waters spread out into an area that is the
site of Lisarolagh Fort and appears to be an area of woodland, no residential properties are affected.
Figure 4.2.9: Culvert 0614M00053I, Inniskeen River
A stone arch bridge (0613M02144D) (chainage 659m) shown below in Figure 4.2.10 is located upstream of
the Inniskeen AFA on a meander of River Fane. This bridge is part of the old Great Northern Railway route.
Model results indicate that the bridge restricts flood flow during 1% and 0.1% AEP fluvial flood events with
causing flooding on the left bank (east) of the River Fane, into an area of agricultural land. No properties are
IBE0700Rp0012
4.2-11
Rev F02
NWNB CFRAM Study
affected. Another bridge also known 'Fane River Bridge' is located downstream (chainage 18190m).
Figure 4.2.10: Old Railway Bridge 0613M02144D
Figure 4.2.11 shows Inniskeen (road) Bridge (0613M01906D) (chainage 3049m) which is located within the
centre of Inniskeen AFA. This structure has insufficient capacity during the modelled 1% and 0.1% AEP
fluvial events causing flooding to Deery's Terrace (housing).
Figure 4.2.11: Inniskeen Bridge (0613M01906D)
Figure 4.2.12 shows Knock Bridge (0613M01031D) (chainage 11807m), where the R171 crosses the River
Fane. Model results show that the bridge restricts flow during 10%, 1% and 0.1% AEP fluvial events. This
causes flooding upstream of the bridge on the right bank (west). Several agricultural buildings located within
this area are affected.
IBE0700Rp0012
4.2-12
Rev F02
NWNB CFRAM Study
Figure 4.2.12: Knock Bridge (0613M01031D)
Figure 4.2.13 shows Stephenstown (road) Bridge (0613M00702D) (chainage 15089m).
This triple-arch
structure is located where the N52 crosses the River Fane. Model results show that flood flow is restricted
during the 10%, 1% and 0.1% AEP fluvial events. The agricultural fields immediately upstream of this bridge,
particularly on the right bank (south) are susceptible to flooding.
On the left bank, approximately 30m
upstream from this bridge, a large property is at risk of flooding.
Figure 4.2.13: Stephenstown Bridge (0613M00702D)
The Fane River Bridge (0613M00392D) (chainage 18190m) shown in Figure 4.2.14, is located on the
Commons Road where it crosses over the River Fane. This road bridge restricts flood flow during modelled
1% and 0.1% AEP fluvial events causing flooding close to the upstream face of the Stephens Town Bridge.
IBE0700Rp0012
4.2-13
Rev F02
NWNB CFRAM Study
Figure 4.2.14: Fane River Bridge (0613M00392D)
Figure 4.2.15 shows a bridge on the River Fane 0613M01588D (chainage 6227m). Model results show that
this structure contributes to a significant amount of flooding during 10%, 1% and 0.1% AEP events. Adjacent
agricultural fields and several farm buildings, located on the right (west) bank are affected by flooding.
Evidence of debris accumulation e.g. tree trucks and branches, as shown in the Figure 4.2.15 is reflective of
the restrictive nature of this structure.
Figure 4.2.15: River Fane Structure (0613M01588D)
(2) 1D Structures in the 2D domain (beyond
None
the modelled watercourses):
IBE0700Rp0012
4.2-14
Rev F02
NWNB CFRAM Study
(3) 2D Model structures:
None
(4) Defences:
Type
Watercourse
Bank
Model
Start
Model
Chainage
Chainage
(approx.)
(approx.)
End
None
(5) Model Boundaries - Inflows:
Full details of the flow estimates are provided in the Hydrology Report (IBE0700Rp0008_UoM 06 Hydrology
Report_D01, Section 4.5 and Appendix D). The boundary conditions implemented in the model are shown
Table 4.2.1.
Table 4.2.1: Inniskeen Model Boundary Conditions
Following initial model simulations, the flow outputs at HEP check points were compared with hydrological
estimates.
Following hydrological investigation it was necessary to adjust the timing of some inflow
hydrographs (for tributaries entering modelled reaches) to alter the occurrence of peak flow and achieve
anchoring of the model to estimated / observed flows. The timing was either delayed or increased within the
model as listed in Table 4.2.2. Full details of hydrological analysis are included in UoM 06 Hydrology Report
(Rp008_F02).
Table 4.2.2: Timing Adjustment of Inflow Hydrographs to achieve Model Anchoring
River Name
HEP
Type
Description
Timing Adjustment
Fane
06_905_17_RA
Trib (point
source)
Tributary entering River Fane
(chainage 1123.54m)
delayed by 12 hours
Lannat
06_345_U_RARPS
Inflow
Lannat (upstream extent)
delayed by 6 hours
Lannat
Top-up between
06_345_U_RARPS
&
06_345_1_RARPS
Lateral
inflow
Lannat (chainage 0 to
548.051m)
delayed by 6 hours.
Inniskeen
06_997_3_RA
Inflow
Replacement to
06_997_2_RA – see text
below
delayed by 19 hours.
IBE0700Rp0012
4.2-15
Rev F02
NWNB CFRAM Study
Fane
06_229_4_RA
Trib. (point
source)
(chainage 9520.68m)
Fane
06_870_8_RA
Trib. (point
source)
(chainage 10502.4m)
Fane
06_376_5_RA
Trib. (point
source)
(chainage 17990.5m)
06_979_2_RA
Trib. (point
source)
_Trib 1 (chainage 629.377m)
On the Inniskeen modelled tributary the design flow at HEP 06_997_3_RA was used as an inflow at the
upstream HEP 06_997_2_RA. This was done rather than inserting a nominal upstream inflow and a very
small lateral inflow and is justified since the difference in the catchment area between these HEPs is
negligible.
Figure 4.2.16 provides an example of the upstream input hydrograph (1% AEP) on the River Fane
(06011_RA) River Lannat (06_345_U_RARPS) and River Inniskeen (06_997_3).
Figure 4.2.16: Upstream hydrographs relating to the Inniskeen Model (1% AEP)
IBE0700Rp0012
4.2-16
Rev F02
NWNB CFRAM Study
Derivation of these hydrographs is detailed in the UoM 06 Hydrology Report (IBE0700_Rp0008, Chapter 6).
The inflow hydrograph at Station 06011 on the River Fane was derived using the FSU Hydrograph Shape
generator tool (FSU WP 3.1) and verified against plotted hydrographs for extreme events in the recorded
dataset. For example, the observed November 2009 event hydrograph from the Moyle’s Mill gauging station,
estimated to have had a flood frequency of approximately 1% AEP, was compared to the 1% AEP design
hydrograph at the upstream inflow. Comparison of the November 2009 plotted hydrograph (Figure 4.2.17)
indicates that the design shape is generally reflective of the observed event, in terms of width and time to
peak whilst ensuring model stability by providing a regular shape, free from the erratic multiple peaks of the
particular recorded event.
Figure 4.2.17: Station 06011 (Moyles Mill) Comparison of 1% AEP Design Event Hydrograph with
November 2009 Event
The smaller hydrographs for modelled tributaries were generated using FSSR 16 Unit Hydrograph method as
2
catchment areas are less than 10 km .
(6)
Model
Boundaries
Downstream Conditions:
–
A water level boundary was applied to the downstream extent of the
Fane River at the point of discharge into Dundalk Bay (Fane River
chainage 22097.35) see Figure 4.2.18. The downstream extent of the
River Fane has been modelled in 1D only. The water-level boundary
applied to this location is a simulation of diurnal tidal conditions,
combined with a surge residual component, which together form a Total
Water Level (TWL). A tidal water boundary was applied instead of a Q-h
relation based on the information extracted from the 'Site Assessment'
IBE0700Rp0012
4.2-17
Rev F02
NWNB CFRAM Study
(http://nwnb.cfram.com/wp-content/uploads/2011/10/2011s5232-SiteAssessment-Co-Louth_web.pdf). It is noted that high tide floods land
along the River and the River Fane is tidal to Stephenstown Bridge.
It should also be noted that an outlet reach was added to the model to
allow the 0.1% AEP flood to leave the 2D domain and prevent unrealistic
water depths at the northern boundary. A constant water level of 59.19
mOD Malinhead was applied to both the upstream and downstream
cross-sections of the outlet reach. The constant water level is an initial
'dummy' value set only slightly greater than the bed level of the cross
sections. The value is ignored once the flood extents reach the outlet,
which is connected to the 2D domain by a standard link. The level of the
boundary varies in time based on dynamic calculations driven by the
flood extents.
A 'water-level' boundary that was reflective of a TWL was applied to the downstream extent of the River Fane
(22097m) to reflect the influence of coastal water levels upon fluvial flooding scenarios. This TWL has been
calculated using predicted tidal levels combined with the surge residual.
Outputs from the ICPSS have resulted in extreme tidal and storm surge water levels being made available
around the Irish Coast for a range of AEPs. ICPSS node NE_04 (Irish Grid ref. -6.35394_53.95552) was used
to generate extreme water levels close to the downstream end of the Fane River in Dundalk Bay. The location
of this ICPSS node relative to the Fane River can be seen in Figure 4.2.18 with associated AEP water levels
listed in Table 4.2.3. Figure 4.2.19 shows the Total Water Level profile that was applied to the downstream of
the Inniskeen model.
IBE0700Rp0012
4.2-18
Rev F02
NWNB CFRAM Study
Figure 4.2.18: Geographical Position of ICPSS Nodes
Table 4.2.3: ICPSS AEP Total Water Levels for Relevant Model Node –
Annual Exceedance Probability (AEP) %
50
ICPSS Node
NE04
20
10
5
2
1
0.5
0.1
Highest Tidal Water Level to OD Malin (m)
3.0
3.2
3.3
3.4
3.5
3.6
3.7
3.9
The ICPSS water levels are total water levels, comprising tidal and surge components which together yield a
joint probability event of a particular AEP.
Using information from the Secondary Ports of Dunany Point and Soldiers Point in the Admiralty Tide Tables;
RPS established a tidal water level approaching Mean High Water Springs (MHWS). This tidal level is
representative of Dundalk Bay.
A surge component is added to produce a total water level for the relevant
%AEP. The astronomic tide level was calculated to be 1.75m OD Malin and is equivalent to a tide half way
between a Mean High Tide (MHT) and a MHWS.
Tidal profiles were extracted from the RPS Irish Seas model and scaled using the established tidal water
level. The tidal curve was combined with the appropriate scaled residual surge profile of 48 hours duration to
obtain the total combined water level time series as required for the relevant AEPs see Figure 4.2.18.
IBE0700Rp0012
4.2-19
Rev F02
NWNB CFRAM Study
Figure 4.2.19: Total Water (Tide and Surge) Level Profiles for the Inniskeen Model Boundary at 50%
AEP
(7) Model Roughness: (see Section 3.4.1 'Roughness Coefficients')
(a) In-Bank (1D Domain)
Minimum 'n' value: 0.040
Maximum 'n' value: 0.070
(b) MPW Out-of-Bank (1D)
Minimum 'n' value: N/A
Maximum 'n' value: N/A
(c) MPW/HPW Out-of-Bank
Minimum 'n' value: 0.034
Maximum 'n' value: 0.059
(2D)
(Inverse of Manning's 'M')
(Inverse of Manning's 'M')
IBE0700Rp0012
4.2-20
Rev F02
NWNB CFRAM Study
Figure 4.2.20: Map of 2D Roughness (Manning's n)
Figure 4.2.20 shows the roughness values applied within the 2D domain of the model. Roughness in the 2D
domain was applied based on land type areas defined in the Corine Land Cover Map with representative
roughness values associated with each of the land cover classes in the dataset. Null Manning's M (1/n) value
on inland water bodies were corrected to Manning's n of 0.033. The bed resistance in the MIKE 21 model is
defined by the HA06_INIS5_Corine.dfs2; this file is a spatially distributed map of roughness values in the
floodplain.
(d) Examples of In-Bank Roughness Coefficients
Roughness coefficients for cross-sections and structures within 1D river models were taken from the CIRIA
(1997).
Through a combined means of photography, videos and topography survey information, an
appropriate Manning's n value was selected for each cross-section. Examples relating to the Inniskeen
model are provided below, Figure 4.2.21 to 4.2.24, inclusive.
IBE0700Rp0012
4.2-21
Rev F02
NWNB CFRAM Study
Figure 4.2.21: Fane River - 0613M2013_UP
Figure 4.2.22: Inniskeen - 0614M00044_UP
Manning's n = 0.040
Manning's n = 0.040
Clean winding stream with some pools, shoals and
Weeds.
Weeds.
Figure 4.2.24: Fane River Tributary 1 -
Figure 4.2.23: Lannat - 0615M00034_UP
0613A00174D_UP
Manning's n = 0.045
Clean, winding stream with some pools and shoals,
Manning's n = 0.040
and some weeds and stones.
Weeds.
4.2.4
Sensitivity Analysis
To be completed for final version of report.
IBE0700Rp0012
4.2-22
Rev F02
NWNB CFRAM Study
4.2.5
Hydraulic Model Calibration and Verification
(1) Key Historical Floods (From IBE0700Rp0003_UoM 06 Inception Report_F02 unless otherwise
specified):
(a) Recurring
Flooding incidents in Inniskeen have been described as 'recurring' in the 'Meeting
Minutes of the Carrickmacross Area Engineer' (see www.floodmaps.ie). This source
has stated that the River Fane has a tendency to overflow its banks every second
year as the consequence of heavy rainfall. Several spatial references have been
provided, these include
1. School (St Daigs) playing fields,
2. Pitch & putt course,
3. Residential properties.
Although these 'recurring' flooding events generally equate to a 50% AEP, the above
listed spatial references are useful for verifying the modelled flood extents at the 10%
AEP fluvial scenario which has been modelled to date. Figure 4.2.25 shows the 10%
AEP modelled flood extents and spatial references 1, 2 and 3 as listed above.
No other information regarding the date or duration of these flooding events is
available. It is not possible to associate these 'recurring' flooding events with a
particular rainfall event.
IBE0700Rp0012
4.2-23
Rev F02
NWNB CFRAM Study
Figure 4.2.25: Modelled 10% AEP Fluvial Flood Extents
(b)
November
2009
Comments presented in NWNB CFRAM Study_Progress Report No.10, refer to the
occurrence of a flooding event in Inniskeen during 2009. Gleneven Guesthouse and
The Mill were flooded. Gleneven Guesthouse and The Mill are located between the
Fane River and a Fane River Tributary 2 see Section 4.2.5(5)(b). Data obtained from
the Moyles Mill (06011) gauging station provides evidence that the largest peak flow
3
recorded by this gauge was 34m /s 19/11/2009 (see Figure 4.2.17).
This
approximately equates to a 1% AEP fluvial event based on an FSU at site flood
frequency analysis of the 56 years of AMAX flow data which are available (post rating
review).
Figure 4.2.26, show the Draft Final model results at a 1% AEP level, the spatial
references provided by the 'Progress Report' have been highlighted, showing flooding
in and around Gleneven Guesthouse and The Mill.
IBE0700Rp0012
4.2-24
Rev F02
NWNB CFRAM Study
Figure 4.2.26: Modelled 1% AEP Fluvial Flood Extents
Summary of Calibration
Available historic flooding reports referring to Inniskeen, generally describe how the River Fane overflowed
its banks every second year following heavy rain. The historical information that has been presented
generally refers to low magnitude, high frequency fluvial flooding events, i.e. approximately 50% AEP.
Three spatial flooding references were compared with the lowest modelled flooding scenario of 10% AEP
to show a good comparison, see Figure 4.2.25.
During November 2009, it was reported that a more extreme flooding event occurred. Moyles Mill (06011)
3
hydraulic gauging station recorded a peak flow of 34m /s, which approximates to a 1% AEP fluvial flooding
event (refer to Figure 4.2.17). The 1% AEP fluvial event scenario model results were compared with this
report to show that The Mill and Gleneven House are affected by flooding see Figure 4.2.26. According to
the modelled flood extents, flooding also occurs within this area during a 10% AEP fluvial flooding
scenario. In summary, the modelled results compare well with the descriptions of historic event flooding,
therefore providing model verification.
Met Eireann have described November 2009, as being notable for high rainfall and the cause of severe
flooding experienced in many parts of the country. Rainfall totals for November were the highest on
record at most stations see http://www.met.ie/publications/Rainfall%20November%202009.pdf. Therefore
flood mechanism associated with fluvial flooding in Inniskeen is prolonged and heavy rainfall. No recent
localised rainfall data was obtained to make an assessment of rainfall event frequency. Several rain
gauge stations were checked including Inniskeen, Louth, Knockbridge and Hackballcross, none of which
IBE0700Rp0012
4.2-25
Rev F02
NWNB CFRAM Study
record data beyond 2006.
Model flows were checked against the estimated flows at HEP check points where possible to ensure the
model is well anchored to the hydrological estimates. For example, at HEP 06_92_1_RA on the Fane
3
River, the estimated flow during the 1% AEP event is 33.43 m /s (IBE0700Rp0008_UoM 06 Hydrology
3
Report_F01, Appendix D) and the modelled flow is 36.6 m /s. Full flow tables and discussion of
comparison results are in Appendix A.3
A mass balance check has been carried out on the model to make sure that the total volume of water
entering and leaving the model at the upstream and downstream boundaries balances the quantity of
water remaining in the model domain at the end of a simulation. Refer to Chapter 3.11 for details of
acceptable limits. Results produced a difference of 2% which is acceptable so the model is considered to
be robust and stable.
The rating curve and spot gaugings at the Moyles Mill (06011) were used to calibrate the model results.
The results of this exercise are presented in Section 4.2.5(4) of this report.
(2) Public Consultation Comments and Response:
PCD to be completed for final version of report
To be completed.
(3) Standard of Protection of Existing Formal Defences:
Defence
Type
Watercourse
Reference
Bank
Modelled Standard
of Protection (AEP)
None
(4) Gauging Stations:
a) Moyles Mill (06011) is an A1 gauging station with 48 years of water level and flow data. It is located on
the River Fane, upstream from the north-western extent of the AFA boundary and 2km upstream from the
Lannat River Tributary confluence. A rating review was conducted for this station (refer to UoM 06
Hydrology Report Rp0008 Chapter 3). Figure 4.2.27 presents the modelled rating curve plotted against
the existing OPW rating. OPW spot gaugings, pre and post 1981 are also included on this plot.
In an attempt to improve the relationship between the modelled and the low flow spot gaugings, an infill
survey was commissioned to find a low flow control point. Several additional cross sections were also
added to the model (see Section 4.2.2(9)). However even with the addition of further survey information
the shape of the lower curve did not alter significantly. The modelled rating curve, spot gaugings and
second OPW derived rating equation (from approximately 0.8m up to 1.5m) shows a close comparison. A
good comparison is also evident between the modelled curve and the higher post 1981 spot gaugings.
Several adjustments were made to the model parameters in order to improve the low flow model results
without much success. Supportive of the validity of the modelled results, it should be recognised that the
spot gaugings used to derive the original OPW rating curve are old. The most recent spot gaugings were
taken at least 15 years ago. Consequently, any change made to the river channel at or within a close
IBE0700Rp0012
4.2-26
Rev F02
NWNB CFRAM Study
proximity to this point that has significantly altered the Q-h relationship will not have been recorded. It is
strongly recommended that several new spot gaugings are recorded.
Figure 4.2.27: Comparison between RPS Model and Existing Rating Curve – Stn 06011.
(b) Castlering Hydrometric Station (06057_RA) is located downstream from the Inniskeen AFA, this
gauging station has no data available.
(c) Stephenstown (06035_RA), also located downstream from the Inniskeen AFA, this gauging station has
no data available.
(5) Other Information:
a) OPW Flood Hazard Mapping - Phase 1. Monaghan County Council - Oral Report - Area Engineer Carrickmacross minutes of meeting from 08/11/05.
The minutes note that the River Fane overflows its banks every second year after heavy rain. The pitch
and putt course and the sewerage works are liable to flood. This report also noted that a 'property' was
also affected. A North-West and Neagh-Bann Flood Risk Review (2011s5232NW&NB CFRAM FRR
Report_Final_v2.0) has mentioned that a total of three properties were at risk, including one school. A
comparison of these reports with model outputs was made using the lowest modelled AEP fluvial event
(10%), see Section 4.2.5 and Figure 4.2.25 & 4.2.26.
b) NWNB CFRAM Study_Progress Report No.10.
Comments were received regarding Gleneven Guesthouse and The Mill which are located between the
Fane River and a Millrace. It was noted that these areas flooded in 2009. Model results show that the
IBE0700Rp0012
4.2-27
Rev F02
NWNB CFRAM Study
Gleneven Guesthouse and Inniskeen Mills flooding during a 10%AEP fluvial flooding event.
c)
Site
Assessment
see
(http://nwnb.cfram.com/wp-content/uploads/2011/10/2011s5232-Site-
Assessment-Co-Louth_web.pdf); has noted that high tides flood land along the River Fane. The River
Fane is tidal to Stephenstown Bridge). It was also noted that the N52 has been flooded to depths of 50cm
and 100cm.
4.2.6
Hydraulic Model Assumptions, Limitations and Handover Notes
(1) Hydraulic Model Assumptions:
(a) The survey report suggests the Fane River Tributaries 2 (0613B) was filled in at the upstream end so
the no water can flow from the main Fane River (0613M). It was also suggested that 'standing water' in
some cross-sections is contributed to run-off originating from grounds on either side. The surveyors have
further added that 'there is no water flowing through the reach'. Following an 'on-site' inspection by a RPS
senior engineer, it was suggested that the presence of a 'clay mound' blocked inflow from the main Fane
River (0613M) into this tributary (0613B). Based on this information it was suggested that 0613B be
omitted from 'Draft' model versions.
However, following a review of the 'Draft' model results; it was
revealed that the 1% and 0.1% AEP fluvial flooding scenarios are of a sufficient level to overtop this clay
mound. Following this observation, this reach (0613B) has been included the model Draft Final (Design)
versions of the Inniskeen Model.
Considering that the 'clay mound' is recognised as a hydraulically
significant structure it has been integrated into model simulations. It is represented in MIKE11 as part of a
weir (0613B chainage 69). Following an inspection of survey photographs and cross-sections it has been
assumed that weir levels (see left bank and marker 1) are at an elevation of 44.6mOD (Malinhead) to
represent this feature.
(b) A wall crosses the Lannat River at cross-section 0615M00044 (chainage 109.43) see Figure 4.2.28,
below. This wall has been included on the Draft Final model simulations. Based on the distance between
the cross-section 0613M00044 and 0613M00034 (1m) it has been estimated that the downstream invert
level is approximately 47.64mOD Malinhead.
IBE0700Rp0012
4.2-28
Rev F02
NWNB CFRAM Study
Figure 4.2.28: River Lannat, Cross-Section 0615M00044
(c) The culvert 0615M00026I, located on the River Lannat (between chainage 288.477m and 539.65m),
was modelled as six closed cross-sections with a constant diameter of 0.6m.
(d) An abandoned sluice gate located at cross-section 0613B00061 was not included in the model, since it
is no longer operational. This section of the river was treated as 'Open' rather than 'Closed Irregular’. As
evident from its current poor condition (see photograph 0613B000061_DN), it can be concluded that this
sluice gate is no longer operational.
(e) An assumption has been made regarding the downstream face and length of structure 0613D00001I.
At this point the culvert adjoins with the River Fane (0613M). Due to the presence of dense vegetation
coverage, the surveyors were unable to locate the downstream face of this culvert. Using the Draft model
network file, it was assumed that the downstream face of this structure is roughly similar to the surveyed
upstream face. It is also assumed that the downstream face of this structure is located at the end of this
reach, before it adjoins with the River Fane (chainage 61.34).
(f) 0614M00002D and 0614M00001I have been represented as one combined structure (0614M00001I) in
model simulations. Due to their close proximity (0.28m), the combination of these two structures improved
the stability of the model at this location.
(h) Both bridge and culvert structures were incorporated into the model as culverts. This approach was
applied following recommendations from DHI. This approach is justified in that DHI consider culverts to be
more stable. Furthermore there is no difference between defining the geometry of the culvert in the
Network Editor and using a cross-section file.
(i) An outlet channel was applied to the upstream extent of the River Fane, to allow the 0.1% AEP flood
extent to leave the 2D domain and prevent unrealistic water depths at the northern boundary. A constant
IBE0700Rp0012
4.2-29
Rev F02
NWNB CFRAM Study
water level of 59.19mOD Malinhead was applied to both the upstream and downstream cross sections of
the outlet reach. This constant water level is an initial 'dummy' value set only slightly greater than the bed
level of the cross section 0613M02208). This value is ignored once the flood extents reach the outlet,
which is connected to the 2D domain by a standard link. The level of the boundary varies in time based on
dynamic calculations driven by the flood extents.
(j) The downstream extent of the Fane River is tidally influenced.
Assessment
(2011s5232-Site
Assessment
-Inishkeen
It has been reported in a Site
see
http://nwnb.cfram.com/wp-
content/uploads/2011/10/2011s5232-Site-Assessment-Co-Louth_web.pdf)'
hat 'High' tide floods land
along the River Fane', see Section 4.2.5(5)(c). It has also been noted that the Fane River is tidal to
Stephenstown Bridge. Considering that the flooding associated with the downstream extent of this model
is tidally influenced, it is justified to apply a water-level boundary that reflects the dynamic nature of the
tidal cycle. The fluvial peak flow and peak TWL were adjusted so that they would occur simultaneously.
The generation of the water-level boundary applied to the Inniskeen model downstream extent is outlined
in Section 4.2.3(6).
(2) Hydraulic Model Limitations and Parameters:
Hydraulic Model Parameters:
MIKE 11
Timestep (seconds)
2
Wave Approximation
High Order Fully Dynamic
Delta
0.85
MIKE 21
Timestep (seconds)
2
Drying / Flooding / Wetting depths (metres)
0.02/0.03
Eddy Viscosity (and type)
0.025 Constant eddy formulation varying in space
2
based on equation k*x /t, where k=0.02
MIKE FLOOD
Link Exponential Smoothing Factor
0.8
(where non-default value used)
Lateral Length Depth Tolerance (m)
0.4
(where non-default value used)
(a) Sensitivity testing to be completed for final version.
(b) A model instability that was previously identified with structure (0613M01968D) during draft
(Calibration) modelling; has been resolved by adjusting the distance between relevant cross-sections e.g.
cross section at chainage 2423m was moved upstream to chainage 2427m. The 'spacing' of model crossIBE0700Rp0012
4.2-30
Rev F02
NWNB CFRAM Study
sections at structures is a standard procedure that promotes model stability.
(c) A model instability at the downstream extent of the Fane River, reflects the rising tide pushing against
fluvial flow. This model instability is prevalent at the downstream extent of the River Fane (chainage
2209m) but becomes significantly reduced further upstream (19371m). Although it has been stated that
the River Fane is tidal up to Stephenstown Bridge (18189.90m), the old 6 inch OS maps have been
annotated with 'Highest point to which Ordinary Tides flood', close to cross-section 0613M00260
(19548.8).
(d) Prior to Draft Final model runs, the MPW section of the Fane River (0613M) and Tributary 1 (0613A)
inaccurately represented the spatial extent of flooding. This 'glass-walling' is attributed to the limitations of
1D modelling. To resolve this issue, cross-sections located outside the 2d domain of the model
(downstream from chainage 5026.22m on the Fane River (0613M); and Fane Tributary 1 (0613A) were
extended in length beyond the River channel and across the Fane River flood-plain. The NDHM was used
to enable the extension of MPW cross-sections.
(e) A 5 x 5 m mesh was used in 2D modelling. It is considered that the 5 m resolution is best suited for
modelling purposes to maintain sufficient detail of the modelled area and floodplain. It is recognised that
some detail relating to Inniskeen may have been of too small resolution to be 'picked up' by LiDAR
information e.g. fences, walls, paths and minor roads. Therefore, it is recognised that complex hydraulic
processes of a finer resolution may not be represented in this model.
(3) Design Event Runs & Hydraulic Model Handover Notes:
(a) Upstream on the River Fane (0613M) (chainages -30 to 58); flooding occurs on the right bank (west)
during 10%, 1% and 0.1% AEP fluvial events. During the 1% and 0.1% AEP events, flooding occurs on
the right bank. Downstream at cross-section 0613M02163 (chainage 443.01m) flooding mainly occurs on
the left bank. The downstream route of flood flow is restricted by structure 0613M02144D; (see Section
4.2.3 (1) & Figure 4.2.10) and the remains of a railway embankment. Flood waters pond behind these
features in an area of agricultural land on the right bank of the river. No properties are at risk.
(b) There is flooding to the rear of a property located at the site of the former Moyles Mill (0613M02080
chainage 1303.27m) during 10%, 1% and 0.1% AEP fluvial events. During 10% AEP level, flooding splits
into two flow paths at 0613M02078 (1321.56m), merging again at 0613M02053 (1575.85m). Flood flow
routes follow the route of an abandoned mill race. The extent of flooding during 1% and 0.1% AEP fluvial
scenarios is restricted by the presence of a path located on the (west) left bank of the River between
0613M02058 (1537.75) to 0613M02038 (1722.24).
(c) The River Fane enters Inniskeen AFA after at cross section 0613M01978 (Chainage 2330m) and flows
beneath bridge structure 0613M01968D. During the 10% AEP fluvial flood event no significant flooding
occurs until its confluence with both the Inniskeen River (0614M) and Fane River Tributary 2 (0613B).
During the 10% AEP fluvial event, there is flooding downstream on the Inniskeen River (chainage 565m)
on the right bank (west). Directly downstream of this confluence, flooding occurs mainly on the left bank of
the River Fane (chainage 3164m to 3405m). After cross-section 0613M01888 (chainage 3238m) right
bank flooding is directed across the NNE boundary of St Daighs School playing fields and flows south east
over the pitch and putt park. Flooding occurs on both river banks around cross section 0613M01870
IBE0700Rp0012
4.2-31
Rev F02
NWNB CFRAM Study
(chainage 3405m).
These flood routes merge to join the main Fane channel near cross section
0613M01845 (chainage 3658m). At this point 'Gleneven house' is located in the path of flood flow route.
(d) During the 10% AEP fluvial event or greater, flooding occurs on both banks of the River Fane close to
cross section 0613M01973 (chainage 2364m). A Water Treatment Plant located here is at risk from
flooding.
(e) The rear of several properties located along St Daigh's Terrace, located downstream from
0613M1930D are at significant risk of flooding during the 10% AEP event. Furthermore Inniskeen Bridge
(0613M01906D) see Section 4.2.3(1) and Figure 4.2.11, restricts flood flow during 1% and 0.1% AEP
fluvial flood events. Several properties located upstream are at risk of flooding.
(f) The Lannat River is capable of containing flows within its banks for the 10% and 1% AEP fluvial events.
During the 0.1% AEP modelled event, 'out of bank' flooding is observed, which is due to the presence of
culvert 0615M00026I (chainage 288.5m to 540m). The model demonstrates that this structure cannot
efficiently convey large quantities of flood water. This leads to overland flooding in a downstream direction
(SSE) towards the River Fane.
(g) An inadequate sized culvert 0614M00053I (chainage 30m) located upstream along the Inniskeen River
significantly contributes to the flooding of an area, located on the right bank (west) of the River Inniskeen,
see Section 4.2.3(1) and Figure 4.2.9.
(h) Outside of the Inniskeen AFA, there is considerable flooding between cross section 0613M01659 and
0613M0519 for events of 10% AEP or greater. Several properties including residential and agricultural are
at risk from flooding.
(i) Upstream of Knockbridge (0613M01031D), flooding occurs on both sides of the River Fane.
Agricultural buildings situated on the right bank of the river (west) are at risk of flooding during 10% AEP
fluvial event or greater. The downstream extent of flooding is restricted by the presence of Knockbridge
and the R171.
(j) At the downstream extent of the River Fane (0613M) model, flood extents indicate that a section of the
M1 motorway is at risk from flooding during 10% AEP events or greater.
(4) Hydraulic Model Deliverables:
Please see Appendix A.4 for a list of all model files provided with this report.
(5) Quality Assurance:
Model Constructed by:
Tanya Ballentine & Jen Canavan
Model Reviewed by:
Stephen Patterson
Model Approved by:
Malcolm Brian
IBE0700Rp0012
4.2-32
Rev F02
NWNB CFRAM Study
APPENDIX A.1- MODELLED STRUCTURES
Structure Details – Bridges and Culverts
RIVER BRANCH
CHAINAG
E
INNISKEEN
29.592
INNISKEEN
391.784
INNISKEEN
531.241
FANE RIVER
660.698
FANE RIVER
984.473
FANE RIVER
1265.789
FANE RIVER
2425.9
FANE RIVER
2809.596
FANE RIVER
3044.519
IBE0700Rp0012
ID**
0614M00053I_Cul
vert
0614M00006J_Cul
vert
0614M00001I_Cul
vert
0613M02144D_Bri
dge
0613M02112D_Bri
dge
0613M02084D_Bri
dge
0613M01968D_Bri
dge
0613M01930D_cul
vert
0613M01906D_Bri
dge
LENGTH
(m)
OPENING
SHAPE
HEIGHT (m)
WIDTH
(m)
SPRING HEIGHT
FROM INVERT (m)
MANNING'S
n
5
1xCircular
50.42
0.9
N/A
0.015
197.736
1xArch
46.21
1.74
1.02
0.03
7
1xIrregular
44.83
1.63
N/A
0.021
9.4
1xArch
60.26
10.46
4.67
0.03
4.5
2xIrregular
55.08, 55.04
N/A
0.03
1.86, 2.03, 2.13
0.03
4.2
53.78, 53.77,
3xArch
53.77
4.42,
4.23
1.91,
2.25,
2.25
5.5
1xArch
55.15
11.53
9.17
0.021
3.7
1xIrregular
46.25
6.57
N/A
0.03
8
5xArch
46.04, 45.95,
3.54,
2.24, 2.13, 2.26, 2.28,
45.78, 45.81,
3.52,
2.03
4.2-33
0.03
Rev F02
NWNB CFRAM Study
RIVER BRANCH
CHAINAG
E
ID**
LENGTH
(m)
OPENING
SHAPE
HEIGHT (m)
WIDTH
(m)
45.71
3.83,
SPRING HEIGHT
FROM INVERT (m)
MANNING'S
n
N/A
0.03
N/A
0.035
2.2, 2.34, 2.07, 2.15
0.021
N/A
0.025
4.19
0.021
1.62, 3.8, 1.9
0.021
3.54,
3.87
FANE RIVER
FANE RIVER
3591.839
6227.329
0613M01851D_Bri
dge
0613M01588D_Bri
dge
5
3.8
3xIrregular
3xIrregular
42.21, 42.19,
42.19
31.91, 31.93,
31.94
4.03,
2.66,
2.82
2.93,
2.97,
2.88
2.48,
FANE RIVER
9004.076
0613M01311D_Bri
dge
7.7
4xArch
20, 19.85,
2.81,
19.71, 19.87
2.47,
2.49
3.17,
FANE RIVER
9814.853
0613M01230D_Bri
dge
7.5
4xArch
15.92, 16.04,
3.02,
16.03, 15.99
2.68,
3.15
FANE RIVER
FANE RIVER
IBE0700Rp0012
11808.96
0613M01031D_Bri
1
dge
15094.12
0613M00702D_Bri
1
dge
7.5
1xArch
13.17
9.5
3XArch
4.8, 4.89, 4.88
4.2-34
12.42
6.85, 7.3,
7.55
Rev F02
NWNB CFRAM Study
RIVER BRANCH
FANE RIVER
FANE RIVER
FANE RIVER
FANE RIVER
FANE RIVER
TRIBUTARY 1
FANE RIVER
TRIBUTARY 1
FANE RIVER
TRIBUTARY 1
FANE RIVER
TRIBUTARY 2
FANE RIVER
TRIBUTARY 3
FANE RIVER
TRIBUTARY 4
IBE0700Rp0012
CHAINAG
E
ID**
18197.41
0613M00392D_Bri
5
dge
18315.16
0613M00381D_Bri
4
dge
18452.86
0613M00367D_Bri
dge
21442.01
0613M00069D_Bri
1
dge
806.643
1034.087
1125.336
539.131
38.338
14.727
0613A00193D_Bri
dge
0613A00174D_Bri
dge
0613A00161D_Bri
dge
0613B00015I_Cul
vert
LENGTH
(m)
OPENING
SHAPE
HEIGHT (m)
WIDTH
(m)
SPRING HEIGHT
FROM INVERT (m)
MANNING'S
n
7.6
1xArch
4.37
11.08
3.492
0.018
34.5
1xIrregular
3.95
19.6
N/A
0.015
8.7
1xIrregular
4.84
14.09
N/A
0.021
26
2xArch
3.49.3.53
8.6, 8.6
2.7, 2.99
0.018
7.4
1xArch
3.01
1.73
1.73
0.021
79.3
1xArch
3.9
6.12
2.67
0.018
10.34
2XArch
6.48, 6.51
6.02, 5.6
5.21, 4.26
0.021
5.3
1XIrregular
41.01
2
N/A
0.021
7.4
1XIrregular
41.47
41.47
3
1xCircular
42.25
0.45
0613C00001D_Bri
dge
0613D00006I_Cul
vert
4.2-35
N/A
N/A
0.017
0.015
Rev F02
NWNB CFRAM Study
RIVER BRANCH
FANE RIVER
TRIBUTARY 4
FANE RIVER
TRIBUTARY 4
CHAINAG
E
ID**
LENGTH
(m)
OPENING
SHAPE
HEIGHT (m)
WIDTH
(m)
2.9
1xCircular
41.76
0.45
2
1XIrregular
41.6, 41.84
0.45
N/A
0.021
251.177
1xCircular
4.63
0.6
N/A
0.03
0613D00004I_Cul
33.314
vert
SPRING HEIGHT
FROM INVERT (m)
N/A
MANNING'S
n
0.015
0613D00001I_Cul
53.988
vert
0615M00026I_Cul
LANNAT
414.066
vert
Structure Details - Weirs:
RIVER BRANCH
FANE RIVER
CHAINAGE
856.717
ID
0613M02124W_Weir
MANNING'S N
TYPE
Broad Crested Weir
0613M01906D_Weir
0.035
0.035
FANE RIVER
3074.018
FANE RIVER
3135.344
0613M01896W_Weir
0.035
Broad Crested Weir
FANE RIVER
3210
0613M01890W_Weir
0.035
Broad Crested Weir
FANE RIVER
15001.822
0613M00712W_Weir
0.035
Broad Crested Weir
Broad Crested Weir
NB: All other weirs in the Network file are overtoppping weirs which form part of a composite structure
Structure ID Key:
D – Bridge Upstream Face
E – Bridge Downstream Face
I – Culvert Upstream Face
J –Culvert Downstream Face
IBE0700Rp0012
4.2-36
Rev F02
NWNB CFRAM Study
APPENDIX A.2
Long-profile showing the upstream MPW section of the River Fane (0.1% AEP fluvial flood event) see Section 4.2.3 & 4.2.6(3) for further details.
IBE0700Rp0012
4.2-37
Rev F02
NWNB CFRAM Study
Long-profile showing the River Lannat (0.1% AEP fluvial flood event) see Section 4.2.3 & 4.2.6(3) for further details.
IBE0700Rp0012
4.2-38
Rev F02
NWNB CFRAM Study
Long-profile showing the River Inniskeen (0.1% AEP fluvial flood event) see Section 4.2.9 & 4.2.6(3) for further details.
IBE0700Rp0012
4.2-39
Rev F02
NWNB CFRAM Study
Long-profile showing the River Fane and Tributary 2 (0613B) (0.1% AEP fluvial flood event) see Section 4.2.6(1) for further details.
IBE0700Rp0012
4.2-40
Rev F02
NWNB CFRAM Study
APPENDIX A.3
Peak Water
Flows
River Name & Chainage
INNISKEEN 529.453
06_997_3_RA
AEP
Check
Flow
(m3/s)
10%
1.87
1%
3.44
0.1%
6.1
LANNAT 463.5
10%
0.19
06_345_1_RARPS
1%
0.35
0.1%
0.61
FANE RIVER 3132.14
10%
23.95
06_92_1_RA
1%
33.43
0.1%
45.54
FANE RIVER 3932.72
10%
24.85
06_856_1_RA
1%
34.7
0.1%
47.26
FANE RIVER 5895.35
10%
25.28
06_856_5_RA
1%
35.29
0.1%
48.06
FANE RIVER 15740.1
10%
35.59
06035_RA
1%
49.68
0.1%
67.66
FANE RIVER 22072.2
10%
39.6
06_1093_D_RARPS
1%
55.69
0.1%
75.86
Model
Flow
(m3/s)
1.87
2.51
4.65
0.19
0.34
0.44
24.39
36.6
52.83
28.22
42.77
60.12
29.28
44.09
61.68
38.52
61.09
90.25
50
65
95.5
Diff (%)
-0.22
-26.95
-23.72
-1.05
-3.43
-27.92
+1.85
+9.49
+16.01
+13.57
+23.26
+28.34
+18.82
+24.94
+28.34
+8.24
+22.96
+33.38
+25.31
+16.72
+65.05
The table above provides details of the flow in the model at HEP intermediate / check points. These
flows have been compared with the hydrology flow estimation and a percentage difference provided to
ensure anchoring of the model to estimated flows.
Note that the estimation of flows at HEP check points and their reliability are discussed in the
hydrology report IBE0700Rp0008_UoM06 Hydrology Report_F02 under Sections 4 and 5.
HEP 06_997_3_RA (Ch. 529m) is located at the downstream extent of the Inniskeen River (0614M)
where it joins the River Fane (0613M). Model check flows are less than check flows at all three % AEP
design events. There is a difference of -0.22%, -26.95% and -23.72% for the 10%, 1% and 0.1% AEP
fluvial scenarios respectively. This is attributed to the occurrence of upstream flooding in an around
the Inniskeen Glebe, particularly the site of Lisarolagh Fort. Outputs from the 1% and 0.1% AEP
IBE0700Rp0012
4.2-41
NWNB CFRAM Study
design runs show the flow of flood waters into this area which is a relatively low-lying topographic
depression.
This flow attenuation is more accurately represented by hydraulic modelling than
hydrological estimation, so these differences during extreme design runs are reasonable.
HEP 06_345_1_RARPS (Ch. 463.5m) is at the downstream extent of the River Lannat, where it joins
the River Fane. There is a relatively small difference between estimated and model flows at the 10%
and 1% AEP levels, with a difference of -1.05% and -3.43%, respectively.
difference of -27.92% at the 0.1% AEP event.
However there is a
This is attributed to the presence of the culvert
(0615M00026I), see Section 4.2.3(1) and Figure 4.2.8. Simulation of the 0.1% AEP event shows that
the culvert restricts flow and out of bank flooding occurs resulting in a lower model flow downstream.
Intermediate HEP 06_92_1_RA on the River Fane (3132m) is located close to the Inniskeen River /
River Fane confluence. Model flow is higher than the hydrologically based estimates of flow at this
HEP illustrating a gain in model flow at this confluence which increases with flood event magnitude
(decreasing frequency). Model flow is 2%, 9.5% and 16% higher than estimated flow for the 10%, 1%
and 0.1% AEP events respectively.
The River Fane HEP 06_856_1_RA (chainage 3933m) is located near the downstream boundary of
the AFA. Model flow is higher than estimated flow with the difference increasing with flood event
magnitude, at 13.6%, 23% and 28% for the 10%, 1% and 0.1% AEP events, respectively. This HEP is
downstream from the point where the Millrace 0613B rejoins the River Fane (0613M). Gains in model
flow at the 1% & 0.1% AEP (>20%) are attributed to the flood waters greater than 10% AEP levels
'overtopping' the 'clay mound' located at the upstream end of (0613B) see Section 4.2.6(1)(a). This
Millrace (0613B) becomes active during a 1% and 0.1% AEP flooding event.
Intermediate HEP 06_856_5_RA is located along the MPW section of the River Fane (chainage
5895.35). Model flow is higher than estimated flow by 19%, 25% and 28% for the 10%, 1% and 0.1%
design events respectively.
This HEP is located approximately 300m upstream from structure
0613M01588D (Ch. 6227m, see Section 4.2.3(1), Figure 4.2.3(6)). The structure restricts flow causing
upstream build up which results in higher model flows at HEP node 06_856_5_RA, the effect of which
increases with event magnitude (decreasing frequency).
Intermediate HEP 06035_RA (Ch. 15740m) is located 200m upstream from Stephenstown Bridge
(0613M00702D) see 4.2.3(1) and Figure 4.2.13. Model flow is higher than estimated flow by 8%, 23%
and 33% for the 10%, 1% and 0.1% design events respectively. Again, this structure restricts flow
causing upstream build up which results in higher model flows at HEP node 06_856_5_RA, the effect
of which increases with event magnitude (decreasing frequency).
HEP 06_1093_D_RARPS is located at the downstream extent of the Inniskeen model and is subject to
tidal influence. A water level boundary was applied (see Section 4.2.3(6)) to reflect the tidal conditions
at this location. Discharge at this point in the model is a combination of fluvial and tidal components.
As a result, it is not possible to make a reliable comparison at this point as the hydrological estimates
only consider the fluvial component of flow.
IBE0700Rp0012
4.2-42
NWNB CFRAM Study
APPENDIX A.4 - DELIVERABLE MODEL AND GIS FILES
A list of all model files provided with this report
MIKE FLOOD
HA06_INIS5_MF_DES_12_Q10
MIKE 21
HA06_INIS5_M21_DES_15_Q10
MIKE 21 - DFS0 FILE
HA06_INIS5_DFS2_4_Road
Blocked_RR
HA06_INIS5_Corine
MIKE 21 RESULTS
I
MIKE 11 - SIM FILE & RESULTS
FILE
MIKE 11 - NETWORK FILE
HA06_INIS5_NWK_DES_15
MIKE 11 - CROSS-SECTION FILE
HA06_INIS5_XNS_DES_20
MIKE 11 - HD FILE & RESULTS
FILE
HA06_INIS5_HD_DES_15_Q10
MIKE 11 - DFS0 FILE
HA06_INIS5_DFSO_3_Q10
IBE0700Rp0012
MIKE 11 - BOUNDARY FILE
HA06_INIS5_BND_DES_5_Q10
4.2-43
Rev F02

Iniskeen - North West – Neagh Bann CFRAM Study

Transcription

Similar documents

here

Autumn 2014 - Fane Valley

Springfield Business Journal

AEP on the WEB

Sun Hydraulics` First Publication in pdf format

xtream - Carmor

What you have told us

Meteorologist: Jeremy Wheeler WAVY TV

LPRCA Factsheet - Long Point Region Conservation Authority