TUFLOW Urban Flood Models. Introduction. TUFLOW UK 2011 User Group Workshops. Phillip Ryan, Modelling Pipe Networks

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1 TUFLOW 2011 Modelling Pipe Networks Urban Flood Models 2 Introduction TUFLOW Pipe Networks Culverts Pits (Drains) Manholes / Junctions Linking to ISIS Tips and Tricks 3 1

2 Pipe Network Elements Lines or Polylines Culverts / Pipes Points Nodes Pits (Drains / Gully Traps) Manholes 4 Culverts (Pipes) Convey the water underground Very short pipes (several metres) Force 1D timestep down Source of 1D instabilities Very long pipes (hundreds of metres) Poor hydraulic grade line 5 Culverts (Pipes) cont... Lines or Polylines Connectivity based on snapping Use consistent direction (upstream to downstream) 6 2

3 Culvert Types Circular (Pipes) Rectangular Irregular (any shape) 7 Pits (Drains / Gully Traps) Convey the water between above ground and below ground Input as points Converted to a channel (zero length) Displayed as short vertical lines (Can change using Pit Channel Offset == ; Default = 10m) 8 Pit Connectivity (as of Build AB) Any number of pits can be snapped or connected to a digitised node or manhole Pit Search Distance == [ {0.0} <dist> ].ecf command that sets the search distance for automatically connecting pits/drains to the nearest 1D node pits do not need to be snapped to a 1D node or pipe end very useful where the location of the pits is known, but the connecting pipe to the main trunk line is not known Pit Default 2D Connection == [ {} <Conn_2D> ] sets the default 1d_nwk Conn_2D value for example, if set to SX, then if the 1d_nwk Conn_2D attribute for a pit is empty, SX is used to disconnect a pit NO can be used for the Conn_2D attribute now possible to have the L and Z options at the one pit (eg. SXLZ) (previously only a maximum of three characters was allowed) 9 3

4 Pit Types Zero Length Culvert R Rectangular W Weir C Circular (rarely used) Section in the vertical plane Q Type Depth Discharge Curve from a Database Requires knowledge of pit design 10 R Pits Usually shallow wide shape For example, 0.15m high x 1.2m wide Uses R culvert routines Zero length so Manning s n not relevant 11 W Pits Width set to approximate weir flow width Mainly used where it is assumed that the pit is not a control (ie. water freely enters pipe system) OK representation if overland flow is shallow Possibly poor representation if overland flow is deep 12 4

5 Q Pits Preferred option Need to know or assume Pit Type/Design Depth Discharge (y-q) curve Setup a database of y-q curves (similar to BC Database) 13 Pit Database See Section of 2010 Manual 14 Manholes Represent pipe junctions Simulate energy losses at junctions Must have at least one pipe in and one pipe out 15 5

6 Manhole Input Use 1d_mh layer for specifying individual manholes (can t use 1d_nwk layer) Manholes at all Junctions == ON assigns a manhole to every closed node (pipes only) (manholes in 1d_mh layer(s) will override the automatic ones) Manhole Default Loss Approach == [ NONE FIXED {ENGELHUND} ] sets default loss approach If a manually digitised manhole occurs more than once within all of the 1d_mh layer(s), the last one prevails (can override for what-if scenarios) 16 Manhole Types Left blank uses default setting (see previous slide) NO No manhole (treated as a Node) FX Fixed (User Specified) Losses EN Engelhund Approach to Losses Others can be incorporated 17 Junction Energy Losses Node or NO Manhole Structure Losses == ADJUST (the default) or Channel A Flag Inlet/Outlet Losses of pipes/manholes are adjusted based on approach/departure velocities (see Section of the 2010 Manual) Adjusted down to zero if velocity unchanged through node Structure Losses == FIX or Channel F Flag Full pipe inlet/outlet losses are applied Can significantly overestimate losses 18 6

7 Junction Energy Losses FX and EN Manholes For FX and EN Manholes Exit loss coefficients of all inlet pipes ignored Entrance loss coefficients of all outlet pipes ignored Manhole approach applied instead Any pipe Form_Loss (bend loss) values are applied 19 Junction Energy Losses FX Manhole K_Fixed attribute sets total losses for manhole (default = 0.0, ie. no losses) Proportion/Multiplier of outlet pipe velocity head Can exceed 1 User specified based on literature guidelines 20 Junction Energy Losses EN Manhole Based on following loss coefficients K in expansion from water flowing into manhole K Ɵ losses due to approach-departure angles of pipes K drop drop losses due to change in pipe inverts K out contraction losses into outlet pipe(s) K f Any user specified additional fixed losses Loss coefficients recalculated every timestep Equations in manual 21 7

8 Junction Energy Losses EN Manhole (cont...) User can specify (in most cases simply use defaults) Width of manhole (the flow width) (default not yet finalised) K m Inlet loss coefficient of outlet pipe(s) (default = 0.5) K f Optional (default = 0) 22 Junction Energy Losses EN Manhole (cont...) Angle of approach for inlet pipes based on last segment of polyline For outlet pipes the first segment Whether inlet or outlet pipe based on flow direction (not digitised direction) 23 Linking to ISIS ISIS-TUFLOW-PIPE ISIS and TUFLOW 1D (ESTRY) domains can now be dynamically linked Need ISIS-TUFLOW-PIPE from Halcrow Software Free upgrade for existing ISIS-TUFLOW licencees Allows TUFLOW pipe networks to connect to ISIS river units Can connect any TUFLOW 1D node to ISIS unit 24 8

9 Linking to ISIS Linking Logic ISIS and ESTRY nodes will be considered as linked if: An ESTRY node in a 1d_nwk layer, and an ISIS node in a "Read GIS ISIS Nodes ==" or "Read GIS ISIS Network ==" layer are snapped The ESTRY node has a Conn_2D attribute (which has been renamed for empty layers as Conn_1D_2D) of either "X1DH" or "X1DQ" (explained next slide) If Conn_1D_2D is blank X1DH is assumed Can use a connector "X" channel to connect the end of an ESTRY channel or node to the ISIS node if not in the same location The upstream and downstream inverts for the ESTRY node linked to ISIS should be set to unless the node invert is used to set the inverts of the channel(s) snapped to it 25 Linking to ISIS Link Types X1DH link an ISIS 1D water level is applied at the ESTRY node ie. ISIS sends ESTRY a water level and ESTRY sends back an in/outflow to ISIS X1DQ link an ISIS in/outflow is applied at the ESTRY node ie. ISIS sends ESTRY an in/outflow and ESTRY sends back a water level For most ISIS-ESTRY links an ESTRY X1DH (the default) would be used X1DQ applicable where an ISIS domain terminates and flows into an ESTRY domain 26 Linking to ISIS Other Notes The mass balance _MB1D.csv file includes four new columns: X1DH V In: The volume of water in via a X1DH link X1DH V Out: The volume of water out via a X1DH link X1DQ V Out: The volume of water out via a X1DQ link X1DQ V In: The volume of water in via a X1DQ link The type or existence of a connection can be checked by viewing the Conn_1D_2D attribute in the 1d_nwk_N_check layer The _messages.mif layer contains CHECK 1393 messages at each ESTRY node linked to an ISIS node 27 9

10 Pipe Network Tips Converting GIS to 1d_nwk Keep backward traceability Append some/all GIS attributes to 1d_nwk attributes Data Integrity (Snapping!) Use 1d_nwk_N_check (Nodes colour coded based on snapped channels) 28 Stability Tips 1D timestep for pipe models usually in range from 0.1s to 1.0s Beware of very short/steep pipes Sometimes additional storage added Manually via 1d_nwk ANA attribute Minimum Channel Storage Length == (Default is 0) Storage Above Structure Obvert (%) == (Default is 5%) 29 Modifying Networks Can upgrade or modify existing pipes or manholes by overriding in subsequent layers Select and save pipes/manholes to be modified Save as new 1d_nwk/1d_mh layer Modify pipes/manholes Add in new Read GIS Network / Read GIS Manholes line after original layer Cross-check using check layers and/or viewing.eof file 30 10

11 Viewing Results GIS Output Layers _TS.mif Charting Times-Series Data using mitools _TSF.mif Flow Regime Flags over time _TSL.mif Inlet/Bend/Outlet Losses over time _mmx.mif layers for viewing peak h, V and Q values _cca.mif layer for viewing pipe performance _TSMB.mif layers for identifying unhealthy points 31 Viewing Results (cont...) Animate/Map using WLLs Use WLL Automatic == CULVERTS to automatically generate WLLs.csv files for viewing/charting time-series in Excel New excel utilities on the website.eof file for text viewing all input and output data 32 Detailed Urban Models

12 Detailed Urban Models 1,600 pipes / culverts 900 pits (drains) 600 manholes 1.8 million wet cells at peak 0% Mass Error 34 12