A Blockage models a time-varying obstruction with user-defined contraction and expansion loss coefficients. The blockage is assumed to be vertical; in other words, the same proportion of the flow area is obstructed whatever the water level.
The following table describes all the blockage specific data which can be used to define a blockage in a channel, conduit or river reach. For details of results fields, see the Link Results Data Fields topic.
Fields that are common to the majority of objects can be found in the Common Fields topic.
Blockage Data
Database Table Name: hw_blockage
|
Field Name |
Description |
Database Field |
Size |
Precision |
Default |
Error Lower Limit |
Error Upper Limit |
Warning Lower Limit |
Warning Upper Limit |
||
|---|---|---|---|---|---|---|---|---|---|---|---|
| US node ID |
Identity of the upstream node for this blockage. |
us_node_id | Text | 64 | 0 | ||||||
| DS node ID | Identity of the downstream node for this blockage. | ds_node_id | Text | 64 | 0 | ||||||
| Link suffix |
Link suffix of the conduit, channel or river reach with which this blockage is associated. |
link_suffix | Text | 1 | 0 | ||||||
| Link type | The type of link. Default is BLKAGE (blockage). | link_type | Text | 6 | 0 | BLKAGE | |||||
|
Asset ID |
For reference only. Designed as a reference to an asset database, but could be used for anything. |
asset_id |
Text |
64 |
|
0 |
|
0 |
|
|
|
|
Sewer reference |
An optional reference to identify the sewer to which an associated conduit is a part. |
sewer_reference |
Text |
80 |
|
0 |
|
|
|
|
|
| Length | The length between the US node ID and the DS node ID is automatically calculated when both fields have been specified. | ||||||||||
|
System type |
The system type can be selected from the dropdown. |
system_type |
Text |
10 |
|
0 |
Other |
|
|
|
|
|
Branch ID |
Used to identify to which long section the link is associated. Can be set manually or automatically (see Defining Branches topic for more information). |
branch_id |
Long Integer |
|
|
0 |
|
0 |
|
|
|
|
US settlement efficiency (%) |
Relevant to Water Quality Simulations only.
|
us_settlement_eff |
Long Integer |
|
|
0 |
0 |
0 |
100 |
|
|
|
DS settlement efficiency (%) |
Relevant to Water Quality Simulations only.
See the description of US Settlement Efficiency. |
ds_settlement_eff |
Long Integer |
|
|
0 |
0 |
0 |
100 |
|
|
| Blockage type |
The type of blockage can be set to:
See the Blockage topic for further information. |
blockage_type | Text | Local | |||||||
| Initial blockage | The initial blockage proportion can be set to between 0.0 (no blockage - free flow) and 1.0 (fully blocked - no flow). | blockage_proportion | Double | 3 | 0 | 0 | 1 | ||||
| Inlet loss coefficient | The inlet loss coefficient must be greater or equal to 0.0. | Inlet_loss_coefficient | Double | 3 | 1.5 | 0 | |||||
| Outlet loss coefficient | The outlet loss coefficient greater or equal to 0.0. | Outlet_loss_coefficient | Double | 3 | 1.0 | 0 | |||||
| Positive blocking rate |
The rate at which the proportion of the blockage goes from one state to another in a positive direction. The value must be greater than zero. |
positive_prop_change | Double | RS | 5 | 0.1 | 0.000001 | ||||
| Negative blocking rate |
The rate at which the proportion of the blockage goes from one state to another in a negative direction. The value must be greater than zero. |
negative_prop_change | Double | RS | 5 | 0.1 | 0.000001 | ||||
|
Threshold |
The minimum blockage proportion step which the software will implement. Any changes below this threshold will be ignored. This prevents oscillation. |
threshold |
Double |
|
|
5 |
0 |
0 |
|
|
|
|
InfoAsset unique ID |
Unique ID associated with the corresponding object in an InfoAsset Manager database. When importing from InfoAsset Manager, the InfoAsset ID can be copied from the InfoAsset database in order to maintain links between the two networks. |
asset_uid |
GUID |
|
|
0 |
|
0 |
0 |
0 |
0 |