CMS-Flow Tide Gates
Introduction
A tide gate is an opening structure built across a river or a channel in an estuarine system. By preventing saltwater intrusion to farm land and allowing freshwater drainage to the estuary, tide gates are commonly used for flow and flooding control, and salinity and sediment management. Because a tide gate is a significant component of hydrodynamic and sediment transport controls in the coastal zone, it is important to incorporate the structure and to simulate its effect in the CMS.
Usage of Tide Gages for CMS in the SMS
Early SMS versions (< 13.4)
Previous documentation (Link given below) described the formulation and implementation of Tide Gates in CMS, detailing input requirements for SMS versions up to 11.2. This implementation required hand-manipulation of the CMS-Flow parameter files to add in lists of cells and option values.
Future SMS versions (13.4.x)
A CMS-Flow structures coverage has been added beneath the CMS-Flow model option in SMS 13.4 and later. This one coverage will handle Tide Gates as well as three other types: Rubble Mounds, Weirs, and Culverts.
Tide Gates are added to this coverage with the placement of Feature Arcs.
- Simply create a new feature arc within the new CMS-Flow structures coverage.
- Select the arc and double click the arc to open the dialog.
- Choose "Tide Gate" for the type and then enter the needed information on the right side of the dialog.
- When finished, the CMS-Flow structure coverage will need to be applied to the CMS Simulation in order to export the appropriate cards to the parameter file.
SMS will handle the assignment of the appropriate values for Number of Cells and Cell IDs. See the table below for any dependencies for the above parameters.
CMS-Flow specific information
The parameters/selections for each Tide Gate feature arc will be exported to the ‘.cmcards’ file in the form of a block of values.
This implementation is available with CMS 5.4.0 and later.
- The Tide gate parameter cards needed for each gate are added to a structure block with a corresponding BEGIN/END statement for each gate are listed in the table below.
- For readability and to be consistent with other cards in the .cmcards file, all values should start in column 36 and 3 spaces written between each value per line if more than one.
| Cardname | Type of value written | Dependent on | Notes |
|---|---|---|---|
| TIDEGATE_STRUCT_BEGIN | N/A | ||
| CELL_IDS | <int> <multiple int> | Total number of cells (n) followed by a
list of all cell ids (from 1 to n). | |
| DISTRIBUTION_COEFFICIENT | <real> | ||
| ORIENTATION_SEA | 'NORTH', 'SOUTH', 'EAST', 'WEST' | Direction of Sea side | |
| FLOW_COEFF_FROM_BAY | <real> | ||
| FLOW_COEFF_FROM_SEA | <real> | ||
| OPENING_HEIGHT | <real> | How large the opening for the gate is. | |
| BOTTOM_ELEVATION | <real> | Positive is upward | |
| METHOD | 1 or 2 | 1= Approach 1, 2= Approach 2 (see literature) | |
| SCHED_OPERATION_TYPE | 'REG', 'DES', 'EBB', 'UCG' |
'REG' - regular time interval 'DES' - designated times and durations 'EBB' - open gate for ebb tide, close for flood 'UCG' - uncontrolled gate | |
| REG_START_TIME | <int> | Operation type == 'REG' | Start time (hour) |
| REG_OPEN_FREQUENCY | <int> | Operation type == 'REG' | Opening frequency (hour) |
| REG_OPEN_DURATION | <int> | Operation type == 'REG' | Open duration (hour) |
| NUM_DESIGNATED_TIMES | <int> | Operation type == 'DES' | |
| DES_START_TIME | multiple <int> | Operation type == 'DES' | Start time (hour) Repeated for number of designated times |
| DES_OPEN_DURATION | multiple <int> | Operation type == 'DES' | Open duration (hour) Repeated for number of designated times |
| TIDEGATE_STRUCT_END |
An example configuration for two tide gates is shown below:
TIDEGATE_STRUCT_BEGIN CELL_IDS 3 20 50 70 DISTRIBUTION_COEFFICIENT 0.9 ORIENTATION_SEA NORTH !NORTH, EAST, SOUTH, WEST FLOW_COEFF_FROM_BAY 0.5 FLOW_COEFF_FROM_SEA 0.46 OPEN_HEIGHT 2.0 BOTTOM_ELEVATION -1.0 METHOD 1 !1= Approach 1, 2= Approach 2 SCHED_OPERATION_TYPE REG !REG, DES, EBB, or UCG REG_START_TIME 0 !-- This is elapsed hours from start (immediately on first day) REG_OPEN_FREQUENCY 18 !-- Reopen every 18 hours after the initial opening REG_OPEN_DURATION 6 !-- Keep gate open for 6 hours each time. TIDEGATE_STRUCT_END TIDEGATE_STRUCT_BEGIN CELL_IDS 2 600 620 DISTRIBUTION_COEFFICIENT 0.8 ORIENTATION_SEA NORTH !NORTH, EAST, SOUTH, WEST FLOW_COEFF_FROM_BAY 0.45 FLOW_COEFF_FROM_SEA 0.4 OPEN_HEIGHT 1.5 BOTTOM_ELEVATION -1.5 METHOD 1 !1= Approach 1, 2= Approach 2 SCHED_OPERATION_TYPE DES !REG, DES, EBB, or UCG NUM_DESIGNATED_TIMES 3 DES_START_TIME 15 35 56 !-- Open gate at 15, 35, and 56 hours after start of run DES_OPEN_DURATION 6 7 6 !-- Keep gate open for 6, 7, and 6 hours, respectively. TIDEGATE_STRUCT_END
Example Case
One example case for Tide Gates is described below and example files are provided in the next section. This example introduces an idealized grid with a smaller bay area and medium sized off-shore area. A segment through the inlet is designated as a tide gate structure which has the following regular (recurring) schedule:
- First open time - 0.00 hours (immediately at start of simulation).
- Open duration - for 12 hours after each open.
- Open frequency - every 24 hours.
The grid and bathymetry is shown in the figure to the right with the tide gate structure identified by the feature arc in the inlet.
Input and output files
Below are the prospective project and input/output files for SMS 13.4/CMS 5.4.0 which show the REGULAR tide gate schedule:
Last update 12/19/2024
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