CMS-Flow Tide Gates

UNDER CONSTRUCTION

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.

• Implementation of Structures in the CMS: Part IV, Tide Gate

Future SMS versions (13.4.x)

SMS 13.4 CMS-Flow model coverages.

A "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.
• The "Structures" coverage will need to be applied to the CMS Simulation in order to export the appropriate cards to the parameter file.

Values needed by the CMS for each Tide Gate are listed in the table below. If there is a user-definable option in the dialog for the user to enter a value, the word 'Dialog' is shown in column 2, otherwise the words 'No dialog' are written in column 2.

List of tide gate structure parameters

Number of Cells	No dialog
Cell IDs	No dialog
Distribution Coefficient	Dialog
Orientation of Tide Gate	Dialog
Type of Weir	Dialog
Flow Coefficient Bay to Sea	Dialog
Flow Coefficient Sea to Bay	Dialog
Gate Opening Height	Dialog
Bottom Elevation of Tide Gate	Dialog
Calculation Method	Dialog

SMS will handle the assignment of the appropriate values for Number of Cells and Cell IDs.

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 being tested with CMS 5.3.12 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	Indent 2 spaces?	Type of value written	Dependent on	Notes
TIDE_GATE_STRUCT_BEGIN	NO	N/A
CELL_IDS	YES	<int> <multiple int>		Total number of cells (n) followed by a list of all cell ids (from 1 to n).
DISTRIBUTION_COEFF	YES	<real>
ORIENTATION	YES	1, 2, 3, or 4		Direction of Sea side: 1= North, 2= East, 3= South, 4= West
TYPE	YES	1 or 2		1= Sharp-crested, 2=Broad-crested
FLOW_COEFF_FROM_BAY	YES	<real>
FLOW_COEFF_FROM_SEA	YES	<real>
OPENING_HEIGHT	YES	<real>		How large the opening for the gate is.
BOTTOM_ELEVATION	YES	<real>		Positive is upward
METHOD	YES	1 or 2		1= Approach 1, 2= Approach 2 (see literature)
SCHED_OPERATION_TYPE	YES	'REG', 'DES', 'EBB', 'UCG'		'REG' - regular time interval 'DES' - designated time periods 'EBB' - open gate for ebb tide, close for flood 'UCG' - uncontrolled gate
REG_START_TIME	YES	<int>	Operation type == 'REG'	Start time (hour)
REG_OPEN_FREQUENCY	YES	<int>	Operation type == 'REG'	Opening frequency (hour)
REG_OPEN_DURATION	YES	<int>	Operation type == 'REG'	Open duration (hour)
NUM_DESIGNATED_TIMES	YES	<int>
DES_START_TIME	YES	<int>	Repeated for number of designated times	Start time (hour)
DES_OPEN_DURATION	YES	<int>	Repeated for number of designated times	Open duration (hour)
TIDE_GATE_STRUCT_END	NO

An example tide gate block is shown below:

Last update 9/25/2024
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