This document describes the SLOSH Basin Definition File (dta-file) format,
structure, and configuration options.
ABOUT
The SLOSH basin definition file (???dta or ????dta) contains the bathymetry,
topography, and sub-grid routing features for a specific computational area.
There have been three major versions of the dta-file:
- v1: 199201
- v2: 201408 (Added version and horizontal projection info before Line 1)
- v3: 201903 (Introduced the Manning-n friction section)
File Properties
- Format: Unix format (LF line endings).
- Permissions:
664 - Locations:
/parm/dta: Active high-resolution basins./parm/dta/etss: Active coarse-resolution extra-tropical basins./parm/dta_m: Inactive Manning-n basins./parm/dta_o: Inactive original basins (replaced in March 2023).
STRUCTURE & SECTIONS
A standard dta-file is composed of 12 sequential sections. Note that newer
versions (v2, v3) utilize expanded indexing (4-digit vs 3-digit) and deeper
depth definitions (5-digit vs 4-digit) to accommodate higher-resolution data.
Elevations above sea level are stored as negative depths (e.g., Challenger Deep
is 36200, Mount Everest is -29029).
- Header: Contains “Line 1” configuration, grid definitions, and time-steps.
- Barriers: Uses 4-digit indexes in v2/v3.
- 1-D Flow Points: Uses 4-digit indexes in v2/v3.
- 1-D Flow with Banks: Uses 4-digit indexes in v2/v3.
- Raised Weirs: Deprecated.
- Channels: Deprecated.
- Cuts / Chokes: Uses 4-digit indexes in v2/v3.
- Trees: Defines areas with high friction canopies.
- Manning-n: Added in v3 for variable bottom friction.
- Printed Panels: Deprecated.
- Depths: Uses 5-digit depths in v2/v3.
- Levee Points: Defines cells inside levee systems that must not be initialized as “wet.”
LINE 1 CONFIGURATION OPTIONS
The first operational line of the header (“Line 1”) dictates the global physics, boundaries, and smoothing rules for the basin. It relies on strict column positioning:
| Columns | Description | Values / Flags |
|---|---|---|
| 1–11 | Basin Name | Standard string identifying the basin. |
| 12 | Grid Type | ' ' = Polar, '$' = Elliptical, '+' = Hyperbolic |
| 13–14 | Boundary | '$ ' = Closed island (periodic boundary condition) |
'2$' = MSY basin, '1$' = Initialize dry cells |
||
| 15 | Smoothing | '+' = every time-step, '=' = also call smpt2g |
'#' = every 5 time-steps, '!' = also call smpt2g |
||
'%' = every 10 time-steps, '@' = also call smpt2g |
||
'&' = every 20 time-steps |
||
'*' = every 30 time-steps, '^' = also call smpt2g |
||
| 16 | Output Order | ' ' = Default (I-J), '+' = Reversed (J-I) |
| 17 | Special | '&' = Southern Hemisphere, '$' = Okeechobee (XOKE = 'X') |
| 18 | Over-Top | '+' = Disallow over-topping of barriers |
| 19 | 1D Flow | '+' = Disallow 1D flow routing |
| 20 | High Terrain | '+' = Allow flooding between 35 and 56 feet |
| 21 | X-Filter | Standard Method: |
'+' (HCRT=0.5), '$' (HCRT=0.4), '#' (HCRT=0.3), '@' (HCRT=0.2), '-' (HCRT=0.1) |
||
| Exclude cells by Epsilon Method: | ||
'=' (HCRT=0.5), '&' (HCRT=0.4), '^' (HCRT=0.3), '%' (HCRT=0.2), '*' (HCRT=0.1) |
||
| 45–51 | Revision Tag | Reserved for the string REVISED. |
| 54–63 | Revision Date | Timestamp of when the basin was last updated. |
