South Florida Salinity and Hydrology Models

South Florida Hydrology and Salinity Models

·     Evaluation of hydrology and salinity models for Everglades

·     Each model scored according to accepted model performance criteria

·     Complex numeric models were least portable and hardest to use, though they supply much greater detail

·     Empirical models were easiest to use and less-expensive to run with less detail in the output

ABSTRACT

This study evaluated the hydrology and salinity models being used for Everglades restoration. Each model that was reviewed was assigned a series of scores for achieving the modeling criteria, with 5 being the highest score (excellent).  The widest ranges of scores were for portability and ease-of-use reflecting the constraints of model sophistication.  The narrowest range of scores was associated with validity – most of these models have withstood the test of use and have been developed, reviewed, and updated to a point of application-ready acceptance. 

In general, the most complex models (SWMM, RSM, FTLOADDS, EFDC Florida Bay, Wang et al. (2003) Biscayne Bay, TABS MDS Biscayne Bay) are the least portable, are rated lowest for ease of use, and did not score as high on validity as did the models that are less complex (linear regression models for stage and flow, MLR salinity models, FATHOM, Four Box Model Florida Bay, Biscayne Bay Box Model). 

Temporal coverage was best for the regression models because they are daily time step models and can be run for the longest periods of time.  For spatial coverage, none of the models covers the full domain of the south Florida coastal system but most model domains cover the region(s) of focus. 

The least expensive models to employ are the least sophisticated statistical models and box models.  The use of grid-domain freshwater models covering a large region such as the spatial domain of the SFWMM and RSM will always require more budget than the freshwater ecosystem statistical and box models by a substantial amount.  However, there are important transport, exchange, and circulation questions in the connected Everglades freshwater and estuarine system that requires a very high level of resolution, justifying the use of more sophisticated models. 


Table ES-1: Summary of General Information on Hydrology and Salinity Models Currently in Use in South Florida.

Model Name

Model Type

Simulated Parameters

Spatial Domain

Grid Size

Simulation temporal domain

Relevant Time Step

Linear Regression Models

Statistical

Stage, Flow

Everglades

N/A

1965-2000

daily

PHAST

Wetland Basin

Flow

Everglades and Mangrove Zone

regional

1965-2000

monthly

SFWMM

Freshwater Hydrology

Stage, Flow

Everglades

3.2km X 3.2km

1965-2000

daily

RSM

Freshwater Hydrology

Stage, Flow

Everglades

variable

1965-2000

daily

ENPMod1

Freshwater Hydrology

Stage, Flow

Everglades

3.2km X 3.2km

1965-2000

daily

MLR

Statistical

Salinity

FL Bay, WW Bay, SW Gulf coast, Manatee Bay, Barnes Sound

N/A

1965-2000

daily

Four Box Florida Bay

Mass Balance

Salinity

Florida Bay

regional

1993-1998

monthly

Biscayne Bay Box Model

Mass Balance

Salinity, nutrients

Biscayne Bay

box, variable

1993-2007

monthly

FATHOM

Mass Balance

Salinity, nutrients

Florida Bay, Manatee Bay, Barnes Sound

open-water basins

1970-2000

monthly

FTLOADDS TIME/TTI

2D/3D Coupled surface and groundwater

Stage, Flow, Salinity

Everglades, northern Florida Bay, SW Gulf coast, TTI

0.5km X 0.5km

daily

EFDC

3-D Hydrodynamic

Salinity

Florida Bay

variable

1997-2000

daily

Wang et al., 2003 Biscayne Bay

3-D Hydrodynamic

Salinity

Biscayne Bay

variable

1995-1999

daily

TABS MDS Biscayne Bay

3-D Hydrodynamic

Salinity

Biscayne Bay

variable

daily

 

Table ES-2: Summary of scoring for south Florida hydrology and salinity models using the model evaluation criteria. Score is from 1 = lowest to 5 = highest.  No scores are provided for the category of model focus because all of the models satisfy the requirement that the output be relevant to ecosystem attributes. 
 

Model

Parameters simulated

Portability

Validity

Fidelity

Focus

Ease of Use

Temporal Coverage

Spatial Coverage

Linear regression models for stage

stage

3

4

2

-

5

5

3

PHAST

flow

2

4

2

-

5

4

2

SFWMM

stage, flow

3

4

4

-

4

4

4

RSM

stage, flow

1

5

4

-

1

5

4

MLR

salinity

5

5

2

-

5

5

3

Four Box Florida Bay

salinity

2

5

3

-

4

4

3

Biscayne Bay Box Model

salinity

3

5

3

-

4

4

3

FATHOM Florida Bay

salinity

4

5

4

-

4

4

3

FTLOADDS TIME / BISECT / TTI

stage, flow, salinity

3

4

5

-

3

3

4

EFDC Florida Bay

salinity

1

4

5

-

2

2.5

3

Wang et al., (2003) Biscayne Bay

salinity

3

4

4

-

3

2.5

3

TABS MDS Biscayne Bay

salinity

1

4

5

-

1

2.5

3

 


 


 

 

 

 


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