Comparison of the South Florida Water Management Model (SFWMM) with the
Simple Refuge Stage Model (SRSM) for the A.R.M. Loxahatchee National Wildlife Refuge
Michael G. Waldon [email protected]
William (Ben) Roth, Ehab A. Meselhe
Center for Louisiana Inland Water StudiesEcological Engineering Analysis & Modeling
University of Louisiana - Lafayette
ACKNOWLEDGMENTSThe South Florida Water Management District provided SFWMM files. Their cooperation & assistance are gratefully acknowledged.
Background – SFWMMSouth Florida Water Management Model
• Model domain is South Florida• 2x2 mile grid with other features• User specifies – rain, ETP• Calibration uses historic flows• Model outputs – stages, flows• Often applied in comparing alternatives• Regulatory flows calculated in predictive
mode
SFWMM –WCA-1
Source: SFWMD
Background – SRSMSimple Refuge Stage Model
• Model domain is WCA-1• Based on water budget• 2 compartments – Canal & Marsh• Constant surface area• Flow between canal & marsh calculated• Originally in Excel; Now Madonna• User specifies – rain, ETP, inflow, water supply• Model outputs – stage, regulatory outflow
SRSM Water Budget
Qin
P P
QMC
ET Qout GC ET
Canal Marsh
GM
Canal Stage = EC Marsh Stage = EM
AC = 1,000 acres AM = 139,000 acres
OBJECTIVES
• Set up SRSM run as similar as possible to a SFWMM simulation
• Compare model projections over the 36-year period of simulation
• Examine sensitivity of Refuge stage to inflow, outflow, & management assumptions using SRSM
SRSM IMPLEMENTATION
• SFWMD provided input & output files for SFWMM ECP Base model run
• Used historic rainfall & ET data• Inflow was from SFWMM• Outflows
– Regulatory release– Water supply
Outflow – Regulation Schedule
14
15
16
17
18
1-Jan
1-Feb
1-Mar
1-Apr
1-May
1-Jun
1-Jul
1-Aug
1-Sep
1-Oct
1-Nov
1-Dec
Stag
e (ft
)
MANDATORY (REGULATORY) RELEASE
WATER SUPPLY RELEASE
SFWMM S-10 CFS
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
-0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6
Canal - A1 Floor (ft)
CFS
Model Projections
14.0
14.5
15.0
15.5
16.0
16.5
17.0
17.5
18.0
18.5
Jan-65Jan-66Jan-67Jan-68Jan-69Jan-70Jan-71Jan-72Jan-73Jan-74Jan-75Jan-76Jan-77Jan-78Jan-79Jan-80Jan-81Jan-82Jan-83Jan-84Jan-85Jan-86Jan-87Jan-88Jan-89Jan-90Jan-91Jan-92Jan-93Jan-94Jan-95Jan-96Jan-97Jan-98Jan-99Jan-00Jan-01
Mar
sh s
tage
(ft)
SRSM SFWMM
Historic S-10 CFS
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
-2.5 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5
Canal - A1 Floor (ft)
CFS
SFWMM & Historic Water Supply(thousand acre-ft/year)
0
20
40
60
80
100
120
140
160
180
200
1965196619671968196919701971197219731974197519761977197819791980198119821983198419851986198719881989199019911992199319941995199619971998199920002001200220032004200520062007
ECPBASE Historic
Average days per yearmeeting condition
Above Above Below BelowSource HistRR HistWS 17 ft 17.5 ft 16 ft 15.5 ftSFWMM 110 44 89 15SRSM 101 32 90 7SRSM X 84 27 106 13SRSM X 98 31 100 20SRSM X X 81 26 117 25
Observed 58 10 50 0.2
0
20
40
60
80
100
120
140
160
180
0.5 0.75 1 1.25 1.5 1.75 2
Inflow Multiplier
Day
s pe
r yea
r
<15.5 <16 >17 >17.5
SRSM – Sensitivity to Inflow
Conclusions: Findings relevant to Everglades restoration
• Marsh stage sensitive to water supply demands• Marsh stage sensitive to regulatory releases• Simplified modeling is efficient, & is one of multiple
tools used to evaluate impacts of alternatives• There is value in having multiple models based on
different assumptions & levels of complexity• Comparison of alternative models
– increases credibility– identifies model limitations– identifies areas needing investigation & improvement
Questions?