Myakka River Watershed Initiative Myakka River Watershed Initiative Status Briefing and Next Steps Status Briefing and Next Steps September 12, 2008 September 12, 2008
Status Myakka River Watershed Initiative Status Myakka River Watershed Initiative � Project Recap and Background Project Recap and Background � � Water Budget Modeling Water Budget Modeling � � Floodplain Modeling Floodplain Modeling � � Where we go from here Where we go from here � 2 2
Background Background � Classie Farms and Pacific Tomato projects developed in Classie Farms and Pacific Tomato projects developed in � response to study findings response to study findings � Environmental concerns continue in the Upper watershed Environmental concerns continue in the Upper watershed � � MFL indicates MFL indicates “ “excess excess” ” water present in the Upper water present in the Upper � Myakka River Myakka River � Staff requests funding to initiate watershed wide study Staff requests funding to initiate watershed wide study � (comprehensive watershed management) on the Myakka (comprehensive watershed management) on the Myakka River to address alterations and work toward desired River to address alterations and work toward desired watershed condition watershed condition � Singhofen & Associates team awarded MRWI contract. Singhofen & Associates team awarded MRWI contract. � � NTP December 2006 NTP December 2006 � 3 3
Project Objectives Project Objectives � Evaluate and illustrate the effects of past Evaluate and illustrate the effects of past � activities in the watershed (e.g. land use activities in the watershed (e.g. land use conversions and alterations) conversions and alterations) � Develop and evaluate structural and non Develop and evaluate structural and non- - � structural best management practices (BMPs) in structural best management practices (BMPs) in order to: order to: � Restore natural systems Restore natural systems � � Address water supply issues Address water supply issues � � Address water quality issues Address water quality issues � � Provide flood protection Provide flood protection � � Develop floodplain information suitable for FEMA Develop floodplain information suitable for FEMA � Flood Insurance Rate Map (FIRM) updates. Flood Insurance Rate Map (FIRM) updates. 4 4
Flood Protection Water Quality Water Supply Natural Systems 5 5
Myakka River Watershed Initiative Myakka River Watershed Initiative Upper Myakka Topographic Water Budget Information Watershed Evaluation Watershed Mgmt. Plan Implementation Adaptive Mgmt. of BMPs Monitoring Maintenance of Watershed Parameters and Models 6 6
Water Budget Modeling Water Budget Modeling � Modeling objectives Modeling objectives � � Model setup and calibration Model setup and calibration � � Initial model scenarios: Initial model scenarios: � � Historical Conditions Historical Conditions � � Existing Conditions Without Irrigation Existing Conditions Without Irrigation � � Future Conditions Future Conditions � � Next steps: Flatford Swamp hydroperiod Next steps: Flatford Swamp hydroperiod � restoration alternatives restoration alternatives 7 7
Modeling Objectives Modeling Objectives � Estimate the excess Estimate the excess � flows flows � Investigate linkages Investigate linkages � between land use/ land between land use/ land practices and excess practices and excess flows, flows, � Develop time Develop time- -series of series of � flow rates for possible flow rates for possible pollutant load modeling, pollutant load modeling, � Evaluate alternative Evaluate alternative � management scenarios management scenarios for restoring the natural for restoring the natural hydrology of the Upper hydrology of the Upper Myakka River Myakka River Watershed, and Watershed, and � Simulate hydroperiods of Simulate hydroperiods of � the Flatford Swamp the Flatford Swamp under historic, existing, under historic, existing, and proposed conditions and proposed conditions (This may also become (This may also become necessary in other necessary in other areas). areas). 8 8
Modeling Objectives - - Exclusions Exclusions Modeling Objectives � Flood Protection Evaluations Flood Protection Evaluations � � Water Quality Simulations Water Quality Simulations � � Local Local- -Scale Features and Process Evaluations: Scale Features and Process Evaluations: � � This is a sub This is a sub- -regional model with spatial scales regional model with spatial scales � appropriate for sub- -regional evaluations. regional evaluations. appropriate for sub � Evaluation of alternative management scenarios and Evaluation of alternative management scenarios and � hydroperiods of specific wetlands may require the hydroperiods of specific wetlands may require the development of one or more local- -scale models. scale models. development of one or more local � This sub This sub- -regional model may provide boundary regional model may provide boundary � conditions to future local scale models. conditions to future local scale models. 9 9
Model Tool Selection: MIKE SHE Model Tool Selection: MIKE SHE � Fully Fully- -coupled coupled � groundwater groundwater and surface and surface water models water models � Coupled with Coupled with � dynamic dynamic streamflow streamflow routing model routing model � Represents all Represents all � of the major of the major processes of processes of the land- -based based the land portion of the portion of the hydrologic cycle hydrologic cycle 10 10
Model Setup and Calibration Model Setup and Calibration � 2 2- -layer groundwater model representing the upper and layer groundwater model representing the upper and � lower surficial aquifer system lower surficial aquifer system � 125 x 125 125 x 125- -meter (410 x 410 ft) grid cells in 3 meter (410 x 410 ft) grid cells in 3- -D D � groundwater and 2- -D surface water models D surface water models groundwater and 2 � 1 1- -D open channel flow model of the Myakka River plus 9 D open channel flow model of the Myakka River plus 9 � tributaries tributaries � Explicit representation of irrigation Explicit representation of irrigation � � Physically Physically- -based representations of ET and unsaturated based representations of ET and unsaturated � zone processes zone processes � Calibration Period: May 1999 Calibration Period: May 1999- -April 2006 April 2006 � � Verification Period: May 1994 Verification Period: May 1994- -April 1999 April 1999 � 11 11
Topography Topography and and Bathymetry Bathymetry � 125 meter 125 meter � grid cells grid cells � Recent Recent � LiDAR data LiDAR data � Adjusted in Adjusted in � water bodies water bodies using survey using survey data data 12 12
Land Use / Land Use / Land Cover Land Cover � Eleven (11) land Eleven (11) land � use categories, use categories, derived from derived from SWFWMD 2004 SWFWMD 2004 FLUCCS- -based based FLUCCS mapping. mapping. � Row Crops were Row Crops were � subdivided into subdivided into active and fallow active and fallow fields fields � Model Model � parameters parameters varied by land varied by land use: use: � ET ET � parameters, parameters, � overland flow overland flow � roughness, roughness, 13 13
Soils Soils � Five (5) Five (5) � representative soil representative soil types, based on types, based on NRCS mapping NRCS mapping � Model parameters Model parameters � varied by soil type: varied by soil type: Volumetric water Volumetric water � � contents at contents at saturation, field saturation, field capacity, and wilting capacity, and wilting point; point; Saturated and Saturated and � � unsaturated unsaturated hydraulic hydraulic conductivities; conductivities; Soil moisture Soil moisture � � Pomello – MW Drained retention retention Myakka – SP Drained characteristic characteristic Waveland – P Drained curves; curves; Eaugallie – P Drained Floridana – VP Drained Saturated zone Saturated zone � � drainage time drainage time constant constant 14 14
MIKE- -11 11 MIKE Network Network � 1 1- -D unsteady D unsteady- - � flow hydraulic flow hydraulic model of the model of the Myakka River Myakka River and nine (9) and nine (9) tributaries tributaries � Approximately Approximately � 100 surveyed 100 surveyed cross sections cross sections MIKE-11 Branch 15 15
Precipitation Precipitation � NEXRAD radar NEXRAD radar � rainfall data rainfall data � Gage corrected Gage corrected � by OneRain, Inc. by OneRain, Inc. � Hourly rainfall Hourly rainfall � time step time step � 265 pixels, 265 pixels, � approximately approximately 2 km x 2 km 2 km x 2 km 16 16
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