Design and Construction of a Flow Equalization Basin (FEB) to Optimize Performance of Everglades Stormwater Treatment Areas (STAs)

Transcription

1 Design and Construction of a Flow Equalization Basin (FEB) to Optimize Performance of Everglades Stormwater Treatment Areas (STAs) American Water Resources Association 2016 Annual Water Resources Conference November Orlando, Florida Session 29: Reservoir Design and Operation

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3 57,000 Acres of Stormwater Treatment Areas (STAs) Built and Operational in 2012 STAs provide treatment for Total Phosphorus Loading (TPL) from Urban and Agricultural Areas TPL Reduction 170ppb to as low as 12ppb $1.8 billion invested GOAL: 10ppb TPL Stormwater Treatment Areas 1994: 4,000 acres 1999: 9,000 acres 2000: 18,000 acres 2003: 35,000 acres 2004: 40,000 acres 2006: 45,000 acres 2012: 57,000 acres Stormwater Runoff (Pulse Flows) Reduce STA Effectiveness Reduced Treatment Time Soil Degradation Damage to Vegetation SFWMD 3

4 2012 SFWMD Started Implementing Restoration Strategies Program Suite of Additional Water Quality Projects Optimize Existing Water Quality Infrastructure Address Pulse Flow Issues and Reduce TPL to 10ppb Plan Included 6 Projects Valued at $880M 4 120,000 Acre-Feet of Additional Water Storage Design and Construction of Flow Equalization Basins (FEB) to address peak flow attenuation and improve water quality 6,500 Acres of STA Expansion

5 Concept of FEB Attenuation of Pulse Flows Optimized Hydropatterns in STAs Reduced Flow Volumes/Velocities Lower Peak TP Loading Rates Restoration Optimization 5 Cost Effective Reduced STA Expansion Environmentally Preferable

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7 Support and Optimize STA-3/4 and STA 2/Compartment B Provide Stormwater Flow Equalization Reduce peak loading Temporarily store stormwater runoff Benefits Prevent STA Damage Minimize vegetation stress from prolonged dry / wet conditions Reduce soil oxidation, TP reflux Improve STA performance 7 Reduce STA water deliveries during dry season

8 Support the Long-Term 10 ppb TPL Objective Achieve Greater Periods of Treatment Time Increasing the Treatment Performance Provide Additional Operational Flexibility 8

9 Historical Inflows Stormwater Runoff from Central Flow Path Canal Flows from S-2, S-7, and S-8 Water Basins Direct Precipitation Predicted Outflows Evapotranspiration Seepage STA Releases 9

10 Consider Existing Infrastructure Pump Stations G-370, G-372, G-434, G-435 Water Control Structure G-373 Power Supply US Highway 27 Adjacent Farmland and Holey Land No Additional Pump Stations Low Hazard Impoundment Classification STA 3/4 North Perimeter Levee Looking East at G-370 STA 3/4 Inflow Canal Looking East from US HWY 27 at G-434 Allows for reduced levee height and reduces construction cost Not For Flood Control $60M Construction Budget 10

11 Utilization of Previous Construction Existing Scraped Area Existing Seepage Canal Existing Agricultural Canals Utilization of Existing Materials Seepage Canal Excavation Stockpiles Sorted/Processed Material Stockpiles Utilization of Existing Infrastructure No new Pump Stations use G-370 (NNRC) and G-372 (Miami Canal) Incorporation of Existing STA 3/4 Inflow Canal Levee Embankment for southern embankment 11 Solar Powered Water Control Gates

12 13,500 Acres 60,000 Acre-Feet Temporary Storage Uniform North-South Flow 2 Inflow Structures 11 Outflow Structures 2 Bypass Structures 13 Miles of New Perimeter Levee 7 Miles of New Above Ground Inflow Channels 12

13 Northeast Access Road Inflow STA-3/4 Structure Supply Canal G-720 West 13 Miles Type I Levee 6.7 Miles 60,000 Interior ac-ft Flow Conveyance Attenuation 17 - Stilling Levee 2 - End of Levee Basin Wells (4) Turnarounds 6,000 Turnout 11,000 ramps sf (5) Parking every Boat 2 Areas Ramps Miles 3,400 ft. Segments of Connecting Perimeter Seepage Canal G-370 Inflow Access Structure Road Outflow Structures G-721 G-722W G-722 2,700 ft. Collection and Conveyance Seepage Canal Collection & Outflow Structures G-723N & G-723S G-370S Upgrade Outflow Structures G-724 (A-J) STA-3/4 Inflow Canal North 8.4 Miles Type II Levee 13

14 2,775 cfs 3-Bay Reinforced Concrete Gated Spillway 11 x 20 Vertical Lift Stainless Steel Roller Gates SCADA Control Commercial Electric Power / Portable Backup G-720 Layout 3-D Model Looking North 2,020 Cubic Yards of Concrete Silica Fume and Crystalline Concrete Waterproofing Admixtures 270 Tons of Steel 14 $3.9M

15 1,850 cfs, 2 - Bay Reinforced Concrete Gated Spillway 10 x 20 Vertical Lift Stainless Steel Roller Gate Remote SCADA Control Commercial Electric / Backup Supplied by G-370 G-721 Layout 3-D Model Looking North 1,263 Cubic Yards of Concrete Silica Fume and Crystalline Concrete Waterproofing Admixture 168 Tons of Steel 15 $2.8M

16 Inflow from Pump Station G- 372 (Miami Canal) through G-720 2,775 cfs to G cfs to STA-3/4 Inflow from Pump Station G- 370 (NNRC) through G-721 1,850 cfs to G cfs to STA-3/4 G Week Time to Fill to 12.5 feet NGVD G TuFlow Model

17 DRY YEAR 2007 Modeled FEB Attenuated 24% of all Miami and NNR Canal Inflows. 100% of Inflows Addressed by FEB/STA-3/4 System WET YEAR 2008 Modeled FEB Attenuated 26% of all Miami and NNR Canal Inflows. 93% of Inflows Addressed by FEB/STA-3/4 System G-724 A-J Utilized to Convey 18% of FEB Releases to STA-3/4. 17

18 DRY YEAR WET YEAR UNITS Acre-ft Acre-ft Total Volume Captured by FEB/STA-3/4 System 158, ,577 Total Volume of Diversions 0 33,848 Net Inflow to FEB (G-720 and G-721) 38, ,204 Total Outflow through G ,606 90,767 Total outflows through G-724 (A-J) ,275 Note: -Modeling based on inflows to STA-3/4 at 1,000cfs below and 2,000cfs above a NFSL of 1 feet NAVD 88. -Results provided by NOVA Consulting.

19 2,000 cfs 3 - Barrel Reinforced Concrete Box Culvert 10 x 10 x 600 Non-gated Culvert Structure 3,523 Cyds Concrete 468 Tons Steel $2.6M 3-D Model Looking Northwest 19 Depth of structure complicated construction and design

20 2,000 cfs 3 - Barrel Reinforced Concrete Gate Culvert 10 Feet Tall; 10 Feet Wide; 31 Feet Long Stem Operated Vertical Lift Slide Gates Remote SCADA Commercial Power / Backup Power Supplied by G-370 G-722 Layout 3-D Model Looking South 1,172 Cubic Yards of Concrete Silica Fume and Crystalline Concrete Waterproofing Admixtures 156 Tons of Steel 20 $2.0M

21 150 cfs Single Barrel Reinforced Concrete Gate Culvert 7.5 x 7.5 x 460 G-723 Layout 2 - Stem Operated Vertical Lift Slide Gates G-723N G-723S G-723 Profile 1,037 Cubic Yards of Concrete Silica Fume and Crystalline Concrete Waterproofing Admixtures 138 Tons of Steel 21 $2.0M

22 10 Structures Along South Side of A-1 FEB Each Structure is 200 cfs, 1 - Barrel Reinforced Concrete Gate Culvert 6 x 6 Rubicon Solar Powered Vertical Lift Aluminum Slide Gates Remote SCADA Solar Charged Battery Manual or Portable Generator Backup Typical Stem Slide Gate 311 Cubic Yards of Concrete per structure Silica Fume and Crystalline Concrete Waterproofing Admixtures 42 Tons of Steel per structure 22 $8.2M

23 23 Construction Cost: $61.7M 15 water control structures (10 are solar powered) 2,100 tons of steel / 16,500 CY of concrete 21 miles of earthen levees (1.6M cubic yards of fill) 3.1M cubic yards degraded Backfilled 113 miles of agricultural swales Up to 150 construction personnel onsite daily Ton Articulated Dump Trucks used Inflow capacity: 4,600 cfs Outflow capacity: 4,200 cfs

24 Performance Metric Water Year 2016 Simulated Performance Inflow Volume (acre-feet) 230, ,000 Outflow Volume (acre-feet) 108, ,000 Inflow TP Conc. (ppb) Outflow TP Conc. (ppb) TP Load Reduction (%) TP Load Reduction (metric tons) Source: South Florida Water Management District

25 Owner/Operator SUBCONSULTANTS LEAD DESIGN 26

26 Restoration Strategies Regional Water Quality Plan, South Florida Water Management District, April Science Plan for the Everglades Stormwater Treatment Areas, South Florida Water Management District, June 2013.

27 G-722W and G-722 G-722W Bypass G-721 Inflow Channel G-722 Release to NNRC. Max Outflow = 2,000 cfs G-723 Outflow Canal Bypass Seepage Collection Outflow Canal Low Flows Max Outflow = 225 cfs G-724 (A-J) o Gravity Flow Discharge to STA-3/4 Inflow Canal o Max Outflow = 2,000 cfs G-724 A-J TuFlow Model G-723 G-722 W & G-722