Update to Loxahatchee River Coordinating Council

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Update to Loxahatchee River Coordinating Council

• L-8 Reservoir Water Quality
• Flow-way 1 Water Delivery Test
• G-92 Structure Replacement
• September 29, 2008

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L-8 Reservoir August 2007
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Parameters (Cell 3) Sampling Depth Sampling Depth Sampling Depth
Parameters (Cell 3) 0.5 m 6.5 m 12.5m
Temperature 27.7 23.4 21.9
D.O. 8.83 6.79 4.39
Specific Conductance 2853 2817 2816
pH 8.3 8.1 7.8
TSS lt3 lt3 lt3
TDS 1649 1644 1328
TKN .81 .97 .87
Tot. Kjeldahl N 0.81 0.97 0.87
Nitrate/Nitrite lt0.005 0.123 0.130
Ammonia lt0.005 lt0.005 lt0.005
Total Phosphorus 0.006 0.008 0.023
Ortho-Phosphorus 0.006 0.002 0.005
Chlorides 442 614 633
Sulfate 165 229 236
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Parameters (Cell 6) Sampling Depth Sampling Depth Sampling Depth
Parameters (Cell 6) 0.5 m 6.5 m 12.5m
Temperature 27.9 23.4 22.3
D.O. 10 7.36 5.01
Specific Conductance 3801 3809 3835
pH 7.9 7.7 7.6
TSS 5 3 lt3
TDS 2275 2247 2317
TKN 1.12 1.07 1.15
Tot. Kjeldahl N 1.0 0.86 0.84
Nitrate/Nitrite 0.118 0.206 0.308
Ammonia lt0.005 0.009 lt0.005
Total Phosphorus 0.010 0.018 0.022
Ortho-Phosphorus lt0.002 lt0.002 lt0.002
Chlorides 943 895 914
Sulfate 347 329 334
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Results

• Similar to historical for WY 05 WY 08
• Lower concentrations of nutrients in cells than
  in either L-8 or M-Canal
• No metals exceeded WQ criteria
• Class I/III criteria exceeded for Specific
  conductance, TDS, Chlorides and Gross Alpha
• Levels comparable to current cell historical
  levels levels of parameters in exceedence are
  expected to decrease as reservoir is operated

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Mixing Zone Boundaries
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FLOW-WAY 1 TEST

• PURPOSE To test water delivery from the
  regional water system to the Loxahatchee River
  Basin using the existing infrastructure
• TEST DATE - July 1 July 3, 2008

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Flow-way 1
G-160
Northlake Bridge
Control 2 Pump Station
G-161
M Canal Widening
Grassy Waters Preserve M Canal
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TEST CRITERIA

• Establish baseline stages/flow rating curves
• Control GWP releases to limit effect on apple
  snails
• Release 150 cfs at Control 2, 100 cfs at G-161,
  100 cfs to NWFLR
• Maintain appropriate stages at GWP, G-161 and
  G-160
• Ensure coordination with stakeholders
• Measure water flow at critical locations
• Obtain water quality samples during test

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RESULTS
DATE Calculated Daily average flow (cfs) Calculated Daily average flow (cfs) Calculated Daily average flow (cfs) Calculated Daily average flow (cfs) Calculated Daily average flow (cfs)
CTRL 2 G-161 G-160 G-92 Lainhart Dam
7/1/08 147 41 73 110 128
7/2/08 147 91 160 138 200
7/3/08 143 50 206 71 215
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Measured Flows
DATE Flow Station Flow Station Flow Station Flow Station
Ctrl 2 G-161 G-160 E. Perimeter Canal
7/2/08 150 - 100 35
7/3/08 - 95 80 -
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Measured Avg. Daily Water Levels
DATE Stage Elevation (feet NGVD) Stage Elevation (feet NGVD) Stage Elevation (feet NGVD)
GWP (G-161 HW) G-161 TW G-160 HW
7/1/08 18.18 16.14 15.03
7/2/08 18.04 17.12 15.13
7/3/08 18.15 17.10 14.98
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Conclusions

• Confirmed that if replacement water is available,
  structures can be operated to deliver flow
• Confirmed 150 cfs at control 2, but only 35 cfs
  at E. perimeter canal
• G-161 operated to deliver 100 cfs to C-18
• Flow to NWFLR exceeded 100 cfs during test period
• Each structure is critical and operation must be
  synchronized to achieve results
• Measured flows agreed with estimated

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G-92 Structure Replacement
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G-92 StructureProposed Design Location

• New in-kind (single barrel, box culvert) will be
  installed to maintain flood protection and
  conveyance
• Located adjacent to existing structure
• Existing structure to be demolished

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G-92 StructureBackground

• Structure supplies water from the C-18 canal to
  the Loxahatchee River via the South Indian River
  Drainage District canal C-14
• Erosion and structure deterioration has limited
  structure capacity
• Failure of the existing structure became critical
  during 2004 hurricane season

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G-92 StructureBenefits of New Structure

• Reliability
• Extended service life
• Remote operation
• Public safety
• Flood protection
• Water delivery

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G-92 StructureOperation

• New structure will not deviate from existing
  operational criteria.
• Remote operation through telemetry

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G-92 Structure Replacement Schedule

• Bid opening scheduled for September 29, 2008 at
  230 p.m.
• Construction start late November to early
  December 2008
• Construction time frame - 300 days