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Review of ALDOT Draft Concept Design Report

Review of ALDOT Draft Concept Design Report. By: Dennis Hatfield, LLPS Board. Overview. Bridge and pass draft design objectives Pass sediment budget model 6 possible designs Barney and Dennis preference Closing Comments. Draft Objectives . Reduction of average annual cost of $350,000

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Review of ALDOT Draft Concept Design Report

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  1. Review of ALDOT Draft Concept Design Report By: Dennis Hatfield, LLPS Board

  2. Overview • Bridge and pass draft design objectives • Pass sediment budget model • 6 possible designs • Barney and Dennis preference • Closing Comments

  3. Draft Objectives • Reduction of average annual cost of $350,000 • Maintain or improve existing water quality conditions • Minimize coastal impacts on GOM shoreline • Stabilize mouth of pass to existing shoreline • Widen pass south of Lee Callaway bridge • Narrow the pass north of the bridge/include sediment trap • Place material further down drift along GOM shoreline • New and improve dredging efficiency thru new contract specs

  4. Sediment Budget Model • Little Lagoon is a remarkable, prolifically productive, 8 mile long (e-), ¾ mile wide (n-s), sand dominated, brackish water coastal lake • Because of national publicity, low interest loans, federal flood insurance, and a general desire to live on or near the coast, dramatic development is ongoing • Wetlands are being damaged and destroyed and water quality is deteriorating • Nutrients and Fecal coli form measurements are up over the last 10-15 years and other pollutants are almost certainly on the rise • Little Lagoon circulation and turnover are poor and pollutant resident times are lengthy • Nutrients accumulate and we are suspicious that conditions are ideal for phytoplankton “blooms”

  5. Sediment Budget Model-2 • Little Lagoon is a remarkable, prolifically productive, 8 mile long (e-), ¾ mile wide (n-s), sand dominated, brackish water coastal lake • Because of national publicity, low interest loans, federal flood insurance, and a general desire to live on or near the coast, dramatic development is ongoing • Wetlands are being damaged and destroyed and water quality is deteriorating • Nutrients and Fecal coli form measurements are up over the last 10-15 years and other pollutants are almost certainly on the rise • Little Lagoon circulation and turnover are poor and pollutant resident times are lengthy • Nutrients accumulate and we are suspicious that conditions are ideal for phytoplankton “blooms”

  6. Alternate A

  7. Alternate B

  8. Alternate C

  9. Alternate D

  10. Alternate E

  11. Alternate F

  12. Barney and Dennis Preference-F • Expense problem with options A, B, C, D, concrete seawall, loss of public gathering • ALT C, E, F increase tidal prism 11%, 13%, 56% respectively compared to baseline • ALT C, F decrease channel shoaling from ~29,000 yds to ~21,000 yds (C), and ~12,000 yds (F) • ALT F model predicts more flood and ebb tidal delta shoaling • ALT F has smallest predicted annualized cost over 50 years, less than ½ of baseline and ALT C, and ALT E • Up front investment- ~$2MM (C), ~$130K (E), ~526K (F)

  13. Closing Comments • LLPS has stated intent to not object to modification of court order to move sand further down beach • LLPS expresses no current objections to plans to redesign pass and utilize sands for repair west of pass, we like option F? • LLPS will work with ALDOT on additional court order modifications-trigger language and process, shoal sand maintenance procedures, and depth requirements in maintenance phase of court order • Currently ALDOT is awaiting city draft language for court order which would allow dredge spoil placement further west of the pass than allowed by current court order • City has not yet obtained required permits from COE, ADEM, FWS

  14. GAPC Update • At recent meeting with Barnett Lawley LLPS GAPC application status was discussed • Problem remains while ADCNR is prepared to recommend designation as GAPC, ADEM must rewrite regulations concurrently for the designation to have meaning. • Since the 2 agencies have been separated this has been the holdup • Commissioner Lawley has promised to pursue/facilitate?

  15. Red Clay Update • Current legislative effort is dead • Legislative priorities gambling, and schools, County Commission did not support again • Will now try a “bottom up” approach and try to get individual municipalities to adopt standardized process and more comprehensive protection

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