1 / 15

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

weston
Download Presentation

Review of ALDOT Draft Concept Design Report

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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

More Related