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HomeMy Public PortalAbout160518_BCAG_Meeting4Brewster’s Landings Coastal Change and Adaptation Brewster  Historical  Coastline   Change:  1951  -­‐  2009   — Do  Nothing   — Manage  Retreat   — Protect  Landing   — Native  Vegetation   — Beach  Nourishment   — Sand  Fencing   — Re-­‐grade/Clean  up  After  Storms   — Fiber  Rolls/Coir  Envelopes  (biodegradable)   Preliminary  Adap?ve  Planning  Spectrum     for  Brewster’s  Public  Landings   — Provide  Alternate  Access   (e.g.,  shuttle)   Coastal  Engineering  Structures   — No  new  CES   — Not  allowed  on  dunes  per  MA  Wetlands   Protection  Act   — May  be  allowed  on  coastal  banks  for  pre-­‐1978   buildings,  but  does  not  apply  to  Brewster’s   landings  (no  coastal  bank  and  no  buildings)   — Existing  CESs:  Maintenance/Repair  allowable   but  Town  would  need  to  own  the  structure   Level  of  Review/PermiJng   — Town  (Cons.  Commission):  all  projects   — Potential  state  review  triggered  by:     — Work  below  Mean  High  Water   — Presence  of  rare  species  (e.g.,  shorebirds)   — Additional  permits  needed   — Additional  review  for  State-­‐owned  property   Paine’s  Creek  –  Recent  Adapta?on   Before  (May  2010)  After  (May  2015)   Image  source:  Google  Earth   Breakwater  –  Recent  Adapta?on   Sept.  2015  Jan.  2016   Image  source:  Greg  Berman   Wing  Island   Wing  Island  –  Assessment     — Undeveloped  area  bounded  by   — Creeks  and  marsh  (south,  east,  west)   — Barrier  beach  system  with  salt  marsh  (north)     — Barrier  beach  shoreline  has  eroded  slightly:   on  average  ~0.25  ft/  year  between  1951-­‐2009   — Movement  has  occurred  east  near  the  inlet   — Shoreline  partially  protected  by  salt  marsh,   so  erosion  may  continue  to  be  limited   — Footprint  of  the  island  likely  to  shrink  with   storms  and  sea  level  rise,  and  inlet  opening   Paine’s  Creek   Paine’s  Creek  –  Assessment   — Inlet  fronted  by  a  coastal  beach  stabilized  by:   — Shore-­‐parallel  revetment  with  end  groins  (‘1950s)   — Riprap  wall  protecting  the  culvert  and  parking  area   — Revetment  will  provide  limited  protection  to   beach  from  erosion     — Scour  may  cause  inner  creek  mouth  to  erode   — Landing  likely  to  experience  increased  flooding   from  storms,  SLR,  and  elevated  wetland  water   levels   Paine’s  Creek  –  Poten?al  Impacts   Potential  Flooding  Impacts  to   Water  Level    Resource  Access  Parking   MHW  +  2  ft   (surge  or  SLR)   Beach  /  marsh   partially  floods  No  Impact  No  Impact   MHW  +  4  ft   (surge  or  SLR)   Beach  /  marsh   floods   Access  to  beach   floods  50%  impact   MHW  +  8  ft  (4  ft   surge  +  4  ft  SLR)   Resource  fully   floods   Access  to  resource   &  parking  floods  100%  impact   — Revetment  will  provide  limited  protection  to  beach  from  erosion*   — Scour  may  cause  inner  creek  mouth  to  erode   Mant’s  Landing   Mant’s  Landing  –  Assessment   — Coastal  beach  with  no  dunes  or  structures   bordering  salt  marsh   — Significant  erosion  occurred  since  1951   (average  ~1.7  ft/yr)   — Barrier  beach  migration  west  of  parking  lot   likely  to  continue  unimpeded   — Landing  also  likely  to  experience  increased   flooding  from  storms,  SLR,  and  elevated   wetland  water  levels     Mant’s  Landing  –  Poten?al   Impacts   Potential  Flooding  Impacts  to   Water  Level    Resource  Access  Parking   MHW  +  2  ft   (surge  or  SLR)   Reduced  beach,   flooded  marsh  No  impact  No  impact   MHW  +  4  ft   (surge  or  SLR)   Reduced  beach,   flooded  marsh   Flood  impacts   parking  access  50%  impacted   MHW  +  8  ft  (4  ft   surge  +  4  ft  SLR)   No  beach,  no   marsh   Flood  prevents   parking  access  100%  impacted   — Inland  migration  of  western  barrier  beach  likely  to   continue   Saint’s  Landing   Saint’s  Landing  –  Assessment   — Beach  in  a  groin  field,  backed  by  cliff  top   dunes     — Shoreline  has  retreated  (~0.7  ft/yr)   — Dunes  &  elevation  provide  flood  protection  to   parking  area,  for  reduced  flood  impact   — Shoreline  likely  to  continue  retreat,  with   groins  eventually  undermined  at  landward   end   — Parking  lot  drainage  via  culvert  on  beach  will   induce  erosion     Saint’s  Landing  –  Poten?al  Impacts   Potential  Flooding  Impacts  to   Water  Level    Resource  Access  Parking   MHW  +  2  ft   (surge  or  SLR)  Reduced  beach  area  No  impact  No  impact   MHW  +  4  ft   (surge  or  SLR)  Reduced  beach  area  No  impact  No  impact   MHW  +  8  ft  (4  ft   surge  +  4  ft  SLR)   Beach  entirely   floods  No  impact  No  impact   — Inland  retreat  of  shoreline  likely  to  continue   Breakwaters   LiPle  Breakwater  –  Assessment   — Coastal  beach  with  groin  on  west  side,  and   revetment  to  the  east   — No  significant  shoreline  movement  since   2009,  possibly  due  to  salt  marsh   — Cliff  top  dune  erosion  has  been  addressed   with  nourishment  and  sturdy  drift  fencing   — Future  erosion  may  be  limited,  but  access   could  become  restricted  by  flooding   LiPle  Breakwater  –  Poten?al  Impacts   Potential  Flooding  Impacts  to   Water  Level    Resource  Access  Parking   MHW  +  2  ft   (surge  or  SLR)   Reduced   beach  area  No  impact  No  impact   MHW  +  4  ft   (surge  or  SLR)   Reduced   beach  area   Flood  impedes   access  to  parking   No  impact,  but  no   access  to  parking   MHW  +  8  ft  (4  ft   surge  +  4  ft  SLR)   Reduced   beach  area   Flood  impedes   access  to  parking   No  impact,  but  no   access  to  parking   — Limited  shoreline  movement  expected  in  the  near   term   Breakwater  Landing  –  Assessment   Note:  Aerial  imagery  pre-­‐dates  recent  parking  redesign   — Beach  back  by  coastal  dune  east  of  coastal   structures   — Significant  erosion  occurred  since  1951   (average  ~1.8  ft/yr)   — Beach  and  dune  likely  to  continue  to   retreat,  which  new  parking  location  would   allow   — Landing  also  likely  to  experience  increased   flooding  from  storms  and  SLR   Breakwater  –  Poten?al  Impacts   Potential  Flooding  Impacts  to   Water  Level    Resource  Access  Parking   MHW  +  2  ft   (surge  or  SLR)   Reduced  beach   area  No  impact  No  impact   MHW  +  4  ft   (surge  or  SLR)   Reduced  beach   area  No  impact  No  impact   MHW  +  8  ft  (4  ft   surge  +  4  ft  SLR)   Beach  entirely   floods  No  impact  100%  impacted   — Beach  and  dune  likely  to  continue  to  retreat   Point  of  Rocks   Point  of  Rocks  –  Assessment   — Coastal  beach  backed  by  dune  and  located   behind  salt  marsh  area   — Accretion  since  1951  (average  ~0.7  ft/yr),  with   some  more  recent  erosion   — Shoreline  retreat  likely  to  continue,  but  salt   marsh  may  provide  some  protection   — Low  dunes  likely  to  migrate  landward  against   higher  uplands     — Landing  subject  to  increased  flooding   Point  of  Rocks  –  Poten?al  Impacts   Potential  Flooding  Impacts  to   Water  Level    Resource  Access  Parking   MHW  +  2  ft   (surge  or  SLR)   Reduced  beach   area  No  impact  No  impact   MHW  +  4  ft   (surge  or  SLR)   Beach  entirely   floods  No  impact  No  impact   MHW  +  8  ft  (4  ft   surge  +  4  ft  SLR)   Beach  entirely   floods   Access  to   beach  floods  No  impact   — Shoreline  retreat  likely  to  continue   — Low  dunes  may  migrate  landward   Ellis  Landing   Ellis  Landing  –  Assessment   — Coastal  beach  at  end  of  revetment,  with   parking  area  surrounded  by  dunes   — Significant  erosion  occurred  since  1951   (average  ~1.7  ft/yr)   — Beach  likely  to  continue  to  erode,  with   potential  scour  at  end  of  revetment   — Strategic  retreat  project  approved  in  2015   involving  drainage  improvements  and  dune   restoration   Ellis  Landing  –  Poten?al  Impacts   Potential  Flooding  Impacts  to   Water  Level    Resource  Access  Parking   MHW  +  2  ft   (surge  or  SLR)   Reduced  beach   area  No  impact  No  impact   MHW  +  4  ft   (surge  or  SLR)   Beach  entirely   floods  No  impact  No  impact   MHW  +  8  ft  (4  ft   surge  +  4  ft  SLR)   Beach  entirely   floods   Access  to  beach   floods  ~15%  impact   — Beach  likely  to  continue  retreat   — Strategic  retreat  project  may  help  protect  resource   Linnell  Landing   Linnell  Landing  –  Assessment   — Coastal  beach  between  2  groins,  backed  by   parking  lot  surrounded  by  dunes  on  east   and  west  sides   — Moderate  erosion  since  1951  (~0.3  ft/yr)   — Significant  recent  accretion  (>  5  ft/yr)  has   buried  eastern  groin   — Long  term  erosional  trend  may  continue   — Low-­‐lying  parking  area  may  be  subject  to   flooding  and  sand  accumulation  from   dunes   Linnell  Landing  –  Poten?al  Impacts   Potential  Flooding  Impacts  to   Water  Level    Resource  Access  Parking   MHW  +  2  ft   (surge  or  SLR)   Reduced  beach   area  No  impact  No  impact   MHW  +  4  ft   (surge  or  SLR)   Beach  almost   entirely  floods  No  impact  No  impact   MHW  +  8  ft  (4  ft   surge  +  4  ft  SLR)   Beach  entirely   floods   Access  to  beach   floods  ~60%  impact   — Long  term  erosional  trend  may  continue   — Parking  subject  to  flood,  sand  accumulation  from  dunes   Crosby  Landing   Crosby  Landing  –  Assessment   — Barrier  beach  and  coastal  dune  system   backing  to  wetlands   — Significant  accretion  historically  (~1.5  ft/yr   from  1951  –  2009)  and  recently  (>  6  ft/yr)  –   groin  to  the  west  is  almost  buried   — Accretion  may  continue  on  long  term,  but   potentially  impacted  by  storms  and  SLR   — Parking  lot  may  experience  increased   flooding  from  marsh  area   Crosby  Landing  –  Poten?al  Impacts   Potential  Flooding  Impacts  to   Water  Level    Resource  Access  Parking   MHW  +  2  ft   (surge  or  SLR)   Reduced  beach,   wetland  floods  No  impact  No  impact   MHW  +  4  ft   (surge  or  SLR)   Reduced  beach,   wetland  floods   Access  to  parking   floods  ~  50%  impact   MHW  +  8  ft  (4  ft   surge  +  4  ft  SLR)   Entire  resource   underwater   Access  to  parking   floods  100%  impact   — Accretion  likely  to  continue   — Main  impacts  will  be  from  flooding  and  storm  damage     Namskaket  Marsh   Namskaket  Marsh  –  Assessment   — Expansive  salt  marsh  with  numerous  creeks   leading  to  an  inlet   — Barrier  dune  and  beach  system  to  west  has   been  accreting   — East  shore  more  variable:  long-­‐term  erosion   (~1.2  ft/yr),  recent  accretion  (>10  ft/yr)   — Overall  dynamic  system  where  increased   flooding  may  affect  patterns   Adapta?on  Discussion   Poten?al  Commercial  Shellfish  Grants   Questions?