Steep Slopes Hazard Map South Pender

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Steep Slopes Hazard Map
South Pender Island
00.511.520.25
Kilometers
Moderate Hazard (22.5 - 45 degrees)
High Hazard ( > 45 degrees)
Property Boundaries
Low Hazard (15 - 22.5 degrees)
Supportng  Da t a  and  Li mi  taaons ￿￿ 
 
 
This South Pender Island  Steep  Slopes  Hazard  Map  has  been  created  using  a  slope  gradient  generated  from  a  digital  elevaton  mo del  ￿
(DEM). A DEM is a digital representaton  of   gr ound  sur face  topogr aphy,  or   topogr aphi c  rel ief , bui lt  us i ng  remo t e  sens i ng  tec h￿niques and 
aerial  photography.  There  are  a  number  of  limitatons   i n  uul izing  aer i al  phot ogr aphs   to  devel op  Di g it al   El evavon Mode  l s   (DE￿￿ ￿M),  which 
should be noted when considering the spatal  res ol uuon  of  the  map ped  haz ard  areas .   The  qual i ty  of  the  DEM  may    ￿￿vary according to many 
conditons :  ter rai n  roughnes s,  samp l ing  dens i ty,  gr i d  res ol uuon  ( or  pi x el   si ze) ,   interpol alon al gori t hm,   v  ervc al  r esol uso￿￿￿￿￿n  and  terrain 
analysis algorithm. The quality of the air photos and the scale used may have affec t ed  the  DE M￿ resoluton,  as   the  ai r  phot os   ma y  not   have  ￿
captured all topographic elements, such as ravines, localized bluffs,  or   sma l l scal e  feat ur es .  The  ￿South Pender DEM was derived from the 
air photos flown   at   a  scal e  of   1: 16, 000,  wi  th  0. 5  m   ver rcal   accur acy  on  op￿￿en ground surfaces and 30 cm horizontal resoluton.  For   thos e  ￿
areas with extensive forest canopy, the elevaton  accur acy  coul d  var y  by  as   mu c h  as   hal f  of  the  tree  hei ght .  In  addi ion,   the￿￿ elevaton  dat a  ￿
(DEM)  does  not  include  mean  sea  level  for South  Pender Island  due  to  mean  sea  level  not  being  identfied  at  the  eme o f   t he  ai r  phot o  ￿￿￿
flight .  Ac cor di ngl y,  the  mi   ni mu m    ma pped  el evaaon  along  t he  s hor el i ne  i s 2m.    Class i fied St eep  Sl opes   Haza r d  ar eas  s mal l   er t ha￿￿￿n 36 square 
metres  have  been  filter ed  out   of   thi s  ￿map,  the  resoluton  of   thes e  ar eas   havi ng  been  deeme d  i ns i gni ficant   to  t he  pot eneal  geol ogic al  ￿￿￿
hazard.  
 
The  ratonal e  and  suppor t  for   the  cl as si ficacon of   S teep  Sl opes   Haza r d  desi gnagons i s   contai ned i n  the  rec ommend a eons   of   a￿￿￿￿￿ report 
prepared  for  the Islands  Trust by  Shane  Moore,  P.  Geo.,  C.  N.  Ryzuk  and  Associates.  Copies  of  the  report  (C.N.  Ryzuk  and  Associates, 
Geological Hazard Mapping Project, South Pender Island, December 2009) can be obtained by contactng  the  offices  of  t he  I s lands   Trus t. ￿￿￿

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