function [sed_depth1]=read_depth(distance,sed_depth);
%
% this program returns the sediment depth 
% if the distance of the location  from
% the shore is less than 10 miles
%
for ij=1:length(sed_depth(:,1))
if sed_depth(ij,1)>=distance 
sed_depth1=sed_depth(ij,2);
break
else
end
end