diff --git a/src/Utility/Particle_Tracking/particle.bp b/src/Utility/Particle_Tracking/particle.bp
index 575faf55..2127fdb1 100644
--- a/src/Utility/Particle_Tracking/particle.bp
+++ b/src/Utility/Particle_Tracking/particle.bp
@@ -2,10 +2,10 @@ Input for ptrack*
 1 nscreen
 0 mod_part (0: passive; 1: oil spill)
 0 ibiofoul (0: no biofouling; 1: with biofouling)
-1 ibf
-0 istiff
+1 ibf !(1: forward; -1: backward)
+0 istiff !1: fixed distance from surface
 0 ibnd_beh (behavior near bnd or wet/dry; 0: reflect off; 1: slide)
-1 -122.6 37.38 ics slam0 sfea0
+1 -122.6 37.38 ics slam0 sfea0 (from param.nml)
 0.01 140. 120. 30 720 40 !h0,rnday,dtm,nspool,ihfskip,ndeltp
 2 !# of particles
 1   0.432000000E+05   0.334902000E+06   0.293906000E+06  0. !particle ID, starting time in sec, starting x,y,z (<=0, relative to the instantaneous surface)
@@ -13,7 +13,7 @@ Input for ptrack*
 !Oil spill parameters needed only if mod_part=1
 1  3.0  0.2           !ihdf(0: constant diffusivity as hdc; 1: Smagorinsky),hdc,horcon (Smagorinsky coefficient)
 1  0                  !ibuoy (buoyancy off (0) or on (1)),iwind (wind effect off (0) or on (1))
-20.0                  !pbeach - % of stranding when particles reach shore
+20.0                  !set minimum percentage of stranding on shore (particles may be stranded if the random # exceeds this threshold)
 !start of biofouling paramaters, needed only if ibiofoul=1
 2.5e-3 0. 6.e-6 0.83 1.38   !bio_R0,bio_BT0,bio_BR,bio_den0 (\rho_0),bio_den_biolayer (\rho_D)
 
diff --git a/src/Utility/Particle_Tracking/ptrack4.f90 b/src/Utility/Particle_Tracking/ptrack4.f90
index f8aeb3ed..5189ebec 100755
--- a/src/Utility/Particle_Tracking/ptrack4.f90
+++ b/src/Utility/Particle_Tracking/ptrack4.f90
@@ -55,7 +55,13 @@
 !	  (8) nparticle: # of particles;					
 !	  (9) idp(i),st_p(i),xpar(i),ypar(i),zpar0(i): particle id, start time (sec),
 !		starting x,y, and z relative to the instant f.s. (<=0).		
-!         (10) additional parameters for oil spill
+!         (10) (additional parameters for oil spill) comment line
+!         (11) ihdf  : turn on Smagorinsky algorithm - off(0), on(1)
+!         (12) ibuoy,iwind: turn on(1)/off(0) buoyancy of particle; wind effect on(1)/off(0)
+!         (13) pbeach: set minimum percentage of stranding on shore (particles may be stranded if the random # exceeds this threshold)
+!         (14) (optional for biofouling) comment line
+!         (15) bio_R0,bio_BT0,bio_BR,bio_den0,bio_den_biolayer: init plastic radius (m),init thickness of fouling layer (m), 
+!                 bio growth (m/day),init density of plastic particle (kg/m^3), density of biofoul layer (kg/m^3)
 !										
 !	Output: particle.pth, particle.pth.more (more info), fort.11 (fatal errors).		
 !										
@@ -246,11 +252,6 @@ program ptrack
       enddo !i
 
 !...  Additional parameters for oil spill
-! ... Description of parameters
-!     ihdf  : turn on Smagorinsky algorithm - off(0), on(1)
-!     ibuoy : turn buoyancy of particle  - off(0), on(1)
-!     iwind : turn wind effect - off(0), on(1)
-!     pbeach  : set percentage of stranding on shore
 ! ........................................................
       if(mod_part==1) then
         read(95,*) !comment line
@@ -261,9 +262,6 @@ program ptrack
 
       if(ibiofoul/=0) then
         read(95,*) !comment line
-        !init plastic radius (m),init thickness of fouling layer (m), 
-        !bio growth (m/day),init density of plastic particle (kg/m^3),
-        !density of biofoul layer (kg/m^3)
         read(95,*)bio_R0,bio_BT0,bio_BR,bio_den0,bio_den_biolayer
       endif !ibiofoul/