THE ACFT COLLIDED WITH A CHAIN LINK FENCE AND A DIRT BANK ON THE FINAL APPROACH JUST PRIOR TO TOUCHDOWN. THE FENCE WAS ABOUT A FOOT AND A HALF HIGHER THAN THE DIRT AND THE DIRT BANK WAS APRX AN EQUAL HEIGHT ABOVE THE RUNWAY. THE PLT HAD FLOWN THROUGH RAIN SHOWERS WHILE ENROUTE. HE REPORTED THAT HIS VERTICAL SPEED INDICATOR FLUCTUATED UNUSUALLY AND THE ALTIMETER WAS SLUGGISH. ON HIS APPROACH TO LAND THE PILOT REPORTED NOTICING THAT HE WAS LOWER THAN HE SHOULD HAVE BEEN. THE WEATHER WAS VMC BUT IT WAS A DARK NIGHT. ABOUT 75 FT SHORT OF THE RWY THRESHOLD THE ACFTS PROPELLER, FUSELAGE AND LANDING GEAR HIT AND KNOCKED DOWN PART OF A CHAIN LINK FENCE, INCLUDING A STEEL POST. THE LANDING GEAR COLLAPSED AND THE PROPELLER HIT THE DIRT BANK. THE ACFT BOUNCED AND LANDED ON THE BOTTOM OF THE FUSELAGE FT SHORT OF THE RWY. IT SLID DOWN THE RWY AND TO THE SIDE AN UNDETERMINED DISTANCE. (IT WAS MOVED PRIOR TO INVESTIGATION.) EXAMINATION OF THE PITOT STATIC SYSTEM REVEALED ABOUT 3 TABLESPOONSFUL OF WATER TRAPPED IN THE LINES.