Cowl problems

Hey guys I have a 71 scamp /6 and every time it rains I get a little puddle of water on both front floor mats,the windshield has been replaced and tested and retested,firewall is solid and have no missing grommets or plugs.I was told the cowl is full of dead leaves and pine needles...etc and the only way to correct this is to remove the front fender and clean out water runoffs,I have never heard of this and I have owned two other old mopars and never had this issue.If this is true and I can get it cleaned out is there something I can do to prevent this?Thanks