The questions that you are posing are the same ones that i had a year ago. i bought a 7 acre pond that was about 30 years old and silted in around the edges. i cut part of the dam and let out a majority of the water through it. the remaining part had to be pumped out with a 6" diesal pump that took about six days. it then required using a 3" pump about once a week to keep it pumped out enough to dry. The drying part took about 3 months before any excavation could take place. mike Otto is supposed to finish this week but it is supposed to rain on friday which will require more pumping. I'm tired of pumping and my wife is tired of the mud.