(Switch hit his post right before this one; alot of the ?'s are dup's, but I,m gonna leave it)
gregWV,
OK, if I am reading your explanation correctly, the water never made it high enough to hit the spillway, right? Next, are you confident that the soil has suitable clay? Where did it come from (this sometimes contains a hint)? How did the top erosion occur...was it undermined by seepage below and then washed/carried away? Next, how did your contractor prepare the bond between the old dam top and the new work? Was the top of the old scraped down to good clay? Was it then scarred, disc'd, (or cored...kinda doubt it but gotta ask) to create a mechanical bond between the old and the new? How was the soil placed and compacted...was it just pushed into place in heaps and then he ran the dozer over it...or...was it layered in about 8 - 12" layers? I assume the only equipement was the dozer...what size/type (snapshot of the type/weight of the equipment; absent compaction equipment, this may make a slight diff)
I hope fillin' in these blanks will help to prescribe.
(edit) had another thought...assuming there was decent clay in the soil, was there suitable moisture in with it? Hopefully/presumably, it wasn't dry)
