Syd, I don't know anything about California dirt but in Texas contractors often buy it and resell it. A neighbor of mine got a free one acre stock tank just so the dirt contractor could get the dirt. Sounds like someone is peeing on you and telling you its raining. Is there something wrong with your dirt? I'd check around for someone else. However, make sure that 1.You don't need the dirt for the dam 2. That your dirt has the right clay content and will hold water. 3.Check references on any dam builder and make sure he actually knows how to build a pond. A lot of the dozer operators know how to build roads and clear brush but not much more.