Given a closed hyperbolic
3-manifold M, we construct a tower of covers with increasing Heegaard genus
and give an explicit lower bound on the Heegaard genus of such covers as
a function of their degree. Using similar methods, we prove that for any
𝜖 > 0 there exist infinitely many congruence covers {Mi} such that, for
any x ∈ M, Mi contains an embedded ball Bx (with center x) satisfying
volBx> (volMi)1∕4−𝜖. We get similar results for an arithmetic noncompact
case.