(plaintiffs, dairy farmers, constructed in-ground earthen trench silo to hold corn silage approximately 90-100 feet from neighbor's well; neighbors complained of odor in tap water; defendant ordered plaintiffs to remedy situation by various measures and later issued $33,772 civil penalty against plaintiffs for failure to comply with order and for violation of Clean Streams Law; violations not willful or reckless; case remanded to administrative board to recalculate penalty).