Related Clues:

• Make more navigable, as a channel
• Increase in depth
• The way to dredge the river enclosure?
• Dredge the river enclosure
• Warm this, ta - eh?
• Get farther down
• Hideaway in which to piddle about in sink
• Make harder to fathom
• Warm through
• Intensify, as feelings
• Warm, as leftovers
• Dredge, say
• Excavate energy in Germany beside enclosure
• Dig further down
• Bird on river to get more down