Question: What did king john do to kenilworth castle?
Disambiguated questions and answers: question: What did King John build on Kenilworth Castle?
What did King John do to Kenilworth Castle in the area of water?
answer: outer bailey wall in stone, and Mortimer's and Lunn's Towers
improved the castle's water defences by damming the Finham and Inchford Brooks
Natural Questions answer: rebuilding and enhancing (from the Wikipedia article "Kenilworth Castle")