Surely it is far better to use a park as a very temporary flood relief area than to spend thousands on drainage which is only going to be used every 75 years? The water would gradually drain away once the rains stopped for a while. The footballers could survive without a park for a couple of weeks. This is a widely used method in this country. It is far more cost effective to flood a park, a golf course or grazing land than buildings. Another "natural" solution is to plant lots more trees in suitable parts of parks and sports grounds. Trees transfer millions of litres of water from the soil back into the atmosphere. Again far cheaper than artificial drainage.