In its early history，Chicago had floods frequently，especially in the spring，making the streets so muddy that people，horses，and carts got stuck.An old joke that was popular at the time went something like this：A man is stuck up to his waist in a muddy Chicago street.Asked if he needs help，he replies，No，thanks.I've got a good horse under me.The city planner decided to build an underground drainage （排水） system，but there simply wasn't enough difference between the height of the ground level and the water level.The only two options were to lower the Chicago River or rais