https://www.scientificamerican.com/article/hurricane-harvey-houston-has-no-quick-way-to-get-rid-of-floodwater/

Hurricane turned Tropical Storm Harvey has pounded Houston since last Friday, dropping over 35 inches of water in some areas of Harris County within 72 hours. The heavy precipitation has led to massive flooding, leaving people either fleeing or stranded, waiting for rescue.

According to some estimates, the storm by Monday had already released 14 to 15 trillion gallons of water across the region. Rains have continued to thrash the city. Unfortunately, Houston has few options for draining its biblical deluge.