Texas Come Hell or High Water

A deluge shows how overbuilding at the edge of floodplains can put thousands of people at risk

Inching her Chevy van across water-covered roads and mud flats last week, Mayor Jo Mapel of Bailey's Prairie, Texas, couldn't begin to guess how huge the damage bill would be. Most of the ranching hamlet (pop. 634) near the Gulf Coast lay submerged under the dark red waters of the Brazos River and adjoining creeks. Said Mapel: "Nobody's escaping without big problems. This mess is going to be with us for months."

Across southeast Texas, the Brazos, Trinity and Colorado rivers, swelled by nearly 9 in. of rain that pelted their headwaters last month, overflowed their banks for miles, sweeping away...