While the cause for the derailment has not been officially determined, a disaster proclamation by the state's governor and local officials blamed flooding caused by two days of heavy rain for eroding the soil beneath the railroad tracks.
The public's interest in the train derailment is making it extremely hard for clean up and construction crews to get in and out of the area.
City spokesman Travis Olson says 12 blocks of the city with between 50 and 70 homes - were evacuated Thursday when the Rock River came out of its banks.
The train derailed early Friday just south of Doon in Lyon County, leaking oil into surrounding floodwaters from the swollen Little Rock River. 14 of the cars have been leaking oil since the accident, with officials estimating 871,000 litres of crude have seeped into floodwaters adjacent to the tracks.
BNSF Railroad is asking anyone with damage as a result of that derailment to contact them to get everything cleaned up and repaired.
Williams says clean-up crews are working to contain the oil as close to the derailment as possible using containment booms, skimmers and vacuum trucks.
European Union leaders to hold crisis talks on migration
Migrants not entitled to asylum should be returned directly to their country of origin and not via other countries, Macron said. Czech Prime Minister Andrej Babis said Friday he was also ready to start turning away migrants if Berlin and Vienna did so.
Sheriff Vander Stoep said, "There is so much food for the workers and for us at the incident command, it's just wonderful how little these communities come together".
A major part of that work includes building a temporary road parallel to the tracks to allow in cranes that can remove the derailed and partially submerged oil cars.
The train was carrying tar sands oil from Alberta to Stroud, Okla., for ConocoPhillips. ConocoPhillips spokesman Daren Beaudo said each tanker can hold more than 25,000 gallons (20,817 imperial gallons) of oil.
The derailment also caused concern downstream, including as far south as Omaha, Nebraska, about 150 miles (240 kilometers) from the derailment site.
Metropolitan Utilities District said it was monitoring pumps it uses to pull drinking water from the Missouri. It joins the Rock River a few hundreds yard west, which courses south into the Big Sioux River.
Despite the rising water outside, the oil spill turned Rock Valley's focus to the safety of the water inside, ultimately deciding to turn off all locally sourced water.