FHWA’s emergency-relief program funds are used to reimburse states for repairs to roads and bridges in the aftermath of a natural disaster. The agency also said it would provide more aid as damage assessments and reconstruction cost estimates are completed.

Water, Water Everywhere

The area’s water infrastructure may have suffered the biggest damage. Some municipal water authorities implemented “boil water” advisories as early as Friday. Several towns, including Boulder, asked residents to reduce water use, with no-flush rules in place to avoid further stress on compromised sanitation systems. In towns closest to the floodwaters, sewage backed up into homes through toilets and bathtubs.

Worse yet, some wastewater facilities south of Greeley, including those in Lyons and Evans, went off line completely, as silt levels peaked dangerously high and pipelines were clogged or washed away. Evans residents will be without running water for at least the next 10 days. Those living in homes with well water were advised to monitor pollutant levels closely as the waters recede.

“The worst of the damage, as much as we can tell so far, has been to the [sewage] pipelines near the rivers,” said Steve Ravel, a project manager with Hatch Mott MacDonald, a Lakewood, Colo., engineering firm specializing in wet infrastructure. “Thousands of feet of those have been washed away,” he said. “Some places are worse off, likely with severe damage to the treatment facilities themselves.” Ravel was inspecting water facilities in the Estes Park area early in the week.

Greg Roush, COO of Leonard Rice Engineers, Denver, said he expects some of the agricultural communities to see the most damage. “A lot of those canal head gates were wiped out, and that causes problems all around the [irrigation] system,” he said. “Also, most of their wells could be in danger and will need to be inspected.”

Safety officials also warned residents and rescue workers about dangerous debris and potentially toxic chemicals in the floodwaters, including oil, agricultural pesticides and raw sewage. They advised against wading through standing water and, whenever possible, avoiding skin contact.

The area’s largest and most fragile dams held, but safety inspectors are still unable to reach many of them to determine the extent of damage, if any. Several small earthen dams burst, and state officials were closely watching larger structures, such as the Evergreen Dam, 11 miles upstream from the small town of Morrison, west of Denver. The main street through the town of Evergreen was flooded and closed off on Friday, but the dam itself held.

Because Colorado is more often beset by drought than floods, there is no comprehensive flood-management system in place in many of the smaller cities.

“The major dams appear to have worked just fine,” Roush said. “But they had to release a fair amount of water to save the structures by lowering the levels.”