Measuring a flood

U.S. Geological Survey field crews are measuring flooding across Arizona as warm rain causes increased runoff from melting snow.

In just the past few days, parts of Arizona have seen record levels of snowfall.

We’ve also had plenty of rainy days in the Desert Southwest.

Last October, the national weather service recorded 1.32 inches of rain, making it the wettest O ctober to date.

Nine USGS crews measure floodwaters and verify stream gage operations.

There are about 225 USGS-operated stream gauges in Arizona that measure water levels, streamflow and rainfall.

When there is a rise in rain or snowfall, the network will increase the gauge that helps measure roughly how much rain is falling.

These gauges are placed beside a “well” and measures elevation or gauge height.

Hugh Darling, field office chief for USGS, said, “we try to get out and make a discharge measurement which means that we go out and we measure how much of that water is coming down at a specific location.”

Flooding is defined by higher than normal flows of water.

“A real flood is when we are looking at extreme height maybe 90 percentile of the flow,” said Darling.

When flooding occurs, USGS crews make numerous flood measurements to verify the data. USGS provides to federal, state and local agencies, as well as to the public.

The USGS crews are never in one place.

Each crew is mobilized, moving site to site to collect water flow data using specific equipment.

“What we do then is we mobilize we have the equipment that we use in floods just basically for floods and we get out off bridges cable ways anyway we can and get measurements and directly measure that flow to help us notify the public when those high waters are coming,” said Darling.

This data is available to the public so they know when high waters are approaching.

The Colorado River and Hila river are both within levees and rarely flood.

Hence, local flood warning areas usually reach beyond Y uma .

“When you have a big urban area such as that with a lot of pavement that water has nowhere to go but into the streams and into the retention bases into the lower areas so that can cause bigger problems,” said Darling.

Another high-risk flooding area, is land that has been hit by a fire.

This information is critical for resource managers and emergency responders to help protect life and property.

If you are in a floodable area you can protect your property by doing research to see if your area is at risk.

For more than 125 years, the USGS has monitored flow in selected streams and rivers across the U.S.

A foot of water is about the size of a basketball, which means, the Colorado River has about 300 basketballs passing through every second.

With water flow of this speed and amount, people tend to not understand how dangerous floods can be.

“People tend to not realize the danger that is associated with floodwaters water moving from one point to another 6 feet and one second I think that’s what people really need to pay attention to is that power that is there with the flood water and don’t go into it,” said Darling.

You can access flooding information on USGS’s website.

USGS real-time maps of flood and high flow conditions for Arizona may be accessed online.