Posts

Iowa Flood Center Deploys Rain Gauges

Jim Niemeier installs an Iowa Flood Center rain gauge and soil moisture platform in NE Iowa.

This time of year, nothing interests farmers — and most other Iowans as well — more than rainfall. Nearly every conversation you hear includes some version of “Is it going to rain today?” Or if it has rained recently, you’ll hear “How much did we get?”

The Iowa Flood Center (IFC) is helping answer the second question with a high level of accuracy, thanks to new state-of-the-art technology. IFC researchers have designed and installed 20 state-of-the-art rain gauges with soil moisture probes in the Turkey River watershed in northeast Iowa, with a few more gauges in the South Fork of the Iowa River watershed (Franklin, Hamilton, and Hardin counties) and the Walnut Creek watershed (Jasper County).

“Rain is critical to so many human activities,” says Witold Krajewski, director of the Iowa Flood Center. “These instruments offer access to real-time information that people need.”

IFIS_raingaugenetwork

A total of twenty-eight Iowa Flood Center rain gauge and soil moisture platforms were deployed across three Iowa watersheds in April 2013.

In addition to measuring precipitation totals, the new gauges also measure moisture and temperature of the soil. The units are solar powered and transmit data via a built-in cell modem. The information is displayed on IFIS with a user-friendly graphic interface.

To view real-time precipitation, soil temperature, and soil moisture data from the instruments, visit IFIS:

  1. Click ‘Launch’.
  2. Choose the State Overview option on the dashboard and click ‘Launch’.
  3. In the upper right corner of the screen, hover your mouse over the DATA RESOURCES tab and click the box next to Rain/Soil Moisture Gauges.
  4. Click on a gauge icon to get more details from that location.
  5. From here, you can click to view additional rain gauge or soil moisture info for the site.
In IFIS, users can view real-time data from the gauges including soil moisture and soil temperature at depths of 2", 4" 8" and 20" near the gauge.

In IFIS, users can view real-time data from the gauges including soil moisture and soil temperature at depths of 2″, 4″ 8″ and 20″ near the gauge.

The new deployment of rain gauges is part of the Iowa Flood Studies project, also known as IFloodS, undertaken this spring in partnership with NASA. IFloodS researchers are collecting ground data across Eastern Iowa as part of NASA’s Global Precipitation Measurement Mission, an international satellite mission that will set a new standard for global precipitation measurements from space.

Based at IIHR—Hydroscience & Engineering at the University of Iowa, the Iowa Flood Center provides accurate, state-of-the-science-based information to help decision-makers, individuals, and communities better understand their flood risks.

IFC Stream Sensors: Built to Last

The Iowa Flood Center’s stream-stage sensors, mounted on bridges around the state, proved their resilience last week when floodwaters swept through Eastern Iowa. Last Wednesday, at least two of the IFC sensors in the Clear Creek watershed seem to have been overtopped by floodwaters and survived to send more data once the water receded.

The boxes housing the sensors are designed to be submerged in water and still function after the water subsides, says IFC Director Witold Krajewski. “Now we have field proof that the design was successful,” he explains. While the sensors are underwater, they stop sending data. Users of the Iowa Flood Information System (IFIS) will note this absence of data as a white or blank space in the graphic representation of the water levels (see image below).

BridgeSensor_nodata

Gaps in recorded data from this gage over Clear Creek indicated the sensor could have been submerged in floodwaters during heavy rains on April 18, 2013.

Krajewski says that he does not have complete proof that the sensors were submerged, since the sensors do not “see” the distance when water levels are closer than about a foot from the sensing unit. Despite this, he believes the pattern of the reported data strongly suggests that they were in fact underwater.

If you have photos taken during the recent flood event that show the IFC sensors or their bridges actually underwater, please send them to sara-steussy@uiowa.edu.