Archive for September, 2018

September 19, 2018

Critical Infrastructure Upgrades Since 1993

Water is one of the most useful things on Earth and also one the most powerful. As the Des Moines metro area prepared to celebrate 25 years of progress from the historic Flood of 1993, residents once again witnessed firsthand the devastating force of nature during the flash flooding of late June 2018, with pockets of the metro area receiving 6 to 10 inches in a matter of hours. Tributaries of the Raccoon River and Des Moines River reached record or near-record levels. The localized flash flooding caused significant damage to many homes and businesses.

After monitoring river projections through the late evening, Des Moines Water Works (DMWW) staff began flood preparations for the Fleur Drive Treatment Plant in the early morning hours of July 1. While the Raccoon River at Fleur Drive did not reach record stages like the Flood ’93, the physical and informational changes made since 1993 have been tested numerous times:

  • Levees surrounding the Fleur Drive Treatment Plant were built up an additional 6 feet.
  • Flood gates were installed around Fleur Drive Treatment Plant and George Flagg Parkway General Office.
  • Stormwater upgrades inside Fleur Drive Treatment Plant were made to protect against internal flooding during heaving rains.
  • Access to the Fleur Drive Treatment Plant during a flood event were improved with the Martin Luther King Jr. Parkway interchange construction.
  • Critical support functions at the General Office were relocated to ensure access of important data.
  • Two additional water treatment plants – L.D. McMullen Water Treatment Plant at Maffitt Reservoir and Saylorville Water Treatment Plant – were built to create redundancy in our water treatment capabilities.
  • Three Aquifer Storage and Recovery (ASR) wells were also constructed to provide redundancy.
  • Real-time river data from United States Geological Survey, National Weather Service and U.S. Army Corps of Engineers were made available. The availability to this important data is invaluable to staff for emergency planning and preparation.

(photo of Fleur Drive Treatment Plant flood gates during 2008 flood)

With these critical infrastructure upgrades, Des Moines Water Works is able to remain committed to providing safe, affordable and abundant water service, even in times of crisis.

Posted by: Laura Sarcone No Comments
Labels: , , , , Posted in About Us, Flooding, Infrastructure September 10, 2018

Gallery ‘Flooding Station’ 100 Years Old

Des Moines Water Works Fleur Drive Treatment Plant has the option of three different sources of raw water. The first and best source is a shallow groundwater collection system called the Infiltration Gallery. The Gallery system is a three-mile long, porous pipe constructed with concrete rings. The gallery runs parallel to the Raccoon River in Water Works Park from SW 46th Street to Fleur Drive. It collects naturally-filtered water from the sand and gravel of the river valley. The concrete rings are four and five feet in diameter and two feet long and are held slightly apart so water can trickle into the pipe. The Gallery system at Des Moines Water Works dates back to 1884, when the first 260 feet was constructed. By 1910, over 6,000 feet of Gallery had been excavated and placed in service.

Prior to 1910, when Des Moines’ water supply was deficient, trenches were dug in nearby sandbars or whole surfaces of sandbars were cleaned off to allow them to flood at a shallow depth and augment the water supply to the Gallery. After Gallery extensions were made in 1910, “emergency filters” were also constructed to collect water for infiltration. Thus began the construction of the current ponds in Water Works Park to augment the water supply to the Gallery.

During the drought of 1916 and after, extremely low water levels were artificially increased using a temporary pumping station to pump water from the Raccoon River onto a low-lying area. About five million gallons per day (mgd) were pumped onto the ground to flood an area of about four acres. Since this worked so effectively at increasing water supplies in the Gallery, it was decided to build a permanent pumping station at this location in 1918. It was placed into service in February 1919, and contained two motor-driven centrifugal pumps that could each pump 5 mgd. Since it was originally used to flood the land, it became known as a ‘flooding station,’ not pumping station.

One interesting fact about the Gallery flooding station is who the architect was: Norman T. Vorse. Mr. Vorse was a well-known architect of the time. He designed many Des Moines landmarks, including Court Avenue Bridge, Des Moines Municipal Courthouse (now the home of Des Moines Police Department) and Hoyt-Sherman Auditorium.

The Infiltration Gallery provided all the water to the Des Moines area until 1949. Increased water demand required construction of an intake on the Raccoon River in 1949, and the drought of 1977 precipitated construction of an intake on the Des Moines River in 1980. Today, the Infiltration Gallery system provides the first 20 million gallons of water each day, and a century later, the flooding station is still in use.

Posted by: Laura Sarcone No Comments
Labels: , , Posted in About Us, Infrastructure, Source Water