Posts Tagged ‘Source Water’

August 11, 2011

What’s In the (Source) Water?

Ignorance can be bliss, but most of us would like to be informed about what we are drinking.  For this reason, Des Moines Water Works (DMWW) makes a conscientious effort to share with our customers all of the details pertaining to their drinking water system. Sometimes, the news isn’t always good!

E. coli is a species of bacteria found in the intestinal tract of vertebrates. DMWW lab staff regularly looks for them in our source waters and in our treated drinking water.  E. coli is used as an indicator that water is potentially contaminated with human and animal waste, and therefore possible disease organisms.  Not even one E. coli bacterium can legally be present in drinking water, according to the Environmental Protection Agency (EPA) standards.  The numbers in source water can vary from zero to an amazingly high number in both the Raccoon and Des Moines Rivers. Des Moines Water Works relies heavily upon these two rivers as sources for fulfilling the Metro area’s daily demand for water. E. coli values over 2 million colonies/100 millimeter are present at times in some of the smaller streams that feed into our rivers.

DMWW’s extensive and rigorous treatment process physically removes or kills all of these bacteria before the water is delivered to customers.  Nonetheless, customers should be aware of the water quality present in Iowa’s water resources, which are the source of drinking water for the state’s residents.

Posted by: Laura Sarcone No Comments
Labels: , , , , , , Posted in Water Quality, Water Treatment June 2, 2011

2011 Legislative Wrap-up

At this time of year the legislators have generally wrapped up the state’s business and gone home.  But 2011 finds them still haggling over the budget. Cuts in budget appropriations for the Departments of Agriculture and Land Stewardship (IDALS) and Natural Resources (DNR)  could have potential impacts on the drinking water industry and the protection of water resources treated for drinking water.

The IDALS/DNR appropriation is less than 1% of the total state budget, yet they continue to experience severe budget cuts.  These cuts will negatively impact services provided and increase the amount of response time to provide those services.  Last year 63% of Iowa voters told legislators they wanted more money spent on the protection of Iowa’s water, land, and air resources (I Will Campaign).  Instead, budgets for both departments have been cut again.  Ramifications of the appropriation budget cuts could: 

  • Potentially increase fees paid by all Iowa drinking water utilities
  • Delay flood plain mapping
  • Delay evaluation of Iowa’s groundwater aquifers to project and ensure future water availability
  • Reduce lake and ambient stream water quality sampling
  • Reduce siting assistance and enforcement of livestock facility regulations
  • Curtail watershed projects in the Des Moines and Raccoon River watersheds

Surface and ground water resources and drinking water infrastructure are owned by you, as a citizen of Iowa.  You have charged the state (the governor and legislature) with improving and protecting Iowa’s water resources.  You have charged each utility with the maintenance and protection of its infrastructure.  Continued budget cuts and the lack of political will in discussing and acting on water quality and quantity issues needs to be addressed.  Advocacy as a citizen is a powerful tool.  Use it to ensure that your infrastructure and abundant water resources are improved and protected for future generations.

Posted by: Linda Kinman No Comments
Labels: , , , , Posted in Water Quality February 10, 2011

Des Moines’ Water Quality

Des Moines Water Works uses the Raccoon and Des Moines Rivers as its source supply. How does water quality in these two rivers compare to that found in other parts of the United States?

Water from our rivers is “hard,” meaning it has a high mineral content, especially calcium and magnesium. This is because 100 million years ago, what is now Iowa, was under the surface of the ocean, and large limestone deposits are the result. As rain water and snow melt trickles through the limestone, toward shallow groundwater and eventually into our streams, it dissolves mineral deposits. Hardness is reduced in DMWW’s treatment plants using a process called lime softening.

The river water has a high nutrient content, especially nitrate-nitrogen and phosphorous. Some of the fertilizer used for crops is washed away or enters the streams through agricultural drainage tiles. Our super-rich soils also contain a lot of natural nitrogen and phosphorous, which is liberated from the soil during cultivation. The Raccoon and Des Moines Rivers have the highest and second-highest nitrate concentrations of the 42 largest Mississippi River tributaries. DMWW operates the world’s largest nitrate removal facility at its Fleur Drive Plant.

Our rivers have a relatively high level of sediment. Erosion is a natural process that has been greatly increased by both rural and urban land uses. It’s likely that most Iowa streams ran much clearer prior to settlement than in the present day. Loss of native perennial vegetation and increased streamflows because of human modification of natural hydrology, along with changes in land use and climate, are the primary culprits for increased erosion. In addition, levees have divorced streams from their floodplains, increasing river energy during high flows. This helps the stream scour sediment from the stream bed and banks. DMWW removes about 20,000 pounds of sediment (1,400 pounds per million gallons) from the treated river water every day, so the water will be clear and safe to drink.

Although DMWW’s source waters are considered impaired, DMWW is continuously adapting its treatment processes to deliver Water You Can Trust for Life.

Posted by: Chris Jones No Comments
Labels: , , , , , , , Posted in Water Quality, Water Treatment November 17, 2010

Know Your Watershed – Part 1

Watershed, catchment, and drainage basin are all the same thing: an area of land that drains to a common point. Small watersheds drain into larger watersheds in a hierarchical pattern. For example, the Mississippi River Watershed is comprised of hundreds of other smaller sub-watersheds.

The City of Des Moines is located at the bottom of two large catchments: the Raccoon and the Upper Des Moines River watersheds. These are two of the 42 largest sub-watersheds in the Mississippi River basin. Water draining from more than 5 million acres, from as far away as Jackson, MN, flows through the city. Des Moines Water Works treats water from both rivers to provide Des Moines Area residents with drinking water.

Knowledge of Iowa’s geological history and current land uses are necessary to understand each river and its water quality. Both the Raccoon and Des Moines Rivers flow through and drain the Des Moines Lobe Landform. It was here that a glacier covered the landscape only 12,000 years ago. The weather warmed and the disintegrating ice sheet formed the prairie pothole region that was once home to uncounted millions of waterfowl. After the glacier melted, the landscape was colonized by tallgrass prairie and wetland plants that helped form the region’s tremendously rich soil. The rivers ran clear and cold as rain water was naturally filtered through the perennial vegetation.

The early European settlers found the region nearly uninhabitable due to the swampy landscape and swarms of mosquitoes. A few decades after arrival, they realized that the soils formed under such conditions were ideal for the cultivation of corn. But first, large scale drainage was necessary. Networks of porous drainage pipes (now known as tile) were buried to lower the water table and dry out the soil. These were connected to constructed drainage ditches, essentially forming hundreds of new streams where none previously existed. This enormous project was mostly complete by 1920, although farmers continue to connect into and improve the system in the present day.

Constructed drainage and replacement of perennial vegetation with annual crops turned Iowa into the world’s richest agricultural region. But altering the natural hydrological system also had an impact on water quality in Iowa’s streams, this is will be discussed in the next piece in this series.

Posted by: Chris Jones No Comments
Labels: , , , , , , , , Posted in Water Quality