Archive for February, 2018

February 13, 2018

Exploring Variations in Water Quality Parameters in the Raccoon River

Rivers are incredibly dynamic ecosystems. To paraphrase the Greek philosopher Heraclitus, no one ever steps into the same river twice, because it’s not the same river nor the same person. A team of scientists from Drake University has been investigating changes in the Raccoon River at various locations over an 18-month period.

“The goal of our work is to understand the patterns of the Raccoon River across space and time,” said Peter Levi, a faculty member in Drake University’s Department of Environmental Science and Sustainability.

Every two or three weeks since June 2016, Levi and several students from Drake visit nine sites in the South, Middle, North, and mainstem Raccoon River. The sampling sites are bridges and boat ramps – from Minburn and Redfield to downtown Des Moines

Levi and his team have been focused on several key parameters that are important metrics of water quality: suspended sediment, nutrient concentrations in the water, and the rates of sediment denitrification (a natural microbial process that permanently removes nitrate from river water). Together, measuring these parameters at frequent intervals over an 18-month time period will allow the scientists to investigate the influence of seasonal changes and land-use on water quality in the lower Raccoon River watershed. The field component of the research will continue through December, but Levi has already seen interesting results.

“The different branches of the river fluctuate so much between each other on the same date and within the same branch across dates. It will be exciting to wrap up the fieldwork and start to analyze the patterns in relation to climate and landscape data.”

The research by Drake’s Stream Ecosystem Ecology Lab (SEEL) has been a community effort. Teams of citizen scientists were deployed to sample the Raccoon River at more points in July 2017. Three teams of volunteers covered over 80 river miles in just three days. The intensive sampling will provide the researchers an opportunity to understand how each branch varies at a much finer scale.

In August 2017, Des Moines Water Works agreed to provide Drake University analytical assistance for the monitoring project of the Raccoon River.  This laboratory support is provided at a reduced rate, saving Drake approximately $30,000.

“We appreciate Peter Levi’s work and Drake’s support of monitoring nutrient trends and natural denitrification rates in the Raccoon River,” said Bill Stowe, CEO and General Manager. “This project could be the start of a great partnership examining nutrients in our source waters.”

Posted by: Laura Sarcone No Comments
Labels: , , Posted in Source Water, Uncategorized, Water Quality February 1, 2018

Water Main Replacement Program

Water main replacement planning is a necessary, preventative approach that saves money on repairs, reduces the loss of water that occurs as a result of the main breaks, and minimizes disruption to customers.  Des Moines Water Works budgets for water main replacement to maintain and upgrade the distribution system by replacing water mains that have a history of breaks, to improve the fire flow, relocating to accommodate city, county, or state construction projects, and upgrading water mains to meet the needs of customers.

Several factors impact which water mains are replaced and the approach to planning for 2018 was different than in years past.  Des Moines Water Works’ Long Range Plan through 2040 included the analysis of water main break data occurring within the system.  Through this analysis, a relative risk score was created based on the assessment of consequence of  failure, likelihood of failure, and a capacity factor.  Pipe segments consisting of risk scores in the highest range are highly recommended for replacement.  Staff from various departments provided input while creating the priority list of streets for water main replacement.  Des Moines Water Works’ 5-year Capital Improvement Plan (CIP) includes approximately $7 million of water main replacement each year.  The City of Des Moines also has a 5-year CIP for city streets and sewers.  Des Moines Water Works and the City of Des Moines work collaboratively to choose the streets to be the most cost effective and cause the least disruption to customers.

After each project is designed, Des Moines Water Works will receive bids from contractors and the construction contract will be awarded to the contractor that will be performing the work.  If the bids received allow Des Moines Water Works to complete all the streets within budget, construction will take place in 2018.  Construction not completed in 2018 will take place in future years.  Des Moines Water Works is currently contacting customers directly in the neighborhoods throughout Des Moines and Polk County that have been scheduled for water main replacement in 2018.  Additional customer letters and public meetings will be forthcoming.  Des Moines Water Works appreciates the cooperation and understanding from customers during construction and will work with contractors to minimize the inconvenience to customers impacted by the following projects:

Polk County Water Main Replacement – CONTRACT 1

  • NE 14th Street from I-80/35 Westbound Off Ramp to NE 43rd Avenue

Des Moines Water Main Replacement – CONTRACT 1

  • Thomas Beck Road from Crown Colony Court to 1401 Thomas Beck Road
  • Fleur Drive from George Flagg Parkway to SW 22nd Street
  • Maple Street from E 2nd Street to E 4th Street
  • E 4th Street from Maple Street to Des Moines Street
  • Alternate Street – Watrous Avenue from SW 14th Street to Glover Avenue

Des Moines Water Main Replacement – CONTRACT 2

  • SW 9th Street from Johnson Street to Amos Avenue
  • SW 10th Place from Southdale Drive to County Line Road
  • SW 11th Street from Southdale Drive to County Line Road
  • SW 15th Street from Army Post Road to Johnson Street
  • Alternate Streets – SE 8th Street from E Miller Avenue to E Rose Avenue and Wall Avenue from SW 13th Place to SW 12th Street

Des Moines Water Main Replacement – CONTRACT 3

  • Kenyon Avenue from SW 16th Street to SW 9th Street
  • SE 14th Street from E Diehl Avenue to E Thornton Avenue
  • SE 14th Street from E Thornton Avenue to E Watrous Avenue
  • Alternate Street – Pioneer Road from SE 14th Street to 1603 Pioneer Road
Posted by: Laura Sarcone No Comments
Labels: , , , Posted in Customer Service, Customers, Infrastructure