Archive for the ‘Water Quality’ Category

January 7, 2015

Winter Source Water Problems

The United States Environmental Protection Agency (EPA) recently celebrated the 40th anniversary of the Safe Drinking Water Act (SDWA), which Congress passed on December 16, 1974, directing EPA to implement a series of regulations and standards to protect public drinking water from source to tap. The law was amended in 1986 and again in 1996 to include additional actions to protect drinking water, including those that recognize the needs for source water protection, training for water system operators, funding for water system improvements, and public information about the quality of treated water to inform water consumers and hold water delivery systems accountable.

Continued high nitrate levels in Des Moines Water Works’ source waters – the Des Moines and Raccoon Rivers – forced Des Moines Water Works to activate its nitrate removal facility early December 2014. On December 16, 2014, the 40th anniversary of the SDWA, the denitrification facility remained in use in order to ensure Des Moines Water Works’ finished drinking water was safe for consumption, as defined by the SDWA.

In addition, Des Moines Water Works was forced to use emergency water storage from Maffitt Reservoir at the L.D. McMullen Water Treatment Plant. Water at Maffitt Reservoir is considered emergency storage water for use during exceptional instances of water quantity and water quality. Use of the emergency water today, reduces the amount of storage water available for use during high customer demand periods.

“Des Moines Water Works staff has exercised extensive efforts to reduce nitrate levels to an acceptable level, as prescribed by the United States Environmental Protection Agency,” said Bill Stowe, CEO and General Manager, Des Moines Water Works. “Because nitrate continues to be introduced in the watershed at high levels, we are forced to use emergency storage water, in addition to running the nitrate removal facility, in order to maintain delivery of safe drinking water to our customers.”

The EPA’s maximum contaminant level (MCL) for nitrate in finished drinking water is 10 mg/L.  The levels seen in the Raccoon and Des Moines Rivers last fall and this winter are unprecedented for this time of the year. The monthly averages are as follows:

 

Raccoon River               Des Moines River

September 2014           11.89 mg/L                          7.20 mg/L

October 2014                 13.23 mg/L                         11.15 mg/L

November 2014           13.43 mg/L                         11.96 mg/L

December 2014            12.56 mg/L                         11.14 mg/L                  

Des Moines Water Works remains committed to fighting for cleaner source water on behalf of the 500,000 central Iowans Des Moines Water Works is pleased to serve.

According to the Iowa Nutrient Reduction Strategy, approximately 92% of nitrate loads enter our water resources through agricultural sources that are not currently being subject to any mandatory regulations, despite longstanding legal mandates to address such pollution.

“While Des Moines Water Works continues to incur costs and reduce available water storage, polluters of the watershed are not regulated,” said Stowe. “This is a public health issue for our customers. We cannot continue to meet the increasing water demand of our customers without regulation of pollutants in our source water.”

In order to ensure that tap water is safe to drink, the EPA prescribes regulations limiting the amount of nitrate levels in water provided by public water systems. The greatest health risk posed by high nitrate concentrations is for infants under six months of age. Nitrate can transform into nitrite in the infant’s body, reducing the ability of the baby’s blood to carry oxygen. This may result in Blue Baby Syndrome. Des Moines Water Works’ finished drinking water nitrate concentration is currently below the level which is indicated to cause these health implications.  If you are caring for an infant, you may wish to seek advice from your healthcare provider.

Despite the high levels of nitrate in the source waters, Des Moines Water Works’ finished drinking water remains safe for consumption.

Posted by: Laura Sarcone No Comments
Labels: , , , , , , Posted in About Us, Source Water, Water Quality December 4, 2014

Des Moines Water Works Forced to Start the Nitrate Removal Facility

Nitrate Removal FacilityContinued high nitrate levels in the Des Moines and Raccoon Rivers have forced Des Moines Water Works to activate its nitrate removal facility in order to keep finished drinking water safe for consumption. Nitrate levels in September, October and November were the highest ever experienced in those months and have required extraordinary efforts by Des Moines Water Works staff.  Activation of the nitrate removal facility is the last step available to maintain safe drinking water.

Current nitrate levels are 12.62 milligrams per liter (mg/L) in the Raccoon River and 11.63 mg/L in the Des Moines River. By means of extensive and expensive water treatment, Des Moines Water Works’ finished drinking water currently has a nitrate level of 8.79 mg/L. The Environmental Protection Agency’s (EPA) maximum contaminant level (MCL) for nitrate in finished drinking water is 10 mg/L.  Despite the high levels of nitrate in the source waters, Des Moines Water Works’ finished drinking water remains safe for consumption, due to the activation and operation of the costly nitrate removal facility.

Des Moines Water Works began using the nitrate removal facility today to keep finished drinking water nitrate levels below the Safe Drinking Water standard. Prior to starting up the facility, Des Moines Water Works staff managed the fall/early winter high nitrate situation through blending of various water sources, including water from the gallery system at the Fleur Drive Treatment Plant (shallow ground water collector system), Maffitt Reservoir, Crystal Lake and Aquifer Storage and Recovery (ASR) wells.

“Des Moines Water Works staff has employed extensive efforts to mitigate nitrate levels, but because nitrate continues to be introduced in the watershed at high levels, we were left with no alternative but to activate the nitrate removal facility,” said Bill Stowe, CEO and General Manager, Des Moines Water Works.

According to the Iowa Nutrient Reduction Strategy, approximately 92% of nitrate loads enter our water resources through sources that are not currently being subject to any mandatory regulations, despite longstanding legal mandates to address such pollution.

“Continued but unfounded insistence from state leaders that the voluntary approach of the Iowa Nutrient Reduction Strategy is working does not give solace to the 500,000 central Iowans who must now pay to remove pollution from their drinking water,” said Stowe. “Further, the persistent argument that ‘weather is to blame’ for this situation is wrong.  Science proves weather and other natural conditions do not create excessive nitrate concentrations. Intensive land use and extensive agricultural drainage systems are the source of the high nitrate in our source waters.”

Raccoon River               Des Moines River

September 2014           11.61 mg/L                          7.20 mg/L

October 2014                 13.23 mg/L                         11.15 mg/L

November 2014           13.25 mg/L                         11.88 mg/L

Record nitrate levels were reached in 2013, when the Raccoon River reported 24 mg/L and the Des Moines River reported 17.87 mg/L. Throughout the spring and summer of 2013, Des Moines Water Works operated the nitrate removal facility for 74 days, at approximately $900,000 in treatment costs and lost revenues passed on to ratepayers.

In order to ensure that tap water is safe to drink, the EPA prescribes regulations limiting the amount of nitrate levels in water provided by public water systems. The greatest health risk posed by high nitrate concentrations is for infants under six months of age. Nitrate can transform into nitrite in the infant’s body, reducing the ability of the baby’s blood to carry oxygen. This may result in Blue Baby Syndrome. Des Moines Water Works’ finished drinking water nitrate concentration is currently below the level which is indicated to cause these health implications.  If you are caring for an infant, you may wish to seek advice from your healthcare provider.

Posted by: Laura Sarcone 1 Comment
Labels: , , , , , Posted in Source Water, Water Quality December 1, 2014

Understanding Water Quality Warnings

Des Moines Water Works constantly strives to maintain water quality and safety throughout the distribution system. In certain situations, such as major water main breaks, quality of water in the system can become compromised. In these situations, Des Moines Water Works may issue a boil advisory or a boil order. Des Moines Water Works will notify customers within the affected area via the Code RED emergency notification system, and the media, as necessary.

Similar to severe weather threats, it’s important to understand the meaning of the water quality warnings.

A boil advisory (think of a tornado watch) is a precautionary measure issued in situations where a water main break or a large demand such as a fire has created low pressure in the distribution system, but there is no reason to believe water quality has been compromised. In these situations, as a precaution, customers are encouraged to boil water that will be consumed or used for food preparation. Water should be boiled for two minutes and allowed to cool before use.

A boil order (think of a tornado warning) is issued in a situation, such as a major water main break, where there is significant potential for the quality of the water in the distribution system to be compromised. In these situations it is essential that customers boil all water that will be consumed or used for food preparation. Water should be boiled for two minutes and allowed to cool before use. This includes water used for: drinking water (including pets), brushing teeth, baby formula, preparing food, washing produce, and preparing coffee, tea, lemonade, etc. Water is safe to use for showering; however, be careful not to ingest the water. Water used for laundry, general washing and outdoor use is safe to use without boiling.

To ensure the quality and safety of the water has been restored following a boil order or boil advisory, Des Moines Water Works must perform analyses on two samples from the area, one taken immediately following the issue and one taken 24 hours later. This means a boil advisory or boil order will be in effect for at least 48 hours. Des Moines Water Works will communicate the end to the order or advisory to give customers an “all clear” signal, at which time customers can be confident the water is safe to drink. While these situations are rare, Des Moines Water Works understands boil advisories and boil orders are an inconvenience to our customers; however, there are no compromises when protecting the health of you and your family.

Stay informed: sign up for the Polk County’s Code Red emergency notification system at https://public.coderedweb.com/CNE/33A099CF3F14. Follow us on Facebook and Twitter. During a major emergency, we will also confirm information and provide details at www.dmww.com.

Posted by: Laura Sarcone No Comments
Labels: , , , , , Posted in Water Quality November 24, 2014

Investment in Aging Water Infrastructure and Degraded Source Water

PumpsIn setting water rates and the proposed budget for 2015, the Board of Water Works Trustees has demonstrated a continued commitment to investing in Des Moines’ aging water infrastructure and providing safe water to customers, despite increasingly poor quality of source waters.

“While Des Moines Water Works has a long history of substantial reinvestment in water infrastructure, the aging of our assets and our increasing concerns about the impacts of climate change requires even greater investment going forward,” said Bill Stowe, Des Moines Water Works CEO and General Manager. “The degradation of our infrastructure is evidenced by the increasing number of main breaks, and affects our mission to provide a quality and reliable service to our customers.”

The Board of Water Works Trustees believe in a funding philosophy of “pay as you go,” where improvements and replacements are funded through rates and not funded by debt, all while maintaining reasonable water rates in relation to the rest of the country.

The proposed Des Moines Water Works’ 2015 calendar year budget includes rate increases for Des Moines, total service, and wholesale water customers. The rate increases include a 7% increase for Des Moines and total service customers and a 5% increase for wholesale customers, namely suburban customers who purchase water from Des Moines Water Works to resell to their residents. The 7% rate increase is only for the water portion of the monthly bill, not city services that Des Moines Water Works collects for city agencies. For a typical four-person household inside the city of Des Moines, the 7% increase equates to an additional $1.65 on a customer’s monthly water bill.

Certain service areas, such as unincorporated Polk County, have greater capital needs to combat an aging system and accommodate growth. Beyond a 7% increase in rates, those customers will have an additional $1.50/thousand gallon fee that will fund significant capital improvements in the service area.

The 7% increase for Des Moines customers is fundamental to supporting operations and a healthy capital reinvestment program, including facilities necessary to adequately treat source waters that continue to degrade.

“Delivering safe and reliable water to our customers is a capital intensive responsibility,” said Stowe. “Even while working efficiently, the costs for treatment and distribution of water continue to rise. To not invest in critical water infrastructure and capital improvement projects would be irresponsible.”

In addition to investment in the aging infrastructure, the 2015 rates reflect the nearly $1 million Des Moines Water Works spent in 2013 to reduce nitrate concentrations found in Des Moines Water Works’ source waters to a level below the U.S. Environmental Protection Agency’s safe drinking water standard.

Within the proposed 2015 budget, 16% of the utility’s capital budget will be spent on improvements to naturally reduce rising nitrate levels in source waters. This includes the use of sand quarries and gravel pits that naturally filter nitrate – a longer term investment and more cost effective solution in comparison to operating and expanding the expensive nitrate removal facility.

New water rates will go into effect April 1, 2015. A complete listing of Des Moines Water Works’ 2015 water rate structure is available at www.dmww.com/upl/documents/library/2015-water-rates.pdf.

Posted by: Laura Sarcone No Comments
Labels: , , , , Posted in Infrastructure, Rates, Value of Water, Water Quality October 6, 2014

Your Comments Needed for the Waters of the U.S. Rule

One in three Americans gets their drinking water from rivers and streams that are vulnerable or impaired, including the 500,000 central Iowans who depend on the Raccoon and Des Moines Rivers as the source of their drinking water.

Iowans must speak out and demand clean water in our rivers that is essential for drinking, swimming, and fishing. Clean water is critical to viable communities and economic growth. Sixty percent of streams and millions of acres of wetlands across the country are not clearly protected from pollution and destruction.

Over 40 years ago, Congress passed the Clean Water Act. The focus was to, through regulatory means, remove raw sewage and industrial pollution from rivers and lakes. Thanks to cleanup efforts spurred by the Clean Water Act, the pollution from these sources has decreased immensely or been eliminated.  Unfortunately, agriculture was exempt from most provisions of the Clean Water Act, and today, is the largest contributor to water pollution in Iowa’s rivers and the country. It is time to expand the Clean Water Act regulations to include all sources of pollution – including agriculture.

The U.S. Environmental Protection Agency and the U.S. Army Corps of Engineers have proposed stronger protections for the clean water vital to all Americans, but agriculture continues to be exempted. The proposal is the Clean Water Act-Waters of the United States rule. Agriculture exemptions have degraded Iowa’s rivers and lakes and should no longer be allowed. Iowans must engage in protecting water resources by demanding the support of Iowa’s congressional delegates and state legislators to expand regulations in the Clean Water Act to include sources of agricultural pollution.

The current EPA-Corp of Engineers proposed rule is open for public comment until October 20, 2014. Do your part to support the current proposal, but also ask for expansion of the Clean Water Act to include agricultural sources of pollution. Your drinking water, your health, the ability to fish and swim in Iowa rivers and lakes, and the economic viability of our communities is dependent on your actions today. Future generations are depending on you. Submit your comments at: www.epa.gov/uswaters.

For additional information:

Posted by: Linda Kinman 1 Comment
Labels: , , , , , Posted in Source Water, Water Quality September 30, 2014

Middle School Students, EPA Region 7 Administrator Talk Water Quality

DSC_0452EPA Region 7 Administrator Karl Brooks will be in Des Moines, Iowa, on Friday, Oct. 3, to visit with Brody Middle School seventh grade students about EPA’s role in protecting water quality. Brooks’ visit will include a role-play exercise featuring six groups of students representing EPA, scientists, farmers, concerned citizens, Des Moines Water Works, and non-profits. Afterwards, a group of students will participate in a water quality testing exercise at Des Moines Water Works Park.

Brooks will discuss the importance of EPA’s partnerships to protect water quality in Iowa, and the Waters of the U.S. proposal. EPA and the U.S. Army Corps of Engineers released a draft proposal in March to strengthen protection for the clean water that is vital to all Americans.

The students are learning about Iowans’ water pollution reduction efforts, Iowa’s nutrient reduction strategy, and best management agricultural practices to improve water quality.

Brody Middle School serves about 780 sixth-, seventh- and eighth-grade students within the Des Moines Public School District.  Brody is an International Baccalaureate candidate school where learning is incorporated with an understanding of how individuals fit into the world and how their actions affect others.  Approximately 120 seventh graders have been learning about water quality at Brody.

The Des Moines metropolitan area’s 500,000 residents receive their drinking water from Des Moines Water Works, which draws water from the Raccoon and Des Moines rivers. The quality of these rivers is fundamental to providing safe drinking water for the public health of the Des Moines community.

  • WHO: Karl Brooks, EPA Region 7 Administrator
  • WHAT: Remarks, role-play student exercise and students learning about water chemistry (all events are open to the press).
  • WHEN: Friday, Oct. 3, 2014, 1:00 p.m. to 1:45 p.m., Brooks’ remarks and activity at Brody Middle School; 2:15 p.m. to 2:45 p.m., Water quality testing at Des Moines Water Works Park.
  • WHERE: Brody Middle School, 2501 Park Avenue, Des Moines, Iowa 50321 and Des Moines Water Works Park, 412 Fleur Drive, Des Moines, Iowa 50321. After entering the park, watch for signage to the pond.

Clean water is important for drinking, swimming, farming, fishing, businesses and communities.  Sixty percent of streams and millions of acres of wetlands across the country aren’t clearly protected from pollution and destruction. One in three Americans—117 million of us—get our drinking water from streams that are vulnerable.

To help celebrate October as Children’s Health Month, EPA works with parents, teachers, and health providers to promote environmental education and healthy environments for children. EPA recognizes the importance of educators’ in incorporating environmental education in their classrooms and teaching methods.

Posted by: Laura Sarcone No Comments
Labels: , , , , , , , , Posted in Source Water, Water Quality August 18, 2014

Water Quality Mystery

It is no mystery as to why water quality in Iowa must be improved. The mystery is why major efforts to improve water quality are not moving forward with the urgency Iowans should demand.

The toxic cyanobacteria bloom in Lake Erie that shut down the water supply for nearly half a million residents in Toledo, Ohio for several days earlier this month has highlighted the importance of watershed protection.

Much like Toledo, cyanobacteria is prevalent in Iowa. Bill Stowe, CEO and General Manager of Des Moines Water Works, said “it’s not a matter of if, but a matter of when,” Des Moines could face a similar problem.

state beach closed by DNR

Frequently, we hear on local news stations that the Iowa Department of Natural Resources has issued a beach advisory, which can be due to bacteria or microcystin (toxin from cyanobacteria) levels. Both cyanobacteria and algae growth are in response to warm weather and nutrients (i.e. nitrogen and phosphorus) from agricultural practices, and can proliferate in the source water to a degree that affects water treatment operations.

On August 7, 2014, “Swimming not Recommended” advisories due to high levels of bacteria were posted by Iowa DNR at the following state beaches:

  • Blue Lake Beach at Lewis & Clark State Park
  • Denison Beach at Black Hawk State Park
  • Prairie Rose Beach at Prairie Rose State Park
  • Lake of Three Fires at Lake of Three Fires State Park
  • Beed’s Lake Beach at Beed’s Lake State Park
  • Union Grove Beach at Union Grove State Park
  • Backbone Beach at Backbone State Park
  • Lake Keomah Beach at Lake Keomah State Park
  • Geode Lake Beach at Geode State Park

The number of microcystin advisories at state beaches has increased each year.

Year      Number of Microcystin Advisories

2014       11 (through week 11 of a 15-week season)

2013       24

2012       14

2011       7

Swimming advisories are issued between Memorial Day and Labor Day each year. The advisories are posted when bacteria or microcystin levels are determined to be a risk for swimming and/or potential ingestion of contaminated water. For up to date information, call the DNR Beach Monitoring Hotline at (319) 353-2613. Information is also posted at http://www.iowadnr.gov/Recreation/BeachMonitoring.

The “do not drink” incident in Toledo is a reminder that the protection of our source waters is critical to the protection of public health. This should be a call to action for citizens to advocate for cleaner source water and to question the current rhetoric on voluntary agriculture conservation practices.

The benefits of hearing about water quality issues and concerns first hand from the public are invaluable to local and state government leaders. The Governor, agency directors, legislators and local city council members need to hear from you about your experiences and perceptions of the quality of water in Iowa’s rivers, streams and lakes. When citizen outcry is sufficient, and actions are transparent and measured, we will be able to take the next step to improving Iowa’s quality of life.

Posted by: Linda Kinman No Comments
Labels: , , , , , , Posted in Source Water, Water Quality August 6, 2014

Toledo’s “Do Not Drink” Order Should be a Wake-up Call

Toledo glass of algaeLast weekend, the City of Toledo advised its customers against drinking the city’s tap water. The municipal ban left 500,000 Toledo and Michigan residents without drinking water for three days, which was contaminated by a toxin produced by an algae bloom in Lake Erie.

Cyanobacteria, commonly referred to as blue-green algae, are a serious problem in surface water sources in the United States. In drinking water, they are most commonly known for causing taste and odor problems.  In some cases they can also release cyanotoxins, which raise health concerns related to the liver, nervous system and gastrointestinal system.

In Toledo, a cyanobacteria bloom is an annual occurrence and was recently quite visible near Toledo’s water intake system on Lake Erie. Tests last week from the city’s water treatment plant confirmed the detection of microcystin — a cyanotoxin produced by the harmful blue-green algae. City officials were told by the Ohio Environmental Protection Agency to issue a “do not drink” order for its entire population.

The cause of the annual cyanobacteria bloom in Toledo is primarily phosphorus from farm fertilizer runoff, and the amount of phosphorus determines the bloom’s size. Scientists are also learning that another farm fertilizer, nitrogen, affects the size and composition of the annual bloom.

The “do not drink” incident in Toledo is a reminder that the protection of our source waters is critical to the protection of public health.

Much like Toledo, cyanobacteria is prevalent in Iowa. At Des Moines Water Works, phytoplankton studies are performed on Des Moines’ sources waters – the Raccoon and Des Moines Rivers. Cyanobacterial and algal counts comprise the phytoplankton studies.  These studies determine the numbers and species of the most common phytoplankton viewed microscopically.

Blue-green algae bloom at Big Creek

 

Both cyanobacteria and algae grow in response to warm weather and nutrients (i.e. nitrogen and phosphorus), and can proliferate in the source water to a degree that affects water treatment operations.

Des Moines Water Works staff treats for unfavorable tastes, odors, and toxins by dispersing powdered activated carbon throughout the water (much like when water is ran through a carbon filter).  Chlorination of the water also helps remove or destroy bad tastes, odors, and cyanotoxins.

When the phytoplankton counts become high, Des Moines Water Works staff can respond by switching from one river to the other, by maximizing use of the infiltration gallery system (a series of underground pipes located throughout Water Works Park next to the Raccoon River), and by using water stored in aquifer storage reservoirs or water produced at the L. D. McMullen and Saylorville Water Treatment Plants.

Currently there is not a federal standard for blue-green algae or their toxins in drinking water; however, a growing number of states are introducing their own guidelines and the U.S. Environmental Protection Agency has named cyanotoxins as a candidate for federal regulation.

Strategic water treatment, testing, and federal regulation of cyanotoxins are worthy, but a remedy at the source of the contaminant is more urgent. The only viable option to curtail the presence of algae that can potentially cause toxins to infiltrate our drinking water is changing upstream land practices.

Creating buffers, like plants and trees that stand between farms and the water, may help catch fertilizer chemicals before they get into water ways, spurring algae growth. Farmers could also, theoretically, use less fertilizer, though there are no regulations in place as of now.

Farm runoff is not very regulated, so the drinking water contamination incidence in Toledo could happen again, and here in Iowa.

This should be a call to action for citizens to advocate for cleaner source water and to question if voluntary water protection measures work.

 

Top photo credit: A glass of algae filled Lake Erie water, near the Toledo water intake crib, on Sunday via The Toledo Blade.

 

Posted by: Laura Sarcone No Comments
Labels: , , , , , , Posted in Source Water, Water Quality, Water Treatment July 16, 2014

Des Moines Waterways Snapshot

Cool streams on hot summer days draw children like a magnet.  Children are out of school and seeking adventure.  They see streams as an opportunity to explore, looking for stream critters or perhaps simply to cool off by wading in shallow water.

They are typically less aware of the potential physical, biological, and chemical hazards from runoff, failing septic systems, and broken sewer pipes.  So what is the condition of our urban streams?  Are they healthy and safe or simply storm sewer waterways to quickly discharge contaminated water to the major rivers?  Approximately 25 volunteers, together with staff from the Iowa DNR, have sought to answer these questions.

Polk County SnapshotThe Polk County Snapshot volunteers go out on a designated day in the spring and fall, rain or shine, to perform field analyses, collect samples, and make field observations of the physical characteristics of the water and look for exposed or damaged pipes.  They have been doing this since 2004, routinely collecting samples from 30 sites throughout the metro area to answer water quality observations.

The most recent snapshot was taken in May. The good news is that there is little evidence of direct fecal contamination from broken sewer, despite the more than a thousand miles of sewer pipe.  There is little difference in fecal bacteria levels between rural and urban streams.  During rainy weather with runoff, bacteria levels get very high in both urban and rural streams.  During hot dry weather (when children most likely are exploring streams) bacteria levels are low (sewage from broken pipes would cause very high levels of bacteria during low stream flow because of less dilution by stream flow).  Occasional high bacteria levels were observed in locations where yard wastes were raked into the stream.  It is probable that pet droppings were included with the leaves. Urban streams differ slightly from rural streams following a small shower. In urban areas, roofs and streets create runoff to storm sewers and elevated bacteria levels in the stream while a light rain in rural area soaks into the ground with little runoff to carry fecal matter to the streams.  During heavy rain, rural streams generally had higher bacteria levels.  Livestock wastes are essentially untreated and often applied on the ground and not incorporated to reduce loss from runoff.

Nitrate and phosphorus concentrations are usually higher in rural streams.  Exceptions occur during dry weather below the outfall from wastewater treatment plants.  The concentrations decrease downstream because of dilution and biological activity including algae growth.  Bacteria levels at these sites were low, indicating good biological treatment. Very high chloride concentrations (up to 10 times normal conditions) occurred at sites in the spring that implicated road salt as the source.

Arguably, the biggest threat to stream quality and public safety is flash flooding following a heavy rain.  Storm sewers are designed to drain water from streets as quickly as possible.  This greatly increases erosion leading to bank instability and a scouring of the stream bed.   Redesigning storm water discharge structures and the creation of greenways should reduce this threat, improve habitat, and reduce erosion.  Continued observations and stream monitoring will help determine the effectiveness of these activities.

We applaud the diligence of the stream guardians in protecting our urban streams, making them safer, healthier, and more attractive.

Posted by: Gordon Brand No Comments
Labels: , , , , , Posted in Source Water, Water Quality June 27, 2014

What’s that Foam on the River?

With recent, heavy rains, all eyes are on the metro area’s rivers. With the water so high and visible, you may have recently noticed the foam floating on top of the Raccoon River. It may look like there was an upstream truck spill carrying dish detergent, but in fact, it is not soap causing the foam you are seeing on the river.

Detergents can produce foam, but usually the foam caused by detergents is white. The light tan foam recently seen in the Raccoon River typically occurs when decaying organic matter enters the water or is washed into the rivers and streams and begins to decay.  This forms soap-like molecules that are attracted to water on one end and oily substances on the other end.  The attraction of these substances to water reduces the surface tension on water.  Surface tension of water creates the “skin” on the surface of water that allows water strider insects to skate across the surface of the water and not sink.  When this skin becomes weaker, wind and turbulent water can easily break this skin.  The soap-like molecules (surfactants) hold onto fats and oils on one side and water on the other with air trapped inside.  The stronger the soap and water layer, the larger and more stable the bubbles.  Eventually, bacteria break down these substances so they can no longer form bubbles.

DSC_2835When living things die and decay, cells breakup.  This occurs in the alimentary tract (the tubular passage extending from the mouth to the anus, through which food is passed and digested) of animals and is eliminated with the fecal matter. Therefore, a high concentration of this waste contributes to the formation of the foam you are seeing on the Raccoon River right now.  This can come from poorly operated waste treatment facilities and untreated animal waste.

Testing at Des Moines Water Works’ laboratory shows low phosphorus concentrations, indicating the foam to be from the decay of natural vegetation and waste products, rather than from direct human activity. Des Moines Water Works monitors its source waters daily for contaminants to determine which source to use and how to best treat the water in order to provide safe and clean drinking water to its customers.

Posted by: Gordon Brand No Comments
Labels: , , , , , Posted in Source Water, Water Quality