LOCAL

Ever wondered why foam rises in the Concho River after it rains? Here's why

Samuel Sutton
San Angelo
Foam rises in the Concho River after heavy rainfall Wednesday, April 24, 2019.

SAN ANGELO — Ever wondered why the heck the Concho River gets so foamy after it rains? We've got the answer.

Shannon McMillan, stormwater program administrator for the City of San Angelo, gave several reasons as to why foam could rise in the river. Below is a list of reasons.

Read more:Here are overnight rainfall totals, what to expect for San Angelo Wednesday

Foam is compacted in a corner on the Concho River after heavy rainfall Wednesday, April 24, 2019.

What causes foam in the Concho River?

  • Organic material: McMillan said the primary reason is that leaves, branches and other organic materials release natural surfactants and breakdown in the water creating foam.
  • Bacteria: Pets and other types of animals often mingle and do their business in the river, which can cause bacteria in the river. This is another foam contributor.
  • Chemicals: Things like industrial detergents and dye can cause a lot of foam.  In 2007 or 2008 — before McMillan's time with the City — she was told about a report that was made of foam in the river. Upon further investigation, they discovered dye in the river. They have since cleaned all of that out.
Foam rises after rainfall in the Concho River Wednesday, April 24, 2019.

City's work in preventing contamination.

If the foam goes away relatively quickly, McMillan it usually means it was due to organic material.

McMillan said the Stormwater Department collects storm runoff before it gets to the river to check for water-quality parameters that are indicative of water-quality issues. They test for suspended solids, phosphates, nitrate/nitrite and biochemical oxygen demand. Other indicators they look for include smells, sheen and color.

If a parameter is above action levels, they start working to figure out what caused it. If it is found that a person was the contributor, they will do source tracking to determine if it's from a specific site.

Read more:City of San Angelo seeks state funding for Hickory water project

Do your part, don't contaminate the river.

McMillan offered several ways residents can help reduce and prevent contamination.

  • Clean up after your pets
  • Don't litter
  • Partake in responsible yard maintenance.

Remember, blowing cut grass into the gutters is prohibited, as it could cause contamination.

If a resident sees something concerning, McMillan asks for them to report a violation by calling 325-486-3780 or by emailing stormwater@cosatx.us.

Samuel Sutton is a multimedia journalist for GoSanAngelo.com. If you have a news tip, either send it to Samuel.Sutton@gosanangelo.com or News@gosanangelo.com, or call 325-812-7179.