Protecting the Cahaba

What does protecting the Cahaba River have to do with how much you pay for wastewater service?

More than you might think.

In North Shelby County, we are blessed with an abundance of natural resources. One of the most important is the Cahaba River, our state’s largest free-flowing river and home to nearly 70 rare or imperiled plant and animal species.

As beneficiaries of this natural abundance, we all share a responsibility to protect and preserve it for our children and grandchildren.

The Birmingham metropolitan area is immensely enriched by the 140-mile-long Cahaba along with its tributaries and aquifer. It is therefore especially important that we maintain the quality of the millions of gallons of water we collectively take from and discharge into this vital river system each day.

Most recently The Environmental Protection Agency (EPA), and The Alabama Department of Environmental Management (ADEM) have ruled that excess amounts of phosphorus can lead to a significant reduction in water quality in the Cahaba River Basin, including such harmful effects as the uncontrolled growth of algae, dissolved oxygen deficiencies, and declines in wildlife and habitat. If allowed to go unaddressed, the higher phosphorus content in the river will also degrade fishing and boating activities and will impact tourism and property values.


Much of the phosphorus in the Cahaba and other rivers and streams can be traced back to stormwater runoff from lawns, farms and golf courses.

Because it would be difficult to monitor and regulate limits on thousands of privately owned areas where phosphates are applied, EPA and ADEM focus instead on already regulated “point sources” of phosphorus, including wastewater treatment facilities like the North Shelby Wastewater Treatment Plant (WWTP) that serves you.


Like over 20 other active wastewater treatment plants near the Cahaba, the North Shelby Plant (as it’s currently built) is simply not capable of meeting the new, lower limits. That is understandable when you consider that it was designed and built by Shelby County long before the new phosphorus limits were contemplated by EPA and ADEM.

As a direct result of the new EPA and ADEM environmental regulations regarding phosphorus, SouthWest Water Company has been required to construct an upgrade to the Plant that will help us treat and remove phosphorus.

As we shared with you last December, this will be a significant, multi-year effort involving the construction of new treatment processes.

We completed the initial design for the project in 2009, broke ground on its first phase in 2010 made good progress on the construction throughout 2011, and completed the work in 2012.

The new plant will enable us to meet the new, stricter treatment limits for phosphorus for the next several years, as required by EPA and ADEM.

In fact, we expect the new facility to reduce the amount of phosphorus we discharge to less than 0.2 parts per million. This represents a remarkable reduction of about 95% from current levels.


Construction of the required upgrade to the North Shelby Plant cost roughly $9 million. Largely as a result of this cost, it was necessary for us to raise user fees.

All fee adjustments have been reviewed and approved by the North Shelby Sewer Rate Review Board. The Rate Review Board was established by the Shelby County Commission as the oversight mechanism responsible for examining any annual adjustment to the monthly fee pursuant to the purchase agreement that governs the sewer system’s monthly rate.

Although we’ve gone to great lengths to contain the cost of this upgrade, we know it’s frustrating.

Meeting these new requirements from EPA and ADEM is imperative— both to ensure the treatment plant that serves you is in compliance and, moreover, to keep a cleaner Cahaba for all of us and the generations to come.

Please know that we will continue to do our best to provide you with dependable wastewater service at a fair price, while maintaining the quality of our vital waterways.


Photo: USFWS