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What will it take to get water quality and stormwater regulations to line up?

July 07, 2020

By Dan Edgerton

The drawbacks mount when fishable and swimmable get lost and mean something different to everyone

Last year, a colleague wrote a blog about the Environmental Protection Agency’s effort to create uniform standards for stormwater. I applaud this effort, because it is a first step at trying to address the inefficiencies that have mushroomed in stormwater regulations.

The most common complaints about stormwater regulations include adding unnecessary costs to public and private projects, and that they are all too often inconsistent, inefficient, and have a weak track record of achieving real water-quality improvements. 

Rainwater being pumped into a river from a storm retention pond.

Today’s stormwater regulations

The basis of much of our stormwater regulation is the 1972 Clean Water Act (CWA), which calls for eliminating the discharge of pollutants into the nation’s waters and achieving water quality levels that are fishable and swimmable. The initial focus of the CWA was untreated discharges from municipal and industrial sources. It resulted in the financing of sewage treatment facilities around the country, which led to a huge reduction of pollutant discharges and improvements to water quality.

In 2003, Phase II of the National Pollutant Discharge Elimination System (NPDES) Storm Water Program extended the CWA to cover nonpoint sources of pollution—primarily stormwater discharges from municipal and industrial sources. This underlies much of our current stormwater regulations.

One key aspect of the program is the goal of making all waters fishable and swimmable. While laudable in concept, this goal doesn’t consider that many waters are extremely difficult and expensive to make swimmable. Rather than focusing solely on the “low-hanging fruit” (waters that can more readily be cleaned up), regulators feel their hands are tied by the CWA to address all waters. This has resulted in regulations that require municipalities, developers, and businesses to spend massive amounts of money trying to protect receiving waters that have little hope of being swimmable.

Additionally, the CWA calls for states to implement programs to regulate and manage water quality. This has led to multiple entities taking on stormwater regulatory roles. They address not only water quality but stormwater peak rate control as well.

No one questions the value of good water quality. It’s essential for our health and quality of life.

Consider my local Twin Cities metro area. Stormwater is regulated by the Minnesota Pollution Control Agency, individual cities, and various watershed management organizations that cover the metro area. At times, other state agencies (Department of Natural Resources, Board of Water and Soil Resources, Department of Health) and the U.S. Army Corps of Engineers also get involved. Each has its own regulations covering applicability, submittal requirements, and design standards. While they all tend to be variations on a theme, no two are identical. Here are examples:

  • Peak runoff rate control: Most cover peak runoff rate control, generally limiting peak rates to existing conditions for the 2-year, 10-year, and 100-year storms. Some use the 1-year rather than the 2-year. Most use the NOAA Atlas 14 rainfall totals and distributions; others use the old TP-40 rainfalls. Some require control of the 100-year, 10-day snowmelt runoff event. Freeboard requirements (vertical distance from the 100-year high water level to adjacent structures and roadways) also vary—most use 2 feet, while others use 3 feet; some define the adjacent structure elevation by the low floor, while others use the low opening (for example, a basement window).
  • Stormwater quality treatment: Most cover stormwater quality treatment. Here it gets even more complicated. Some require pollutant removal efficiencies, others effluent loadings (e.g., pounds per day of phosphorus released), and still others the sizing of ponds or treatment basins. Some specify allowable water-quality models for estimating pollutant removals; others have created their own spreadsheet models.
  • Stormwater runoff volume: Finally, some also address stormwater runoff volume reductions. Here, you’re required to capture the first amount of rainfall on the site. Some require the first 0.5 inch of rainfall; others require 1, 1.1, or 1.4 inches. Infiltration of this rainfall is the desired treatment. However, much of the Twin Cities is underlain by clay soils that are not suitable for infiltration. This leads to “alternative sequencing,” as it is called, which usually entails a host of other options, including filtration, conservation areas, rain gardens, rainwater harvesting for irrigation, and others, often with a multiplication factor to reflect the fact that these aren’t as good as infiltration.

The programs and agencies that regulate stormwater and runoff vary based on state and local government mandates.

How effective are the stormwater regulations?

The real kicker, though, is that no one really knows how well these regulations work.

There is minimal rigorous monitoring of the thousands of stormwater quality features that have been installed in the Twin Cities. And what we have paints an uneven picture of their effectiveness. Some rain gardens remove phosphorus from stormwater; others act as phosphorus sources. Stormwater ponds are releasing phosphorus from collected sediment in a dissolved form in the water column. And we’ve seen no appreciable improvement in many area lakes, despite millions of dollars spent in required stormwater management facilities.

As mentioned previously, sewage treatment systems have had a major positive impact on water quality. In our area, the Mississippi River is much cleaner than it was in the 1960s. However, nonpoint source regulations have yet to show similar positive results.

What can be done?

So, lots of questions have been raised and criticisms leveled. But what can and should be done? I don’t pretend to have all the answers; however, here are a few common-sense ideas:

  • Standardize regulations: Create uniform regulations that apply across the area. This will save time and effort learning new regulations for each location. That allows for standard approaches to meeting these regulations. There may be some site-specific regulations to address unique conditions of a site, but these should be the exception.
  • Streamline the process: In particular, reduce the number of agencies requiring permits and approvals. Multiple submittals for the same project are costly and inefficient. Ideally, one agency should have regulatory approval, probably with agreements from the other agencies.
  • Perform more rigorous research on urban stormwater: There is not enough solid research on urban stormwater management. We need rigorous monitoring of the treatment effectiveness of best management practices (BMPs) to remove pollutants. This can help identify which BMPs work best and in what circumstances. It also helps develop solid design criteria for the BMPs, which are lacking. Cost data could be included in this evaluation, to better understand the cost-effectiveness of various practices. We should research impacts of infiltration features on groundwater quality. Then, decisions on appropriate stormwater regulations are based on solid data and research.

The bigger questions here concern the place of water quality within the many values of our society. How much water quality is enough? How much do we want to spend on stormwater management?

No one questions the value of good water quality. It’s essential for our health and quality of life. But what about the sometimes-competing values of public safety, social equity, education, and economic growth? We have many elements that contribute to the success and quality of life of our society but finite resources with which to accomplish them. Dollars spent toward accomplishing any one of these comes at the expense of others. We need a solid discussion of how much of our public resources should be spent on any of them, including stormwater management.

In a follow-up blog, I will discuss the impact of stormwater regulations on housing affordability and social equity.

  • Dan Edgerton

    Dan is a senior associate passionate about green stormwater infrastructure planning and design, and the role of surface water in creating engaging and vibrant community spaces.

    Contact Dan
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