SUSMP Gone Wild

By Timothy Allinson, P.E.

Murray Company, Long Beach, Calif.

Remember when "green" referred to money? Perhaps it still does today, but indirectly so. It now refers to the industry dedicated to making money while saving the environment - a noble, profitable and political cause.

Don't get me wrong - I am not an advocate of environmental irresponsibility. In fact, I was thrilled the other day when I read that the bald eagle had been taken off the endangered species list. Over the last 40 years it has increased its numbers from 400 mating pairs in 1967 (nearly extinct), to more than 10,000 this year. You may recall that the use of DDT as a pesticide infected the fish that the eagles ate, which in turn caused their eggshells to be paper-thin and incapable of bearing chicks. That would have been a disaster, had that beautiful, majestic bird - the symbol of our great country - become extinct. The environmentalists performed a miracle in saving that species.

The environmentalists of Los Angeles County are trying to perform miracles as well, except the basis of their science is less sound than the research done on the bald eagle. And I'm sure that Los Angeles is not alone in this respect. If your town USA has not jumped on the bandwagon yet, it's likely only a matter of time.

Being a coastal county, Los Angeles desperately wants to clean up its waterways. The whole country wants to clean up its waterways and ground water. That's why in 1996 the National Pollution Discharge Elimination System (NPDES) was amended to include the Standard Urban Stormwater Mitigation Plan (SUSMP). (Read more on SUSMP in the August 2006 issue of Plumbing Engineer.) The trouble with SUSMP is that there's nothing "standard" about it, making it a frustrating plan for the engineer.

The SUSMP document itself is specific in some ways and vague in others. Once you sift through all the acronyms typical of any government document, it tells you specifically which construction projects must comply with its requirements, but it's pretty vague in the "how" department. It references best management practices, rather than specific technologies, and in its vagueness it leaves a lot of slack for the local authority to gather up.

Until January of this year, SUSMP requirements could be met here in Los Angeles by using a clarifier in the stormwater line just before or after it exits the building, Units manufactured by companies such as Rinker, Contech and Jensen Precast (to name just three) worked well to this end.

Then, the Heal the Bay Foundation successfully sued the state of California over stormwater discharge violations, so the state's Regional Water Boards have in turn come down hard on the various counties and cities regarding SUSMP.

They decided that we in L.A. should be doing what the tree-huggers in Portland are doing (sorry Portland), which is infiltrating the icky first 3/4 in. of rainwater into the ground. That might work well in Portland, where the soil characteristics and landscape are very different than they are in Tinseltown, but it is madness in Los Angeles.

It seems the powers that be in Los Angeles County have forgotten that they live in what used to be a desert, and as is the case in most deserts, the earth is hard clay and sand and not in the least bit receptive to water. They also fail to realize that buildings in Los Angeles are built to the property line, unlike many of the buildings in Portland. Accordingly, stormwater cannot be diverted to landscaped areas for infiltration into the ground.

These fairly obvious facts were pointed out to the city on project after project. So the city then insisted that the first 3/4 in. of stormwater had to be directed into the soil below the building. You can imagine how excited the structural engineers were about that design. Typically we, the plumbing trade, must install a foundation drainage system around any building with one or more basement to protect the foundation from the effects of ground water. Now the city was insisting that instead of removing groundwater, we should introduce more of it. Makes perfect sense, doesn't it?

After more heated meetings with the city, they agreed to approve an alternative design. This is my favorite part. If we could provide a letter from the geotechnical engineer stating that the soils were not receptive to water, and a letter from the structural engineer stating that the introduction of large amounts of water below the foundation would compromise the building's structure, then the city would accept an alternate design that filters the first 3/4 in. of rainwater through planters, provided the stormwater is filtered before and after the planters as well. I can't remember who said it, but it remains true that there is nothing more powerful than the momentum of a bureaucracy put into motion.

The planter filtration scheme is of course riddled with problems. The landscape designers are up in arms that the dirty first-flows of rainwater will poison their plants. Then there's the fact that the flow of water cannot be controlled to the planters (short of a sophisticated cistern pumping scheme), meaning that during heavy rains the plants and soil will likely be washed out of the planter as they would if you were to water your own plants with a fire hose.

I asked the city if we couldn't achieve the same effect or better by using a sand filter. The response was that a sand filter does not provide organic digestion of phosphates. The obvious retort was that the contact time required to achieve organic digestion would not be achieved in the few minutes or seconds that the stormwater would be in the planter's soil, but I bit my tongue rather than beat my head against the desk in argument.

As of this writing, this is the state of affairs of SUSMP madness in Los Angeles County. None of these planter filtration or groundwater infiltration schemes have been installed and put to the test as of yet. I expect that once they are the standards will change. But until the first failures are realized this is what we are stuck with. Of course the failures, when realized, will be the fault of the construction team and not the bureaucrats who forced their execution.

In fairness to the city officials, they were honest in admitting that they were not fond of imposing these absurd designs on the construction team. But, decisions had been made by those who know nothing about construction-just that these things must be done to save the environment. Otherwise both the developer and the city that approved the drawings would be fined $10,000 each per day in violation. Now, that's what I call thinking green.

Timothy Allinson is a Senior Professional Engineer with Murray Company, Mechanical Contractors, in Long Beach, Calif. Prior to entering the design-build industry he worked for Popov Engineers, Inc. in Irvine, Calif, and JB&B in New York City. Tim holds a BSME from Tufts University and an MBA from New York University. He is a professional engineer licensed in both mechanical and fire protection engineering in various states, and is a leed Accredited Professional. Tim is a past-president of ASPE, both the New York and Orange County Chapters, and sits on the board of the Society of American Military Engineers, Orange County Post.