Managing Stormwater Under Increasing RegulationsPublished on April 5, 2018
The handling of stormwater runoff is becoming an increasingly significant management issue in terms of the regulatory world – and consequently for individual sites.
There are reams of literature that freely flow through the internet, and various agencies throughout the world are cutting down more and more trees to prepare manuals, regulations and case studies.
While few will argue with the concept of clean water, implementing its ever-increasing rules, depending upon the location, can be worse than having teeth pulled without Novocain. There are often different written requirements, interpretations and “causes du jour,” which can differ across the country, within a state, or within a locality. At times, they can even differ within a given set of agency rules.
Here in New York, for example, the state’s stormwater guidance manual has numerous conflicting requirements from section to section and sometimes even within a given chapter. And that manual can often be in conflict with what a facility might need to do under its industrial facilities stormwater permit.
Ultimately, the regulations want to prevent stormwater from entering into and contaminating the receiving waters. Filtering and even treating the water becomes the challenge.
For the marina industry, it can be even more challenging to find solutions. In most cases, marinas are at the lowest topography along the water’s edge. As a result, they are typically faced with high ground water and are often receive stormwater runoff from the surrounding uphill areas.
High groundwater creates problems for achieving the separation that most regulatory guidelines seek between the bottom of stormwater management measures, particularly infiltration practices, and the groundwater level. While the goal of the regulations is clean water, the realities of the waterfront are typically absent from the rules, and too often bureaucrats only see the world in black and white: you comply 100 percent or you don’t.
Being the recipient of runoff from areas uphill of your marina can add volume, and complicate your efforts to achieve regulatory benchmarks since the areas upstream are beyond your control. It is also not uncommon for municipal stormwater outfalls to pass through marina uplands and discharge into the marina waters. This can be both frustrating, as you see what is coming out of the municipal line, and problematic, as often the municipal stormwaters are as great or a greater source of water quality issues in the marina’s waters as the runoff from the marina itself.
There are four basic areas to deal with regarding stormwater at marinas: a.) from roofs, b.) from outdoor work and boat storage areas c.) from parking and road areas, and d.) from all other areas.
We tend to think of roof stormwater as relatively clean, but depending on the roof different contaminants may be getting deposited there, from indoor ventilation systems, atmospheric or avian deposition (those darn seagulls!), or roof material that comes off. In fact, for marinas with large work sheds or rack storage buildings, it is more often the latter that may be contributing to your stormwater problems –specifically your zinc levels, and the potential source being the galvanized steel used for the roof. That’s not to say that all galvanized roofs will be a problem, but it is something to consider. And if your roof is shedding zinc or other contaminants, you might want to consider something like a downspout filter unit with metal absorbing insert. Alternately, stormwater from roof areas could be directed to some type of catchment area and filtered, and then allowed to either seep into the ground or discharge through pipes to the receiving waters after having been filtered.
Further complicating matters in the U.S. is that marinas and most similar entities have been declared stormwater “hotspots.” The implications of this designation can vary, including whether the hotspot applies to the entire facility or only those areas where outdoor boat maintenance activities (such as power washing, hull maintenance, sanding, blasting, welding, painting, fiberglassing, caulking, etc.) or, in most cases, even outdoor boat or materials handling and storage occur. Dealing with stormwater from ‘hotspots’ can be more challenging as there are additional potential contaminants that one needs to handle and increasingly more restrictions as to how that can be accomplished – oftentimes this can mean limitations on many of the more traditional in-ground filtering techniques.
For roads and parking lots that are not used for boat storage or maintenance activities, some of those more traditional filtering practices, such as the use of infiltrators, may still be available – and these methods and a variety of others normally can be used to handle most “other” areas, such as pool decks, terraces, tennis courts, etc.
But for those so-called hotspots, in addition to water treatment, one is also typically looking to achieve pollution prevention. In a perfect world, the simplest approach is to thoroughly clean up the area after these activities take place. With this approach the ground – whether pervious or impervious – is clean, and, therefore, stormwater traveling over it would not pick up potential contaminants.
To keep the ground clean, there are numerous options. For sanding – using dustless sanders can contain most of the materials being removed from the hulls. Where work is being undertaken over pervious surfaces, such as crushed stone, grass, etc., a geotechnical/filter or other fabrics/tarps can prevent the debris from landing on the ground. They can also be cleaned or rolled up and thrown away, leaving the ground clean for stormwater to flow over it without picking up potential contaminants. A useful addition to the tarps is planks of wood or hay bales along the edges to help both keep the fabric in place and to help contain the material that has fallen onto it.
Screens are also very helpful, as is trying to curtain off various activities. An inventive approach we have witnessed is the use of tall mobile screens weighted at the bottom to prevent them from being blown over in the wind. Together with the use of ground covers, they have helped the facility keep itself shipshape. It is suggested that particularly slick plastics and similar materials not be used as ground covers as the wind can easily blow materials off them before one has had a chance to clean up the materials.
Regardless of what material is used, remember that it doesn’t do much good if the tarps are not carefully collected or if they are left out in the rain. I can’t tell you how many times I’ve seen a tarp that had been carefully laid out ahead of and throughout the work, then carelessly picked up at the end with all the collected sandings and paint chips simply falling to the ground.
For your facility’s impervious work areas, one can do the same or sweep and/or vacuum up the materials.
For power washing or wet blasting work, facilities must deal with the water from the operations, as well as rainwater. It is recommended to be over hard surface areas, as conceptually it is usually easier to handle both waters and the debris from the hulls together. Generally, the waters can be channeled to a sump, directed through filters and discharged to a sanitary system, a recycle system, a holding tank or containment area, again often depending on local rules. The power wash and blast water is not allowed to be discharged into receiving waters – streams, rivers, ponds, lakes or coastal waters. The surfaces then need to be swept, vacuumed or otherwise cleaned.
The stormwater cannot go into a sanitary system, so if a sump is used, stormwater typically has to be directed to its own filters and then can be discharged onto or into land areas or receiving waters.
There are numerous approaches to both filtering and treating the “industrial waters.” There are numerous filtrations systems. There are also recycle systems that use a variety of techniques. Some use what is called a flocculation and coagulation approach, where a chemical is added to the water, essentially encapsulating the contaminants and pulling them out of the water. The water then goes into a holding tank and is able to be reused.
Using common sense and best management practices is the key to having clean stormwater and a clean site.
Keep in mind that what may be required during construction or upon completion of new development may be different from what you may need to do as an existing facility. In both cases, solutions can be simplistic to highly engineered. By understanding the objectives of the programs, you can tailor the controls to be effective for each portion of your site.
And at the end of the day we all want a clean site and clean water!
Dan Natchez is president of DANIEL S. NATCHEZ and ASSOCIATES Inc., a leading international environmental waterfront design consulting company specializing in the design of marinas and marina resorts throughout the world. He invites your comments and inquiries by phone at 914/698-5678, by fax at 914/698-7321, by e-mail at firstname.lastname@example.org or on the Web at www.dsnainc.com.