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Stormwater rules creating rough seas for airport plan
With 4.7 acres of concrete, pavement and other impervious surfaces, Bremer-ton National Airport needs a king-sized system for handling runoff, particularly during heavy rainfall.
The question now is whether the airports mega-system is enough to handle the proposed runway shift, and the stricter stormwater management requirements which come with it.
The Port of Bremerton, which oversees the airport, has known for some time the mile-plus-long runway would have to be moved. At its north end, the runway comes within a few hundred feet of State Route 3. The FAA requires, at a minimum, a 500-foot by 1,000-foot area of clearance at both ends of the runway.
To comply with the requirements, the port plans to dig up approximately 147,000 square feet of the runway and 49,000 square feet of the adjacent taxiway. A similar area south of the runway will then be paved, effectively moving the runway several hundred feet to the south and leaving the north end clear of the highway encroachment.
Its a very high priority for us to get safety areas at all of our airports, said FAA Environmental Specialist Cayla Morgan. They dont have that right now.
However, when the port proposed the shift, it got the attention of the Department of Ecology and National Marine Fisheries (NMFS). Even though the net impervious surface at the airport will remain the same, moving more than 5,000 square feet of soil nearly one-fortieth of the amount proposed requires an environmental assessment. It also means the port, whose stormwater system was built under NMFS 1992 rules, could have to be upgraded to comply with its more-stringent 2001 rules.
They just want to make sure we dont impact things down-range, said Airport Manager Fred Salisbury.
Because the airport sits at the headwaters of several major waterways, including the Union River, there is quite a bit down-range for NMFS to be worried about. The port, however, feels its stormwater system is up to specifications, even under the new, tighter rules.
If it isnt, the port could be forced to upgrade, at an estimated cost of $250,000 to $600,000 or more. In addition, any upgrade would probably require the retention pond, which now holds more than 1 million cubic feet at maximum capacity, to be significantly enlarged.
That, Salisbury said, could spawn a new set of difficulties. The pond sits at the south end of the runway, the end slated to be enlarged.
Youd have a water hazard three times the size of the old one sitting right next to the runway, Salisbury said.
Salisbury, Morgan and a NMFS representative toured the airports stormwater system last Wednesday to assess the possible need for improvement. Salisbury said the NMFS official seemed pleased with the current system and said there was a strong possibility no changes would be needed.
Morgan also expressed optimism the project would be allowed to move forward as planned.
It looks like it can be handled, she said. Theres things we have encountered, but theyre all manageable.
However, Morgan added: It is not a this-summer project, I can tell you for sure.
Even if the port manages to avoid costly upgrades with this project, every future project will be held up to the same or stricter standards. For that reason, Morgan said its probably only a matter of time before the port needs to make changes to its stormwater system. In fact, she said, they may need to upgrade as soon as their next project, whenever that is.
The port, however, is not looking forward to that possibility.
You build on the assumption your project is going to be grandfathered in, Salisbury said.