There’s a 20-foot gap between the current breakwater and the proposed wave barrier in the Portage Cove Small Boat Harbor. And that relatively small, planned space is now turning into a big problem. The Army Corps of Engineers says the gap won’t fly, but the solution could be very costly.
The Army Corps wants that gap between the wave-barriers closed before they’ll issue the required 408 permit. The Corps says that 20-foot space has the potential to funnel waves in, which could potentially disrupt the rubble mound.
Harbormaster Shawn Bell said last week that PND Engineers did a study on the potential for waves blasting through the gap. Engineers predicted that in a scenario with an extreme high tide, and an above-average storm, a one-foot wave would wash inside the harbor. In the case of an extreme high tide and a 50-year storm, PND expected a two-foot wave inside the harbor. Bell says both of those scenarios meet design criteria. But the Corps has other ideas.
“The Army Corps is wanting to have that gap closed. They’re worried about the waves funneling in there at an increased velocity and dislodging some of the rocks.”
Bell says there are two potential fixes: close the gap with the sheet barrier, or extend the rubble mound. But both would require extensive, and expensive, excavation and more.
“PND is looking at a couple different options for how they can economically close the gap.”
Interim borough manager Brad Ryan says the space is necessary because of the slope of the existing rubble mound. This gap conundrum is holding up the progress of the Corps-required 408 permit. The 408 permit is needed when a planned project ties into an existing Corps project. In this case, the rubble mound. He says the borough knew about the gap and were informed by the engineers that only on rare storm occasions would the waves inside the harbor reach up to two-feet.
“So you have this gap that’s not closed off because you start thinking about cantilevering metal sheets, or you shove more piling in there, or you start stacking larger rubble. One of the problems with the rubble has been the question of the stability of the bottom clay layer. No one wanted to do that without (putting in) a bunch of wick drains, which increases the cost. It’s not a problem as much with the engineering as it is the cost increase.”
Wick drains, or prefabricated vertical drains, are used to create more stability in soft soils, like the clay at the bottom of the harbor.
For now, the borough is waiting on the Army Corps recommendations. Ryan says there’s not much they can do until then
“The issue is the recommendations that the Corps comes back with, if PND agrees, and then what is the additional cost. That’s the real questions that we’re waiting on. We actually talked to the Corps this morning and they’re still waiting on their engineer to review it and make recommendations. So, we don’t know if it’s a big deal yet. We hope not. But that’s the million-and-a-half-dollar question.”
The fix could cost a million dollars, or it could cost $5 million, or it could cost more. He says the cost of the fix will have to come out of the money already allotted for the project, that’s about $20 million. So something else in the plan will have to give. Ryans says some of the early numbers offered may hurt the project a little, but they’re not a “sinker.”
“I suppose at some price point it’s a dealbreaker and that’ll have to come back to the Ports and Harbor Commission, and us, and we’ll have to decide if it’s worth pursuing. If it came back and it was $10 million more, it would be the same price as a rubble mound and maybe we do that instead. But, we don’t have that kind of money in our coffers, regardless.”
Ryan says the new development is concerning. It comes after the proclamation of good news earlier this month that the project was moving forward through the permitting process.
“In a lot of ways, it’s moving forward fast; much faster than I had anticipated. It does come on the heels of some good news, but there’s always a catch here and there.”
Port and Harbor Advisory Committee member Terry Pardee shared his frustration at a meeting last week about the new glitch. He says with commercial fishing vessels getting bigger, and the plans for the harbor getting smaller, the facility won’t be very useful for future generations.
“It almost seems like somebody doesn’t want to see this thing happen at all. And I’d dearly like to find out who it is.”
Ryan says the borough hopes to hear more details from the Corps and PND this week, and come up with a viable solution to the gap.