The Linnean Daylighting Project And Those Boulders

Thanks to all who came out to the Broad Branch stream daylighting tour yesterday! What an impressive turnout. If you were on the tour, you couldn’t miss the rust-colored boulders being used in in the project. One neighbor has been curious about them, and about when work will begin on the nearby Linnean Playground project. Here’s what he learned.

by Paul Walters

Like many in the neighborhood, I have had my eye on developments at three major projects in Forest Hills: The Broad Branch daylighting at two sites east and west of Linnean Avenue near Broad Branch Road, and the Linnean Playground project area that runs between Broad Branch Terrace and Linnean Avenue north of Fessenden.

In some respects, the projects are large-scale public “landscaping” works. One aspect that is very striking are the massive reddish-brown boulders that began arriving in the area several weeks ago.

‘Bog iron’ stored along Linnean Avenue for the Linnean Playground project (photo by Paul Walters)

I asked Steve Saari, District Department of the Environment program manager for the Broad Branch daylighting project and for the Linnean Playground project, what these boulders are and where they came from.

Steve writes: “I don’t know the exact location of where the boulders came from, but they are from Anne Arundel county. Our contractor loves to utilize this type of stone because it is strong and it is porous which allows plant life to readily establish on them. They also have a higher iron content so they are a bit acidic which helps keeps invasive plants out and encourage the plants that are what we’d like in these systems.

“The type of stone is called ‘bog iron’ and is generally found in coastal plain areas and headwater streams where bogs form behind beaver dams. It is not a typical quarry stone so it is a bit rare (and unfortunately can sometimes drive up the cost of a stream project). We were fortunate in that our contractor got the stone at a site where a sub-development was going in and the developer wanted to remove the stone. Our contractor leapt at the chance to get the stone but it meant we needed to stockpile it at the site while we waited to have all our permits for construction.”

A small mountain of bog iron is waiting at the Linnean Playground site for that project to begin. Steve told me that as soon as some internal agency paperwork is finished, the Linnean Playground project will get underway “in about a week or two.” Meanwhile, contractors have deposited materiel near the project site in preparation for the work to begin.

The Linnean Avenue end of the Linnean Playground stream has frequently looked rankly overgrown and uninviting – especially later in the summer after a season of growth. Steve Saari says, “We will be removing and controlling a lot of the invasive plants that are in that area and then planting it with more native species. Our hope is that it will look like an inviting entrance to a stream valley.”

The bog iron and other hardscape, and the new planting and changes to the aquatic environment, promise to bring many welcome changes to that region of Forest Hills.