Thursday, March 24, 2016

Grading on a Curve: Preparing for Sod

This week, everyone in the Bryant Park offices has been talking about grading, and we don't mean pass or fail! This type of grading concerns the precise leveling of an area of soil. It's an essential part of re-creating the lawn each spring.

Grading enables drainage, and drainage is essential. First, the lawn needs to be able to drain quickly after rainstorms so it can continue to host our packed schedule of free events this spring, summer and fall. Second, the lawn sits on top of the New York Public Library's underground storage, which contains millions of volumes of books. If you've ever spilled water on paper, you know that a poorly-draining lawn would spell danger for the literature.

It may look quiet in the park, but the careful process of grading is underway.

Grading occurs after the ice rink has completely left the park, and the dirt underneath is exposed. Additional truckloads of dirt are brought in, and the landscaping crew gets to work flattening and raising the lawn to match the specific contours needed for optimal drainage. They employ several different methods to do this, including what looks to the untrained eye like water-skiing without the water. 

The park sits around 67 feet above sea level, believe it or not, and measurements for drainage are based upon that elevation. After the dirt is in place, staff check its relationship to the height of the curb that surrounds the lawn. They use a surveying tool called a "transit level" to make sure that everything lines up.  Then the lawn's sprinkler system, which is removed each fall for the rink's construction, needs to be reinstalled and calibrated. With all that taken care of, it's time to lay the sod! 

We'll update you on the lawn's installation, progress, and anticipated opening day throughout the next several weeks so stay tuned!  

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