Thread by @bethanykraft

#DWHStories How does one actually go about determine the environmental impacts of the #DWHOilSpill? The blowout happened a mile beneath the surface of the ocean, affecting the habitats and wildlife in the sea, but also impacted our coastal resources as well.

This week we will peak under the hood of how the impacts were quantified. The Natural Resource Damage Assessment (NRDA, pronounced NERD-A) is a legal process used by the federal government, states and Tribes to evaluate the impacts of oil spills.

In the NRDA process, these entities, known as Trustees, evaluate the extent of damage to natural resources as well as the impact the oil spill had on humans’ use and enjoyment of those resources.

In addition to determining what the impacts are, and how severe they are, the Trustees are also responsible with coming up with the best ways to address the damage, and bring the environment back to where it would have been had the spill not occurred.

I think of the NRDA process as “Old Testament Restoration”. The process allows for trustees to quantify the extent of the loss, and then the responsible parties pay claims necessary to replace the equivalent of the lost resources. A pelican for a pelican, if you will.

As you can imagine, assessing the extent of the impacts of a spill as extensive as the #DWH was quite a complicated endeavor. So, how does it actually happen? As I noted above, the Trustees are responsible for assessing impacts and coming up with a plan to address them.

In the case of the #DWH, two primary documents drive this process. The first was developed in 2011 and is known as the Early Restoration Framework. This came about as an effort to start addressing known impacts even before the assessment was complete. tinyurl.com/vtgvydl

For early restoration, BP put $1 billion down for restoration efforts to begin, which would be counted toward the dollar amount for the final claim--everyone knew it would be substantial, and the longer it takes to get restoration underway, the more expensive it gets.

As early restoration began, the Trustees continued the damage assessment, and in 2016, after a settlement was reached with BP, they released a huge document known as the Programmatic Damage Assessment & Restoration Plan & Programmatic Environmental Impact Statement (PDARP/PEIS)

This beast of a document quantifies the extent of the impacts for all injured resources and identifies a set of choices, or alternatives that the Trustees could use to address them.

The Trustees characterized the injury thusly, “Overall, the ecological scope of impacts from the Deepwater Horizon incident was unprecedented, with injuries affecting a wide array of linked resources across the northern Gulf ecosystem. “

Given the extent of the impacts, the Trustees decided to take a comprehensive, integrated approach to restoration, treating the ecosystem like, well, like one connected system. The executive summary lays out the process and approach nicely, though it is 70 pages on its own.

Note: I had nothing to do with drafting the PDARP/PEIS or the assessment, but I have read the entire thing, plus appendices, and I find it to be really impressive. tinyurl.com/yx5n32gs.

The trustees weren’t the only ones studying the impacts of the spill. Here are a few papers that examine various impacts in the coastal area.

Coastal and continental shelf impacts tos.org/oceanography/a…

Impacts on salt marsh vegetation in Louisiana
sciencedirect.com/science/articl…

Shoreline oiling
sciencedirect.com/science/articl…

Oil Spill Impacts on Alabama Beaches
researchgate.net/publication/30…

Impacts to terrestrial arthropods
digitalcommons.lsu.edu/cgi/viewconten…

One more interesting paper, on the impacts of the oil spill response effort:
int-res.com/articles/theme…