Costs
The per linear foot cost of the permeable reactive barrier is based on a barrier height of 35 feet. Look under the Resources tab to get a sense of the depth to bedrock (shale) and the depth to the water table from the Drillers' Logs of Site Test Holes and the water-level fluctuations in the Well Hydrograph, also under the Resources tab.
Question:
What factors determined that the barrier height should be 35 feet?