At the Straitgate Inquiry, much of the hydrogeology discussion centred around the speed at which groundwater travels through the unsaturated zone.
The barrister for Devon County Council said in his closing submission:
52. In the face of the literature that has measured speed down through the Sherwood Sandstone (of which the BSPB is part) of 1.06m/year, the Appellant advances a remarkable claim: that speed is in fact in a range up to 16.9m/day, by reference to some open borehole and trial pit testing and relying on relatively rapid responses to rainfall shown by borehole loggers measuring (through pressure) the level of the water table.
What a coincidence then that during the Inquiry this paper should be published:
A global scale dataset of #nitrate migration speed through unsaturated zones that can support understanding the nitrate legacy in #groundwater & management solutions https://t.co/mVKiCCPcRD
— Mike Jones (@GroundwaterMike) October 12, 2022
It concerns the international problem of nitrate pollution in groundwater:
When understanding the impacts of this nitrate legacy on water quality, the nitrate transport velocity (vN) in the unsaturated zone (USZ) is of great significance. Although some local USZ vN data measured or simulated are available, there has been no such a dataset at the global scale. Here, we present a Global-scale unsaturated zone Nitrate transport Velocity dataset (GNV) generated from a Nitrate Time Bomb (NTB) model using global permeability and porosity and global average annual groundwater recharge data.
As anyone casting their eye over the paper will see – velocity in the unsaturated zone is measured in metres per year NOT metres per day.
