The SR 431 monitoring site is located on State Route 431 (SR 431) in Washoe County above Incline Village, Nevada. The catchment outfall discharges directly into a perennial stream called Deer Creek which connects with Third Creek and discharges into Lake Tahoe, giving this site the distinction of being directly connected to the lake despite being 2.5 miles from it. Lake Tahoe is an impaired water with TMDLs for: clarity, dissolved oxygen, plankton count, soluble phosphorus, and total soluble inorganic nitrogen.
Monitoring performed at the SR 431 site can be used for evaluating and comparing the effectiveness of two adjacent stormwater treatment vaults containing different cartridge filters, an Imbrium MFS vault and an Imbrium Jellyfish vault. There are four monitoring stations at SR 431; the inflow and outflow to the Contech MFS vault, and the inflow and outflow to the Imbrium Jellyfish vault. Though located in a rural area with moderate highway traffic density, the SR 431 site isolates runoff from the highway and will also provide characterization of pollutants that specifically can be found in highway runoff for the area.
Meteorological data is collected at the SR 431 monitoring station.