The Illinois River Watershed
The Arkansas-Oklahoma Arkansas River Basin Compact Commission met in September 2018 and received reports on water quality and water quantity in Arkansas and Oklahoma portions of the Illinois River watershed.
The trend shows a continued decline in phosphorus in the watershed. However, phosphorus is still higher than the limit set for Oklahoma Scenic Rivers. That limit is 0.037mg/L. That limit is exceeded by 88-percent at the Arkansas-Oklahoma border near Watts, Oklahoma. It is exceeded by 75-percent downstream at Tahlequah.