A water-quality assessment of the Jordan Creek watershed was made September 24 and 25, 1974. Surface waters within the watershed were calcium bicarbonate types with very similar concentrations of major dissolved constituents and specific conductance values. Streamwaters contained less than 0.26 milligram per litre dissolved nitrate (as N), 0.03 milligram per litre or less dissolved phosphate (as P), and from 4.8 to 5.9 milligrams per litre dissolved organic carbon. Fecal coliform bacteria concentrations were between 220 and 1,400 colonies per 100 millilitres and fecal streptococci concentrations ranged between 85 and 330 colonies per 100 millilitres. Bed material in lower Jordan Creek contained dieldrin, DDD, and DDE in concentrations less than 0.6 microgram per kilogram. A reasonably good biologic diversity index of 2.9 was found in a lower Jordan Creek sampling site. The benthic community was dominated by midge larvae. Phacus sp (flagellate) and Navicula sp (diatom) dominated the lower Jordan Creek phytoplankton community and Cladophora sp (green algae) was the dominant periphyton.
