A Survey of Halfway Creek, La Crosse County, Wisconsin to Determine Temperatures, Nitrate-Nitrogen, Nitrite-Nitrogen, Ortho-Phosphate, and Sediment Present in the Creek

Abstract

The concentration of nitrate-nitrogen, nitrite-nitrogen, and ortho phosphate were determined from samples taken at six different locations, every two weeks for a year, on Halfway Creek in La Crosse County, Wisconsin. The temperature and the amount of sedimentation were also recorded for each station. The sampling and analysis began July 22, 1971 and ended June 28, 1972. The six stations were located between the mouth of Halfway Creek on Lake Onalaska and a point about two miles downstream from its source in the coulee. The results show a considerable variation in the amounts of nitrate, nitrite, and phosphate present at different times of the year and at the different locations on the stream. The average ortho phosphate level of the stream was 1.82 ppm, with very high levels recorded in the spring. The nitrate level of Halfway Creek was highest in the farmland near its source, decreasing as it moved toward its mouth. The average amount of nitrate present in the entire stream for the year was about 34 ppm. The nitrite level averaged 0.112 ppm over the entire stream for the measuring per oid. Sedimentation was very low with very little suspended material leaving the stream at its mouth in Lake Onalaska. While most of the temperatures recorded produced characteristic results, those recorded at the mouth of the stream were exceptions. They were generally lower than the next two stations upstream because of large amounts of water entering the stream just before it empties into the lake.