Monitoring Results – Annual Flow, Precipitation, TSS and Phosphorus: WY 2004
Study Overview and Background
Five USGS continuous monitoring stations within the 1,580 km2 Lower Fox Basin have been installed directly through the project. The following stations will provide 3 years of data beginning in October 2003 and ending September 30, 2006:
Stream flow and water-quality gaging stations were installed on three streams (Apple Creek, Ashwaubenon Creek and Baird Creek). A water-quality sampler was installed at Duck Creek. An acoustic velocity meter (AVM) and water-quality sampler were installed at East River. Stream flow measurements were made at all sites to determine stage–discharge relations. Over 480 water-quality samples were collected during events and low flow conditions and analyzed for suspended solids and total phosphorus. Over 210 samples were analyzed for dissolved phosphorus. The USGS computed daily total phosphorus (TP) and total suspended solids (TSS) loads for each stream, and will estimate dissolved phosphorus (DP) loads. TSS concentrations have also been correlated with turbidity data from sondes operated by UW-Milwaukee. Four rain gauge-logger units were installed at the USGS stations by the USGS, and 11 tipping bucket rain gauges and loggers have been installed throughout the basin by UWGB.
1) Better understand cause/effect through event and continuous monitoring.
According to the Green Bay National Weather Service Station, the second wettest May on historical record was recorded in 2004 (211 mm). With 3-times the normal precipitation, this rainfall was responsible for excessive runoff and loads in May and early June. However, total annual precipitation in WY2004 (813 mm) was only 10% above normal (741 mm). Annual stream flow ranged from 33 to 43% of total precipitation.
Apple, Ashwaubenon and Baird Creeks had similar median TSS concentrations of approximately 127 mg/L, which is 2.5 times greater than the median value from previous studies. Much lower TSS concentrations of about 67 mg/L were determined for Duck Creek and East River; however, it should be noted that East River samples were typically composites of four samples per day. Maximum TSS concentrations ranged from 960 mg/L at Duck to 2,700 mg/L at Baird.
High TP concentrations were found in all streams. TP median concentrations ranged from 0.28 in Duck Creek to 0.70 mg/L in Ashwaubenon Creek. About 25% of Ashwaubenon Creek samples were greater than 0.93 mg/L. Samples in excess of 2 mg/L TP were collected from all sites.
Annual median DP to TP fractions ranged from 49-57%. Median DP was 40-54% of TP during events and greater than 70% DP during low flow.
Annual loads were highly event driven: 13 days accounted for 80% of the TSS load and 67% of the TP load from Apple Creek. Baird Creek was less influenced by events: 13 days accounted for 67% of TSS and 52% of TP loads. Excluding Apple Creek, March, May and June accounted for 87-96% of the TSS load and 81-88% of the phosphorus load in the 2004 USGS water year.
Annual TSS yields from Apple, Ashwaubenon and Baird were similar: 0.93, 0.70, 0.72 t/ha, respectively. TSS yields were 0.33 t/ha from Duck and 0.55 t/ha (partial year) from the East River. Annual TP yields from Apple, Ashwaubenon and Baird were similar: 1.9, 2.0 and 2.3 kg/ha, respectively. TP yields were 1.1 kg/ha from Duck and 1.7 kg/ha from the East River (partial year).
See poster for more details regarding flow and water quality monitoring results in 2004.
WY 2004 monitoring data from this project were published in the following USGS publication: