Reduced river phosphorus following implementation of a lawn fertilizer ordinance

Figures & data

Table 1 Locations and approximate catchment areas of 4 Huron River stations that are attributable to Ann Arbor. Coordinates are specified as eastings and northings for UTM Zone 17.

Station	E	N	Catchment area attributable to Ann Arbor (km^2)
CTL	262796	4691655	0
A	275285	4685262	29
B	279744	4683268	94
F	284834	4679126	94 + AAWWTP outfall

Figure 1 - Study site, with sampling stations identified.

Figure 2 Fluvial discharge of the Huron River at Ann Arbor (USGS 04174500) from May to September for 3 reference years (2003–2005) and the post-ordinance test year 2008.

Figure 3 Concentration anomalies of SRP, DP and TP at control and experimental sites in 2008 expressed as percent of reference values. Error bars represent upper 90% confidence intervals of the means.

Figure 4 Monthly discharge of TP from the Ann Arbor wastewater treatment facility from 2003 to 2008.