Aluminum application to restore water quality in eutrophic lakes: maximizing binding efficiency between aluminum and phosphorus

Figures & data

Table 1. Background information for Lake Harriet.

	Units
Surface area	ha	139
Mean depth	m	8.7
Maximum depth	m	25.0
Watershed area	ha	461
Residence time	y	4.3
Al dose	g/m^2	32
Treatment date		May 2001

Figure 1. Depth contours, coring location, depths, and approximate Al treatment zone for Lake Harriet. All depths are in meters.

Figure 2. Aluminum (Al) added, Al-bound P (P_Al) formed, and the ratio between added Al and P_Al formed from cores collected at 4 (a), 11 (b) and 24 (c) m water column depth between April 2001 (pre-treatment) and October 2011. Dashed line represents the date of Al treatment.

Figure 3. Internal P release rate (Li) before and after Al treatment, indicated by the dashed line.

Figure 4. Mobile and Al-bound P (P_Al) concentrations (dry weight) at the deep coring location (24 m) from April 2001 to October 2011. Dashed line indicates date of Al treatment.

Figure 5. Concentrations (dry weight) of aluminum (Al) and Al-bound P (P_Al) by depth at 24 m water column depth in October 2011. Vertical dashed and solid lines denote background concentrations for Al and P_Al, respectively.