||Alum Control of Internal Phosphorus Loading in a Shallow Lake.
Welch, E. B. ;
Michaud, J. P. ;
Perkins, M. A. ;
||Washington Univ., Seattle. Dept. of Civil Engineering.;Corvallis Environmental Research Lab., OR.
Water pollution control ;
Aluminum sulfate ;
Water quality ;
Organic loading ;
||Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy.
||Alum treatment of a shallow lake, with mean depth 2 m and area 137 ha, curtailed internal loading of P for at least one year. Mean summer total P and chl a decreased from 76 and 27 micrograms/l, respectively, in 1978 before treatment, to 29 and 14 micrograms/l, while mean summer Secchi transparency increased from 1.6 to 2.2 m and blue green algae were no longer dominant. Macrophyte biomass and distribution returned during the post-alum year, 1980-1981, to previous levels after a 1979 four-month lake level drawdown had reduced biomass by 84 percent. The improved transparency, resulting from the decrease in chl a following treatment, could encourage greater biomass of macrophytes in the deeper area of the lake. Recovery of macrophyte biomass to predrawdown levels may restore internal loading of P through enrichment of deep water sediments during winter dieback and decomposition.
||Pub. in Water Resources Bulletin, v18 n6 p929-936 1982.
|NTIS Title Notes
||Reprint: Alum Control of Internal Phosphorus Loading in a Shallow Lake.
|PUB Date Free Form
||8H; 68D; 48G
||Not available NTIS