Watershed characteristics and water-quality trends and loads in 12 watersheds in Gwinnett County, Georgia

Lake eutrophication has increased in pace in recent decades and has caused serious environmental problems However, the development trends have not been fully determined as it is difficult to recognize complex effects emanating from both climate and human mechanisms. China has many lakes in different trophic stages, which represent three developing stages from forest- to agriculture-, and then to urban-lake, typically in Lakes Lugu, Taibai, and Taihu. To determine long-term water quality trends, the three lakes were chosen for statistic analysis on dominant effects on the diatom-inferred nutrient changes, and to undertake dynamic modelling regarding climate-controlled nutrient changes. The results indicate the significant turning points of water quality in Lakes Lugu, Taibai and Taihu occurring in the 1990s, 1950s and 1940s respectively, which were effected from human activities by increases in tourism, farming and urbanization respectively. Water quality changes in Lakes Lugu, Taibai and Taihu captured 68.4%, 54.9%, and 86.0% of the temperature variations before the turning points. The anthropogenic impacts explained 84.0%, 96.4% and 96.0% of the water quality variations after the turning points, where the sharp change of water quality by human activity has played an accelerated effect on the gentle change of temperature. Compared with the 4 phases of water quality development in Pyhäjärvi Lake (SW Finland), Lakes Lugu and Taibai have experienced the 1st and 2nd phases, and Taihu has experienced from the 2nd to 3rd phases during the last 150 years. Phase 4 has not occurred in the three lakes, but it is a key period during the eutropication we need to pay attentions.

Download Full-text

Long-term Water Quality Trends after Implementing Best Management Practices in South Florida

Journal of Environmental Quality ◽

10.2134/jeq2008.0462 ◽

2009 ◽

Vol 38 (4) ◽

pp. 1683-1693 ◽

Cited By ~ 26

Author(s):

Samira H. Daroub ◽

Timothy A. Lang ◽

Orlando A. Diaz ◽

Sabine Grunwald

Keyword(s):

Water Quality ◽

Best Management Practices ◽

Management Practices ◽

South Florida ◽

Best Management ◽

Water Quality Trends

Download Full-text

Introduction to the U.S. Geological Survey National Water-Quality Assessment (NAWQA) of Ground-Water Quality Trends and Comparison to Other National Programs

Journal of Environmental Quality ◽

10.2134/jeq2008.0049 ◽

2008 ◽

Vol 37 (S5) ◽

pp. S-190-S-198 ◽

Cited By ~ 27

Author(s):

Michael R. Rosen ◽

Wayne W. Lapham

Keyword(s):

Water Quality ◽

Quality Assessment ◽

Ground Water ◽

Water Quality Assessment ◽

Geological Survey ◽

Ground Water Quality ◽

National Programs ◽

Water Quality Trends ◽

The U.S ◽

National Water

Download Full-text