Long-term Trends in Water Quality following Implementation of Controlled Drainage

2016 ◽  
Keyword(s):  
Water Quality ◽  
Controlled Drainage ◽  
Long Term Trends

scholarly journals Determining Long-Term Trends of Four Fast-Eutrophicated Lakes in China and Finland

2015 ◽  
Vol 8 (1) ◽  
pp. 39 ◽  
Author(s):  
Mengna Liao ◽  
Ge Yu ◽  
Anne-Mari Ventelä ◽  
Xuhui Dong
Keyword(s):  
Water Quality ◽  
Anthropogenic Impacts ◽  
Turning Points ◽  
Dynamic Modelling ◽  
Sharp Change ◽  
Temperature Variations ◽  
Long Term Trends ◽  
Nutrient Changes ◽  
Water Quality Trends

<p>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 1<sup>st</sup> and 2<sup>nd</sup> phases, and Taihu has experienced from the 2<sup>nd</sup> to 3<sup>rd</sup> 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.</p>

Long-term Trends of Summer Season of Water Quality in Lake Doam.

2013 ◽  
Vol 46 (1) ◽  
pp. 128-134 ◽  
Author(s):  
Sungjin Kwak ◽  
◽  
Bal DevBhattrai ◽  
Changkeun Lee ◽  
Woomyung Heo
Keyword(s):  
Water Quality ◽  
Summer Season ◽  
Long Term Trends

scholarly journals Long-term trends, current status, and transitions of water quality in Chesapeake Bay

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Lawrence W. Harding ◽  
Michael E. Mallonee ◽  
Elgin S. Perry ◽  
W. David Miller ◽  
Jason E. Adolf ◽  
...  
Keyword(s):  
Water Quality ◽  
Chesapeake Bay ◽  
Current Status ◽  
Long Term Trends

scholarly journals Periods of Extreme Shallow Depth Hinder but Do Not Stop Long-Term Improvements of Water Quality in Lake Apopka, Florida (USA)

Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 538 ◽  
Author(s):  
Gaohua Ji ◽  
Karl Havens
Keyword(s):  
Water Quality ◽  
Eutrophic Lake ◽  
Water Levels ◽  
Shallow Depth ◽  
Benthivorous Fish ◽  
Chl A ◽  
Lake Apopka ◽  
Toxic Cyanobacteria ◽  
Long Term Trends

We recently documented that during times of extreme shallow depth, there are severe effects on the water quality of one of the largest shallow lakes in the southeastern USA—Lake Apopka. During those times, total phosphorus (TP), total nitrogen (TN), chlorophyll-a (Chl-a) and toxic cyanobacteria blooms increase, and Secchi transparency (SD) declines. The lake recovers when water levels rise in subsequent years. In this paper, we determined whether extreme shallow depth events, particularly when they re-occur frequently, can stop the long-term recovery of a shallow eutrophic lake undergoing nutrient reduction programs. Apopka is an ideal location for this case study because the State of Florida has spent over 200 million USD in order to reduce the inputs of P to the lake, to build large filter marshes to treat the water, and to remove large quantities of benthivorous fish that contribute to internal P loading. We obtained data from 1985 to 2018, a period that had relatively stable water levels for nearly 15 years, and then three successive periods of extreme shallow depth, and we examined the long-term trends in TP, TN, Chl-a, and SD. There were significant decreasing trends in all of these water quality variables, and even though water quality deteriorated during periods of extreme shallow depth, and reduced the slope of the long-term trends, it did not stop the recovery. However, in the future, if climate change leads to more frequent shallow depth events, which in lakes such as Apopka, result in the concentration of water and nutrients, it is unclear whether the resilience we document here will continue, vs. the lake not responding to further nutrient input reductions.

scholarly journals Long-term trends in water quality in an under-populated watershed and influence of precipitation

2009 ◽  
Vol 7 (4) ◽  
pp. 293-306 ◽  
Author(s):  
Ikuo TAKEDA ◽  
Akira FUKUSHIMA ◽  
Hiroaki SOMURA
Keyword(s):  
Water Quality ◽  
Long Term Trends

Analysis of Long-Term Trends in Lake Water Quality Observations

2012 ◽  
Vol 12 (1) ◽  
pp. 231-238 ◽  
Author(s):  
Eung Seok Kim ◽  
Jo Hee Yoon ◽  
Jae Woon Lee ◽  
Hyun Il Choi
Keyword(s):  
Water Quality ◽  
Lake Water ◽  
Lake Water Quality ◽  
Long Term Trends
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