Impacts of the South North Water Diversion on Nansi Lake, China

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Impacts of the South - North Water Diversion on Nansi Lake, China 

Tom DeBusk 

DB Environmental, Inc. 

Tom Goffinet 

Azurea, Inc. 

 

An ambitious engineering project, the South – North water transfer, is underway in China 

to provide the pumping and conveyance infrastructure for moving massive volumes of 

water from the Yangtze River to drought-prone areas in the north of the county.  Nansi 

Lake, a long (125 km), narrow water body (1270 km

2

 total area), will serve as a key 

conveyance segment for the eastern route of the water transfer project. Water quality in 

Nansi Lake is poor, due to internal (aquaculture) pollutant inputs and external (untreated 

domestic wastewater, industrial wastewaters, and agricultural and urban runoff) loadings 

from the 31,000 km

2

 watershed. The water transfer project is serving as a catalyst for 

eliminating and treating industrial and municipal discharges in the Nansi Lake watershed, 

as well as the implementation of water reuse schemes. Both conventional (WWTPs) and 

non-conventional water treatment technologies (constructed wetlands) are being deployed 

for reducing point source and non-point source pollutant loads. Spatial water quality 

trends demonstrate that pollutant loadings from aquaculture operations in the lake are 

substantial, however, and these are proving difficult to mitigate. Additionally, the water 

transfer itself may create problems, since it will change the dry season lake residence 

time, direction of flow, and water depths, potentially creating adverse impacts to biota as 

well as the ~70,000 humans (fisherman, fish farmers) who live in the lake.