poster - International Conference of Agricultural Engineering

Variability of water quality in a lake receiving drainage water
from the Hetao irrigation system in the Yellow River basin,
China
Biao Sun 1 , Changyou Li 1 , Claudia M d S Cordovil 2 , Keli Jia 1 , Sheng Zhang 1 ,
Zhongyi Qu, Amarilis de Varennes 2 , and Luis S Pereira 2
1 College of Water Conservancy and Civil Engineering, Inner Mongolia Agricultural
University, Hohhot, 010018, PR China
2 CEER - Biosystems Engineering, Institute of Agronomy, Technical University of Lisbon,
Tapada da Ajuda, 1349-017 Lisbon, Portugal
* Email: lspereira@isa.utl.pt
Abstract
The Wuliangsuhai Lake is very important for the irrigation and drainage system of the
Hetao Area in China. Between 2005 and 2010,water quality of the lake was monitored
using physical, chemical and biological parameters. Chemical changes over time were
not significant while COD was affected by the building of a new tomato plant as well as
by a new Sewage Treatment Plant. To this day large amounts of organic industrial
wastewaters are discharged into the lake without any treatment affecting water quality.
Freezing of the lake during the cold season and flow direction affected several of the
parameters monitored.
Keywords: water quality dynamics, Irrigation, Wuliangsuhai Lake
1. Introduction
Awareness of an impending water crisis began in the 1970’s but it was only in the
1990’s that water eutrophication became a serious problem in China (Jingan and
Hongqing, 2002) affecting all economical activities dependent on freshwater quality. The
Northwest of China is an arid or semi-arid region, depending on water for local
economic development, namely water derived from the lakes. The Hetao Region is one
of the three largest agricultural regions in China (Yang and Liu, 2002), with an irrigated
area of about 5640 km 2 . Irrigation water comes mainly from the Yellow River (5 billion
m 3 ) and is discharged into the Wuliangsuhai Lake (WL) (Fig. 1). In Hetao, pesticides
and fertilizers were first used by the 1960’s. Rapid economic development led to an
increase of urban wastewater discharge (0.5 billion m 3 ) and agricultural runoff into the
WL from the upper channels (Wan, 2009). Currently, 1500 to 2000 tons of pesticides
and 600000 tons of fertilizers are used per year (Liu, 2004), impacting the quality of thw
WL water and compromising natural ecosystems. Groundwater quality of WL has been
studied before (Liu et al., 2010) but little is known about surface water quality in the
Hetao irrigation area. It is therefore urgent to identify polluting sources as well as the
available practices to mitigate euthrophication of the lakes.