pollution was worsening in tributaries
because of high levels of nitrates and phosphates
that had already endangered drinking water in some areas.
He said an algal bloom from too many nutrients earlier this year on a tributary had contaminated drinking water for 50,000 people in Fengdu County.
Water quality - The quality of water can slowly deteriorate when it is stored in a reservoir as the water is
stagnant .Flowing river water maintains a constant supply of dissolved oxygen. Dissolved oxygen is
vitally needed to support aquatic flora and fauna, and to prevent some chemical reactions to pollute the
water. There are many numbers of factors that can reduce oxygen levels in a reservoir, for e.g. organic
material in the water can readily use up oxygen as it decomposes. The depth of the water in the
reservoir, temperature difference between the water at the top of the reservoir and the bottom and its
flow can also affect the oxygen levels. The type and the chemical nature of the land that is covered by
a reservoir may affect the water quality. Pesticides and other chemicals from farms and toxic materials
from industries can pollute the water. The streams and rivers flowing into the reservoir act as a major
source of pollution as they may be carrying pollutants. The designers of a reservoir and the dam have
to consider all these factors and whether if any of these factors will have an adverse effect on the
quality of the water. If the answer is yes, the designers need to include special safety measures to
maintain good quality of water.
Mr. Wang framed his speech like a call to action. He said officials needed to address environmental problems “at the root.” He warned that government agencies were not prepared for emergencies and had no plan for natural disasters like an earthquake. He declared that China would now “work hard to build a first-class hydropower project and to create a first-class environment.”