WATER QUALITY MANAGEMENT IN CONNECTED CATCHMENT- SHALLOW LAKE SYSTEMS - Integrating GIS, Remote Sensing, and Mathematical Modelling for Surface Water Quality Management - page 39

2.6. WATER QUALITY MANAGEMENT : TRENDS AND ISSUES

As earlier above, the movement of freshwater is facilitated by the hydrological cycle (including floods
and droughts) which demonstrates that water is inextricably linked with the environment. This implies
that actions in the environment, and more specifically the catchment/watershed, impact on water
resources. Similarly, water impacts on the environment. However the very nature of water is such that
its characteristics vary in both quantity and quality in time and space. The quality of water itself is a
significant factor to the limits on the amount of available water that may be used for various purposes.

What nature provides as available quantities may be reduced if the quality of water does not permit its
use for a specific purpose. This leads to additional costs in the development of the water resource to
meet both quantity and quality requirements needed for the particular use. Thus water quality directly
affects the quantity of water that can be employed for various purposes. The rapid growth of
population and urban communities and industrial and agricultural activities has significantly
contributed to the deterioration of water quality of lakes, rivers, groundwater and coastal waters
worldwide. Pollution of the environment including its freshwater resources is the result of human
society's activities. Also the use of water results in its degradation. Often this is incremental and
contamination results through repeated use.

It is expected that with economic development in the coming years, there will be a substantial increase
of water demand and therefore an increase of pollution discharge, if measures are taken. Already as
populations and economic activities grow many countries are rapidly reaching conditions of water
scarcity or facing limits to economic development. The widespread scarcity, gradual degradation, and
pollution of freshwater resources in many regions of the world, along with the encroachment of
incompatible activities, demand integrated water resources planning and management. It is therefore
of great importance that freshwater as a finite and vulnerable resource should be managed holistically
taking into consideration the integration of sectoral water plans and programmes within the framework
of national economic and social policy. Management must also recognize the interconnection between
water bodies and of the elements related to freshwater and freshwater quality.

Water quality management deals with all aspects of water quality problems relating to the many
beneficial uses of water. Water quality is a reflection or response of water composition to all inputs
and processes, whether natural or cultural. Water quality management should not be equated to water
pollution control which generally is the adequate treatment and disposal of wastewater. In the
definition of water quality management, water uses consist of intake, on-site, and in-stream flow uses.
Intake uses include water for domestic, agricultural and industrial purposes, or uses that remove water
from the source. On-site uses primarily refer to water consumed by swamps, wetlands, evaporation
from water bodies, natural vegetation, and unirrigated crops and wildlife. Flow uses include water for
estuaries, wastewater dilution, navigation, hydroelectric power production, and fish, wildlife and
recreation purposes. Water quality management serves to optimize water quality for all beneficial uses.
Implied in this, is that water should be managed so that use at any one location will not be detrimental
to its use at another location. In managing water quality, the factors and inputs that must be
considered, include both man-made sources and natural causes. With respect to water quality changes,
natural causes include geologic formations, vegetation, geographic factors and natural eutrophication.
Water quality is assessed by its physical, biological and chemical characteristics. Contamination can
alter one or all of these characteristics and may originate from point or from ambient sources. The
investigation and management of water resources systems for water quality must include consideration
and evaluation of;

(a) The physical, chemical and biological composition of headwaters and significant groundwater
discharges.
(b) Water quantity and quality requirements for all existing and potential water uses
(c) The means of water withdrawal and their effect on water quality and quantity
(d) The existing and future water and wastewater treatment technology used to alter water quality