Introduction - Hydrologic Time Series Analysis: Theory and Practice - page 3

affect the availability and distribution of rainfall, snowmelt, river flows and
groundwater, and deteriorate water quality, which in turn can have severe
impacts on both urban and rural regions of the world (IPCC, 2007). Climate
change is considered as a major challenge to the efficient management of
natural resources and a barrier to the transition from poverty to prosperity
(UNDP, 2007). Thus, in the beginning of the 21 st century, we are bound to
face the stark reality that the current patterns of water development and
consumption are not sustainable in several countries of the world. Therefore,
there is an urgent need for widespread realization that freshwater is a finite
and vulnerable resource, which must be used efficiently, equitably and in an
ecologically sound manner for present and future generations to ensure
sustainable development on the earth.
Inadequate water resource systems reflect failures in planning, management
and decision making not only in the water sector but also in other sectors of
society directly or indirectly dependent on water. It is the need of the hour for
scientists/engineers as well as for planners and decision makers to efficiently
plan, develop, operate and manage water resource systems so as to ensure
adequate, cost-effective, good-quality and sustainable supply of water for
humans and nature (Falkenmark and Rockstrom, 2004; Loucks and van Beek,
2005; Grafton and Hussey, 2011). The complex and deep interactions that
have existed between humans and water systems throughout the human history
need to be understood by modern scientists/engineers, planners and decision
makers (Postel and Richter, 2003). It is also essential to recognize that unlike
much basic economic theory, the goods and services provided by ecosystems
are not at all substitutable and ecosystems cannot easily be replaced by
technology (Kaufmann, 1995). At this point in human evolution, it is vital that
people understand the crucial link between human welfare and ecosystem
well-being (Arrow et al., 1995; UNESCO, 2003, 2009), and institutions must
be strengthened to support effective water governance (Walker, 2009). Natural
scientists and social scientists need to work together to better understand
human-environment interactions (IPCC, 2001) as well as to bridge the growing
knowledge gap between water management and ecology. More and more
research is needed to predict how potential ecosystem perturbations may
affect short- and long-term ecosystem functionality. Given the dynamic and
evolving nature of ecosystems, a major technical challenge is quantifying
how much the ability of ecosystems to meet human needs is changing over
time.
Today, one of the biggest challenges is how we can effectively balance
freshwater for human development and ecosystems welfare in achieving equity,
environmental sustainability, and economic efficiency in the face of looming
global climate change. Quantitative analysis using statistical and mathematical
modelling tools as well as modern information technologies such as remote
sensing, GIS, decision support system, expert system, etc. can support and
improve water resources planning and management (Loucks and van Beek,