Civil Engineering Reference
In-Depth Information
dependent on sustainable and properly functioning ecosystems which in turn
provide water security over the long term (UNEP 2009).
Figure 1.5 (see colour plates) illustrates a creek bank protected by riparian
vegetation from the intense rainy season flows and power boat wash. Without
such protection, fish habitat and recreational fishing and boating would be
diminished over time by silted up creeks.
Most OECD countries have addressed surface water pollution, mainly by
regulating industrial discharges and investing in urban sewage treatment.
The 'polluter pays' principle and source control have increasingly gained
support over technical end-of pipe solutions (Pahl-Wostl
et al
. 2008: 2). But,
according to Gurría (2009), diffuse pollution from agriculture (e.g. fertilisers,
pesticides and livestock manure) still remains a challenge. Nearly 60 million
tonnes of nitrogen are expected to reach coastal waters from inland sources by
2030, killing fish and disrupting ecosystems along the way. There is growing
awareness that the need for integrated approaches requires taking a range of
trade-offs into account and involving stakeholders in the whole management
process (Pahl-Wostl
et al
. 2008: 484).
Box 1.2: Ecosystem services offer benefits beyond the
environment
Ecosystem services can be delineated in four ways:
O
Provisioning services - the products from ecosystems such as food,
fresh water, timber and fuel, fibres and genetic resources;
O
Cultural - recreation, transport, ecotourism, spiritual, religious and
aesthetic uses, education, cultural heritage and a sense of place;
O
Regulation - climate regulation, flood alleviation, water purification,
and disease regulation;
O
Supporting - underlie the above, and include nutrient cycling, soil
formation and primary production (UNEP 2009: 10).
Major management options to address ecosystem functioning and
services include:
O
Maintaining environmental flows;
O
Pollution control;
O
Ecohydrology and phytoremediation;
O
Habitat rehabilitation;
O
Conjunctive use of surface and groundwater;
O
Watershed management;
O
Water demand management; and more recently
O
Payment for ecosystem goods and services (UNEP 2009: 18).
