Conservation Strategies

Effective freshwater conservation often requires the use of multiple complementary strategies. The most appropriate mix of strategies may depend on the scale of conservation significance of the ecosystem, as shown in Figure 2. Here we detail a subset of possible strategies, focusing on several with direct and more frequent applications to conserving freshwater biodiversity. Many additional strategies found in Figure 2 are addressed elsewhere.

Table 3 Water withdrawals for world regions, by sector

Region

Total (million m3) 2000

Per capita (m3 per person) 2000

Sector Withdrawals (%), 2000a Agriculture Industry

Domestic

Asia (excluding Middle East)

2147506

631

81

12

7

Europe

400266

581

33

52

15

Middle East and North Africa

324646

807

86

6

8

Sub-Saharan Africa

113 3e1

173

88

4

9

North America

525 267

1663

38

48

14

Central America and Caribbean

100657

603

75

6

18

South America

164429

474

68

12

19

Oceania

26187

900

72

10

18

Developed

1 221 192.0

956

46

40

14

Developing

2 583 916.4

545

81

11

8

Global

3802 320

633

70

20

10

aSectoral withdrawal data may not sum to one hundred because of rounding. Source: World Resources Institute, EarthTrends Freshwater Resources 2005.

aSectoral withdrawal data may not sum to one hundred because of rounding. Source: World Resources Institute, EarthTrends Freshwater Resources 2005.

Scale of conservation significance

Scale of conservation significance x-

Local/ sub-river basin i services \

Strategies for conserving freshwater ecosystems across scales of conservation significance

Note: All freshwater ecosystems have conservation significance. Strategies are complementary and additive. Effectively conserving freshwater ecosystems of higher conservation significance relies upon strategies used for conserving ecosystems of lower significance.

Local/ sub-river basin i services \

Strategies for conserving freshwater ecosystems across scales of conservation significance

Note: All freshwater ecosystems have conservation significance. Strategies are complementary and additive. Effectively conserving freshwater ecosystems of higher conservation significance relies upon strategies used for conserving ecosystems of lower significance.

Figure 2 Strategies for conserving freshwater ecosystems. Modified with permission from Blanch SJ (2006) Securing Australia's natural water infrastructure assets. Solutions for protecting high conservation value aquatic ecosystems. A proposal. Sydney: WWF-Australia.

Integrated Water Resources Management and Integrated River Basin Management

The concept of integrated water resources management (IWRM) is based on the interconnected nature of water bodies across landscapes, as well as along the river corridor from headwaters to the coast. IWRM promotes the need for participatory planning and implementation processes that bring stakeholders together to determine how to meet society's long-term needs for water while maintaining essential ecological services and economic benefits. A particular adaptation of the principles of IWRM to a river or lake basin is known as integrated river basin management (IRBM). The IRBM approach advocates managing a river and its entire catchment as a single system, and coordinating all the user group activities that take place within this geographic unit.

One of the key elements of IRBM is that it follows the principles of the ecosystem approach. The ecosystem approach framework is based on the central concept of managing water resources as integral parts of the ecosystem, rather than just as a resource to be exploited without regard to the system that nurtures it. Under this approach, water managers must do more than just satisfy one or two key users, but instead accommodate the wide array of economic and social benefits that people derive from aquatic environments, such as recreation, transportation, local livelihoods, cultural identity, and so on. The practical effect of this is that it widens the group of users who have a legitimate say in how the resource is managed.

Applying the ecosystem approach to managing water would ensure, at least in theory, that all goods and services derived from ecosystems, including inherent ecological functions, are taken into account when assessing development plans for a given river or lake. But despite the commitment by many countries to implement IWRM and IRBM approaches, such plans are still in their infancy. In most river basins around the world, allocation of water for irrigation and hydropower continues to take precedence over other water uses, as countries prioritize food and electricity production. Part of the problem is that implementing an IRBM approach requires different legal and institutional frameworks that go beyond our existing national government agencies. It requires cross-sectoral collaboration, and at times, new institutions, such as river basin organizations (RBOs), which link adjacent states along the river corridor in a legal framework that allows for the cooperative management of water resources within a single basin. RBOs can provide a forum for dialogue where the wide array of stakeholders can participate. As a result, development plans and water-use strategies can become more balanced, minimizing environmental and social impacts. For RBOs to be effective, however, they need to be given the authority, funding, and legal mandate to implement long-term water management policies -something that to date has been the exception rather than the norm. They must also have the wide participation of riparian states. The success of such approaches, however, ultimately depends heavily on cooperative governance and political commitment, which unfortunately are still lacking in many parts of the world.

Environmental Flows

Water management laws share water among users, such as towns, agriculture, industry, and the environment. Changing the shares among different user groups is often contentious, particularly in arid areas or where existing water rights are infringed upon, but presents a key conservation opportunity by reserving water for ecosystems. Termed 'environmental flows,' water allocated for ecosystems protects or reinstates key aspects of a river's flow. For example, pumping water may be restricted or prevented when river flows are low to allow aquatic organisms to move along a stream and allow wildlife to drink. Environmental flows do not just benefit the river channel but also floodplains, wetlands, estuaries, and coastal environments. These environments rely upon freshwater, sediments, nutrients, and carbon to be delivered from river channels. Small- and medium-sized floods may be protected from overextraction to ensure lateral hydrological connectivity between a river and its floodplain to allow wetlands to be refilled and fish species to migrate.

Groundwater-dependent ecosystems may be particularly dependent upon environmental flows, even if they occur at long distances from the river channel. Laws exist in some countries to legally protect water from being extracted, or to protect water that is specifically released from dams to maintain or recreate pulses and small floods. For example, environmental water reserves are guaranteed in water statutes in South Africa and the Australian state of Victoria to sustain river ecological functions.

Dams: Operation, Design, Removal

Building, operating, and removing dams, weirs, and barrages (collectively 'dams' for short) can affect river ecosystem function more than nearly any other set of activities. There are an estimated 45 000 large dams worldwide, and millions of small ones. In many parts of the world, new large dams are under construction or planned, especially for hydropower generation, whereas in a few countries like the United States, select dams are now being removed.

River ecology considerations should be fully incorporated into decision making about whether or not to dam a river, as recommended by the World Commission on Dams. For example, leaving the main-stem or large tributary of a river undammed will retain significant ecosystem benefits for river communities. Where dams are in place or under development, trying to mimic natural flow patterns as much as possible can recreate aspects of the flow regime that have been lost. Mitigating unnaturally warm or cold water discharges from dams is often needed to reestablish temperature regimes that trigger fish spawning and allow growth. For example, average water temperatures immediately below deep bottom-release dams in Australia's Murray-Darling Basin may be 5-10 °C cooler than natural. Building a multiple-level off-take at the dam wall allows dam managers to selectively draw surface water from the warmer epilimnion as dam levels rise and fall, thus warming river water below the dam, and hence increasing growth and survival of native warm-water fish.

Old, unsafe, or unnecessary dams can be removed to reinstate more natural flow patterns and permit freshwater organisms to move up and down a stream. Dam removal also reestablishes sediment transport regimes that continually erode and deposit sediments, thus continually creating new habitats. If removal is not feasible, a fish ladder or fish lift may be built to enable some fish and other freshwater animals to move upstream past dams, particularly during spawning migrations. Fish ladders and fish lifts are often poor alternatives to removal, however. They may not allow all fish species to use them, their effectiveness can be reduced by becoming blocked, and they require ongoing expensive maintenance.

Protected Areas

Protected areas - defined as 'areas of land and/or sea especially dedicated to the protection and maintenance of biological diversity, and of natural and associated cultural resources, and managed through legal or other effective means' - have received far less attention as tools for conserving freshwater species and habitats than they have for terrestrial and more recently marine features. Where protected areas have been used for freshwaters it has most frequently been through the establishment of Ramsar sites, identified under the Convention on Wetlands. Traditional protected areas have often been dismissed as ineffective for conserving freshwaters because of the connected and often linear nature of the systems. However, nontraditional protected areas, embedded within basin-wide integrated management efforts, are receiving increased attention. For example, riparian buffer zones can protect critical stream- or lake-side vegetation that filters pollutants, contributes organic material, moderates water temperatures, and provides woody debris for instream habitat. Floodplain reserves are in effect a special kind of riparian buffer zone, typically much wider and designed to protect the highly productive transitional areas that provide habitat to large numbers of both freshwater and terrestrial species. Fishery, or harvest, reserves are designed to provide spatial or temporal refuges for exploited freshwater species, so that populations can be sustainably fished over the long term; broader biodiversity conservation may be a secondary benefit. And protecting rivers as free-flowing, as described later, is a potentially powerful conservation tool gaining traction in certain countries.

Retaining Wild or Free-Flowing Rivers

Maintaining rivers without dams is arguably the single most effective river conservation strategy. Free-flowing rivers have been defined elsewhere as any river that flows undisturbed from its source to its mouth, either at the coast, an inland sea, or at the confluence with a larger river, without encountering any dams, weirs, or barrages and without being hemmed in by dykes or levees. Wild or free-flowing rivers allow water, sediment, nutrients, and biota to move longitudinally from the headwaters to the sea, terminal wetland or lake. Options for designating wild rivers are significantly reduced in most regions (Table 4), as only one-third of the world's large rivers remain free-flowing. But, some of the world's greatest rivers remain free-flowing along their mainstem, and sometimes on major tributaries too, including the Amazon, Oka-vango, Irawaddy, Sepik, and Mackenzie Rivers. No global free-flowing river conservation framework currently exists, although various countries have laws and programs to legally recognize and protect unim-pounded rivers. The United States' Wild and Scenic Rivers program protects reaches of over 150 rivers covering 11 000 miles from new dams and some other types of development, but other damaging catchment uses may not be regulated. Wild and Heritage rivers programs and laws also exist in Canada and in the Australian States of Queensland and Victoria.

Restoration

Freshwater restoration involves recreating key features of a stream's ecological processes that have been impaired or lost, and potentially reintroducing species that have become locally extinct. The profession of stream restoration has developed significantly in recent decades, with investments in restoration by communities, industries, and governments totaling billions of dollars annually. Restoration techniques are many and varied. For example, fencing out stock and revegetating riparian zones with indigenous plants helps filter nutrients, reduce erosion, improve habitat, and shade the water. Reintroducing rare and endangered species to streams from which they have disappeared may achieve high community support and serve to raise the profile of stream restoration more broadly, but will only be effective if the threatening processes that drove the species extinct in the first place have been mitigated or stopped. Relatively drastic restoration techniques are sometimes the only realistic option for highly degraded streams. Bulldozers may be required to remove contaminated sediments that pose an ongoing risk to human health or ecosystems. Formerly channelized streams with low habitat and biodiversity value may have meander bends and rock bars added back. Similarly, logs may be put back into streams after decades of desnagging for navigation to reproduce the eddies and submerged habitats that fish and invertebrates need.

Table 4 Regional distribution of rivers longer than 1000 km and percentage of rivers remaining free-flowing

Region Number of large rivers Percent free-flowing Example of free-flowing rivers

Table 4 Regional distribution of rivers longer than 1000 km and percentage of rivers remaining free-flowing

Region Number of large rivers Percent free-flowing Example of free-flowing rivers

Australia/Pacific

7

43

Cooper Creek, Sepik, Fly

Europe (west of Urals)

18

28

Oka, Pechora, Vychegda

Africa

23

35

Chari, Rufiji, Okavango

North America

33

18

Fraser, Mackenzie, Liard

South America

37

54

Amazon, Orinoco, Beni

Asia

59

37

Lena, Amur, Brahmaputra

Modified with permission from WWF (2006) Free-Flowing Rivers. Economic Luxury or Ecological Necessity? Zeist: WWF.

Modified with permission from WWF (2006) Free-Flowing Rivers. Economic Luxury or Ecological Necessity? Zeist: WWF.

Convention Programs of Work

No single comprehensive international convention currently exists for the conservation and sustainable use of freshwater ecosystems. Rather, global efforts are primarily underpinned by two global conventions, namely the Convention on Wetlands (Ramsar) and the Convention on Biological Diversity, plus a host of transboundary watercourse agreements and widely espoused best management principles. The Convention on Wetlands commits signatory nations to the wise use of all wetlands, the designation of wetlands of international importance, and international cooperation. The Convention's definition of a wetland is very broad and provides a basis for providing some form of conservation for all forms of freshwater and coastal ecosystems. Ramsar sites arguably form the world's largest network of conserved aquatic ecosystems with 1650 sites covering 150 million ha of freshwater and some coastal systems globally as of April 2007, although effective legal protection and on-ground management is lacking for many.

The Convention on Biological Diversity's Programme of Works on Inland Waters and Programme of Work on Protected Areas have goals and actions regarding protecting representative types of freshwater ecosystems within IRBM. Formal cooperation exists between these two Conventions to harmonize global efforts on the conservation of freshwater ecosystems. The United Nations Convention on the Law of the Non-Navigational Uses of International Watercourses contains commitments relevant to freshwater conservation, such as protecting ecosystems, but has not been ratified by enough countries to come into force legally. Notwithstanding, tra-nsboundary watercourse agreements have been negotiated for many river basins and provide a framework, at least on paper, for freshwater ecosystem conservation.

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