INTRODUCTION TO INTRODUCTION TO ENVIRONMENTAL PROBLEMSENVIRONMENTAL PROBLEMS

SBP366E

Land Use & Integrated Watershed Management Land Use & Integrated Watershed Management

Definition of Terms

� The terms watershed, catchment, drainage area and river basin are all used to describe a land surface from which water flows downhill to a specified point on a watercourse.

� It is determined by topographical features which include a surrounding boundary or perimeter which is known as a drainage divide, beyond which water flows away into another catchment or catchments

Definition of Terms

� In North America, the term “watershed” is restricted sometimes to mean a comparatively small catchment, or sometimes to mean the upland, water-yielding portion of a larger river basin.

� In British Commonwealth countries it is sometimes restricted to mean “drainage divide”.

Integrated Watershed Management (IWM)

� Integrated watershed management can be defined as the coordinated, planned and sustainable management of the natural resources within a river basin.

� This approach to the management of land, water, vegetation and other natural resources seeks to maintain or enhance the quality of the catchment environment.

� All aimed at minimizing the adverse consequences of natural disaster events, to improve and enhance thequality of life of the catchment community by adopting a variety of physical, social and economic policies and techniques

Integrated Watershed Management

� Watersheds are naturally occurring units of the landscape, which contain a complex array of inter-linked and inter-dependent resources and activities, irrespective of political boundaries.

� A watershed can be perceived as an integrated ecological system, and its effective management requires the adoption of a systems approach in which the complex interrelationships between the development of natural resources, the integrity of the ecosystem, and the quality of the watershed environment have to be understood and accounted for.

Typical Land Use Planning Process

A typical model of integrated watershed development in the Republic of Korea

A flood in Cambodia

The planning process needs to observe the following principles:

(a) Adopt a holistic approach;(b) Recognize man as the focus of development;(c) Plan for multi-dimensional activities;(d) Seek qualitative and quantitative changes;and(e) Ensure equitable distribution and utilization of resources.

Strategies Towards Integrated Watershed Management Objectives

A Strategic Approach to Integrated Watershed Management

Objectives of an Integrated Watershed Management System

� Encourage proper management of the country’s resources, which include natural areas, forests, minerals, agricultural and urban lands, water and other resources

� Promote the social and economic welfare of the community

� Share the responsibility for environmental planning between all levels of government

� Provide opportunities for community involvement in planning

Core Functions of an Integrated Watershed Management System

� Inventory of land resource data

� Determination of specification for the establishment of conditions attached to the use of the land

� Development of strategies and priorities

� Coordination between organizations

Resource inventory requires the collection, analysis and presentation of data relating to all the land resources of the watershed, which can be expected to include the following components:

• Topography and landform• Geology and geomorphology• Soils• Climate, including data relating to rainfall, temperature,

evaporation, wind, insolation, etc.• Hydrology, including the quantity and quality of available

surface and sub-surface water resources• Vegetation cover, vegetation associations• Native fauna, including habitat survey

The results of a land system survey are presented in an integrated set of documents which will usually comprise:

(a) A map showing the land systems, with an extended legend detailing the principal environmental and climatic features of the area surveyed;(b) A description of each land system, including details of the principal features of each of the land facets identified within the system;(c) A textual account of each of the key factors of the environment surveyed, including geomorphology, climate, hydrology, soils and vegetation;(d) If appropriate, an evaluation or interpretation of the system in terms of its development potential or management possibilities.

Land Evaluation

Land evaluation is the process of assessing the potential of land for various alternative uses.

These may include productive uses, such as arable farming, livestock production or forestry, and uses that provide services or other kinds of benefits, such as water supply catchment, wildlife conservation, recreation or tourism.

Land evaluation is a key process in land-use planning and an essential feature of integrated watershed management practice.

Effective land-use planning can best be undertaken on the basis of a detailed assessment of the qualities of the land, a systematic evaluation of its potential for alternative uses and a rational set of decisions regarding the best uses for it.

Such planning is essential for effective watershed management

Land Evaluation

Land evaluation is essentially concerned with a comparison between the available resource qualities of the land and the requirements of different kinds of land use. Such evaluation requires information inputs from three sources: the land itself, the needs and effects of land uses, and economics.

Evaluation may be qualitative, quantitative in physical terms, or quantitative in monetary terms.

A qualitative evaluation is one in which the suitability of land for various alternative purposes is expressed in a qualitative way, using such terms as “highly suitable”, “marginally suitable”, “not suitable”, etc.

A quantitative physical evaluation is one which provides numerical estimates of the quantities of inputs and outputs associated with various land-use alternatives.

Land Capability ClassificationClass I: land suitable for regular cultivation where no special conservation measures are necessary;Class II: land suitable for regular cultivation but requiring simple (non-structural) soil conservation measures;Class III: land suitable for regular cultivation but requiring intensive soil conservation measures, such as graded banks and waterways;Class IV: land suitable for grazing and occasional cultivation; requires some non-structural erosion control measures. Class V: land suitable for grazing and occasional cultivation but requiring intensive (structural) soil conservation works;Class VI: land suitable for grazing only. Non-structural soil conservation measures required;Class VII: land which is steep, infertile, erosion prone or has shallow soils. Recommended use is green timber cover, some logging or grazing possible with good management controls;Class VIII: land which should not be cultivated, grazed or logged but set aside for such nonproductive purposes as nature conservation, recreation etc.