Watershed Management Objectives and Practices

Watershed Management Objectives and Practices

• Eradicate pervasive poverty
• Improve conservation of soil, water, and other natural resources including biodiversity
• Promote more equitable sharing of benefits and costs
• Promote active involvement of local communities and other key stakeholders
• Facilitate development of mutually beneficial arrangements among stakeholders
• Promote an orderly and less damaging use of land and other natural resources
• Set in place institutional mechanisms that will guarantee sustainability of watershed management projects

Dealing with Realities of Watershed Management

• Multiple demands on watersheds
• Multiple land uses and users
• Multiple LGUs having jurisdiction over parts of a watershed
• Multiple ecosystems that are sensitive to human activities

Watershed Functions and Uses

• Watersheds have multiple functions and uses
• Rare to find a watershed that is withdrawn from other uses due to limited land resources and growing population
• Managers task is to regulate use of watershed, not prohibit it, to ensure sustainability of soil, water, biodiversity, and ecosystem services

Watershed Management Practices

Watershed Characterization

• Process of describing watershed features using qualitative and quantitative methods
• Main goal is to understand why the watershed is behaving in a certain way
• Outputs are bases for designing solutions to address problems, designing development interventions, and monitoring and evaluation systems

Definition of Terms and Basic Concepts

Watershed

• Topographically delineated area drained by a river system with a single outlet
• Natural landscape with natural boundaries
• Main function is to capture rainwater ideally for storage underground
• Rainwater that is not stored is drained by streams through one outlet draining to a larger watershed or to a lake, wetland, or sea

Watershed Boundary

• Topographic boundary or barrier such as a ridge, hill or mountain, known as a divide
• Determines the portion of rainwater going to adjacent watersheds

Streams in Watersheds

• A watershed is made up of a stream network with one mainstream
• All streams from all subwatersheds flow into the mainstream that carries all water to the outlet
• Ephemeral streams have water only when it rains
• Intermittent streams have water only during rainy or wet season
• Perennial streams have water all year round

Subwatersheds

• A watershed is made up of many smaller watersheds called subwatersheds
• A subwatershed drains its water to the larger watershed
• The smallest subwatershed is one that has only one unbranched stream, called a First Order Stream

Micro Catchments to River Basins

• Micro catchment: <1,000 ha
• Small watershed: 1,000 ha to 10,000 ha
• Medium watershed: 10,000 ha to 50,000 ha
• Large watershed: 50,000 ha to 100,000 ha
• River basin: >100,000 ha

Importance of Watersheds

• Capture rainwater for storage underground
• Provide ecosystem services
• Interconnectivities of ecosystems in a watershed
• Change in one ecosystem triggers changes in other ecosystems