Habitat loss

Certain activities, especially irregular settlements, will result in an imbalance between the legal regularization of land ownership and the protection of natural habitat.[2]​ The severity of the impact depends on the type of habitat to be converted, as well as the way in which the conversion is to be carried out. When wildlands, wetlands, tropical forests and other fragile ecosystems are involved, the environmental assessment team must carefully study the impacts, examine the alternatives considered, and perhaps propose new alternatives.[2]​.

Loss of soil productivity

Certain forest soils, when deprived of their natural cover, suffer lateralization or become prone to rapid erosion, becoming essentially unproductive. The removal of humus during leveling also reduces its productivity. The loss of soil due to erosion has the same effect, and can also degrade hydraulic resources. Another factor that profoundly alters the structural balance of the soil is its misuse, for example, supplying water for irrigation, without worrying about adequate drainage to allow the elimination of excess salt that accumulates in the soil, drastically reducing its fertility.

Conversion of high-quality agricultural land to urban uses also reduces its productivity.

Mitigating measures that an environmental assessment might recommend include:.

• - Avoid building on steep slopes.

• - Retain forest cover; gather and replace the humus.

• - Conserve prime quality agricultural land.

• - Apply good cultivation practices.

• - Control erosion and sedimentation through the use of manure and straw during construction.

• - Quickly replace the top vegetation layer on slopes.

• - Build sedimentation piles and straw barriers or filtration fabric to protect waterways.

Modified hydrology

Clearing, flattening, filling, paving, or building construction alters surface flow and seepage configurations.[7] Results include localized ponding and flooding, increased frequency or magnitude of flooding downstream, a drop in the water table, decreased groundwater recharge, and increased reduced flows in streams.

Management measures include design and construction techniques to maintain or replace local drainage channels, retention or detention structures to prevent an increase in inflow rate, measures to compensate for reduced filtration (porous pavement, filtration ponds, etc.); and the conservation of open spaces in critical aquifer recharge areas.[8]​.

Soil pollution

Soil can be contaminated through salinization if irrigation systems are not designed and operated correctly. It can be contaminated by the disposal of hazardous waste or inappropriate operation of solid waste and sewage disposal systems within the land, it is important to consider:

• - Potential environmental impact of irrigation and drainage projects.

• - Garbage disposal.

• - Wastewater.

Land clearing

In general, the impacts of land clearing are more significant in tropical regions than in temperate regions, because the former experience higher temperatures, which accelerate the chemical degradation of soils, and greater precipitation intensity, producing more severe erosion.

There are three basic methods that are often used in combination for the same project:

• - Manual methods: Felling or cutting the vegetation, a drying period, and then burning the waste.

• - Mechanical methods: The use of heavy equipment (e.g. bulldozers, heavy chains and tractors) to fell trees, cut and clear undergrowth; its accumulation in rows or piles, its burning and finally the cleaning of the waste.

• - Chemical methods: the use of herbicides to establish crop areas, leaving dead trees standing, cut down or burned.

Mechanical methods have significant adverse impacts, including the loss or inversion of humus, destruction of soil structure, and compaction resulting in increased runoff.[9]​.

Both mechanical and manual methods involve burning, which often reduces soil nutrient content and the activity of beneficial organisms, and contributes to high atmospheric concentrations of carbon dioxide.

Chemical techniques have been shown to have less harmful effects on the soil, however, the long-range effects of herbicide use in the tropics are not well known.

Inappropriate post-clearance management practices, such as failure to manure the land, failure to employ soil conservation practices, and repeated burning, have often resulted in the reduction of soil fertility to the point where economic agricultural production cannot be sustained. Abandonment and infestation of forests are the final results.

World Bank - Technical Work Number 139. Reference Book for Environmental Assessment.

• - Volume I - Policies, Procedures and Intersectoral Problems.

• - Volume II - Sectoral Guidelines.

• - Volume III - Energy and Industrial Projects.

Environment Department - World Bank - Washington, D.C (The Spanish version had the technical collaboration of the Pro Tempore Secretariat of the Amazon Cooperation Treaty, and the financial support of the Environment Department of the Inter-American Development Bank, the Economic Development Institute of the World Bank, the Environment Technical Division for Latin America of the World Bank and the Canadian International Development Agency).

• - Wikibooks in Spanish houses notes on management of land and water resources.

Habitat loss

Certain activities, especially irregular settlements, will result in an imbalance between the legal regularization of land ownership and the protection of natural habitat.[2]​ The severity of the impact depends on the type of habitat to be converted, as well as the way in which the conversion is to be carried out. When wildlands, wetlands, tropical forests and other fragile ecosystems are involved, the environmental assessment team must carefully study the impacts, examine the alternatives considered, and perhaps propose new alternatives.[2]​.

Loss of soil productivity

Certain forest soils, when deprived of their natural cover, suffer lateralization or become prone to rapid erosion, becoming essentially unproductive. The removal of humus during leveling also reduces its productivity. The loss of soil due to erosion has the same effect, and can also degrade hydraulic resources. Another factor that profoundly alters the structural balance of the soil is its misuse, for example, supplying water for irrigation, without worrying about adequate drainage to allow the elimination of excess salt that accumulates in the soil, drastically reducing its fertility.

Conversion of high-quality agricultural land to urban uses also reduces its productivity.

Mitigating measures that an environmental assessment might recommend include:.

• - Avoid building on steep slopes.

• - Retain forest cover; gather and replace the humus.

• - Conserve prime quality agricultural land.

• - Apply good cultivation practices.

• - Control erosion and sedimentation through the use of manure and straw during construction.

• - Quickly replace the top vegetation layer on slopes.

• - Build sedimentation piles and straw barriers or filtration fabric to protect waterways.

Modified hydrology

Clearing, flattening, filling, paving, or building construction alters surface flow and seepage configurations.[7] Results include localized ponding and flooding, increased frequency or magnitude of flooding downstream, a drop in the water table, decreased groundwater recharge, and increased reduced flows in streams.

Management measures include design and construction techniques to maintain or replace local drainage channels, retention or detention structures to prevent an increase in inflow rate, measures to compensate for reduced filtration (porous pavement, filtration ponds, etc.); and the conservation of open spaces in critical aquifer recharge areas.[8]​.

Soil pollution

Soil can be contaminated through salinization if irrigation systems are not designed and operated correctly. It can be contaminated by the disposal of hazardous waste or inappropriate operation of solid waste and sewage disposal systems within the land, it is important to consider:

• - Potential environmental impact of irrigation and drainage projects.

• - Garbage disposal.

• - Wastewater.

Land clearing

In general, the impacts of land clearing are more significant in tropical regions than in temperate regions, because the former experience higher temperatures, which accelerate the chemical degradation of soils, and greater precipitation intensity, producing more severe erosion.

There are three basic methods that are often used in combination for the same project:

• - Manual methods: Felling or cutting the vegetation, a drying period, and then burning the waste.

• - Mechanical methods: The use of heavy equipment (e.g. bulldozers, heavy chains and tractors) to fell trees, cut and clear undergrowth; its accumulation in rows or piles, its burning and finally the cleaning of the waste.

• - Chemical methods: the use of herbicides to establish crop areas, leaving dead trees standing, cut down or burned.

Mechanical methods have significant adverse impacts, including the loss or inversion of humus, destruction of soil structure, and compaction resulting in increased runoff.[9]​.

Both mechanical and manual methods involve burning, which often reduces soil nutrient content and the activity of beneficial organisms, and contributes to high atmospheric concentrations of carbon dioxide.

Chemical techniques have been shown to have less harmful effects on the soil, however, the long-range effects of herbicide use in the tropics are not well known.

Inappropriate post-clearance management practices, such as failure to manure the land, failure to employ soil conservation practices, and repeated burning, have often resulted in the reduction of soil fertility to the point where economic agricultural production cannot be sustained. Abandonment and infestation of forests are the final results.

World Bank - Technical Work Number 139. Reference Book for Environmental Assessment.

• - Volume I - Policies, Procedures and Intersectoral Problems.

• - Volume II - Sectoral Guidelines.

• - Volume III - Energy and Industrial Projects.

Environment Department - World Bank - Washington, D.C (The Spanish version had the technical collaboration of the Pro Tempore Secretariat of the Amazon Cooperation Treaty, and the financial support of the Environment Department of the Inter-American Development Bank, the Economic Development Institute of the World Bank, the Environment Technical Division for Latin America of the World Bank and the Canadian International Development Agency).

• - Wikibooks in Spanish houses notes on management of land and water resources.