Land Degradation in the Nile Delta

Abstract

The cultivated area of the Nile Delta is 4.354 million feddan (1 feddan equals 4,200 m² or 0.42 ha), 93% of which are old dark lands of alluvial soils that have a texture which ranges from heavy clayey to clay. This area represents 71.6% of the total old alluvial land in Egypt (6 million feddan) and 55.5% of the total officially cultivated lands (8.6 million feddan). Salinity, water logging, and seawater intrusion in addition to pollution, nutrient depletion, and population encroachment are the most common predominant factors affecting the land degradation in the delta. There are only three main sources of hazardous salts in Nile Delta soils, irrigation water, shallow water table and water logging, and the seawater intrusion to the water table and surface soils. The Nile River and its irrigation canals work in the Nile valley as both irrigation and drainage canals at the same time, but the Nile Delta is covered with a good net of drainage canals that collect about 15 BCM a year that are reused in irrigation at a volume of 10 BCM. The drain in the delta area receives all kinds of pollutants such as sanitary and industrial wastes in addition to the residues of pesticides and nitrogen fertilizers used in cultivated soils. The reused drainage water becomes one of the main causes of land degradation and soil contamination in the delta region. Saline, saline-sodic, and sodic soils represent approximately 33% of the delta soils; the residual areas are in real threats due to the buildup of soil salinity. Urban sprawl is one of the main problems that threaten the limited highly fertile land in the Nile Delta. Land encroachment in the Nile Delta caused Egypt to lose about 740,000 feddan over the last 38 years.

Glossary

Agricultural water use

Agricultural water use includes water abstracted from surface and groundwater and return flows (withdrawals) from irrigation for some countries but excludes precipitation directly onto agricultural land.

Brackish water

Water where the salinity is appreciable but not at a constant high level. The salinity may be subject to considerable variation due to the influx of fresh or seawaters.

Climate change (IPCC)

A change in the state of the climate that can be identified (e.g., by using statistical tests) by changes in the mean and/or the variability of its properties and that persists for an extended period, typically decades or longer.

Drip irrigation

A water-saving technique of surface irrigation through pipes made of plastic. The process delivers the water drop-by-drop to plants through tiny holes and prevents waterlogging of soils.

Drought (UNCCD)

A naturally occurring phenomenon that exists when precipitation has been significantly below normal recorded levels, causing serious hydrological imbalances that adversely affect land resource production systems.

Drylands (MEA)

Areas with an aridity index value of less than 0.65—that is, areas in which annual mean potential evapotranspiration is at least 1.5 times greater than annual mean precipitation.

Freshwater

Any water source excluding sea and brackish waters.

Freshwater ecosystems

The abiotic (physical and chemical) and biotic components, habitats, and ecological processes contained within water bodies and their fringing vegetation, but excluding marine and estuarine systems.

Fecal indicator

A group of organisms that indicate the presence of fecal contamination, such as the bacterial group thermotolerant coliforms or E. coli. Hence, indicators only imply that pathogens may be present.

Irrigation

The artificial application of water to land to assist in the growing of crops and pastures. It is performed by spraying water under pressure (spray irrigation) or by pumping water onto the land (flood irrigation).

Recycled water

This is a generic term for used water that is recovered and supplied again for beneficial uses. Water can be recycled from rainwater, storm water, gray water, and treated effluent. When these alternative sources are treated as required, the water is suitable for a range of purposes (Recycled Water in Australia 2015). For example, drainage water may be used several times as is the case in Egypt.

Reused water

Treated wastewater, gray water, or storm water runoff, recovered to a quality suitable for beneficial use.

Wastewater

Liquid waste discharged from homes, commercial premises, and similar sources to individual disposal systems or to municipal sewer pipes, which contains mainly human excreta and used water. When produced mainly by household and commercial activities, it is called domestic or municipal wastewater or domestic sewage. In this context, domestic sewage does not contain industrial effluents at levels that could pose threats to the functioning of the sewerage system, treatment plant, public health, or the environment.

Water quality criterion

Numerical concentration or narrative statement recommended to support and maintain a designated water use. This includes providing basic scientific information about the effects of water pollutants on a specific water use.

Water quality objective (synonyms: water quality goal or target)

A numerical concentration or narrative statement that has been established to support and to protect the designated uses of water at a specific site, river basin, or part(s) thereof. This takes into consideration a water quality criterion and a critical assessment of national priorities. A water quality objective is therefore a management decision and not a scientific statement. Objectives can be stated in policy documents, but they can also be established in laws or regulations, especially to be attained at a future specified date.

Water quality standard

An objective that is recognized as mandatory. Normally these would be established in a law or probably a regulation. However, it is possible to establish binding standards in a policy document, which is then enforced through some other means. The term is used in this compendium more broadly, to designate a general water quality rule that can be binding for users (when established by law or regulation) or nonbinding (as when established by policy—for instance in guidelines—in which case their purpose is aspirational).

Water use

Use of water by agriculture, industry, energy production, and households, including in-stream uses such as fishing, recreation, transportation, and waste disposal.