Retreating rate estimation of the fertile alluvial soils in the nile delta under the urban encroachment by using remote sensing data and gis technique

الملخص EN

The area under study is situated in the Nile Delta as represented by Toukh district (Markaz), Qalubiyah province.

The urban change detection was based on the spectral signatures of satellite SPOT-4 data that were acquired in each year of 1995 and 2007.

The satellite data were visually interpreted to specify the physiographic units for evaluating their denatured land.

The associated soils were classified and evaluated according to the systems of Soil Taxonomy and Land Evaluation respectively.

The change detection cleared that the urban encroachment denatured fertile alluvial soils, which cannot be easily developed in the newly reclaimed areas even with a high capital intensity and daily expensive energy.

These valued retreated fertile Nile alluvial soils represent unique physiographic-soil characteristics of highly suitable soils (S1) for the irrigated agriculture.

These soils could be classified as Typic Haplotorrerts, clayey, locally Leptic Haplotorrerts, clayey over fine loamy in the deltaic alluvial plain; Typic Torriorthents, fine loamy, locally fine loamy over coarse loamy in the levees; Typic Torriorthents, coarse loamy over sandy in the point bars and reworked parts of sub-deltaic outcrops; Typic Torriorthents sandy in the sub-deltaic outcrops.

The soils developed in the alluvial deltaic plain (dominant unit) were evaluated for specific crops of the common cultivated ones as herbaceous crops (mainly cotton) and trees (mainly citrus).

These soils are categorized as highly suitable class (S1).

The value of these Nile alluvial soils also based on the profitable specific quality of cotton "extra-long staple” that was highly adapted with their soil characteristics.

This value is negatively affected, being the urbanization is mainly acting on the annually cultivated area, which loosed 3304.9 sedans from the year 1995 t0 2007.

This annual cultivation is dominated by cotton crop of specific quality that cannot be shifted to the newly reclaimed lands, otherwise it will be collapse.

The cotton quantitative quality for exports, ginning, and spinning and textile industries will be badly affected under this urban encroachment.

Rather high unique value is the sit and situation of the studied area as the local skilled agriculture labor and being centrally situated in Egypt with intensive spidery infra-structure network, extending to the other regions.

Monitoring the retreated fertile land in the studied area indicated that, in the year of 1995, about 3681.2 feddans or 1546.1 hectares of the total area (55127.5 feddans or 23153.0 hectares) were urbanized, and then the urban area increase to about 6350.1 feddans or 2666.9 hectares in the year 2007, denaturing about 2668.9 feddans or 1120.9 hectares were loosed through 12 years from the residual cropped lands in 1995.

Thus, the rate of the urban encroachment was assessed as 222.4 feddans or 93.4 hectares per year.

If this flurried urban encroachment trend is ceaselessly continues, the duration of entire loss of this fertile cultivated land can be estimated as 197 years.

This situation may be more serious in another scanned area under more flurried attack.

Hence the cultivated lands in the Nile Delta will be most probably entirely denatured as the integration of time-urbanization encroachment and their demographic attributes will be in turn deformed.

Accordingly, it is a call for keeping the lands of the Nile alluvium as a protectorate.