- Email: [email protected]
In favour of the Aswan High Dam
Short Communications
291
has been readily forthcoming. Its activities have been schemes in Africa. The Sennar Dam, which was carried out on an essentially personal basis, and the inaugurated in 1925 to irrigate the large Gezira Scheme apellation 'The CIPO family' is a realistic description. for cotton production, resulted in the spread of bilharziasis among Sudanese peasants in the Gezira. PHYLLIS BARCLAY-SMITH, The Roseires (Fig. 1), Kariba, and Volta, Dams were Secretary-General, International Council for Bird Preservation, c/o British Museum (Natural History), Cromwell Road, London S W 7 , England
IN FAVOUR OF THE ASWAN HIGH DAM
With the growth of ecological literature in the past decade, the Aswan High Dam of Egypt is becoming, in the writings of a number of ecologists, something of a 'classical' textbook example of an ecological misdeed. In textbooks, popular accounts, proceedings of conferences, etc., one finds the High Dam commonly mentioned in this context. Except for a few eminent ecologists, who perceive the merits of the High Dam for what they are, many authors are apt to overlook the positive side of this large-scale project. The origins of this largely negative attitude cannot be disentangled from the international situation which beset the financing and construction of the High D a m - - a situation that is too well known to need recounting here. Several of the newspapers which stressed the negative sides of the project at that time did not appear to have considered the real welfare of the Egyptian people. Yet it should not be forgotten that these negative sides are not peculiar to the High Dam; hundreds of dams are built throughout the world, but it seems to be mainly the Aswan High Dam that is expressly chosen for horror-stories. When ecology and conservation became subjects to be written about profusely for the scientific community and the general public, some ecologists were led to believe that the widespread press material about the High Dam could be taken as a ready example of an ecological disaster. For 'disaster' is the description actually used in more than one respectable text on ecology. Let us consider soberly the principal negative effects of the Aswan High Dam which are recurrently mentioned. They boil down to the spread of bilharziasis, silting, and the depletion of the Mediterranean sardine fisheries. In addition, it is alleged that the Dam will not help to increase food production enough to feed the number of people who were added to the population during the Dam's construction period. We will now deal with each of these objections in turn. The spread of bilharziasis follows all large irrigation
Fig. 1.
The Roseires Dam which is holding back almost half of the silt carried by the Blue Nile.
built more or less contemporaneously with the Aswan High Dam, yet the health hazards associated with them are given brief mention--sometimes in connection with the High Dam just in order to emphasize the latter's presumed hazards. Already before the Dam was built, up to 90 per cent of the rural population in some areas of Egypt suffered from bilharziasis. The Ministry of Health took immediate measures to control the disease in the Aswan, Qena, and Sohag, Governorates downstream from the Dam when the incidence of the disease was noted to rise. These measures include the establishment of rural health service units to serve every village having a population of more than 5,000. Piped water is now within reach of 85 per cent of the population of Egypt. The new irrigation canals are dug in straight lines, are lined with limestone blocks, and have their aquatic weeds dredged out to deprive snails of suitable breedinggrounds. Actually, the control of bilharziasis is a complicated problem associated with several factors, among which are the standard of living of the peasant, his social and cultural make-up, and his clinging to some unhygienic habits which are encouraged by the prevalent methods of irrigation. Whatever the means by which bilharziasis is to be eventually controlled, the High Dam and Egypt's growing population could not possibly wait for this control to materialize. The problem of silting in Lake Nasser--which has developed by flooding the reaches of Lower Nubia-can, from the following data, be easily understood to be much exaggerated. The present yearly amount of silt in the Blue Nile passing at Khartoum after the
292
Biological Conservation
construction of the Roseires Dam is 55 million tons. of Egypt and indeed of the world. Let us, instead, If the specific gravity of silt is taken as 1.5, the total discuss more fruitfully the means to nullify the negative volume of this silt would be 37 million m 3. As the effects of all projects destined for human welfare and storage capacity of Lake Nasser is 130 thousand let us maintain balanced approaches that will convince million m 3, the time it would take to silt up only policy-makers and the general public that wise one-fifth of its volume would be seven hundred years. environmental considerations are associated with Almost all the silt is now laid down at the southern long-term benefits. This is the message of ecological end of the Lake. In future, this deposited silt could sciences. ultimately be dredged and spread over arable l a n d - SAMIR I. GHABBOUR, with great benefit to crops, if a feasible method could Department of Natural Resources, be developed for this. Alternatively, it could add Institute of African Research and Studies, valuable new land for agriculture, thus repeating University of Cairo, the story of the Fayoum depression which was used 33 Misaha Street, Dokki, Giza, Egypt. as a reservoir, presumably in the XIIth Dynasty, and is now one of the most fertile areas of Egypt. The Mediterranean sardine fisheries in Egypt never exceeded 30,000 tons a year. Now, after a temporary absence, some sardine is coming back to the coastal waters of the Nile Delta. The fisheries resources of Lake Nasser have scarcely begun to be tapped. The catch in 1971 was 5,000 tons and, in 1972, 7,500 t o n s - mostly of the popular and cheap Tilapia. The fishing so far is mainly done by the local individual fishermen, and commercial fishing has not yet been developed to its full capacity. A fisheries research unit at Aswan is trying to assess the maximum size o f the permissible commercial catch for sustained yields. This catch will, hopefully, more than compensate for the Mediterranean sardine which may still be available. As to the capacity of the High Dam to support the population of Egypt, it seems enough to state that practically the entire young population of Egypt is able to live without lowering the standard of living of its elders. Between 1956 and 1972 the population increased from 23 millions to 36 millions; thus some 13 million people were added, all naturally less than 16 years old. Without the High Dam and its operative increasing of agricultural productivity, this addition to the population would surely have lowered the available food per person quite drastically. What other project except the High Dam could have provided young Egyptians with the vital necessities of survival without breaking the backs of their parents? Birth control is a very slow method to stabilize populations in agrarian societies. It is actively publicized in Egypt but will surely not be decisive within the near future. Egyptian ecologists therefore wish to see verdicts on the Aswan High Dam based on a balanced outlook. Every dam has its negative sides; those of the High Dam are not necessarily more important or more serious than the others'. Let us stop this wasteful trend of exaggeration and over-simplification which only jeopardizes the future role that enlightened ecological practice is bound to play in the development
CLEANING OF OIL-COVERED BIRDS
The findings and feelings of other workers that water repellency of feathers is due to feather structure and not to natural oils has been substantiated by our research. The technique which we use is with a solvent that effectively removes all contaminating oils, as well as the natural feather oils, but this we have found need cause no harm. The major criteria of cleaning an oiled bird for a quick release back to the wild depends upon (1) complete and thorough cleaning off of the contaminating oil, (2) leaving no residue of the cleaning agent on the feathers, and (3) being sure that the feathers are disturbed as little as possible. Complete removal of soaps, detergents, or other such cleaning agents as may be used in an aqueous cleaning procedure, is extremely difficult, if not well nigh impossible. Because complete cleaning is so important, we use a hydrocarbon solvent called Shell Sol 70 that is effective, efficient, safe, and completely removable from the feathers by evaporation. Its constitution by percentage of volume is: paraffins 98.9, aromatics 0.4, and olefins 0.7. The procedure is as follows. A series of five numbered dish-pans (12 x 14 x 5 in = 30.5 x 35.6 x 12.7 cm) are placed in sequence on a work-table (Fig. 1). Pans Nos. 1, 2, 4, and 5, are each about three-quarters filled with two gallons (7.57 litres) each of the solvent Shell Sol 70. Pan No. 3 is left empty to be used as a rinse-pan. A five-gallon (18.9-1itre) reservoir containing the solvent is placed on a shelf or platform stand about two to three feet (61 to 91 cm) above the shoulders of the workers. An eight- to ten-foot (2.4 to 3 m) length of Neoprene tubing (1 in = 6.35 mm inside diameter) is attached to the overhead solvent reservoir which leads down to the work-table. Under cold climatic conditions, the solvent from the reservoir is heated by passing it through a
291
has been readily forthcoming. Its activities have been schemes in Africa. The Sennar Dam, which was carried out on an essentially personal basis, and the inaugurated in 1925 to irrigate the large Gezira Scheme apellation 'The CIPO family' is a realistic description. for cotton production, resulted in the spread of bilharziasis among Sudanese peasants in the Gezira. PHYLLIS BARCLAY-SMITH, The Roseires (Fig. 1), Kariba, and Volta, Dams were Secretary-General, International Council for Bird Preservation, c/o British Museum (Natural History), Cromwell Road, London S W 7 , England
IN FAVOUR OF THE ASWAN HIGH DAM
With the growth of ecological literature in the past decade, the Aswan High Dam of Egypt is becoming, in the writings of a number of ecologists, something of a 'classical' textbook example of an ecological misdeed. In textbooks, popular accounts, proceedings of conferences, etc., one finds the High Dam commonly mentioned in this context. Except for a few eminent ecologists, who perceive the merits of the High Dam for what they are, many authors are apt to overlook the positive side of this large-scale project. The origins of this largely negative attitude cannot be disentangled from the international situation which beset the financing and construction of the High D a m - - a situation that is too well known to need recounting here. Several of the newspapers which stressed the negative sides of the project at that time did not appear to have considered the real welfare of the Egyptian people. Yet it should not be forgotten that these negative sides are not peculiar to the High Dam; hundreds of dams are built throughout the world, but it seems to be mainly the Aswan High Dam that is expressly chosen for horror-stories. When ecology and conservation became subjects to be written about profusely for the scientific community and the general public, some ecologists were led to believe that the widespread press material about the High Dam could be taken as a ready example of an ecological disaster. For 'disaster' is the description actually used in more than one respectable text on ecology. Let us consider soberly the principal negative effects of the Aswan High Dam which are recurrently mentioned. They boil down to the spread of bilharziasis, silting, and the depletion of the Mediterranean sardine fisheries. In addition, it is alleged that the Dam will not help to increase food production enough to feed the number of people who were added to the population during the Dam's construction period. We will now deal with each of these objections in turn. The spread of bilharziasis follows all large irrigation
Fig. 1.
The Roseires Dam which is holding back almost half of the silt carried by the Blue Nile.
built more or less contemporaneously with the Aswan High Dam, yet the health hazards associated with them are given brief mention--sometimes in connection with the High Dam just in order to emphasize the latter's presumed hazards. Already before the Dam was built, up to 90 per cent of the rural population in some areas of Egypt suffered from bilharziasis. The Ministry of Health took immediate measures to control the disease in the Aswan, Qena, and Sohag, Governorates downstream from the Dam when the incidence of the disease was noted to rise. These measures include the establishment of rural health service units to serve every village having a population of more than 5,000. Piped water is now within reach of 85 per cent of the population of Egypt. The new irrigation canals are dug in straight lines, are lined with limestone blocks, and have their aquatic weeds dredged out to deprive snails of suitable breedinggrounds. Actually, the control of bilharziasis is a complicated problem associated with several factors, among which are the standard of living of the peasant, his social and cultural make-up, and his clinging to some unhygienic habits which are encouraged by the prevalent methods of irrigation. Whatever the means by which bilharziasis is to be eventually controlled, the High Dam and Egypt's growing population could not possibly wait for this control to materialize. The problem of silting in Lake Nasser--which has developed by flooding the reaches of Lower Nubia-can, from the following data, be easily understood to be much exaggerated. The present yearly amount of silt in the Blue Nile passing at Khartoum after the
292
Biological Conservation
construction of the Roseires Dam is 55 million tons. of Egypt and indeed of the world. Let us, instead, If the specific gravity of silt is taken as 1.5, the total discuss more fruitfully the means to nullify the negative volume of this silt would be 37 million m 3. As the effects of all projects destined for human welfare and storage capacity of Lake Nasser is 130 thousand let us maintain balanced approaches that will convince million m 3, the time it would take to silt up only policy-makers and the general public that wise one-fifth of its volume would be seven hundred years. environmental considerations are associated with Almost all the silt is now laid down at the southern long-term benefits. This is the message of ecological end of the Lake. In future, this deposited silt could sciences. ultimately be dredged and spread over arable l a n d - SAMIR I. GHABBOUR, with great benefit to crops, if a feasible method could Department of Natural Resources, be developed for this. Alternatively, it could add Institute of African Research and Studies, valuable new land for agriculture, thus repeating University of Cairo, the story of the Fayoum depression which was used 33 Misaha Street, Dokki, Giza, Egypt. as a reservoir, presumably in the XIIth Dynasty, and is now one of the most fertile areas of Egypt. The Mediterranean sardine fisheries in Egypt never exceeded 30,000 tons a year. Now, after a temporary absence, some sardine is coming back to the coastal waters of the Nile Delta. The fisheries resources of Lake Nasser have scarcely begun to be tapped. The catch in 1971 was 5,000 tons and, in 1972, 7,500 t o n s - mostly of the popular and cheap Tilapia. The fishing so far is mainly done by the local individual fishermen, and commercial fishing has not yet been developed to its full capacity. A fisheries research unit at Aswan is trying to assess the maximum size o f the permissible commercial catch for sustained yields. This catch will, hopefully, more than compensate for the Mediterranean sardine which may still be available. As to the capacity of the High Dam to support the population of Egypt, it seems enough to state that practically the entire young population of Egypt is able to live without lowering the standard of living of its elders. Between 1956 and 1972 the population increased from 23 millions to 36 millions; thus some 13 million people were added, all naturally less than 16 years old. Without the High Dam and its operative increasing of agricultural productivity, this addition to the population would surely have lowered the available food per person quite drastically. What other project except the High Dam could have provided young Egyptians with the vital necessities of survival without breaking the backs of their parents? Birth control is a very slow method to stabilize populations in agrarian societies. It is actively publicized in Egypt but will surely not be decisive within the near future. Egyptian ecologists therefore wish to see verdicts on the Aswan High Dam based on a balanced outlook. Every dam has its negative sides; those of the High Dam are not necessarily more important or more serious than the others'. Let us stop this wasteful trend of exaggeration and over-simplification which only jeopardizes the future role that enlightened ecological practice is bound to play in the development
CLEANING OF OIL-COVERED BIRDS
The findings and feelings of other workers that water repellency of feathers is due to feather structure and not to natural oils has been substantiated by our research. The technique which we use is with a solvent that effectively removes all contaminating oils, as well as the natural feather oils, but this we have found need cause no harm. The major criteria of cleaning an oiled bird for a quick release back to the wild depends upon (1) complete and thorough cleaning off of the contaminating oil, (2) leaving no residue of the cleaning agent on the feathers, and (3) being sure that the feathers are disturbed as little as possible. Complete removal of soaps, detergents, or other such cleaning agents as may be used in an aqueous cleaning procedure, is extremely difficult, if not well nigh impossible. Because complete cleaning is so important, we use a hydrocarbon solvent called Shell Sol 70 that is effective, efficient, safe, and completely removable from the feathers by evaporation. Its constitution by percentage of volume is: paraffins 98.9, aromatics 0.4, and olefins 0.7. The procedure is as follows. A series of five numbered dish-pans (12 x 14 x 5 in = 30.5 x 35.6 x 12.7 cm) are placed in sequence on a work-table (Fig. 1). Pans Nos. 1, 2, 4, and 5, are each about three-quarters filled with two gallons (7.57 litres) each of the solvent Shell Sol 70. Pan No. 3 is left empty to be used as a rinse-pan. A five-gallon (18.9-1itre) reservoir containing the solvent is placed on a shelf or platform stand about two to three feet (61 to 91 cm) above the shoulders of the workers. An eight- to ten-foot (2.4 to 3 m) length of Neoprene tubing (1 in = 6.35 mm inside diameter) is attached to the overhead solvent reservoir which leads down to the work-table. Under cold climatic conditions, the solvent from the reservoir is heated by passing it through a