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       Chapter II: A Concept for the National Capital

The Site

THE SITE

The site for the new Capital in Dodoma was selected from a study area of 6475 km2 (2500 square miles), centred on the existing town of Dodoma. The site selection process is described in detail in Appendix B to this report.

The study area includes what is now defined as the Capital City District (Urban). Of this, only a small part has been identified as the area which is most suitable for urbanization. The following site description includes the whole Capital City District (Urban), as well as the area of future urbanization within that district. A complete analysis of the Study Area is contained in Technical Supplement No. 2, Natural Resources.

The Dodoma region is characterized by broad upland plains which are part of East Africa's central plateau. The plains shelve gently down to mbuga swamps and are separated by ranges of hills and punctuated by inselbergs, prominent, isolated rock outcrops. In their natural state, the plains are marked by open grassland with little or no tree or bush cover. Due to the erratic nature of the rains and the strong radiant heat of the sun, much of the grass is sparse, except in the low iying areas. Most common, however, are wooded grassland and bushland with thickets. These types of ground cover represent the majority in the Dodoma area. In many areas they are typified by groups of enormous baobab trees. The bush tends to be leafless and drab in the dry season, but springs to luxuriant life during the rains when the whole countryside turns a brilliant green. Woodlands form the remainder of the area, with the heaviest concentrations on the hills of the region.

The soils of the plains are generally sand-clay mixes, in which the sluggish drainage of the flat areas build up sediments of the finer clays or silts, as "black cotton" soil which is extremely poor for construction, but has good agricultural potential. The rocks are precambrian granitic forms which break through the plain to create the massive and spectacular silhouettes of the Dodoma and Hombolo Hills and the inselbergs, such as Mlimwa and Itega.

The plains are marked by numerous large swamps in the low lying areas, such as at Bahi and Nzinge. Where the catchment area is sufficient and the topography suitable, both natural and artificial lakes are found. Hombolo Lake is the largest of these, but smaller reservoirs have been formed by the Biringi, Mkalama and Matumbulu dams. A low lying catchment area, the Makutapora Basin just to the north of the existing town, acts as a water recharge area for the major source of water for the existing town of Dodoma.

In the site selection process for the identification of the areas suitable for urbanization and for the location of the Capital itself, care was taken to avoid the water recharge areas, the land with good agricultural potential and the hills. Areas with good soils for construction were chosen. These are generally found on the pediment slopes of the hills and are frequently characterized by good drainage, being in the range of 4% slopes without severe erosion problems.

plate5 The existing town of Dodoma is the site which was finally chosen for the Capital. Its visual features are, firstly, the expansive, virtually uninterrupted horizontal elements; from Dodoma, an enormous plain of this nature stretches far to the northwest; the dim distances of this plain can be seen from the pediment slopes of the site. Other plains occur to the west and south, but these are isolated from the site by the massif of the Dodoma Hills.

The Dodoma Hills rise about 400 metres above the general level of the plains. They are of great charm, with gentle valleys dividing them, such as the Ntyuka and the Luaha Valleys. Bounding the northerly plain to the north-east are the more mountainous Hombolo Hills, rising 900 metres above the plain. From the site of the Capital these appear as a massive wall, which encompasses the plain, fascinating in their changing moods and colours.

plate6 Within the boundaries of the Hombolo and the Dodoma Hills, the Dodoma Plain is far from featureless. Perhaps the strongest element is the long but gentle Hombolo Ridge, 100 metres high running in a north-east south-west direction and connecting the two major massifs. This ridge of land, which marks the boundary between the Hombolo and Ihumwa watershed areas, defines the Dodoma plain on the east and tends to emphasize the enclosure or encirclement of the town. The openness of the plain stretches to the north-west, the direction of the Rift Valley, Olduvai and the rest of Africa. The Hombolo Ridge is not sufficiently high, however, to present a strong barrier, but is rather a modulation of the plain which breaks its infinite scale, brings enclosure to Dodoma and separates it subtly from the Luaha Valley which opens to the vast plains stretching to the east. At the north end of Hombolo Ridge lies Lake Hombolo, a long narrow body of water which parallels the ridge. The southern termination of the Ridge is Chimwaga, the most dominant hill of the Dodoma group. At the junction of the ridge and Chimwaga is a commanding site from which there are views of 50 to 60 kilometres over the plains to almost all points of the compass. The great spaces of the east and the west meet at this point — a hinge between the two major areas of future Capital development. Below it, encircled by the hills and ridge, is the existing town of Dodoma. To the west, the horizon is defined by a series of scattered rock outcrops, before the land drops gently to the Bahi depression and the Bahi swamp.

Plate 6 shows the central area of the site. On this plan is shown the location of the junction of the Hombolo Ridge with the Dodoma Hills at Chimwaga. To the west of Chimwaga, and separated from it by the Ntyuka Valley, sits the mass of Imagi, a hill of distinctive silhouette with massive rock faces, part of the Dodoma chain.

Behind it, to the south, the Dodoma hills form a gentle barrier. On the lower slopes of Imagi are the southern boundaries of the existing town. A short distance to the west of the town lies Itega, a major inselberg, which terminates the enfolding sweep of the land which comes from Hombolo, via the ridge, through Chimwaga, then Imagi, to the massive blocks of rock on Itega. Within the sweeping edges to this bowl lies Dodoma, pinpointed by the isolated, but spectacular, form of the inselberg Mlimwa.

The Dodoma site in this clearly defined bowl, suggests a master plan of urban communities which form a series of gently curving loops following the valleys and hill ridges. To the east, beyond Chimwaga, the land in the Luaha River valley presents the opportunity for a more linear form of urban extension, echoing the line of the eastern extension of the Dodoma Hills.



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Copyright: Project Planning Associates Limited, Toronto, Canada, directed by Mr. Macklin Hancock and recipient "The Government of Tanzania, Capital Development Authority under the auspices of Mr. George Kahama.".