The general plan of the scheme is shown by Fig. 14 and Fig. 2, Plate XVIII. The roof, which has an area of 1 hectare, has been laid out with walks and grass plots, and the surrounding embankments have been converted into driveways. Above the reservoir a small plazuela of 1/2 hectare has been laid out with a space above it for a band-stand. The whole of the ground has been encircled with carriage drives, on which it is the intention to plant shade trees. The lay-out of this land also embraced the scheme for protecting the reservoir by draining the surface-water away to the irrigation ditches. COMPARISON OF SOUTH AND OBISPADO RESERVOIRS. The two reservoirs are practically of the same capacity, the only difference being the level of the overflows in their relationship to the roof, which gives the Obispado Reservoir a slightly greater capacity. Some comparative figures may be of interest, owing to the differences in type and construction. Table 7 gives the comparative quantities of material in each reservoir proper, that is to say, exclusive of the valve-houses, lay-out of grounds, etc. TABLE 7.--COMPARISON OF MATERIALS IN SOUTH AND OBISPADO RESERVOIRS. ==========================+===============================+============ | SOUTH RESERVOIR. | _OBISPADO RESERVOIR._ +--------+-------------+--------+------------ | | Quantities, | | Quantities, | No. | in cubic | No. | in cubic | | meters. | | meters. --------------------------+--------+-------------+--------+------------ _Earthwork:_ | | | | Total excavation | ... | 34,000 | ... | 56,479 Placed in embankment | ... | 31,500 | ... | 7,255 Placed in spoil banks | ... | 2,500 | ... | 49,224 +--------+-------------+--------+------------ _Concrete:_ | | | | Columns (including | | | | foundations) | 135 | 1,240 | 356 | 543 Primary beams | 135 | 440 | 374 | 462 Secondary beams | 670 | 515 | 1,252 | 576 Side-walls | ... | 1,255 | ... | 710 | | | | | Square | | Square | | meters.| | meters.| Roof slab | 5,140 | 520 | 10,206 | 1,020 Floor | 4,070 | 780 | 9,200 | 2,120 Parapet walls | ... | 90 | ... | 165 +--------+-------------+--------+------------ Total concrete | ... | 4,840 | ...