AQUA IULIA
* an aqueduct constructed by Agrippa in 33 B.C. and repaired by Augustus in 11-4 B.C. (Frontinus, de aquis i. 4, 9, 18, 19; ii. 68, 69, 76, 83, 125; Not. app. ; Pol. Silv. 545, 546).The springs of the aqua Iulia are situated about half a mile above the abbey of Grottaferrata. Frontinus says that they were 2 miles to the right of the twelfth mile of the via Latina, but this is too far. The length is given as 15,4261 paces. The supply was 1206 quinariae, or 50,043 cubic metres in 24 hours. (162 quinariae more were received from the Claudia; and 190 given to the Tepula.) Several cippi are known, all of the time of Augustus.
No. 302 has been found near the springs and 281 not far below the abbey; while others (157, 156, 154, 153) have come to light at Capannelle near the seventh mile of the via Latina, before the channel begins to run above ground upon the arches of the Marcia (CIL vi. 31563 b=xiv. 4278; NS 1887, 73, 82, 558, 559; 1914, 68; 1925, 51; BC 1886, 313; 1887, 131).
The whole of this group belongs to the restoration of 11-4 B.C. But another cippus has been found, also above the abbey, bearing the number 2. It dates from 14 A.D., and must belong to another restoration by Augustus, of which we have no other record (NS 1893, 240; CIL vi. 31563 c; EE ix 970).
From the point of its emergence the aqua Iulia runs, above the aqua Tepula, upon the arches of the AQUA MARCIA (q.v.), and the main channel goes to its terminal castellum. But a branch ran to the NYMPHAEUM ALEXANDRI (q.v.) of which some arches still remain in the Piazza Guglielmo Pepe (called Forma Claudiana in Eins. 5. 3; 6. 2; cf. Mon. L. i. 479; DAP 2. ix. 403).
Frontinus tells us that before the construction of the aqua Claudia, the Marcia and Iulia supplied the Caelian and the Aventine (ii. 76, 87); in his own time a part of the Marcia was diverted at Spes Vetus and delivered to the reservoirs of the former hill. See Jord. i. I. 466; LA 295-310 ; LR 51-53; BC 1885, 131; 1917, 235; DAP 2. vii. 237; PBS v. 232, 386-388.
The water from the springs of the aqua Iulia (not the aqua Crabra: Frontinus, i. 9) is now brought into Rome by the channel called the Marrana Mariana (constructed by Calixtus II in 1122), but was always used mainly for mills and for irrigation (LPD ii. 379; LA 325-327).