score:11
Note item (6) - New Harbour Entrance on your map. This entrance was constructed in 147 B.C. (the third year of the siege) simultaneous with item (7) - Scipio's Mole blocking the original entrance. During the siege the Carthaginians were able to continue trading overseas, albeit with limited success because of Rome's influence.
The Siege was prosecuted incompetently for the first two years. Only with the election as Consul of Scipio Aemilianus for 147 B.C. were the Romans finally successful in prosecuting the siege. Scipio arranged to construct the eponymous Mole and finally restored morale to the Roman troops enabling them to breach the walls and begin the house-to-house elimination of the garrison and conquest of the city.
Also, as shown here modern Tunis averages 45 cm of rainfall annually, and is very near the site of Carthage. This is roughly what both Aruba and Bonaire receive annually and seems adequate to refresh cisterns for quite some time if provision exists for capturing it as is done on those two islands.