The average gestation period for rabbits is 31 days; however, it can vary from 29 to 35 days. Does should be pregnancy-checked 14 days after mating. If not pregnant, they can be re-bred immediately.
Buttresses and an arch of the Roselend Dam in France. A buttress dam or hollow dam is a dam with a solid, water-tight upstream side that is supported at intervals on the downstream side by a series of buttresses or supports.The dam wall may be straight or curved. Most buttress dams are made of reinforced concrete and are heavy, pushing the dam into the ground.ater pushes against the dam, but the buttresses are inflexible and prevent the dam from falling over. Buttress or hollow gravity dams were originally built to retain water for irrigation or mining in areas of scarce or expensive resources but cheap labour.
The one advantage of a gravity dam is its rather simple design, with most dams being a straight vertical wall across a valley or gorge way. However, gravity dams can also be designed curved, as in the Hoover dam. Gravity dams are very durable and still highly preferred over buttress dams and arch dams.The one drawback is that gravity dams require a large amount of material and construction to build are therefore relatively expensive.he one advantage of a gravity dam is its rather simple design, with most dams being a straight vertical wall across a valley or gorge way. However, gravity dams can also be designed curved, as in the Hoover dam. Gravity dams are very durable and still highly preferred over buttress dams and arch dams.