Are there hippopotamuses in the Jordan river?
No, hippos have ranged about as far north as Khartoum on the river Nile.
No. According to international law, no country "owns" a river. The right of navigation on a river is subject to the sovereignty of the river. A river that is entirely within the borders of one country is subject to that country's sovereignty. As the Jordan River forms the border between two states, neither can impose sovereignty over the river and, therefore, Israel and Jordan share administration of the Jordan River.
The Jordan River forms the border between Israel and Jordan. Therefore, half of the river is in each country wherever Israel borders Jordan to the north of the West Bank. (There is a small stretch of the Jordan which is wholly in Israeli territory as it leaves the Sea of Galilee and the Jordan River continues as the border between the West Bank and Jordan until the Dead Sea.)
The word "Jordan" means "the river that rushes down." And between Mount Hermon and the sea of Galilee that's exactly what it does! The Jordan River in Israel has no dam as there is not enough water that flows through it to turn enough turbines to make the enterprise worth doing. There is a dam on the Jordan River in British Columbia, Canada (which is an entirely different river). That dam is called the Jordan…