...according to Wikipedia

The Jordan River (American English) or River Jordan (British English) is 156 mile long river in West Asia flowing to the Dead Sea. Currently, the river serves as the eastern border of the State of Israel and of the Occupied Palestinian Territories. In Christian tradition, Jesus was baptised in it by John the Baptist. The Hashemite Kingdom of Jordan takes its name from this river.

Its section north of the Sea of Galilee (meaning Lake of Tiberias) is within the boundaries of Israel, and forms the western boundary of the Golan Heights. South of the lake, it forms the border between the Kingdom of Jordan (to the east) and Israel and the West Bank (to the west).

THE BIBLE
The New Testament states that John the Baptist baptised unto repentance[8] in the Jordan (Matthew 3:5-6; Mark1:5; Luke 3:3; John1:28). This is recounted as having taken place at Bethabara (John 1:28).
Jesus came to be baptised by him there (Matthew 3:13; Mark 1:9; Luke 3:21, 4:1). The Jordan is also where John the Baptist bore record of Jesus as the Son of God and Lamb of God (John 1:29-36).
The prophesy of Isaiah regarding the Messiah which names the Jordan (Isaiah 9:1-2) is recounted in Matthew 4:15.
The New Testament speaks several times about Jesus crossing the Jordan during his ministry (Matthew 19:1; Mark 10:1), and of believers crossing the Jordan to come hear him preach and to be healed of their diseases (Matthew 4:25; Mark 3:7-8). When his enemies sought to capture him, Jesus took refuge at Jordan in the place John had first baptised (John 10:39-40).

Human impact
In 1964, Israel began operating a dam that diverts water from the Sea of Galilee, a major Jordan River water provider, to the National Water Carrier. Also in 1964, Jordan constructed a channel that diverted water from the Yarmouk River, another main tributary of the Jordan River. Syria has also built reservoirs that catch the Yarmouk's waters. Environmentalists blame Israel, Jordan and Syria for extensive damage to the Jordan River ecosystem.
In modern times, the waters are 70% to 90% used for human purposes and the flow is much reduced. Because of this and the high evaporation rate of the Dead Sea, the sea is shrinking. All the shallow waters of the southern end of the sea have been drained in modern times and are now salt flats.
Small sections of the Jordan's upper portion, near the Sea of Galilee, have been kept pristine for baptisms. Most polluted is the 60-mile downstream stretch - a meandering stream from the Sea of Galilee to the Dead Sea. Environmentalists say the practice has almost destroyed the river's ecosystem. Rescuing the river could take decades, according to environmentalists. In 2007, Friends of the Earth Middle East (FoEME) named the Jordan River as one of the world's 100 most endangered ecological sites, due in part to lack of cooperation between Israel and neighboring Arab states.[3] The same environmentalist organization said in a report that the Jordan River could dry up by 2011 unless the decay is stopped. The flow rate of the Jordan River once was 1.3 billion cubic metres per year; as of 2010, just 20 to 30 million cubic metres per year flow into the Dead Sea. For comparison, the total amount of desalinated water produced by Israel by 2012 will be about 500 million cubic metres per year.