| Sepidrud | |
| Name Other: | Sefidrud |
| Map: | Sefidrivermap.png |
| Subdivision Type1: | Country |
| Subdivision Name1: | Iran |
| Subdivision Type2: | Provinces |
| Subdivision Name2: | Gilan |
| Subdivision Type5: | City |
| Subdivision Name5: | Rasht |
| Length: | 670km (420miles) |
| Source1 Location: | Alborz Mountains |
| Mouth: | Caspian Sea |
| Tributaries Left: | Qizil Owzan |
| Tributaries Right: | Shahrood |
The Sepid-Rud (Persian: سفیدرود|lit=white river, سپیده رود) (also known as Sefid-Rud) is a river, approximately 670km (420miles) long, rising in the Alborz mountain range of northwestern Iran and flowing generally northeast to empty into the Caspian Sea at Rasht.
Other names and transcriptions include Sepīd-Rūd, Sefidrud, Sefidrood, Sepidrood, and Sepidrud. Above Manjil, "Long Red River".[1] [2]
William Smith equated the river with the Amardus (Greek, Ancient (to 1453);: Ἀμάρδος) or Mardus (Μάρδος) river of antiquity.[3] [4]
The river is historically famous for its abundant fish, especially the Caspian trout, Salmo trutta caspius.[5]
The Sefid-Rud has cut a water gap through the Alborz mountain range, the Manjil gap,[6] capturing its two headwater tributaries, the Qizil Üzan and Shahrood rivers. It then widens the valley between the Talesh Hills and the main Alborz range. The gap provides a major route between Tehran and Gīlān Province with its Caspian lowlands.[6]
In the wide valley before the Sefid-Rud enters the Caspian Sea, a number of transportation and irrigation canals have been cut; the two biggest are the Khomam and the Now.[7]
The Sefid-Rud was dammed in 1962 by the Shahbanu Farah Dam (later renamed Manjil Dam),[8] which created a reservoir and allowed the irrigation of an additional 23800NaN0.[8] The reservoir mediates some flooding and significantly increased rice production in the Sefid Rud delta.[9] [10] The hydroelectric component of the dam generates 87,000 kilowatts.[8] The completion of the dam had a negative impact on the river's fisheries, through reduced stream flow (due to diversion), increased water temperature, and decreased food availability, especially for sturgeon but also for the Caspian trout.[11]
The river was known in antiquity as Mardos (Greek, Modern (1453-);: Μαρδος; Latin: Mardus) and Amardos (Greek, Modern (1453-);: Αμαρδος; Latin: Amardus).[2] In the Hellenistic period, the north side of the Sefid (then Mardus) was occupied by the Cadusii mountain tribe .[12]
David Rohl proposes identification of Sefid-Rud with the Biblical Pishon river.