The Outflow Is Set by Law
Soviet planners treated Lake Sevan as an inefficiency — water evaporating off a shallow surface instead of turning turbines — and took roughly nineteen metres off it. Armenia has spent the sixty years since digging tunnels to put the water back, and now fixes the lake's annual outflow by an act of parliament.
Sevanavank was built on an island. The monastery was founded in 874 on a rock in the middle of Lake Sevan, which is the whole point of a monastery on a rock, and monks were rowed out to it for a thousand years. You now drive to it. A causeway of dry ground runs from the shore to a hill with two churches on it, and the old waterline is legible on the slope as a change in the vegetation, well above where the water is today.
Armenia has been trying to undo that for sixty years, and the mechanism it uses is unusual enough to be worth stating plainly: the amount of water allowed to leave Lake Sevan in a given year is set by law, voted on in the National Assembly. Not by a utility, not by a ministry with discretion, not by a water tariff. By a bill.
A lake as an inefficiency
The argument that drained it was made before the Soviet Union existed. In 1910 an engineer named Sukias Manasserian published a pamphlet whose title translates roughly as the evaporating billions — the claim being that a large, shallow, high-altitude lake was losing enormous volumes of water to the air for no return, and that the rational thing was to run most of it downhill through turbines and onto farmland instead. Sevan sits at about 1,900 m (6,230 ft), it was then around 1,400 square kilometres, and much of that area was a shallow shelf. On paper the case was strong. Soviet planning took it up in the 1930s and built the Sevan–Hrazdan cascade: a chain of hydroelectric stations down the Hrazdan river, fed by the lake, with irrigation for the Ararat plain drawn off the same flow. The ambition at its fullest was to lower the water by tens of metres and leave only the deep northern basin. That never quite happened, but by the early 1970s the level had fallen about nineteen metres and the lake had lost well over a third of its volume.
What the drop cost
Shallowing a lake concentrates everything in it. Nutrients that had been diluted across a much larger volume were not, water temperatures rose, and Sevan shifted from a clear oligotrophic lake to something considerably less stable. The endemic Sevan trout, ishkhan, exists in four subspecies and two of them are considered extinct. Whitefish, introduced from Russian lakes in the 1920s and 1930s to replace a fishery that was already failing, became the commercial catch instead — and then collapsed in turn in the 2000s, to the point that commercial fishing has been restricted and repeatedly banned outright.
The island became a peninsula, which is the version everyone photographs. The fishery became a subsidy question, which is the version that mattered.
Two tunnels, the other way
The reversal is a piece of engineering nobody visits and it is the most impressive thing in the watershed. Work began in 1963 on a tunnel to bring the Arpa river, which drains south into Vayots Dzor, north under the mountains into Sevan instead. It is 48.3 km (30 mi) long, it took eighteen years, and water first came through in 1981. A second tunnel, 21.6 km (13.4 mi), was driven from the Vorotan river to join it and opened in 2004. Between them they add a river's worth of inflow to a lake that had been engineered to have one outflow too many. Then the 1990s undid a good deal of it: with the borders shut, the gas pipeline through Georgia repeatedly cut and the Metsamor nuclear plant closed after the 1988 earthquake, Armenia had almost no way to make electricity except the Hrazdan cascade, and it drew the lake for power all over again. That is the part that makes the eventual law comprehensible. The drawdown was not stupidity. It was a state with no other options doing the only thing available, twice, sixty years apart.
The law
The Law on Lake Sevan was passed in 2001. It set a target of raising the water by six metres over roughly three decades, capped the ordinary annual withdrawal for irrigation at 170 million cubic metres, and — the operative part — required that the year's actual permitted release be approved by parliament as part of an annual programme. In a dry summer the government goes to the National Assembly and asks for more, and the debate is public, on the record, and about a number. The level has come back up by close to four metres since the law was passed, which is behind schedule and is still a lake rising rather than falling.
What the rising water found
Three decades of low water had been treated as the permanent shoreline. Roads, holiday cabins, restaurants and whole stretches of beach infrastructure were built on ground that was lakebed, and the rise has been drowning them one contour at a time. Worse, vegetation had colonised the exposed bed — scrub, and in places planted trees — and drowned vegetation rots. That decomposition, plus sewage from lakeside towns whose treatment plants were never adequate for their summer population, plus warmer water, produced the thing Sevan is now known for: since 2018 the lake has bloomed cyanobacteria in late summer and turned visibly green.
Which leaves a genuine trade-off rather than a villain. Water kept in Sevan is water not on the Ararat plain, and the plain has its own crisis — the artesian basin under it has been drawn down hard since the 2000s, largely by fish farms pumping cold groundwater, so the pressure to release more from the lake is partly a bill for over-pumping somewhere else. The visitor sees none of this. What you see from the hill at Sevanavank is a very large blue lake with a treeline on the far shore, and, if you look down rather than out, a band of drowned scrub in the shallows and a jetty that was built for a different water level. Both of those are the policy, working.