I once drove several hours to fish a reservoir that had looked perfectly healthy on the map.
The map was right in one sense. The reservoir was there. Most of the water had gone somewhere else.
The bank I remembered was now a long walk across stones and dried mud. A comfortable fishing spot had become an excellent place to inspect old bottles, lost tackle and bits of road that had not seen daylight for years.
These days I check the level before putting tackle in the car.
That does not tell me whether I will catch anything. It does tell me whether the water is likely to be where I left it.
Start with the Reservoir, Not the Region
News reports usually talk about Spain’s water reserves as a national percentage or divide the country into river basins. That is useful for understanding the general situation. It is less useful when you want to know what has happened at one particular reservoir.
Two lakes in the same part of Spain can behave very differently.
One may be used heavily for irrigation while another remains comparatively stable. Water may be released for supply, electricity generation or management farther down the river. Local rainfall does not always produce an immediate rise either.
I search for the reservoir by its Spanish name and check its individual figures. If you search only for “water levels in Extremadura” or “Spanish reservoirs full”, you can end up with a reassuring statistic that bears little resemblance to the bank you intend to fish.
Make sure you have the right reservoir. Spain has enough repeated and similar place names to make this less obvious than it sounds.
The Official Weekly Hydrological Bulletin
Spain’s Ministry for the Ecological Transition publishes a weekly hydrological bulletin covering mainland reservoirs with a capacity greater than five cubic hectometres.
It includes the capacity and stored volume of individual reservoirs. There is also a map-based viewer and historical data going back to 1988.
The percentage full is the number most people notice first. I also look at the actual volume and compare it with the previous week. A reservoir sitting at 55 per cent and falling steadily tells a different story from one sitting at the same percentage after a recent rise.
The historical comparison can be useful too. A figure that looks low may be fairly normal for that reservoir in August. Another lake at the same percentage could be far below its usual summer level.
The information is provisional and it is generally updated weekly. Treat it as a good starting point rather than a live picture of the exact waterline.
Check the River Basin Authority
Spain’s water system is divided between different river basin authorities, known as confederaciones hidrográficas.
For reservoirs around Orellana and much of Extremadura, I also check the Confederación Hidrográfica del Guadiana. It publishes information about reservoirs under its management, including weekly reports.
Elsewhere you may need the authority responsible for the Ebro, Tajo, Duero, Guadalquivir or another basin. Searching the reservoir name together with confederación hidrográfica usually points you in the right direction.
These sites are not always designed with a man checking water levels on his phone at five in the morning in mind. Some hide the useful information inside PDF reports or map viewers. Once you learn where a particular authority puts its figures, save the page.
A Percentage Does Not Show You the Bank
Knowing that a reservoir is 60 per cent full does not tell you whether your usual swim is accessible.
Reservoirs are not giant straight-sided baths. A relatively small change in stored volume can expose a wide area of shallow bank. On a steep section, a larger fall might move the edge by only a short distance.
Satellite imagery helps me understand the shape of the ground. Google Maps may show an older high-water image, so I do not use it as proof of current conditions. It can still reveal points, old tracks, stream beds and broad shallow areas likely to become exposed as the level falls.
I compare what I can see with the reservoir figures. If the latest image shows the lake at a known level, that gives me some idea of what a further rise or fall may mean on the ground.
It remains an estimate. A photograph taken by somebody who visited yesterday is worth more than a beautiful satellite image from three summers ago.
Local Reports Can Save a Wasted Journey
Tackle shops remain one of the best sources of current information.
You do not need to ask where the fish are being caught. Most anglers would sooner provide their bank details. Ask whether the water has dropped, whether a particular access track remains usable and whether any areas have been closed.
Local fishing groups can also help, although dates matter. Old photographs are frequently shared again without context. A picture of a full reservoir may have been taken in February or during a year when rainfall was completely different.
I look for several recent reports rather than relying on one dramatic post. “The reservoir is empty” can mean anything from a serious fall in level to somebody discovering that his favourite peg now requires a longer walk.
What Falling Water Reveals
A falling reservoir can make fishing harder, but it can also reveal useful information.
Old walls, roads, rocky shelves and the original river channel may become visible. I make a note of them and take photographs. Those features will disappear again when the water rises, but the fish may continue to use them.
It is also a chance to see where the hazards are. Tree stumps and sharp rocks explain some of the tackle lost during higher water. A smooth-looking area on a full reservoir can contain far more trouble than it appears to from the bank.
Exposed ground needs care. Mud near the edge can be deep even after days of hot weather. I do not drive onto a newly uncovered bank simply because somebody else has left tyre marks. They may have had a better vehicle or a worse understanding of consequences.
Checking Levels the Night Before
My final check is done the evening before travelling.
I confirm the latest stored volume, look for any notices from the relevant authority and check recent local reports. If access is uncertain, I choose a second area before leaving home.
This is particularly useful during summer reservoir fishing in Spain, when levels and usable banks can change quickly.
A full reservoir does not guarantee good fishing. A low one does not guarantee a blank. The figures simply stop me arriving with a barrow full of equipment at a bank now sitting half a kilometre from the water.
I have made that walk before. Once was enough.
