Sunday, May 19, 2024


When last I did any work on the hammers page of my wiki (which I abandoned to work on the Streetvendor's Guide), my next intended page would have been for "dam."  It's comforting to know that, after leaving off something for about 16 months, the work is still sitting right there, waiting to be done.  I don't have to think of what I ought to do, or want to do ... just what's next.

For a change, and because I need a post, let me produce the page here instead of on the wiki - so that it can be transcribed later.  We want to consider only dams that would be realistically created between the 15th and 17th centuries.  Dams were also made for canals, and canal work was prevalent at certain times in Chinese history, but not so much with the decline and collapse of the Ming dynasty, and certainly the practice wasn't widespread in Europe or anywhere else in the time period specified.  My game, I'll remind the reader, takes place in 1650; for this, I'm just going to pretend I have a game, just in case one pops up.

Dams are primarily constructed to provide a reliable source of water for irrigation, ensuring that crops can be watered during dry periods. Dams also supply a steady flow of water to power watermills. They ensure a consistent water supply for livestock and limited domestic uses, supplementing wells and natural water sources. Community cooperation is needed in maintaining these structures, with locals working together to manage water flow, remove sentiment and repair damage. Understanding of water contamination is minimal, given the time period, so the primary concern is maintaining the water level and the dam's integrity.

Construction involves simple techniques, using local materials such as earth, clay, stone and timber. Rare dams might be constructed with mortared stone. Typically, they're about 3 to 10 yards in height, with a generally modest length, most likely less than a hundred yards.  The reservoir would be quite small as well, most likely not larger than 20 or 30 acres.  A few acres is far more likely.  One benefit is that as water settles in a reservoir, sediment and particulates drift to the bottom, producing a clearer, cleaner water at the surface.  This isn't pure of course, as various contaminants and microorganisms would persist ... but to the late Renaissance mind, the water would taste better.  Modern concerns just aren't present, as the source of disease and other maladies is largely misunderstood.

In my infrastructure system, dams occur with type-5 hexes that have at least 2 hammers (H).  For these conditions to be met, the hex must have a significant river, not a little stream ... so there's plenty of water available with which to make a reservoir.  Such a dam facilitates the growth of population in the hex and supports the water needed to irrigate more land, so that type-5 hexes also have a notation of 3 food (3F) as well (type-6 only have 2F).  Type-5 hexes without a sufficient stream also produce 3F, without the 2 hammers, so we may assume that more irrigation is not the only reason for this.

It needs to be stated, though, that the extra food on the map stipulates not production, but surplus.  Meaning that a type-5 hex with 3F and 2H would probably support food than the same type hex with 3F and 1H.  Not that this is very important, and these numbers probably are confusing, but this can be pieced together by following links on the hammer's page, linked above.

Dam failures did occur, due to inadequate design, substandard materials, poor maintenance ... all the reasons they still fail now.  Of course, a thirty acre reservoir, when it breaks, isn't going to cause all that much damage.  Flooding might threaten a few, but the larger consequence would be crops lost, lands flooded, and the difficult task of rebuilding the dam.  There might be considerable fallout as persons left the area or as a few engineers were given the axe ... not in a nice way.

The Dutch began building dams to create "polders," low-lying tracts of land that could be farmed, in the 12th century, building on work done by earlier cultures, including the Egyptians and Romans, and in fact the Danes during the time of the Vikings, starting four centuries earlier.  Polders are a major infrastructure practice; as such, I'm adding it to type-3 hexes, needing 3 hammers.  Holland and Zeeland are extremely dense in population/infrastructure, so there would be a lot of such hexes.

 At the time of my game, before 1650, nothing like the impressive size we know today were attempted; large polders could encompass several hundred acres, but this is still less than a square mile (which have 640 acres each).  Small polders covered just a few acres, much like the size of reservoirs we discussed above.  So, keeping these things small in one's mind is a good practice.

Many reservoirs contain fish, having been drained from rivers, so there's little need to stock them, but fish were captured from nearby streams and then transported to reservoirs to be released.  This carrying was done in baskets, barrels and buckets, as available.  Often, there were designated places along the shoreline of larger reservoirs (and natural ponds as well) for the intended purpose of stocking, where the water was deep and the fish had ample space to disperse and acclimate.  Stocked fish are typically carp, trout, perch and whatever else might be native to the region.

I just had a vision of players rescuing some travellers with two wagons full of what looks like beer, but are in fact barrels full of water and baby perch.

Well, that's all I can think of.

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