Map symbols for river and river related features on Latvian topographic maps of the 1920s and earlier. From the book
Apzimejumi Merniecibas un Kulturtechniskiem Planiem
(Legends from Surveying and Cultural-Technical Plans)
Ministry of Agriculture
Riga, Latvia, 1928.
Original plate with translation to English below:
from top to bottom:
Fjords: Small and for General Traffic
Wharf and Tow-path
Lake extension – divided
Waterfall
Lake
Rapids
Ditch
Surface and underwater rock
Canal
Whirlpool
Lighthouse
River overflow
Shallows
Flow direction
Ravines and Streams
Pool/Reservoir
Mill Dam
Underground water pipe
Making Maps: DIY Cartography 
[…] to represent things on my map. Professor Krygier, whom I am working with on this project, showed me river symbols used in maps in Latvia, in which they did not resemble the usual representation of the jagged, meandering thin blue lines […]