6802
By the early 18th century , river navigations such as the Aire and Calder Navigation were becoming quite sophisticated , with pound locks and longer and longer " cuts " ( some with intermediate locks ) to avoid circuitous or difficult stretches of river .
 Aire and Calder Navigation
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Aire and Calder Navigation