Webster’s Revised Unabridged Dictionary · 1913
Conservancy
Con·serv′an·cy (kŏn·sẽrv′an·sy̆), n. Conservation, as from injury, defilement, or irregular use.
[An act was] passed in 1866, for vesting in the Conservators of the River Thames the conservancy of the Thames and Isis. Mozley & W.