Turkmenistan: The Bradt Travel Guide, Paul Brummell, Bradt Travel Guides, 2006, ISBN 978-1-84162-144-9, ... The state of maintenance of the Kara Kum Canal is a cause for concern, and water efficiency is poor. heavy off-take from the Amu Darya has been one of the contributory factors in the gradual drying up of the Aral Sea ...