The Thracian word alta
Word alta
Meaning current, stream
See also Thracian: ala ‘current, stream’

Other words that might be of interest
achel- ‘water’, arma ‘swamp’, ars ‘to flow’, arta(s) ‘river’, e(i)b ‘to flow’, iuras ‘water, river’, kaba(s) ‘bog, swamp’, kalsas ‘dry, dried up’, mar ‘water, river, bog’, ostas ‘river mouth’, pala ‘swamp’, sara ‘river’, sind(u)- ‘river’, strumon ‘river’, opa ‘water’, krisos ‘river name’