Abstract: A water flooding composition in a method of secondary hydrocarbon recovery. The water flooding composition includes water and a thickening polymer. The thickening polymer includes a hydroxyethyl cellulose backbone polymer having a molecular weight of between about 1,000,000 and about 2,000,000 and a hydrophobic modifier. The hydrophobic modifier has a substitution level in the thickening polymer of between about 0.1 percent and about 2 percent by weight of the thickening polymer. The hydrophobic modifier is an alkyl hydrocarbon based material containing between about 10 and about 24 unsubstituted carbon atoms per group. The thickening polymer has a concentration in the water flooding composition of between about 0.01 percent and about 1 percent by weight of the water flooding composition. The water flooding composition is formulated within these ranges so that the water flooding composition has a suitable viscosity/mobility and so that the water flooding composition is injectable.