Water. Acts on Aggregate. has_property ../conservation/water_quality. has_property Water_flow. has_type Acid_water. has_type Brackish_water. has_type Flowing_water. has_type Fresh_water. has_type Frozen_water. has_type Ground_water. has_type No_water. has_type Sea. has_type Still_water. has_type Surface_water. Hydrology ontology ../content/ontology_hydrology.htm Hydrology ontology no links ../content/ontology_hydrology_txt.htm is_part_of Geography. Quality http://www.google.com/Top/Science/Environment/Water_Resources/Water_Quality/ Treatment http://www.google.com/Top/Society/Issues/Health/Water_Treatment/ US office of water http://www.epa.gov/water/ Water quality indicators       Vr.155, Dec 2010     Readme      ..