Modifiers matching reservoir:

• liquid,
• seasonal,
• traditional,
• natural,
• vast,
• deep,
• environmental,
• home,
• large,
• impermeable,
• underground,
• local,
• geological,
• simple,
• subsurface,
• small,
• geologic,
• nonliving,
• fluid,
• mobile,
• internal,
• medical,
• external,
• geophysical,
• biological,
• sedimentary,
• stable,
• common,

Simple categories matching subsurface:

• facility,
• structure,
• variable,
• material,
• body,
• sorbent,
• item,
• defect,
• layer,
• liquid,
• property,
• condition,
• imperfection,
• feature,
• rock,
• formation,
• system,
• deposit,
• obstruction,
• separation,
• mineral,
• information,
• stratum,
• platform,
• process,
• measure,
• soil,
• fluid,
• attribute,
• data,
• void,
• artifact,
• drain,
• utility,
• area,
• construction,
• change,
• anomaly,
• excavation,
• object,
• detail,
• industry,
• component,
• cavity,
• variation,
• quantity,
• reservoir,
• installation,
• resource,