8.8.≈S8≈ Human-powered energy system - ( GWN - GTO ).

8.- Water Supply Technologies in emergencies - COMPENDIUM.
8.7.≈S7≈ Gravity - ( GWN - GTO ).
8.6.≈S6≈ Springwater - ( GWN - GTO ).
8.5.≈S5≈ Groundwater - ( GWN - GTO ).
8.4.≈S4≈ Brackish water, seawater - ( GWN - GTO ).
8.3.≈S3≈ Ponds, lakes and reservoirs - ( GWN - GTO ).
8.2.≈S2≈ Rivers and streams - ( GWN - GTO ).
8.1.≈S1≈ Rainwater - ( GWN - GTO ).