13.-0640. Frequency.

13.- WASH Glossary.
13.-0639. French drain.
13.-0638. Freeboard.
13.-0637. Free-water surface constructed wetland.
13.-0636. Free residual chlorine - ( FRC ).
13.-0635. Free aquifer.
13.-0634. Framework issues.
13.-0633. Fractured aquifer.
13.-0632. Fracture.
13.-0631. Fracture flow.
13.-0630. Fouling.
13.-0629. Foul water blackwater.
13.-0628. Fossil groundwater.
13.-0627. Fossa alterna.
13.-0626. Formation.
13.-0625. Forebay.
13.-0624. Forage.
13.-0623. Food security.
13.-0622. Food products.
13.-0621. Food grade - ( silicone ).
13.-0620. Folded mountains.
13.-0619. Fog.
13.-0618. Fog drip.
13.-0617. Focus group.
13.-0616. Flywheel.
13.-0615. Flux.
13.-0614. Flux density.
13.-0613. Fluvial flooding.
13.-0612. Flushwater.
13.-0611. Flushing point.