spacingspacing factorspacing of barsspadespadingspallspallingspalling resistancespalling stressspalling tensile stressspalling zonespanspan lengthspandrelspandrel beamsparsenessspatialspatial coordinatesspatial derivativespatial descriptionspatially varied flowspatially varied unsteady surface flowspatulaspecial capacity of a wellspecial equipmentspecial purpose outletspecial rapid hardening cementspecial structurespecialized concretespecific absorptionspecific areaspecific capacityspecific capacity of a wellspecific creepspecific dischargespecific drawdownspecific energyspecific energy curvespecific forcespecific force curvespecific gravityspecific headspecific heatspecific humidityspecific levelspecific massspecific permeabilityspecific resistivityspecific retentionspecific speed