_RL GM_Visbeck_maxSlope
& GM_Visbeck_minDepth, GM_Visbeck_maxSlope,
IF ( GM_Visbeck_maxSlope.GT.0. _d 0 ) THEN
recipMaxSlope = 1. _d 0 / GM_Visbeck_maxSlope
Sloc = GM_Visbeck_maxSlope
GM_Visbeck_maxSlope = UNSET_RL
IF ( GM_Visbeck_maxSlope .EQ. UNSET_RL )
& GM_Visbeck_maxSlope = GM_maxSlope