Labyrinth weirs with different crest shapes affect how well water flows through them. Circular-apex weirs are better than trapezoidal ones, with a 4.7% higher discharge coefficient. Half-round and WES crest profiles are more efficient than sharp-crest and quarter-round profiles, with 5.26% to 8.5% higher discharge coefficients. For easier construction, it's best to use a half-round profile. When the water level is high, all profiles create low pressure on the weir's walls. The half-round crest generates the highest negative pressure, while the sharp-crest profile increases pressure by 76%. The WES profile reduces the negative-pressure area by 50%.