Answer
The divergence is positive for the points above the $x$-axis and negative for the points below the $x$-axis.
Work Step by Step
The Divergence Theorem states that $\iint_S \overrightarrow{F}\cdot d\overrightarrow{S}=\iiint_Ediv \overrightarrow{F}dV $
Here, $S$ is a closed surface and $E$ is the region inside that surface.
$div F=\dfrac{\partial a}{\partial x}+\dfrac{\partial b}{\partial y}+\dfrac{\partial c}{\partial z}=\dfrac{\partial (xy)}{\partial x}+\dfrac{\partial b}{\partial (x+y^2)}=y+2y=3y$
When the net flow of water is inwards, then the divergence at that point will be negative. However, when the net flow of water is outwards, then the divergence at that point will be positive.
Also, when there is no net flow of water inwards or outwards, then the divergence at that point will be zero.
Hence, the divergence is positive for the points above the $x$-axis and negative for the points below the $x$-axis.
