settlement chambers settelment
Pond water will flow from the bottom drains of the pond up the pipes in the direction of the red arrow as shown.
An ideal settlement chamber will be sloped from shallow to deep. The bottom drains will all face upwards and be located in the deep end of the settlement chamber, whilst at the opposite side on the shallow end of the chamber the exit pipe that feeds the primary mechanical filter stage will be located.
Being located higher than the bottom drain pipes increases the likelihood of the solids entering into the settlement chamber being collected in the deep end.
And YES, this does mean you need a waste flush valve located somewhere near the deep end of the settlement chamber so that you can flush all these nasty solids straight out and off to waste.