Through direct numerical simulations we investigate the effects of spatiotemporal intermittency as a result stable stratification in surface heated stratified open channel flow. By adapting density inversion criterion method Portwood et al. [ J. Fluid Mech. , vol. 807, 2016, R2] for our flow, demonstrate that flow may be robustly separated into regions active turbulence which $Re_B \gtrsim {O}(...