This reduced groundwater seepage to the drain and increased the proportion of shallow groundwater lost from the system via evapotranspiration.
Through this drainage system, the residual seepage flow is drained through boreholes dedicated to this purpose.
In case of a partially penetrating ditch drainage system receiving water from a ponded field, the streamlines have been observed to be poorly distributed along the flow profile with most of the seepage to the drains being confined to locations close to the drains.
On the basis of this work, end-of-storm pipe interceptor sewers of 0.25 m3/s (i.e., 21,600 m3/d) would be effective to tackle the problem of sewage connections and groundwater seepage to storm drains.
It was concluded that inappropriate sewage discharge and groundwater seepage into storm drains were approximately 17,860 m3/d (i.e., up to 51% of the total sewage flow in the catchment) and 3624 m3/d, respectively, and surface water backflow was up to an average 28,593 m3/d.
Prior to weir construction, groundwater seepage to the ditch drain was the main hydrological pathway for acid flux.
It is necessary, however, either to check or to harmlessly drain away the seepage water that would otherwise weaken the downstream parts of the dam and, in extreme cases, cause it to fail.
Sufficient air space was provided underneath the slide to drain away water seepage and prevent motion artifacts.
High hydraulic conductivity (>120 m per day) in the sulphuric horizons due to extensive macropores, combined with tidal modulation of drain water levels encouraged rapid seepage of acid groundwater.
With those new drains loomed the probability of irksome seepage.
