Concurrent with the extended rainy season we seem to be experiencing, workers came to tear up our hẻm (lane) and replace the storm sewer line. The existing line was not large enough to accommodate the torrential rains, resulting in minor flooding at times. Therefore the new line is welcome, although it has contributed to very messy conditions outside our front door (and tracked into the house) at times.
In addition to storm drainage, the line also takes the sewage from each of the houses on the hẻm. Each house has (or is supposed to have) a septic tank under the house which at least takes out the solids prior to drainage into the sewer line. However, I have rarely seen any pumpers in the neighborhood removing sludge from these tanks, so it is likely that many of the house septic tanks are no longer functioning properly.
After the old line is removed, the new line is installed at a fairly shallow depth, as was the old line. I never saw the water line, which indicates it is lower than the sewer, which is contrary to safe practice.
Each house sewer discharge (which includes large quantities of storm drainage at times) drains to these collector basins. Therefore each home owner was required to have his house sewer line rerouted as necessary to the new collector basins.
The contractor should be back soon to install new paving throughout the hẻm.