English: Outfall of the largest culvert in the world, discharging to the Estepona Playa central beach; the rio Monterroso embovedado at 3,805ft - 1,160 metres long, and possessing a 32 foot- 10 metre span.

The culvert outfall outputting fluids from different internal sources from deep within the subsurface canal. These include the main river Monterroso, freatics and utility line infiltration, lateral lines discharging a constant flow of domestic and business wastewater, residual cleaning runoff and general topographical water entries, E.G.; arroyo de Juan Benítez.

During the climax of tourist times typically in the summer, the local water utility workers take the necessary precautions to close up majority of the culvert entrances on the central beach with cement screen walls for security reasons.

Despite the river Monterroso completely loosing flow in the summer, the residual waters from third party water sources within the culvert continued to flow physically under these sealed barriers and begin to pool up in front of the paseo maratimo.

With 0% natural river water other than dwindling freatics, infiltration and topographic flows during the summer months, the waterborne domestic wastewater presence concentration, sources these internal domestic wastewater discharges rises large amounts.

Without the dilution of alternative water flows, the smell of hydrogen sulphide, methane and ammonia would fill the air. This had adverse effects on not only the tourism and the local community, but wildlife as the wastewater travelled under the sand under the sea. By 2008, canalizaciones work was carried out to prevent these problems.

The work to troubleshoot these problems involved constructing a horizontal, low capacity spillway internally within the culverts carrying three planned under the canalizaciones operation. The streams; arroyo de los Melonares, arroyo de Calancha, and the Rio Monterroso were all in target of this work and the successful works had done their job eliminating the flows during tourism season.

Specific to the Monterroso, the low capacity spillway was installed 45 metres distance from the beach outfall, to the east of the spillway is the interceptor output line. This line travels along a polyethylene pipe long the eastern wall of the culvert armoured with a small brick channel and cement mounts until it meets a manhole chamber, linking it to a main manhole chamber sending the excess waters into the sanitary sewer system. These works eliminated all of the complaints during the tourism seasons.

Copyright 2018, Leocrain E Thunderbolt; (R.E.S.)

Hydraulic inspector. All rights reserved.