Earth Wind Water Civil Engineering has completed the design of a large light industrial park near San Diego’s Brown Field, cargo airport. Similar to many of our previous projects in this area (called Otay Mesa) the transportation facility will meet a need created by the vast amount of import & export activity between the US and Mexico. Because of laws regarding transport drivers, it is often necessary for goods bought into the US from Mexico to park the trailer from an “18-wheeler” at a safe, secure location so it can be mated to an American trucking rig for transport to anywhere in the US. These facilities are often called “Transport Sites” or trailer drop-off locations. In any case, the result is a need for a vast parking area for these trailers.
Because the facilities are for truck-trailer parking the need to be quite flat. Large pads must be created and since the area has sloping terrain, large amounts of site grading are required. Earth Wind Water Civil Engineering does these designs using the latest in computer-assisted-design software. We use Autodesk’s Civil 3D 2020 design software, allowing all of the design to be done in true 3-dimensional accuracy. Further, this software allows us to “test” the usability of the parking areas using the software’s truck-vehicle tracking components to make sure that all locations where tractor-trailers will be parked can actually be navigated easily by the truck drivers. Compared to how this work was done a decade ago, this is an amazing feature and it helps to generate a better design while saving lots of time and effort.
Of course, the facility must also be designed so that it does not create polluted runoff that can impact adjacent streams and water-bodies. This is accomplished by our design of biofiltration areas (rain-gardens) of immense size. Then all partially treated storm water must be captured and detained until it can be discharged to the downstream areas in a location and manner that is similar to, but at lower flows then it did before the new project was constructed. California’s Water Pollution Control Board manages the MS4 permits in this area and they require that storm water leaving a developed site like this, do so at a rate of flow that mimics the conditions of the land “before anything was ever construction of the land. This is done by creating large sub-terranean tanks or vaults to temporarily store the rainwater. Then we perform a “continuous computer simulation” of all recorded rainfall amounts on record to prove to the State that the discharges range between 10% of the 2-year storm and the 10-year storm. This work is called “restoration hydromodification”. It sounds impossible but it is a routine requirement in California.