I need some help modeling an underground detention system that will discharge into an underground gravel percolation bed surrounded by natural soils. I have my underground 72" pipe modeled with 4 orifices to disharge to the gravel per bed, but not sure how to model the gravel perc bed. Any suggestions?? Thanks for the help.
here's my take on it, hopefully someone more knowledgeable will weigh in as well to help you out:
i would model the gravel bed as a storage chamber, V=LxWxH is the volume (assuming rectalgular), and the available storage volume being V'=rxV, where r is the voids ratio (say 40% for gravel, then r=0.4). then for the surrounding soil, i would find its infiltration rate, say i in/hour, and use that as exfiltration in the model, something like "uniformly for pond bottom" is an option i remember. i do not have hydraflow or SSA in my home computer, but if you want, i can try and see if i can set up a model for you tomorrow.