I've just come from a meeting with one of my developers...he's looking to convert a natural gully/semi-dry stream bed along a proposed nature trail into some sort of water feature. Approx. length is 500ft - falls steadily in a pleasing line about 35ft. I have completed waterfall projects w/vanishing streams prior to this request...but the length (500ft+), terrain and material/labor costs of fine grading, laying down bedding/underlayment and epdm fabric (as I would for a small streambed) make this different. I can create large holding ponds as needed (although have not done a true 'pond' prior to this), have the ability to evaluate water flow, pump requirements etc...what I'm wondering is how continuous water flow would effect the terrain w/no liner? I would expect a great deal of erosion...but this area is heavily wooded and this gully has obviously been there for some time - not related in anyway to recent development. Heavily wooded as well along the sides...would like to 'line' with the abundance of natural stone found on-site...perhaps create waterfalls along the way w/fabric and blackfoam. Of course we'd lose alot of water not only to evaporation but as it leeched into the soil along the way. Would numerous smaller holding areas more traditionally built (w/epdm) be effective spaced between longer runs of areas left 'natural'? I'm curious if anyone has ever done something similar? Not looking for pricing info...construction/troubleshooting advice would be GREATLY appreciated.