I think one of the major concerns of having a water garden installed could be what are some of possible maintenance issues that will arise after a few years of use. I remember a few years back talking to a landscaper who designed and installed water features. He mentioned that the old way of real rocks and liners has declined somewhat and they have gone mostly towards the fiberglass jobies. I, of course had to ask how the fiberglass types were working out for them. Well I got the answer that with the different weather elements nothing last very long and fiberglass does alot of fading and cracking. They see an average of 4-5 years before total replacement. Unfortunately, that is the mind set we have accepted and many of us have a difficult time knowing what polymers and combinations works best for a garden pond and waterfalls. With having so many years of plastic fabrication and making different polymers I look for a material base that is both easy and simple to repair while being user friendly for the home owner to maintain themselves. With our decorative waterfalls for the backyard, garden, patio and pool landscapes the maintenance if any ever arise is not much more then a 5 minute fix.