A negative edge is often implemented for its rainwater harvesting capabilities, improving water quality, and its unique design element. The Negative Edge intake method consists of a pond that overflows into a constructed basin (done via waterfall).
This basin is similar however generally larger and more costly than your average pondless basin. When correctly implemented this intake option will give you great results as far as pre-filtrating, skimming, and re-oxygenating your system all while blending into the aesthetics of the ecosystem.