The researchers pointed out that low-frequency processes, such as fluctuations instream flow and groundwater levels, would not usually be apparent to human populations.
研究人员指出，低频过程诸如河流流量和地下水水位的波动，通常不会对人类产生明显影响。
2
Groundwater commonly collects instream drainages but may remain entirely beneath the surface of dry stream-beds in arid regions.
地下水通常聚集在河流流域，但在干旱地区，地下水也可能完全保留在干涸河床的表面之下。
3
I think [instream advertising] will cause problems... confusion and resentment and so much more.