These ponds are made of artificial substrata (reinforced concrete or hollows lined with plastic film) with pronounced slope angle at the margins (over 65 on average), which impedes the settlement of hydrophytic marginal vegetation, have small surface area (Appendix A) and are shallow (between 1.5 and 4 m depth). Their small size and primary function for irrigation determine marked water-level fluctuations and short water turnover time (~30 d) (Juan et al., 2012).